Vehicle-mounted charging system and vehicle

Abstract

The invention discloses a vehicle-mounted charging system and a vehicle, and the system comprises an alternating current-direct current conversion circuit which is suitable for charging a battery pack after converting alternating current provided by a power grid into direct current; the switch module is suitable for changing the connection mode of the power grid and the alternating current-direct current conversion circuit, so that the vehicle-mounted charging system works in a single-phase alternating current charging mode or a three-phase alternating current charging mode; and the leakage current suppression circuit is suitable for suppressing the leakage current of the AC-DC conversion circuit. Therefore, while the compatibility of the charging system to single-phase and three-phase input is realized and the capacity requirement of a power device is reduced, a leakage current suppression measure is added to reduce the leakage current generated in the working process of the vehicle-mounted charging system, so that the charging system is adaptive to various types of vehicles and charging environments.

Description

Technical Field

[0001] This invention relates to the field of vehicle charging technology, and more particularly to an on-board charging system and a vehicle. Background Technology

[0002] As the charging power of on-board chargers (OBCs) for new energy vehicles continues to increase, the size, weight, and cost of independent OBC hardware circuits also increase. Currently, integrating OBCs with high-voltage devices in the vehicle can improve circuit integration and power density, reduce circuit costs, and reduce circuit size, which has become the development direction of OBCs. For example, charging functions can be achieved by reusing the windings of the electric drive unit or the motor controller.

[0003] However, the problem with this technology is that, due to the lack of electrical isolation between the grid side and the load side, there will be a significant leakage current during operation. Furthermore, electric vehicle charging typically requires residual current detection, and the charging process is interrupted when the leakage current exceeds the detection threshold, resulting in a poor user experience. Moreover, if the protective earth (PE) wire fails, it could even threaten personal safety. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide an on-board charging system that, while achieving compatibility with single-phase and three-phase inputs and reducing power device capacity requirements, reduces leakage current generated during operation by adding leakage current suppression measures, thereby making the charging system adaptable to various types of vehicles and charging environments.

[0005] The second objective of this invention is to provide a vehicle.

[0006] To achieve the above objectives, the on-board charging system proposed in the first aspect of the present invention includes: an AC-DC conversion circuit adapted to convert AC power supplied by the power grid into DC power to charge a battery pack; a switching module adapted to change the connection mode between the power grid and the AC-DC conversion circuit, so that the on-board charging system can operate in a single-phase AC charging mode or a three-phase AC charging mode; and a leakage current suppression circuit adapted to suppress the leakage current of the AC-DC conversion circuit.

[0007] According to an embodiment of the present invention, the on-board charging system changes the connection mode between the power grid and the AC-DC conversion circuit through a switching module, enabling the on-board charging system to operate in single-phase AC charging mode or three-phase AC charging mode. Furthermore, the AC-DC conversion circuit converts the AC power supplied by the power grid into DC power to charge the battery pack. Additionally, a leakage current suppression circuit suppresses the leakage current of the AC-DC conversion circuit. Thus, while achieving compatibility of the charging system with single-phase and three-phase inputs and reducing the capacity requirements of power devices, the addition of leakage current suppression measures reduces the leakage current generated during the operation of the on-board charging system, thereby making the charging system adaptable to various types of vehicles and charging environments.

[0008] In addition, the on-board charging system according to embodiments of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the switch module includes a first switch, a second switch, a third switch, and a fourth switch, wherein phase A of the power grid is connected to the AC-DC conversion circuit through the first switch, phase B of the power grid is connected to the AC-DC conversion circuit through the second switch, phase C of the power grid is connected to the AC-DC conversion circuit through the third switch, and phase N of the power grid is connected to the AC-DC conversion circuit through the fourth switch.

[0010] According to one embodiment of the present invention, the AC-DC conversion circuit includes at least one electric drive unit, at least one inductor and at least one switching transistor, wherein the at least one electric drive unit is connected to the switching module, the at least one inductor is connected to the leakage current suppression circuit, and the at least one switching transistor is disposed between the at least one inductor and the at least one electric drive unit.

[0011] According to one embodiment of the present invention, the at least one electric drive unit includes a first electric drive unit and a second electric drive unit, wherein the first electric drive unit is disposed between the first switch and the battery pack, and the first electric drive unit includes a first three-phase bridge arm; the second electric drive unit is disposed between the second switch and the battery pack, and the second electric drive unit includes a second three-phase bridge arm.

