Charging circuit, control method of charging circuit and vehicle

Abstract

The embodiment of the invention relates to the technical field of charging, and discloses a charging circuit, a control method of the charging circuit and a vehicle, in the charging circuit, a first motor driving circuit comprises a first three-phase motor winding, a second motor driving circuit comprises a second three-phase motor winding, a first charging port is used for being coupled to a charging pile, and a second charging port is used for being coupled to the charging pile. The first motor driving circuit is coupled to the first charging port and used for boosting voltage input into the first charging port so as to charge the battery pack, the second motor driving circuit is coupled to the battery pack, and the control circuit is coupled to the first motor driving circuit and the second motor driving circuit and used for controlling the first motor driving circuit and the second motor driving circuit. And the control module is configured to control at least one phase of motor winding in the second three-phase motor winding to be connected with the first three-phase motor winding when the first motor driving circuit is used for boosting and charging the battery pack so as to increase the inductance value in a boosting loop formed by the first motor driving circuit. According to the technical scheme, the inductance value of the boost loop can be dynamically matched.

Description

Technical Field

[0001] This invention relates to the field of charging technology, specifically to charging circuits, control methods for charging circuits, and vehicles. Background Technology

[0002] With the development of new energy vehicles, battery pack voltage levels are constantly increasing, but the voltage levels of mainstream charging piles remain relatively fixed. When the battery pack voltage is higher than that of the charging pile, problems arise such as the inability to charge or incomplete charging, impacting user experience.

[0003] In related technologies, using multiple motor windings to achieve boost charging has the problem of poor inductance adaptability of the boost circuit, which leads to insufficient charging power and excessive current ripple. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a charging circuit, a control method for the charging circuit, and a vehicle, which aims to solve the technical problem of poor inductance adaptability of the boost circuit in the prior art.

[0005] In a first aspect, embodiments of this application provide a charging circuit for charging a vehicle's battery pack. The charging circuit includes: a first charging port, a first motor drive circuit, a second motor drive circuit, and a control circuit. The first charging port is coupled to a charging pile. The first motor drive circuit is coupled to the first charging port and is used to boost the voltage input to the first charging port to charge the battery pack. The first motor drive circuit includes a first three-phase motor winding. The second motor drive circuit is coupled to the battery pack and includes a second three-phase motor winding. The control circuit is coupled to the first motor drive circuit and the second motor drive circuit and is configured to: when the first motor drive circuit is used to boost the charging voltage of the battery pack, control at least one phase of the second three-phase motor winding to connect to the first three-phase motor winding to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0006] In this embodiment, the control circuit, through coordinated control of the three-phase motor windings in the first and second motor drive circuits, connects at least one phase of the second three-phase motor winding to the first three-phase motor winding when it is necessary to boost the voltage across the first charging port and boost charge the battery pack. This flexibly increases the equivalent inductance of the boost circuit, significantly improving the charging compatibility and stability between the low-voltage input and the battery pack, and avoiding problems such as excessive current ripple and voltage fluctuations caused by insufficient inductance of a single winding. Furthermore, this application optimizes the boost conversion efficiency by dynamically matching the inductance and reuses existing motor drive circuit resources, eliminating the need for additional independent inductors, simplifying the charging circuit topology and improving space utilization.

[0007] In one possible embodiment, the first motor drive circuit further includes a first three-phase bridge arm, wherein the first end of each phase of the first three-phase motor winding is correspondingly coupled to the midpoint of one phase of the first three-phase bridge arm, and the second end of each phase of the first three-phase motor winding is commonly connected to a first common terminal. The second motor drive circuit further includes a second three-phase bridge arm, wherein the first end of each phase of the second three-phase motor winding is correspondingly coupled to the midpoint of one phase of the second three-phase bridge arm, and the second end of each phase of the second three-phase motor winding is commonly connected to a second common terminal.

[0008] In conjunction with the above embodiments, this application couples the first and second three-phase motor windings to the midpoints of their respective three-phase bridge arms. Furthermore, the second ends of the first, second, and third-phase motor windings are each connected together. This application uses interconnected motor windings for control. The control circuit precisely regulates the on / off state and current direction of each phase winding in the three-phase bridge arms, providing reliable topological support for flexibly adjusting the equivalent inductance of the boost circuit, ensuring charging current stability, and reducing ripple interference.

[0009] In one possible embodiment, the control circuit is specifically configured to: when the first motor drive circuit is used to boost charge the battery pack, control the first end of the first phase motor winding in the second three-phase motor winding to connect with the first end of the first phase motor winding in the first three-phase motor winding, and control the first end of the second phase motor winding in the second three-phase motor winding to connect with the negative terminal of the first charging port, so that the first phase motor winding, the second phase motor winding, and the first phase motor winding in the second three-phase motor winding are connected in series, thereby increasing the inductance in the boost circuit formed by the first motor drive circuit. The first phase motor winding and the second phase motor winding in the second three-phase motor winding are any two phase motor windings in the second three-phase motor winding.

[0010] In this embodiment, during boost charging of the first motor drive circuit, by controlling two phases of the second three-phase motor winding to connect to one phase of the first three-phase motor winding and the negative terminal of the first charging port respectively, a three-winding series structure is formed, which can significantly increase the equivalent inductance of the boost circuit. At this time, the vehicle operates in a boost charging state with optimal inductance allocation, maximizing the utilization of the equivalent inductance of the three-phase windings of the multi-motor module. This topology reduces the use of hardware such as relays in the DC boost charging circuit, improves the utilization rate of winding resistance and inductance in the multi-motor system, and can effectively reduce electromagnetic interference problems, excessive motor temperature rise problems, and circuit hardware safety problems caused by excessive bus current ripple in the boost charging system. At the same time, it improves charging stability and energy conversion efficiency under low voltage input, reuses existing winding resources without the need for additional inductors, simplifies the topology, reduces costs, and enhances the flexibility and reliability of system operating condition adaptation.

