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 charging device for a vehicle, said charging device (500) comprising an input circuit, an intermediate capacitor (CZ) and a bidirectional DC-DC converter, said method (800) being arranged to at least partially reduce or release the charge present on the output side of the DC-DC converter (450), comprising the following steps: receiving (810) a signal for releasing a charge present on the output side of the DC voltage converter (450); determining (820) a measured value characterizing the voltage present on the output side of the DC voltage converter (450); in the discharge mode, the DC voltage converter (450) is operated (830) in such a way that the charge present on the output side is transferred in the direction of the intermediate capacitor (CZ) until the determined measured value corresponds to a predefinable threshold value which characterizes a voltage value that is below the predefinable voltage value present on the output side of the DC voltage converter (450).

Description

Field of the Invention

[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 also 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, in a vehicle having an electric drive device (such as an electric vehicle or a hybrid vehicle), for charging a battery (preferably a storage battery or a traction battery) from an electrical energy source (preferably an external alternating current power source or a public alternating current power grid). Here, the charging device converts the sinusoidal alternating current of the external energy source into direct current.

[0003] The charging device preferably has a two-stage power electronics device. The first stage, namely the so-called power factor correction stage (PFC stage), converts the sinusoidal input voltage from the alternating voltage network into a direct current voltage. The second stage consists of a direct current voltage converter or a DC / DC converter, which ensures electrical isolation through a transformer and adapts the voltage level. Preferably, the output voltage and / or the output current are set by means of a circuit and a regulating device to charge the battery. An intermediate capacitor is arranged between the two stages, which buffers the power pulsations at twice the frequency of the energy alternating current. These topologies enable an almost sinusoidal input current to be maintained on the grid side to meet the grid-side standards, electrical isolation to be achieved between the grid and the vehicle to meet the safety requirements, and a constant output direct current to be provided on the battery side to minimize the load on the battery during charging operation.

[0004] In a vehicle having an electric drive device, the battery is also connected to an inverter to supply energy to the electric drive motor. Usually, a direct current voltage converter is connected in parallel with the inverter to supply energy to the low-voltage network or in-vehicle power grid of the vehicle to supply energy to the control device. In particular, in order to avoid electromagnetic interference, a capacitor is included between the high-voltage interfaces of consumers in the high-voltage network, such as an inverter, a DC / DC converter, or a direct current voltage converter, which filters the rapid changes in the high-voltage voltage that occur during operation.

[0005] Before an accident occurs or before the vehicle is repaired, the charge in the capacitors of the high-voltage or high-voltage network (Hochvolt-oder Hochspannungsnetz) of the vehicle must be reliably discharged, so as to reliably eliminate the danger to personnel when contacting the wires or components of the high-voltage network. As is known from the document EP2516197B1, corresponding discharge circuits are usually arranged dispersedly in the various components of the high-voltage network, for example, in the inverter. For this purpose, the discharge circuit includes additional components, which disadvantageously increase the required installation space and weight. Therefore, it is necessary to be able to at least partially centralize such 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 (Eingangsanschlusseinheit) for connecting a single-phase or polyphase alternating 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 interface. Such an input circuit includes a rectifier circuit for converting the alternating voltage on the input side into a DC voltage on the output side. Preferably, the input circuit further includes a PFC stage. A preferred topology of such an input circuit is a 3L TNPC, Vienna rectifier, or (totem pole) PFC circuit. At least one intermediate capacitor is connected between the positive intermediate interface and the negative intermediate interface. A bidirectional DC voltage converter is connected to the intermediate interface on the input side. The bidirectional DC voltage converter is configured to convert the DC voltage present at the intermediate interface into a charging voltage during charging operation and provide the charging voltage at a high-voltage network connectable at the output side of the DC voltage converter, preferably at a connectable battery. The method is configured to at least partially reduce the charge present at the output side of the DC voltage converter, or preferably discharge the capacitance present in the connectable high-voltage network. Preferably, the existing charge is stored in at least one capacitance of the connectable high-voltage network or at least one capacitance of a component of the high-voltage network. The method includes the following steps: receiving a signal for releasing the charge present at the output side of the DC voltage converter. Preferably, the signal is determined inside the charging device, or determined by an external control device of the vehicle and received by the charging device, preferably by a control device. Preferably, the signal is determined, generated, and sent based on a functional failure, short circuit, insulation fault, diagnosis, repair, vehicle stop or parking, or detection that a plug (preferably a signal plug) is not inserted into the charging device. The other steps are: determining a measured value characterizing the voltage present at the output side of the DC voltage converter. Operating the DC voltage converter in a discharging operation in such a way that the charge present at the output side is transmitted in the direction of the intermediate interface and the intermediate capacitor is charged until the determined measured value corresponds to a preset threshold, which characterizes a voltage value lower than the preset voltage value present at the output side of the DC voltage converter.