[0012] According to one embodiment of the present invention, the at least one switching transistor includes a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor, wherein the first switching transistor and the second switching transistor constitute a first bridge arm, and the third switching transistor and the fourth switching transistor constitute a second bridge arm.

[0013] According to one embodiment of the present invention, the at least one inductor includes a first inductor and a second inductor, wherein the intermediate node of the first bridge arm is connected to the leakage current suppression circuit through the first inductor, and the intermediate node of the second bridge arm is connected to the leakage current suppression circuit through the second inductor.

[0014] According to one embodiment of the present invention, when the first switch and the fourth switch are configured to be in a conducting state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the fourth switch, the on-board charging system is configured to operate in a single-phase AC charging mode.

[0015] According to one embodiment of the present invention, the system further includes a common-mode inductor disposed between the switching module and the AC-DC conversion circuit.

[0016] According to one embodiment of the present invention, when the first switch, the second switch, and the third switch are configured to be in a conducting state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the second switch, the on-board charging system is configured to operate in a three-phase AC charging mode.

[0017] According to one embodiment of the present invention, the at least one electric drive unit includes a third electric drive unit, wherein the third electric drive unit is disposed between the third switch and the battery pack, and the third electric drive unit includes a third three-phase bridge arm.

[0018] According to one embodiment of the present invention, when the first switch and the fourth switch are configured to be in a conducting state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the fourth switch, the on-board charging system is configured to operate in a single-phase AC charging mode.

[0019] According to one embodiment of the present invention, when the first switch, the second switch, and the third switch are configured to be in a conducting state, and the first electric drive unit is configured to be connected to the first switch, the second electric drive unit is configured to be connected to the second switch, and the third electric drive unit is configured to be connected to the third switch, the on-board charging system is configured to operate in a three-phase AC charging mode.

[0020] According to one embodiment of the present invention, the leakage current suppression circuit is an active power frequency leakage current suppression circuit, which includes: a Y capacitor; a filter adapted to acquire an excitation source and filter the excitation source; a transformer, the primary side of which is connected to the filter unit, one side of the secondary side of which is connected to the Y capacitor, and the other side of the secondary side of which is connected to the at least one electric drive unit; and a controller connected to at least one switching transistor, adapted to acquire leakage current sampling values ​​and adjust the duty cycle of the at least one switching transistor according to the leakage current sampling values.

[0021] According to one embodiment of the present invention, when the on-board charging system operates in single-phase AC charging mode, the first three-phase bridge arm is configured to be connected in parallel as an A-phase half-bridge, and the second three-phase bridge arm is configured to be connected in parallel as an N-phase half-bridge. The A-phase half-bridge and the N-phase half-bridge are configured such that the upper tube of the A-phase half-bridge and the lower tube of the N-phase half-bridge are switched synchronously, and the lower tube of the A-phase half-bridge and the upper tube of the N-phase half-bridge are switched synchronously, so as to suppress the generation of high-frequency leakage current.

[0022] According to one embodiment of the present invention, when the on-board charging system operates in three-phase AC charging mode, the first switch, the second switch, the third switch and the fourth switch are configured to be in an off state.

[0023] To achieve the above objectives, the vehicle proposed in the second aspect of the present invention includes a battery pack and the on-board charging system described in the above-described embodiments of the present invention.

[0024] According to the embodiments of the present invention, by adopting the aforementioned on-board charging system, the vehicle can achieve compatibility of the charging system with single-phase and three-phase inputs and reduce the capacity requirements of power devices. At the same time, by adding leakage current suppression measures, the leakage current generated during the operation of the on-board charging system is reduced, thereby making the charging system adaptable to various types of vehicles and charging environments.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is a block diagram of an on-board charging system according to an embodiment of the present invention;

[0027] Figure 2 This is a block diagram of an on-board charging system according to an embodiment of the present invention;

[0028] Figure 3 This is a block diagram of an on-board charging system according to a specific embodiment of the present invention;

[0029] Figure 4 This is an electrical schematic diagram of an on-board charging system according to a specific embodiment of the present invention;

[0030] Figure 5 This is a block diagram of an on-board charging system according to another specific embodiment of the present invention;

[0031] Figure 6 This is an electrical schematic diagram of an on-board charging system according to another specific embodiment of the present invention;

[0032] Figure 7 This is a block diagram of a vehicle according to an embodiment of the present invention. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] The on-board charging system and vehicle of the present invention are described below with reference to the accompanying drawings.

