WO2019105943A1 - On-board vehicle power system having an inverter, energy store, electric machine and ac transmission connection - Google Patents

Abstract

An on-board vehicle power system is equipped with an inverter (WR), an electric energy store (ES), an electric machine (EM) and a single-phase AC transmission connection (AC). The inverter (WR) has a first (S1) and a second side (S2) and is configured to transmit power between these two sides. The first side (S1) of the inverter (WR) is connected to the energy store (ES) via a positive and a negative input current connection (EA1, EA2) of the inverter (WR). The second side (S2) of the inverter (WR) is connected to the electric machine (EM) via at least two phase current connections (PS1, PS2, PS3) of the inverter (WR). The inverter (WR) includes at least two H-bridges (HB1, HB2, HB3). Each of the H-bridges (HB1, HB2, HB3) bypasses the two sides (S1, S2) of the inverter (WR). The AC transmission connection (AC) is connected to the second side (S2) of the inverter (WR).

Description

description

Vehicle electrical system with inverter, energy storage,

electric machine and AC transmission connection

Motor vehicles with an electric drive, i. Electric vehicles and hybrid vehicles, include an electrical energy storage for supplying the electric drive. Electric vehicles and plug-in hybrids are equipped with a connection that can be used to transfer energy from a stationary electrical supply network (local or public) to recharge the energy storage device. Optionally, the vehicles are also equipped to feed electrical energy back to the utility grid.

To transfer electrical energy between the grid and the vehicle power electronic components are neces sary, especially for controlling the energy transfer.

It is an object of the invention to provide a way by which the cost of such components can be reduced.

This object is solved by the subject matter of the independent claims. Further advantages, features, embodiments and features will become apparent from the dependent claims and from this description and the figures.

It is envisaged that for the transmission of an alternating current to or from the vehicle electrical system (one described above

Motor vehicle) components of an inverter can be used. The inverter has a first and a second side. The inverter is set up to transfer power between these pages, in particular bidirectionally. The first side is connected to a (DC) energy storage, in particular via a positive and a negative input power connection of the inverter. The first page can be considered as the DC side of the inverter. The second side of the inverter is with an electric Machine or their phases connected, in particular via Pha senstromanschlüsse the inverter. The inverter has at least 2 H-bridges bridging the two sides (ie the first and the second side of the inverter). A part of each bridge can be assigned to the first page and a part of each bridge can be assigned to the second page. The H-bridge connects in series the two sides with each other. In particular, each H-bridge can each one

Have transverse branch for each of the two sides. This shunt arm can also be called an arm. Each shunt branch or arm connects by means of (controllable) switch the two input current connections. A connection between the arms or transverse branches (in particular comprising a series inductance) connects the two sides of the inverter.

An AC transmission port is provided. This is designed in a single phase. The change

Strom-Übertragungsungsanschluss is designed to be accessible from the outside. The AC transmission terminal is thus arranged to transfer energy (in particular, a single-phase AC power source) between an external AC electric power source, on the one hand, and the vehicle electrical system or the power storage, on the other hand. The external electrical AC power source is outside the vehicle electrical system and in particular not part of the electrical system. The change

Power transmission terminal configured to be connected to the external AC power source, either by cable, such as in electromechanical manner, for example, as a fastex connection, or wirelessly, for example, inductively. The alternating current transmission terminal is accessible for power transmission from outside. The AC transmission terminal may be formed as a charging terminal or feed terminal, wherein the AC transmission terminal can only operate unidirectionally, such as for transmitting energy in the vehicle onboard power supply, or bidirectionally next to the charging or feeding can also be designed to feed back in the sense a charging and regenerative connection. These functions are defined in particular by the inverter and its controller. The AC transmission connection can be designed as a connection plug-in element, which also as

Plug-in connector is called. The change

In particular, a current transmission connection comprises a socket or a plug. The AC transmission port includes at least two contacts, one of the contacts being a phase connection and another one of the contacts

Neutral connection is. The contacts may additionally have a protective conductor contact. The contacts are accessible from the outside and can be protected by a flap. The contacts are directed outwards (relative to the outer skin of the vehicle in which the vehicle electrical system is located). The AC transmission connection is preferably designed as an insert, which can be embedded in an outer skin of a vehicle in order to be able to produce a plug connection with the alternating current transmission connection from the outside. The examples cited are electromechanical embodiments of the AC transmission connection. Alternatively, the AC transmission terminal is adapted for inductive power transmission. The alternating current transmission connection can thus also be designed as a (single-phase) secondary coil which is set up to inductively exchange energy with a primary coil (for example a stationary one). It can be provided a capacitor, which forms a resonant circuit with the secondary därspule to inductively replace energy inductively. The secondary coil may be arranged to be arranged on a vehicle floor or on a vehicle front. As with the electromechanical design, the inductive version of the AC transmission port is externally accessible and configured to transfer energy.

The AC transmission terminal is connected to the second side of the inverter, in particular to the second side or to one of the sections of H-bridges associated with the second side. The AC transmission terminal may be connected to one of the phase current terminals (the second side) of the inverter or to one of the shunt branches of at least two H-bridges, the shunt branches being in the second side of the inverter. Specifically, the AC transmission terminal may be connected to one end of one of the inductances of the bridges, referring to the sides of the inductances that are in the second side or that are connected to one arm, that of the second one Page is assigned (and is also there).

