Vehicle charging circuit with rectifier device, intermediate circuit capacitor and pre-charge / discharge circuit
By introducing a rectifier device, an intermediate circuit capacitor, and a pre-charge/discharge circuit into the vehicle charging circuit, and using a changeover switch to control the circuit connection, the safety issues of the vehicle charging connector and capacitor under dangerous voltages are solved, and the safe and reliable operation of the circuit is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- VTESCO TECH GMBH
- Filing Date
- 2021-12-03
- Publication Date
- 2026-05-22
Smart Images
Figure CN116648371B_ABST
Abstract
Description
Technical Field
[0001] Vehicles with electric drive systems are often equipped with high-voltage batteries that can generate voltages that are dangerous to humans. Furthermore, components with energy storage devices, such as capacitors, are present in such vehicles. These components can be charged using the battery voltage or the rectified grid voltage from a charging station, and are therefore also potentially dangerous to humans. Background Technology
[0002] On the one hand, there is interest in preventing dangerous contact voltages on the charging connector when it is not occupied. On the other hand, there is interest in avoiding dangers caused by high contact voltages, which could arise, for example, from unprotected contacts or from malfunctions in a rear-end collision with a vehicle that is being charged. Summary of the Invention
[0003] Therefore, the object of the present invention is to provide a feasible solution that enables protection against dangerous contact voltages, particularly in the case of exposed contacts or rear-end collisions with vehicles that are charging, and also in the case of storage devices such as capacitors that can carry dangerous voltages in addition to batteries.
[0004] This task is accomplished by a vehicle charging circuit according to claim 1. Other features, characteristics, embodiments, and advantages will become apparent from the dependent claims, the specification, and the drawings.
[0005] It is recommended that the vehicle charging circuit be equipped with a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit. The pre-charge / discharge circuit has a switch (commonly referred to as the "first switch") that selectively connects one terminal of the intermediate circuit capacitor to the rectifier device for pre-charging or to the other terminal for discharging. Using this switch, which selectively connects one terminal of the intermediate circuit capacitor to the rectifier or to a discharge resistor, the rectifier circuit cannot be connected to the discharge resistor even in the event of erroneous operation, as determined by the structure of the switch. This avoids the rectifier being connected to the discharge resistor and thus permanently exposing the discharge resistor to voltage in the event of incorrect or delayed disconnection from the charging station or a defective switch. In particular, it prevents the discharge resistor from overheating and malfunctioning due to the energy of the rectifier and the corresponding continuous current flow.
[0006] The changeover switch connects the intermediate circuit capacitor to the discharge resistor instead of the rectifier in the uncontrolled state, thereby preventing current flow from the rectifier in the event of control failure. This also helps to suppress defective, continuous current from the rectifier unit and, in particular, enables functional separation of the rectifier unit from downstream components such as the intermediate circuit capacitor and other components.
[0007] Three different variations of the circuit connection for the switching switch and discharge resistor are illustrated exemplarily in this regard, wherein Figures 1 to 3 It belongs to the first variant scheme. Figure 4 , 5 And 8 belong to the second variant scheme, and Figure 6 and 7 Used to explain the third variant.
[0008] A vehicle charging circuit is generally described, comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit. This vehicle charging circuit is particularly located in a vehicle (in the sense of a vehicle-side charging circuit), for example, in the vehicle's onboard electrical network; however, it can also be located in a charging station.
[0009] The vehicle charging circuit and its components are specifically designed for voltages exceeding 60 volts, for example, for rated voltages of at least 100, 200, 400, or 800 volts. The vehicle charging circuit is particularly configured to charge the vehicle's traction battery, which is designed according to one of the aforementioned voltages. DC-DC voltage converters, for example, leading to the battery or to a battery terminal, can be connected to intermediate circuit capacitors.
[0010] The precharge / discharge circuit has at least one first switching switch configured to connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position. This allows for a direct connection, i.e., without a (current-limiting) resistive element between the intermediate circuit capacitor and the rectifier device, to guide the charging current. In a second position, the switch connects the first terminal of the intermediate circuit capacitor to the second terminal of the intermediate circuit capacitor via a discharge resistor. Thus, when the second position is present, the discharge resistor allows a limited current flow for discharging the intermediate circuit capacitor. The concept of a "discharge resistor" implies that it is designed for discharging, but this does not preclude other functions such as precharging.
[0011] Finally, the changeover switch is configured to occupy the second switch position in a non-operated state. In this state, the first changeover switch allows connection of the intermediate circuit capacitor through the discharge resistor and thereby allows restricted current flow for discharging the intermediate circuit capacitor (and, if necessary, pre-charging the intermediate circuit capacitor, see the third variant).
[0012] The first changeover switch is preferably constructed as an electromechanical changeover switch. This electromechanical changeover switch has an intermediate connector. The intermediate connector is connected to an intermediate circuit capacitor, particularly to the first terminal, for example, the positive terminal, of the intermediate circuit capacitor. The changeover switch can selectively connect to either a first or second contact of the changeover switch, wherein the changeover switch is specifically constructed such that the intermediate connector is not simultaneously connected to both contacts and the two contacts of the changeover switch cannot be connected to each other at any time. The discharge resistor can be directly connected to the first contact, i.e., via a switchless connection, or indirectly, i.e., via another second changeover switch. The second contact is directly, i.e., preferably switchless, or indirectly, i.e., via a second changeover switch, connected to a rectifier device, particularly via the already mentioned rectifier. In the unoperated state of the changeover switch, the intermediate connector is connected to the second contact.
[0013] Therefore, in the uncontrolled state, the selector switch is in the second switch position. The selector switch is particularly configured as a relay, wherein preferably, in the uncontrolled state, a spring force or similar force presses the intermediate connector against and electrically connects it to the second contact. Here, it is particularly possible to provide a movable contact element that is electrically connected to the intermediate connector (regardless of the state of the selector switch) and that this contact element is connected to either the first or second contact depending on the state of the selector switch. This prevents connection between the two contacts or simultaneous connection of the intermediate connector to both contacts. The second selector switch can be configured in the same manner as the first switch. However, the second selector switch is preferably connected to the vehicle charging circuit in a different manner than the first selector switch.
