DE10230384A1 - Circuit arrangement and method for operating this circuit arrangement - Google Patents

Abstract

Circuit arrangement with a drive (BKM) and a generator (G) which is mechanically connected to the drive (BKM), and a supply-board network (VBN), the depending on the operating state of a switching unit (SE1), an additional electrical component (4) in series can be connected. The voltage across the generator (G) is then equal to the sum of the voltage dropping across the electrical component (4) and the supply system voltage. By switching on the electrical component, the power of the generator (G) is increased without increasing the current flowing through the generator (G). In addition to the supply from an energy storage system on the supply system side, the consumers on the supply system side are thus also supplied with energy by the generator (G) during the recuperation operation via the electrical component.

Description

The invention relates to a circuit arrangement with a drive and a mechanically connected to the drive Generator and a method for operating the circuit arrangement.

A pre-published in the not Patent application (PCT / DE01 / 00601) disclosed circuit arrangement has an internal combustion engine and a mechanically connected thereto integrated starter generator (ISG). The integrated starter generator invites the generator operation a double layer capacitor and / or an accumulator to a first voltage. In motor operation becomes the integrated starter generator with that in the double layer capacitor or driven energy stored in the accumulator.

This circuit arrangement is characterized is characterized in that the positive DC voltage terminal of a bidirectional AC / DC converter depending on operating status via two Switch in one case with the positive pole of the accumulator and in the other Case connected to the positive terminal of the double layer capacitor is. The tension over one between the positive and the negative DC voltage connection the AC / DC converter arranged intermediate circuit capacitor via a current flow in the AC / DC converter or from the AC / DC converter out to be adapted to the voltage of the energy store to be connected. This allows balancing currents during the conductive switching of the switch to a minimum value.

In such a circuit arrangement, the heat released during braking of the vehicle kinetic energy into converted electrical energy and temporarily stored in an energy store become. The recovery the kinetic energy released when braking is called recuperation designated. The aim is to be much higher, the recuperation, than the average regenerative power.

The kinetic energy released when braking should not be deprived of the energy balance of the vehicle and in Thermal energy be converted, but are largely be converted into electrical energy and suitable electrical, capacitive storage devices supplied become. Further, a motor operation with voltages to here well above the Board supply voltage possible his.

An embodiment of such a circuit arrangement with a mechanically coupled to the internal combustion engine integrated starter generator, which follows a bi-directional AC / DC converter which is in 4 shown. To the two outputs of the direct voltage side of the AC / DC converter, an intermediate circuit capacitor is electrically connected. The negative terminal of the DC link capacitor and connected to it, negative DC voltage connection of the AC / DC converter connected to the reference potential of the circuit.

The positive connection of the intermediate circuit capacitor and the positive DC connection of the perform AC / DC converter to two parallel switches.

The first switch connects the positive connection of the AC / DC converter with the positive pole of one 36-volt battery, with the large loads lying parallel to it, the other connections of which are connected to the reference potential, and with a third switch.

The second switch connects the positive connection of the AC / DC converter with the positive connection a double layer capacitor, the negative connection with is connected to the reference potential, and to a fourth switch.

The other two ports of third and fourth switches are with each other and with a positive Connection of a DC / DC converter connected. The positive terminal the other transducer side with an accumulator and this Accumulator parallel small loads are electrically connected.

The first is in recuperation mode Switch not conductive and the second switch switched on. The double layer capacitor is generated by the generator at the electrical energy charged. The first battery can in this Switching state absorb any energy. The supply of large loads is carried out in this operating state regardless of the power demand solely from the first accumulator. The small loads are over the second accumulator and, if the third switch is closed, additionally off the first accumulator supplied.

The operations performed by this circuit are controlled by an unillustrated control / regulating circuit / regulated. Also, the determination of the working direction of the converter (up or be Down conversion) the charging of the intermediate circuit capacitor to a certain one Voltage value and the switch positions of the four switches of one Not shown control / regulating circuit controlled / regulated.

A disadvantage of this circuit arrangement, is it that the wiring system and the associated large and small loads in recuperation even in a large power requirement exclusively are supplied from the accumulators.

If no torque support (boost operation) of the internal combustion engine is provided during the acceleration phases of the vehicle and no consumers can be connected in parallel to the double-layer capacitor, the energy stored in the double-layer capacitor cannot be released. This leaves the Double layer capacitor is charged and can not absorb any more energy in the next Rekuperationsvorgang.

