KR102492909B1 - vehicle side charging circuit - Google Patents

Abstract

The present invention is a vehicle-side charging system comprising an AC voltage interface (AC), a rectifier (PFC) connected to the AC voltage interface, one or more first and second DC voltage converters (W1, W2) and an on-board power connection (AN). It's about the circuit. The DC voltage converters are each galvanically connected and in each case comprise one or more intermediate circuit capacitors C1, C2 and one or more switching units SE1, SE2. The rectifier (PFC) is connected to the on-board power connector (AN) through the DC voltage converters (W1, W2). The charging circuit includes a switching device SV that connects the DC voltage converters W1 and W2 in a mutually switchable manner. The switching device (SV) connects the intermediate circuit capacitors (C1, C2) of the DC voltage converters (W1, W2) and the switching devices (SE1, SE2) in parallel with each other in the first switching state (1), respectively, and In the switching state (2), the intermediate circuit capacitors C1 and C2 and the switching units SE1 and SE2 are connected in series with each other, respectively.

Description

vehicle side charging circuit

[0002] Vehicles equipped with an electric drive unit have an accumulator battery to supply power to the drive unit. In many vehicles, charging sockets are provided to transfer energy from the outside into the accumulator, eg within the context of a charging process.

When a vehicle is connected to an AC voltage network, a number of electrical parameters affecting operating parameters such as voltage or power of the charging circuit may change. Such variable parameters are, for example, the number of phases that depend on the design of the AC voltage connection and the voltage or configuration of the AC voltage network, which can vary from region to region.

As such, the challenge is to present the possibility of using AC voltage connections with different characteristics in a cost-effective manner as far as possible for charging vehicles.

The problem is solved by the subject matter of claim 1. Further embodiments, features, characteristics and advantages are indicated by the dependent claims, detailed description and respective drawings.

In order to be able to match the charging circuit to the characteristics of the connection to the AC voltage network (e.g. single-phase or multi-phase), a plurality of galvanically connecting DC voltage converters are optionally connected in parallel or in series with each other by means of an adjustable switch device. A vehicle-side charging circuit that can be connected to is proposed. Thus, the charging circuit is a charging circuit that connects galvanically. Due to this feature, it is not necessary to use a transformer for galvanic electrical separation.

The rectifier of the charging circuit is connected behind the AC voltage interface of the charging circuit and rectifies the voltage applied to the AC voltage interface. The rectified voltage (or peak value) is determined by the number of phases of the AC voltage interface. In a 230 V network and three-phase connection configuration, a rectified voltage may appear that exceeds the nominal voltage limit achievable with certain semiconductor technologies. In order to provide a limiting nominal voltage for the semiconductors of the DC voltage converter, which does not limit the technology available, in this case the switch device can connect a plurality of DC voltage converters in series with each other. Due to this, the operating voltage for each DC voltage converter is divided by the number of DC voltage converters. When there are two DC voltage converters, the operating voltage for operating each of the semiconductors of the DC voltage converter is halved. In the case of single-phase operation, DC voltage converters can be connected in parallel to double the current carrying capacity.

The vehicle-side charging circuit is equipped with an AC voltage interface and a rectifier connected to it. An AC voltage interface is in particular a plug-in connection element with a plurality of contacts. The rectifier has a rectifying function, but in some embodiments, in addition to this function, it may also have other functions such as power factor correction or harmonic filter; In particular, the rectifier is an active rectifier. The rectifier has an AC voltage side. By the AC voltage side, the rectifier is connected to the AC voltage interface.

The rectifier preferably includes one or more half bridges (which may be controllable or which may be diode half bridges) for each phase contact of the AC voltage interface. The AC voltage interface may have a neutral conductor junction. This neutral conductor junction is preferably connected to the (own) half bridge of the rectifier. This half bridge is different from the half bridge which is connected with one phase of the AC voltage interface and which can in particular be a diode half bridge.