[0011] In one possible embodiment, the control circuit is specifically configured to: when the first motor drive circuit is used to boost charge the battery pack, control the first end of one phase of the first three-phase motor winding to connect to the second common terminal, and control the first end of at least one phase of the second three-phase motor winding to conduct to the negative terminal of the first charging port, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0012] In this embodiment, by connecting the first end of one phase of the first three-phase motor winding to the second common terminal, and controlling at least one phase of the second three-phase motor winding to be connected to the negative terminal of the first charging port, the inductance resources of the second three-phase motor winding can be flexibly introduced without complex hardware modifications, quickly increasing the equivalent inductance of the boost circuit. This adapts to low-voltage input scenarios of charging piles, avoids charging instability caused by insufficient inductance of a single winding, and simplifies the circuit structure and reduces costs while ensuring the reliability and adaptability of boost charging.

[0013] In one possible embodiment, the inductance in the boost circuit formed by the first motor drive circuit is negatively correlated with the number of phases of the motor windings in the connected second three-phase motor windings.

[0014] In conjunction with the above embodiments, the inductance is negatively correlated with the number of phases connected to the second winding. This application can precisely match the optimal inductance value by increasing or decreasing the number of phases connected to the second winding, based on the charging pile input voltage, battery pack, and charging power requirements. This avoids both the slow charging dynamic response caused by excessive inductance and the ripple and loss problems caused by insufficient inductance, ensuring that the boost circuit always operates in the high-efficiency range, improving energy conversion efficiency, and enhancing control precision.

[0015] In one possible embodiment, the charging power for boost charging of the battery pack is negatively correlated with the inductance.

[0016] In conjunction with the above embodiments, the negative correlation between charging power and inductance allows for adjustment of the number of motor winding phases connected to the boost circuit based on charging power requirements. This application, through this flexible design, enables the charging process to better align with the battery pack charging characteristics, ensuring both charging efficiency and improved charging safety. Furthermore, the flexible adjustment of inductance further suppresses current ripple and device heating, extends the lifespan of the battery and circuit components, and optimizes the overall charging experience.

[0017] In one possible embodiment, the charging circuit further includes: a second charging port for coupling to a charging pile, and a second motor drive circuit coupled to the second charging port for boosting the voltage input to the second charging port to charge the battery pack.

[0018] In this embodiment, a second charging port is added to the charging circuit, and a second motor drive circuit is linked to achieve boost charging, which significantly improves charging flexibility and redundancy reliability. It supports simultaneous access from two charging piles or selective access from a single charging pile, broadening the range of charging scenarios it can adapt to. Furthermore, in the event of a failure in either the charging port or the motor drive circuit, the charging function can be guaranteed to continue normally through the other path, avoiding charging interruptions. In addition, by reusing the boost resources of the second motor drive circuit, there is no need to add an additional independent boost module, simplifying the topology, reducing costs, and improving integration and charging efficiency.

[0019] In one possible embodiment, the charging circuit further includes a switching circuit coupled between the first three-phase motor winding and the second three-phase motor winding. The control circuit is specifically configured to: when the first motor drive circuit is used to boost the charging of the battery pack, control at least one phase of the second three-phase motor winding to connect with the first three-phase motor winding through the switching circuit, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0020] In conjunction with the above embodiments, by setting a switching circuit between the first and second three-phase motor windings, the on / off connection state between the first and second three-phase motor windings can be flexibly controlled. During boost charging, the switching circuit is closed, enabling interconnection between the first and second three-phase motor windings and increasing the equivalent inductance. During non-boost charging, the switching circuit is open, allowing the motor drive circuit to operate independently and avoiding electrical interference between the motor windings. Furthermore, this embodiment eliminates the need for external inductors; the switching circuit enables the reuse and function switching of the motor drive circuit, simplifying the topology and adapting to various vehicle operating conditions.

[0021] In one possible embodiment, the charging circuit further includes: a step-down circuit coupled between the positive and negative terminals of the first charging port; and a control circuit configured to: control the battery pack to step down the voltage across the step-down circuit via a first motor drive circuit when the voltage input to the charging pile is less than the voltage of the battery pack.

[0022] In this embodiment of the application, when the input voltage of the charging pile is lower than the battery pack voltage, the step-down circuit set in the charging port can accurately reduce the voltage by linking the motor drive circuit with the control circuit. This can ensure the safety of each electronic component in the charging circuit, reduce energy loss, dynamically adapt to multiple working conditions, and prevent reverse voltage from impacting the battery pack, thereby achieving safe, stable and efficient operation of charging the battery pack.

[0023] Secondly, this application provides a control method for a charging circuit, the charging circuit including: a first charging port, a first motor drive circuit, and a second motor drive circuit. The first charging port is coupled to a charging pile, the first motor drive circuit is coupled to the first charging port and is used to boost the voltage input to the first charging port to charge the battery pack, the second motor drive circuit is coupled to the battery pack, the first motor drive circuit includes a first three-phase motor winding, and the second motor drive circuit includes a second three-phase motor winding. The method includes: when the first motor drive circuit is used to boost the charging of the battery pack, controlling at least one phase of the second three-phase motor winding to connect to the first three-phase motor winding to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0024] In this embodiment, during boost charging of the first motor drive circuit, at least one phase of the second three-phase motor winding is connected to the first three-phase motor winding to increase the inductance of the boost circuit. This eliminates the need for an additional independent boost inductor, fully utilizing the resources of the dual-motor drive circuit and effectively solving the problems of large current ripple and unstable boosting caused by insufficient inductance when the charging pile has a low-voltage input. It also improves the adaptability and stability of charging from low voltage to high-voltage battery packs.

[0025] In one possible embodiment, the charging circuit further includes a switching circuit coupled between the first three-phase motor winding and the second three-phase motor winding. The control method of the charging circuit further includes: when the first motor drive circuit is used to boost the charging of the battery pack, controlling at least one phase of the second three-phase motor winding to connect with the first three-phase motor winding through the switching circuit, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0026] In this embodiment, a switching circuit is added to the charging circuit. This switching circuit provides reliable and precise on / off control for the interconnection of the three-phase motor windings, preventing misconnections or electrical interference between the three-phase motor windings and improving control safety and stability. During non-boost operation, the winding connection can be disconnected via the switch, ensuring the motor drive circuit operates independently without affecting the normal driving function of the motor. Furthermore, this application can dynamically adjust the number of connected phases according to the charging conditions, accurately matching the optimal inductance, while simplifying the hardware implementation of the control logic and reducing circuit complexity.

