Electric vehicle charging device and charging system

Abstract

The present invention provides a charging device that reduces the space and cost required to install both an onboard charging (OBC) unit and a wireless power transmission (WPT) unit within an electric vehicle (EV). [Solution] The charging device 400 includes a WPT unit 410 which includes a WPT input 411 which receives power inductively received by a WPT receiving coil 507 and a WPT output 412 which supplies high-frequency AC power; an OBC unit 420 which includes an OBC input 421 which connects to an external power supply system 602, a power conversion circuit 422 which converts the supplied power to high-frequency AC power and an OBC output 423 which supplies high-frequency AC power; a rectifier 430 which converts the supplied high-frequency AC power to DC; an output unit 440 which connects the rectifier to the traction battery 601 of the EV600 to supply DC power; and a switching unit 450 which is positioned between the WPT output and the OBC output and the rectifier and connects the high-frequency AC power to the rectifier.

Description

Technical Field

[0001] The present invention relates to a charging device configured to be installed in an electric vehicle for charging a traction battery of the electric vehicle. The invention further relates to a charging system and an electric vehicle.

[0002] Electric vehicles (EVs) are typically charged via a charging cable plugged into the EV's charging port. An on-board charging (OBC) unit converts power, which may be DC or AC power, into DC power to charge the EV's traction battery (also referred to as a high voltage (HV) battery) and optionally a low voltage (LV) battery. Wireless charging is envisioned through the use of a WPT system having a ground assembly (GA) with a transmit coil installed in or on the ground, and a vehicle assembly (VA) installed in or on the bottom of the EV having a wireless power transfer (WPT) unit and a receive coil, between which power can be inductively transferred. OBC units and WPT units are generally known.

[0003] When both charging units, i.e., the OBC unit and the WPT unit, are separately installed in an EV, it is necessary to ensure sufficient space for the installation of these units, including electrical harnesses and connectors for HV and LV power supplies, communication means, cooling hoses, connectors, and the like.

[0004] It is an object of the present invention to reduce the space and cost for installing both charging units in an EV.

[0005] In a first aspect of the present invention, there is provided a charging device configured to be installed in an electric vehicle for charging a traction battery of the electric vehicle, the charging device comprising: a wireless power transfer (WPT) unit having a WPT input configured to receive power inductively received by a WPT receive coil from a WPT transmit coil, and a WPT output configured to provide high-frequency AC power; - An on-board charging (OBC) unit having an OBC input configured to connect to a power supply connector for supplying power from a power supply system, a power conversion circuit configured to convert the supplied power into high-frequency AC power, and an OBC output configured to supply high-frequency AC power, - A rectifier configured to convert high-frequency AC power supplied by a WPT unit or OBC unit into DC power, - An output unit configured to supply DC power to the traction battery of an electric vehicle by connecting a rectifier to the traction battery, - A switching unit positioned between the WPT output, OBC output, and rectifier, configured to connect the high-frequency AC power supplied by the WPT unit or OBC unit to the rectifier. It is equipped with.

[0006] A further aspect of the present invention relates to an electric vehicle comprising a traction battery and a charging system disclosed herein for charging the traction battery.

[0007] Preferred embodiments of the present invention are defined in the dependent claims. It should be understood that the claimed electric vehicle has similar and / or identical preferred embodiments to the claimed charging device, as defined in the dependent claims and disclosed herein.

[0008] The present invention is based on the idea that, due to the resonant characteristics of converters commonly used in OBC units and WPT units, and the fact that both charging units do not typically operate in parallel, it is possible to share blocks so that an integrated charging device can be provided in, for example, a single package, thus reducing volume, weight, and cost. By providing a switching unit to switch between the OBC unit and the WPT unit for charging, at least the rectifier of the OBC unit can be shared with the WPT unit.

[0009] In one embodiment, the charging device further comprises a compensation network configured to compensate for reactive power. The compensation network is coupled between the WPT input and WPT output of the WPT unit. The compensation network may be located outside or inside the OBC unit. The latter embodiment has the advantage of further reducing the size and / or cooling requirements of the WPT unit.

[0010] In another embodiment, the OBC unit further comprises a cooling connector configured to connect a heat exchanger. One or more components that were conventionally provided within the WPT unit are now shared with the OBC unit and preferably located within the OBC unit, so a separate cooling connector for the WPT unit may be omitted.

