Method for operating a vehicle charging device and control device for a charging device

Abstract

The invention relates to a method (800) for operating a vehicle charging device, the charging device (500) comprising an input circuit, an intermediate capacitor (CZ), a bidirectional DC voltage converter, a circuit arrangement (402) and a control device (452), the method (800) being arranged to at least partially reduce or release the charge present on the output side of the DC voltage converter (450), the method comprises the following steps: receiving (810) a signal for releasing a charge present on the output side of the DC voltage converter (450); supplying power (820) to the control device (452) via the circuit device (402); in the discharge mode, the DC-DC converter (450) is actuated (830) by means of the control device (452) in such a way that a charge present on the output side of the DC-DC converter (450) is transferred in the direction of the intermediate interface (300) and charges the intermediate capacitor (CZ).

Description

Technical Field

[0001] The present invention relates to a method for operating a vehicle charging device and a control device for a charging device. Furthermore, the present invention relates to a charging device having a control device, a drive system having a control device or a charging device, a vehicle having a drive system, a computer program, and a computer-readable storage medium. Background Art

[0002] A method for operating a charging device, for example a charging device in a vehicle with an electric drive (such as an electric vehicle or hybrid vehicle), for charging a battery (preferably a storage battery or a traction battery) from an electrical energy source (preferably an external AC power source or a public AC power grid). The charging device converts the sinusoidal AC power of the external energy source into DC power.

[0003] The charging device preferably has a two-stage power electronics system. The first stage, the so-called power factor correction stage (PFC stage), converts the sinusoidal input voltage from the AC voltage network into a DC voltage. The second stage consists of a DC voltage converter or DC / DC converter, which ensures electrical isolation and adapts the voltage level by means of a transformer. Preferably, the output voltage and / or output current are set with the help of circuits and regulation devices to charge the battery. An intermediate capacitor is arranged between the two stages, which buffers power pulsations at a frequency twice that of the energy source AC. These topologies make it possible to maintain an almost sinusoidal input current on the grid side to meet grid-side standards, achieve electrical isolation between the grid and the vehicle to meet safety requirements, and provide a constant output DC current on the battery side to minimize the load on the battery during charging operation.

[0004] In vehicles with electric drives, the battery is also connected to an inverter to supply energy to the electric drive. Typically, a DC voltage converter is connected in parallel with the inverter to supply energy to the vehicle's low-voltage network or onboard electrical system, thereby supplying energy to the control devices. In particular, to prevent electromagnetic interference, consumers in the high-voltage network, such as inverters, DC / DC converters, or DC voltage converters, include capacitors between the high-voltage connections. These capacitors filter out rapid changes in the high-voltage voltage that occur during operation.

[0005] In the event of an accident or before repairs are performed on a vehicle, the charge in capacitors of the vehicle's high-voltage or high-voltage network (Hochvolt-oder Hochspannungsnetz) must be reliably discharged to reliably eliminate the risk of personnel coming into contact with conductors or components of the high-voltage network. As disclosed in EP2516197B1, corresponding discharge circuits are typically provided in separate components of the high-voltage network, such as inverters. To this end, the discharge circuits include additional components, which disadvantageously increase the required installation space and weight. Therefore, there is a need to be able to at least partially centralize these discharge circuits, partially or completely replace them, or accelerate the discharge of the high-voltage network. Summary of the Invention