[0014] A DC-DC voltage converter can be connected after the intermediate circuit capacitors. This converter is part of the vehicle charging circuit. For multiple intermediate circuit capacitors, the same DC-DC voltage converter can be connected after two of them. These intermediate circuit capacitors can be connected in series directly or via a configuration circuit that adjusts whether they are connected in series or in parallel.
[0015] Another aspect is that the rectifier device is configured as a passive rectifier, but preferably as an active rectifier, and particularly preferably as a power factor correction (PFC) filter. In particular, the power factor correction circuit is referred to as a power factor correction filter, which is configured to actively correct the current shape and the phase of the current relative to the input voltage. The rectifier circuit can be configured in single-phase or multi-phase configuration and can have AC voltage terminals, which are correspondingly configured in single-phase or multi-phase configuration. In particular, the rectifier device is configured in three-phase configuration, but is designed for both single-phase and three-phase operation.
[0016] According to a first variant, the first changeover switch is configured to connect, in a first position, the first terminal of the intermediate circuit capacitor to the rectifier device, particularly its first potential. Here, the pre-charge / discharge circuit includes a pre-charge resistor and a switch. This switch is configured as a normally closed contact or (preferably) a normally open contact. The switch is connected in parallel with the pre-charge resistor. If the switch is closed, it bridges the pre-charge resistor (and particularly only the charging resistor). If the switch is open, the pre-charge resistor restricts the current flow between the intermediate circuit capacitor and the rectifier. The switch or pre-charge resistor is connected between the first changeover switch and the rectifier device and preferably forms a unique connection between the changeover switch and the first potential (e.g., a positive potential) of the rectifier device. In other words, the first changeover switch is connected to the first potential of the rectifier device through a parallel circuit formed by the pre-charge resistor and the first changeover switch.
[0017] The switch is preferably configured as a normally open contact and thus disconnected in the uncontrolled state; however, it can also be configured as a normally closed contact. If the vehicle charging circuit has only one and not multiple such pre-charge / discharge circuits, then the vehicle charging circuit preferably also includes only one intermediate circuit capacitor. Furthermore, in this case, the rectifier device is configured as a single phase. Additionally, it is also preferably provided that only one DC-DC voltage converter is provided, which is connected after the intermediate circuit capacitor. The switch can also be considered a second changeover switch, which is closed in the first position and across the pre-charge resistor, and in the second position establishes a connection with the unconnected contacts and is thus disconnected. The second changeover switch is also preferably configured to occupy the second switch position in the uncontrolled state.
[0018] Another embodiment of this first variant includes multiple pre-charge / discharge circuits and multiple intermediate circuit capacitors, particularly two intermediate circuit capacitors. In this embodiment, a neutral conductor terminal and two of the pre-charge / discharge circuits and two of the intermediate circuit capacitors are also preferably provided. These pre-charge / discharge circuits are configured as described above. The connection within the vehicle charging circuit is described below. In this embodiment, the intermediate circuit capacitors are connected to each other via a midpoint. This midpoint is preferably connected to the neutral conductor terminal, wherein for a rectifier device configured as a Vienna rectifier, this connection to the neutral conductor terminal can be omitted or can have a symmetrical regulator. The rectifier device also has a neutral conductor terminal and is preferably configured in three phases. The neutral conductor terminal of the rectifier device is particularly connected to the midpoint between the two intermediate circuit capacitors. The two pre-charge / discharge circuits and the intermediate circuit capacitors are symmetrically connected about the midpoint or the neutral conductor terminal and connected to different potentials of the rectifier device. The first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between the first potential of the rectifier device and the first intermediate circuit capacitor in the intermediate circuit capacitor. The first potential can be a positive potential of the rectifier device, particularly a positive potential on the DC voltage side of the rectifier device. The second pre-charge / discharge circuit is preferably connected between the second potential of the rectifier device and the second intermediate circuit capacitor. The second potential is preferably a negative potential of the rectifier device, particularly a negative potential on the DC voltage side of the rectifier device. The discharge resistors of the two pre-charge / discharge circuits are preferably connected to each other through a midpoint. Therefore, the two discharge resistors are connected to a neutral conductor terminal. The two pre-charge resistors and the switches connected in parallel with them, i.e., the two parallel circuits of the two pre-charge / discharge circuits, are connected to different potentials of the rectifier device. A first parallel circuit of the pre-charge resistors in the first potential connection between the first potential and the first intermediate circuit capacitor, and a second parallel circuit of the pre-charge resistors and switches in the second potential bus, which connects the second potential of the rectifier device to the second intermediate circuit capacitor, are generated. In this embodiment, the rectifier device is configured in a three-phase configuration, i.e., it has three individual phase terminals and preferably also a neutral conductor terminal. The rectifier device can also be configured without a neutral conductor terminal; however, it is preferred that the intermediate point is connected to the neutral conductor terminal of the vehicle charging circuit.
[0019] In the aforementioned embodiment, the two intermediate circuit capacitors are directly interconnected via a connection point. However, another embodiment specifies that these intermediate circuit capacitors are interconnected via a configuration circuit. This configuration circuit is preferably also connected to the neutral conductor terminal of the vehicle charging circuit, which can also be connected to an optional neutral conductor terminal of the rectifier device. The configuration circuit connects the intermediate circuit capacitors to each other and is configured for selective parallel or series connections of the intermediate circuit capacitors. For other embodiments and variations, it is also applicable that the configuration circuit, for example, can have two changeover switches and two diodes, which are connected in series via a diode connection point. This diode connection point is connected to the neutral conductor terminal of the vehicle charging circuit and may also be optionally connected to the rectifier device. The changeover switches selectively connect the intermediate circuit capacitors directly and in series with each other, or connect the two intermediate circuit capacitors to the potential of the rectifier device, such that the two capacitors are connected in parallel with each other and connected in parallel to the two potentials of the rectifier device.
