DE102020201463A1 - High-voltage vehicle electrical system with first and second energy storage and configuration circuit - Google Patents

Abstract

A high-voltage vehicle electrical system with first and second energy stores (E1, E2) and with a configuration circuit (KS) is described, which is set up to connect the energy stores (E1, E2) either in parallel or in series. The high-voltage vehicle electrical system has at least one multi-part consumer and at least one voltage-variable consumer (SV). The multi-part consumer has a first part (T1, P1; Z1) which is connected to the first energy store (E1) and a second part (T2, P2; Z2) which is connected to the second energy store (E2). In the multi-part consumer, the second part (T2, P2; Z2) is electrically isolated from the first part (T1, P1; Z1). The voltage-variable consumer (SV) is connected to the first and the second energy store (E1, E2) via the configuration circuit (KV).

Description

It is known to equip vehicles with an electric drive that is fed by an accumulator. There is also a charging connection in order to be able to charge this accumulator by means of the charging station. In addition to the electric drive, there are other consumers, some of which have lower operating voltages than the electric drive. High-voltage consumers such as the electric drive and high-voltage components such as the accumulator can also have different voltages, in particular if charging is to be carried out with a high voltage of, for example, 800 volts, and the drive operates at a different voltage, for example 400 volts.

It is an object of the invention to show a possible one with which this function can be implemented with simple and inexpensive components, in particular the supply of high-voltage components with a constant voltage, while the voltage of other high-voltage components is preferably adjustable.

This object is achieved by the high-voltage vehicle electrical system according to claim 1. Further properties, features, embodiments and advantages emerge from the dependent claims and the description as well as from the figure.

A high-voltage vehicle electrical system is described with a first and a second energy store, the vehicle electrical system also having a configuration circuit. By means of this, the energy stores can be connected to one another in parallel or in series (depending on the setting of the configuration circuit). If the energy stores are capacitors, for example intermediate circuit capacitances, then at high input voltages the configuration circuit can connect the intermediate circuit capacitors to one another in series so that only half of the total voltage drops across one of the capacitors. This means that each capacitor can only be designed with half the nominal voltage. If the capacitors are connected in parallel, the capacities are doubled.

If the energy stores are batteries, for example high-voltage accumulators, then the series connection of the high-voltage accumulators can be set for charging with 800 V, while for driving, for example, a parallel connection is provided with which the inverter of the electric drive can be operated. If there are other high-voltage components that are connected to these configurable energy stores, their operating voltage also changes depending on the setting of the configuration circuit. However, this may not be desirable, for example, with a heating circuit or a DC voltage converter, for example for the low-voltage range, or with a high-voltage air conditioning compressor, whereby these components (or consumers) must also be able to work both during the parallel and series connection of the energy storage devices . In particular when the energy storage device is designed as a high-voltage accumulator, the components mentioned should be operated with the same voltage, regardless of whether driving is intended or whether charging is carried out at a high voltage.

The invention enables high-voltage components to be operated in spite of a serial or parallel configuration through the configuration circuit, to operate with one and the same voltage, without the need for an additional voltage converter. This is made possible by the fact that the high-voltage component (hereinafter: consumer) is made up of several parts and the parts of the consumer are each connected to one of the energy stores. Since the energy stores each have a voltage that is the same for different configurations of the configuration circuit, the division of the relevant consumer into several parts and the connection to one of the energy stores allows the consumer to operate with one and the same voltage (namely the voltage of the respective Energy storage), without loading the energy storage on one side and without using an additional converter.

The high-voltage vehicle electrical system described here thus has at least one multi-part consumer, which has a first part and a second part. The first part is connected to the first energy store and the second part is connected to the second energy store. The first part is connected to the first energy store (and not to the second part). The second part is connected to the second energy store (and not to the first part). In this case, the respective parts are preferably connected in parallel to the respective energy storage device. The respective parts are directly connected to the relevant energy storage device.

In addition to this multi-part consumer, there is also a voltage-variable consumer, for example represented by high-voltage batteries that work with a first voltage, for example 400 V, when driving and are connected in series for charging in order to be set up for double the voltage for charging. With the use of a consumer split or divided according to the invention in a multi-part consumer or in a first and a second part, this can be independent of the configuration or the current operating voltage of the voltage-variable consumers are operated. At the same time, the voltage-variable consumer can be set for different voltages. The voltage-variable consumer is connected to the first and the second energy store via the configuration circuit. In particular, the voltage-variable load is connected to two external connections of the configuration circuit, while the energy stores are each connected to a (separate) internal connection of the configuration circuit. The configuration circuit is set up to connect the inner connections in parallel to the outer connections (in the case of a parallel configuration), the configuration circuit also being set up to connect the two inner connections in series in the case of a serial configuration, so that the energy stores are in series between the outer connections Connections are available.