[0027] Thirdly, this application provides a vehicle including the charging circuit as described in the first aspect. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application will be described below.

[0029] Figure 1This is a schematic diagram of the structure of a vehicle disclosed in an embodiment of this application; Figure 2 This is a schematic diagram of a charging circuit disclosed in an embodiment of this application; Figure 3 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application; Figure 4 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application; Figure 5 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application; Figure 6 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a charging system disclosed in an embodiment of this application; Figure 8 This is a schematic diagram of the control flow of a charging system disclosed in an embodiment of this application; Figure 9 This is a schematic diagram of the control flow of another charging system disclosed in an embodiment of this application; Figure 10 This is a schematic diagram of the control flow of another charging system disclosed in an embodiment of this application; Figure 11 This is a schematic diagram of the control flow of another charging system disclosed in an embodiment of this application; Figure 12 This is a schematic diagram of a three-loop control system disclosed in an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures: 1-Vehicle; 2-Charging system; 10-Battery pack; 20-Charging circuit; 30-Battery controller; 40-Vehicle controller; 50-Port voltage sampling module; 60-Bus voltage sampling module; 70-Charging pile; 201-First motor drive circuit; 202-Second motor drive circuit; 203-Control circuit; 204-First charging port; 205-Step-down circuit; 206-Second charging port; 207-Second step-down circuit; 2011 - First three-phase motor winding; 2012 - First three-phase bridge arm; 2021 - Second three-phase motor winding; 2022 - Second three-phase bridge arm; S11 - First upper half-bridge switch; S12 - First lower half-bridge switch; S13 - Second upper half-bridge switch; S14 - Second lower half-bridge switch; S15 - Third upper half-bridge switch; S16 - Third lower half-bridge switch; S21 - Fourth upper half-bridge switch; S22 - Fourth lower half-bridge switch; S23 - Fifth upper half-bridge switch; S24 - Fifth lower half-bridge switch; S25 - Sixth upper half-bridge switch; S26 - Sixth lower half-bridge switch; L1 - The first phase motor winding in the first three-phase motor winding 2011; L2 - The second phase motor winding in the first three-phase motor winding 2011; L3 - The third phase motor winding in the first three-phase motor winding 2011; L4 - The first phase motor winding in the second three-phase motor winding 2021; L5 - The second phase motor winding in the second three-phase motor winding 2021; L6 - The third phase motor winding in the second three-phase motor winding 2021; K1 - First switch; K2 - Second switch; K3 - Third switch; K4 - Switch circuit; K5 - Fifth switch; K6 - Sixth switch; K7 - Seventh switch; K8 - Eighth switch; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; C4 - Fourth capacitor; R1 - First resistor; R2 - Second resistor; in+ - Positive connection terminal for high voltage DC input; in- - Negative connection terminal for high voltage DC input; out+ - Positive connection terminal for high voltage DC output; out-A - Negative connection terminal for the first high voltage DC output; out-B - Negative connection terminal for the second high voltage DC output; HV1+ - First electric drive bus terminal; HV2+ - Second electric drive bus terminal; HV1- - Third electric drive bus terminal; HV2- - Fourth electric drive bus terminal. Detailed Implementation

[0031] The terms “first,” “second,” etc., are used for descriptive purposes only and have no sequential or technical meaning, nor should they be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0032] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "coupled" and "connected" refer to the flow of current or signal from one conductor to another. A connection between A and B means that current or signal can flow from A to B and vice versa. A connection between A and B includes direct electrical connection and indirect electrical connection. A direct electrical connection between A and B means that A and B are electrically connected through physical contact. An indirect electrical connection between A and B means that A and B are electrically connected through C, where C can be at least one wire or device.

[0033] The embodiments of this application are described below with reference to the accompanying drawings.

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle disclosed in an embodiment of this application. Vehicle 1 can be, but is not limited to, a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), or a new energy vehicle.

[0035] In this embodiment, vehicle 1 includes a battery pack 10 and a charging circuit 20. The battery pack 10 is fixedly disposed at the bottom of the vehicle body, and the charging circuit 20 is disposed at the front-wheel drive and / or rear-wheel drive position of the vehicle body and is fixedly connected to the vehicle body. The battery pack 10 is connected to the charging circuit 20. When vehicle 1 is connected to a power supply device such as a charging pile, the charging pile charges the battery pack 10 through the charging circuit 20.

[0036] Please see Figure 2 , Figure 2 This is a schematic diagram of a charging circuit disclosed in an embodiment of this application. The charging circuit 20 includes: a first motor drive circuit 201, a second motor drive circuit 202, a control circuit 203, and a first charging port 204.

[0037] The first charging port 204 is coupled to the charging pile, the first motor drive circuit 201 is coupled to the first charging port 204, and the second motor drive circuit 202 is coupled to the battery pack 10. The control circuit 203 is coupled to the first motor drive circuit 201 and the second motor drive circuit 202.

[0038] In this embodiment of the application, the first motor drive circuit 201 is used to boost the voltage input to the first charging port 204 in order to charge the battery pack 10.

[0039] The first motor drive circuit 201 includes a first three-phase motor winding 2011, and the second motor drive circuit 202 includes a second three-phase motor winding 2021.

[0040] When the first motor drive circuit 201 is used to boost the charging of the battery pack 10, the control circuit 203 is used to control at least one phase of the second three-phase motor winding 2021 to connect with the first three-phase motor winding 2011, so as to increase the inductance in the boost circuit formed by the first motor drive circuit 201.

[0041] In this embodiment, the control circuit 203 controls the three-phase motor windings in the first motor drive circuit 201 and the second motor drive circuit 202 in a coordinated manner. When it is necessary to boost the voltage across the first charging port 204 and to boost the charging of the battery pack 10, at least one phase of the second three-phase motor winding 2021 is connected to the first three-phase motor winding 2011. This flexibly increases the equivalent inductance of the boost circuit, significantly improving the charging compatibility and stability between the low-voltage input and the battery pack 10, and avoiding problems such as excessive current ripple and voltage fluctuations caused by insufficient inductance of a single winding. Furthermore, this application optimizes the boost conversion efficiency by dynamically matching the inductance and reuses existing motor drive circuit resources, eliminating the need for additional independent inductors, simplifying the topology of the charging circuit 20, and improving space utilization.

