DE102021124917A1 - CHARGING CABLE FOR A CHARGING STATION, CHARGING STATION, MULTIPLE CHARGING STATIONS SYSTEM AND METHOD OF OPERATING A CHARGING STATION - Google Patents

Abstract

A charging cable (5) for a charging station (1) for charging an energy store (2) of an electric vehicle (3) with a DC charging voltage of at least 600 V in particular is proposed. The charging cable (5) is a coaxial cable with an inner conductor (DC+) and a hollow-cylindrical outer conductor (DC-), with the inner conductor (DC+) being designed for a first nominal voltage and the outer conductor (DC-) for a second nominal voltage, with the The quotient of the first nominal voltage and the second nominal voltage is in a range between 1.1 and 5, preferably in a range between 1.3 and 4, more preferably in a range between 1.6 and 3.

Description

TECHNICAL AREA

The invention relates to a charging cable for a charging station for charging an energy store of an electric vehicle, a charging station for charging an energy store of an electric vehicle, a system with a plurality of such charging stations and a method for operating a charging station for charging an electric vehicle.

STATE OF THE ART

The present technical field relates to charging an energy store of an electric vehicle. Different charging methods are known for electric vehicles, for example there are rapid charging methods in which the charging station provides the electric vehicle with direct voltage/current (DC), or alternatively alternating current charging methods in which the electric vehicle is supplied with single-phase or multi-phase, in particular two-phase or three-phase, alternating current (AC) is made available, which the charging vehicle converts into direct current for the energy storage device to be charged using a built-in AC/DC converter. With the AC charging process, a charging logic in the vehicle or the energy storage device controls the charging process.

In the following, only rapid charging methods in particular, in which the charging station makes direct voltage/current (DC) available to the electric vehicle, are discussed.

Bombardier, for example, describes this in the German patent application DE10151153A1 a DC charging station for electric vehicles with a transformer, with a rectifier or AC/DC converter, a DC intermediate circuit with a transformer and a downstream DC/DC converter.

Other conventional solutions are from the documents EP3175529B1 , US20190143822A1 , US9425641B2 and US9789774B2 known. All solutions from the prior art have in common that at least one transformer is integrated in the system, which forms a local IT network and thus no fault current flows in the event of a first fault.

In contrast to the prior art, a charging station with power electronics is used, which does not have a transformer. For this, please refer to the patent applications DE102021106275 .6 and DE102021108233.1 referred to the applicant.

Conventionally, in such rapid charging methods with a high DC charging voltage of, for example, 800 V, charging cables are used which have two parallel lines for DC+ and DC- arranged in the charging cable. But if in the event of an error, e.g. B. If the insulation of the charging cable breaks and the user touches one of these lines, DC+ or DC-, he touches a voltage of 400 V (in terms of amount). Such a voltage of 400 V can be fatal.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to improve the charging of an energy store of an electric vehicle

The object is achieved by a charging cable with the features of claim 1, by a charging station with the features of claim 7, by a system with a plurality of charging stations with the features of claim 17 and by a method for operating a charging station for charging an electric vehicle solved with the features of claim 19.

According to a first aspect, a charging cable for a charging station for charging an energy store of an electric vehicle with a DC charging voltage of at least 600 V in particular is proposed. The charging cable is a coaxial cable with an inner conductor and a hollow-cylindrical outer conductor, with the inner conductor being designed for a first nominal voltage and the outer conductor for a second nominal voltage, with the quotient of the first nominal voltage and the second nominal voltage being in a range between 1.1 and 5 is preferably in a range between 1.3 and 4, more preferably in a range between 1.6 and 3.

The charging cable as a coaxial cable with the inner conductor designed for the first nominal voltage and the outer conductor designed for the second nominal voltage is designed in such a way that with a high DC charging voltage of 800 V, for example, a higher DC voltage (e.g. 500 V ) on the inner conductor and a lower DC voltage (e.g. - 300 V) on the outer conductor.

Due to the design of the present charging cable as a coaxial cable with the inner conductor and the hollow-cylindrical outer conductor, a user will only touch the outer conductor in the event of a fault, for example if the charging cable insulation breaks, and thus touch a voltage that is smaller in amount. For example, the magnitude of the DC voltage carried on the outer conductor limited to 300V. In particular, this voltage is not life-threatening for the user.

When the user touches the live outer conductor, a fault current arises that can be detected. Depending on such a detection, a switching device, e.g. B. a contactor can be opened. Details on this are explained in more detail below.

In the present arrangement of the charging cable with the inner conductor and the outer conductor surrounding the inner conductor, the outer conductor protects the inner conductor. In other words, the outer conductor protects the user from touching the inner conductor, which can carry a higher DC voltage.

In particular, the inner conductor carries a positive DC voltage, whereas the outer conductor carries a negative DC voltage. Of course, it is also possible for the inner conductor to carry a negative DC voltage and the outer conductor to carry a positive DC voltage.

According to one embodiment, the inner conductor and the hollow-cylindrical outer conductor are embedded in an insulating plastic, with a PE conductor and a charge pilot signal line also being embedded in the plastic.

In this embodiment, the inner conductor lies on the longitudinal axis of the charging cable and forms the interior of the charging cable. The inner conductor is surrounded by a first layer of plastic. The first layer is then followed by the outer conductor. The outer conductor is then followed by a second layer of plastic. In this embodiment, the inner conductor, which preferably carries the higher DC voltage, is surrounded by two plastic layers and the outer conductor, which leads to corresponding protection for the user in the event of a fault.

According to a further embodiment, the charging cable comprises an interior space and an exterior space, with the hollow-cylindrical outer conductor delimiting the interior space, with a first layer of plastic separating the inner conductor and the outer conductor in the interior space, with the PE conductor and the charge pilot signal line in outside are embedded in a second layer of plastic.

According to a further embodiment, the PE conductor is designed as a hollow-cylindrical coaxial conductor which surrounds the outer conductor and is embedded in the second layer of the plastic.

According to a further embodiment, the charge pilot signal line and a plurality of temperature signal lines are embedded outside of the PE conductor in the second layer of plastic. Two temperature signal lines are preferably used to connect a temperature sensor.

According to a further embodiment, the hollow-cylindrical outer conductor is designed as a braiding made up of a plurality of conductors, in particular wires. The braid can also be referred to as a ladder braid. In this case, the braiding is preferably set up to contract when the charging cable is stretched.

• einen AC/DC-Wandler zum Wandeln einer von dem mehrphasigen Netz über die Phasen bereitgestellten Wechselspannung in eine mittels einer DC+-Leitung und einer DC--Leitung bereitgestellten Gleichspannung,
• eine Steuervorrichtung zum Steuern von Komponenten der Ladestation umfassend den AC/DC-Wandler, und
• ein Ladekabel gemäß dem ersten Aspekt oder einer der Ausführungsformen des ersten Aspekts.

According to a second aspect, a charging station without a transformer is proposed for charging an energy store of an electric vehicle with electrical energy by means of a multi-phase network that can be coupled to the charging station, which has:

• an AC/DC converter for converting an AC voltage provided by the multiphase network via the phases into a DC voltage provided by means of a DC+ line and a DC- line,
• a control device for controlling components of the charging station comprising the AC/DC converter, and
• a charging cable according to the first aspect or one of the embodiments of the first aspect.

The charging station can also be referred to as a transformerless DC charging station. The charging station without a transformer does not use a transformer to convert AC voltage into DC voltage, but instead uses the AC/DC converter and, optionally, a downstream DC/DC converter.

The AC/DC converter can also be referred to as a converter. The AC/DC converter is set up in particular for converting an AC voltage into a DC voltage and/or for converting a DC voltage into an AC voltage. The charging station comprises in particular an intermediate circuit connected downstream of the converter with a number of intermediate circuit capacitors which are connected to an intermediate circuit center point.

The DC voltage provided by the AC/DC converter or a DC voltage boosted based on this, boosted for example by a DC/DC converter, is used as the DC charging voltage for charging the energy store of the coupled electric vehicle.

Furthermore, the charging station can in particular have an energy measuring unit which is set up to measure the amount of energy drawn from the electric vehicle. In addition, a billing unit can also be provided in particular, which bills the user or customer for the energy consumed by the electric vehicle.

The charging station has, for example, a housing, in particular a waterproof housing, with an interior space in which the electrical and/or electronic components are arranged.

The charging station can also be referred to as a charging connection device. The charging station is designed in particular as a wall box. The charging station is suitable for charging or regenerating the energy store of an electric vehicle in that the charging station is electrically connected to the energy store or the charging electronics of the electric vehicle via its connection socket and the charging plug of the electric vehicle. The charging station acts as a source of electrical energy for the electric vehicle, with the electrical energy being able to be transferred to an energy store in the electric vehicle by means of a charging cable and charging plug. The charging station can also be referred to as an intelligent charging station for electric vehicles. The charging station can also draw energy from the electric vehicle and feed it back into the multi-phase network. Technically, this is referred to as Vehicle-to-Grid (V2G). In particular, the charging station can not only feed back into the grid, but also charge another vehicle, or supply another consumer, or charge another energy store. This process is also known as vehicle-to-anything/everything (V2X).