In the multi-part consumer, the first part and the second part are galvanically separated from one another. There is no galvanic connection between the first and the second part that lies within the consumer. This galvanic separation within the consumer in relation to the two parts enables the separate connection to a respective one of the two energy stores.

The configuration circuit can have a serial switch which is located between the two energy stores and is connected in series with them. If the serial switch is closed, then the two energy stores are connected to one another in series. Furthermore, two parallel switches can be provided which (when the serial switch is open) each connects one of the two connections of the two energy stores to the opposite external connection of the configuration circuit, so that the energy stores are connected in parallel and this parallel connection is connected to the two external connections of the configuration circuit. The serial switch can be replaced by one or more diodes.

One or more multi-part consumers can be connected. In the case of two multi-part consumers, the first part of the first consumer and the first part of the second consumer are connected to the first energy store. The second parts of the two multi-part consumers are connected to the second energy store. In the case of several consumers, there are generally several first and several second parts, the first parts being connected to the first energy store (parallel) and the second parts being connected to the second energy store (parallel). The at least one first part is connected to the first energy store directly and not via the configuration circuit. The at least one second part is connected to the second energy store directly and not via the configuration circuit. Therefore, the connection between the respective part and the associated energy store does not depend on the setting of the configuration circuit, so that the voltage resulting for parts is in each case independent of the setting or the switching state of the configuration circuit. The multi-part consumer can be an ohmic consumer such as a (multi-part) heating resistor or an air conditioning compressor with a multi-part electrical drive or with a multi-part inverter, or it can be a voltage converter, in particular a DC voltage converter. The multi-part consumer can be viewed as an electrically operated component or as a converter that converts electrical power into heat output or movement or into electrical power (at a different voltage level).

The energy stores can each be intermediate circuit capacitances or capacitors in general, or can also be accumulators. The voltage-variable consumer can be a voltage-variable electric drive, which is designed, for example, for high-load and partial-load operation with different operating voltages. This drive can comprise an inverter that connects the energy storage device (via the configuration circuit) to the electrical machine. Furthermore, the drive can comprise a DC voltage converter, which connects the energy store (via the configuration circuit) to the electrical machine via the inverter. An alternative is that the energy stores are designed as capacitors and the voltage-variable consumer comprises an accumulator, in particular a high-voltage accumulator. The accumulator can be connected to the energy stores directly or via a DC voltage converter (via the configuration circuit). The accumulator is to be regarded as a consumer because it consumes electrical energy in one state, namely in the state of charge. The accumulator is made up of several parts, the parts of the accumulator being connected to one another in a configurable manner. The accumulator has several (in particular two) parts that can optionally be connected to one another in series or in parallel. This configuration (parallel or serial connection) of the parts of the accumulator preferably corresponds to the configuration of the configuration circuit by means of which the energy stores are connected to one another. A device can provide that the energy store and the parts of the accumulator (as a voltage-variable consumer) have the same configuration (serial or parallel) and can provide a synchronous change of the respective configuration.

The first part of the multi-part consumer can have a control circuit. The second part can also have a (further) control circuit, so that each part has a control circuit. The respective control circuits of the parts of the multi-part consumer are preferably provided for power setting, that is to say for setting the power, of the consumer and in particular of heating resistors of the multi-part consumer. In this case, the multi-part consumer is a multi-part electrical heating circuit. Alternatively or additionally, it can be provided that the first part and the second part of the multi-part consumer each have an inverter which is assigned to an electric air conditioning compressor, this air conditioning compressor forming the multi-part consumer. Furthermore, the first and the second part of the multi-part consumer can be formed by inverters of an electric vehicle drive, in particular with two electric machines.

Furthermore, it can be provided that the at least one multi-part consumer has a first and a second chopper. Furthermore, the multi-part consumer preferably has a first and a second primary winding of a transformer direction. The transformer device can be part of a DC / DC converter. The multi-part consumer can be a (galvanically isolating) multi-part or multi-channel DC voltage converter or form a section (such as a primary side) thereof. The first part of the multi-part consumer (designed as a DC voltage converter) is provided by the first chopper and the first primary winding, which is connected downstream of the first chopper. The second part of the multi-part consumer can be provided by the second chopper and the second primary winding, this being connected downstream of the second chopper. The first part of the multi-part consumer can thus be provided by the combination of a first chopper and a first primary winding and the second part can be provided by a second chopper and a second primary winding, these being part of a DC / DC converter. These are in particular part of a primary side of a galvanically isolating DC voltage converter.