The rectifier also includes a DC voltage side. The half bridge of the rectifier is connected to the DC voltage side. The DC voltage side includes in particular two DC voltage potentials or rails. A half bridge is connected to these DC voltage potentials or rails (in this case in particular the two ends of the half bridge are connected to these potentials or rails).

Connected to the rectifier (or to the DC voltage side of the rectifier) are a plurality of DC voltage converters that are galvanically connected. The DC voltage converter is connected to the rectifier through a switch device. A switch device is provided between the DC voltage converter and the rectifier. The connection (parallel or series) in which the DC voltage converter is connected to the rectifier can be adjusted using a switch device. The switch device interconnects the switchable (in a different way) DC voltage converters. The different switching positions of the switch device are connected to different connections of the rectifier on the one hand and of the DC voltage converter on the other hand. In one switching position of the switch device, the sides of the DC voltage converter that are connected to the rectifier are connected in parallel (and in particular connected to the rectifier as a series circuit). In another switching position of the switch device, the sides of the DC voltage converter that are connected to the rectifier are connected in series with each other (and in particular connected to the rectifier as a series circuit).

By means of the switching device, the DC voltage converters (in particular the side of the DC voltage converter with intermediate circuit capacitors) can optionally be connected to each other in parallel or in series. In particular, by means of the switching device, the sides of the DC voltage converter towards the rectifier can be connected to one another in parallel or in series in an adjustable manner. These sides may correspond to the input side of the DC voltage converter, especially during the charging process. In the case of power feedback (ie bidirectional DC voltage converter), these sides correspond to the output of the DC voltage converter.

The switching device makes it possible to connect the inputs of the DC voltage converter to one another in series or in parallel (in particular with respect to the charging process). Since the DC voltage converter is connected to the rectifier, the connection between the rectifier and the DC voltage converter can thus be adjusted by means of the switching device. In the case of series connection, with two DC voltage transducers, half the operating voltage appears (based on the rectified voltage), consequently the switch element as an intermediate circuit capacitor only has this half (or divided by the number of transducers) It must be designed only according to the operating voltage. The DC voltage converter has a side facing towards the rectifier. The sides of these DC voltage converters are selectively or switchably (or adjustable) connected to each other in parallel or in series by means of a switching device. Accordingly, on these sides there are intermediate circuit capacitors that are tunably connected to each other in parallel or in series. The same situation applies also to the switch unit of the DC voltage converter.

The rectifier is connected to the onboard power connection via a DC voltage converter. The on-board power supply connection is a particularly high-voltage connection and is thus designed for operating voltages greater than 60 V, in particular corresponding to at least 400 V, 600 V or 800 V. An on-board power source with charging circuitry described herein further includes a capacitor connected to an on-board power connection. Other components besides the battery can also be connected to the onboard power connection. The on-board power connection can be connected to the DC voltage converter through a disconnect switch.

The charging circuit preferably further comprises a diode cascade. A diode cascade is provided between the DC voltage converter and the on-board power connection, in particular connected in parallel to the on-board power connection. A diode cascade involves a series circuit of diodes. This series circuit is connected in parallel to the onboard power connection. The end of the series circuit is connected to the on-board power connection (specifically to the two DC voltage potentials of the on-board power connection). At least one of the DC voltage converters is connected to the midpoint of the series circuit through which two of the diodes are connected to each other (in series). The diode cascade is specifically designed as a (single-phase) half-bridge. One of the DC voltage converters is connected to the connection point of the half bridge. When there are two or more DC voltage converters, the diode cascade includes two or more diodes. The number of DC voltage converters preferably corresponds to the number of diodes in the diode cascade. The number of connection points in a diode cascade equals the number of DC voltage converters minus one. Except for one converter, the DC voltage converter is connected with its own junction point in the diode cascade.