[0035] Figure 1 This is a block diagram of an on-board charging system according to an embodiment of the present invention.

[0036] Specifically, in some embodiments of the present invention, such as Figure 1 As shown, the on-board charging system 100 includes: an AC-DC conversion circuit 10, a switching module 20, and a leakage current suppression circuit 30.

[0037] The AC-DC conversion circuit 10 is adapted to convert the AC power supplied by the power grid into DC power to charge the battery pack; the switching module 20 is adapted to change the connection mode between the power grid and the AC-DC conversion circuit 10 so that the on-board charging system 100 can operate in single-phase AC charging mode or three-phase AC charging mode; the leakage current suppression circuit 30 is adapted to suppress the leakage current of the AC-DC conversion circuit 10.

[0038] It is understood that, in this embodiment of the present invention, the on-board charging system 100 can change the connection mode between the power grid and the AC-DC conversion circuit 10 through the switching module 20, so as to realize the circuit switching of the on-board charging system 100 under single-phase and three-phase input conditions, so that the on-board charging system 100 can work in single-phase AC charging mode (corresponding to single-phase input conditions) or three-phase AC charging mode (corresponding to three-phase input conditions). At this time, the AC-DC conversion circuit 10 can convert the AC voltage on the power grid side into the DC voltage on the battery pack side, thereby realizing the charging of the battery pack.

[0039] In addition, during the AC charging process of the vehicle, the common-mode components of the power grid and the common-mode voltage components generated during the high-frequency switching of power devices will form leakage current through the Y capacitor of the vehicle. This leakage current returns to the power grid through the PE line, causing electromagnetic interference and other problems. Therefore, in the above embodiment of the present invention, an additional leakage current suppression circuit 30 is added to suppress the leakage current of the AC-DC conversion circuit 10, so as to eliminate the influence of Y capacitor value drift, thereby improving the reliability and compatibility of the on-board charging system 100.

[0040] Furthermore, in some embodiments of the present invention, such as Figure 4 and Figure 6 As shown, the switch module 20 includes a first switch K81, a second switch K82, a third switch K83, and a fourth switch K84. Phase A of the power grid is connected to the AC-DC conversion circuit 10 through the first switch K81, phase B of the power grid is connected to the AC-DC conversion circuit 10 through the second switch K82, phase C of the power grid is connected to the AC-DC conversion circuit 10 through the third switch K83, and phase N of the power grid is connected to the AC-DC conversion circuit 10 through the fourth switch K84.

[0041] It is understood that in this embodiment of the present invention, when the first switch K81 is configured to be in the conducting state, phase A of the power grid is connected to the AC-DC conversion circuit 10, and when the first switch K81 is configured to be in the open state, phase A of the power grid is disconnected from the AC-DC conversion circuit 10.

[0042] When the second switch K82 is configured to be on, phase B of the power grid is connected to the AC-DC conversion circuit 10; and when the second switch K82 is configured to be off, phase B of the power grid is disconnected from the AC-DC conversion circuit 10. When the third switch K83 is configured to be on, phase C of the power grid is connected to the AC-DC conversion circuit 10; and when the third switch K83 is configured to be off, phase C of the power grid is disconnected from the AC-DC conversion circuit 10.

[0043] When the fourth switch K84 is configured to be in the on state, the N phase of the power grid is connected to the AC-DC conversion circuit 10, and when the fourth switch K84 is configured to be in the off state, the N phase of the power grid is disconnected from the AC-DC conversion circuit 10.

[0044] Therefore, in the above embodiments of the present invention, the on-board charging system 100 consists of a charging pile and a vehicle. The connection mode between the A phase, B phase, C phase and N phase of the power grid and the AC-DC conversion circuit 10 can be changed by changing the first switch K81, the second switch K82, the third switch K83 and the fourth switch K84, thereby realizing the circuit switching of the on-board charging system 100 under single-phase and three-phase input conditions.

[0045] Furthermore, in some embodiments of the present invention, such as Figure 2 As shown, the AC-DC conversion circuit 10 includes at least one electric drive unit 101, at least one inductor 102, and at least one switching transistor 103.