[0020] If a configuration circuit is provided, the rectifier device is preferably configured in a three-phase configuration. If multiple intermediate circuit capacitors are provided, the rectifier device can also be configured in a three-phase configuration. A control device can be provided that can selectively operate the rectifier device in single-phase or three-phase operation, and this control device is preferably also connected to the configuration circuit. In single-phase operation, the control device preferably operates the configuration circuit to connect the capacitors in parallel, and in the three-phase state of the rectifier device, the control device operates the configuration circuit to connect the intermediate circuit capacitors in series. Thus, compared to single-phase operation, three-phase operation, which results in a higher output DC voltage for the rectifier device, generates half the output voltage for each intermediate circuit capacitor, while in single-phase operation, the capacitances of the two capacitors in parallel are added, and the higher ripple of the rectified voltage compared to three-phase operation is thus better smoothed. In series operation, the two intermediate circuit capacitors only receive half of the output voltage, thus allowing the intermediate circuit capacitors to be designed with a lower rated voltage or to use a higher input voltage while keeping the capacitors' rated voltages the same.
[0021] This describes a first embodiment of the first variant, which has only a single pre-charge / discharge circuit and a single intermediate circuit capacitor, wherein the rectifier device is preferably configured as a single phase. The second and third embodiments of the first variant provide multiple pre-charge / discharge circuits and multiple intermediate circuit capacitors connected in series, while the third embodiment of the first variant provides intermediate circuit capacitors connected via a configuration circuit capable of selectively connecting the intermediate circuit capacitors in series or in parallel.
[0022] The second variant specifies that the pre-charge / discharge circuit of the vehicle charging circuit includes a second switch in addition to the first switch. In the first switch position, the second switch is not connected to the first switch. In the second switch position, the first switch connects the first terminal of the intermediate circuit capacitor to the second switch. The second switch is configured to: connect the first switch to the first potential of the rectifier device via a pre-charge resistor in the first position, and connect the first switch to the second terminal of the intermediate circuit capacitor via a discharge resistor in the second position. In other words, a discharge resistor and a pre-charge resistor are provided as another resistor, wherein the second switch is used to selectively connect the first switch to either the pre-charge resistor or the discharge resistor. Therefore, selection between a discharge mode and a pre-charge mode is possible by means of the second switch. Here, the first changeover switch is used to select whether a direct connection should exist between the rectifier device and the intermediate circuit capacitor, or whether pre-charging or discharging should be performed. Therefore, the intermediate circuit capacitor is connected to one of the two mentioned resistors via the second changeover switch, and thus there is no direct, resistorless connection between the intermediate circuit capacitor and the first potential of the rectifier device. In this variant, and in all variants with a pre-charging resistor separate from the discharge resistor, the discharge resistor can be designed for higher power than the pre-charging resistor. This enables rapid discharge, which is particularly important for safety, while the pre-charging resistor can be designed with a lower rated power or maximum power and thus can be constructed in a cost-effective manner.
[0023] The first embodiment of this (second) variant specifies that only one pre-charge / discharge circuit and only one intermediate circuit capacitor are provided. In this case, the rectifier device is preferably configured as a single phase. If a DC-DC voltage converter is provided, it is preferable that there is only one DC-DC voltage converter connected after the single intermediate circuit capacitor. The following describes an embodiment of this second variant, in which multiple intermediate circuit capacitors and multiple pre-charge / discharge circuits are provided.
[0024] The first embodiment of the second variant includes a plurality of intermediate circuit capacitors connected in series. Specifically, two intermediate circuit capacitors are connected to each other via a connection point, which can be connected to the neutral conductor terminal of the vehicle charging circuit. This connection point can also optionally be connected to the neutral conductor terminal of the rectifier device. The two pre-charge / discharge circuits (and the two intermediate circuit capacitors) are associated with different potentials of the rectifier device. The first pre-charge / discharge circuit is connected between the first potential of the rectifier device and the first intermediate circuit capacitor. The second pre-charge / discharge circuit is preferably connected between the second potential of the rectifier device and the second intermediate circuit capacitor. The first potential is preferably a positive potential (= positive potential) of the rectifier device or the DC voltage side of the rectifier device, and the second potential is a negative potential (= negative potential) of the rectifier device or the DC voltage side of the rectifier device. The discharge resistors of the two pre-charge / discharge circuits are connected to each other, particularly via a midpoint. The two pre-charge resistors connect the corresponding second switching switches of the pre-charge / discharge circuit to different potentials of the rectifier device. The vehicle charging circuit is equipped with a pre-charge / discharge circuit and intermediate circuit capacitors, which are symmetrically connected relative to the neutral conductor terminal or the connection point between intermediate circuit capacitors. For multiple intermediate circuit capacitors, these capacitors preferably have the same capacitance and are preferably designed to operate at the same voltage.
[0025] Following the second embodiment described above, which features a fixed connection, i.e. a series connection, of the intermediate circuit capacitors, the third embodiment of the second variant is described below, which includes a configuration circuit.
[0026] In a third embodiment of the second variant, a configuration circuit is provided through which the two intermediate circuit capacitors are interconnected. The configuration circuit is configured to selectively connect the intermediate circuit capacitors in parallel or series. In particular, there is a neutral conductor connector of the vehicle charging circuit. It is preferably connected to the configuration circuit. The configuration circuit here corresponds to the configuration circuit described above.
[0027] As in the second embodiment of the second variant, in the third embodiment of the second variant, the first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between the first potential of the rectifier device and the first intermediate circuit capacitor in the intermediate circuit capacitor. The second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between the second potential of the rectifier device and the second intermediate circuit capacitor in the intermediate circuit capacitor. The discharge resistors of the two pre-charge / discharge circuits are connected to each other via a configuration circuit. This is achieved by connecting the intermediate circuit capacitors to each other via a configuration circuit and connecting the respective pre-charge / discharge circuits in parallel to the respective intermediate circuit capacitors. The two pre-charge resistors connect the respective second switching switches of the pre-charge / discharge circuits to different potentials of the rectifier device.