The AC transmission terminal is further connected to one of the input power terminals of the inverter, in particular to the negative input power terminal. In other words, the AC transmission terminal is further connected to a DC potential (Versorgungspoten tial) or a DC busbar of the inverter. This applies in particular to a neutral conductor or return conductor and in particular to the neutral conductor connection of the alternating current transmission connection. The phase connection or the phase potential of the AC transmission connection is connected to the second side of the inverter. Here, the phase connection or the phase potential of the change

Strom-Übertragungsungsanschlusses be connected to one of the phase current connections, preferably in a direct manner. Furthermore, the phase connection or the phase potential of the Wech selstrom transmission terminal may be connected to several of the phase current connections, preferably in a direct manner, wherein a switch can be used to the power connections phase bundled with the change

current transmission connection, in particular with the (preferably single) phase of the change

power transmission connection. In the latter case, phase connections or H-bridges are used bundled to power between the AC transmission port and the

Inverter to transfer. Alternatively, it can be connected to one of the phase current connections via the electric machine (in particular via one or more winding (s) or phase (s) of the electrical machine). In addition, the phase connection or the phase potential of the change

current transmission terminal to be connected to a plurality, all or a subset of the phase current terminals. in the the latter case windings are bundled used to transfer power between the AC transmission port and the inverter. In particular, the term "bundled" can be understood as "connected to one another at one side (parallel)" so as to represent the electrical equivalent of the bundling.

The H-bridges of the inverter can each have two arms. These connect the positive input power connection (corresponding to a positive DC potential of the inverter) to the negative input power connection (corresponding to a negative DC potential of the inverter) by means of two serial semiconductor switches. The two serial semiconductor switches are thus connected in parallel with the two input power connections. The semiconductor switches of each arm are connected at connection points. The two connection points of each H-bridge are connected to each other by means of an inductance.

The AC transmission port (such as a

Plug-in connector or a vehicle-side direction ago for inductive energy transfer) may be connected to the electrical machine facing (second) side of the Wech selrichter, in particular to at least one phase current connection of the inverter or to another connection point, located in the second Side of the inverter.

A phase potential or a phase of change

current transfer connection and a neutral potential or neutral potential connection of the change

Power transmission connections are connected to the inverter. The phase of the AC transmission terminal is connected to one or more phase current terminals of the inverter Wech, either directly or indirectly via one or more windings of the electric machine (in short, in directly on the electric machine). When connecting across multiple phases of the electrical machine, a switch can be used to bundle the phases. The several Windings are then bundled with the phase of the alternating current transmission connection. The neutral of the AC transmission port is preferably connected to one of the input power terminals (or to a DC or supply potential) of the inverter, in particular to a negative input power terminal or ground input power terminal.

The AC transmission terminal may be directly connected to one or more phase current terminals of the inverter, or may be connected to the inverter via an electric machine (the vehicle electric drive) connected to the phase power terminals. The connection between change

current transmission connection and the inverter or its second side, in particular between change

Power transmission connection and (at least one) phase power connection, can thus be provided directly or indirectly via the electric machine.

As a result, a vehicle can be charged directly from a (single-phase) AC power supply or can deliver directly into this energy. A stationary rectifier is not necessary. Rather, its function is realized by the inverter. The already existing power electronics in the form of the inverter, which in particular provides the phase currents for the electric machine, is also used to control the power (in particular of the current and / or the voltage), which is via the change

current transmission connection is transmitted. It is in particular special no further voltage converter to adapt to the voltage of the energy storage essential.

The inverter includes H-bridge circuits. These are connected between the electrical energy storage and the phase power connections. This allows operation of the inverter for conversion between the DC voltage of the energy storage and the phase voltages of the phase terminals (ie the electric machine), such as in ferry mode. From this Operating mode, the term "inverter" is also derived, with other modes, such as the rectification of Wech sel-charging voltage for feeding into the energy storage, are also possible, even if they are not incorporated into the concept formation.The H-bridges also allow the conversion between The AC voltage at the AC transmission terminal and the DC voltage of the energy storage device This applies in particular to the type of current and the current level.

As described, the vehicle electrical system described here is equipped with an inverter, an electrical energy store, an electric machine and an AC transmission terminal. The inverter includes (control signal controllable) semiconductor power switches. The topology of the inverter and its connection within the vehicle electrical system is shown below. The electric

Energy storage is in particular an accumulator, example, a lithium-based accumulator. The electrical energy store may be a traction accumulator. The

Energy storage device may have a nominal voltage of 40-60 V, in particular of 48 V, and may in particular have a nominal voltage of more than 100 volts, in particular of at least 200 or 300 V, for example 350-420 V. The energy store can thus be a high-voltage accumulator. The electric machine is in particular a three-phase machine. The electric machine can be a foreign-excited or permanently excited electric machine. It can also be used a single-phase machine; In this case, the AC transmission connection can be connected to the inverter in a single phase via the electrical machine (and thus indirectly).

The AC transmission port may include a (single-phase) plug-in inlet, ie a (single-phase) electromechanical plug-in connector that can be mounted in the outer skin of a vehicle. The AC transmission terminal is set to be connected to a charging plug (or general: connector). The inverter is controllable or includes controllable H-bridges. The inverter has a positive input power connection and a negative input power connection. The term input power connection results from the inverter mode in which the inverter receives power from the energy storage. The input current connections correspond to the respective supply potential or the (two) DC voltage busbars of the inverter. In inverter mode, the inverter receives power through the input power connector, so in this mode, this connector serves as the inverter input. In charging mode, the same connections serve to deliver power to the energy storage, ie as the output of the inverter.