[0006] The present invention provides a method for operating a charging device for a vehicle. The charging device includes, on the input side, an input interface unit for connecting a single-phase or multi-phase AC voltage having n phases, where n ≥ 1, and an input circuit connected to the input interface unit for providing a DC voltage at at least a bipolar intermediate terminal. The input circuit includes a rectifier circuit for converting the AC voltage on the input side into a DC voltage on the output side. Preferably, the input circuit also includes a PFC stage. Preferred topologies for the input circuit are 3LTNPC, Vienna rectifier, or a (totem pole) PFC circuit. At least one intermediate capacitor is connected between the positive intermediate terminal and the negative intermediate terminal. A bidirectional DC voltage converter is connected to the intermediate terminal on the input side. During charging operation, the bidirectional DC voltage converter is configured to convert the DC voltage present at the intermediate terminal into a charging voltage and provide this charging voltage to a connectable high-voltage network, preferably a connectable battery, on the output side of the DC voltage converter. The high-voltage network, or an electrical load connected to the high-voltage network, includes at least one high-voltage capacitor connected between the potentials of the connectable high-voltage network. A circuit arrangement is connected or coupled to the output side of the DC voltage converter, which generates an internal supply voltage for powering a control unit of the charging device. Preferably, the circuit arrangement is configured to supply power to the control unit from a connectable high-voltage network. Preferably, the circuit arrangement is configured to supply power to the control unit from the connectable high-voltage network during discharge operation. Preferably, the internal supply voltage is the operating voltage of the control unit. The internal supply voltage preferably corresponds to the vehicle's onboard electrical system voltage, for example, 5 volts, 12 volts, 24 volts, or 48 volts. Preferably, the internal supply voltage provides redundancy for an external supply voltage used to power control units in the vehicle. The control unit is configured to control the bidirectional DC voltage converter. This control preferably includes regulating the bidirectional DC voltage converter, controlling power switches of the DC voltage converter, and / or diagnosing the DC voltage converter and executing a diagnostic method. The method is configured to at least partially reduce the charge present at the output side of the DC voltage converter during discharge operation, or preferably discharge capacitance present in the connectable high-voltage network. The charge present is preferably stored in at least one capacitance of a connectable high-voltage network, a high-voltage capacitor, or at least one capacitance of a component of a connectable high-voltage network. The method comprises the step of receiving a signal for discharging the charge present at the output of the DC voltage converter or a fault signal. This signal is preferably determined internally in the charging device or by a control device external to the vehicle and received by the charging device, preferably by a control unit.Preferably, a signal is determined, generated, and sent based on a malfunction, short circuit, insulation fault, diagnosis, maintenance, vehicle stop or parking, or detection that a plug (preferably a signal plug) is not inserted into the charging device. A further step is: powering the control device via or with the aid of a circuit arrangement. In the discharge operation, the DC voltage converter is controlled by means of the control device so that the charge present on the output side is transferred in the direction of the intermediate interface and the intermediate capacitor is charged. Accordingly, in order to discharge the capacitor in the high-voltage network, the energy in the high-voltage network is used to generate an internal supply voltage for the control device with the aid of the circuit arrangement.

[0007] Advantageously, a method is provided that allows for the reliable discharge of capacitances or capacitors of a high-voltage network connected to a charging device. To this end, during a discharge operation, the charge present on the output side is transferred to the input side by means of reverse operation of the bidirectional DC voltage converter of the charging device, thereby charging an intermediate capacitor.

[0008] The external energy source is preferably a single-phase or multi-phase, preferably three-phase, AC voltage network, preferably a public low-voltage network, preferably used to supply electricity to households, industry, and / or infrastructure. Preferably, in North America or Japan, this is a single-phase AC voltage network of 120 or 240 volts. Preferably, in China or Europe, this is a three-phase AC voltage network of approximately 230 volts. For charging operation, the charging device is preferably connected to the corresponding AC voltage network or to the corresponding AC voltage via an n-phase input interface unit. Preferably, the n-phase input interface unit includes a neutral conductor connection for connecting to the neutral conductor of the AC voltage network to be connected. The battery to be charged is preferably a storage battery or a traction battery, the energy of which is used to power the vehicle's electric drive system. The rectifier circuit is preferably a rectifier for converting AC current into DC current. The high-side or low-side switches of the half-bridge are preferably power semiconductor switches, preferably including intrinsic or extrinsic diodes, preferably IGBTs or MOSFETs, preferably based on Si, SiC, or GaN technology. The expression "connecting a center tap to a connecting line, for example" preferably means connecting, contacting or connecting a component by means of a conductive line or an electrical connection. The expression "blocking, preventing, decoupling or blocking a current flow" preferably means disconnecting a conductive line or disconnecting a connection. Preferably, the expression "connecting" is used synonymously with "electrically connecting," wherein "switchable connection" means that the electrical connection can be established or disconnected, preferably by means of a switch or a switching element. Preferably, the expression "arrangement" is used to define the position of an electrical component (preferably a switch or a switching element) within a circuit topology, wherein this includes electrical connections to adjacently arranged electrical components.