[0007] Advantageously, a method is provided that enables discharging of the capacitance or capacitors of a high-voltage network connected to the charging device. For this purpose, by means of reverse operation of the bidirectional DC voltage converter of the charging device, the charge present at the output side is transmitted to the input side and thus the intermediate capacitor is charged.

[0008] The external energy source is preferably a single-phase or polyphase, preferably three-phase, alternating voltage network, preferably a public low-voltage network, preferably for powering homes, industries, and / or infrastructure. Preferably, in the North American region or the Japanese region, this is a single-phase alternating voltage network of 120 or 240 volts. Preferably, in the Chinese or European regions, this is a three-phase alternating voltage network of approximately 230 volts. For the charging operation of the charging device, the charging device is preferably connected to or connected to the corresponding alternating voltage network via an n-phase input interface unit. Preferably, the n-phase input interface unit includes a neutral wire interface for connecting the neutral wire of the alternating voltage network to be connected. The battery to be charged is preferably a storage battery or a traction battery, and its energy is used to drive the electric drive system of the vehicle. The rectifier circuit is preferably a rectifier for converting alternating current into direct current. The high-side switch or low-side switch of the half-bridge is preferably a power semiconductor switch, which preferably includes an intrinsic or extrinsic diode, preferably an IGBT or a MOSFET, preferably based on Si, SiC, or GaN technology. The expression "for example, connecting the center tap to the connecting wire" preferably means connecting, contacting, or connecting components by means of a conductive line or an electrical connection. The expression "blocking, preventing, decoupling, or preventing current flow" means disconnecting the conductive line or disconnecting the connection. Preferably, the expression "connected (geschaltet)" is used synonymously with "electrically connected (elektrisch verbunden)", where "switchable connection" means that the electrical connection can preferably be established or disconnected by means of a switch or a switching element. Preferably, the expression "arrangement" is used to define the position of electrical components (preferably switches or switching elements) within a circuit topology, where this includes the electrical connection to adjacent electrical components.

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

[0010] 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 to the intermediate capacitor.

[0011] Advantageously, a method is provided that enables centralized discharge of the capacitance or capacitors of a high-voltage network connected to a charging device. For this purpose, the charge is first transferred from the high-voltage network to the intermediate capacitor, and then the intermediate capacitor is discharged by means of a discharge circuit.

[0012] Furthermore, the invention relates to a control device for a charging device, which is configured to perform the described method. Preferably, the control device is a charging control device.

[0013] Advantageously, a control device for performing the described method is provided. For this purpose, the DC voltage converter is controlled in such a way that the capacitance or capacitors of the high-voltage network connected to the charging device are discharged and the charge is transferred into an intermediate capacitor.

[0014] Furthermore, the invention 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 polyphase AC voltage having n phases, where n ≥ 1; and an input circuit for providing a DC voltage at a bipolar intermediate interface. An intermediate capacitor is connected between the positive intermediate interface and the negative intermediate interface. The bidirectional DC voltage converter is connected on the input side to the intermediate interface and is configured to convert the DC voltage present at the intermediate interface into a charging voltage during charging operation and to provide this charging voltage at a high-voltage network connectable on the output side of the DC voltage converter. Preferably, the DC voltage converter is configured to transfer the charge present on the output side in the direction of the intermediate interface and to charge the connected intermediate capacitor during discharging operation.

[0015] Advantageously, a charging device is provided which, by means of a control device, is configured to discharge the capacitance or capacitors of the high-voltage network connected to the charging device during discharging operation.

[0016] In one design, the intermediate capacitor of the charging device comprises at least one electrolytic capacitor. Electrolytic capacitors are particularly suitable for this application because they are voltage-resistant and cycle-resistant.

[0017] Advantageously, a capacitor type particularly suitable for this application is provided.

[0018] In one design, 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 electrical isolation can be used depending on the framework conditions of the application.

[0019] Advantageously, circuit types suitable for use in bidirectional DC voltage converters are provided. Furthermore, the invention relates to a drive system of a vehicle having the control device or the charging device described above, wherein the drive system in particular comprises a traction battery, an inverter and / or an electric motor.

[0020] Advantageously, an electric vehicle drive system is provided which has a control device or a charging device and is configured to discharge the capacitance or capacitors of the high-voltage network connected to the charging device during discharging operation by means of the charging device.

[0021] Furthermore, the invention relates to a vehicle having the drive system described above.

[0022] Advantageously, a vehicle with an electrified drive system is provided, which has a simplified discharging method.

[0023] 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.

[0024] Furthermore, the 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.

[0025] It goes without saying that the features, characteristics and advantages of the method correspondingly apply or are applicable to the control device, the charging device or the drive system and the vehicle, and vice versa.