The input power connections are connected to the energy storage. It may be connected in parallel to the energy storage or parallel to the input terminals of the inverter, a DC link capacitor.

The inverter has phase current connections connected to the electric machine, preferably at least two. In particular, the inverter has phase current connections in a number that corresponds to the number of phases of the electrical machine. Each of the phase current connections can be connected to a separate phase of the electrical machine. For example, the inverter has three (or six) phase current terminals each connected to one of three (or six) phases of the electric machine.

The inverter has a first side and a second side. The inverter is set up to transfer power between these pages. The first side of the inverter is connected to the energy storage device, in particular via a positive and a negative input current connection of the inverter. The second side of the inverter is connected to the electrical machine, in particular over at least two phase current terminals of the inverter. The inverter has at least two H-bridges. The H-bridges bridge the two sides. One section of each H-bridge (especially one arm of both arms) is part of the first side and another section of each H-bridge (in particular the other of the two arms) is part of the second side. The H-bridges are each connected between the input power connections and the phase current connections. The H-bridges are connected in series between the input power terminals and the phase current terminals. The H-bridges are connected in parallel (at least with regard to the input current connections). The H-bridges are individually connected to individual phases of the electrical machine.

Each H-bridge has two arms. A first of these arms (located on the first page) connects the two input power connections. A second of these arms (located in the second side) connects an input power connection (especially the negative ones) and a phase current connection. Each arm comprises two switching elements, which are connected to each other via a connection point. The two connection points of each H-bridge (i.e., the connection point of one arm and the connection point of the other arm of the same H-bridge) are connected to each other via an inductor.

The switching elements, in particular semiconductor switches, of each arm are connected to one another at connection points. The two connection points of each H-bridge are connected to each other by means of an inductance. The inductance is designed in particular as a discrete component, for example as a coil with a core. The inductor has a first terminal or a first side that belongs to the first side. The inductor has a second terminal and a second side, which belongs to the second side. The first terminal of the inductance is connected to a connection point of an arm of the first side. The second terminal of the inductor is connected to a connection point of an arm of the second side. This applies in particular to all H-bridges of the inverter. As mentioned, the H-bridges of the inverter can each have two arms. These connect the positive input current connection to the negative input current connection by means of two serial semiconductor switches. The semiconductor switches are preferably transistors, in particular field-effect or bipolar transistors, for example MOSFETs or IGBTs.

Each phase current connection may be connected via a capacitor to an input power connection (in particular to the negative input power connection). In other words, for each H-bridge, a capacitor may be connected in parallel with the second arm (i.e., arm of the second side of the inverter).

It is envisaged that the (single-phase) change

power transmission connection is connected to the inverter, in particular on the second side of the change

power transmission connection. The change

Current transfer terminal is configured single-phase and thus includes, for example, a phase conductor or phase contact on the one hand and a neutral conductor or Neutrallei terkontakt on the other. The change

In particular, current transmission connection is a grounded or ungrounded single-phase AC connection, for example designed as a safety socket (suitable for the CEE 7/4 standard), or as a socket according to the NEMA 1-15, 5-15, CEE 7/16, 7/17 standard, BS 546, CEE 7/5, CEE 7/7, SI-32, AS3112, SEV 1011, DS 60884-2-D1, CEI 23-50 or IEC 60906-1). The connection between the AC transmission port and the inverter (or its second side) may be single-phase, or multiple phases of the electric machine may be used in a cluster to represent the connection. The second side of the inverter preferably has a number of phases (corresponding to the number of phase terminals of the inverter or the number of H-bridges in the inverter), which corresponds to the number of phases of the electric machine. The number of phases of the alternating current transmission connection or of the connection is, in particular, less than the number of phases of the second side of the inverter or in particular is less than the number of H-bridges of the inverter. By means of the AC transmission connection (or via the connection) power can be fed via the inverter in the electrical energy storage. In particular, the AC transmission port may be connected to one of the phase current ports (or bundled with several or all of them) in a direct or indirect manner.

In particular, the link between change

Current transfer connection and the inverter (or its second side) no voltage or current transformer. The connection between AC transmission port and

(At least one) phase current connection may include a filter and / or security elements such as a fuse and / or a circuit breaker.

The AC transmission port may be directly connected to one of the phase current ports (or bundled with several or with other components of the second side of the inverter). Further, the AC transmission port may be indirectly connected via the electric machine with one of the phase current terminals (or bundled with several of the Pha senstromanschlüsse or other components of the second side of the inverter). The AC power transmission connection can thus be connected directly or indirectly (namely, via the electric machine) to the inverter.

The term "directly connected" refers to a connection that does not include an electrical machine or windings of an electrical machine, so "directly connected" refers to a connection that has no circuit for voltage or current conversion. As a "directly connected" may be referred to a connection having a filter and / or security elements such as a fuse and / or a disconnecting switch can be referred to as "indirectly connected" a connection, which is an electrical machine or a windings of a Electric machine includes (about in Rei henschaltung). In the case of a direct connection, the voltage at the energy store can be connected to the alternating voltage at the changeover voltage. current transmission connection to be adjusted. In particular, no DC booster is necessary. In an indirect connection, AC charging and DC charging can be combined (at the same time). In particular, a match can be

power transmission terminal can be connected to (two) phase terminals of the inverter, whereby AC and DC charging can be performed (at the same time).