[0011] In another embodiment, the OBC unit further comprises a control unit configured to control the switching unit. The control unit may be further configured to control the rectifier, but alternatively, it may be configured as a separate control unit. Thus, a separate control unit for the WPT unit, as conventionally provided to control the rectifier of the WPT unit, may be omitted.

[0012] Preferably, the control unit is configured to detect whether power is being supplied to the OBC unit or WPT unit and to control the switching unit accordingly. Detection can be performed, for example, by measuring the current or voltage supplied to the OBC input or OBC converter, and by measuring the current or voltage supplied to the receiving coil of the WPT unit or the WPT input of the OBC unit. If power is supplied to the OBC unit, the switching unit is controlled to supply this power to the rectifier. If power is supplied to the WPT unit, the switching unit is controlled to supply this power to the rectifier. Generally, charging via the OBC unit or WPT unit is used simultaneously.

[0013] In another embodiment, the OBC unit is configured for bidirectional power transmission and includes a CLLLC resonant converter (i.e., having an active rectifier), or the OBC unit is configured for unidirectional power transmission and includes an LLC resonant converter (i.e., having a passive rectifier). Thus, the switching unit and rectifier can be controlled accordingly to ensure the desired direction of power flow.

[0014] In another embodiment, the power conversion circuit comprises one or more of an AC / DC converter, a DC / AC converter, a resonant tank, and a high-frequency transformer. These are common components of a charging device and are provided according to the desired application.

[0015] In another embodiment, the charging device may further include a housing that commonly accommodates the WPT unit and the OBC unit. This further saves space because separate housings are not provided for the WPT unit and the OBC unit.

[0016] In another embodiment, the OBC unit further comprises a low-voltage (LV) battery connector configured to connect the OBC unit to the low-voltage battery of an electric vehicle and receive power from the low-voltage battery (i.e., to power the auxiliary circuits of the OBC unit and the WPT unit). The LV battery connector may also be used to communicate with the vehicle, for example, via a CAN bus or any other communication network. This connection can also be shared between the OBC unit and the WPT unit, i.e., a separate LV battery connector for the WPT unit is not required.

[0017] These and other aspects of the present invention will become apparent and clarified with reference to the embodiments described below. [Brief explanation of the drawing]

[0018] [Figure 1]This diagram shows a typical layout of a WPT system for electric vehicles. [Figure 2] A schematic diagram of a commonly known OBC system for EVs is shown. [Figure 3] This diagram shows a schematic of the charging system within an EV, including the separately implemented WPT system and OBC system 200. [Figure 4] A first embodiment of the charging device and charging system according to the present invention is shown. [Figure 5] A second embodiment of the charging device and charging system according to the present invention is shown. [Figure 6] A flowchart illustrating the control method of the switching unit is shown. [Figure 7] The circuit diagram for a capacitor-inductor-inductor-inductor-capacitor (CLLLC) resonant converter for use as a resonant tank is shown.

[0019] Figure 1 shows a schematic diagram of a commonly known WPT system 100 for the EV120, as disclosed, for example, in European Patent Application Publication No. 3694079. In this WPT system 100, the basic functional blocks for inductive charging are shared between a ground assembly (GA) 101 and a vehicle assembly (VA) 102, each of which represents a separate WPT device of the WPT system 100. The WPT system 100 includes an inductive charging coil assembly 112 comprising a transmitter coil (also called a transmitting coil or GA coil) 107 located on the GA side and a receiver coil (also called a receiving coil or VA coil) 108 located on the vehicle side.

[0020] The ground assembly GA 101 of the wireless power transfer WPT system 100 comprises an AC / DC converter 104 with power factor correction PFC that converts single-phase or three-phase power supplied by an (external) AC power source 103 into stabilized DC power. The GA 101 further comprises a DC-to-high-frequency (HF) AC converter 105 that generates a square-wave voltage having a substantially constant frequency and duty cycle. A primary compensation circuit 106, which is a passive circuit network, compensates the inductance of the transmitter coil to reduce the amount of reactive power output by the DC-HF AC converter 105. The transmitter coil 107 transmits power via a magnetic field and provides additional insulation between the AC power inlet and a vehicle high-voltage (HV) battery 111 (also referred to as a traction battery).