[0046] In this configuration, at least one electric drive unit 101 is connected to the switch module 20, at least one inductor 102 is connected to the leakage current suppression circuit 30, and at least one switch transistor 103 is disposed between at least one inductor 102 and at least one electric drive unit 101.

[0047] It is understood that in this embodiment of the present invention, the AC-DC conversion circuit 10 can increase the power device capacity by reusing the three-phase bridge arm of at least one electric drive unit 101 as one phase bridge arm. After converting the AC power supplied by the grid into DC power with the addition of at least one switch 103 and at least one inductor 102, the battery pack is charged. At the same time, at least one switch 103 is connected to the leakage current suppression circuit 30 through at least one inductor 102, so that the leakage current suppression circuit 30 can generate a reverse leakage current with the battery pack as the excitation source input, and inject the reverse leakage current into the circuit to suppress the leakage current in the single-phase AC charging mode. In this way, the DC power supplied by the battery pack is converted by at least one inductor 102 and at least one switch 103, thereby generating the required current in the leakage current suppression circuit 30, and thus suppressing the leakage current of the AC-DC conversion circuit 10.

[0048] Specifically, in some embodiments of the present invention, such as Figure 3 As shown, at least one electric drive unit 101 includes a first electric drive unit 1011 and a second electric drive unit 1012.

[0049] The first electric drive unit 1011 is disposed between the first switch K81 and the battery pack, and the first electric drive unit 1011 includes a first three-phase bridge arm; the second electric drive unit 1012 is disposed between the second switch K82 and the battery pack, and the second electric drive unit 1012 includes a second three-phase bridge arm.

[0050] It is understood that, in this embodiment of the present invention, the first three-phase bridge arm of the first electric drive unit 1011 can be connected to phase A of the power grid via the first switch K81 to serve as phase A bridge arm, and the second three-phase bridge arm of the second electric drive unit 1012 can be connected to phase B of the power grid via the second switch K82 to serve as phase B bridge arm.

[0051] Specifically, in some embodiments of the present invention, such as Figure 4 and Figure 6 As shown, at least one switching transistor 103 includes a first switching transistor S1, a second switching transistor S2, a third switching transistor S3, and a fourth switching transistor S4.

[0052] Among them, the first switch S1 and the second switch S2 constitute the first bridge arm, and the third switch S3 and the fourth switch S4 constitute the second bridge arm.

[0053] It is understood that, in this embodiment of the present invention, the first bridge arm and the second bridge arm can be rectified or inverted by controlling the opening and closing states of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4.

[0054] More specifically, in some embodiments of the present invention, such as Figure 4 and Figure 6 As shown, at least one inductor 102 includes a first inductor L1 and a second inductor L2.

[0055] The middle node of the first bridge arm is connected to the leakage current suppression circuit 30 through the first inductor L1, and the middle node of the second bridge arm is connected to the leakage current suppression circuit 30 through the second inductor L2.

[0056] It is understood that, in this embodiment of the present invention, the first inductor L1 and the second inductor L2 can play the roles of current smoothing, reducing switching noise, improving efficiency, suppressing short-circuit current, improving power factor, filtering, reducing switching losses and improving stability.

[0057] Furthermore, in some embodiments of the present invention, when the first switch K81 and the fourth switch K84 are configured to be in the on state, and the first electric drive unit 1011 is configured to be connected to the first switch K81 and the second electric drive unit 1012 is configured to be connected to the fourth switch K84, the on-board charging system 100 is configured to operate in single-phase AC charging mode.

[0058] Specifically, in this embodiment of the invention, as Figure 4 As shown, when the first switch K81 and the fourth switch K84 are turned on, and the first electric drive unit 1011 is connected to the first switch K81 (at this time, switch K31 is turned on) and the second electric drive unit 1012 is connected to the fourth switch K84 (at this time, switch K32 is turned on), the on-board charging system 100 operates in single-phase AC charging mode. At this time, the AC-DC conversion circuit 40 reuses the winding M1 of the first electric drive unit 1011 and the winding M2 of the second electric drive unit 1012 as the PFC inductors of phase A and phase N, respectively, and reuses the motor controller (i.e., the first three-phase bridge arm) of the first electric drive unit 1011 and the motor controller (i.e., the second three-phase bridge arm) of the second electric drive unit 1012 as phase A half-bridge and phase N half-bridge, respectively. Generally speaking, the motor stator winding parameters need to be equal, that is, the first electric drive unit 1011 and the second electric drive unit 1012 constitute a single-phase AC-DC module to rectify the AC power provided by the grid into DC power for charging the battery pack.