A first possibility is that the primary windings are provided on the same core, or on different cores of different transistors. It can thus be provided that the transformer device has a transformer with a core which is encompassed by both the first and the second primary winding. These two primary windings are assigned to the transformer. Alternatively, the transformer device (of the DC-DC converter) can be in two parts and also have two cores, each of which has one of the primary windings. The transformer device may have a first core around which the first primary winding is wound and may have a second core around which the second primary winding is wound. The two cores are not magnetically connected to each other. Alternatively, the cores are magnetically connected to one another, so that the first and second primary windings are provided on cores which are magnetically connected to one another and thus have a uniform core.

The first energy store is preferably provided as a capacitor which is connected to the first chopper, in particular in parallel. The capacitor forms an intermediate circuit capacitor which is assigned to the first chopper. The second energy store is also provided as a capacitor. This is connected (in parallel) to the second chopper. This capacitor then forms a (further) intermediate circuit capacitor which is assigned to the second chopper. The capacitors preferably have the same capacitance value. The windings can also have the same number of turns. If the first and the second energy store are designed as parts of an accumulator, they preferably have the same nominal voltage and the same capacity. In general, the multi-part consumer can have parts that have the same nominal value, for example the same power, the same resistance; in particular, the parts of the multi-part consumer are designed in the same way.

Embodiments in which the multi-part consumer has a first and a second chopper, which are parts of a DC voltage converter (and thus the multi-part consumer is constructed as a multi-part DC voltage converter), a secondary winding can be provided which is magnetically coupled to the first and the second primary winding. If the two primary windings are magnetically connected to one another via the same core, the secondary winding can also be connected to this core. Alternatively, the secondary winding is in two parts and magnetically coupled to both the first primary winding (via a first core) and to the second primary winding (via a second core). If the primary windings are magnetically separated from one another, two secondary windings are preferably provided, one each being connected to the first and to the second primary winding. The at least one secondary winding is preferably followed by a rectifier circuit. This can be a controlled or an uncontrolled rectifier circuit. The at least one secondary winding and the rectifier circuit form a secondary side of an electrically isolating one DC voltage converter. This DC / DC converter, which is made up of several parts, has a primary side which includes the first and second primary windings as well as the first and second chopper. The galvanically isolating DC voltage converter can thus have a two-part primary side, or it can have a two-part primary side and a two-part secondary side.

The choppers are preferably controlled offset from one another, in particular by a chopper control. If there are two choppers, they can be actuated offset by 180 ° to each other. In particular, the chopper is activated by the control in such a way that the phase offset is evenly distributed between the individual choppers. The chopper control is designed to control the chopper according to an interleaving scheme.

The voltage-variable consumer can be a DC-DC converter, in particular a high-voltage converter. This DC / DC converter has a first side which is connected to the configuration circuit. The DC / DC converter has a second side which is connected to a high-voltage on-board network branch of the high-voltage vehicle on-board network. An accumulator or an electric drive of the vehicle can be located in this high-voltage on-board network branch. The first side of the DC / DC converter is connected to the energy storage device via the configuration circuit. The voltage-variable consumer designed as a DC voltage converter can be designed to be bidirectional. In particular, the voltage-variable consumer is designed as an inverse converter, or as a combination of a step-down converter and a step-up converter with a common working inductance. In other words, the voltage-variable consumer can be constructed as a buck-boost converter.

The at least one multi-part consumer can be designed as a multi-part, galvanically isolating DC voltage converter, which is designed in particular to convert a high-voltage voltage to the energy store, for example voltages of 400, 600 or 800 volts, into a low-voltage voltage, for example into a voltage of 48 volts or from essentially 12 volts. The vehicle electrical system can have a low-voltage electrical system branch that is connected to the energy store via the multi-part consumer, the multi-part consumer being designed as a DC voltage converter, in particular a step-down converter.

The multi-part consumer designed as a voltage converter is preferably set up to discharge the energy storage device according to a predetermined current value or to charge it to a predetermined voltage. This applies in particular to energy stores that are designed as capacitors.

A power factor correction filter, for example a Vienna filter, can be connected upstream of the configuration circuit. This in turn can be preceded by an AC voltage charging interface, for example directly or via a circuit breaker device. This can also have filter elements if necessary. A controller can be provided which detects whether the AC voltage interface is single-phase or multi-phase and can be set up to control the configuration circuit for parallel configuration in the case of single-phase assignment, while in the case of multi-phase assignment the configuration circuit is brought into a parallel configuration or is controlled according to a parallel configuration . This applies in particular to embodiments in which the energy stores are designed as intermediate circuit capacitors. If current is introduced into the vehicle electrical system via the AC voltage interface, then, on the one hand, an accumulator can be charged which, for example, connects to the configuration circuit, whereby the multi-part consumer can be operated at the same time, for example a multi-part heating element.

the 1 shows an example of a high-voltage vehicle electrical system with capacities as energy storage.