The multiphase network is, for example, a multiphase subscriber network. The multi-phase network can also be a multi-phase power supply network. In particular, the polyphase network has a number of phases, for example L1, L2 and L3, and a neutral conductor (also denoted by N).

• bei einer DC-Ladespannung von höchstens 600 V den AC/DC-Wandler und/oder den DC/DC-Wandler derart anzusteuern, dass die mit dem Innenleiter des Ladekabels gekoppelte DC+-Leitung oder gekoppelte DC--Leitung eine erste Gleichspannung führt und die mit dem Außenleiter des Ladekabels gekoppelte DC--Leitung oder gekoppelte DC+-Leitung eine zweite Gleichspannung führt, wobei die erste Gleichspannung und die zweite Gleichspannung unterschiedliche Vorzeichen und gleiche Beträge aufweisen, und
• bei einer DC-Ladespannung von mehr als 600 V den AC/DC-Wandler und/oder den DC/DC-Wandler derart anzusteuern, dass die mit dem Außenleiter des Ladekabels gekoppelte DC--Leitung oder gekoppelte DC+-Leitung eine dritte Gleichspannung mit einem Betrag von höchstens 300 V führt und die mit dem Innenleiter des Ladekabels gekoppelte DC+-Leitung oder gekoppelte DC--Leitung eine vierte Gleichspannung mit einem Betrag, welcher einem Differenzbetrag zwischen der DC-Ladespannung und der dritten Gleichspannung entspricht, führt, wobei die dritte Gleichspannung und die vierte Gleichspannung unterschiedliche Vorzeichen und unterschiedliche Beträge aufweisen.

According to one embodiment, the charging station includes a control unit that is set up to

• to control the AC/DC converter and/or the DC/DC converter at a DC charging voltage of no more than 600 V in such a way that the DC+ line coupled to the inner conductor of the charging cable or the coupled DC- line carries a first DC voltage and the the DC- line coupled to the outer conductor of the charging cable or the DC+ line coupled carries a second direct voltage, the first direct voltage and the second direct voltage having different signs and the same amounts, and
• to control the AC/DC converter and/or the DC/DC converter at a DC charging voltage of more than 600 V in such a way that the DC- line coupled to the outer conductor of the charging cable or the coupled DC+ line generates a third DC voltage with a amount of at most 300 V and the DC+ line coupled to the inner conductor of the charging cable or coupled DC- line carries a fourth DC voltage with an amount which corresponds to the difference between the DC charging voltage and the third DC voltage, the third DC voltage and the fourth direct voltage have different signs and different magnitudes.

Due to this control, the amount of direct voltage carried on the outer conductor is limited to a maximum of 300 V. In particular, this is not life-threatening. For example, if the DC charging voltage negotiated between the charging station and the electric vehicle is 800 V, then the third DC voltage can be -300 V, whereas the fourth DC voltage can be +500 V.

According to a further embodiment, the charging station comprises a DC/DC converter connected downstream of the AC/DC converter, an intermediate circuit coupled between the AC/DC converter and the DC/DC converter and having an intermediate potential, and a setting unit for setting the intermediate potential of the intermediate circuit such that the third direct voltage and the fourth direct voltage are symmetrical to the adjusted intermediate potential.

For the above example of the third DC voltage with - 300 V on the outer conductor and + 500 V on the inner conductor, the setting unit will shift the intermediate potential to + 100 V. Thus, the third DC voltage of -300 V and the fourth DC voltage of +500 V are symmetrical to the set intermediate potential of +100 V. This symmetrical setting increases the safety of the charging station system as a whole.

According to a further embodiment, the setting unit includes a voltage regulator which is set up to regulate the intermediate potential in such a way that it lies symmetrically between the third direct voltage and the fourth direct voltage.

The present voltage regulator enables the intermediate potential to be regulated to that value which is equidistant (in terms of the voltage magnitude) between the third direct voltage and the fourth direct voltage.

• einen den Phasen und dem Neutralleiter zugeordneten Fehlerstromsensor, welcher zum Erfassen eines zeitlich veränderlichen Fehlerstroms mit Gleichstromanteil und Wechselstromanteil eingerichtet ist, eine Schaltvorrichtung, welche zum Öffnen und Schließen der DC+-Leitung und der DC--Leitung der Ladestation eingerichtet ist,
• eine erste Einheit, welche zum Detektieren von sinusförmigen Wechselfehlerströmen und pulsierenden Gleichfehlerströmen in Abhängigkeit des erfassten Fehlerstroms und abhängig davon zum Bereitstellen eines ersten Ansteuersignals zum Ansteuern der Schaltvorrichtung zum Öffnen der DC+-Leitung und der DC--Leitung eingerichtet ist, und
• eine zweite Einheit, welche zum Detektieren von Gleichfehlerströmen in Abhängigkeit des erfassten Fehlerstroms und abhängig davon zum Bereit-stellen eines zweiten Ansteuersignals zum Ansteuern der Schaltvorrichtung zum Öffnen DC+-Leitung und der DC--Leitung eingerichtet ist, wobei die Steuervorrichtung zum Bereitstellen eines dritten Ansteuersignals zum Ansteuern der Schaltvorrichtung zum Öffnen der DC+-Leitung und der DC- -Leitung eingerichtet ist.

According to a further embodiment, the charging station comprises:

• a fault current sensor assigned to the phases and the neutral conductor, which is set up to detect a fault current that changes over time with a direct current component and an alternating current component, a switching device which is set up to open and close the DC+ line and the DC- line of the charging station,
• a first unit, which is set up to detect sinusoidal alternating fault currents and pulsating direct fault currents as a function of the fault current detected and, depending thereon, to provide a first control signal for controlling the switching device to open the DC+ line and the DC- line, and
• a second unit, which is set up to detect DC fault currents as a function of the fault current detected and, depending thereon, to provide a second control signal to control the switching device to open the DC+ line and the DC- line, the control device being set up to provide a third control signal is set up to drive the switching device to open the DC+ line and the DC- line.

• einen den Phasen und dem Neutralleiter zugeordneten Fehlerstromsensor, welcher zum Erfassen eines zeitlich veränderlichen Fehlerstroms mit Gleichstromanteil und Wechselstromanteil eingerichtet ist,
• eine weitere Schaltvorrichtung, welche zum Öffnen und Schließen der Phasen und des Neutralleiters der Ladestation eingerichtet ist,
• eine erste Einheit, welche zum Detektieren von sinusförmigen Wechselfehlerströmen und pulsierenden Gleichfehlerströmen in Abhängigkeit des erfassten Fehlerstroms und abhängig davon zum Bereitstellen eines ersten Ansteuersignals zum Ansteuern der weiteren Schaltvorrichtung zum Öffnen der Phasen und des Neutralleiters eingerichtet ist, und
• eine zweite Einheit, welche zum Detektieren von Gleichfehlerströmen in Abhängigkeit des erfassten Fehlerstroms und abhängig davon zum Bereitstellen eines zweiten Ansteuersignals zum Ansteuern der weiteren Schaltvorrichtung zum Öffnen der Phasen und des Neutralleiters eingerichtet ist,
• wobei die Steuervorrichtung zum Bereitstellen eines dritten Ansteuersignals zum Ansteuern der weiteren Schaltvorrichtung zum Öffnen der Phasen und des Neutralleiters eingerichtet ist.

According to a further embodiment, the charging station comprises:

• a fault current sensor assigned to the phases and the neutral conductor, which is set up to detect a fault current that varies over time with a direct current component and an alternating current component,
• another switching device that is set up to open and close the phases and the neutral conductor of the charging station,
• a first unit which is set up to detect sinusoidal alternating residual currents and pulsating direct residual currents as a function of the fault current detected and, depending thereon, to provide a first control signal for controlling the further switching device to open the phases and the neutral conductor, and
• a second unit, which is set up to detect DC fault currents as a function of the detected fault current and, depending thereon, to provide a second control signal for controlling the further switching device to open the phases and the neutral conductor,
• wherein the control device is set up to provide a third control signal to control the further switching device to open the phases and the neutral conductor.

In the present embodiment of the charging station, only a single residual current sensor and a single switch-off device are advantageously used to detect sinusoidal alternating residual currents, pulsating direct residual currents and direct residual currents and to switch off the DC+ line and the DC- line and/or the phases and the neutral conductor when a fault is detected , for example a DC contactor. In addition, this single switch-off device is also used by the functional controller, which is designed in particular as part of the control device. For double isolation, the AC/DC converter and/or DC/DC converter can be controlled by the functional control in such a way that it also acts as a switch.

The fault current sensor can also be referred to as an all-current sensitive fault current sensor. The switching device can also be referred to as a switching element. The switching device is preferably designed in such a way that, in the event of a mains voltage failure, it opens, in particular automatically, and can thus establish a safe state.