[0028] In a third embodiment, the rectifier device is specifically designed for single-phase and three-phase operation, wherein the configuration circuit is arranged in parallel connection in single-phase operation and in series connection in three-phase operation.
[0029] The third variant specifies that the pre-charge / discharge circuit, or each pre-charge / discharge circuit, has a second switching switch connected to the first switching switch via a discharge resistor. Here, the second switching switch selectively connects the discharge resistor to a rectifier device for pre-charging or to an intermediate circuit capacitor for discharging the intermediate circuit capacitor. As in the second variant, the first switching switch is configured to either selectively establish a direct connection between one intermediate circuit capacitor and the other rectifier device, or establish a pre-charge or discharge path via the second switching switch. Here, the second switching switch selects whether the same resistor is connected to the rectifier device or the intermediate circuit capacitor. Here, the (at least one) pre-charge / discharge circuit has a second switching switch in addition to the first switching switch. The first switching switch is configured to connect the first terminal of the intermediate circuit capacitor to the second switching switch via the discharge resistor in a second position, and the second switching switch is connected to the second terminal of the intermediate circuit capacitor. The second switching switch is configured to connect the discharge resistor to a first potential of the rectifier device in a first position.
[0030] Thus, the discharge resistor acquires the additional function of pre-charging, wherein, as mentioned, the second changeover switch is used to set the function of discharging or pre-charging. In the second position, the second changeover switch connects the first changeover switch to the second terminal of the intermediate circuit capacitor through the discharge resistor. This generates a discharge function for the intermediate circuit capacitor. This can also be generated by the pre-charge / discharge resistor due to its dual function. If the rectifier device is configured as a single phase, it is preferable to also provide only one pre-charge / discharge circuit and the (single) intermediate circuit capacitor is connected in parallel to the two potentials of the rectifier device.
[0031] In another embodiment, the vehicle charging circuit is equipped with one or two pre-charge / discharge circuits, wherein in these embodiments the rectifier device is preferably configured for three-phase operation (in addition to single-phase operation mode if necessary).
[0032] Therefore, the second embodiment of the third variant specifies the presence of two pre-charge / discharge circuits and two intermediate circuit capacitors. The intermediate circuit capacitors are interconnected via a midpoint. This midpoint can be connected to the neutral conductor terminal of the vehicle charging circuit. The first pre-charge / discharge circuit is connected between the first potential of the rectifier device and the first intermediate circuit capacitor. The second pre-charge / discharge circuit is connected between the second potential of the rectifier device and the second intermediate circuit capacitor. The second switching switches of the two pre-charge / discharge circuits are interconnected via the midpoint. This is achieved by the fact that the intermediate circuit capacitors are also interconnected via midpoints, and the corresponding pre-charge / discharge circuits are connected in parallel to their respective intermediate circuit capacitors.
[0033] The two first switching switches connect the corresponding discharge resistors of the relevant pre-charge / discharge circuits to different potentials of the rectifier device. Here, compared to a single-phase implementation or a vehicle charging circuit with only one pre-charge / discharge circuit and only one intermediate circuit capacitor, a pre-charge / discharge circuit is provided in each of two potential buses, wherein the potential buses connect the intermediate circuit capacitor to the rectifier device.
[0034] The third embodiment of the third variant does not involve a rigid series connection between the intermediate circuit capacitors, but rather a connection via a configuration circuit. This configuration circuit is configured to selectively connect the intermediate circuit capacitors in parallel or in series. An optional neutral conductor terminal is connected to the configuration circuit. Here, if the rectifier device operates in single-phase mode (in single-phase operation), the configuration circuit is preferably configured to connect the intermediate circuit capacitors in parallel, and if the rectifier device is operating in three-phase mode, the configuration circuit establishes a series connection between the capacitors.
[0035] The implementation of the third variant allows the use of the same resistor to generate both discharge and charge functions. This is particularly possible because the discharge and pre-charge phases are typically not adjacent and occur relatively frequently, thus preventing the resistor from overheating in the corresponding design.
[0036] The resistors mentioned here are preferably PTC resistors and have overheat protection due to their temperature-dependent resistance values. In the event of a fault, the PTC resistor will heat up, thereby increasing its resistance and electrically disconnecting it. The cause of the fault can be eliminated during a cooling time, which may be in the range of a few minutes. During this cooling time, the charging station can be electrically disconnected, for example, by disconnecting the AC charging connector from the rectifier device and the circuit, or by disconnecting the external connection between the charging station or its energy source and the vehicle.
[0037] Furthermore, the vehicle charging circuit can be configured to perform at least one of the following safety-related functions. Specifically, the vehicle charging circuit includes a monitoring unit configured to perform at least one of the following functions.
[0038] In particular, the first function of the monitoring unit is, for example, to monitor the voltage on at least one intermediate circuit capacitor by means of a correspondingly connected voltage detection device, wherein if a predetermined voltage limit is exceeded by the detected voltage on the intermediate circuit capacitor, a fault signal is issued (particularly by the monitoring unit). Here, the voltage limit can reflect the design of at least one intermediate circuit capacitor, including, where necessary, a safety limit.
[0039] In particular, the second function of the monitoring unit is to monitor the power consumed by the discharge resistor and to determine the temperature rise of the discharge resistor caused by that power, and to issue a fault signal if the temperature rise exceeds a limit. A variation of this function is to determine the temperature rise based on the power and, if necessary, the duration of the corresponding time period. A fault signal can be issued if the temperature rise exceeds a limit, if the temperature derived from the temperature rise exceeds a limit that can be guided by the temperature design of the discharge resistor and, if necessary, take into account the ambient temperature of the discharge resistor, or if the temperature rise exceeds a predetermined limit within a predetermined duration.
[0040] In particular, a third function of the monitoring unit is to determine whether the at least one intermediate circuit capacitor cannot be fully discharged or cannot be fully discharged within a predetermined time period. The vehicle charging circuit and, in particular, the monitoring unit are configured to: if this is the case, recharge the at least one intermediate circuit capacitor.