[0021] The vehicle assembly VA 102 comprises a receiver coil 108 that captures power via the magnetic field and provides additional insulation between the AC power inlet and the vehicle HV battery 111. A secondary compensation circuit 109, which is a passive circuit network, compensates the receiver coil inductance to maximize transmission power during electrical resonance. The VA 102 comprises an (active or passive) AC / DC rectifier 110 that converts high-frequency AC current into DC current to charge the vehicle HV battery. A DC / DC battery charger (which may or may not include a battery charging algorithm / charging strategy) may optionally be provided. The VA 102 may either comprise the HV battery 111 or be connected to the HV battery 111.

[0022] The architecture of a VA may vary depending on many criteria including network compensation or charging / discharging strategies. Charging of the high-voltage battery 111 may be handled by assemblies in both the GA 101 and the VA 102 of the WPT system 100, and this design allows the optimal WPT architecture to be determined.

[0023] Figure 2 shows a schematic diagram of a generally known on-board charger (OBC) system 200 for an EV. The OBC system 200 comprises an AC / DC converter 202 provided with a PFC that converts single-phase or three-phase power supplied by an (external) AC power source 201 into stabilized DC power. The OBC system 200 further comprises a DC-high frequency (HF) AC converter 203 that generates a square wave voltage having a variable or constant frequency depending on the operating point of the battery and the required power. A resonant tank 204 ensures power transmission at resonance to maximize the efficiency of the power converter. A high-frequency transformer 205 provides insulation between an AC network (components 203, 204) and a vehicle high-voltage (HV) battery 208 corresponding to the vehicle HV battery 111 shown in Figure 1. A rectifier 206 converts the high-frequency AC current into a DC current to charge the vehicle HV battery 208. The rectifier 206 may be an active or passive rectifier, and may use, for example, diodes, IGBTs, MOSFETs, etc. One or more control and protection boards 207 may be provided to control and protect the components of the OBC system 200.

[0024] Figure 3 shows a charging system 300 in an EV 301 configured under the assumption that both charging systems, that is, a wireless power transfer (WPT) vehicle assembly (VA) 302 (which can be implemented and operated like the VA 102 shown in Figure 1) and an OBC system 303 (which can be implemented and operated like the OBC system shown in Figure 2) are separately used and implemented to charge a traction battery 304. In this case, the EV 301 must reserve sufficient space for installation of both charging systems 302 and 303, including one or more of an electric harness (not shown), connectors for HV power supplies 305, 306 and LV power supplies 307, 308, communication connectors 309, 310, cooling hoses and connectors 311, 312, and the like. Furthermore, separate controllers 112, 207 that require arbitration and synchronization from an upper level are provided. All of this increases cost, complexity, space, and other effort.

[0025] Due to the resonant characteristics of the converters in both the OBC system and the WPT charging system, and the fact that the two charging systems do not operate in parallel, it is possible to share blocks so that an integrated charging device, preferably implemented in a single package, is provided by the present invention, thus reducing complexity, volume, weight, and cost, and providing additional wireless charging functionality as an add-on in a simple and cost-effective manner.

[0026] One of the ideas behind this invention is that the power electronics circuits of an OBC system and a WPT VA are quite similar, or even partially identical, and that similar electronic circuits and functions are used to make them work properly. This means that for one or more of these electronic circuits and functions, components common to both the OBC system and the WPT VA can be used, such as one or more of a common microcontroller, a common low-power supply, a common current and voltage sensor, a common overvoltage and overcurrent protection device, a common temperature sensor, etc. Furthermore, since these components do not operate simultaneously in parallel, they can be efficiently used for both the OBC charging system and the WPT VA if they share the same housing / package. For example, the same microcontroller / control unit can control the DC-HF AC unit and the rectifier in OBC mode or the rectifier in WPT charging mode of the OBC system. When two separate devices (OBC system and WPT VA) are used separately, as in the charging system shown in Figure 3, two separate microcontrollers (112, 207 in Figure 3) that do not operate simultaneously are required. For example, the same applies to other components, including busbars or cables, from each rectifier (110, 206 in Figure 3) to the HV battery 304.

[0027] Figure 4 shows one embodiment of a charging device 400 and charging system 500 according to the present invention. The charging device 400 is installed in an EV600 for charging the traction battery 601 of an EV and comprises a WPT unit 410 and an OBC unit 420.