Examples of the electrical and/or electronic components of the charging station include the switching device, for example a contactor or relay, connection terminals, electronic circuits, the residual current sensor, a communication module, a communication interface, a user interface, an EMC filter and at least one power supply. The control device comprises, for example, a printed circuit board on which a plurality of electronic components for controlling and/or measuring and/or monitoring the energy states at the charging station or in the connected electric vehicle are arranged, as well as an authentication device such as an RFID/NFC reader/Bluetooth module or an automated authorization process via high-level communication, in particular according to the ISO15118 standard, or according to the plug-and-charge principle and the like.

The third control signal is in particular depending on a vehicle authentication and / or vehicle verification or user authentication and / or user verification, depending on an overcurrent monitoring and / o which is generated depending on a correct connection of the charging cable to the electric vehicle and/or to the charging station. The vehicle authentication and/or vehicle verification or user authentication and/or user verification ensures that only a valid user or an electric vehicle known to the charging station is allowed to charge at the charging station. One or more of the following technologies can be used for vehicle authentication and/or vehicle verification, user authentication and/or user verification: RFID, Bluetooth, code entry, fingerprint reader, vein scanner or the like. An electric vehicle can, for example, transmit its ID via high-level communication, in particular ISO 15118, or according to the plug-and-charge principle.

ISO 15118 can be used to detect when the electric vehicle does not adhere to a negotiated charging plan. Correct connection of the charging cable to the electric vehicle and/or to the charging station can be detected, for example, by means of a plug-present sensor and/or a charge pilot signal and/or the locking detection unit.

According to one embodiment, the control device is set up to control the AC/DC converter by means of a control signal generated as a function of the opening signal, in particular to switch it off in the event of a fault. The AC/DC converter thus acts like a mechanical switch and provides a second isolation in the power path.

According to one embodiment, the control device is set up to control the AC/DC converter using a control signal generated as a function of the opening signal and/or to control a DC/DC converter connected downstream of the AC/DC converter with a control signal generated as a function of the opening signal steer. Thus, both the AC/DC converter and the DC/DC converter act as mechanical switches and provide further isolation in the power path.

According to a further embodiment, the charging station comprises a control circuit which is set up to control the switching device, if at least one of the control signals is provided, by means of an opening signal in such a way that the DC+ line and the DC- line open, the phases and the neutral conductor can also be opened. In addition, the power electronics can be switched off in that a control signal generated as a function of the opening signal opens them. This results in a double isolation of the vehicle from the network.

The control circuit accordingly controls the switching device to open the DC+ line and the DC- line and/or the phases and the neutral conductor when one or more of the control signals is provided or set. A provided control signal is therefore sufficient to open the DC+ line and the DC- line of the charging station and to create a safe state.

According to a further embodiment, in addition to the switching device in the DC circuit, a further switching device is provided in the AC circuit, which is set up to open and close the phases and the neutral conductor of the charging station.

The control circuit is preferably set up to control the further switching device, if at least one of the control signals is provided, by means of an opening signal in such a way that it opens the phases and the neutral conductor of the charging station.

According to a further embodiment, five connection terminals are provided for the three phases, the neutral conductor and a PE conductor, with the residual current sensor being connected downstream of the connection terminals, the AC/DC converter being downstream of the residual current sensor, the switching device being downstream of the AC/DC converter and the terminal strip of the switching device is connected downstream, and the charging cable is connected to the terminal strip, in particular is firmly connected or attached.

According to a further embodiment, the control device is set up to control, in particular to switch off, the AC/DC converter by means of a control signal generated as a function of the opening signal.

In particular, the control device switches off the AC/DC converter using the control signal when the opening signal is set. In other words, the control device switches off the AC/DC converter when at least one of the control signals is provided.

According to a further embodiment, the charging station comprises an insulation breakage sensor assigned to the charging cable for providing an insulation breakage sensor signal which is indicative of an insulation breakage of the charging cable.

A break in the insulation of the charging cable is, for example, a break in a cable sheath of the charging cable or a break in the insulation on the charging plug of the charging cable.

According to a further embodiment, the charging station alternatively or additionally comprises an insulation rupture sensor assigned to the housing of the charging station, which is set up to provide an insulation rupture sensor signal which is indicative of damage to the insulation of the housing of the charging station.

According to a further embodiment, the charging station includes an evaluation unit which is set up to evaluate the provided insulation breakage sensor signal to determine an insulation breakage of the charging cable and/or the housing of the charging station. In this case, the control device is preferably set up to provide the third control signal as a function of a determined break in the insulation.

Accordingly, if the evaluation unit detects an insulation break on the charging cable, its charging plug and/or on the housing of the charging station, the third control signal is provided by the control device so that the control circuit controls the switching device in such a way that it connects the DC+ line and DC --Charging station line opens.

According to a further embodiment, five connection terminals are provided for the three phases, the neutral conductor and a PE conductor, with an EMC filter downstream of the five connection terminals being provided, the residual current sensor being downstream of the EMC filter, the further switching device being downstream of the residual current sensor, the AC/DC converter is connected downstream of the further switching device, a DC/DC converter is provided downstream of the AC/DC converter, the switching device is connected downstream of the DC/DC converter, a further EMC filter is provided downstream of the switching device, and the terminal strip to which the charging cable is connected is connected downstream of the further EMC filter.

The DC/DC converter is set up in particular to step up the direct voltage provided by the AC/DC converter and to provide it as a DC charging voltage on the output side. The DC/DC converter can also be referred to as a DC voltage converter.

According to a further embodiment, the control circuit is set up to control the switching device and the further switching device, if at least one of the control signals is provided, by means of the opening signal in such a way that they open the DC+ line and the DC- line, as well as through the second Switching device the phases and the neutral conductor.

If at least one of the control signals is provided (or set) in this embodiment, the control circuit controls both the switching device and the additional switching device, so that they control the DC+ line and the DC- line as well as the phases and the neutral conductor of the Open charging station. In addition, the AC/DC converter and the DC/DC converter can also be switched off accordingly. This further increases the safety of the charging station.

1. a) einen elektromagnetischen Antrieb des ersten Leistungsschaltelements mittels eines ersten Ansteuersignals mit einer Anziehspannung anzusteuern, um das erste Leistungsschaltelement von dem nicht-leitenden Schaltzustand in den leitenden Schaltzustand zu verbringen,
2. b) den elektromagnetischen Antrieb des ersten Leistungsschaltelements mittels des ersten Ansteuersignals mit einer gegenüber der Anziehspannung verringerten Haltespannung anzusteuern, nachdem das erste Leistungsschaltelement in dem leitenden Schaltzustand ist, und
3. c) das zweite Leistungsschaltelement mittels eines zweiten Ansteuersignals anzusteuern, um das zweite Leistungsschaltelement von dem nicht-leitenden Schaltzustand in den leitenden Schaltzustand zu verbringen, nachdem ein Stromfluss durch den elektromagnetischen Antrieb des ersten Leistungsschaltelements betraglich einen bestimmten Schwellwert erreicht oder unterschreitet.

According to a further embodiment, the switching device is designed as a first electrically controllable power switching element and the further switching device is designed as a second controllable power switching element. In this case, the first power switching element is an electromagnetically switching power switching element, each of the power switching elements having a non-conductive switching state in which no current can flow and a conducting switching state in which current can flow, each of the power switching elements for interrupting a flow of energy through the Charging station is set up for the energy storage of the electric vehicle. The control device is set up to:

1. a) to control an electromagnetic drive of the first power switching element by means of a first control signal with a pull-in voltage in order to bring the first power switching element from the non-conductive switching state to the conducting switching state,
2. b) to control the electromagnetic drive of the first power switching element by means of the first control signal with a holding voltage that is lower than the pull-in voltage after the first power switching element is in the conductive switching state, and
3. c) to control the second power switching element by means of a second control signal in order to bring the second power switching element from the non-conductive switching state to the conducting switching state after a current flow through the electromagnetic drive of the first power switching element has reached or fallen below a specific threshold value.

For steps a) and b), the first control signal can in particular have different amplitudes. Alternatively or additionally, the first control signal can also be modulated differently in steps a) and b), for example by using PWM modulation (PWM; pulse width modulation).

This embodiment has the advantage that the first power switching element is already being driven with a reduced holding current due to the reduced holding voltage at the time when the second power switching element is brought into the conducting switching state and can therefore be switched off more quickly. Since energy can only flow through the charging station when the second power switching element is conductive, in the event of a fault occurring immediately afterwards, such as a short circuit or a ground fault in the electric vehicle to be charged or the like, the first power switching element can be switched off more quickly than it is is possible without this embodiment. This increases the operational safety of the charging station.

The term “power switching element” is understood in particular to mean that switches are involved that can switch an electrical load on or off. In the conductive state, which can also be referred to as the switched-on state, electrical power can flow through the switching element, which can be in the range from a few watts to several kilowatts, for example up to 500 kW. This is to be seen in contrast to pure signal switches, which are only suitable for switching signals whose electrical power is well below one watt.

The term “electrically controllable power switching element” means, for example, a switching element that can be switched via a corresponding electrical control or control circuit. Examples of electrically controllable switching elements are electromechanical relays and electronic switches, which can also be referred to as semiconductor relays.