[0041] In particular, the fourth function of the monitoring unit is to output a fault signal if the time required for complete discharge is longer than a predetermined time period.
[0042] A discharge with a predetermined energy difference, such as a discharge with an amplitude of 80%, 90%, or 95% of the nominal total capacitance of the at least one intermediate circuit capacitor, is called a complete discharge. Alternatively, a discharge up to or below a voltage value below a safety limit, such as 60V, 40V, 20V, or 5V, is also called a complete discharge.
[0043] Of these functions, one, several, or all are implemented in the vehicle charging circuit, particularly essentially in the monitoring unit. The monitoring unit may be integrated with the control device, implemented using the same hardware, or exchange data with the control device (directly or indirectly). It is possible that these functions are generally implemented in the vehicle charging circuit, for example, in the form of a monitoring unit, which has at least one intermediate circuit capacitor and at least one discharge resistor, and the vehicle charging circuit does not necessarily have the features of the embodiments described herein. Attached Figure Description
[0044] exist Figures 1 to 8 The vehicle charging circuit is illustrated as an example and should be used to understand the feasible implementations, variations and implementations described herein. Detailed Implementation
[0045] Figures 1 to 3 An example for the first variant is shown, where Figure 1 A vehicle charging circuit with a single pre-charge / discharge circuit is shown. Figure 2 and 3 An implementation with multiple pre-charge / discharge circuits is shown, wherein in Figure 2 The intermediate circuit capacitors are directly connected and in Figure 3 The intermediate circuit capacitors described herein are connected to each other through a configuration circuit.
[0046] exist Figure 8 , 5 Figures 4 and 5 show other examples that can be assigned to the second variant scheme, in which Figure 8 A vehicle charging circuit with a single pre-charge / discharge circuit is shown, while Figure 5 and 4 An exemplary charging circuit with multiple pre-charge / discharge circuits is shown. Here, in Figure 5 The intermediate circuit capacitors described in the text are directly interconnected, while... Figure 4 The intermediate circuit capacitors described herein are connected by means of a configuration circuit.
[0047] Figure 6 and 7 This is used to explain the implementation methods that can be assigned to the third variant. Figure 6 and 7 The diagram shows a vehicle charging circuit with multiple intermediate circuit capacitors. Figure 6 These intermediate circuit capacitors are connected to each other through configuration circuitry, and Figure 7 The intermediate circuit capacitors described herein are directly connected to each other.
[0048] Components indicated by the same reference numerals are comparable and, in particular, made of the same type. Current flow is indicated by arrows r and g, where g indicates pre-charge current flow and r indicates discharge current flow. These arrows are used to explain the pre-charge / discharge function.
[0049] Some figures show a DC voltage converter W connected after an intermediate circuit capacitor. This DC voltage converter is optional and can also be present in embodiments where the converter is not explicitly shown in the figures. Instead of the DC voltage converter W, battery terminals or vehicle electrical branch terminals can also be provided for connection to the battery or (if necessary) a vehicle electrical branch.
[0050] Figure 1A vehicle charging circuit with a rectifier device is shown, which is configured as a power factor correction filter (PFC). The PFC is single-phase (“1ph”) and has a first phase input L1 and a neutral conductor input N. When using two phases to power the PFC, a second phase signal L2 can also be applied to the lower input. The input L1 or L2 / N is therefore an AC voltage input. On the opposite side of the rectifier device, there is a DC voltage side with a first potential + and a second potential -. An intermediate circuit capacitor C is connected via a pre-charge / discharge circuit (to be explained in further detail), which in turn connects to a current-separated DC-DC voltage converter W. The DC-DC voltage converter W has two DC voltage terminals HV+ and HV- on the side opposite to the intermediate circuit capacitor C.
[0051] exist Figure 1 A (first) changeover switch S2 is present, which selectively connects the first terminal (+) of the intermediate circuit capacitor C to the discharge resistor PTC2 or to a parallel circuit consisting of switch S1 and pre-charge resistor PTC1. In the unoperated state, the first changeover switch S2 is in position NC and connects the first terminal (+) of the intermediate circuit capacitor C to the discharge resistor PTC2. For direct charging, the changeover switch S2 is in the first circuit LO and connects the first terminal (+) of the intermediate circuit capacitor C to the pre-charge resistor PTC1 and the first switch S1. If switch S1 is open, i.e., in position NC, pre-charging can be performed. If switch S1 is closed, i.e., in position NO, the pre-charge resistor PTC1 is bridged and the rectifier device PFC or its first potential (+) is directly connected to the intermediate circuit capacitor C via switch S1 and changeover switch S2. During discharge, the changeover switch S2 is in a second position, in which the first potential (+) of the rectifier device PFC is separated from the first terminal (+) of the intermediate circuit capacitor C by the changeover switch S2. Therefore, the continuous current flow from the rectifier device PFC through the discharge resistor PTC2 is eliminated in the event of erroneous operation.
[0052] Figure 1 It is a single-phase vehicle charging circuit, wherein a voltage of 400 volts typically appears on the intermediate circuit capacitor C. Other embodiments ( Figures 2 to 7 The diagram shows a three-phase structure in which higher voltages exist on the + and - potentials of the rectifier unit PFC.
[0053] Figure 2A multiphase vehicle charging circuit (three-phase) with a three-phase rectifier device is shown, the rectifier device having three phase terminals L1 to L3 and a neutral conductor terminal N. The neutral conductor terminal is optional and therefore has a star configuration and is connected to the discharge circuit via a dashed line for this reason.