[0028] The WPT unit 410 has a WPT input 411 that receives power inductively received by a WPT receiving coil 501, which is part of the charging system 501 but not part of the charging device 400, from a WPT transmitting coil (not shown, 107 in Figure 1), and a WPT output 412 that supplies high-frequency AC power. Furthermore, in this embodiment, the WPT unit 410 includes a compensation network 413 for compensation of reactive power in particular, which can be implemented and operated as compensation network 109 shown in Figure 1. The WPT unit 410 and the WPT receiving coil 501 represent the WPT VA 502.

[0029] The OBC unit 420 has an OBC input 421 to which an external power connector (not shown) is connected for supplying power from an external power supply system 602 (e.g., an AC power supply 201 shown in Figure 2), a power conversion circuit 422 that converts the supplied power into high-frequency AC power, and an OBC output 423 that supplies high-frequency AC power. The power conversion circuit 422 preferably includes an AC / DC converter 424, a DC-HF AC converter 425, a resonant tank 426, and an HF transformer 427, which can be implemented and operated as components 202 to 205 shown in Figure 2.

[0030] The charging device 400 further comprises a (common) (active or passive) rectifier 430 that converts HF AC power supplied by either the WPT unit 410 or the OBC unit 420 into DC power. A (common) output unit 440 is provided as an HV battery connector for connecting the rectifier 430 to the traction battery 601 of the EV600 and supplying DC power to the traction battery 601 for charging. Between the WPT output 412, the OBC output 423, and the rectifier 430 is a switching unit 450 for connecting the HF AC power supplied by either the WPT unit 410 or the OBC unit 420 to the rectifier 430. The switching unit 450 preferably comprises two switches S1, S2 that can be controlled to connect the HF AC power supplied by either the WPT unit 410 or the OBC unit 420 to the rectifier 430.

[0031] The rectifier 430, output unit 440, and switching unit 450 may be separate components, but one or more of them may be part of the OBC system 503.

[0032] In the exemplary embodiment shown in Figure 4, further components are shared between the WPT unit 410 and the OBC unit 420, specifically, an LV supply connector 460, a communication connector 461 (which may be implemented as a common connector with the LV supply connector 460), cooling hoses and connectors 462 for heat exchange and cooling, and a control and protection board 463. In this exemplary embodiment, it is assumed that the WPT VA 502 is passively cooled by natural convection and conduction to the vehicle through the chassis, and thus shares the coolant circuit of the receiving coil 501. However, if additional cooling is required, the WPT VA 502 may also include a coolant-based heat exchanger (not shown). A common control unit, such as the control and protection board 463, may be configured to control switches S1, S2 of the switching unit 450 and commonly used switching elements of a rectifier 430, which may be implemented as a full-bridge rectifier.

[0033] In preferred embodiments of the disclosed charging devices and charging systems, one or more of the following components may be shared: namely, housing / package (preferably, the complete charging device 400 is contained in a common housing or package), busbars, and electrical harnesses.

[0034] Figure 5 shows another embodiment of the charging device 400' and charging system 500' according to the present invention. Unlike the charging device 400 shown in Figure 4, the compensation network 413 is part of the OBC system 503, which further reduces the size and cooling requirements of the WPT VA 502. All other components of the charging device 400' and charging system 500' are generally configured in the same manner as described above with reference to the first embodiment shown in Figure 4.

[0035] Figure 6 shows a flowchart of method 700 for controlling the switching unit 450. In the first step 701, the charging mode is checked by detecting, for example, whether power is being supplied to the OBC unit or WPT unit. If the charging mode is conductive charging mode (via the OBC unit), in step 702, the switching elements of the switching unit 450 are controlled so that S1 is open and S2 is closed. If the charging mode is wireless charging mode (via the WPT unit), in step 703, the switching elements of the switching unit 450 are controlled so that S1 is closed and S2 is open. The vehicle control unit may be a master communication unit for the charging process, or it may play a role in sharing the charging mode with a control unit that ultimately controls the switching process and the charging process via the OBC unit or WPT unit. After the charging process, the method returns to the initial state (step 704).

[0036] Figure 7 shows a circuit diagram of a capacitor-inductor-inductor-inductor-capacitor (CLLLC) resonant converter (i.e., a resonant converter with an active rectifier) ​​as an exemplary implementation of the resonant tank of the OBC unit (426 in Figure 4). Such an implementation allows for bidirectional power flow through the OBC unit. Other implementations can be used similarly. In another embodiment, the resonant tank may be implemented as an LLC resonant converter (i.e., with a passive rectifier).