The term "electromagnetically switching power switching element" is understood to mean, for example, a relay or a contactor that has a mechanical actuating element that can be actuated by a magnetic field that can be generated by an electromagnet, in particular a coil. When the actuator is actuated, it closes the switchable contacts so that the relay or contactor is switched on. The actuating element can also be referred to as an armature and the switchable contacts can also be referred to as working contacts. In the non-conductive state, which can also be referred to as the switched-off or open state, the normally open contacts are separated by a gap, the size of the gap depending on the maximum operating voltage applied to the normally open contacts and the required current breaking capacity of the Switching element is determined.

The fact that each of the power switching elements is set up to interrupt an energy flow means in particular that the charging station does not transmit any energy when at least one of the two power switching elements is switched off, ie is in the non-conductive state. This is achieved, for example, in that the two power switching elements are connected in series with respect to the flow of energy through the charging station.

According to a further embodiment, the housing of the charging station is doubly insulated.

According to a further embodiment, the charging cable, together with its charging plug, is doubly insulated.

In accordance with a further embodiment, the drive circuit comprises a wired-OR link which ORs the first drive signal, the second drive signal and the third drive signal.

According to a further embodiment, the first unit is set up to emulate a type A residual current circuit breaker, in particular according to standard 61008-1.

In the present case, emulation of a type A residual current circuit breaker is to be understood in particular as emulating the type A residual current circuit breaker, for example emulating the error analysis functionality of the type A residual current circuit breaker in software.

In particular, the first unit and/or the second unit are designed as part of the control device. For example, the first unit and the second unit are implemented in software. Alternatively, the first and/or the second unit can be in the form of an FPGA or an ASIC.

According to a further embodiment, the second unit is set up to be a direct current detection device, preferably a residual direct current detection device in accordance with the IEC 62955 standard, particularly preferably a residual direct current monitoring device in accordance with the IEC 62955 standard , to emulate.

In the present case, emulating a direct current detection device means, in particular, simulating the direct current detection device, for example the residual direct current detection device in accordance with the IEC 62955 standard or the residual direct current monitoring device in accordance with the IEC 62955 standard, in software to understand.

According to another embodiment, the charging station comprises a module that integrates the first unit and the second unit and is adapted to have a type B residual current circuit breaker, in particular according to standard EN 61008-1 and/or according to standard EN 62423 train error protection. The module of the present embodiment accordingly forms or simulates the fault protection of the type B residual current circuit breaker, for example in accordance with standard EN 61008-1 or in accordance with standard EN 62423. The module is designed, for example, as part of the control device. The module can be implemented in software and/or in hardware.

According to a further embodiment, the charging station includes a current measuring device for measuring the current flowing on the phases in the direction of flow to the electric vehicle. The current measuring device is a useful current sensor.

According to a further embodiment, the switching device is designed as a contactor, as a four-phase relay or by four relays for the three phases and the neutral conductor.

According to a further embodiment, the charging station includes a test unit which is set up to inject and evaluate a test current in at least one of the phases, in the neutral conductor and/or in a separate test winding of the residual current sensor.

According to a further embodiment, the test unit is set up to be triggered for testing by means of a test command for simulating a pressing of a test button.

The test command is in particular a software command, by means of which the test unit can be triggered in such a way that it triggers the testing and thus the injection of the test current. The test command thus emulates the test button known from conventional type A residual current circuit breakers. The conventional mechanical test button is therefore advantageously not necessary, particularly in this embodiment.

For example, the test command can be generated via any form of backend and transmitted to the charging station. An example of this is when a user transmits the test command to the charging station via a smartphone app. According to a further example, the operator of the charging station transmits the test command at regular intervals via his server to the charging station coupled to the server. According to a further example, the charging station always terminates a charging process by completely testing the safety chain and sending a current to the test unit via a software command from the control device. The test unit then injects the test current, the test current is detected by the sensor and the contactor is tripped. As a result, a test with an actual current flow interruption is preferably always carried out at the end of the charging process.

According to a further embodiment, the charging station comprises an electromechanical system for mechanically displaying the switching position of the switching device. The electromechanics include a bezel controlled via an electrical coupling of the feedback contacts of the switching device, which follows the switch position of the switching device, and a visual indicator controlled by the bezel for indicating the switch position.

The visual display device includes, for example, two LEDs that light up green and red. The panel always covers one of the two LEDs. The LED not covered by the bezel is visible to the user. Due to the electrical coupling of the panel with the feedback contacts of the switching device, the panel always follows the switching position of the switching device. As a result, the screen controls the visual display device and shows, in particular by means of the colors red and green, the switching position of the switching device, for example the contactor.

According to a further embodiment, the electromechanics are coupled to an energy store, so that the electromechanics are suitable for maintaining the display of the switching position of the switching device for a predetermined time even when the charging station is in a de-energized state. The energy store is designed as a battery, for example.

For example, an electrical coupling of a mechanical display (e.g. a bistable lifting magnet with a color coding (red/green) on the armature) and a screen, which only shows one color at a time, are provided on the feedback contacts of the switching device in combination with an energy storage device which, in the event of a failure of the supply ensures that the switching device is monitored for a while and the display takes place. The final state of the relay is open when de-energized, unless it is welded, in which case it remains stably closed - both are feasible with a limited energy store.

According to a further embodiment, the test current is a pulsed, high-frequency alternating current which has a frequency of 1 to 5 kHz and a maximum duration of 10 ms. The test current is thus designed in particular in this way forms that it is not interpreted as a residual current. The test current is in particular a signal that cannot occur in practice and therefore cannot be interpreted as an error.

• durch einen Summenstrom-Wandler zum Bereitstellen des zeitlich veränderlichen Fehlerstroms, oder
• durch vier Stromwandler für die drei Phasen und den Neutralleiter zum Bereitstellen eines jeweiligen Ausgangssignals und eine den vier Stromwandlern nachgeschaltete Addiereinheit zum Bereitstellen des zeitlich veränderlichen Fehlerstroms durch Addition der von den vier Stromwandlern bereitgestellten Ausgangssignale.

According to a further embodiment, the fault current sensor is designed:

• by a summation current converter to provide the fault current that varies over time, or
• by four current transformers for the three phases and the neutral conductor for providing a respective output signal and an adder unit downstream of the four current transformers for providing the fault current that varies over time by adding the output signals provided by the four current transformers.

According to a further embodiment, the charging station comprises a communication module which is set up either to specify an energy consumption quantity for the electric vehicle by means of PWM signals or to negotiate a charging plan with charging electronics of the electric vehicle coupled to the charging station in accordance with ISO 15118. Negotiation takes place as described in ISO 15118. For example, the charging electronics of the energy store requests a certain charging power via the communication module from the charging station and the charging station, for example the control device of the charging station, determines whether the requested charging power can be provided. A current state of the subscriber network and/or the power supply network is taken into account in particular. If the requested charging power cannot be provided, the charging station can make a "counter-suggestion" via the communication module, which can be accepted by the charging electronics of the energy storage device, or the charging electronics can make its own request again. In this way, the charging station and the charging electronics communicate until the charging plan is negotiated. Negotiating the charging plan can be part of the pairing process when a battery is reconnected to the charging station.

• eine Kommunikationsschnittstelle, welche dazu eingerichtet ist, Daten mit einem Endgerät des Benutzers und/oder einem Server, welcher insbesondere die Ladestation verwaltet, auszutauschen,
• eine Benutzerschnittstelle für Eingaben eines Benutzers und/oder für Ausgaben an den Benutzer, und/oder
• ein Netzteil, welches dazu eingerichtet ist, eine über die Phasen bereitgestellte Wechselspannung in eine vorbestimmte Gleichspannung für die Steuervorrichtung und/oder die Komponenten der Ladestation bereitzustellen.

According to a further embodiment, the charging station has:

• a communication interface which is set up to exchange data with a terminal device of the user and/or a server which in particular manages the charging station,
• a user interface for input from a user and/or for output to the user, and/or
• a power pack which is set up to convert an AC voltage provided via the phases into a predetermined DC voltage for the control device and/or the components of the charging station.

According to a further embodiment, the control device of the charging station is set up to transmit the opening signal, if at least one of the control signals is provided, via the communication interface to the electric vehicle, by means of which a switching device installed in the electric vehicle, for example a DC vehicle contactor, can be opened.

This means that if, in the event of a fault, the switching element and/or the further switching element is opened by the opening signal, this opening signal is also transmitted via the communication interface to the electric vehicle, which then opens the DC vehicle contactor installed in the electric vehicle. This ensures that the charging cable is potential-free both on the part of the charging station, in particular the network, and on the part of the electric vehicle, in particular the battery located around the electric vehicle.

The respective unit, for example the first unit or the second unit, can be implemented in terms of hardware and/or software. In the case of a hardware implementation, the unit can be designed as a device or as part of a device, for example as a computer or as a microprocessor or as part of the control device. In the case of a software implementation, the unit can be embodied as a computer program product, as a function, as a routine, as part of a program code or as an executable object.

According to a third aspect, a system is proposed with a plurality N of charging stations (with N>2), the respective charging station being designed according to the second aspect or one of the embodiments of the second aspect.