The AC transmission terminal or its phase may be connected directly to a phase current connection (or the bundled phase current terminals (or the inverter or its second side), wherein the neutral conductor may also be connected directly to one of the input current terminals of the inverter The inverter or the inverter or its second side may be connected to the electric machine via a circuit breaker This disconnector serves to disconnect the electrical machine from the inverter, in particular in the charging mode or in the regenerative mode.

Alternatively or in combination herewith, a circuit breaker may be provided which is provided between windings of the electric machine. The latter disconnector is used for controllable cancellation of the wiring configuration of the windings, in particular a star or Dreieckskonfigu ration, especially in the charging mode or in the regenerative mode. Therefore, a circuit breaker such as the latter may be provided between phase windings of the electric machine (in connections between the phase windings of the electric machine itself). The circuit breaker may be configured to connect the windings or their ends in a first state to a common neutral point of the electric machine, and in a second state, to preferentially separate the connection of the windings with one another.

Such a circuit breaker may be arranged to at least partially cancel a star connection (or triangular connection). The circuit breaker may be provided as a switch, which is at least one of the with the Wechsel- current transfer connection disconnects connected phase winding (the electric machine) from other phase windings. The switch may also be provided to disconnect all phase windings, a subgroup of the phase windings or a phase winding from a star point of the electrical machine or to separate all phase windings from one another under control. The switch may also be used to selectively connect phase windings of the electrical machine to bundle them so that a plurality of phase windings of the electric machine are connected to the phase of the AC transmission terminal (for this purpose, another switch may be provided which controls the phase of the AC transmission connection controlled by the winding (s) of the electrical machine.

Preferably, the switch is arranged to separate only a part of the phase windings from a star point of the electric machine or only a part of the phase windings controlled from each other, while the other phase windings remain connected.

As mentioned, the AC transmission terminal may be connected directly (i.e., via the electric machine) to a phase current terminal or to multiple phase current terminals or to the inverter.

The AC transmission terminal may be connected to a switch with the electric machine or their windings. The switch is connected to connect the electrical machine or its windings in a first state with each other. In the first state, the windings are connected, for example, to a common neutral point of the electrical machine or the windings are connected in series with each other, i. provided in triangular configuration. In this switching state, the star configuration of the

electrical machine one end of the windings be mitei each other connected, i. the electric machine can be in star configuration. Furthermore, in this

Switching state, the windings are strung together in the sense of a triangle or delta configuration. In a second Switching state, the windings are connected to the AC power transmission connection. In the second

Switching state, one end of the windings is connected to the AC transmission port. The windings and the electric machine are connected in series between the inverter (i.e., its second side and the phase terminals) and the AC transmission terminal. The switch can have n-1 individual switching elements, where n is the number of phases or the number of windings of the electrical machine. A phase or a winding of the electrical machine can therefore be connected directly to the AC power transmission connection, wherein another or bundled all other phases or windings are connected via individual switching elements to the AC transmission port, in particular with the phase of the AC current -Übertragungsanschlusses. The switch is set up to dissolve the connections between the windings (such as the star point or the triangle configuration) in the second switching state and to connect the windings (one-sided) to the AC transmission connection.

The H-bridges of the inverter may each have an arm on the first and second sides of the inverter. These arms connect the positive input power connection to the negative input power connection via two serial solid state switches. Each arm preferably comprises two serial (controllable) semiconductor switches. Each arm is connected in parallel to the energy store or to the input power connections. The two semiconductor switches of each arm are connected via a connection point. The change

Current transmission terminal may be connected to a point of an arm lying on the second side or may be connected to the bundled (ie interconnected) connection points of those arms lying on the second side. In other words, the AC transmission terminal may be connected to the connection point or connection points of the arm or arms connected to the electric machine or at least one of the phase terminals. The one or more mentioned above Connection points are on the side of the inverter, which is the entge the power terminals or the energy storage is set entge. An additional circuit breaker (compare the circuit breaker T, T 'and the switch T''of Figures 1-3) is then not necessary and can be omitted or replaced by continuous connections.

The vehicle electrical system may further comprise a DC transmission port. This has a positive and a negative rail (or a negative and a positive connection point). The positive rail may be connected to one of the phase terminals, to multiple (and different) phase terminals, or to all phase terminals. In particular, when the positive rail is connected to a plurality of phase terminals or to all the phase terminals, a multi-phase circuit breaker may be provided between the DC current transmission terminal and the respective phase terminals. This can be closed (by means of a control unit) in the charging mode and in the regenerative mode and can be opened in the recuperation mode and in the inverter mode (in which the electric machine is supplied by the inverter) in order to provide the phase connections electrically separated. Furthermore, the positive rail can be connected via the electric machine to the inverter or its phase connections. There may be provided a selector switch which connects either the DC transmission port or the AC transmission port to the inverter (directly or via the electric machine). Further, a disconnect switch may be connected downstream of the DC transfer port and / or the AC transfer port, with a control unit controlling the same configured to disconnect the DC transfer port in an AC charging mode and in an AC regenerative mode, and a DC charging mode and disconnect the AC transmission port in a DC regenerative mode. Furthermore, both transmission connections can be used simultaneously in order to transmit energy, wherein in particular one of the two transmission connections can be connected to at least one of the phase connections of the exchange system. is connected to the inverter and the other transmission terminal is connected to at least one of the connection points of the inverter.