[0054] Figure 2 The circuit has two discharge circuits, which are symmetrically constructed with the connection points between these discharge circuits and two intermediate circuit capacitors C1 and C2. Therefore, a pre-charge / discharge circuit is provided in each potential bus (+, -, connected to the relevant potential), through which the rectifier device PFC is connected to the intermediate circuit capacitors C1 and C2. The two pre-charge / discharge circuits are respectively as shown in... Figure 1 The circuit is constructed as shown in the pre-charge / discharge circuit diagram. The intermediate circuit capacitors C1 and C2 are interconnected via connection points. Figure 1 The discharge resistor PTC2, which is located between the first changeover switch S2 and the second potential, is relative to ground. Figure 2 The discharge resistor PTC2 is connected between the connection point of the corresponding first changeover switch S2 and the intermediate circuit capacitors C1 and C2. The potential of the intermediate point thus replaces that of the circuit. Figure 1 The potential to which the discharge resistor described herein is directly connected.
[0055] In addition, Figure 2 The connection point described herein is connected to the neutral conductor terminal N. Due to its multiphase nature, the rectifier unit PFC (three-phase, 3ph) generates a higher output voltage at both + and - potentials, thereby allowing a voltage drop of 400 volts at each of the series-connected intermediate circuit capacitors C1 and C2.
[0056] If switch S1 is open and changeover switch S2 is in position NO, a pre-charge current is directed through resistor PTC1. For subsequent charging, switch S1 is closed (position NC) and changeover switch S2 is in position NO. This creates a direct connection between the rectifier unit PFC and the intermediate circuit capacitors C1 and C2.
[0057] Connections of resistive components that do not significantly reduce current flow are referred to as direct connections. Shunt resistors (with values of approximately <1 ohm or <10 milliohms) do not fall under this category.
[0058] Figure 3 It shows the relationship with Figure 2 A circuit similar to that of [the circuit mentioned above]. Figure 2Unlike other intermediate circuit capacitors, C1 and C2 are not connected directly but through a configuration circuit. In the example shown, the configuration circuit has a series connection of two diodes D, the junction of which is connected to the neutral conductor N. This allows the asymmetrical three-phase current components to be directed to the neutral conductor. The configuration circuit also has two switches S3. For each switch S3, it is suitable that the switch is connected to one of the intermediate circuit capacitors C1 and C2, not directly connected to one of the changeover switches S2. Each of the changeover switches S3 can selectively connect this terminal to the opposite potential + or - of the rectifier device (in the parallel circuit of the intermediate circuit capacitors) or can connect the two mentioned terminals of the intermediate circuit capacitors C1 and C2 to each other, bypassing the diode N, as shown. However, other configuration circuits are generally conceivable, such as a configuration circuit with two first switches and one third switch, wherein the first switch connects the two intermediate circuit capacitors in parallel to potentials + or -, and the third switch, when closed, connects the two intermediate circuit capacitors in series. Instead of the aforementioned switch, a diode can also be used. The illustrated embodiment specifies that the configuration circuit connects the intermediate circuit capacitor to the + and - potentials of the rectifier device PFC (and not to the potentials of the intermediate circuit capacitor to which the corresponding intermediate terminal of the first changeover switch S2 is connected).
[0059] Figure 4 and 5 Another (second) variant of the pre-charge / discharge circuit is shown, wherein a first changeover switch connects a first potential (and a second potential if necessary) to an intermediate circuit capacitor or a plurality of intermediate circuit capacitors belonging to an intermediate circuit capacitor. The belonging intermediate circuit capacitor can be selectively connected via the first changeover switch (here: S1) to its belonging first potential + (or also to the second potential -) according to a first position NO and to a second changeover switch S2 in a second position NC. The second changeover switch S2 of each pre-charge / discharge circuit selectively connects the first changeover switch S1 to the potential of the rectifier device via a pre-charge resistor PTC1 according to position NO, to which the first changeover switch S1 is also connected, or in position NC to a discharge resistor PTC2 leading to a potential opposite to the potential of the rectifier device and the changeover switch S1 directly connected. This can be achieved by means of… Figure 8 The single-phase structure is clearly visible.
[0060] exist Figure 4 and 5 The text shows the use of [something] in [something]. Figure 8 An exemplary charging circuit illustrating the principle shown. Figure 8This diagram shows a charging circuit with only one pre-charge / discharge circuit and one intermediate circuit capacitor C. Figure 4 and 5 This illustrates a symmetrical power supply, where the vehicle charging circuit shown has two pre-charge / discharge circuits and two intermediate circuit capacitors C1 and C2. Figure 8 The principle shown is that the intermediate circuit capacitor C is connected starting from the rectifier device PFC via the first changeover switch S1. Figure 8 In the diagram, the rectifier device PFC is shown as a single phase (“1ph”) and has a neutral conductor input terminal N and a phase input terminal, which is consistent with... Figure 4 and 5 A rectifier device configured for three-phase operation (“3ph”) is used as a contrast. In the first position NO of the changeover switch S1, the intermediate circuit capacitor C is directly connected to the two potentials + and - of the rectifier device PFC. In the second position NC of the first changeover switch S1, the intermediate circuit capacitor is connected to a second changeover switch S2 via the first changeover switch S1. In the first position NO, the second changeover switch connects the first changeover switch S1 to the first potential of the rectifier device via a pre-charge resistor PTC1, and in the second position NC, it connects the first changeover switch S1 to the second terminal of the intermediate circuit capacitor C via a discharge resistor. Here, via the second changeover switch S2, the first terminal of the capacitor C is connected to the second terminal of the intermediate circuit capacitor in position NC via a discharge resistor PTC2. A discharge current path r is generated. If the first terminal of the intermediate circuit capacitor is connected to the first terminal of the rectifier device via the first changeover switch (position NC) and the second changeover switch (position NO) via the pre-charge resistor PTC1, a pre-charge current path g is generated. If the first changeover switch S1 is in position NO, then the resistor PTC1 and the second changeover switch are also connected across, creating a direct path from the rectifier device PFC to the intermediate circuit capacitor C.