According to a development, the N charging stations are connected by means of a star connection to a single circuit breaker, which is coupled to the grid connection point. By designing the charging station according to the first aspect or according to one of the embodiments of the first aspect, it is possible to couple the N charging stations by means of the star connection and to secure them with a single circuit breaker from the grid connection point.

• a) Ermitteln einer aktuellen DC-Ladespannung zum Laden des mit der Ladestation gekoppelten Elektrofahrzeuges,
• b) Feststellen, ob die ermittelte aktuelle DC-Ladespannung kleiner als 600 V ist,
• c1) falls die ermittelte aktuelle DC-Ladespannung kleiner als 600 V ist, Ansteuern des AC/DC-Wandlers derart, dass die mit dem Innenleiter des Ladekabels gekoppelte DC+-Leitung oder gekoppelte DC--Leitung eine erste Gleichspannung führt und die mit dem Außenleiter des Ladekabels gekoppelte DC--Leitung oder gekoppelte DC+-Leitung eine zweite Gleichspannung führt, wobei die erste Gleichspannung und die zweite Gleichspannung unterschiedliche Vorzeichen und gleiche Beträge aufweisen, und
• c2) falls die ermittelte aktuelle DC-Ladespannung größer als oder gleich 600 V ist, Ansteuern des AC/DC-Wandlers derart, dass die mit dem Außenleiter des Ladekabels gekoppelte DC--Leitung oder gekoppelte DC+-Leitung eine dritte Gleichspannung mit einem Betrag von höchstens 300 V führt und die mit dem Innenleiter des Ladekabels gekoppelte DC+-Leitung oder gekoppelte DC--Leitung eine vierte Gleichspannung mit einem Betrag, welcher einem Differenzbetrag zwischen der DC-Ladespannung und der dritten Gleichspannung entspricht, führt.

According to a fourth aspect, a method for operating a charging station for charging an energy store of an electric vehicle is provided proposed electrical energy by means of a multi-phase network that can be coupled to the charging station. The charging station includes an AC/DC converter for converting an AC voltage provided by the multiphase network via the phases into a DC voltage provided by means of a DC+ line and a DC- line, a control device for controlling components of the charging station comprising the AC/DC - Converter and a charging cable according to the first aspect or one of the embodiments of the first aspect. The charging station is designed in particular according to the second aspect or one of the embodiments of the second aspect. The procedure includes the steps:

• a) determining a current DC charging voltage for charging the electric vehicle coupled to the charging station,
• b) Determining whether the determined current DC charging voltage is less than 600 V,
• c1) if the determined current DC charging voltage is less than 600 V, controlling the AC/DC converter in such a way that the DC+ line coupled to the inner conductor of the charging cable or the coupled DC- line carries a first direct voltage and that to the outer conductor the charging cable coupled DC- line or coupled DC+ line carries a second DC voltage, the first DC voltage and the second DC voltage having different signs and the same amounts, and
• c2) if the determined current DC charging voltage is greater than or equal to 600 V, controlling the AC/DC converter in such a way that the DC- line coupled to the outer conductor of the charging cable or the coupled DC+ line generates a third DC voltage with an amount of carries a maximum of 300 V and the DC+ line coupled to the inner conductor of the charging cable or coupled DC- line carries a fourth DC voltage with an amount which corresponds to a difference between the DC charging voltage and the third DC voltage.

The embodiments described for the proposed charging station apply accordingly to the proposed method. Furthermore, the definitions and explanations for the charging station also apply accordingly to the proposed method.

"A" is not necessarily to be understood as being limited to exactly one element. Rather, a plurality of elements, such as two, three or more, can also be provided. Any other count word used here should also not be understood to mean that there is a restriction to precisely the stated number of elements. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

Further possible implementations of the invention also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

• 1 zeigt schematisch eine Anordnung mit einer ersten Ausführungsform einer Ladestation und einem Elektrofahrzeug;
• 2 zeigt eine schematische Schnittansicht einer ersten Ausführungsform eines Ladekabels für eine Ladestation;
• 3 zeigt eine schematische Schnittansicht einer zweiten Ausführungsform eines Ladekabels für eine Ladestation;
• 4 zeigt ein schematisches Schaltbild einer zweiten Ausführungsform einer Ladestation zum Laden eines Energiespeichers eines Elektrofahrzeuges;
• 5 zeigt ein schematisches Schaltbild einer dritten Ausführungsform einer Ladestation zum Laden eines Energiespeichers eines Elektrofahrzeuges; und
• 6 zeigt ein schematische Ansicht einer Ausführungsform eines Verfahrens zum Betreiben einer Ladestation.

Further advantageous refinements and aspects of the invention are the subject matter of the dependent claims and of the exemplary embodiments of the invention described below. The invention is explained in more detail below on the basis of preferred embodiments with reference to the enclosed figures.

• 1 shows schematically an arrangement with a first embodiment of a charging station and an electric vehicle;
• 2 shows a schematic sectional view of a first embodiment of a charging cable for a charging station;
• 3 shows a schematic sectional view of a second embodiment of a charging cable for a charging station;
• 4 shows a schematic circuit diagram of a second embodiment of a charging station for charging an energy store of an electric vehicle;
• 5 shows a schematic circuit diagram of a third embodiment of a charging station for charging an energy store of an electric vehicle; and
• 6 shows a schematic view of an embodiment of a method for operating a charging station.

Elements that are the same or have the same function have been provided with the same reference symbols in the figures, unless otherwise stated.

1 shows schematically an arrangement with a first embodiment of a charging station 1 and an electrical energy store 2 of an electric vehicle 3.

In the example of 1 a multi-phase subscriber network 4 is connected to a multi-phase power supply network 7 by means of a network connection point 6 . The multi-phase subscriber network 4 has, in particular, a number of phases, for example L1, L2 and L3, and one Neutral conductor N. In this example, without loss of generality, it is a matter of three-phase power grids. The electric vehicle 3 is connected by means of a charging cable 5, which is connected to a terminal strip 16 (not shown in Fig 1 , see for example in 4 ) of charging station 1 is connected to charging station 1.

The charging station 1 can have a number of electrical and/or electronic components (not shown in 1 , see for example in 4 ) and is set up to charge the energy store 2 of the electric vehicle 3 with electrical energy by means of the multi-phase subscriber network 4 coupled to the charging station 1 .

The housing of the charging station 1 is in particular doubly insulated. Furthermore, the charging cable 5 together with its charging plug 17 (see, for example, 4 ) also preferably double insulated. The power-carrying conductors (DC+ line and DC- line) in the charging connector 17 are individually insulated, and the housing of the charging connector 17 also has an insulating effect. The charging plug 17 can also be encapsulated on the inside with an insulating compound.

2 shows a schematic sectional view of a first embodiment of a charging cable 5 for a charging station 1, for example, the charging station 1 after 1 .

The charging cable 5 of 2 is a coaxial cable and has an inner conductor DCI and a hollow-cylindrical outer conductor DCA. The hollow-cylindrical outer conductor DCA is preferably in the form of a braid made up of a plurality of conductors, for example wires.

The inner conductor DCI and the hollow-cylindrical outer conductor DCA are embedded in an insulating plastic K1, K2. In addition, the charging cable has 5 of the 2 a PE conductor PE and a charge pilot signal line CP, both of which are also embedded in the plastic K1, K2. The charging cable 5 also has an interior space IR and an exterior space AR. The hollow-cylindrical outer conductor DCA delimits the inner space IR. In the interior IR, a first layer K1 of the plastic separates the inner conductor DCI and the outer conductor DCA. The PE conductor PE and the charge pilot signal line CP are in the 2 embedded in the outer space AR in a second layer K2 of the plastic.

The inner conductor DCI is designed for a first nominal voltage and the outer conductor DCA is designed for a second nominal voltage. The quotient of the first nominal voltage and the second nominal voltage is in a range between 1.1 and 5, preferably in a range between 1.3 and 4, more preferably in a range between 1.6 and 3.0.

In 3 is a schematic sectional view of a second embodiment of a charging cable 5 for a charging station 1, for example the charging station 1 after 1 , shown.

Also the charging cable 5 of the 3 is a coaxial cable with an inner conductor DCI and a hollow cylindrical outer conductor DCA.

The inner conductor DCI and the hollow-cylindrical outer conductor DC- are embedded in an insulating plastic K1, K2. In addition, the charging cable has 5 of the 3 a hollow-cylindrical PE conductor PE, a charge pilot signal line CP and a plurality of temperature signal lines T, both of which are also embedded in the plastic K1, K2. Furthermore, the charging cable 5 has an interior space IR and an exterior space AR. The hollow-cylindrical outer conductor DCA delimits the inner space IR. In the interior IR, a first layer K1 of the plastic separates the inner conductor DCI and the outer conductor DCA.

The inner conductor DCI is designed for a first nominal voltage and the outer conductor DCA is designed for a second nominal voltage. The quotient of the first nominal voltage and the second nominal voltage is in a range between 1.1 and 5, preferably in a range between 1.3 and 4, more preferably in a range between 1.6 and 3.0.