[0042] It should be noted that the battery pack 10 is connected to the first motor drive circuit 201 and / or the second motor drive circuit 202. The battery pack 10 supplies power to the first motor drive circuit 201 and / or the second motor drive circuit 202. After receiving power, the first motor drive circuit 201 and / or the second motor drive circuit 202 convert electrical energy into mechanical energy to drive the vehicle 1 to move.

[0043] In some embodiments, in the charging circuit 20, the first motor drive circuit 201 further includes a first three-phase bridge arm 2012, and the second motor drive circuit 202 further includes a second three-phase bridge arm 2022. The first end of each phase motor winding in the first three-phase motor winding 2011 is correspondingly coupled to the midpoint of one phase bridge arm in the first three-phase bridge arm 2012. The second end of each phase motor winding in the first three-phase motor winding 2011 is commonly connected to a first common terminal. The first end of each phase motor winding in the second three-phase motor winding 2021 is correspondingly coupled to the midpoint of one phase bridge arm in the second three-phase bridge arm 2022. The second end of each phase motor winding in the second three-phase motor winding 2021 is commonly connected to a second common terminal.

[0044] In conjunction with the above embodiments, this application couples the first three-phase motor winding 2011 and the second three-phase motor winding 2021 to the midpoints of their respective three-phase bridge arms. Furthermore, the second ends of the first three-phase motor winding 2011 and the second three-phase motor winding 2021 are each shared. This application uses motor winding interconnection control; the control circuit 203 controls the precise on / off state and current direction of each phase winding in the three-phase bridge arms, providing reliable topological support for flexible adjustment of the equivalent inductance of the boost circuit, ensuring charging current stability, and reducing ripple interference.

[0045] Please see Figure 3 , Figure 3 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application. Figure 3 As shown, the first three-phase bridge arm 2012 includes: a first phase bridge arm, a second phase bridge arm, and a third phase bridge arm, and the second three-phase bridge arm 2022 includes: a fourth phase bridge arm, a fifth phase bridge arm, and a sixth phase bridge arm.

[0046] The first end of the first phase bridge arm, the first end of the second phase bridge arm, the first end of the third phase bridge arm, the first end of the fourth phase bridge arm, the first end of the fifth phase bridge arm, and the first end of the sixth phase bridge arm are all used to couple to the first end of the battery pack (also known as the positive terminal). The second end of the first phase bridge arm, the second end of the second phase bridge arm, the second end of the third phase bridge arm, the second end of the fourth phase bridge arm, the second end of the fifth phase bridge arm, and the second end of the sixth phase bridge arm are all used to couple to the second end of the battery pack (also known as the negative terminal).

[0047] The first three-phase motor winding 2011 includes: a first-phase motor winding L1, a second-phase motor winding L2, and a third-phase motor winding L3. The first end of the first-phase motor winding L1 is coupled to the midpoint of the first phase bridge arm. The first end of the second-phase motor winding L2 is coupled to the midpoint of the second phase bridge arm. The first end of the third-phase motor winding L3 is coupled to the midpoint of the third phase bridge arm. The second ends of the first-phase motor winding L1, the second end of the second-phase motor winding L2, and the second end of the third-phase motor winding L3 are all connected to a first common terminal.

[0048] The second three-phase motor winding 2021 includes: a first-phase motor winding L4, a second-phase motor winding L5, and a third-phase motor winding L6. The first end of the first-phase motor winding L4 is coupled to the midpoint of the fourth phase bridge arm. The first end of the fifth-phase motor winding L5 is coupled to the midpoint of the fifth phase bridge arm. The first end of the third-phase motor winding L6 is coupled to the midpoint of the sixth phase bridge arm. The second ends of the first-phase motor winding L4, the second ends of the second-phase motor winding L5, and the second ends of the third-phase motor winding L6 are all connected to a second common terminal.

[0049] The first phase bridge arm includes: a first upper half-bridge switch S11 and a first lower half-bridge switch S12; the second phase bridge arm includes: a second upper half-bridge switch S13 and a second lower half-bridge switch S14; the third phase bridge arm includes: a third upper half-bridge switch S15 and a third lower half-bridge switch S16; the fourth phase bridge arm includes: a fourth upper half-bridge switch S21 and a fourth lower half-bridge switch S22; the fifth phase bridge arm includes: a fifth upper half-bridge switch S23 and a fifth lower half-bridge switch S24; and the sixth phase bridge arm includes: a sixth upper half-bridge switch S25 and a sixth lower half-bridge switch S26. Each switch is connected in reverse parallel with a diode.

[0050] In the above embodiment, the control circuit 203 can control at least one phase of the second three-phase motor winding 2021 to be connected to the first three-phase motor winding 2011 by controlling the conduction state of each switch transistor, so as to increase the inductance in the boost circuit formed by the first motor drive circuit 201.

[0051] The charging circuit 20 further includes a first capacitor C1 and a second capacitor C2, wherein the first capacitor C1 is coupled between the first end and the second end of the first phase bridge arm, and the second capacitor C2 is coupled between the first end and the second end of the fourth phase bridge arm.

[0052] Both the first capacitor C1 and the second capacitor C2 are used to stabilize the voltage across the battery pack 10 and for filtering.

[0053] The charging circuit 20 also includes: a first switch K1 and a second switch K2.

[0054] The first switch K1 is coupled between the second motor drive circuit 202 and the negative terminal of the first charging port 204. The second switch K2 is coupled between the second terminal of the battery pack 10 and the negative terminal of the first charging port 204.

[0055] In DC charging mode, the control circuit 203 controls the first switch K1 to open and the second switch K2 to close, and the charging pile directly charges the battery pack 10 through the first charging port 204.

[0056] In boost charging mode, control circuit 203 controls the first switch K1 to close and the second switch K2 to open, and the charging pile charges the battery pack 10 through the boost circuit formed by the first motor drive circuit 201.

[0057] In some embodiments, since the charging pile needs to flow from a high voltage area to a low voltage area when charging the battery pack 10, when the voltage input by the charging pile is less than the voltage of the battery pack 10, it is necessary to ensure that the voltage across the first charging port 204 is less than the voltage input by the charging pile.