[0026] Other features and advantages of embodiments of the invention result from the following description in conjunction with the drawings. Description of the Drawings

[0027] The invention will now be explained in more detail on the basis of some drawings, in which:

[0028] Figure 1 a schematic illustration of an embodiment of the circuit topology of a charging device with a control device is shown,

[0029] Figure 2 a schematic vehicle with a drive system with a charging device is shown,

[0030] Figure 3 a schematic flow chart of a method for operating a charging device is shown. Detailed Description

[0031] Figure 1There is shown a charging device 500, preferably for a vehicle. The charging device 500 includes, on the input side, an input interface unit 100 for connecting to a three-phase alternating voltage shown by way of example and an input circuit 200 for providing a direct current voltage at an intermediate interface 300. An intermediate capacitor CZ is connected between a positive intermediate interface 310 and a negative intermediate interface 320. In addition, a bidirectional direct current voltage converter 450 is connected to the intermediate interface 300. During charging operation, the direct current voltage present at the intermediate interface 300, i.e., on the input side of the direct current voltage converter 450, is converted into a charging voltage, and this charging voltage is provided on the output side of the direct current voltage converter 450 for powering a high-voltage network 400 connectable on the output side of the direct current voltage converter 450 and / or for charging a battery 470 (preferably a traction battery or a high-voltage battery) connectable on the output side of the direct current voltage converter 450. The high-voltage network 400 includes at least one high-voltage capacitor CHV, i.e., the capacitance in the high-voltage network 400. The high-voltage capacitor CHV represents, by way of example, at least one of the capacitances on components connected to the high-voltage network 400.

[0032] In the event of an accident or before vehicle repair, the capacitors of the high-voltage network (Hochvoltnetz) 400 or high-voltage network (Hochspannungsnetz) of the vehicle must be reliably discharged, so as to reliably eliminate the danger to personnel when contacting the lines or components of the high-voltage network. According to the present invention, for this purpose, the control device 452 operates the direct current voltage converter 450 in a discharge operation in such a way that the charge present in the high-voltage network 400, preferably from the high-voltage capacitor CHV, on the output side of the direct current voltage converter 450 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 subsequently the control device 452 performs the release of the charge present on the output side of the direct current voltage converter 450 using the discharge operation. Preferably, the charging device includes a measuring device (at Figure 1(not shown for the sake of clarity), which is set to determine a measured value representing the voltage present on the output side of the DC voltage converter 450. This can be a measuring device for directly determining the voltage on the output side of the DC voltage converter. Alternatively, it is also possible to determine or represent the voltage present on the output side of the DC voltage converter 450 as a measured value by means 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 by means of an adapted calculation. Similarly, the corresponding measured value or voltage value can be transmitted to the control device 452, preferably by means of a bus system from components of the high-voltage network or on-board electrical system of the vehicle. The discharge operation is continuously carried out by means of the control device 452 until the determined measured value corresponds to a presettable threshold value, which represents a voltage value lower than the presettable voltage value present on the output side of the DC voltage converter 450. The presettable voltage value present on the output side of the DC voltage converter 450 is selected such that the risk to personnel is excluded when contacting live components.

[0033] An exemplary input circuit 200 of the charging device 500, 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, 230 each include a series circuit with a high-side switch 211, 213, 215 and a low-side switch 212, 214, 216 respectively. The mid-taps between the high-side switch and the low-side switch of the half-bridges are respectively connectable to the first, second and third input interfaces L1, L2, L3 of the input interface unit 100 via the first, second and third choke coils 202, 204, 206 respectively via the first, second and third connection lines 110, 120, 130. Thus, the mid-tap of the first half-bridge 210 is connectable to the first input interface L1 via the first choke coil 202 via the first connection line 110. Thus, the mid-tap of the second half-bridge 220 is connectable to the second input interface L2 via the second choke coil 204 via the second connection line 120. Thus, the mid-tap of the third half-bridge 230 is connectable to the third input interface L3 via the third choke coil 206 via the third connection line 130. The half-bridges 210, 220, 230 are connected in parallel. Their ends are connected to the bipolar intermediate interface 300. The high-side switches are connected to the positive intermediate interface 310, and the low-side switches are connected to the negative intermediate interface 320.

[0034] Preferably, the high-voltage network 400 includes a plurality of consumers. Thus, another DC voltage converter 460, preferably a buck converter, is preferably connected in parallel with the battery 470 for converting the charging voltage into a low-voltage to charge the low-voltage battery 462 and supply the on-board electrical system of the vehicle to supply power to the control equipment of the vehicle. The low-voltage battery 462 and preferably other low-voltage consumers 480 are connected to the on-board electrical system of the vehicle.