From the published application DE 43 07 907 A1 a method for controlling a generator in a motor vehicle is known. This procedure describes how the voltage is adjusted on the generator in dependence on the respective operating state. So that the generator can deliver to charge a battery by the recuperation of brake energy more power, the generator voltage is increased by the recuperation. In order to increase the power consumption further by the generator, a consumer can be switched on additionally. This consumer can in turn charge an energy storage device with the converted into electrical energy kinetic energy by an additional energy conversion again.

The additional load is here only switched to the power consumption at the recuperation to increase. However, the power consumption is limited by the generator voltage only up to the for the consumers of the motor vehicle maximum permitted value (e.g., from 14 V to 16 V) increases can be. If the said additional consumers previously is switched on due to a need is a recuperation not possible. The recuperation is in this case, despite a high Power demand lost.

Although the known method increases the state of charge of the battery and thus also the starting power However, given the recuperation energy is only partially for one electromotive support of the internal combustion engine.

A two power supply device for a motor vehicle from the utility model DE 201 13 916 U1 known. The derivable from the generator electrical generator voltage is in this case supplied via a first terminal for deriving a first voltage to a variable resistor. The variable resistor is a second terminal for deriving a second voltage, and that the on-board network voltage, and connected downstream of a generator controller. In addition, the generator voltage can be a high-power energy storage are preferably fed via a diode. This high power energy storage device can be preferably carried out as a capacitor, especially as a supercap capacitor.

The stored in the high electrical energy storage electrical energy can be a comfort and / or high-current converter to disposal be put.

The variable ohmic resistance is here only for converting electrical energy into thermal energy.

The case of a Rekuperationsvorgang by increasing the Ohmic resistance recovered Kinetic energy can only be converted into thermal energy become, i.e. if no thermal energy can be dissipated, the ohmic Resistance will not be arbitrarily increased.

If, in such a known Dual voltage supply device instead of ohmic resistance a consumer uses, which requires a minimum voltage, the power energy storage must also have a minimum voltage. The one available for storing the recuperation energy Energy content of the energy storage capacity thus considerably reduced.

The object of the invention is a circuit arrangement and a method for operating the circuit arrangement to create safe supply the electrical consumers with energy can.

This object is achieved by a circuit arrangement with the features of claims 1 or 2 and by a A method of operating the circuit arrangement having the features of claim 10 dissolved.

The circuitry can be divided into two sub-networks: a first subnet Rekuperationsnetz and a second sub-network, the supply network board (with, for example 12V, 24V and / or 42V).

A first transducer (e.g., an AC voltage converter) with a first input / output side and a second input / output side is electrically connected to the generator with the first input / output side.

The supply board network can vary depending on Operating state over a first switching unit from the first converter and thus also from the generator are electrically disconnected and a first electrical component also via the first switching unit again electrically with the first converter and thus again with the Generator to be connected. The voltage across the generator is then equal to the sum of the over the first electrical component dropping voltage and the voltage the on-board electrical system (vehicle electrical system voltage). By switching the first electrical component is so without increasing the flowing through the generator Current, the generator output increases.

The recuperation network is on this Wise variable in tension, its tension is dependent on the tension of the generator dependent and can significantly higher Values than for the vehicle electrical system voltage permitted accept.

In contrast, the supply board power voltage stable, i.e. the need of the on-board electrical system and thus the battery current is generated by connecting the first electrical component controlled (voltage divider).

In addition to the supply by a suitable energy storage (e.g. accumulator or fuel cell) the on-board electrical system consumers are thus also during the recuperation over the first electrical component and the first switching unit from the generator energized.

Consumers of supply on-board network so - even in which an increased in situations Voltage required - with its tension of the electrical energy generated at the generator.

In a second embodiment of Circuit arrangement, the circuit arrangement has a second switching unit on, which is connected on the one hand to the electrical component. To the others can said second switching unit, the electrical component alternatively the supply system or with the second input / output side of the first converter are connected.

For small generator voltages can so, by connecting that connected to the second switching unit Output of the electrical component to the second input / output side the first converter, the voltage across the electrical component can be increased. On the other hand, the voltage can also be reduced by connecting the electrical Component are lowered with the supply system. simultaneously can thereby the current flowing into the on-board electrical system be controlled coarsely.

Advantageous embodiments of the Invention are in the subclaims described.

The generator during the Recuperation only voltage limits (e.g. minimum 17V, maximum 58V) and a maximum current or a maximum power (e.g. 150A, 8kW). The voltage of the generator is within these limits inter alia determined by the control of the powertrain.

The recuperation network can also have a Energy storage compared to Mass are stabilized and / or supply consumers who are insensitive across from the voltage fluctuations occurring in the recuperation network.

Instead of a generator can also an integrated, or non-rotatably connected to the drive train find a belt driven starter generator application.