[0058] Therefore, the charging circuit 20 also includes a step-down circuit 205. The step-down circuit 205 is coupled between the positive terminal and the negative terminal of the first charging port 204.

[0059] When the voltage input to the charging pile is less than the voltage of the battery pack 10, the control circuit 203 controls the battery pack 10 to reduce the voltage across the step-down circuit through the first motor drive circuit, so that the voltage across the step-down circuit 205 is less than the voltage input to the charging pile.

[0060] The step-down circuit 205 includes: a third switch K3, a third capacitor C3, and a first resistor R1.

[0061] The first end of the third switch K3 is coupled to the positive terminal of the first charging port 204, the second end of the third switch K3 is coupled to the first end of the third capacitor C3 and the first end of the first resistor R1, and the second end of the third capacitor C3 and the second end of the first resistor R1 are coupled to the negative terminal of the first charging port 204 through the first switch K1.

[0062] Specifically, when the voltage input to the charging pile is less than the voltage of the battery pack 10, firstly, the control circuit 203 controls the first switch K1 to open, the second switch K2 to open, and the third switch K3 to close. Then, the control circuit 203 controls the battery pack 10 to reduce the voltage across the step-down circuit through the first motor drive circuit, that is, by controlling the first lower half-bridge switch S12, the second lower half-bridge switch S14, the third lower half-bridge switch S16, the fourth upper half-bridge switch S21, and the fourth lower half-bridge switch S2. 2. The fifth upper half-bridge switch S23, the fifth lower half-bridge switch S24, the sixth upper half-bridge switch S25, and the sixth lower half-bridge switch S26 are all disconnected, and the first upper half-bridge switch S11, the second upper half-bridge switch S13, and the third upper half-bridge switch S15 are controlled to operate in buck mode. That is, by controlling the duty cycle of the first upper half-bridge switch S11, the second upper half-bridge switch S13, and the third upper half-bridge switch S15, the voltage across the buck circuit 205 is made less than the voltage input to the charging pile.

[0063] In this embodiment, when the input voltage of the charging pile is lower than the voltage of the battery pack 10, the step-down circuit 205 set in the charging port can precisely step down the voltage by linking the first motor drive circuit 201 with the control circuit 203. This can ensure the safety of each electronic component in the charging circuit 20, reduce energy loss, dynamically adapt to multiple working conditions, and prevent reverse voltage from impacting the battery pack 10, thereby achieving safe, stable and efficient operation of charging the battery pack 10.

[0064] According to the above embodiments, the battery pack 10 can be connected to the first motor drive circuit 201 and the second motor drive circuit 202 respectively, so that the first motor drive circuit 201 and the second motor drive circuit 202 convert electrical energy into mechanical energy to drive the vehicle 1 to move after receiving power.

[0065] To retain this function of the first motor drive circuit 201 and the second motor drive circuit 202, a switching circuit K4 is also provided in the charging circuit 20. The switching circuit K4 is coupled between the first three-phase motor winding 2011 and the second three-phase motor winding 2021.

[0066] When the first motor drive circuit 201 and the second motor drive circuit 202 are used as a drive system, the control circuit 203 controls the switch K4 to open.

[0067] When the first motor drive circuit 201 is used to boost the charging of the battery pack 10, the control circuit 203 controls at least one phase of the second three-phase motor winding 2021 to be connected to the first three-phase motor winding 2011 through the switching circuit K4, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0068] In this embodiment, by setting a switching circuit K4 between the first three-phase motor winding 2011 and the second three-phase motor winding 2021, the on / off connection state between the two windings can be flexibly controlled. During boost charging, the switching circuit K4 is closed, interconnecting the first and second three-phase motor windings 2011 and 2021, increasing the equivalent inductance. During non-boost charging, the switching circuit K4 is open, allowing the motor drive circuit to operate independently and avoiding electrical interference between the motor windings. Furthermore, this embodiment eliminates the need for external inductors; the switching circuit K4 alone enables the reuse and function switching of the motor drive circuit, simplifying the topology and adapting to various vehicle operating conditions.

[0069] In this embodiment, the switching circuit K4 can be disposed between the first end of one phase of the first three-phase motor winding 2011 and the first end of one phase of the second three-phase motor winding 2021, or it can be disposed between the first end of one phase of the first three-phase motor winding 2011 and the second common terminal of the second three-phase motor winding 2021. When the switching circuit K4 is closed, the control circuit 203 controls the conduction state of each switching transistor, thereby controlling at least one phase of the second three-phase motor winding 2021 to connect with the first three-phase motor winding 2011, thereby increasing the inductance in the boost circuit formed by the first motor drive circuit 201.

[0070] The following is a detailed description of the three charging circuits 20 provided in the embodiments of this application.

[0071] Example 1: The switching circuit K4 is located between the first end of one phase of the first three-phase motor winding 2011 and the first end of one phase of the second three-phase motor winding 2021. When the first motor drive circuit is used to boost the charging of the battery pack 10, the control circuit 203 controls the first end of one phase of the second three-phase motor winding 2021 to be connected to the first end of one phase of the first three-phase motor winding 2011, and controls the first end of the other phase of the second three-phase motor winding 2021 to be connected to the negative terminal of the first charging port 204, so that one phase of the second three-phase motor winding 2021 and the other phase of the second three-phase motor winding 2021 and one phase of the first three-phase motor winding 2011 are connected in series, thereby increasing the inductance in the boost circuit formed by the first motor drive circuit.

[0072] Please refer to details. Figure 4 , Figure 4 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application. Figure 4As shown, the switching circuit K4 can be set between the first end of one phase of the motor winding in the first three-phase motor winding 2011 and the first end of one phase of the motor winding in the second three-phase motor winding 2021.

[0073] In boost charging mode, firstly, control circuit 203 controls the first switch K1 to close, the second switch K2 to open, and the third switch K3 to open. Then, it controls the fourth switch K4 to close. This is achieved by controlling the first lower half-bridge switch S12, the second lower half-bridge switch S14, the third lower half-bridge switch S16, the fourth upper half-bridge switch S21, the fourth lower half-bridge switch S22, the fifth upper half-bridge switch S23, the fifth lower half-bridge switch S24, the sixth upper half-bridge switch S25, and the sixth... All lower half-bridge switches S26 are disconnected, and the first upper half-bridge switches S11, the second upper half-bridge switches S13, and the third upper half-bridge switches S15 are controlled to operate in boost mode, so as to connect the first phase motor winding L4, the second phase motor winding L5 in the second three-phase motor winding 2021, and the third phase motor winding L3 in the first three-phase motor winding 2011 in the first three-phase motor winding 2011 in series, and boost charge the battery pack 10.