[0009] In one design, the method includes the following additional steps:

[0010] A first measured value is determined. The DC voltage converter is controlled by means of a control device during discharge operation so that charge present at the output side of the DC voltage converter is transferred toward the intermediate interface and the intermediate capacitor is charged until the determined first measured value meets a predeterminable first termination criterion. Preferably, the first termination criterion is selected such that termination is implemented when charge transfer from the output side to the input side of the DC voltage converter is confirmed. For example, a first measured value can be determined that represents the voltage present at the output side of the DC voltage converter (preferably a reduced voltage). The transfer of charge toward the intermediate capacitor is terminated when the first measured value meets a predeterminable first threshold value (which represents a predeterminable voltage value present at the output side of the DC voltage converter). Alternatively, the current flow or the transferred energy can be used as the termination criterion, thereby determining a measured value that represents the current flow or duration through the DC voltage converter.

[0011] During the discharge operation, the DC converter is controlled by a control device so that the charge present at the output of the DC converter in the high-voltage network (preferably from a high-voltage capacitor) is transferred toward the intermediate interface and charges the intermediate capacitor. To this end, the control device receives or detects a signal, preferably a fault signal, and then discharges the charge present at the output of the DC converter during the discharge operation. The charging device preferably includes a first measuring device configured to determine a first measured value. This can be a measuring device for directly determining an electrical parameter (current, voltage) at the output of the DC converter. Alternatively, the electrical parameter to be determined (preferably the voltage present at the output of the DC converter or the transferred energy) can be determined or characterized by one or more measuring devices for determining one or more parameters (current, voltage, duration) at the input and / or output of the DC converter, and by means of an adapted calculation. Similarly, the control device can preferably receive the corresponding first measured value or voltage value from a component of the high-voltage network via a bus system. The discharge operation is carried out by the control device until a first termination criterion is met. The first termination criterion is preferably selected such that contact with live parts does not pose a danger to personnel or the charge in the high-voltage network is reduced. The first termination criterion is preferably selected such that a value derived from the relevant international high-voltage safety standard is ensured during termination.

[0012] Advantageously, a method is provided which combines the discharge of a capacitance or capacitor of a high-voltage network connected to a charging device with a measuring device which enables reliable discharge and qualitative recording of the discharge of the high-voltage network.

[0013] In one embodiment, the method includes the following additional steps: determining a second measured value. The DC voltage converter is controlled by means of a control device so that the charge present in the intermediate capacitor is transferred toward the output side of the DC voltage converter and charges at least one high-voltage capacitor of the connectable high-voltage network. This process continues until the determined second measured value meets a second termination criterion. Preferably, the second termination criterion is selected such that termination is implemented when charge transfer from the intermediate capacitor to the output side of the DC voltage converter is confirmed. For example, a second measured value can be determined that represents the voltage (preferably a reduced voltage) present at the input side of the DC voltage converter, at the intermediate connection, or across the intermediate capacitor. Charge transfer toward the output side of the DC voltage converter is terminated when the second measured value meets a predeterminable second threshold value (which represents a predeterminable voltage value present at the input side of the DC voltage converter). Alternatively, the current flow or the energy transferred can be used as the termination criterion, thereby determining a measured value that represents the current flow or duration through the DC voltage converter.

[0014] During discharge operation, the DC converter is further controlled by the control device so that charge is transferred from the intermediate capacitor to the output side of the DC converter and the capacitor (preferably a high-voltage capacitor) present in the connected high-voltage network is recharged. Transferring charge via the DC converter is associated with losses in the DC converter, thereby reducing the amount of charge to be transferred. The charging device preferably includes a second measuring device configured to determine a second measured value. This can be a measuring device for directly determining an electrical parameter (current, voltage) at the intermediate interface. Alternatively, the electrical parameter to be determined (preferably the voltage present at the input side of the DC converter at the intermediate interface or the transferred energy) can be determined or characterized using one or more measuring devices for determining one or more parameters (current, voltage, duration) on the input and / or output side of the DC converter and using an adapted calculation. Similarly, the control device can receive the corresponding second measured value or voltage value (preferably from a component of the high-voltage network via a bus system). Charge transfer and the associated control by the control device continue until a second termination criterion is met. The second termination criterion is preferably selected such that the total charge in the vehicle decreases with each repeated charge transfer to the output side of the DC converter.