The negative rail may be connected to another of the phase terminals (if not connected to the positive rail) or to the negative input terminal.

It may be a control unit (such as the mentioned control unit) may be provided, which drives the inverter. The control unit is drivingly connected to the inverter. In an inverter mode of the control unit, the inverter is driven to generate from the DC voltage of the energy giespeichers phase voltages applied to the Pha senanschlüssen. In an (optional) recuperation mode, the control unit controls the inverter to generate a charging voltage at the energy store from the phase voltages at the phase terminals. In a (alternating current) charging mode, the control unit controls the inverter from the voltage applied to the change

power transmission terminal is present to generate a charging voltage to the energy storage. In this case, the AC voltage applied to the AC transfer port is converted into a DC voltage of the energy store or

rectified. In one (optional) (change

power) regenerative mode, the control unit controls the inverter to generate from the voltage that is applied to the energy storage of the vehicle electrical system, a (AC) regenerative voltage to the AC transmission port. In a DC charging mode, the control unit controls the inverter to generate a charging voltage to the energy storage from the voltage applied to the DC power transmission terminal. In this case, the voltage applied to the DC power transmission terminal DC voltage is adjusted to a voltage level of the energy storage. In an (optional) DC regenerative mode, the control unit controls the inverter, from the voltage applied to the energy storage of the vehicle electrical system, a direct current feedback voltage to the DC transmission To conclude. It should be noted again that the term "inverter" is for the sake of clarity, based on only one function performed during the inverter mode. As mentioned, the inverter has different ones

Functions or modes that did not flow into the concept formation. The inverter is therefore not limited to a circuit that is set up exclusively for switching the voltage of the energy store.

The charging voltage at the energy storage can be from a Batte riemanagementsystem the energy storage or a

Recuperation control can be specified as a setpoint. Instead of a charging voltage, a charging current or a charging power can be specified as a setpoint. The phase voltages can be specified by a (higher-level) motor control of the electrical machine, either directly as a voltage setpoint or as a power or torque requirement. Instead of phase voltages, phase currents can also serve as control. The return voltage can be detected by a receiving device of the vehicle electrical system as a setpoint. The receiving device may be configured to receive setpoints from a stationary controller. Instead of a regenerative voltage, a regenerative current or a regenerative power can also be specified.

The control unit may be configured to control at least one of the aforementioned disconnectors, switches and / or selector switches. The control unit can be set up in particular to keep the disconnecting switch in the charging or in the regenerative mode in the open state. The control unit can also be set up to keep the circuit breaker in the inverter or in the recuperation mode in the closed state.

The control unit may further be directed, in the event of a malfunction, to open switches in all bridges of the inverter, such as when a charging fault or a regenerative fault occurs and charging or regeneration is to be interrupted. A pawl may be provided to lock the electric machine (ie to prevent rotation). The control unit may be configured to control the pawl. The control unit may in particular be directed, the pawl in the charging mode and possibly in the back feed mode and lock and the pawl in Wesch selrichtermodus and possibly in the Rekuperationsmodus not to retire ar.

If a DC transmission connection is provided, it is possible that its positive rail is connected directly or via a switch with several or preferably all phase current connections. In other words, the DC power transmission connection is connected directly or via a switch to the phase current connections, preferably to all. As a result, several or all H-bridges can be used in the charging mode or in the regenerative mode. The DC transmission port has a negative rail connected to the negative input power terminal of the inverter. If a switch is used, this is preferably multi-phase before. The switch has a switch element or a phase for each connection between a phase connection and the positive rail (in the case of a multiphase switch). The control unit is set up to keep the switch in an open state in inverter mode or, if necessary, in recuperation mode. The control unit is further configured to hold the switch in a closed state in the charging mode or possibly in the regenerative mode.

Instead, as described above, to connect the positive rail with the phase terminals of the inverter, the positive rail can also be connected via the electric machine or via their phase windings to the phase terminals of the inverter. In other words, the positive rail may be indirectly connected to the phase current terminals via the electric machine. Here, the phase windings are connected in series between the positive rail and the inverter. The negative rail of the

DC transmission connection can be with the negative Be connected to the input power connector of the inverter. As mentioned above (with reference to the DC transmission connection), the term "positive rail" can preferably be replaced by "positive contact" in all variants described here, and the term "negative rail" can be replaced by "negative contact".

The vehicle electrical system is in particular the electrical system of a plug-in hybrid motor vehicle or an electric motor vehicle.

Figures 1-3 are used to further explain the here be prescribed electrical system and show exemplary vehicle electrical system.

Figures 1, 2 and 3 each show a vehicle electrical system with an energy storage ES and an electric machine EM, which are connected to each other via an inverter WR. An AC transmission terminal AC (in Fig. 1, connected to an "AC charger", ie an AC charging station, external to the vehicle electrical system) is connected to the inverter WR The AC charger is an external power source for alternating current and may be single-phase. The

AC-Charger is not part of the vehicle electrical system. The alternating current transmission terminal comprising the phase AC and the neutral conductor N is arranged with the external energy source, i. to be connected to the AC charging station. In bidirectional training of the vehicle electrical system or the inverter, the energy source serves as a sink.