[0074] In this embodiment, the first phase motor winding L1 and the second phase motor winding L2 in the first three-phase motor winding 2011 are connected in parallel, and the third phase motor winding L3 in the first three-phase motor winding 2011, the first phase motor winding L4 in the second three-phase motor winding 2021, and the second phase motor winding L5 in the second three-phase motor winding 2021 are connected in series.

[0075] Under ideal conditions, the inductance in the boost circuit satisfies the following formula: H=(H1·H2) / (H1+H2)+H3+H4+H5; Wherein, H1 is the inductance of the first phase motor winding L1 in the first three-phase motor winding 2011, H2 is the inductance of the second phase motor winding L2 in the first three-phase motor winding 2011, H3 is the inductance of the third phase motor winding L3 in the first three-phase motor winding 2011, H4 is the inductance of the first phase motor winding L4 in the second three-phase motor winding 2021, and H5 is the inductance of the second phase motor winding L5 in the second three-phase motor winding 2021.

[0076] In this embodiment, during boost charging of the first motor drive circuit 201, two phases of the second three-phase motor winding 2021 are connected to one phase of the first three-phase motor winding 2011 and the negative terminal of the first charging port 204, respectively, forming a three-winding series structure, which significantly increases the equivalent inductance of the boost circuit. At this time, the vehicle operates in a boost charging state with optimal inductance allocation, maximizing the utilization of the equivalent inductance of the three-phase windings of the multi-motor module. This topology reduces the use of hardware such as relays in the DC boost charging circuit, improves the utilization rate of winding resistance and inductance in the multi-motor system, and effectively reduces electromagnetic interference problems, excessive motor temperature rise, and circuit hardware safety issues caused by excessive bus current ripple in the boost charging system. Simultaneously, it improves charging stability and energy conversion efficiency under low-voltage input, reuses existing winding resources without requiring additional inductors, simplifies the topology, reduces costs, and enhances the system's adaptability and reliability under different operating conditions.

[0077] Example 2: The switching circuit K4 is located between the first end of one phase of the first three-phase motor winding 2011 and the second common terminal of the second three-phase motor winding 2021. When the first motor drive circuit is used to boost the charging of the battery pack 10, the control circuit 203 controls the first end of one phase of the first three-phase motor winding 2011 to connect with the second common terminal, and controls the first end of at least one phase of the second three-phase motor winding 2021 to be connected to the negative terminal of the first charging port 204, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0078] Please refer to details. Figure 5 , Figure 5 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application. Figure 5 As shown, the switching circuit K4 is located between the first end of one phase of the first three-phase motor winding 2011 and the second common terminal of the second three-phase motor winding 2021. The second ends of the fourth phase bridge arm, the fifth phase bridge arm and the sixth phase bridge arm are coupled to the negative terminal of the first charging port 204.

[0079] Because the inductance in the boost circuit formed by the first motor drive circuit 201 is negatively correlated with the number of phases of the motor windings in the second three-phase motor winding 2021, the charging power for boost charging of the battery pack 10 is also negatively correlated with the inductance.

[0080] Therefore, in this embodiment of the application, the conduction state of each switch in the second motor drive circuit 202 can be controlled to make the first end of at least one phase motor winding in the second three-phase motor winding 2021 connected to the negative terminal of the first charging port 204.

[0081] In the boost mode of the first charging power, firstly, the control circuit 203 controls the first switch K1 to close, the second switch K2 to open, and the third switch K3 to open. Then, it controls the fourth switch K4 to close, and controls the first lower half-bridge switch S12, the second lower half-bridge switch S14, the third lower half-bridge switch S16, the fourth upper half-bridge switch S21, the fourth lower half-bridge switch S22, the fifth upper half-bridge switch S23, the fifth lower half-bridge switch S24, and the sixth upper half-bridge switch S25 to open. It also controls the first upper half-bridge switch S11, the second upper half-bridge switch S13, the third upper half-bridge switch S15, and the sixth lower half-bridge switch S26 to operate in boost mode, so as to connect the third phase motor winding L6 in the second three-phase motor winding 2021 in series with the third phase motor winding L3 in the first three-phase motor winding 2011, and boost charge the battery pack 10.

[0082] In this embodiment, the first phase motor winding L1 in the first three-phase motor winding 2011 and the second phase motor winding L2 in the first three-phase motor winding 2011 are connected in parallel, and the third phase motor winding L3 in the first three-phase motor winding 2011 and the third phase motor winding L6 in the second three-phase motor winding 2021 are connected in series.

[0083] Under ideal conditions, the inductance in the boost circuit satisfies the following formula: H=(H1·H2) / (H1+H2)+H3+H6; Wherein, H1 is the inductance of the first phase motor winding L1 in the first three-phase motor winding 2011, H2 is the inductance of the second phase motor winding L2 in the first three-phase motor winding 2011, H3 is the inductance of the third phase motor winding L3 in the first three-phase motor winding 2011, and H6 is the inductance of the third phase motor winding L6 in the second three-phase motor winding 2021.

[0084] In the boost mode of the second charging power, firstly, the control circuit 203 controls the first switch K1 to close, the second switch K2 to open, and the third switch K3 to open. Then, it controls the fourth switch K4 to close, and controls the first lower half-bridge switch S12, the second lower half-bridge switch S14, the third lower half-bridge switch S16, the fourth upper half-bridge switch S21, the fourth lower half-bridge switch S22, the fifth upper half-bridge switch S23, and the sixth upper half-bridge switch S25 to all open, and controls the first upper half-bridge switch to open. Switch S11, second upper bridge switch S13, third upper bridge switch S15, fifth lower bridge switch S24, and sixth lower bridge switch S26 operate in boost mode to connect the second phase motor winding L5 and the third phase motor winding L6 in the second three-phase motor winding 2021 in parallel, and then connect them in series with the third phase motor winding L3 in the first three-phase motor winding 2011 to boost charge the battery pack 10.