This has the advantage that the in a power energy store and the energy store of the power supply on-board network stored energy is returned to the starter generator and so the internal combustion engine through the starter generator acting as an electric motor supports can be.

The connections on the second input / output side of the first converter is often a capacitor connected in parallel with the controller the converter regulates the voltage on the second input / output side the first converter permits.

This used especially in starter generators So-called intermediate circuit capacitor increases the requirements per se to the switching unit as without the first converter, the voltage differences between the connections the switch would lead to high equalizing currents.

The function of the first converter can be used here, the voltage of the intermediate circuit capacitor be adjusted so that the voltages on both sides of a switch the switch approximately are the same and an almost load-free shifting is possible.

The energy transfer from the generator to the on-board electrical system can about the series-connected electrical component and in addition a second transducer carried out, which is arranged so as to energy can from Rekuperationsnetz in the supply board network and / or vice versa. In addition to the rough voltage regulation by switching on the first one electrical component can fine-tune the voltage across the second transducer carried out.

Further allows the second transducer any necessary increase the generator current over the electricity in the on-board electrical system through energy transmission from the supply system into the recuperation network.

Since not all of the generator transmitted into the supply system Energy over the second transducer transferred , this second converter can therefore be compared to the solution without the serial electric component to be dimensioned smaller which brings cost and weight savings. Will continue the supply board line-side consumer supplying battery protected by the fact that the voltage on this accumulator stabilizes and thus its service life is prolonged.

In the electric component can it is both a capacitive component, such as one Double layer capacitor or a secondary battery (e.g., rechargeable NiMH battery), as well as an ohmic component, such as an electrical one Heating act. Also ohmic-inductive components like electric motors or combinations of different components can be used as electrical component are used.

The electrical component can store kinetic energy converted into electrical energy or convert into mechanical o of thermal energy. It is also storing this energy in a suitable energy store possible.

The generator or a starter generator may be for example a three-phase asynchronous.

The used in the switching units Switches have two stable states. Both in conducting and the non-conductive state, it is advantageous if the Power loss at the switches is as low as possible.

The supply system can be as Voltage but also be designed as a multi-voltage electrical system. With a multi-voltage on-board network, between the sub-networks, which have different voltage levels, for example voltage converters be used.

Several embodiments are as follows explained in more detail with reference to the schematic drawings. Show it:

1 a circuit arrangement according to the invention with a first electrical component,

2 A second embodiment of an inventive circuit arrangement with a first and a second electrical component,

3 a further embodiment of a circuit arrangement according to the invention with a first electrical component, and

4 known circuitry of a dual-voltage vehicle electrical system.

1 shows a circuit arrangement according to the invention with an internal combustion engine BKM as the drive and a generator G mechanically connected to the internal combustion engine BKM. Instead of or in addition to an internal combustion engine, other drives, for example a driven axle, are also possible.

The generator is on the AC voltage side with a first voltage converter 1 connected. this converter 1 is embodied as a bidirectional AC power converter (AC / DC converter). This is connected in parallel on the DC side of an intermediate circuit capacitor C. A voltage U1 drops across the intermediate circuit capacitor C.

about a arranged in two parallel switches S1 and S2 existing first switching unit SE1 can be the positive connection of the intermediate circuit capacitor C on the one hand directly - via electrical Lines - with be connected to a supply system VBN (switch S1 closed) and / or the other indirectly via one first electrical component with the VBN electrical supply system are connected (switch S2 closed).

In the illustrated embodiment, the first electrical component hereafter as an energy storage 4 , For example, considered to be a double layer capacitor and the generator as a starter generator G.

The supply board network VBN has in this embodiment an accumulator B2 and consumer v on. The accumulator B2 v consumers connected in parallel. To consumers v falls a second voltage U2, namely the vehicle electrical system voltage.

A second transducer 3 Which is designed as a bidirectional DC-DC converter (DC / DC converter), is arranged between the Rekuperationsnetz and the supply board network VBN. The connection side of the second converter on the recuperation network side 3 is on the one hand to the positive terminal of the energy accumulator 4 and on the other to ground electrically connected. The board supply primary power supply side is on the one hand to the positive terminal of the power supply on-board network VBN and on the other also electrically connected to ground.

The operations performed by this circuit operations, in particular the determination of the working direction of the transducer 1 and 2 (Up or down conversion), the charging of the intermediate circuit capacitor C to a certain voltage value and the switching positions of the switching unit SE1 are controlled by a control circuit, not shown. For this purpose, the switches S1 and S2 of the switching unit SE1 and he switch S5 connected to the control circuit.