[0037] The charging device and charging system according to the present invention achieve reductions in volume, weight, and cost. Furthermore, they provide a solution that can be easily offered as a cost-effective add-on function to conventional OBC charging devices.

[0038] Although the present invention is illustrated and described in detail in the drawings and the foregoing description, such illustrations and descriptions should be considered illustrative or descriptive and not limiting, and the present invention is not limited to the disclosed embodiments. Other modifications of the disclosed embodiments can be understood and implemented by a person skilled in the art by examining the drawings, disclosure and appended claims when carrying out the claimed invention.

[0039] In the claims, the word "comprising" does not exclude other elements or processes, and the indefinite article "a" or "an" does not exclude plurals. A single element or other unit may perform the functions of several items described in the claims. The mere fact that certain means are described in different dependent claims does not imply that combinations of these means cannot be used advantageously.

[0040] No reference numeral in the claims should be construed as limiting the scope.

Claims

1. A charging device (400, 400') configured to be installed in an electric vehicle (600) for charging the traction battery (601) of the electric vehicle (600), A wireless power transmission (WPT) unit (410) having a WPT input (411) configured to receive power inductively received by a WPT receiving coil (501) from a WPT transmitting coil, and a WPT output (412) configured to supply high-frequency AC power, An on-board charging (OBC) unit (420) having an OBC input (421) configured to connect to a power supply connector for supplying power from a power supply system, a power conversion circuit configured to convert the supplied power into high-frequency AC power, and an OBC output (423) configured to supply the high-frequency AC power, A rectifier (430) configured to convert the high-frequency AC power supplied by the WPT unit or the OBC unit into DC power, The output unit (440) is configured to connect the rectifier to the traction battery of the electric vehicle and supply DC power to the traction battery, A switching unit (450) is positioned between the WPT output, the OBC output, and the rectifier, and is configured to connect the high-frequency AC power supplied by the WPT unit or the OBC unit to the rectifier. A charging device (400, 400') is provided.

2. The system further comprises a compensation network (413) configured to compensate for reactive power and coupled between the WPT input and the WPT output, The charging device according to claim 1.

3. The compensation network (413) is located outside or inside the OBC unit. The charging device according to claim 1.

4. One or more of the switching unit (430), the rectifier (450), and the output unit (450) are part of the OBC unit. A charging device according to any one of claims 1 to 3.

5. The system further includes a cooling connector (462) configured to connect to a heat exchanger. A charging device according to any one of claims 1 to 4.

6. The system further includes a control unit (463) configured to control the switching unit. A charging device according to any one of claims 1 to 5.

7. The control unit (463) is configured to detect whether power is being supplied to the OBC unit or the WPT unit, and to control the switching unit accordingly. A charging device according to any one of claims 1 to 6.

8. The control unit (463) is further configured to control the WPT unit and the OBC unit. A charging device according to any one of claims 1 to 7.

9. The OBC unit (420) is configured for bidirectional power transmission and includes a CLLLC resonant converter, or the OBC unit (420) is configured for unidirectional power transmission and includes an LLC resonant converter. A charging device according to any one of claims 1 to 8.

10. The power conversion circuit (422) comprises one or more of the following: an AC / DC converter (424), a DC / AC converter (425), a resonant tank (426), and a high-frequency transformer (427). A charging device according to any one of claims 1 to 9.

11. The system further comprises a housing that commonly accommodates the WPT unit and the OBC unit. A charging device according to any one of claims 1 to 10.

12. Further comprising a low-voltage input (461) configured to receive low-voltage power, A charging device according to any one of claims 1 to 11.

13. The cooling connector (462) and / or the control unit (463) and / or the low voltage input (461) and / or the communication input (461) are part of the OBC unit. The charging device according to claim 5 or 6.

14. A WPT receiving coil (501) configured to inductively receive electrical energy from a WPT transmitting coil, A charging device (400, 400') according to any one of claims 1 to 13 and A charging system (500, 500') is provided.

15. An electric vehicle (600) comprising a traction battery (601) and a charging system (500, 500') according to claim 10 for charging the traction battery.

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