[0061] This is Figure 4 It is used in two pre-charge / discharge circuits. Figure 4 The intermediate circuit capacitors C1 and C2 are connected to each other via a configuration circuit. This configuration circuit has two diodes D and two changeover switches S3, which are configured to selectively connect the intermediate circuit capacitors C1 and C2 in parallel or series. If in Figure 4When the first changeover switch S1 is in position NO, a direct connection is established between the rectifier device PFC and intermediate circuit capacitors C1 and C2 (which are interconnected via configuration circuitry). If the first changeover switch S1 is in position NC, the second changeover switch S2 can select whether the first terminal of the intermediate circuit capacitor (+ for C1 and - for C2 due to symmetry) is connected to the pre-charge resistor PTC1 or the discharge resistor PTC2 via the first changeover switch. As long as the changeover switch S2 is in position NC, the first terminal (see reference numeral + for C1) and the second terminal (see reference numeral + for C2) of the corresponding intermediate circuit capacitors C1 and C2 are connected via resistor PTC2. In position NO of the second changeover switch S2, the first terminals of the intermediate circuit capacitors C1 and C2 are connected to the corresponding potentials + and - of the rectifier device PFC, and the corresponding pre-charge / discharge circuits are connected to the rectifier device.
[0062] The neutral conductor connector N is connected to the junction between the two diodes D and the junction of the changeover switch S2, wherein these junctions are connected to each other. Optionally, the neutral conductor of the rectifier unit PFC can be connected to said junction or to the connector N shown, which is indicated by dashed lines. Figure 4 The figure shows the current path for discharging with reference 'r' and an exemplary pre-charge path via resistor PTC1 with reference 'g'.
[0063] Figure 5 Another example of a vehicle discharge circuit with two pre-charge / discharge circuits is shown, the two pre-charge / discharge circuits respectively according to... Figure 8 The principle of the pre-charge / discharge circuit or according to Figure 4 It works on the principle of [the above]. Two intermediate circuit capacitors, C1 and C2, are also provided here; however, these intermediate circuit capacitors are related to... Figure 4 In contrast, they are directly interconnected. The relevant connection points are connected to the neutral conductor N. Here, the connection point between the intermediate circuit capacitors C1 and C2 can also optionally be connected to the neutral conductor N of the rectifier device (or vehicle charging circuit). In other respects, the discharge circuit corresponds to... Figure 4 The discharge circuit is shown here. The discharge path r and the pre-charge path g are also shown here.
[0064] In, for example, in Figure 4 , 5In the exemplary embodiment shown in Figure 8, it is possible that only the first changeover switch S1 is designed to carry the charging current (i.e., the load current that occurs during charging). Because the changeover switches S2 either only need to conduct the pre-charge current or only need to conduct the discharge current, these changeover switches S2 can be designed with a small current load capacity. Thus, the switch S1 is designed with a higher current load capacity A1 than the current load capacity A2 of the second changeover switch S2. For example, regarding... Figure 4 , 5 In the example of 8, the at least one first transfer switch can be designed with a rated current load capacity A1 or a maximum current load capacity that is twice or at least four, ten, or twenty times greater than the rated current load capacity or maximum current load capacity A2 of the second transfer switch S2.
[0065] Finally, by means of Figure 6 and 7 To explain another exemplary implementation, which follows a third variant. If in Figure 6 and 7 Considering only one of the two pre-charge / discharge circuits, the corresponding intermediate circuit capacitor C1 or C2 is connected to the first potential + or - of the rectifier device via the first changeover switch S1. This relates to the first position NO of the first changeover switch S1. In the second position NC of the changeover switch S1, the first terminal of the intermediate circuit capacitor (which is connected to the rectifier device in the NO position of S1) is connected to a resistor PTC, which in turn leads to the second changeover switch S2. With the aid of the second changeover switch, the resistor PTC can be connected either to the rectifier device PFC or to the intermediate circuit capacitors C1 and C2, depending on whether pre-charging or discharging is desired. Here, the second changeover switch S2 can also be designed with a smaller current load capacity than the first changeover switch S1, because this changeover switch S2 only needs to conduct pre-charge and discharge currents, but not necessarily charging current (i.e., the load current of the charging or feedback process). Furthermore, it should be noted that only one resistor PTC is needed, which is either a pre-charge function resistor or a discharge function resistor depending on the switching position of the changeover switch S2.
[0066] exist Figure 6 The diagram shows two pre-charge / charge circuits among these pre-charge / discharge circuits, each of which is located in a bus + or -, wherein the bus is the connection between the rectifier device and intermediate circuit capacitors C1 and C2. The configuration circuit has been described above, by means of which... Figure 6The intermediate circuit capacitors C1 and C2 described herein can be connected in parallel or in series. In short, like other configuration circuits, Figure 6 The configuration circuit has two diodes D connected in series, with their respective connection points connected to the neutral conductor terminal N. The two changeover switches S3 are configured to selectively connect capacitors C1 and C2 either in parallel or in series. In the series connection, the changeover switch S3 shorts or bridges the diodes. The connection between the shown neutral conductor terminal N and the neutral conductor terminal of the rectifier unit PFC is optional and possible, where this applies to... Figure 6 as well as Figure 7 .
[0067] Figure 7 Comparable vehicle charging circuits are shown, however, in which... Figure 6 Instead of configuring the circuit, the two intermediate circuit capacitors C1 and C2 are directly connected to each other. Furthermore, as in... Figure 6 The same as in Figure 7 The desired discharge path r and the desired precharge path g are also generated.
Claims
1. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit includes a pre-charge resistor and a switch configured as either a normally closed or normally open contact. The switch is connected in parallel with the pre-charge resistor, and the first changeover switch is connected to a first potential of the rectifier device through a parallel circuit consisting of the pre-charge resistor and the switch. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a midpoint connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. The discharge resistors of the two pre-charge / discharge circuits are connected to each other via the midpoint. The two pre-charge resistors of the pre-charge / discharge circuit and a switch connected in parallel with them are connected to different potentials of the rectifier device.
2. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit includes a pre-charge resistor and a switch configured as either a normally closed or normally open contact. The switch is connected in parallel with the pre-charge resistor, and the first changeover switch is connected to a first potential of the rectifier device through a parallel circuit consisting of the pre-charge resistor and the switch. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a configuration circuit configured for selectable parallel or series connection of the intermediate circuit capacitors and connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. The discharge resistors of the two pre-charge / discharge circuits are connected to each other via the configuration circuit, and the two pre-charge resistors of the pre-charge / discharge circuits and a switch connected in parallel with them are connected to different potentials of the rectifier device.
3. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit, in addition to the first switch, also includes a second switch. The first switch is configured to connect, in a second position, the first terminal of the intermediate circuit capacitor to its second terminal via the second switch and the discharge resistor. The second switch is configured to connect, in a first position, the first switch to the first potential of the rectifier device via the pre-charge resistor of the pre-charge / discharge circuit, and in a second position, the first switch to the second terminal of the intermediate circuit capacitor via the discharge resistor. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a midpoint connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. The discharge resistors of the two pre-charge / discharge circuits are connected to each other via the midpoint, and the two pre-charge resistors connect corresponding second switching switches of the pre-charge / discharge circuits to different potentials of the rectifier device.
4. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit, in addition to the first switch, also includes a second switch. The first switch is configured to connect, in a second position, the first terminal of the intermediate circuit capacitor to its second terminal via the second switch and the discharge resistor. The second switch is configured to connect, in a first position, the first switch to the first potential of the rectifier device via the pre-charge resistor of the pre-charge / discharge circuit, and in a second position, the first switch to the second terminal of the intermediate circuit capacitor via the discharge resistor. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a configuration circuit configured for selectable parallel or series connection of the intermediate circuit capacitors. The configuration circuit is connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. The discharge resistors of the two pre-charge / discharge circuits are connected to each other via the configuration circuit, and the two pre-charge resistors connect corresponding second switching switches of the pre-charge / discharge circuits to different potentials of the rectifier device.
5. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit, in addition to the first switch, includes a second switch. The first switch is configured to connect the first terminal of the intermediate circuit capacitor to the second switch via the discharge resistor in the second position, and the second switch is connected to the second terminal of the intermediate circuit capacitor. The second switch is configured to: connect the discharge resistor to a first potential of the rectifier device in the first position, thereby providing the discharge resistor with the additional function of pre-charging; and connect the first switch to the second terminal of the intermediate circuit capacitor via the discharge resistor in the second position to discharge the intermediate circuit capacitor. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a midpoint connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. Second switching devices of the two pre-charge / discharge circuits are connected to each other via the midpoint, and the two first switching devices connect corresponding discharge resistors of the pre-charge / discharge circuits to different potentials of the rectifier device.
6. A vehicle charging circuit comprising a rectifier device, at least one intermediate circuit capacitor, and at least one pre-charge / discharge circuit, wherein the rectifier device is connected to the intermediate circuit capacitor via the pre-charge / discharge circuit, wherein the pre-charge / discharge circuit has at least one first switch configured to: connect a first terminal of the intermediate circuit capacitor to a first potential of the rectifier device in a first position and connect the first terminal of the intermediate circuit capacitor to a second terminal of the intermediate circuit capacitor via a discharge resistor in a second position, wherein the switch is configured to occupy the second switch position in an inactive state. The pre-charge / discharge circuit, in addition to the first switch, includes a second switch. The first switch is configured to connect the first terminal of the intermediate circuit capacitor to the second switch via the discharge resistor in the second position, and the second switch is connected to the second terminal of the intermediate circuit capacitor. The second switch is configured to: connect the discharge resistor to a first potential of the rectifier device in the first position, thereby providing the discharge resistor with the additional function of pre-charging; and connect the first switch to the second terminal of the intermediate circuit capacitor via the discharge resistor in the second position to discharge the intermediate circuit capacitor. in, The vehicle charging circuit also includes a neutral conductor connector, two pre-charge / discharge circuits in the pre-charge / discharge circuit, and two intermediate circuit capacitors in the intermediate circuit capacitors. The intermediate circuit capacitors are connected to each other via a configuration circuit configured for selectable parallel or series connection of the intermediate circuit capacitors. The configuration circuit is connected to the neutral conductor connector. A first pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a first potential of the rectifier device and a first intermediate circuit capacitor in the intermediate circuit capacitors. A second pre-charge / discharge circuit in the pre-charge / discharge circuit is connected between a second potential of the rectifier device and a second intermediate circuit capacitor in the intermediate circuit capacitors. Second switching devices for the two pre-charge / discharge circuits are connected to each other via the configuration circuit. The two first switching devices connect corresponding discharge resistors of the pre-charge / discharge circuits to different potentials of the rectifier device.
7. The vehicle charging circuit according to any one of claims 1 to 6, wherein the first changeover switch is configured as an electromechanical changeover switch having an intermediate connector connected to the intermediate circuit capacitor, and the intermediate connector being selectively connected to a first contact or a second contact of the changeover switch, wherein the discharge resistor is directly or indirectly connected to the second contact, and the first contact is directly or indirectly connected to the rectifier device, and the intermediate connector is connected to the second contact in the non-operated state of the changeover switch.
8. The vehicle charging circuit according to any one of claims 1 to 6, wherein a DC voltage converter of the vehicle charging circuit is connected after the intermediate circuit capacitor.
9. The vehicle charging circuit according to any one of claims 1 to 6, wherein the rectifier device is configured as an active rectifier or as a power factor correction filter.
10. The vehicle charging circuit according to any one of claims 1 to 6, further comprising a monitoring unit, the monitoring unit being configured to: (a) Monitor the voltage on at least one intermediate circuit capacitor and issue a fault signal when the voltage exceeds a predetermined voltage limit; or (b) Monitor the power consumed by the discharge resistor and form the temperature rise caused by the power passing through the discharge resistor from the power, and if the temperature rise exceeds the limit, issue a fault signal, or (c) Determine whether it is impossible to fully discharge the at least one intermediate circuit capacitor or whether it is impossible to fully discharge the at least one intermediate circuit capacitor within a predetermined time period, and if so, recharge the at least one intermediate circuit capacitor; or (d) If the time required for complete discharge is longer than the predetermined time period, a fault signal is output.