About the second transducer 3 energy can be transferred between the two networks, and thus the supply-board network voltage to be fixed or a discharged energy storage 4 can be recharged from the energy store B2.

Depending on the operating conditions, the Generator power controlled. For example, the generator power, if it exceeds a predetermined threshold, initially to zero be reduced. In this way, the closed switch can S1 virtually power-free and open the direct electrical connection to the VBN supply system is disconnected become. This process occurs for example in a Rekuperationsvorgang on.

Subsequently, the intermediate circuit capacitor C through the AC / DC converter 1 on across the energy storage 4 falling voltage charging. Switch S2 is now also closed almost without power. The supply board network VBN is now on the Energeespeicher 4 and the switching unit SE to the generator G connected.

An additional switch S5 allows an adaptation of the voltage of the intermediate circuit capacitor C to the voltage supply of the vehicle electrical system VBN using the DC / DC converter 3 , For this purpose, when the closed converters 1 and 3 First, the switch S5 opened. Then, the DC / DC converter 3 charging the intermediate circuit capacitor C or discharged. Switch S2 can now be opened almost without power.

If necessary, energy can be supplied via the DC / DC converter 3 be transferred to the supply board network VBN.

Decreases the generator power under another predetermined threshold, so after charging of the intermediate circuit capacitor, the switch S2 is opened again and closing switch S1 again.

The thresholds are in practice by the requirements of the drive train, but also by other parameters, such as the state of charge of the power energy storage or the performance of the DC / DC converter 3 Predetermined.

Is it the energy storage 4 - as is assumed here - to a line energy storage, such as a double-layer capacitor, so it should have the lowest possible state of charge at the beginning of Rekuperationsvorgangs. After a maximum expected recuperation time, the energy store should 4 but then be fully charged.