The PE conductor of the charging cable 1 after 3 is designed as a hollow-cylindrical coaxial conductor surrounding the outer conductor DCA. This is embedded in the second layer K2 of the plastic.

The charge pilot signal line CP of 3 Like the plurality of temperature signal lines T, it is embedded outside of the PE conductor PE in the second layer K2 of the plastic.

4 shows a schematic circuit diagram of a second embodiment of a charging station 1 for charging an energy store 2 of an electric vehicle 3. The second embodiment of the charging station 1 of FIG 4 includes all features of the first embodiment of the charging station 1 after 1 .

The charging station 1 of 4 has five input-side connection terminals 10a, 10b, 10c, 10d, 10e for coupling the phases L1, L2, L3, the neutral conductor N and the PE conductor PE of the polyphase network 4.

On the output side, the charging station 1 has a terminal strip 16 to which the charging cable 5 together with its charging plug 17 is attached.

Between the connection terminals 10a, 10b, 10c, 10d, 10e and the terminal block 16 are an EMC filter 24, an EMC filter 24 downstream residual current sensor 9, a residual current sensor 9 downstream further switching device 8, a further switching device 8 downstream AC / DC converter 15, a DC/DC converter 25 downstream of the AC/DC converter 15, a switching device 26 downstream of the DC/DC converter 25 and a further EMC filter 27 downstream of the switching device 26 are provided.

Furthermore, a current measuring device (not shown) can also be provided, which is set up to measure the electric current flowing on the phases L1, L2, L3 in the direction of flow to the electric vehicle 3. The current measuring device is a useful current sensor and is set up to measure the electric current flowing on the phases L1, L2, L3 in the direction of flow to the electric vehicle 3.

On the output side, the charging station 1 has the charging cable 5 with a charging plug 17 for connection to the electric vehicle 3. The charging cable 5 is, for example, according to FIG 2 or the 3 educated.

The AC/DC converter 15 converts the AC voltage provided by the multi-phase network 4 via the phases L1, L2, L3 into a DC voltage and provides this as a positive DC voltage DC+ and a negative DC voltage DC via two output lines, also referred to as DC+ and DC-, the DC/DC converter 25 ready.

The switching device 26 downstream of the DC/DC converter 25 is suitable for opening and closing the DC+- line DC+ and the DC- line DC- of the charging station 1 . The switching device 26 is a contactor, for example, or consists of relays for switching off the DC voltage. The switching device 26 is arranged on the DC side of the charging station 1 and can also be referred to as a DC switching device. The DC switching device is a contactor, for example.

The fault current sensor 9 is assigned to the phases L1, L2, L3 and the neutral conductor N and is set up to detect a fault current F that varies over time and has a direct current component and an alternating current component. The residual current sensor 9 is a summation current transformer, for example.

Furthermore, the charging station 1 includes the 4 a first unit 11, a second unit 12 and a control device 13. The control device 13 is in particular the central control device of the charging station 1 for controlling the electrical and/or electronic components of the charging station 1. The first unit 11 and the second unit 12 can - like in 4 shown - be formed externally to the control device 13 . Alternatively, the first unit 11 and the second unit 12 are designed as part of the control device 13 .

The first unit 11 is designed to detect sinusoidal alternating residual currents and pulsating direct residual currents as a function of the detected fault current F and, depending thereon, to provide a first control signal A1 for controlling the switching device 26 to open the DC+ line DC+ and the DC- line DC-. In this case, the first unit 11 is preferably set up to emulate a type A residual current circuit breaker, preferably in accordance with standard 61008-1.

The second unit 12 is for detecting DC fault currents as a function of the detected fault current F and, depending thereon, for providing a second control signal A2 for controlling the switching device 26 to open the DC+ line DC+ and the DC- line DC- and/or the further switching device 8 set up to open the phases L1, L2, L3 and the neutral conductor N.

The second unit 12 is preferably set up to connect a direct current detection device, preferably a residual direct current detection device according to the IEC 62955 standard, particularly preferably a residual direct current monitoring device according to the IEC 62955 standard emulate.

The charging station 1 can also comprise a module (not shown) which integrates the first unit 11 and the second unit 12 and which is adapted to a type B residual current circuit breaker, in particular according to standard EN 610081-1 and/or according to the standard EN 62423, to train or simulate appropriate error protection. The module can also be designed as part of the control device 13 .

Furthermore, the control device 13 is set up to send a third control signal A3 to control the switching device 26 to open the DC+ line DC+ and the DC- line DC- and/or to control the further switching device 8 to open the phases L1, L2, L3 and the neutral conductor N to provide. The control device 13 generates the third control signal A3 in particular depending on a vehicle authentication and/or vehicle verification and/or user authentication and/or user verification, depending on of overcurrent monitoring and/or depending on correct connection of the charging cable 5 to the electric vehicle 3 and/or to the charging station 1.

The charging station 1 also includes a control circuit 14. The control circuit 14 is set up to control the switching device 26 and/or the further switching device 8, if at least one of the control signals A1, A2, A3 is provided, by means of an opening signal O in such a way that the DC+ -Line DC+ and the DC- line DC- and/or the phases L1, L2, L3 and the neutral conductor N of the charging station 1 opens. In other words, the control circuit 14 then controls the switching device 26 to open the DC+ and DC- lines and/or the further switching device 8 to open the phases L1, L2, L3 and the neutral conductor N when one or more of the control signals A1, A2 , A3 is provided or set. For this purpose, for example, the drive circuit 14 comprises a WIRED-OR operation which ORs the first drive signal A1, the second drive signal A2 and the third drive signal A3. Furthermore, the drive circuit 14 is the 4 set up, in particular, to control not only the switching device 26 but also the further switching device 8, if at least one of the control signals A1, A2, A3 is provided, by means of the opening signal O in such a way that these phases L1, L2, L3 and the neutral conductor N in the charging station 1 opens. This increases the security of the charging station 1 .

In addition, the illustrated 4 that a charge pilot signal CP can be transmitted between the control device 13 of the charging station 1 via the charging cable 5 with the electric vehicle 3 .

Furthermore, the charging station 1 of 4 a communication module 19. The communication module 19 is set up to negotiate a charging plan with charging electronics of the electric vehicle 3 coupled to the charging station 1 in accordance with high-level communication, in particular the ISO 15118 standard.

In addition, the charging station 1 includes the 4 a communication interface 20. The communication interface 20 is set up to exchange data with a terminal device of the user and/or a server which manages the charging station 1 in particular. The user can, in particular, authenticate and/or verify himself via the terminal device, but also in particular authenticate and/or verify the vehicle.

The communication module 19 and the communication interface 20 are preferably designed as a single component which can perform both tasks.

Furthermore, the charging station 1 of 4 a user interface 21 for input from the user and/or for output to the user. For example, the user interface 21 includes a touch screen. In addition, at least one power pack 22 is provided, which is set up to convert an AC voltage provided via the phases L1, L2, L3 into a predetermined DC voltage for the control device 13 and/or the other components of the charging station 1.

Furthermore, the charging cable 5 is the 4 an insulation breakage sensor 18 assigned. The insulation rupture sensor 18 is suitable for providing an insulation rupture sensor signal IS, which is indicative of an insulation rupture in the charging cable 5, the charging connector 17 and/or the housing 1. In order to provide the broken insulation sensor signal IS, the broken insulation sensor 18 carries out, for example, an impedance measurement, a capacitive measurement, a voltage measurement, a current measurement, a power measurement and/or an inductive measurement. An example of such an insulation break is a break in the insulating sheath of the charging cable 5.

Furthermore, the charging station 1 has the 4 an evaluation unit 23 which is set up to evaluate the insulation breakage sensor signal IS that is provided in order to determine an insulation breakage IB of the charging cable 5 of the charging plug 17 and/or of the housing 1. As an alternative or in addition, further insulation breakage sensors can be provided (not shown), for example assigned to the charging plug 17 and/or the housing of the charging station 1.

The control device 13 is then set up to provide the third control signal A3 as a function of a determined insulation breakage IB. In other words, if an insulation breakage IB is detected, the third control signal A3 is provided or set and consequently the switching device 26 and/or the further switching device 8 opens.

Furthermore, the charging station 1 preferably has an electromechanical system (not shown) for mechanically displaying the switching position of the further switching device 8 . The electromechanics include a shutter controlled via an electrical coupling of the feedback contacts of the further switching device 8, which follows the switching position of the further switching device 8, and a visual display device controlled by the shutter for displaying the switching position of the further switching device 8. The visual display device includes, for example, two LEDs that light up green and red. The bezel always covers one of the two LEDs, while the LED not covered by the bezel is visible to the user. Due to the electrical coupling of the panel with the feedback contacts of the additional switching device 8, the panel always follows the switching position of the additional switching device 8. The panel thereby controls the visual display device in such a way that it shows the user the switching position of the additional switching device 8 using the colors red and green .

The electromechanics are preferably coupled to an energy store in such a way that the electromechanics can maintain the display of the switching position of the further switching device 8 for a predetermined time even when the charging station 1 is in a de-energized state.