In FIGS. 1, 2 and 3, the energy store ES is connected to the latter via a positive input current connection EA1 and a negative input current connection EA2 of the inverter WR. Parallel to the input current terminals EA1, EA2 a DC link capacitor CI is connected. The inverter WR comprises three H-bridges HB1 - HB3. The H-bridge HB1 has a positive input PE1 and a negative input NE1. The H-bridge HB2 has a positive input PE2 and a negative input NE2. The H-bridge HB3 has a positive input PE3 and a negative input NE3. The positive ones Inputs PE1-3 are interconnected and further connected to the positive input terminal EA1 of the inverter WR ver. The negative inputs NE1-3 are interconnected and further connected to the negative input terminal EA2 of the inverter WR. Each H-bridge HB1-3 has two arms, each having two series-connected semiconductor switches HS. A first of the arms of each H-bridge (shown on the left) connects respectively the negative input and the positive input of the respective H-bridge HB1-3. Each H-bridge has a negative output NA1-3 and a positive output NA3. In each H-bridge, a second of the arms connects the outputs PA1, NA1; PA2, NA2 or PA3, NA3. Each arm has two semiconductor switches HS, which are connected in series via a connection point. For each H-bridge HB1-3 applies that the connection points of the two arms are connected by means of a bridge branch BZ1-3. The bridge branch BZ1-3, which connects the connection points of the two arms in each H-bridge HB1-3, has a series-connected inductance Ll-3. In other words, the inductance Ll-3 in each of the H-bridges HB1-3 connects the connection points of the semiconductor switches HS of the two arms. Each phase connection is connected via a capacitor C21-23 to the negative input current connection EA2 or to the negative inputs NE1-3 of the H-bridges HB1-3. The positive outputs PA1-PA3 of the H-bridges HB1-HB3 correspond to phase current connections of the inverter WR. For this reason, the positive outputs PA1-PA3 of the H-bridges HB1-3 and the phase current terminals PS1-3 of the inverter WR are considered to be equivalent to each other.

The inverter has a first side S1 and a second side S2. The first side S1 is connected to the energy store ES or comprises the input current connections EA1 and EA2. The second side S2 has the phase connections PS1-PS3, which is set up for connection to the electric machine EM. The second side has a branch of an H-bridge HB1-3 in all phases of the inverter, while the first side also has a branch in all phases of the inverter Connection points of the branches via an inductance L1-L3 are interconnected.

With dashed rectangle, the inverter WR is outlined, with the right-hand line of the rectangle, the interface between vehicle electrical system and stationary facilities (DC charger "DC charger" and single-phase change

This charger can be considered as a source of current at this interface is the AC transmission connection and possibly the DC transmission connection.On the left of the line is the vehicle electrical system described here darge presents.

Having mentioned similarities of FIGS. 1-3, further general differences of FIGS. 1-3 will be discussed:

In the circuit of Figure 1, the single-phase AC power transfer terminal comprising the phase terminal AC and the neutral terminal N is connected to a phase terminals PS1-3 and to the potential of the negative input terminal (directly). The single-phase alternating voltage applied to the AC connection (comprising the connections AC and N) is fed to the second side S2 of the inverter WR, in particular via one of the phase connections PA1-3 or via several of these phase connections, which are then used in bundled fashion. The connection between the phase connection PA1 of the inverter and the phase connection AC of the AC transmission connection is shown. The illustrated Pha senanschlüsse PA1-3 are three phases of a three-phase system, but this when connecting the change

Current transmission connection can be used only single phase. The illustrated AC connection comprises (in addition to the zero conductor N) only one phase AC and is thus formed single-phase. Shown by a solid line is a connection of the phase AC of the AC transmission connection with the first phase connection PSI. The connections shown in dashed lines between the second and the third phase connection PS2, PS3 on the one hand and the AC transmission port (or its phase AC) on the other hand, is only shown in dashed lines, since these alternatives are for connection to the Pha senanschluss PSI. In addition, two or all three Pha senanschlüsse PS1-PS3 with the phase AC of the change

be connected current transmission terminal, whereby thereby the connected phase terminals are bundled. In this case, a controller is provided which controls the H-bridges of the inverter for this case synchronized with each other (resulting in the bundling).

An optional DC transmission connection (connection to the inverter in dashed lines) with a positive rail DC + and a negative rail DC- can be connected to two phase connections. It is shown that the positive rail DC + is connected to the phase terminal PA1 and the negative rail DC- to the phase terminal PA2. The optional DC transmission port is connected to the second side of the inverter WR. Either energy is transmitted via the DC transmission terminal DC +, DC- or via the AC transmission terminal comprising the single phase AC and neutral N, or power is transmitted via both DC transmission terminals, with different H-bridges connected to different transmission terminals ,

In the circuit of Figure 2 is AC over the

AC transmission terminal comprising the phase AC and the neutral conductor as described above, transmitted to the second side S2 of the inverter. However, the single phase AC of the AC transmission terminal is not directly connected to one of the phase terminals PA1-PA3 (as in Fig. 1), but is connected to connection points of semiconductor switches HS of arms of one of the H-bridges HB1-3. This concerns the arms of H-bridges HB1-3, which are present on the second side of the inverter, in particular the arms, which are directly connected to the phase terminals PA1-3. With a solid line is a connection between the phase AC of the AC transmission port and the connection point of the right arm of H-bridge HB1 (ie, with the connection point of the second side of the inverter). Alternative compounds as well as combinable compounds are shown in dashed lines.