[0085] In this embodiment, the first phase motor winding L1 and the second phase motor winding L2 in the first three-phase motor winding 2011 are connected in parallel, the second phase motor winding L5 and the third phase motor winding L6 in the second three-phase motor winding 2021 are connected in parallel, and the third phase motor winding L3 in the first three-phase motor winding 2011 is connected in series in the boost circuit.

[0086] Under ideal conditions, the inductance in the boost circuit satisfies the following formula: H=(H1·H2) / (H1+H2)+H3+(H5·H6) / (H5+H6); Wherein, H1 is the inductance of the first phase motor winding L1 in the first three-phase motor winding 2011, H2 is the inductance of the second phase motor winding L2 in the first three-phase motor winding 2011, H3 is the inductance of the third phase motor winding L3 in the first three-phase motor winding 2011, H5 is the inductance of the second phase motor winding L5 in the second three-phase motor winding 2021, and H6 is the inductance of the third phase motor winding L6 in the second three-phase motor winding 2021.

[0087] In the boost mode of the third charging power, firstly, the control circuit 203 controls the first switch K1 to close, the second switch K2 to open, and the third switch K3 to open. Then, it controls the fourth switch K4 to close, and controls the first lower half-bridge switch S12, the second lower half-bridge switch S14, the third lower half-bridge switch S16, the fourth upper half-bridge switch S21, the fifth upper half-bridge switch S23, and the sixth upper half-bridge switch S25 to all open. It also controls the first upper half-bridge switch S11, the second upper half-bridge switch S13, and the third upper half-bridge switch S25 to open. Switch S15, fourth lower half-bridge switch S22, fifth lower half-bridge switch S24, and sixth lower half-bridge switch S26 operate in boost mode to connect the first phase motor winding L4, the second phase motor winding L5, and the third phase motor winding L6 in the second three-phase motor winding 2021 in parallel, and then connect them in series with the third phase motor winding L3 in the first three-phase motor winding 2011, thereby boosting the charging of the battery pack 10.

[0088] In this embodiment, the first phase motor winding L1 and the second phase motor winding L2 in the first three-phase motor winding 2011 are connected in parallel, the first phase motor winding L4, the second phase motor winding L5, and the third phase motor winding L6 in the second three-phase motor winding 2021 are connected in parallel, and the third phase motor winding L3 in the first three-phase motor winding 2011 is connected in series in the boost circuit.

[0089] Under ideal conditions, the inductance in the boost circuit satisfies the following formula: H=(H1·H2) / (H1+H2)+H3+(H4·H5·H6) / (H4·H5+ H5·H6+ H4·H6); Wherein, H1 is the inductance of the first phase motor winding L1 in the first three-phase motor winding 2011, H2 is the inductance of the second phase motor winding L2 in the first three-phase motor winding 2011, H3 is the inductance of the third phase motor winding L3 in the first three-phase motor winding 2011, H4 is the inductance of the first phase motor winding L4 in the second three-phase motor winding 2021, H5 is the inductance of the second phase motor winding L5 in the second three-phase motor winding 2021, and H6 is the inductance of the third phase motor winding L6 in the second three-phase motor winding 2021.

[0090] Since the inductance in the boost circuit formed by the first motor drive circuit 201 is negatively correlated with the number of phases of the motor windings in the second three-phase motor winding 2021, and the charging power for boost charging of the battery pack 10 is negatively correlated with the inductance, the first charging power is greater than the second and third charging power, and the second charging power is greater than the third charging power. In this embodiment, by controlling the first end of at least one phase of the second three-phase motor winding 2021 to be connected to the negative terminal of the first charging port 204, adjustable output power boost charging can be achieved.

[0091] In the above embodiments, by connecting the first end of one phase of the first three-phase motor winding 2011 to the second common terminal, and controlling at least one phase of the second three-phase motor winding 2021 to be connected to the negative terminal of the first charging port 204, the inductance resources of the second three-phase motor winding 2021 can be flexibly introduced without complex hardware modifications, rapidly increasing the equivalent inductance of the boost circuit. Furthermore, due to the correlation between inductance and charging power, the charging power can be adjusted. This approach precisely adapts to low-voltage input scenarios of charging piles, avoiding charging instability caused by insufficient inductance in a single winding. Simultaneously, it leverages existing motor drive topology to expand inductance without requiring additional independent inductors, simplifying the circuit structure, reducing costs, and ensuring the reliability and adaptability of boost charging.

[0092] In conjunction with the above embodiments, the inductance is negatively correlated with the number of phases connected to the second winding. This application can precisely match the optimal inductance value by increasing or decreasing the number of phases connected to the second winding, based on the charging pile input voltage, battery pack, and charging power requirements. This avoids both the slow charging dynamic response caused by excessive inductance and the ripple and loss problems caused by insufficient inductance, ensuring that the boost circuit always operates in the high-efficiency range, improving energy conversion efficiency, and enhancing control precision.

[0093] In addition, due to the negative correlation between charging power and inductance, the control circuit 203 can adjust the number of motor winding phases connected to the boost circuit according to the charging power requirements, so that the charging process is more in line with the charging characteristics of the battery pack, which not only ensures charging efficiency but also improves charging safety.

[0094] Example 3: The switching circuit K4 is located between the first end of one phase of the motor winding in the first three-phase motor winding 2011 and the first end of one phase of the motor winding in the second three-phase motor winding 2021. The charging circuit 20 also includes a second charging port 206, which is used to be coupled to the charging pile. The second motor drive circuit 202 is coupled to the second charging port 206 and is used to boost the voltage input to the second charging port 206 to charge the battery pack 10.

[0095] Please refer to details. Figure 6 , Figure 6 This is a schematic diagram of another charging circuit disclosed in an embodiment of this application. Figure 6 As shown, the charging circuit also includes a fifth switch K5, which is coupled between the second end of the fourth phase bridge arm and the second end of the battery pack 10.

[0096] When the first charging port 204 is connected to a charging pile and the second charging port 206 is not connected to a charging pile, the control circuit 203 can control the fourth switch K4 to open and the fifth switch K5 to open, so as to realize single-gun charging.