One of the transducers can be connected to the connection point between the two diodes of the diode cascade. One of the diodes may be connected between this converter and the other converter. The diodes of the diode cascade are connected to each other in the same direction. The forward direction of the diode points to the same potential. The same situation applies to blocking directions as well. The first and second converters each have positive potential rails, in which case these potential rails are connected to each other via a first diode. The first diode has a forward direction towards the positive potential rail of the first DC voltage converter. A second diode is connected between the positive potential rail of the second DC voltage converter and the negative potential rail of the second DC voltage converter. The second diode has a forward direction towards the positive potential rail of the second DC voltage converter (or towards the first diode or towards the positive potential rail of the first DC voltage converter).

Part or all of the DC voltage converters may each have a smoothing capacitor. The smoothing capacitor is connected in parallel to the individual DC voltage converter on the side of the DC voltage converter towards the onboard power connection.

A DC voltage converter is provided to convert the voltage received by the rectifier or by the side of the AC voltage interface in order to deliver the converted voltage to the onboard power supply connection and in particular to the diode cascade. The diode cascade adds up the voltage of the DC voltage converter (to the on-board power connection) and outputs this added voltage to the on-board power connection.

The switch units of the first and second voltage converters each include two switches or one switch and one diode connected in series. These switches are preferably semiconductor switches, for example transistors. Since the total voltage of the rectifier is divided by being divided into a plurality of DC voltage converters, a transistor with a maximum voltage of less than 650, 700 or 600 volts, for example a so-called "superjunction FET" can be used. . If the 230 volt-network is three-phase connected to the charging circuit, the same situation applies in particular to the 230-volt network, as a result of which it is not necessary to equip the DC voltage converter with transistors that must be designed for a higher maximum voltage. Due to this, the SiC-MOSFET, which represents a significant cost factor, can be omitted. As the switch unit, in particular, a transistor such as a MOSFET or also an IGBT is suitable.

One switch unit of the voltage converters (particularly the first voltage converters) may include one electronic switch and one diode. These are connected in series. The switch unit of at least one further voltage converter (in particular of the second voltage converter) may comprise two electronic switches connected in series.

The voltage converters preferably each have a series inductance. These series inductances are provided on one side of the voltage converter connected to the onboard power connection. A series inductance is provided on one side of the voltage converter where the voltage converter is connected to the onboard power connection. The switch unit of the voltage converter each has a connection point for connecting (two) switches of the associated voltage converter to each other or connecting a diode of the associated switch unit with a switch of the switch unit. Thus, a series inductance connects the switch unit of the voltage converter with the on-board power connection or with a diode cascade. Each voltage converter may have a smoothing capacitor connecting the side of the series inductance facing away from the switch unit with the potential rail of the associated DC voltage converter, in particular with the negative potential rail of the associated DC voltage converter. In other words, each DC voltage converter may have a smoothing capacitor connected in parallel on the side of the converter towards the onboard power supply connection or towards the diode cascade. This side is opposite the side of the voltage converter towards the rectifier.

The rectifier preferably has one or a plurality of switchable half bridges. The half-bridge is particularly fully switchable, ie consists of a series circuit consisting of two switches, each like a transistor. The half-bridge or the connection point or middle tap of this half-bridge is in particular connected with the AC voltage interface either directly or via a series inductance. When connected through discrete series inductances, we get a power factor correction circuit with not only a rectification function but also a voltage conversion function, especially an up conversion function. As such, the rectifier between the AC interface and the DC voltage converter is preferably an active rectifier and, if fitted with a series inductance as described, may also perform a correction function with respect to power factor and/or act as harmonic damping. can Alternatively, the rectifier is a passive rectifier, in particular a diode rectifier. The rectifier can be designed as single-phase or, preferably, as multi-phase.

The AC voltage interface can be of single-phase design or preferably is of multi-phase design, for example three-phase. Accordingly, the rectifier between the AC voltage interface and the DC voltage converter is also preferably designed as single-phase or in particular as three-phase. The number of phases of the AC voltage interface preferably corresponds to the number of phases of the rectifier connected behind the AC voltage interface. The number of phases of the AC voltage interface preferably corresponds to the number of phases of the rectifier. The number of phases of the rectifier preferably corresponds to the number of (switchable) half-bridges of the rectifier. Furthermore, an additional half bridge in the form of a diode half bridge may be provided. In this case, the rectifier comprises a small number of (switchable) half-bridges and a further half-bridge designed in particular as a diode bridge.