[0059] Furthermore, in some embodiments of the present invention, such as Figure 4 As shown, the on-board charging system 100 also includes a common-mode inductor L3, which is disposed between the switching module 20 and the AC-DC conversion circuit 10.

[0060] It is understood that, in this embodiment of the present invention, the common-mode inductor L3 can be used to suppress high-frequency leakage current.

[0061] Furthermore, in some embodiments of the present invention, when the first switch K81, the second switch K82, and the third switch K83 are configured to be in the on state, and the first electric drive unit 1011 is configured to be connected to the first switch K81 and the second electric drive unit 1012 is configured to be connected to the second switch K82, the on-board charging system 100 is configured to operate in a three-phase AC charging mode.

[0062] Specifically, in this embodiment of the invention, as Figure 4 As shown, when the first switch K81, the second switch K82, and the third switch K83 are turned on, and the first electric drive unit 1011 (i.e., M1 and its motor controller) is connected to the first switch K81 (i.e., switch K31 is turned on), and the second electric drive unit 1012 (i.e., M2 and its motor controller) is connected to the second switch K82 (i.e., switch K32 is turned on), the on-board charging system 100 operates in three-phase AC charging mode. At this time, the AC-DC conversion circuit 10 reuses the winding M1 of the first electric drive unit 1011 and the winding M2 of the second electric drive unit 1012 as the P phases of phases A and B, respectively. The FC inductor reuses the motor controllers of the first electric drive unit 1011 and the second electric drive unit 1012 as the A-phase half-bridge and B-phase half-bridge, respectively, and connects the additional first bridge arm and the second bridge arm in parallel (at this time, switch S41 is turned on) as the C-phase bridge arm to the third switch K83. That is, the first electric drive unit 1011, the second electric drive unit 1012, the first bridge arm, the second bridge arm, the first inductor L1, the second inductor L2 and the common mode inductor L3 constitute a three-phase AC-DC module to rectify the AC power provided by the grid into DC power for charging the battery pack.

[0063] It should be noted that, in the above embodiments of the present invention, the parameters of the first inductor L1 and the second inductor L2 can be selected to match the winding parameters of the first electric drive unit 1011 and the second electric drive unit 1012, that is, the self-inductance values ​​of L1 and L2 are equal, the self-inductance values ​​of the stator windings of M1 and M2 are equal, and the self-inductance of L1 is equal to twice the self-inductance of the stator winding of M1, so as to ensure the symmetry of the high-frequency switching bridge of the three-phase AC-DC module.

[0064] Furthermore, in some embodiments of the present invention, such as Figure 5As shown, at least one electric drive unit 101 includes a third electric drive unit 1013.

[0065] The third electric drive unit 1013 is located between the third switch K83 and the battery pack, and the third electric drive unit 1013 includes a third three-phase bridge arm.

[0066] It is understood that, in this embodiment of the present invention, the third three-phase bridge arm of the third electric drive unit 1013 can be connected to the C phase of the power grid via the third switch K83 to serve as the C phase bridge arm.

[0067] Furthermore, in some embodiments of the present invention, when the first switch K81 and the fourth switch K84 are configured to be in the on state, and the first electric drive unit 1011 is configured to be connected to the first switch K81 and the second electric drive unit 1012 is configured to be connected to the fourth switch K84, the on-board charging system 100 operates in single-phase AC charging mode.

[0068] It should be noted that, in this embodiment of the present invention, as... Figure 6 The principle of the single-phase AC-DC module composed of the first electric drive unit 1011 and the second electric drive unit 1012 shown is similar to that of... Figure 4 The principle of the single-phase AC-DC module composed of the first electric drive unit 1011 and the second electric drive unit 1012 shown is consistent with that of the single-phase AC-DC module shown. To reduce redundancy, it will not be described again here.

[0069] Furthermore, in some embodiments of the present invention, when the first switch K81, the second switch K82, and the third switch K83 are configured to be in the on state, and the first electric drive unit 1011 is configured to be connected to the first switch K81, the second electric drive unit 1012 is configured to be connected to the second switch K82, and the third electric drive unit 1013 is configured to be connected to the third switch K83, the on-board charging system 100 is configured to operate in a three-phase AC charging mode.