In the 1 a high-voltage vehicle electrical system is shown, which has an input circuit IN has, which has an isolating circuit CT with a power factor correction filter LF connected is. The power factor correction filter LF also has the function of rectifying and can therefore be called a rectifier. The input circuit IN has an AC voltage charging interface, the three phases L1 until L3 , a neutral conductor and a protective conductor PE. Furthermore, there are filter capacitances and filter inductances in the input circuit IN provided, in particular to suppress interference signals before transfer to a connected AC network.

The power factor correction filter LF or rectifier LF has an AC voltage side, which is connected to the input circuit IN is connected, and has a DC voltage side connected to energy storage E1 , E2 or with a configuration circuit KS connected is. External connections of the configuration circuit KS are with the DC voltage potentials of the DC voltage side of the rectifier LF connected. A reference potential of the rectifier is connected to an internal connection of the configuration circuit KS connected.

The energy storage devices designed as intermediate circuit capacitors E1 and E2 are with DC voltage potentials of the DC voltage converter LF connected, with the capacitors E1 , E2 are connected to one another via two series-connected diodes. The connection point between the diodes is connected to a reference potential of the rectifier. Two changeover switches are used to set the desired configuration, ie are used to set a parallel or serial configuration of the energy storage device E1 , E2 . The neutral conductor PE is with the reference potential of the DC voltage converter LF connected. The switches shown serve for the optional connection of the energy store with one of the DC voltage potentials of the rectifier LF or with the reference potential (ground) of the rectifier LF . The reference potential is also connected to the connection point via which the two diodes of the configuration circuit KS are connected to each other.

To the configuration circuit KS and the energy storage E1 , E2 a multi-part electrical heating circuit closes as a multi-part consumer HE on. This shows initial resistance R1 and second resistors R2 on as well as first transistors T1 and second transistors T2 . The multi-part electrical heating circuit HE has a first part T1 and a second part T2 on, being the first part T1 the first resistances R1 includes and the second part T2 the second heating resistors R2 . The first part and the second part each have a control circuit which is formed by the transistors shown. These are set up to adjust the power through the respective heating resistors. The control circuits of the various parts of the multi-part consumer are preferably activated according to the same setpoint power value.

In addition to the multi-part electrical heating circuit HE Another multi-part consumer is connected to the energy storage (directly). A galvanically isolating DC voltage converter is provided as a further multi-part consumer, with a first and a second chopper in particular as multi-part consumer Z1 , Z2 and associated first and second primary windings P1 , P2 is shown. According to one aspect of the illustrated embodiment, the and the second chopper Z1 , Z2 and the associated first and second primary winding P1 , P2 the other multi-part consumer (in addition to the heating circuit HE ). Another approach provides that these only form part of the (further) multi-part consumer. The galvanically isolating DC voltage converter has next to the primary windings P1 , P2 and the chopper Z1 , Z2 that form a primary side, a secondary side SF on. This secondary side SF has two secondary windings S1 , S2 on, each of which is followed by a controlled full-bridge rectifier circuit. The two primary windings S1 , S2 Downstream rectifiers (controlled rectifiers) have connections that are connected to one another in parallel and lead to a low-voltage connection. A serial connection of the connections would also be conceivable. The low-voltage connection has a ground potential GND as well as a positive potential, which is designated by 12 volts. A low-voltage on-board network branch can be connected to these connections, for example an on-board network branch with a nominal voltage of approximately 12 volts.

In addition to the multi-part consumers, there is a voltage-variable consumer SV shown. This is with the external connections of the configuration circuit and thus with the external connections of the energy store E1 , E2 (designed as capacitors) connected. The voltage-variable consumer SV has a first half bridge and a second half bridge, the connection points of the respective half bridges being connected to one another via a working inductance AI. The result is a buck-boost converter, which can also be referred to as an H-bridge circuit, since there is a cross connection between the two half-bridges, which has the working inductance AI. The voltage-variable consumer designed as a voltage converter has a high-voltage output HV +, HV-. This can be followed by an accumulator, for example, in particular an accumulator that has two parts that can be configured in parallel or in series with one another.