Hard-wired or switchable connections may be provided between the phases of the AC voltage interface. If the interface itself is only single-phase occupied or single-phase operated, these connections preferably connect all the phases to one another. Otherwise, the connection is either absent or open. If the AC voltage interface is occupied with polyphase or three phase, the connection is not provided or is open. As such, the connection enables the configuration and in particular distribution of the current to be delivered through all half-bridges of the rectifier, even if the AC interface is only occupied by a single phase. Accordingly, the AC voltage interface is equipped with a plurality of phase contacts. These phase contacts are connected to each other by means of connections in the single-phase state. In the polyphase state, the phase contacts are connected individually to the individual half-bridges, ie to the individual half-bridges of the rectifier. In the polyphase state, the phases of the AC voltage interface are not interconnected.

The connection can be provided by a semiconductor switch, an electromechanical switch or a hard-wired, removable connecting element, which is designed for example as a bridge plugged onto and removable from the pin. With the last mentioned possibility, it is possible to select the configuration in a simple and cost-effective way, without changing the rest of the circuitry to match the charging circuit to single-phase or multi-phase switching.

The switch device may include a first configuration switch and a second configuration switch. The first configuration switch connects the (preferably positive potential) voltage rail of the first voltage converter with the (preferably positive potential) voltage rail of the second voltage converter in a switchable manner. The second configuration switch preferably connects the (preferably negative potential) voltage rail of the first voltage converter with the (preferably negative potential) voltage rail of the second voltage converter in a switchable manner. The two configuration switches are assigned to different potentials of the DC voltage converter. The configuration switch may be an electromechanical or electronic switch. In one embodiment, the configuration switch is designed like the aforementioned connection.

The switch device may further include a third component switch, which may also be referred to as a disconnect switch. This switch connects the negative supply potential of the second converter switchably with the negative supply potential of the on-board power connection.

The charging circuit may further include a control unit. The control unit is connected with the configuration switch or with the switch unit. Thus, the control unit can set whether the DC voltage converters are connected in series or in parallel with each other. This allows the control unit to set, in particular, whether the sides of the DC voltage converter towards the rectifier are connected in parallel or in series with each other. Through this, the controller can set whether the current carrying capacity is doubled by the parallel connection of the rectifiers or whether individual operating voltages are divided by the series connection of the DC voltage converters according to the number of DC voltage converters. In the single-phase state, the control unit preferably controls the switch unit to connect the DC voltage converters in parallel with each other.

In the polyphase state, the control unit controls the switch unit to connect the DC voltage converters in series. This situation is particularly relevant for the series or parallel connection of the individual intermediate circuit capacitors or of the switch units of the associated DC voltage converter. If a connection is provided between the phase contacts of the switchable AC voltage interface (e.g. by a semiconductor switch or by an electromechanical switch inside the connection), then between the phases or the phase contacts if a single-phase state is provided. The same connection is made, and if polyphase conditions are provided, this connection is broken. A detection device may be provided that detects the occupancy state at the AC interface, and in particular detects whether one or a plurality of phases of the interface are occupied. If a plurality of phases are occupied, a multi-phase state is established, and if only one phase is occupied, a single-phase state is established. The detection device may be part of the control unit or may be connected in front of the control unit in order to pass corresponding information to the control unit. If the control unit is controllable (eg if the connection unit is designed as a switch unit), the control unit can be designed to control the connection. When the first switching state of the switch device (parallel connection of the voltage converters) is present, the control unit is designed to control the third configuration switch or disconnect switch in the closed state. When the second switching state of the switch device (series connection of the voltage converters) is present, the control unit is designed to control the third configuration switch or disconnect switch in the open state. The first and second configuration switches are closed in the first switching state and open in the second switching state. The control unit is designed to control this situation and is in particular connected in a control way with the configuration switch.