[0015] Advantageously, a method is provided which allows for the improved discharging of capacitances or capacitors in a high-voltage network connected to a charger using losses during operation of a DC voltage converter.

[0016] In another embodiment, the above-described method steps are repeated until a third measured value is determined that meets a third termination criterion. Preferably, the third termination criterion is selected such that termination is implemented if contact with live parts does not pose a risk to personnel. To this end, the third measured value is determined in a similar manner to the first measured value and evaluated according to the third termination criterion.

[0017] The steps of discharging the high-voltage network and transferring the charge back to the high-voltage network are repeated until the total charge in the high-voltage network (preferably the vehicle) is sufficiently discharged due to the losses in the DC voltage converter, so that the voltage on the live parts is low enough not to cause danger to personnel, thereby meeting the third suspension criterion.

[0018] Advantageously, a method is provided with a third termination criterion, which ensures that the connected high-voltage network has been discharged without causing danger to personnel.

[0019] In one embodiment, the method includes the further step of discharging the intermediate capacitor by means of a discharge circuit. Preferably, the intermediate capacitor is discharged by connecting a parasitic resistor or a discharge resistor into the intermediate capacitor.

[0020] Advantageously, a method is provided that enables the centralized discharge of capacitances or capacitors of a high-voltage network connected to a charging device. To this end, charge is first transferred from the high-voltage network to an intermediate capacitor, which is discharged by means of a discharge circuit. Preferably, the discharge of the intermediate capacitor can also be carried out in parallel with the step of discharging the high-voltage network and / or the step of returning charge to the high-voltage network, thereby advantageously accelerating the method. Preferably, the described discharge method can be combined with other discharge methods, preferably with methods for generating current pulses using power semiconductors, or with methods for transferring charge from the high-voltage network to storage devices that can be electrically isolated from the high-voltage network to eliminate the possibility of danger to personnel.

[0021] Furthermore, the present invention relates to a control device for a charging device, which is configured to carry out the described method. Preferably, the control device is a charging control device.

[0022] Advantageously, a control device is provided for carrying out the described method. To this end, a DC voltage converter is actuated in such a way that a capacitance or a capacitor of a high-voltage network connected to the charging device is discharged.

[0023] The present invention also relates to a charging device having the described control device. The charging device comprises, on the input side, an input interface unit for connecting a single-phase or multi-phase AC voltage having n phases, where n ≥ 1, and an input circuit connected to the input interface unit for providing a DC voltage at at least a bipolar intermediate connection. At least one intermediate capacitor is connected between the positive intermediate connection and the negative intermediate connection. A bidirectional DC voltage converter is connected to the intermediate connection on the input side and is configured to convert the DC voltage present at the intermediate connection into a charging voltage during charging operation and to provide this charging voltage at a connectable high-voltage network on the output side of the DC voltage converter, preferably at a connectable battery. The high-voltage network comprises at least one high-voltage capacitor connected between the potentials of the connectable high-voltage network. The charging device comprises a circuit arrangement for generating an internal supply voltage for powering the control device of the charging device.

[0024] Advantageously, a charging device is provided which, by means of a control device and a bidirectional DC voltage converter, is configured to discharge capacitance or capacitors of a high-voltage network connected to the charging device.

[0025] In one embodiment, the circuit arrangement is configured to supply power to the control device from a connectable high-voltage network. For this purpose, the circuit arrangement is preferably connected to the output side of a DC voltage converter to generate an internal supply voltage for the control device of the charging device.

[0026] Advantageously, a circuit topology is provided which enables the control device to be supplied with power from a connectable high-voltage network to be discharged.

[0027] In one embodiment, the circuit arrangement for generating the internal supply voltage for the control device of the charging device is a second DC-DC converter for converting energy from the high-voltage network into the internal supply voltage for the control device.

[0028] Advantageously, a design of a circuit arrangement is provided which enables a control device of a charging device to be supplied with power from a connectable high-voltage network.

[0029] In one embodiment, the intermediate capacitor of the charging device comprises at least one electrolytic capacitor. Electrolytic capacitors are particularly suitable for this application because they are resistant to high voltages and cycles.