[0070] Specifically, in this embodiment of the invention, as Figure 6As shown, when the first switch K81, the second switch K82, and the third switch K83 are turned on, and the first electric drive unit 1011 (i.e., M1 and its motor controller) is connected to the first switch K81 (at this time, switch K31 is turned on), the second electric drive unit 1012 (i.e., M2 and its motor controller) is connected to the second switch K82 (at this time, switch K32 is turned on), and the third electric drive unit 1013 (i.e., M3 and its motor controller) is connected to the third switch K83 (at this time, switch K33 is turned on), the on-board charging system 100 operates in three-phase AC charging mode. At this time, the AC-DC conversion circuit 10 reuses the winding M of the first electric drive unit 1011. 1. The winding M2 of the second electric drive unit 1012 and the winding M3 of the third electric drive unit 1013 serve as PFC inductors for phases A, B, and C, respectively. The motor controllers of the first electric drive unit 1011, the second electric drive unit 1012, and the third electric drive unit 1013 are reused as half-bridges for phases A, B, and C, respectively. Generally, the stator winding parameters of the motor need to be equal. In this case, the first electric drive unit 1011, the second electric drive unit 1012, the third electric drive unit 1013, and the common-mode inductor L3 constitute a three-phase AC-DC module to rectify the AC power provided by the grid into DC power for charging the battery pack.

[0071] Furthermore, in some embodiments of the present invention, such as Figure 4 and Figure 6 As shown, the leakage current suppression circuit 30 is an active power frequency leakage current suppression circuit, which includes a Y capacitor CY1, a filter, a transformer T1, and a controller.

[0072] The filter is adapted to acquire the excitation source and filter the excitation source; the primary side of the transformer T1 is connected to the filter, one side of the secondary side of the transformer is connected to the Y capacitor CY1, and the other side of the secondary side of the transformer T1 is connected to the at least one electric drive unit 101; the controller is connected to at least one switching transistor 103 and is adapted to acquire the leakage current sampling value and adjust the duty cycle of at least one switching transistor 103 according to the leakage current sampling value.

[0073] It is understood that in some embodiments of the present invention, such as Figure 4 and Figure 6 As shown, the active power frequency leakage current suppression circuit can convert the DC power supplied by the battery pack into a high-frequency AC excitation source input through an inverter circuit composed of the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the first inductor L1, and the second inductor L2. Furthermore, the controller can input the leakage current based on the sampled value I on the PE line. leakThe duty cycle of the high-frequency inverter stage is controlled to eliminate the high-frequency component in the high-frequency inverter output voltage and retain the low-frequency component through the filter. The low-frequency component is applied to both sides of the primary side of transformer T1. One side of the secondary side of the transformer is connected to Y capacitor CY1, and the other side is connected to the common point of capacitors C2 and C3 to inject reverse leakage current into the circuit to suppress leakage current in single-phase AC charging mode. Thus, leakage current of AC-DC conversion circuit 10 is suppressed.

[0074] Optionally, in the above embodiments of the present invention, such as Figure 4 and Figure 6 As shown, filters can include low-pass filters and EMI filters.

[0075] Specifically, in some embodiments of the present invention, on the one hand, under single-phase grid input conditions, the on-board charging system 100 suppresses low- and medium-frequency leakage current through leakage current suppression circuit 30, and ensures that when the positive potential of the DC bus has a jumping trend, the negative potential of the DC bus also has a jumping trend in the opposite direction and of the same amplitude by controlling the symmetrical switching of the high-frequency switching tube in the main circuit of the AC-DC module, thereby achieving high-frequency leakage current cancellation. On the other hand, under three-phase grid input conditions, since the sum of the low- and medium-frequency leakage currents generated by the three phases is theoretically zero, the three-phase bridge arm control strategy is optimized. At this time, it is not necessary to suppress the low- and medium-frequency leakage current through leakage current suppression circuit 30, and the high-frequency leakage current generated in the circuit can be effectively suppressed by common-mode inductor L3.