The switch device preferably comprises a series switch. This series switch connects the intermediate circuit capacitor and the switch unit in series with each other in the closed state. In the first switching state of the switch device, the series switch is open. In the second switching state of the switch device, the series switch is closed. For parallel connection (in the first switching state), first and second component switches are used, which can also be referred to as parallel switches. In the first switching state of the switch device, the first and second component switches are closed (for parallel connection of the voltage converters). In the second switching state, the first and second configuration switches are open (for series connection of voltage converters using series switches).

If a single-phase condition exists at the AC interface (eg in a single-phase occupation situation of the AC interface), the switch device is preferably in a first switching state (of the switching device). If a polyphase state exists at the AC interface (eg in a multiphase occupation situation of the AC interface), the switch device is preferably in the second switching state (of the switching device).

However, there may be other controllers than the controller. A second switching state of the switching device may be provided in a single-phase state (ie, a single-phase occupied or single-phase set state of the AC interface). In this case, less rectified voltage appears (compared to the polyphase condition), where the voltage converters are connected in series, for example in a specific voltage range at the on-board power connection or in the desired power flow mode. Also, in a multi-phase state (ie, a multi-phase occupation or multi-phase setting state of the AC interface), the first switching state of the switching device may be provided. In this case, a higher rectified voltage appears (compared to the single-phase condition at the AC interface), where the voltage converters are connected in parallel for other specified voltage ranges, for example at the on-board power connection or in the desired power flow mode.

The first and second constituent switches on the one hand and the serial switches on the other hand are alternately controlled. When the first and second configuration switches are closed, the series switch is open. When the series switch is closed, the first and second component switches are open. The control unit is designed to correspondingly control the switch or switch device. A series switch is part of a switch device. The third component switch may be part of the switch device, but may also form a component external to the switch device. The third configuration switch preferably has the same switching position as the first and second configuration switches.

A control unit, a part of the control unit or a control unit connected directly or indirectly may be provided for controlling the DC voltage converter or the switch of this converter and/or (if designed as an active rectifier) the switching device of the rectifier. can A control unit connected in a control manner with the switch unit can be arranged by means of a higher level control unit connected in a control manner also with a control unit which controls the switch unit of the DC voltage converter and/or the switching element of the rectifier. However, the classification of control units may ultimately be realized in various ways.

The rectifier may have a diode half bridge coupled with the neutral conductor contact of the AC voltage interface. In addition to diode half-bridges, the rectifier comprises half-bridges with switch units, in which case each such half-bridge is assigned a phase of an AC voltage interface or each such half-bridge (via an inductance, for example) is connected to an AC voltage It is related to the topology of the interface.

The rectifier may comprise one or preferably a plurality of half-bridges, each of which comprises a series circuit consisting of two switching elements or diodes. The rectifier can be designed as an active power factor correction filter or it can be designed as a passive rectifier. When the rectifier is designed as an active rectifier, it includes a plurality of half-bridge circuits coupled with the AC interface through series inductors. In this case the connections are discrete, so that the series inductance also makes a discrete connection between the individual half-bridges and the phase contacts of the AC voltage interface. As mentioned, for single-phase charging or in a single-phase state, it can be proposed that the phase contacts are connected to one another via corresponding connections. The rectifier can in particular be designed as a Vienna-rectifier.

The switch of the switch unit is preferably a semiconductor switch, and may include transistors such as MOSFETs and IGBTs. It can be proposed that each switch of the switch unit comprises two semiconductor switches (e.g. transistors), in particular if these semiconductor switches have reverse diodes, these semiconductor switches are connected to each other in an anti-series manner. .

1 is used to explain the charging circuit described herein in more detail.

1 shows an on-board power system with an exemplary charging circuit connected (statically) to a current network (SN) via an AC voltage interface (AC). In this case, the supply current network is designed as a three-phase, in particular a common current supply network. The charging circuit includes an AC voltage interface (IF) connected to a rectifier (PFC). The rectifier is again connected to two DC voltage converters (W1, W2). These transducers are connected to each other in a configurable manner via a switch device (SV).