• – Motor aus: Es ist keine Generatorleistung möglich, lediglich der Energiespeicher versorgt das Versorgungsbordnetz VBN. Im in 1 dargestellten Ausführungsbeispiel ist in dieser Fahrsituation der Schalter S1 offen und der Schalter S2 geschlossen. Der DC/DC-Wandler 3 wird als abgeschaltet betrachtet. Der Zwischenkreiskondensator kann wegen der fehlenden Motordrehung in seiner Spannung nicht angepasst werden. Der Zwischenkreiskondensator muss also die Span nung des Speichers aufweisen, der den Generator für den Startvorgang mit Energie versorgt. Diese Fahrsituation tritt auch ein, wenn der Motor beispielsweise an einer Ampel kurzzeitig abgeschaltet wird (Start-Stop-Betrieb).
• – Start (Entladung der Speicher in den Startergenerator): Der Schalter S2 ist geschlossen und der Schalter S1 offen. Der DC/DC-Wandler 3 soll in der folgenden Betrachtung seine maximale Leistung in das Versorgungsbordnetz VBN abgeben, um den Akkumulator zu schonen. Hierdurch wird Leistung aus dem Rekuperationsnetz in das Versorgungsbordnetz VBN übertragen. Die Versorgungsbordnetzspannung U2 wird an die Bedürfnisse des Akkumulators (Temperaturkompensation) über die Leistung des DC/DC-Wandlers 3 angepasst. Die maximale Startdauer wird durch die Entladedauer des Energiespeichers 4 bestimmt.
• – Leerlaufladung (Ladung des Energiespeichers 4 hat Priorität): Der Schalter S2 ist geschlossen und der Schalter S1 offen. Der DC/DC-Wandler 3 wird als abgeschaltet betrachtet. Der Generator G liefert genau den vom Versorgungsbordnetz VBN benötigten Strom, der zusätzlich auch den Energiespeicher 4 lädt. Die Generatorleistung wird durch die Spannung des Akkumulators bestimmt (Temperaturkompensation). Bei Erreichen der Maximalspannung des Energiespeicher 4 wird die Leerlaufladung beendet. Eventuell muss für diesen Zustand die Leerlaufdrehzahl des Antriebs angehoben werden, damit auch im Leerlauf genügend Energie zur Verfügung gestellt wird.
• – Anfahren (Unterstützung des Verbrennungsmotors bei sehr kleinen Drehzahlen): Schalter S2 ist geschlossen und Schalter S1 offen. Der DC/DC-Wandler 3 überträgt seine Maximalleistung aus dem Rekuperationsnetz in das Versorgungsbordnetz VBN. Hierdurch wird der Akkumulator entlastet. Der integrierte Startergenerator G arbeitet als Motor. Die Versorgungsbordnetzspannung wird, soweit möglich, an die Bedürfnisse des Akkumulators (Temperaturkompensation) über die Leistung des DC/DC-Wandlers 3 angepasst. Nach Entladung des Energiespeichers 4 wird der Fahrzustand Anfahren und somit auch die Unterstützung des Antriebs beendet.
• – Generatorbetrieb bei entladenem Energiespeicher 4 Dieser Zustand wird nur erreicht, wenn der Energiespeicher 4 komplett entladen ist und dann eine Potenzialdifferenz von 0V zwischen dem ersten und dem zweiten Anschluss aufweist. Nur der Schalter S1 oder die Schalter S1 und S2 sind geschlossen. Der DC/DC-Wandler 3 ist abgeschaltet. Der Generator G liefert genau die vom Versorgungsbordnetz VBN benötigte Leistung und regelt auf die vom Energiespeicher B2 geforderte Spannung (Temperaturkompensation). Es kann sinnvoll sein, diesen Zustand ganz entfallen zu lassen, und den Energiespeicher 4 nie komplett zu entladen.
• – Generatorbetrieb mit geladenem Energiespeicher 4 Schalter S2 ist offen und Schalter S1 ist geschlossen. Aus dem Energiespeicher 4 liefert der DC/DC-Wandler 3 zusammen mit dem Generator den vom Versorgungsbordnetz VBN benötigten Strom. Die Leistung des DC/DC-Wandlers 3 orientiert sich am Wirkungsgrad von Antrieb BKM und Generator G. Wenn der Wirkungsgrad hoch ist, sinkt die übertragene Leistung aus dem Rekuperationsnetz in das Versorgungsbordnetz VBN. Unter Umständen kann sogar Energie aus dem Versorgungsbordnetz VBN in das Rekuperationsnetz übertragen werden. Die Generatorleistung orientiert sich an den Spannungsanforderungen des Akkumulators B2 (Temperaturkompensation). Alternativ kann der Energiespeicher 4 auch über einen weiteren Verbraucher zum Versorgungsbordnetz VBN hin oder zu Masse entladen werden. Nach (kompletter) Entladung des Energiespeichers 4 wird in den Generatorbetrieb bei entladenem Energiespeicher umgeschaltet. Die Entladung des Energiespeicher 4 kann aber auch in einem Teilladezustand beendet werden.
• – Rekuperation (Erhöhte Leistung des Generators) Der Schalter S1 ist offen und der Schalter S2 ist geschlossen. Ausgehend von einem (nahezu) entladenen Energiespeicher 4 arbeitet der DC/DC-Wandler 3 zu Beginn der Rekuperation mit maximaler Leistung und entzieht diese dem Versorgungsbordnetz VBN. Auf diese Weise wird dem Energiespeicher 4 Energie zugeführt. Die Spannung des Akkumulators B2 bestimmt die Generatorleistung (Temperaturkompensation). Mit zunehmendem Ladezustand des Energiespeicher 4 steigt die Spannung am Generator und daher sinkt bei konstanter Leistung der Strom, sowohl in der in das Rekuperationsnetz fließende, als auch der in das Versorgungsbordnetz VBN fließende Strom. Um diesen Effekt zu kompensieren reduziert sich daher die DC/DC-Wandlerleistung durch den Nullpunkt bis zur maximalen Leistung im Abwärtsbetrieb (vom Rekuperationsnetz in das Versorgungsbordnetz VBN), um den Strom in das Versorgungsbordnetz VBN konstant zu halten. Kleine Schwankungen im Bedarf des Versorgungsbordnetzes VBN können ebenfalls durch den DC/DC-Wandler 3 ausgeglichen werden. Bei Erreichen der Maximalspannung des Energiespeichers 4 wir die Rekuperation beendet.
• – Leistungssteigerung (Steigerung der Ausgangsleistung bei Generatoren, deren Leistung durch Spannungserhöhung am Ausgang ansteigt) In bestimmten Drehzahlbereichen des Generators (insbesondere bei hohen Drehzahlen) steigt die Ausgangsleistung durch Anhebung der Ausgangsspannung. Reicht die generatorische Leistung des Generators G nicht zur Versorgung der Verbraucher v aus, so wird die Abgabeleistung dadurch erhöht, dass die mittlere Spannung am Generator G größer ist. Hierzu wird der Ausgang des Wandlers 1 periodisch abwechselnd mit dem Versorgungsbordnetz VBN (niedrige Spannung, S1 geschlossen, S2 offen) und dem Rekuperationsnetz (hohe Spannung, S1 offen, S2 geschlossen) verbunden. Der DC/DC-Wandler 3 überträgt in dieser Betriebsart maximale Leistung aus dem Rekuperationsnetz in das Versorgungsbordnetz VBN.
• – Interne Starthilfe (Ladung des Energiespeichers 4 aus dem Energiespeicher B2 des Versorgungsbordnetzes VBN bevor der Motor gestartet wird): Der Schalter S1 ist offen und der Schalter S2 ist geschlossen. Der DC/DC-Wandler 3 transferiert seine maximale Leistung aus dem Akkumulator B2 auf das Plus-Spannungsniveau des Energiespeicher 4. Der Generator G arbeitet nicht. Bei Erreichen der minimalen Startspannung über dem Energiespeicher 4 wir die interne Starthilfe beendet.