In addition, the charging station has 1 of the 4 a control unit 28 coupled to the control device 13, which is set up to control the AC/DC converter 15 by means of a control signal C1 and to control the DC/DC converter 25 by means of a control signal C2. For example, the control signals C1 and C2 can be used to switch off the AC/DC converter 15 and the DC/DC converter 25 when an opening signal O is set.

Furthermore, the control unit 28 is preferably set up to control the AC/DC converter 15 with a DC charging voltage of no more than 600 V in such a way that the DC+ line DC+ coupled to the inner conductor DC+ of the charging cable 5 carries a first direct voltage and the the DC line coupled to the outer conductor DC of the charging cable 5 carries a second direct voltage, the first direct voltage and the second direct voltage having different signs and the same amounts.

Furthermore, the control unit 28 is preferably set up to control the AC/DC converter 15 at a DC charging voltage of more than 600 V in such a way that the DC line coupled to the outer conductor DC of the charging cable 5 generates a third DC voltage with a negative sign and an amount of at most 300 V and the DC+ line DC+ coupled to the inner conductor DC+ of the charging cable 5 carries a fourth direct voltage with a positive sign and an amount which corresponds to a difference between the DC voltage and the third direct voltage.

Furthermore, the charging station 1 has an intermediate circuit coupled between the AC/DC converter 15 and the DC/DC converter 25 with an intermediate circuit potential ZP and a setting unit 29. The setting unit 29 sets the intermediate potential ZP of the intermediate circuit in such a way that the third DC voltage and the fourth DC voltage are symmetrical to the set intermediate potential ZP. For this purpose, the setting unit 29 preferably has a voltage regulator which is set up to regulate the intermediate potential ZP in such a way that it lies symmetrically between the third direct voltage and the fourth direct voltage.

5 shows a third alternative embodiment of a charging station 1 to the second embodiment of FIG 4 . The third embodiment of the 5 differs from the second embodiment of the 4 to the effect that different, dedicated control signals T1 and T2 are used to control the switching device 26 and the additional switching device 8, namely a first control signal T1 for the switching device 26 and a second control signal T2 for the additional control device 8.

The switching device 26 is preferably designed as a first electrically controllable power switching element, and the further switching device 8 is preferably designed as a second controllable power switching element. The first power switching element is an electromagnetically switched power switching element, each of the power switching elements 8, 26 having a non-conductive switching state in which no current can flow and a conducting switching state in which current can flow. In this case, each of the power switching elements 8 , 26 is set up to interrupt a flow of energy through the charging station 1 to the energy store 2 of the electric vehicle 3 .

1. a) einen elektromagnetischen Antrieb des ersten Leistungsschaltelements 26 mittels eines ersten Ansteuersignals mit einer Anziehspannung anzusteuern, um das erste Leistungsschaltelement 26 von dem nicht-leitenden Schaltzustand in den leitenden Schaltzustand zu verbringen,
2. b) den elektromagnetischen Antrieb des ersten Leistungsschaltelements 26 mittels des ersten Ansteuersignals mit einer gegenüber der Anziehspannung verringerten Haltespannung anzusteuern, nachdem das erste Leistungsschaltelement 26 in dem leitenden Schaltzustand ist, und
3. c) das zweite Leistungsschaltelement 8 mittels eines zweiten Ansteuersignals anzusteuern, um das zweite Leistungsschaltelement 8 von dem nicht-leitenden Schaltzustand in den leitenden Schaltzustand zu verbringen, nachdem ein Stromfluss durch den elektromagnetischen Antrieb des ersten Leistungsschaltelements 26 betraglich einen bestimmten Schwellwert erreicht oder unterschreitet.

The control device 13 is set up to

1. a) to control an electromagnetic drive of the first power switching element 26 by means of a first control signal with a pick-up voltage in order to bring the first power switching element 26 from the non-conductive switching state to the conducting switching state,
2. b) to control the electromagnetic drive of the first power switching element 26 by means of the first control signal with a holding voltage that is lower than the pull-in voltage after the first power switching element 26 is in the conductive switching state, and
3. c) to drive the second power switching element 8 by means of a second drive signal in order to switch the second power switching element 8 from the non-conducting switching state to the conducting state to spend the switching state after a current flow through the electromagnetic drive of the first power switching element 26 has reached or fallen below a specific threshold value.

This functionality can also be taken over by the control device 14 . In embodiments, the control device 14 can also be designed as part of the control device 13 .
As the 4 and 5 show, the charging station is preferably transformerless and can therefore preferably be referred to as a transformerless charging station 1.

In addition, the 6 a schematic view of an embodiment of a method for operating a charging station 1 for charging an energy store 2 of an electric vehicle 3 with electrical energy by means of a multi-phase network 4 that can be coupled to the charging station 1.

The charging station 1 is, for example, as in FIG 4 or in the 5 shown executed. The procedure of 6 comprises steps S10, S20, S31 and S32.

In step S10, a current DC charging voltage negotiated between the charging station 1 and the electric vehicle 3 for charging the electric vehicle 3 is determined.

In step S20, it is determined whether the currently determined DC charging voltage is less than 600 V. If the current DC charging voltage determined is less than 600 V, step S31 is applied next. However, if the determined DC charging voltage is greater than or equal to 600 V, step S32 is applied.

In step S31, the AC/DC converter 15 is controlled in such a way that the DC+ line DC+ coupled to the inner conductor DCI of the charging cable 5 or the coupled DC- line DC- carries a first direct voltage and that coupled to the outer conductor DCA of the charging cable 5 DC- line DC- or coupled DC+ line DC+ carries a second direct voltage, the first direct voltage and the second direct voltage having different signs and the same amounts.

In contrast, in step S32, if the current DC charging voltage determined is greater than or equal to 600 V, the AC/DC converter 15 is controlled in such a way that the DC line coupled to the outer conductor DCA of the charging cable 5 is DC or 5th coupled DC+ line DC+ carries a third direct voltage of a maximum amount of 300 V, and the DC+ line DC+ coupled to the inner conductor DCI of the charging cable 5 or coupled DC- line DC- carries a fourth direct voltage of an amount equal to the difference between the DC -charging voltage and the third direct voltage, leads, the third direct voltage and the fourth direct voltage having different signs and different magnitudes..

In the procedure after 6 the DC voltage carried on the outer conductor DCA is limited to a maximum of 300 V. In particular, this is not life-threatening. For example, if the DC charging voltage negotiated between the charging station 1 and the electric vehicle 3 is 800 V, then the third DC voltage can be −300 V, whereas the fourth DC voltage can be +500 V.

Although the present invention has been described on the basis of embodiments, it can be modified in many ways.

Reference List

1

charging station

2

energy storage

3

electric vehicle

4

multiphase subscriber network

5

charging cable

6

grid connection point

7

multi-phase power supply network

8th

switching device

9

residual current sensor

10a

terminal block

10b

terminal block

10c

terminal block

10d

terminal block

10e

terminal block

11

first unit

12

second unit

13

control device

14

control circuit

15

AC/DC converter

16

terminal strip

17

charging plug

18

Insulation break sensor

19

communication module

20

communication interface

21

user interface

22

power adapter

23

Insulation break evaluation unit

24

EMC filter

25

DC/DC converter

26

switching device

27

EMC filter

28

control unit

29

adjustment unit

A1

first control signal

A2

second control signal

A3

third control signal

AR

outdoor space

C1

control signal

C2

control signal

CP

Charge Pilot signal line

DC+

DC+ line

DC

DC line

DCI

inner conductor

DCA

outer conductor

f

residual current

IB

insulation rupture

IR

inner space

IS

Insulation break sensor signal

K1

layer of plastic

K2

layer of plastic

L1

phase

L2

phase

L3

phase

N

neutral wire

O

opening signal

PE

PE conductor

T

Temperature signal line

T1

control signal

T2

control signal

S10

process step

S20

process step

S31

process step

S32

process step

ZP

intermediate potential

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 10151153 A1 [0004]
• EP 3175529 B1 [0005]
• US20190143822A1 [0005]
• US9425641B2 [0005]
• US 9789774 B2 [0005]
• DE 102021106275 [0006]
• DE 1020211082331 [0006]

Claims (19)