In FIG. 3, the phase AC of the single-phase AC power transmission connection is connected to the phase connections PS1-3 via the electric machine EM. The alternating current applied to the alternating voltage (= voltage between phase AC and neutral N) is through the electric machine EM, whose windings in series between the change

Current transfer terminal AC and the inverter WR are connected to the second side S2 of the inverter WR fed, in particular via the phase terminals PS1-3. A switch T "selectively connects the windings either in a star configuration or creates an open configuration of the windings where only one or only a subset of the windings are connected to the single phase AC transmission terminal (or its phase AC). In the open configuration, the windings are not interconnected, but the phases of the electric machine EM are electrically isolated from each other and as separate elements in each phase in series between the phase connection AC of the single-phase AC transmission terminal and one of the phase connections PS1-3 of the inverter WR connected.

In FIG. 1, the AC transmission terminal (single-phase phase AC and neutral N) is connected to one of the three phase terminals PS1-3 of the inverter WR.

Shown by solid line is a single phase of the connection, with dashed alternatives (or combinations for bundling) shown. A circuit breaker T is shown, which is polyphase and the individual Pha senwindlungen the electric machine EM (or the electric machine EM itself) separates from the phase current terminals PS1-3 of the inverter WR. The circuit breaker T thus controllably disconnects the electric machine EM from the inverter WR. Alternatively, a circuit breaker T 'may be used within the electric machine EM, which may be the phase windings of the electrical machine EM (approximately in star configuration) separates. The circuit breaker T 'thus triggers the star configuration of the electric machine EM, if this is in the open state. When power is transmitted through one of the transfer ports (AC / N or DC + / DC-), then the disconnect switch T or T 'is in the open state.

The AC transmission terminal comprising the phase AC and the neutral conductor N is part of the vehicle electrical system. The phase AC of the AC transmission terminal is connected to one of the phase terminals PS1-3 of the inverter WR; the neutral conductor of the AC transmission terminal is connected to a DC potential (input DC terminal) of the inverter WR. When power is supplied from the AC transmission terminal including AC and N to the vehicle electrical system, the inverter operates as a converter for converting the AC power into DC voltage for charging the energy storage ES. In this mode and in this transmission direction, the inverter assumes the function of a rectifier and possibly the function of a power or current control or also a voltage regulation.

An optional DC transmission port, which may also be used in the circuits of Figures 2 and 3, has a positive rail DC + (corresponding to a positive contact) connected to the phase terminal PSI (corresponding to a positive output PA1) of a first H- Bridge HB1 is connected. Further, the negative rail DC + (corresponding to a negative contact) of the DC transmission terminal is connected to the phase terminal PS2 (corresponding to another positive output PA2) of another H-bridge HB2.

In FIG. 2, the phase AC of the single-phase alternating current transmission connection is connected to a connection point between semiconductor switches HS of the H-bridges HB1-3. The alternatives or possible combinations are shown in dashed lines and show the connection of the phase AC with a connection point of the H-bridges HB2 and / or HB3. The phase AC of the AC transmission terminal is directly connected to one of the bridge branches BZ1-3 of the H-bridges HB1-3, in particular with a portion of the bridge branches BZ1-3 lying in the second side S2 of the inverter WR. In other words, the AC phase of the AC transmission terminal with one (or - shown in dashed lines - more) center taps of the H-bridges HB1-3 connected, in particular with the center taps, which are in the second side S2 or only via a semi-conductor switch HS are connected to the phase terminals. The second side S2 is connected to the electric machine EM and the phase AC of the AC transmission terminal, and the first side S1 of the inverter WR is connected to the energy storage ES.

In FIG. 3, the phase AC of the single-phase AC power transfer terminal of the inverter WR is connected via at least one of the windings of the electric machine EM to at least one of the phase current terminals PS1-3. A switch T '' connects in a first switch position, the windings with each other in star configuration and in a second switch position the AC phase of the AC - transmission port via at least one of the series-connected windings with the phase terminals PS1-3. The switch T '' is three-phase and has two individual switching elements. These connect in the first switch position two of the three phase windings with the neutral point. If only the connection shown with a solid line is to be realized, then the switch T '' does not require any switchover elements for these phases but only disconnecting elements.

An alternative connection shown in dashed lines provides that the middle phase winding of the electric machine is connected directly and not via a switching element to the phase AC of the AC transmission connection AC. The switch T '' does not affect all phases of the electric machine EM or the terminal AC. However, this is an alternative to the connection shown by a solid line Ver. The switches shown can be used to connect other windings are used, in particular for switching to the second winding, which is directly connected to the phase AC (shown as an alternative dashed lines). Depending on the power to be transmitted, additional windings can be connected (with changeover switch T '') or not.

If the switch shown in dashed lines in the first switching state, the windings of the electric machine EM (or a respective end thereof) are interconnected and there is a star configuration for the phase windings of the machine. When the changeover switch is in the second switching state as shown in solid line, all the windings are connected in series between the phase terminals PS1-3 of the inverter and the phase AC of the AC transmission terminal.