It can at least nine situations are distinguished, which are implemented according to the requirements of the motor vehicle:

• - Engine off: It is possible no generator power, only the energy store supplies the supply board network VBN. In in 1 illustrated embodiment disclosed in this driving situation the switch S1 and the switch S2 is closed. The DC / DC converter 3 is considered to be turned off. The intermediate circuit capacitor can not be adjusted because of the lack of motor rotation in its tension. Thus, the intermediate circuit capacitor has to have the clamping voltage of the memory which supplies the generator with energy for the starting process. This driving situation also occurs when the engine is, for example, switched off for a short time at a traffic light (start-stop operation).
• - Start (discharging of the storage in the Starter Generator): The switch S2 is closed and switch S1 is open. The DC / DC converter 3 is to deliver its maximum power in the supply board network VBN, to conserve the battery in the following analysis. In this way, power is transferred from the Rekuperationsnetz in the supply board network VBN. The supply-board voltage U2 to the needs of the accumulator (temperature compensation) on the performance of the DC / DC converter 3 customized. The maximum start time is determined by the discharge time of the energy storage 4 certainly.
• - Idling charging (charging the energy storage 4 has priority): Switch S2 is closed and switch S1 is open. The DC / DC converter 3 is considered to be turned off. The generator G delivers exactly the current required from the supply board network VBN, which in addition also the energy storage 4 invites. The generator power is determined by the voltage of the battery is determined (temperature compensation). When the maximum voltage of the energy storage is reached 4 the idle charge is terminated. the idle speed may need the drive to be raised for this condition, so that enough energy is made available even at idle.
• - starting (support of the engine at very low speeds): switch S2 is closed and switch S1 is open. The DC / DC converter 3 transmits its maximum output from the Rekuperationsnetz in the supply board network VBN. This relieves the battery. The integrated starter generator G works as a motor. The supply-board voltage, as far as possible to the needs of the accumulator (temperature compensation) on the performance of the DC / DC converter 3 customized. After discharge of the energy store 4 the drive start-up state and thus the drive support is ended.
• - Generator operation with discharged energy storage 4 This state is only reached when the energy storage 4 completely is discharged, and then has a potential difference of 0 V between the first and the second terminal. Only the switch S1 or the switches S1 and S2 are closed. The DC / DC converter 3 is switched off. The generator G provides exactly the power required by the vehicle electrical system supply VBN and adjusted to the required by the energy storage voltage B2 (temperature compensation). It may make sense to let this state be completely omitted, and the energy storage 4 Never unload completely.
• - Generator operation with charged energy storage 4 Switch S2 is open and switch S1 is closed. From the energy storage 4 the DC / DC converter supplies 3 together with the generator, the power required by the VBN supply system. The performance of the DC / DC converter 3 based on the efficiency of the drive and BKM generator G. If the efficiency is high, the transmitted power decreases from the Rekuperationsnetz in the supply board network VBN. Perhaps even energy from the power supply board network VBN can be transferred to the Rekuperationsnetz. The generator power based on the voltage requirements of the battery B2 (temperature compensation). Alternatively, the energy storage device can 4 are discharged via a further load to the pension board network VBN or towards mass. After (complete) discharge of the energy store 4 is switched to generator operation when the energy storage is discharged. The discharge of the energy storage 4 but can also be ended in a partial state of charge.
• - recuperation (increased power of the generator), the switch S1 is open and switch S2 is closed. Starting from an (almost) discharged energy storage 4 the DC / DC converter operates 3 at the beginning of recuperation with maximum performance and deprives them of the power board network VBN. In this way, the energy storage 4 Energy supplied. The voltage of the battery B2 determines the generator power (temperature compensation). With increasing state of charge of the energy storage 4 the voltage at the generator rises and therefore the current decreases with constant power, both in the current flowing into the recuperation network and in the current flowing into the supply system VBN. To compensate for this effect, the DC / DC converter power is therefore reduced through the zero point to the maximum power in downward operation (from the recuperation network to the supply system VBN) in order to keep the current in the supply system VBN constant. Small fluctuations in the demand of the supply board network VBN can also through the DC / DC converter 3 be balanced. Upon reaching the maximum voltage of the energy storage 4 We ended recuperation.
• - Increase in output (increase in output power for generators, the output of which increases due to voltage increase at the output) In certain speed ranges of the generator (especially at high speeds), the output power increases by increasing the output voltage. Reaches the regenerative power of the generator G is not to supply the consumer v, so the output power is increased by that the mean voltage at the generator G is larger. For this, the output of the converter 1 periodically alternately to the supply on-board network VBN (low voltage, S1 is closed, S2 open) and the Rekuperationsnetz (high voltage, S1 is open, S2 is closed) is connected. The DC / DC converter 3 transferring maximum power from the Rekuperationsnetz in the supply board network VBN in this mode.
• - Internal starting aid (charge of the energy store 4 B2 from the energy storage of the vehicle electrical system supply VBN before the engine is started): The switch S1 is open and switch S2 is closed. The DC / DC converter 3 transferred its maximum power from the battery B2 to the plus voltage level of the energy storage 4 , The generator G is not working. Upon reaching the minimum starting voltage across the energy storage 4 we completed the internal jumper.