[0030] Advantageously, a capacitor type is provided which is particularly preferred for this application.

[0031] In one embodiment, the bidirectional DC voltage converter comprises at least one LLC, CLLC or dual active bridge circuit. Likewise, circuit topologies of bidirectional DC voltage converters with or without galvanic isolation can be used depending on the application framework conditions.

[0032] Advantageously, a circuit of the type suitable for use in a bidirectional direct current voltage converter is provided.

[0033] Furthermore, the present invention relates to a drive system for a vehicle having a control device or a charging apparatus as described above, wherein the drive system comprises, in particular, a traction battery, an inverter and / or an electric machine.

[0034] Advantageously, a drive system for an electric vehicle is provided, which has a control device or a charging device and is configured to discharge capacitance or capacitors of a high-voltage network connected to the charging device by means of the charging device in a discharging mode.

[0035] Furthermore, the present invention relates to a vehicle having a drive system as described above.

[0036] Advantageously, a vehicle with an electrified drive system is provided, which has a simplified discharge method.

[0037] Furthermore, the invention relates to a computer program comprising instructions which, when executed by a control device, cause the control device to carry out the described method.

[0038] Furthermore, the present invention relates to a computer-readable storage medium comprising instructions which, when executed by a control device, cause the control device to carry out the described method.

[0039] It goes without saying that the features, properties and advantages of the method are correspondingly applicable or applicable to the control device, the charging device or the drive system and the vehicle, and vice versa.

[0040] Other features and advantages of the embodiments of the present invention will be apparent from the following description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be explained in more detail below with reference to some drawings, in which:

[0042] Figure 1 A schematic diagram shows an embodiment of a circuit topology for a charging device having a control device,

[0043] Figure 2 shows a schematic vehicle having a drive system with a charging device,

[0044] Figure 3 A schematic flow chart of a method for operating a charging device is shown. DETAILED DESCRIPTION

[0045] Figure 1A charging device 500 is shown, preferably for use in a vehicle. Charging device 500 includes, on the input side, an input interface unit 100 for connecting a three-phase AC voltage (illustrated as an example), and an input circuit 200 for providing a DC voltage at a bipolar intermediate terminal 300. An intermediate capacitor CZ is connected between the positive intermediate terminal 310 and the negative intermediate terminal 320. Furthermore, a bidirectional DC voltage converter 450 is connected to the intermediate terminal 300. During charging operation, the DC voltage present at the intermediate terminal 300, i.e., on the input side of the DC voltage converter 450, is converted into a charging voltage and provided at the output side of the DC voltage converter 450 for supplying a high-voltage network 400 connectable to the output side of the DC voltage converter 450 and / or for charging a battery 470 (preferably a traction battery or a high-voltage battery) connectable to the output side of the DC voltage converter 450. The high-voltage network 400 includes at least one high-voltage capacitor CHV, i.e., a capacitor within the high-voltage network 400. The high-voltage capacitor CHV exemplifies at least one of the capacitances of a component connected to the high-voltage network 400. Preferably, the high-voltage network 400 includes multiple electrical consumers. Therefore, a third DC voltage converter 460 (preferably a step-down converter) is preferably connected in parallel with the battery 470 to convert the charging voltage into a low voltage to charge the low-voltage battery 462 and power the vehicle's onboard electrical system, thereby powering the vehicle's control devices. The low-voltage battery 462 (and preferably other low-voltage electrical consumers 480) are connected to the vehicle's onboard electrical system.