It can be provided that the energy stores, which are designed as capacitors E1 , E2 can be charged from the low-voltage on-board network via the voltage converter, which is designed as a multi-part consumer. This voltage converter is preferably designed to be bidirectional, in particular due to the switchable rectifier on the secondary side SS that can also work as a chopper to get from the secondary SS to be able to transmit energy to the primary side. The voltage converter shown as a multi-part consumer has two transistors, each with a core K1 , K2 have the first core K1 the first primary winding P1 with the first secondary winding S2 magnetically couples, and the second core K2 the second primary winding P2 magnetic with the second secondary winding S2 couples. A controller can be provided that controls the switches of the controllable rectifiers on the secondary side SS of the relevant DC voltage converter controls as a chopper and is in particular set up to generate a predetermined precharge current with which the capacitors E1 , E2 be summoned. By precharging the capacitors E1 , E2 a high inrush current can be transferred when an external AC network is connected L1 until L3 avoid. A controller can be provided which is set up to control the DC-DC converter both in one direction and in the opposite direction.

Claims (10)

High-voltage vehicle electrical system with first and a second energy store (E1, E2) and with a configuration circuit (KS) which is set up to connect the energy stores (E1, E2) either in parallel or in series, with the high-voltage vehicle electrical system having at least one multi-part Consumer and at least one voltage-variable consumer (SV), the multi-part consumer having a first part (T1, P1; Z1) which is connected to the first energy store (E1) and has a second part (T2, P2; Z2) , which is connected to the second energy store (E2) and which is present in the multi-part consumer galvanically separated from the first part (T1, P1; Z1), furthermore the voltage-variable consumer (SV) via the configuration circuit (KV) with the first and the second energy store (E1, E2) is connected. High-voltage vehicle electrical system Claim 1 , wherein one of the at least one multi-part consumer is a multi-part electrical heating circuit (HE), the first part (T1) has at least one first heating resistor (R1), and the second part (T2) has at least one second heating resistor (R2), and the the first and the second heating resistor (R1, R2) are galvanically isolated from one another within the heating circuit (HE). High-voltage vehicle electrical system Claim 2 , wherein the first part (T1) has a control circuit set up for setting the power of the first heating resistor (R1) and the second part (T2) has a further control circuit set up for setting the power of the second heating resistor (R2). High-voltage vehicle electrical system Claim 1 , 2 or 3 , wherein the at least one multi-part consumer comprises a first and a second chopper (Z1, Z2) and a first and a second primary winding (P1, P2) of a transformer device (TR) of a DC-DC converter, the first part of the multi-part consumer being provided by the first chopper (Z1) and the first primary winding (P1), which is connected downstream of the first chopper (Z1), and the second part of the multi-part consumer is provided by the second chopper (Z2) and the second primary winding (P2), which is the second Chopper is downstream. High-voltage vehicle electrical system Claim 4 wherein the transformer device comprises a transformer with a core around which the first and second primary windings (P1, P2) associated with the transformer are wound, or wherein the transformer device (TR) comprises a first core (K1) around which the first primary winding (P1, P2) is wound, and has a second core (K2) around which the second primary winding (P1, P2) is wound. High-voltage vehicle electrical system Claim 4 or 5 , wherein the first energy store (E1) is provided as a capacitor, which is connected to the first chopper (Z1) and forms an intermediate circuit capacitor assigned to the first chopper (Z1), and the second energy store (E2) is provided as a capacitor connected to the second chopper (Z2) is connected and forms an intermediate circuit capacitor assigned to the second chopper (Z2). High-voltage vehicle electrical system Claim 4 , 5 or 6th , which further comprises at least one secondary winding (S1, S2) which is magnetically coupled to the first and the second primary winding (P1, P2), the at least one secondary winding (S1, S2) being followed by a rectifier circuit, the at least one secondary winding (S1, S2) and the rectifier circuit form a secondary side (SS), which are part of a galvanically isolating DC voltage converter, which has a primary side that contains the first and second primary windings (P1, P2) and the first and second chopper (Z1, Z2) includes. High-voltage vehicle electrical system Claim 4 , 5 , 6th or 7th , which also has a chopper control which is set up to control the first chopper (Z1) and the second chopper (Z2) offset from one another. High-voltage vehicle electrical system according to one of the preceding claims, wherein the voltage-variable consumer is a DC-DC converter which has a first side that is connected to the configuration circuit, and which has a second side that is connected to a high-voltage electrical system branch of the high-voltage vehicle electrical system. High-voltage vehicle electrical system Claim 9 , wherein the voltage-variable consumer (SV) is an inverse converter or a combination of a step-down converter and a step-up converter with a common working inductance (AI).

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