At switch position 1, DC voltage converters W1 and W2 are connected in parallel to each other by means of a switch device SV. Such a situation arises in particular on the capacitors C1 and C2 of the DC voltage converters W1 and W2 or the switching units SE1 and 2 of these converters or, in other words, on the side of these converters towards the rectifier PFC (input can also be regarded as). The switching position 1 corresponds to the first switching state of the switch device SV.

The first DC voltage converter W1 includes a half bridge including a first switch S1 and a diode S2. Accordingly, the half bridge of the DC voltage converter W1 is a half controlled half bridge. DC voltage converter W1 is connected to the positive current rail (+) leading to rectifier PFC. The second DC voltage converter W2 includes a half bridge including a third switch S3 and a fourth switch S4. Thus, the half bridge of the DC voltage converter W2 is a fully controlled half bridge. DC voltage converter W2 is connected to the negative current rail (-) leading to rectifier PFC.

Therefore, the first DC voltage converter (W1) is connected to the positive supply potential (V+). The positive supply potential of the first DC voltage converter W1 corresponds to the positive supply potential V+ of the charging circuit. The second supply potential of the first DC voltage converter W1 may be selectively connected to the positive supply potential of the second DC voltage converter W2 or with another supply potential V- of the charging circuit via a switch device SV. can Through this, it can be selected whether the two DC voltage converters W1 and W2 should be switched in series or in parallel with each other.

The second DC voltage converter W2 has a negative supply potential corresponding to the negative supply potential V- of the charging circuit. However, the second DC voltage converter W2 also has a potential, that is to say a positive supply potential that can be selectively connected in various ways to the first DC voltage converter W1 via the switch device SV. . The positive supply potential of the second DC voltage converter W2 can be connected with the negative supply potential of the first converter W1 (corresponding to the second switching state, series connection) or the positive supply potential V+ of the charging circuit It can be connected with (first switching state, corresponding to parallel connection).

The switch device SV includes first and second configuration switches KS1 and KS2 and a series switch SS. In addition, the switch device SV includes a third configuration switch KS3. In the first switching state 1, the configuration switches KS1, KS2 and KS3 are closed. In the first switching state 1, the voltage converters W1 and W2 and in particular the individual supply potentials of these converters are connected in parallel. Also, the individual switch units SE1 and SE2 are connected in parallel in the first switching state (1). The same situation applies to the intermediate circuit capacitors C1 and C2 of the DC voltage converters W1 and W2. The third configuration switch KS3 connects the negative voltage potential of the second voltage converter W2 to the negative potential DC- or a contact of the on-board power supply connection unit AN. In the switching state 1, the negative voltage potential of the second voltage converter W2 corresponds to the negative voltage potential of the first voltage converter W1, because the configuration switch KS2 converts these potentials {switching state This is because in (1) } connects. In the switching state (1), the configuration switch KS2 connects the negative potential or current rails of the voltage converters W1 and W2 to each other. In the switching state (1), the configuration switch KS1 connects the positive potential or current rails of the voltage converters W1 and W2 to each other.

In the illustrated switching state 2 of the switch device SV, the configuration switches KS1 and KS2 are open. The third configuration switch KS3 is also open in the switching state (2). However, in the switching state (2) the series switch (SS) is closed. Due to this, the DC voltage converters W1 and W2 are connected in series with each other. In switching state 2, the series switch SS connects the negative potential or negative current rail of the first converter W1 with the positive potential or positive current rail of the second converter W2. The current rails and potentials of the converters referred to herein relate in particular to the current rails to which the individual intermediate circuit capacitors C1 , C2 are connected in parallel or which bridge the individual switch units SE1 , SE2 .