Charging cable (5) for a charging station (1) for charging an energy store (2) of an electric vehicle (3) with a DC charging voltage, in particular of at least 600 V, wherein the charging cable (5) is a coaxial cable with an inner conductor (DCI) and a hollow-cylindrical outer conductor (DCA), wherein the inner conductor (DCI) is designed for a first nominal voltage and the outer conductor (DCA) for a second nominal voltage, wherein the quotient of the first nominal voltage and the second nominal voltage is in a range between 1.1 and 5, preferably in a range between 1.3 and 4, more preferably in a range between 1.6 and 3. charging cable claim 1 , characterized in that the inner conductor (DCI) and the hollow-cylindrical outer conductor (DCA) are embedded in an insulating plastic (K1, K2), with an additional PE conductor (PE) and a charge pilot signal line (CP) in the Plastic (K1, K2) are embedded. charging cable claim 2 , characterized in that the charging cable (5) has an interior (IR) and an exterior (AR), wherein the hollow-cylindrical outer conductor (DCA) delimits the interior (IR), wherein in the interior (IR) a first layer (K1) of the plastic separates the inner conductor (DCI) and the outer conductor (DCA), with the PE conductor (PE) and the charge pilot signal line (CP) being embedded in the outer space (AR) in a second layer (K2) of the plastic . charging cable claim 3 , characterized in that the PE conductor (PE) is designed as a hollow-cylindrical coaxial conductor which encloses the outer conductor (DCA) and is embedded in the second layer (K2) of the plastic. charging cable claim 4 , characterized in that the charge pilot signal line (CP) and a plurality of temperature signal lines (T) are embedded outside of the PE conductor (PE) in the second layer (K2) of the plastic. charging cable according to one of the Claims 1 until 5 , characterized in that the hollow-cylindrical outer conductor (DCA) is designed as a mesh made of a plurality of conductors, in particular wires, the mesh being preferably set up to contract when the charging cable (5) is stretched. Transformerless charging station (1) for charging an energy store (2) of an electric vehicle (3) with electrical energy by means of a multi-phase network (4) that can be coupled to the charging station (1), with an AC/DC converter (15) for converting one of the polyphase grid (4) via the phases (L1, L2, L3) into a direct current provided by means of a DC+ line (DC+) and a DC- line (DC-), a control device (13) for controlling components of the Charging station (1) comprising the AC / DC converter (15), and a charging cable (5) according to one of Claims 1 until 6 . charging station after claim 7 , characterized by a control unit (28) which is set up to control the AC/DC converter (15) at a DC charging voltage of at most 600 V in such a way that the DC+ coupled to the inner conductor (DCI) of the charging cable (5). line (DC+) or DC- line (DC-) carries a first direct voltage and the DC- line (DC-) or DC+ line (DC+) coupled to the outer conductor (DCA) of the charging cable (5) carries a second direct voltage leads, the first direct voltage and the second direct voltage having different signs and the same amounts, and with a DC charging voltage of more than 600 V to control the AC/DC converter (15) in such a way that the outer conductor (DCA) of the charging cable (5) coupled DC- line (DC-) or coupled DC+ line (DC+) carries a third DC voltage with a maximum amount of 300 V and the DC+ line (DC+ ) or coupled DC--line (DC-) a fourth DC voltage with a Be carry, which corresponds to a difference in magnitude between the DC charging voltage and the third DC voltage, the third DC voltage and the fourth DC voltage having different signs and different magnitudes. charging station after claim 7 or 8th , characterized by a DC/DC converter (25) connected downstream of the AC/DC converter (15), an intermediate circuit coupled between the AC/DC converter (15) and the DC/DC converter (25) and having an intermediate potential ( ZP) and a setting unit (29) for setting the intermediate potential (ZP) of the intermediate circuit in such a way that the third direct voltage and the fourth direct voltage are symmetrical to the set intermediate potential (ZP). charging station after claim 9 , characterized in that the adjustment unit (29) has a voltage regulator which is set up to regulate the intermediate potential (ZP) in such a way that it lies symmetrically between the third direct voltage and the fourth direct voltage. charging station after one of the Claims 7 until 10 , characterized by a fault current sensor (9) assigned to the phases (L1, L2, L3) and the neutral conductor (N), which is set up to detect a fault current (F) that varies over time with a direct current component and an alternating current component, a switching device (26) which, for opening and closing of the DC+ line (DC+) and the DC- line (DC-) of the charging station (1), a first unit (11) which is designed to detect sinusoidal alternating residual currents and pulsating direct residual currents as a function of the detected residual current ( F) and is set up depending on this for providing a first control signal (A1) for controlling the switching device (26) for opening the DC+ line (DC+) and the DC- line (DC-), and a second unit (12), which for detecting DC fault currents as a function of the detected fault current (F) and, depending thereon, for providing a second drive signal (A2) for driving the switching device (26) to open DC+ line (DC+) and the DC- line (DC-), the control device (13) for providing a third control signal (A3) for controlling the switching device (26) for opening the DC+ line (DC+) and the DC line (DC-) is set up. charging station after one of the Claims 7 until 10 , characterized by a fault current sensor (9) assigned to the phases (L1, L2, L3) and the neutral conductor (N), which is set up to detect a fault current (F) that varies over time with a direct current component and an alternating current component, a further switching device (8) which is set up to open and close the phases (L1, L2, L3) and the neutral conductor (N) of the charging station (1), a first unit (11) which is used to detect sinusoidal alternating fault currents and pulsating direct fault currents depending on the detected fault current (F ) and is set up depending on this for providing a first control signal (A1) for controlling the further switching device (8) for opening the phases (L1, L2, L3) and the neutral conductor (N), and a second unit (12) which for Detecting DC fault currents as a function of the detected fault current (F) and depending thereon for providing a second drive signal (A2) for driving the further Sch old device (8) for opening phases (L1, L2, L3) and the neutral conductor (N) is set up, the control device (13) for providing a third control signal (A3) for controlling the further switching device (8) for opening the phases ( L1, L2, L3) and the neutral conductor (N) is set up. charging station after one of the Claims 7 until 12 , characterized by an insulation rupture sensor (18) assigned to the charging cable (5) and/or the housing of the charging station (1) for providing an insulation rupture sensor signal (IS) which is indicative of an insulation rupture in the charging cable (5) and/or the housing of the charging station (1), and an evaluation unit (23) which is set up to use the insulation breakage sensor signal (IS) provided to determine an insulation breakage (IB) of the charging cable (5) and/or the housing of the charging station (1) evaluate, wherein the control device (13) is set up to provide the third control signal (A3) as a function of a determined insulation breakage (IB). charging station after one of the Claims 7 until 13 , characterized in that in addition to the switching device (26) in the DC circuit, a further switching device (8) is provided in the AC circuit, which is used to open and close the phases (L1, L2, L3) and the neutral conductor (N) of Charging station (1) is set up. charging station after Claim 14 , characterized in that the switching device (26) is designed as a first electrically controllable power switching element and the further switching device (8) is designed as a second controllable power switching element, the first power switching element (26) being an electromagnetically switching power switching element, each of the power switching elements (8, 26) has a non-conductive switching state in which no current can flow and a conductive switching state in which current can flow, each of the power switching elements (8, 26) being used to interrupt a flow of energy through the charging station (1) to the energy store (2) of the electric vehicle (3), the control device (13) being set up to: a) control an electromagnetic drive of the first power switching element (26) by means of a first control signal (T1) with a pull-in voltage in order to activate the first Power switching element (26) from the non-conductive Sc to spend the halt state in the conducting switching state, b) to control the electromagnetic drive of the first power switching element (26) by means of the first control signal (T1) with a holding voltage that is lower than the pull-in voltage after the first power switching element (26) is in the conductive switching state, and c) the second power switching element (8) by means a second drive signal (T2) in order to bring the second power switching element (8) from the non-conductive switching state to the conducting switching state after a current flow through the electromagnetic drive of the first power switching element (26) has reached or fallen below a specific threshold value. charging station after one of the Claims 7 until 15 , characterized in that the housing of the charging station (1) and the charging cable (5) including its charging plug (17) are double insulated. System with a plurality N of charging stations (1), wherein the respective charging station (1) according to one of Claims 7 until 16 is trained. system after Claim 17 , characterized in that the N charging stations (1) are connected by means of a star connection to a single circuit breaker, which is coupled to the grid connection point (6). Method for operating a charging station (1) for charging an energy store (2) of an electric vehicle (3) with electrical energy by means of a multi-phase network (4) which can be coupled to the charging station (1) and which has an AC/DC converter (15) for conversion an AC voltage provided by the multiphase network (4) via the phases (L1, L2, L3) into a DC voltage provided by means of a DC+ line (DC+) and a DC- line (DC-), a control device (13) for controlling of components of the charging station (1) comprising the AC / DC converter (15) and a charging cable (5) according to one of Claims 1 until 6 has, with the steps: a) determining (S10) a current DC charging voltage for charging the electric vehicle (3) coupled to the charging station (1), b) determining (S20) whether the determined current DC charging voltage is less than 600 V c1) if the current DC charging voltage determined is less than 600 V, driving (S31) the AC/DC converter (15) in such a way that the DC+ line ( DC+) or DC- line (DC-) carries a first direct voltage and the DC- line (DC-) or DC+ line (DC+) coupled to the outer conductor (DCA) of the charging cable (5) carries a second direct voltage, whereby the first DC voltage and the second DC voltage have different signs and the same amounts, and c2) if the determined current DC charging voltage is greater than or equal to 600 V, controlling (S32) the AC/DC converter (15) in such a way that the DC- line (DC-) or DC+ line (DC+) coupled to the outer conductor (DCI) of the charging cable (5) a third direct voltage with a maximum magnitude of 300 V and the DC+ line (DC+) or DC- line (DC-) coupled to the inner conductor (DCI) of the charging cable (5) carries a fourth direct voltage with a magnitude which is a difference between the DC charging voltage and the third DC voltage, the third DC voltage and the fourth DC voltage having different signs and different magnitudes.

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