Figures 2 and 3 are shown without DC transmission connection. However, the vehicle electrical system shown there may have a DC transmission terminal which is connected to one or more (or even all) phase current connections PS1-3 of the inverter WR.

For a better overview, only FIG. 1 shows a control unit CTRL of the inverter, which, however, can also be part of the vehicle electrical system of FIGS. 2 and 3. The control unit CTRL controls the semiconductor switches HB and the bridges HB1-3, as indicated by the double arrows. A higher-level control can be formed, depending on the mode, by a controller UE of the battery in the form of a battery management system, or by a controller UE 'which is stationary. The higher-level controller UE or UE 'controls (as indicated by the dashed arrows) to the control unit CTRL, in particular by transmitting a desired value. The vehicle electrical system can have a receiving unit for transmitting signals from stationary components to the control unit CTRL of the vehicle electrical system. The circuits of FIGS. 2 and 3 may also have at least one such controller CTRL, UE or UE '. Furthermore, the control unit CTRL can be activated with the disconnectors T, T 'or the Switch T 'be connected and for different modes of the inverter different switching state to control this.

In the figures 1-3 capacitors C21-C23 are shown, each of which connect a phase connection PS1-3 (corresponding to a positive output PA1-3 of the inverter WR) to a negative input current connection EA2 of the inverter WR. All positive input terminals PE1-3 of H-bridges HB1-3 are connected to positive output terminals PA1-3 of H-bridges HB1-3. These are in turn connected to positive input current connection EA1 of the inverter WR. All negative input terminals NE1-3 of H-bridges HB1-3 are connected to the negative input terminals NA1-3 of H-bridges HB1-3. These are in turn connected to negative output terminal EA2. Between the positive input current connection EA1 and the negative input current connection EA2 (or between all positive and all negative input connections of the H-bridges HB1-3), a capacitor CI is connected. The negative output terminal EA2 is directly connected to the negative input terminal EA1; both can have the same potential, in particular a ground potential.

Claims

claims 1. vehicle electrical system with an inverter (WR), a  electrical energy storage (ES), an electric machine (EM) and a single-phase change  Power transmission connection (AC), which is set up energy between one with the change  power transmission terminal (AC) connectable external AC external power source (AC charger) on the one hand and the vehicle electrical system on the other hand, wherein the inverter (WR) has a first side (S1) and a second side (S2) and is arranged to transmit power between these sides,  - The first side (Sl) of the inverter (WR) via a positive and a negative input power connection (EA1, EA2) of the inverter (WR) to the energy storage (ES) is connected;  - The second side (S2) of the inverter (WR) via at least two phase current connections (PSI, PS2, PS3) of the inverter (WR) to the electric machine (EM) is connected and  - The inverter (WR) has at least two H-bridges (HB1, HB2, HB3), wherein each of the H-bridges (HB1, HB2, HB3) bridges the two sides (Sl, S2) of the inverter (WR), wherein the AC transmission terminal (AC) on the second side (S2) of the inverter (WR) is connected. 2. Vehicle electrical system according to claim 1, wherein the single-phase AC transmission terminal (AC) is directly connected to one or more of the phase current terminals (PSI, PS2, PS3) or indirectly via the electric machine (EM) with one or more of the phase current terminals (PSI, PS2, PS3) is connected. 3. Vehicle electrical system according to claim 1 or 2, wherein the single-phase AC transmission terminal (AC) directly to one or more of the phase current terminals (PSI, PS2, PS3) is connected and the phase current terminals (PSI, PS2, PS3) are connected via a circuit breaker (T) to the electrical machine. 4. vehicle electrical system according to claim 1 or 2, wherein the single-phase AC transmission terminal (AC) indirectly via the electric machine (EM) to the phase current terminals (PSI, PS2, PS3) is connected, in particular via a winding of the electric machine (EM) or over several windings of the electric machine (EM), which are bundled by means of a switch. 5. vehicle electrical system according to claim 4, wherein the single-phase AC transmission terminal (AC), in particular its phase, via a switch (T '') with the  electrical machine is connected, the windings of the electric machine (EM) in a first state un teinander connects and connects in a second state with the AC transmission terminal (AC), and in particular with its phase. 6. Vehicle electrical system according to claim 1, wherein the H-bridges (HB1, HB2, HB3) of the inverter (WR) on the first and the second side of the inverter each have an arm, the positive input power terminal (EA1) to the negative input power terminal (EA2) connects by means of two serial semiconductor switches (HS), which are connected via a connection point, and the change  Current transfer terminal (AC) is connected to the connection points of the arms, which lie on the second side. 7. vehicle electrical system according to one of the preceding claims, wherein the H-bridges (HB1, HB2, HB3) of the inverter (WR) each have two arms, the positive input terminal (EA1) with the negative input current terminal (EA2) by means of two serial Semiconductor switch (HS) connect and wherein the semiconductor switches (HS) of each arm are connected to each other at connection points, further wherein the two connection points of each H-bridge by means of an inductance (LI - L3) are interconnected. A vehicle electrical system according to any one of the preceding claims, further comprising a DC transfer port (DC +, DC-) having a positive and a negative rail, the positive rail having one of the phase terminals (PSI, PS2, PS3) and the negative rail is connected to another of the phase terminals (PS2, PS3, PSI) or to the negative input terminal (EA2).