In switching state 1, opposite to the shown switching state, series switch SS is open and switches KS1 to KS3 are closed. Due to this, the voltage converters W1 and W2 are each directly connected to the rectifier GR in the switching state (1). In other words, when switching state 1 is provided, the DC voltage converters W1 and W2 are connected in parallel with each other. The switches KS1 to KS3 are open or closed at the same time. When the switches KS1 to KS3 are closed, the switch SS is open. When the configuration switches KS1 to KS3 are open, the switch SS is closed. Thus, the switch SS on the one hand and the switches KS1, KS2 and KS3 on the other hand preferably operate in a complementary manner (depending on their switching state). Situations like this are particularly related to the active state of the circuit; In the inactive state of the circuit, the switches KS1 to KS3 and SS may be open.

The two DC voltage converters W1 and W2 each include one intermediate circuit capacitor C1 or C2. The first DC voltage converter (W1) has an intermediate circuit capacitor (C1). The second DC voltage converter (W1) has an intermediate circuit capacitor (C1). Intermediate circuit capacitors are each connected in parallel to the supply potential of the individual DC voltage converters. What has been said about the intermediate circuit capacitor also applies to the switch units SE1 and SE2.

The DC voltage converter W1 has a switch unit SE1. This switch unit comprises a series circuit consisting of a switch S1 (eg implemented as a transistor) and a diode S2. The diode S2 is connected to the negative potential of the first DC voltage converter W1. The connection point between diode S2 and switch S1 is connected with series inductance L1. The first series inductance L1 connects the first switch unit SE1 to the onboard power connection AN (in particular the positive contact DC+) and to a diode cascade DK, in particular to one end of the diode cascade. The connection point of the switch unit (SE1) is connected to the first end of the series inductance (L1), and the second end of the series inductance (L1) is connected to the on-board power connection (AN) or the positive potential or contact (DC+) of this connection. ) is connected to

The DC voltage converter W2 has a switch unit SE1. This switch unit comprises a series circuit composed of a second switch S3 (eg implemented as a transistor) and a third switch S4 (eg implemented as a transistor). The third switch S4 is connected to the negative potential of the second DC voltage converter W2. The second switch (S3) is connected to the positive potential of the second DC voltage converter (W2). The connection point between the second and third switches S2 and S4 is connected to (another) series inductance L2. This inductance is the series inductance L2 of the second DC voltage converter W2. The second series inductance L2 connects the second switch unit SE2 to a connection point inside the diode cascade DK. The diode cascade DK includes first and second diodes D1 and D2 connected to each other through connection points. Diodes D1 and D2 are connected in series. The diodes D1 and D2 of the diode cascade each have a blocking direction toward the positive potential (+) side of the connection portion AN. The connection point of the switch unit SE1 is connected to the first end of the series inductance L2, and the second end of the series inductance L2 is connected to the connection point of the diode cascade DK.

Each of the voltage converters W1 and W2 includes smoothing capacitors GK1 and GK2. The smoothing capacitor GK1 of the voltage converter W1 is connected behind the series inductance L1 and is connected in parallel. The smoothing capacitor GK2 of the voltage converter W2 is connected after the series inductance L1 and is connected in parallel. The smoothing capacitor GK1 connects the positive potential (DC+) of the onboard power connector AN to the negative potential of the first voltage converter W1. The smoothing capacitor GK2 connects the negative potential of the second voltage converter W2 with the connection point of the diode cascade or the series inductance L2 of the second converter W2.

In summary, the switch device SV and the division into two DC voltage converters W1 and W2 allow configurable combinations of voltage converters. In this case, the switch SS can be regarded as a series switch (since the DC voltage converter is connected in series when the switch S1 is closed). The configuration switches KS1 and KS2 can be regarded as parallel switches, since when the configuration switches KS1 and KS2 are closed, the DC voltage converters W1 and W2 are connected in parallel with each other. On the one hand, the switching state of the switch SS and the switches KS1 and KS2 and the switching state of the configuration switch KS3 are reversed. Switch KS1 is assigned to a positive supply potential, and switch KS2 is assigned to a negative supply potential. However, it may also be provided that all switches are open, eg in inactive mode or faulty mode.