[0076] Furthermore, in some embodiments of the present invention, when the on-board charging system 100 operates in single-phase AC charging mode, the first three-phase bridge arm is configured to be connected in parallel as an A-phase half-bridge, and the second three-phase bridge arm is configured to be connected in parallel as an N-phase half-bridge, wherein the A-phase half-bridge and the N-phase half-bridge are configured such that the upper tube of the A-phase half-bridge and the lower tube of the N-phase half-bridge are switched synchronously, and the lower tube of the A-phase half-bridge and the upper tube of the N-phase half-bridge are switched synchronously. It is understood that in this embodiment of the present invention, when the on-board charging system 100 operates in single-phase AC charging mode, high-frequency leakage current suppression can be achieved through a symmetrical switching strategy. The symmetrical switching is described as follows: by connecting the first three-phase bridge arm in parallel as an A-phase half-bridge and configuring the second three-phase bridge arm in parallel as an N-phase half-bridge, the A-phase half-bridge and the N-phase half-bridge are configured such that the upper tube of the A-phase half-bridge and the lower tube of the N-phase half-bridge are switched synchronously, and the lower tube of the A-phase half-bridge and the upper tube of the N-phase half-bridge are switched synchronously. As a result, the positive terminal of the high-voltage bus of the battery pack has a positive jump trend, and the negative terminal potential has a negative jump trend of the same amplitude. This ensures that the ground potential of the high-voltage bus of the battery pack remains stable, thereby suppressing the generation of high-frequency leakage current.

[0077] Furthermore, in some embodiments of the present invention, when the on-board charging system operates in three-phase AC charging mode, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are configured to be in an off state.

[0078] It is understood that in this embodiment of the present invention, when the on-board charging system 100 operates in three-phase AC charging mode, the power frequency leakage current is theoretically zero. The three-phase bridge arm control strategy can be optimized to stabilize the potential of the high-voltage bus of the battery pack to ground. At this time, there is no need to suppress the power frequency leakage current, and the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 can be controlled to be in the off state. On the other hand, the high-frequency leakage current generated in the circuit can be effectively suppressed by the common-mode inductor L3.

[0079] In summary, the on-board charging system according to embodiments of the present invention changes the connection mode between the power grid and the AC-DC conversion circuit through a switching module, enabling the on-board charging system to operate in single-phase AC charging mode or three-phase AC charging mode. Furthermore, the AC-DC conversion circuit converts the AC power supplied by the power grid into DC power to charge the battery pack. Additionally, a leakage current suppression circuit suppresses the leakage current of the AC-DC conversion circuit. Thus, while achieving compatibility of the charging system with single-phase and three-phase inputs and reducing the capacity requirements of power devices, the addition of leakage current suppression measures reduces the leakage current generated during the operation of the on-board charging system, thereby making the charging system adaptable to various types of vehicles and charging environments.

[0080] Figure 7 This is a block diagram of a vehicle 1000 according to an embodiment of the present invention.

[0081] Specifically, in some embodiments of the present invention, such as Figure 7 As shown, the vehicle 1000 includes a battery pack 200 and the on-board charging system 100 described in the above embodiment of the present invention.

[0082] It should be noted that the specific implementation of the vehicle in this embodiment of the invention can be found in the specific implementation of the on-board charging system 100 in the foregoing embodiment of the invention. To reduce redundancy, it will not be described again here.

[0083] In summary, the vehicle according to the embodiments of the present invention, by adopting the aforementioned on-board charging system, can achieve compatibility of the charging system with single-phase and three-phase inputs and reduce the capacity requirements of power devices, while reducing the leakage current generated during the operation of the on-board charging system by adding leakage current suppression measures, thereby making the charging system adaptable to various types of vehicles and charging environments.

[0084] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0086] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0087] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0088] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An on-board charging system, characterized in that, The system includes: An AC-DC converter circuit is suitable for converting AC power supplied by the power grid into DC power to charge a battery pack. The switching module is adapted to change the connection mode between the power grid and the AC-DC conversion circuit so that the on-board charging system can operate in single-phase AC charging mode or three-phase AC charging mode. A leakage current suppression circuit is provided to suppress the leakage current of the AC-DC conversion circuit.

2. The on-board charging system according to claim 1, characterized in that, The switch module includes a first switch, a second switch, a third switch, and a fourth switch. Phase A of the power grid is connected to the AC-DC conversion circuit through the first switch, phase B of the power grid is connected to the AC-DC conversion circuit through the second switch, phase C of the power grid is connected to the AC-DC conversion circuit through the third switch, and phase N of the power grid is connected to the AC-DC conversion circuit through the fourth switch.