2 shows another embodiment of a circuit arrangement according to the invention. Functionally identical elements as in the in 1 Circuit arrangement shown have the same reference numerals.

Via a likewise two switches S1 and S2 comprehensive switching unit SE1 is here the positive terminal of the intermediate circuit capacitor C and a terminal of a first electrical component, in this case an energy store 4 electrically connected. The other connection of the energy storage 4 is electrically connected to the positive terminal of the power supply on-board network VBN.

Also on the first switching unit SE1 is the positive terminal of the DC link capacitor C to a first terminal of a second electrical component, in this case a high-power consumers 4 ' and via this with a second switching unit SE2. This second switching unit SE2, the two switches S3 'and S4' which connects the high-power consumers 4 ' either electrically with ground or the VBN supply system.

The positive terminal of the energy storage 4 is also here with a bi-directional DC 3 electrically connected to its opposite positive terminal as in the first embodiment (see Fig. 1 ) Is connected to the positive terminal of the supply on-board network VBN. The two negative connections of the DC-DC converter 3 are connected to ground.

Alternatively, the DC-DC converter can 3 even with the high-power consumers 4 ' be electrically connected.

The generator G supplies a voltage in a range from 30V to 58V. The power output of the generator G depends on the energy needs of high-performance consumer 4 ' and that of the consumer v of the supply system VBN. Diser energy requirement here is 0 to 8000 W. In the recuperation will possible the maximum power can be delivered from 8000W for a few seconds from the generator G.

The high-power consumers 4 ' should be specified according to the 42V standard between 30V and 48V. The power consumption of the high-performance consumer 4 ' (For example, an air conditioning compressor), depending on the power requirement between 800W and 3000W, and can be adjusted continuously.

Via the switch S2 of the switching unit SE1 of high-performance consumer can 4 ' also be switched off completely.

The power demand of the on-board network supply VBN varies in this embodiment, depending on the load profile between 200W and 1200W. The DC-DC converter 3 Here, for example, with a maximum power of 1200W, the supply board network VBN supplied at a voltage level of 12V.

The energy storage 4 absorbs the recuperation power and then returns it to the high-performance consumer 4 ' and to supply consumers v of the on-board electrical system VBN.

The larger the voltage range, in which the energy storage 4 is operating, the greater the proportion of its energy content, are used can.

Consequently, to the energy storage 4 to be able to be dimensioned smaller and / or the generator G, the negative terminal of the high power load 4 ' connected via switch S4 'either to ground or via the switch S3' to the positive terminal of the power supply on-board network VBN.

At a low output voltage U1 of the generator G (due to the voltage across the energy storage 4 ) Or at a low power demand of the on-board network supply of the high-power load is VBN 4 ' operated between generator G and ground (switch S3 'open and switch S4' closed) and at high voltage and high power requirements of the on-board electrical system VBN, the current flows through the high-power consumer 4 ' ( 'Closed and switch S4' switch S3 open) in the onboard supply network VBN.

The power supply board network VBN must in the second case (switch S3 'closed and switch S4' open) can record the v offered by current consumers. Any current differences between high-performance consumer 4 ' and the supply system VBN can from the DC-DC converter 3 be compensated within certain limits. Larger current differences can only by electrically connecting the high-power load 4 ' be solved by mass.