The vehicle on-board power supply may include a charging circuit (particularly the charging circuit shown) and an on-board power supply section connected to the charging circuit. The on-board network section comprises one or more accumulators A, and may further comprise one or more (vehicle-side) loads and/or one (vehicle-side) electrical energy source. This on-board network section will be connected to the charging circuit on the right as shown in FIG. 1 , for example to connection AN.

The storage battery A may be connected to the on-board power connector AN of the charging circuit indicated by the contacts DC+ and DC-. Accumulator battery A is not in particular part of the charging device, rather the charging device is terminated either by the contacts (DC+, DC-) of the on-board power connection AN or by the on-board power connection itself.

The control unit CT is connected in a control manner with the configuration switches KS1 to KS3 and the series switch SS as symbolically shown. The same or different control units may be provided to control the switch units SE1 and SE2.

Claims (10)

As a vehicle-side charging circuit,
- AC voltage interface (AC);
- a rectifier (PFC) connected to said AC voltage interface;
- at least one first and second DC voltage converters (W1, W2) each galvanically connected and each comprising at least one intermediate circuit capacitor (C1, C2) and at least one switch unit (SE1, SE2), and
- Including the onboard power connection (AN),
The rectifier (PFC) is connected to the on-board power connector (AN) through DC voltage converters (W1, W2), and the charging circuit is a switch device (SV) that connects the DC voltage converters (W1, W2) in a mutually switchable manner. Including, the switch device (SV) connects the intermediate circuit capacitors (C1, C2) in parallel with each other in the first switching state (1), and the switch units (SE1, SE2) of the DC voltage converters (W1, W2) In addition, the switch device (SV) connects the intermediate circuit capacitors (C1, C2) in series to each other in the second switching state (2), and connects the switch devices (SE1, SE2) to each other in series. , the vehicle-side charging circuit. The vehicle-side charging according to claim 1, further comprising a diode cascade (DK) connected in parallel to the on-board power connection (AN) between the DC voltage converter (W1, W2) and the on-board power connection (AN). Circuit. 3. The method of claim 2, wherein one converter (W2) of said converters is connected to a connection point between two diodes (D1, D2) of a diode cascade (DK), and one of said diodes (D1) ) is connected between the converter (W2) and another converter (W1), the vehicle-side charging circuit. The switch unit of claim 1, wherein the switch unit (SE1) of the first voltage converter (W1) includes an electronic switch (S1) and a diode (S2) connected in series, and the switch unit of the second voltage converter (W1) (SE2) is a vehicle-side charging circuit, including two electronic switches (S3, S4) connected in series. The method of claim 1, wherein the voltage converters (W1, W2) each have one series inductance (L1, L2) provided on one side of the voltage converter (W1, W2), and the voltage converter (W1, W2) on the one side ) is connected to the on-board power connection (AN), vehicle-side charging circuit. 6. The method according to any one of claims 1 to 5, wherein the switch device (SV) includes a first configuration switch (KS1) and a second configuration switch (KS2), the first configuration switch (KS1) The voltage rail of the positive potential of the first voltage converter W1 is switchably connected to the voltage rail of the positive potential of the second voltage converter W2, and the second configuration switch KS2 is connected to the first voltage converter W1. A vehicle-side charging circuit that switchably connects a voltage rail of negative potential of ) to a voltage rail of negative potential of the second voltage converter (W2). 6. The method of any one of claims 1 to 5, wherein the switch device (SV) connects the negative supply potential of the second converter (W2) to the negative supply potential (DC-) of the on-board power connector (AN). A vehicle-side charging circuit having a disconnect switch (KS3) connected in a switchable manner. 6. A series switch according to any one of claims 1 to 5, wherein the switch device (SV) connects the intermediate circuit capacitors (C1, C2) and the switch units (SE1, SE2) in series with each other in a closed state. SS), a vehicle-side charging circuit. 6. The vehicle-side charging circuit according to any one of claims 1 to 5, wherein the AC voltage interface (AC) is designed as single-phase or multi-phase. 6. Vehicle-side charging circuit according to any one of claims 1 to 5, wherein the rectifier (PFC) is designed as an active rectifier or as an active power factor correction filter.

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