[0046] In the event of an accident or before repairing the vehicle, the capacitors of the high-voltage network (Hochvoltnetz) 400 or the high-voltage network (Hochspannungsnetz) of the vehicle must be reliably discharged, thereby reliably eliminating the danger to people when they come into contact with lines or components of the high-voltage network. According to the invention, for this purpose, the DC voltage converter 450 is operated in a discharge operation with the aid of a control device 452, so that the charge present on the output side, in the high-voltage network 400 (preferably from the high-voltage capacitor CHV) is transmitted in the direction of the intermediate interface 300 and the intermediate capacitor CZ is charged. For this purpose, the control device receives or determines a signal, preferably a fault signal, and the control device 452 then uses the discharge operation to perform the release of the charge present on the output side of the DC voltage converter 450. Preferably, the charging device includes a first measuring device (at Figure 1For the sake of clarity, it is not shown here), which is arranged to determine a first measured value that characterizes the voltage present on the output side of the DC voltage converter 450. This can be a first measuring device for directly determining the voltage on the output side of the DC voltage converter. Alternatively, it is also possible to determine or characterize the voltage present on the output side of the DC voltage converter 450 with the aid of one or more measuring devices for determining one or more electrical parameters (current, voltage) on the input side and / or output side of the DC voltage converter and with the aid of adapted calculations. Likewise, the corresponding first measured value or voltage value can be transmitted to the control device 452, preferably with the aid of a bus system from a component of the high-voltage network or on-board power grid of the vehicle. Preferably, the charging device comprises a second measuring device (at Figure 1(not shown for clarity) is configured to determine a second measured value representative of the voltage present at bipolar intermediate connection 300 . This can be a second measuring device for directly determining the voltage at bipolar intermediate connection 300 . Alternatively, the voltage present at bipolar intermediate connection 300 can be determined or characterized using one or more measuring devices for determining one or more electrical parameters (current, voltage) on the input and / or output side of charging device 500 and by means of an adapted calculation. Similarly, the corresponding second measured value or voltage value can be transmitted to control device 452 , preferably via a bus system from a component of the vehicle high-voltage network or onboard electrical system. Charging device 500 also includes circuit arrangement 402 (preferably a second DC-DC converter) configured to generate a supply voltage for control device 452 of charging device 500 . Circuit arrangement 402 is preferably connected to the output side of DC-DC converter 450 so that it can draw energy from the connectable high-voltage network 400 to be discharged to supply control device 452 . This ensures a reliable power supply for the circuit arrangement as long as the high-voltage network 400 to be discharged is connected to the charging device. Control device 452 is configured to control DC voltage converter 450 so that, in a first step, charge from the connectable high-voltage network 400 is first transferred to intermediate capacitor CZ, and then, in a second step, the charge is transferred back to high-voltage capacitor CHV. During the execution of these two steps, the amount of charge stored in high-voltage network 400 decreases due to the significant losses associated with transferring charge through DC voltage converter 450. Preferably, during at least one of these two steps, DC voltage converter 450 is controlled during the discharge operation so that the losses in DC voltage converter 450 are greater than those during the charging operation. These two steps are repeated sequentially until high-voltage capacitor CHV is sufficiently discharged, such that contact with live parts poses no risk to personnel. The first and second steps are terminated when corresponding predefined termination criteria are met. With each repetition, the first and second termination criteria are adjusted so that the system consisting of the charging device and the high-voltage network is significantly discharged as the first or second step is executed. The third termination criterion of the entire discharge process is preset as follows: no danger will be caused to personnel when contacting live parts (preferably live parts of the high-voltage network).

[0047] The exemplary input circuit 200 of the charging device 500, including an exemplary PFC stage, includes a first half-bridge 210, a second half-bridge 220, and a third half-bridge 230. The first, second, and third half-bridges 210, 220, and 230 each include a series circuit with high-side switches 211, 213, and 215 and low-side switches 212, 214, and 216. Center taps between the high-side and low-side switches of the half-bridges are connectable to the first, second, and third input interfaces L1, L2, and L3 of the input interface unit 100, respectively, via first, second, and third connecting lines 110, 120, and 130, respectively, via first, second, and third connecting lines 110, 120, and 130, respectively, via first, second, and third chokes 202, 204, and 206. Thus, the center tap of the first half-bridge 210 is connectable to the first input interface L1 via the first connecting line 110 via the first choke 202. Therefore, the center tap of the second half-bridge 220 is connectable to the second input interface L2 via the second connecting line 120 through the second choke 204. Therefore, the center tap of the third half-bridge 230 is connectable to the third input interface L3 via the third choke 206 through the third connecting line 130. Half-bridges 210, 220, and 230 are connected in parallel. Their ends are connected to the bipolar intermediate interface 300. The high-side switch is connected to the positive intermediate interface 310, and the low-side switch is connected to the negative intermediate interface 320.