Even with the 2 illustrated circuit are carried out operations, in particular the determination of the working direction of the transducer 1 and 3 (Up or down conversion), the charging of the intermediate circuit capacitor C to a certain voltage value and the switching positions of the four switches S1, S2, S3 'and S4' again controlled / regulated by a control circuit, not shown. For this purpose, the switches S1 and S2 the first switching unit SE1 and the switches S3 'and S4' of the second switching unit to the control circuit are connected.

In 3 A third embodiment of a circuit arrangement according to the invention is shown. Here, the in was 1 Circuitry shown a switch S6 between the negative terminal of the electrical component, such as an energy storage 4 And consumers v of the supply board network VBN added.

Functionally identical elements to those in the 1 and 2 Circuit arrangements shown have the same reference numerals.

A further difference from the in 1 circuit arrangement shown represents the arrangement of the battery B2, which here between the negative terminal of the energy accumulator 4 and mass is arranged.

This modification of the circuit arrangement 1 the voltage at the battery B2 can be increased by opening the switch S6. This may prove to be advantageous in recuperation, especially when the voltage U1 is small and the consumer v have a low power consumption.

In addition, the internal resistances the switches S1 to S6 can be used for current measurement.

Carried out operations of the in the third embodiment Circuit arrangement shown are as in the other embodiments controlled / regulated by a control circuit, not shown.

4 shows a circuit arrangement of a known motor vehicle electrical system.

Functionally identical elements to those in the 1 and 2 Circuit arrangements shown have the same reference numerals.

Control of operations in the 1 - 3 illustrated circuitry is carried on one hand due to user-controlled sizes, such as accelerator pedal position, preselected vehicle speed, selected transmission gear ratio, braking and / or clutch operation and on the other hand, due to operational variables such as speed, torque and / or speed.

Alternatively, the switching elements of the switching units SE1 and SE2 by external, such as caused by the driver, signals to be controlled.

Safety critical components can to one if possible reliable Ensure energy supply directly from the generator Rekuperationsnetz be supplied and / or the supply board network. These components are, for example, via diodes with the positive ones connections of the generator, the first and the second subnetwork.

Claims (10)

Circuit arrangement with a drive (BKM) and a generator (G) which is mechanically connected to the drive (BKM) comprising - a supply-board network (VBN), with at least one electrical energy accumulator (B2) and at least one consumer (v), - a first transducer ( 1 ) with a first input / output side and a second input / output side, in which the first input / output side is electrically connected to the generator (G), - a first electrical component (VBN) connected in series ( 4 ), And - a first switching unit (SE1) via which the second input / output side of the converter ( 1 ) On the one hand directly to the supply on-board network (VBN) and on the other hand indirectly via the first electrical component ( 4 can be electrically connected) to the supply board network (VBN). Circuit arrangement with a drive (BKM) and a generator (G) which is mechanically connected to the drive (BKM) comprising - a supply-board network (VBN), with at least one electrical energy accumulator (B2) and at least one consumer (v), - a first transducer ( 1 ) Having a first input / output side and a second input / output side, wherein the first input / output side is electrically connected to the generator (G), - a first electrical component ( 4 ) on the one hand with the first converter ( 1 is) electrically connected, and - a second switching unit (SE2), of which the first electrical component ( 4 ) Can be electrically connected on the one hand to the supply on-board network (VBN) and secondly to the second input / output side of the first transducer. Circuit arrangement according to claim 1 or 2, characterized in that the first electrical component ( 4 ) and / or the second electrical component ( 4 ' ) have inductive, capacitive and / or ohmic components. Circuit arrangement according to one of the preceding claims, characterized in that the first converter ( 1 ) is a unidirectional or bidirectional AC converter. Circuit arrangement according to one of the preceding claims 1 to 4, which has a second converter ( 3 has), on the one hand electrical with the first component ( 4 ), and on the other hand electrically connected to the supply on-board network (VBN). Circuit arrangement according to claim 5, characterized in that the second converter ( 3 ) is a unidirectional or bidirectional DC converter. Circuit arrangement according to one of claims 5 or 6, characterized in that that between the energy storage (B2) and the consumer (v) of Supply on-board network (VBN) is a switch (S6) is arranged. Circuit arrangements according to one of claims 5, 6 or 7, characterized in that between the second input / output side of the second converter ( 3 ) And the supply board network (VBN) is a switch (S5) is arranged. Circuit arrangement according to one of the preceding claims, characterized in that the generator (G), a starter generator. Method for operating a circuit arrangement according to claims 1 to 9, characterized in that, depending on user-controlled variables or on the basis of operating variables, - the first switching unit (SE1) and / or the second switching unit (SE2) is switched, - the power of the generator (G) is controlled, and - the direction and performance of the converter ( 1 ) Or the converter ( 1 and 3 ) is determined.