[0035] Figure 2A schematic vehicle 700 having a drive system 600 with a charging device 500 is shown. 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. Preferably, the external energy source is connected to the charging interface 105 via a wall box. This connection is preferably used for charging operation. However, a feedback operation can also be performed, in which energy is fed back from the battery 470 to the external energy source. The vehicle 700 is shown here only as an example with four wheels, wherein the present invention can also be used in any vehicle with any number of wheels on land, on water and in the air. The drive system 600 shown as an example includes at least one charging device 500 with a control device 452. In addition, the drive system preferably includes a battery 470, an inverter 472 and / or an electric motor 474. Preferably, any other consumer (which preferably includes other capacitors between the high-voltage interfaces) is connected to the high-voltage network 400 of the drive system 600. The charging device 500 in the vehicle is shown here only as an example. The charging device can also be designed as a separate charging device 500 , preferably as a charging column or a wall box, and arranged outside the vehicle.

[0036] Figure 3 A schematic flow chart of a method 800 for operating a charging device 500 is shown. The method 800 starts with step 805. In step 810, a signal is received for discharging a charge present at the output side of the DC voltage converter 450. In step 820, a measured value is determined which characterizes the voltage present at the output side of the DC voltage converter 450. In step 830, the DC voltage converter 450 is operated or controlled in a discharging mode in such a way that the charge present at the output side of the DC voltage converter 450 is transferred in the direction of the intermediate interface 300 and the intermediate capacitor CZ is charged until the determined measured value corresponds to a predeterminable threshold value, which characterizes a voltage present at the output side of the DC voltage converter 450 which is below a predeterminable value. Preferably, in step 840, the intermediate capacitor CZ is discharged by means of a discharge circuit. The method ends in step 845.

Claims

1. Method (800) for operating a charging device for a vehicle, Among them, The charging device (500) on the input side comprises: an input interface unit (100) for connecting to a single-phase or polyphase AC voltage with n phases, where n≥1; and an input circuit (200) for providing a DC voltage at a bipolar intermediate interface (300); wherein an intermediate capacitor (CZ) is connected between the positive intermediate interface (310) and the negative intermediate interface (320), wherein a bidirectional DC voltage converter (450) is connected on the input side to the intermediate interface (300), and the DC voltage converter is configured to: convert the DC voltage present at the intermediate interface (300) into a charging voltage during charging operation, and provide the charging voltage at a high-voltage network (400) connectable to the output side of the DC voltage converter (450); wherein the method (800) is configured to at least partially reduce or discharge the charge present at the output side of the DC voltage converter (450), The method comprises the following steps: Receiving (810) a signal for discharging the charge present at the output side of the DC voltage converter (450); Determining (820) a measured value characterizing the voltage present at the output side of the DC voltage converter (450); Operating (830) the DC voltage converter (450) in a discharging operation in such a way that the charge present at the output side is transmitted in the direction of the intermediate interface (300) and charges the intermediate capacitor (CZ) until the determined measured value corresponds to a presettable threshold, which threshold characterizes a voltage value lower than a presettable voltage value present at the output side of the DC voltage converter (450).

2. The method according to claim 1, comprising additional steps: Discharging (840) the intermediate capacitor (CZ) by means of a discharging circuit.

3. Control device (452) for a charging device (500), The control device is configured to execute the method according to the preceding claims.

4. Charging device having a control device (452) according to claim 3, Among them, The charging device (500) on the input side comprises: an input interface unit (100) for connecting to a single-phase or polyphase AC voltage with n phases, where n≥1; and an input circuit (200) for providing a DC voltage at a bipolar intermediate interface (300); wherein an intermediate capacitor (CZ) is connected between the positive intermediate interface (310) and the negative intermediate interface (320), wherein a bidirectional DC voltage converter (450) is connected on the input side to the intermediate interface (300) and is configured to convert the DC voltage present at the intermediate interface (300) into a charging voltage and provide the charging voltage at a high-voltage network (400) connectable to the output side of the DC voltage converter (450).

5. The charging device according to claim 4, Among them, The intermediate capacitor (CZ) comprises at least one electrolytic capacitor.

6. The charging device according to claim 4 or 5, Among them, The bidirectional DC voltage converter (450) includes at least one LLC, CLLC, or dual active bridge circuit.

7. Drive system (600) of a vehicle (700), said drive system having a control device (452) according to claim 3 or a charging device (500) according to any one of claims 4 to 6, wherein, The drive system (600) particularly includes a traction battery (470), an inverter (472), and / or an electric motor (474).

8. A vehicle (700) having the drive system (600) according to claim 7.

9. A computer program comprising instructions that, when executed by the control device (452) according to claim 3, cause the control device to perform the method (800) according to claim 1 or 2.

10. A computer-readable storage medium comprising instructions that, when executed by the control device (452) according to claim 3, cause the control device to perform the method (800) according to claim 1 or 2.

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