[0048] Figure 2 A schematic vehicle 700 is shown having a drive system 600 with a charging device 500. The input interface unit 100 of the charging device 500 is preferably connectable to an external energy source via an electrical connection via a charging interface 105. The external energy source is preferably connected to the charging interface 105 via a wall box. This connection is preferably used for charging operation. However, a regenerative operation is also possible, in which energy is recirculated from the battery 470 to the external energy source. Vehicle 700 is shown here only as an example with four wheels, but the present invention is equally applicable to any vehicle with any number of wheels on land, water, or in the air. The exemplary drive system 600 includes at least one charging device 500 having a control device 452. The charging device 500 preferably includes a circuit arrangement 402 (not shown in the figure) for generating power for the control device 452. The drive system also preferably includes a battery 470, an inverter 472, and / or an electric motor 474. Any other consumers, preferably including other capacitors between the high-voltage interfaces, are preferably connected to the high-voltage network 400 of the drive system 600. The charging device 500 in the vehicle is shown here merely as an example. The charging device can also be designed as a separate charging device 500, preferably as a charging column or wall box, and arranged outside the vehicle.

[0049] Figure 3A schematic flow chart of method 800 for operating charging device 500 is shown. Method 800 begins with step 805. In step 810, a signal is received for discharging the charge present at the output of DC voltage converter 450. In step 820, control device 452 supplies electrical energy via circuit arrangement 402. To this end, circuit arrangement 402 is actuated accordingly, preferably closing and / or actuating corresponding switching devices within circuit arrangement 402. In step 825, a first measured value is determined, which preferably represents the voltage present at the output of DC voltage converter 450. In step 830, DC voltage converter 450 is operated or actuated in a discharging mode such that the charge present at the output of DC voltage converter 450 is transferred toward intermediate connection 300 and charges intermediate capacitor CZ. The charge present at the output of DC voltage converter 450 is preferably transferred toward intermediate connection 300 until the determined first measured value meets a first termination criterion, preferably a predefinable first threshold value, which represents that the voltage present at the output of DC voltage converter 450 has fallen below a predefinable first voltage value. In step 840, a second measured value is preferably determined, which preferably represents the voltage present at the bipolar intermediate connection 300. In step 850, the DC voltage converter 450 is preferably controlled by means of the control device 452 so that the charge present in the intermediate capacitor CZ is transferred toward the output side of the DC voltage converter 450 and at least one high-voltage capacitor CHV in the connectable high-voltage network 400 is charged, preferably until the determined second measured value meets a second termination criterion, preferably a predefinable second threshold value, which represents that the voltage present at the bipolar intermediate connection 300 is below a predefinable second voltage value. The steps of transferring charge from the high-voltage network 400 to the intermediate capacitor CZ and back from the intermediate capacitor CZ to the high-voltage network 400 are preferably repeated, preferably multiple times, until a third measured value is determined that a third termination criterion, preferably a predefinable third threshold value, which represents that the voltage present at the output side of the DC voltage converter 450 is below a predefinable third voltage value. During this repetitive process, step 830 is preferably performed as the last step. In this step, the DC voltage converter 450 is operated or controlled in a discharge mode so that the charge present at the output of the DC voltage converter 450 is transferred toward the intermediate interface 300 and the intermediate capacitor CZ is charged. These steps are thus repeated until the high-voltage network 400 or the high-voltage capacitor CHV is sufficiently discharged so that contact with live parts does not pose a danger to personnel. In step 860, the intermediate capacitor CZ is preferably discharged using a discharge circuit. This step 860 can also be performed in parallel with the other steps of the method. The method ends at step 865.

Claims

1. A method (800) for operating a charging device (500) for a vehicle, in, The charging device (500) comprises, on the input side: an input interface unit (100) for connecting a single-phase or multi-phase AC voltage having n phases, wherein n≥1; and an input circuit (200) connected to the input interface unit for providing a DC voltage at a bipolar intermediate interface (300); An intermediate capacitor (CZ) is connected between the positive intermediate interface (310) and the negative intermediate interface (320). A bidirectional DC voltage converter (450) is connected to the intermediate interface (300) on the input side, and the DC voltage converter is configured to convert a DC voltage present at the intermediate interface (300) into a charging voltage during charging operation, and to provide the charging voltage at a high-voltage network (400) connectable to the output side of the DC voltage converter (450); The high-voltage network (400) comprises at least one high-voltage capacitor (CHV), which is connected between the potentials of the connectable high-voltage network (400). A circuit device (402) is connected to the output side of the DC voltage converter (450) for generating an internal power supply voltage to supply power to a control device (452) of the charging device (500). The method (800) is configured to at least partially reduce or discharge the charge present on the output side of the DC voltage converter (450) during a discharge operation, The method comprises the following steps: receiving (810) a signal for releasing the charge present at the output side of the DC voltage converter (450), supplying power (820) to the control device (452) via the circuit device (402); In discharge operation, the DC voltage converter (450) is controlled (830) by means of the control device (452) so that the charge present on the output side of the DC voltage converter (450) is transferred toward the intermediate interface (300) and charges the intermediate capacitor (CZ).