3. The on-board charging system according to claim 2, characterized in that, The AC-DC conversion circuit includes at least one electric drive unit, at least one inductor, and at least one switching transistor. The at least one electric drive unit is connected to the switching module, the at least one inductor is connected to the leakage current suppression circuit, and the at least one switching transistor is disposed between the at least one inductor and the at least one electric drive unit.

4. The on-board charging system according to claim 3, characterized in that, The at least one electric drive unit includes a first electric drive unit and a second electric drive unit, wherein... The first electric drive unit is disposed between the first switch and the battery pack, and the first electric drive unit includes a first three-phase bridge arm; The second electric drive unit is disposed between the second switch and the battery pack, and the second electric drive unit includes a second three-phase bridge arm.

5. The on-board charging system according to claim 4, characterized in that, The at least one switching transistor includes a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor, wherein the first switching transistor and the second switching transistor constitute a first bridge arm, and the third switching transistor and the fourth switching transistor constitute a second bridge arm.

6. The on-board charging system according to claim 5, characterized in that, The at least one inductor includes a first inductor and a second inductor, wherein the middle node of the first bridge arm is connected to the leakage current suppression circuit through the first inductor, and the middle node of the second bridge arm is connected to the leakage current suppression circuit through the second inductor.

7. The on-board charging system according to claim 6, characterized in that, When the first switch and the fourth switch are configured to be in the ON state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the fourth switch, the on-board charging system is configured to operate in single-phase AC charging mode.

8. The on-board charging system according to claim 6, characterized in that, The system further includes a common-mode inductor, which is disposed between the switching module and the AC-DC conversion circuit.

9. The on-board charging system according to claim 8, characterized in that, When the first switch, the second switch, and the third switch are configured to be in the ON state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the second switch, the on-board charging system is configured to operate in a three-phase AC charging mode.

10. The on-board charging system according to claim 6, characterized in that, The at least one electric drive unit includes a third electric drive unit, wherein... The third electric drive unit is disposed between the third switch and the battery pack, and the third electric drive unit includes a third three-phase bridge arm.

11. The on-board charging system according to claim 10, characterized in that, When the first switch and the fourth switch are configured to be in the ON state, and the first electric drive unit is configured to be connected to the first switch and the second electric drive unit is configured to be connected to the fourth switch, the on-board charging system is configured to operate in single-phase AC charging mode.

12. The on-board charging system according to claim 11, characterized in that, When the first switch, the second switch, and the third switch are configured to be in the ON state, and the first electric drive unit is configured to be connected to the first switch, the second electric drive unit is configured to be connected to the second switch, and the third electric drive unit is configured to be connected to the third switch, the on-board charging system is configured to operate in a three-phase AC charging mode.

13. The on-board charging system according to claim 6, characterized in that, The leakage current suppression circuit is an active power frequency leakage current suppression circuit, which includes: Y capacitor; A filter, adapted to acquire an excitation source and filter the excitation source; A transformer, wherein the primary side of the transformer is connected to the filter, one side of the secondary side of the transformer is connected to the Y capacitor, and the other side of the secondary side of the transformer is connected to the at least one electric drive unit; A controller, connected to at least one switching transistor, is adapted to acquire a leakage current sampling value and adjust the duty cycle of the at least one switching transistor according to the leakage current sampling value.

14. The on-board charging system according to any one of claims 7 or 11, characterized in that, When the on-board charging system operates in single-phase AC charging mode, the first three-phase bridge arm is configured to be connected in parallel as an A-phase half-bridge, and the second three-phase bridge arm is configured to be connected in parallel as an N-phase half-bridge. The A-phase half-bridge and the N-phase half-bridge are configured to have their upper tube of the A-phase half-bridge and lower tube of the N-phase half-bridge switched synchronously, and their lower tube of the A-phase half-bridge and upper tube of the N-phase half-bridge switched synchronously.

15. The on-board charging system according to claim 12, characterized in that, When the on-board charging system operates in three-phase AC charging mode, the first switch, the second switch, the third switch, and the fourth switch are configured to be in the off state.

16. A vehicle, characterized in that, The vehicle includes a battery pack and an on-board charging system as claimed in any one of claims 1-15.

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