2. The method according to claim 1, comprising the further steps of: determining (825) a first measurement value, and In discharge operation, the DC voltage converter (450) is controlled (830) by means of the control device (452) so that the charge present at the output side of the DC voltage converter (450) is transferred toward the intermediate interface (300) and the intermediate capacitor (CZ) is charged until the determined first measured value meets a first termination criterion.

3. The method according to claim 2, comprising the further steps of: determining (840) a second measurement value, and The DC voltage converter (450) is controlled (850) by means of the control device (452) so that the charge present in the intermediate capacitor (CZ) is transferred in the direction of the DC voltage converter (450) and charges at least one high-voltage capacitor (CHV) of the connectable high-voltage network (400) until the determined second measured value meets a second termination criterion.

4. The method according to claim 3, wherein: The steps of claims 2 and 3 are repeatedly performed in sequence until the determined third measurement value meets the third termination criterion.

5. The method according to any one of the preceding claims, comprising the further steps of: The intermediate capacitor (CZ) is discharged (860) by means of a discharge circuit.

6. A control device (452) for a charging device (500), The control device is configured to carry out the method (800) according to the preceding claim.

7. Charging device having a control device (452) according to claim 6, in, The charging device (500) comprises, on the input side: an input interface unit (100) for connecting a single-phase or multi-phase AC voltage having n phases, wherein n≥1; and an input circuit (200) connected to the input interface unit for providing a DC voltage at a bipolar intermediate interface (300); An intermediate capacitor (CZ) is connected between the positive intermediate interface (310) and the negative intermediate interface (320). A bidirectional DC voltage converter (450) is connected to the intermediate interface (300) on the input side and is configured to convert a DC voltage present on the intermediate interface (300) into a charging voltage during charging operation, and to provide the charging voltage at a high-voltage network (400) connectable to the output side of the DC voltage converter (450). The high-voltage network (400) comprises at least one high-voltage capacitor (CHV), which is connected between the potentials of the connectable high-voltage network (400). And wherein the charging device (500) includes a circuit device (402) for generating an internal power supply voltage to power a control device (452) of the charging device (500).

8. The charging device (500) according to claim 7, wherein: The circuit arrangement (402) for generating an internal supply voltage for a control device (452) of the charging device (500) is connected to the output side of a DC voltage converter (450).

9. The charging device (500) according to claim 7 or 8, wherein: The circuit arrangement (402) for generating an internal supply voltage for a control device (452) of the charging device (500) comprises a second DC voltage converter for converting energy from a high-voltage network (400) into an internal supply voltage for the control device (452).

10. The charging device according to any one of claims 7 to 9, in, The intermediate capacitor (CZ) comprises at least one electrolytic capacitor.

11. The charging device according to any one of claims 7 to 10, in, The bidirectional DC voltage converter (450) includes at least one LLC, CLLC or dual active bridge circuit.

12. A drive system (600) for a vehicle (700), comprising a control device (452) according to claim 6 or a charging device (500) according to any one of claims 7 to 11, wherein: The drive system (600) comprises, in particular, a traction battery (470), an inverter (472) and / or an electric motor (474).

13. A vehicle (700) having a drive system (600) according to claim 12.

14. A computer program comprising instructions which, when executed by a control device (452) according to claim 6, causes the control device to perform the method (800) according to any one of claims 1 to 5.

15. A computer-readable storage medium comprising instructions, which, when executed by the control device (452) according to claim 6, cause the control device to perform the method (800) according to any one of claims 1 to 5.

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