[0097] When the first charging port 204 is connected to the charging pile and the second charging port 206 is also connected to the charging pile, the control circuit 203 can control the fourth switch K4 to open and the fifth switch K5 to close, so as to realize dual-gun charging.

[0098] The charging circuit 20 also includes a sixth switch K6 and a seventh switch K7.

[0099] The sixth switch K6 is coupled between the second three-phase motor winding 2021 and the negative terminal of the second charging port 206. The seventh switch K7 is coupled between the second end of the sixth three-phase bridge arm and the negative terminal of the second charging port 206.

[0100] The charging circuit 20 further includes a second step-down circuit 207. The second step-down circuit 207 is coupled between the positive terminal of the second charging port 206 and the negative terminal of the second charging port 206.

[0101] The second step-down circuit 207 includes: an eighth switch K8, a fourth capacitor C4, and a second resistor R2.

[0102] The second step-down circuit 207 has a similar structure and function to the step-down circuit 205, and will not be described in detail here.

[0103] The following section introduces the DC charging mode and boost charging mode of the charging circuit 20, taking the example of both the first charging port 204 and the second charging port 206 being connected to a charging pile.

[0104] In DC charging mode, the control circuit 203 controls the first switch K1 to open, the second switch K2 to close, the sixth switch K6 to open, and the seventh switch K7 to close. The charging pile directly charges the battery pack 10 through the first charging port 204, and the charging pile also directly charges the battery pack 10 through the second charging port 206.

[0105] In boost charging mode, control circuit 203 controls the first switch K1 to close, the second switch K2 to open, the sixth switch K6 to close, and the seventh switch K7 to open. The charging pile charges the battery pack 10 through the boost circuit formed by the first motor drive circuit 201. The charging pile also charges the battery pack 10 through the boost circuit formed by the second motor drive circuit 202.

[0106] In the above embodiments, a second charging port 206 is added to the charging circuit 20, and the second motor drive circuit 202 is linked to achieve boost charging, which can significantly improve charging flexibility and redundancy reliability. It can support simultaneous access to two charging piles or selective access to a single charging pile, broadening the range of charging scenarios it can adapt to. Furthermore, in the event of a failure in any charging port or motor drive circuit, the charging function can be guaranteed to continue normally through the other path, avoiding charging interruptions. In addition, by reusing the boost resources of the second motor drive circuit 202, there is no need to add an additional independent boost module, simplifying the topology, reducing costs, and improving integration and charging efficiency.

[0107] To further illustrate the charging process, this application also provides a charging system.

[0108] Please see Figure 7 , Figure 7 This is a schematic diagram of a charging system disclosed in an embodiment of this application. The charging system 2 includes: a battery pack 10, a charging circuit 20, a battery controller 30, a vehicle controller 40, a port voltage sampling module 50, a bus voltage sampling module 60, and a charging pile 70.

[0109] The charging circuit 20 includes: a first motor drive circuit 201, a second motor drive circuit 202, a step-down circuit 205, a switching circuit K4, and a first switch K1 and a second switch K2.

[0110] The first motor drive circuit 201 includes: a first three-phase motor winding 2011 and a first three-phase bridge arm 2012.

[0111] The second motor drive circuit 202 includes: a second three-phase motor winding 2021 and a second three-phase bridge arm 2022.

[0112] The step-down circuit 205 includes: a third switch K3, a third capacitor C3, and a first resistor R1.

[0113] The charging pile 70 is equipped with a positive terminal in+ and a negative terminal in- for high voltage DC input. The battery pack 10 is equipped with a positive terminal out+ for high voltage DC output and a negative terminal out-B for the second high voltage DC output. The second three-phase motor winding 2021 is equipped with a negative terminal out-A for the first high voltage DC output.

[0114] The negative terminal in- of the high-voltage DC input is connected to the second terminal of the first switch K1 and the second terminal of the second switch K2. The negative terminal out-A of the first high-voltage DC output is connected to the first terminal of the first switch K1. The negative terminal out-B of the second high-voltage DC output is connected to the first terminal of the second switch K2.

[0115] The positive terminal in+ of the high-voltage DC input and the positive terminal out+ of the high-voltage DC output are connected to the first terminal of the third switch K3 in the step-down circuit 205, respectively. The second terminal of the third switch K3 is connected to the negative terminal out-A of the high-voltage DC output via the first resistor R1. The third capacitor C3 and the first resistor R1 are connected in parallel.

[0116] The first end of the battery pack 10 is connected to the first three-phase bridge arm 2012 via the first electric drive bus terminal HV1+, and is also connected to the second three-phase bridge arm 2022 via the second electric drive bus terminal HV2+. The second end of the battery pack 10 is connected to the first three-phase bridge arm 2012 via the third electric drive bus terminal HV1-, and is connected to the second three-phase bridge arm 2022 via the fourth electric drive bus terminal HV2-.

[0117] The first three-phase bridge arm 2012 and the second three-phase bridge arm 2022 are respectively connected to the first three-phase motor winding 2011 and the second three-phase motor winding 2021 via ribbon cables.

[0118] The port voltage sampling module 50 is coupled to both ends of the third capacitor C3.

[0119] The bus voltage sampling module 60 is coupled between the first electric drive bus terminal HV1+ and the third electric drive bus terminal HV1-, and / or coupled between the second electric drive bus terminal HV2+ and the fourth electric drive bus terminal HV2-, for the purpose of collecting bus voltage.

[0120] The switching circuit K4 is located between the first three-phase motor winding 2011 and the second three-phase motor winding 2021.

[0121] The vehicle controller 40 is connected to the battery controller 30, the first three-phase bridge arm 2012, the second three-phase bridge arm 2022, the step-down circuit 205, and the port voltage sampling module 50.

[0122] In this embodiment, the port voltage sampling module 50 is used to collect the voltage across the third capacitor C3 and transmit it to the vehicle controller 40 and the battery controller 30 via low-voltage communication.

[0123] The battery controller 30 is used to detect the voltage of the battery pack 10 and transmit it to the vehicle controller 40.

[0124] The vehicle controller 40 determines whether to step down the voltage across the step-down circuit 205 based on the voltage input from the charging pile 70 and the voltage of the battery pack 10.

[0125] When it is not necessary to reduce the voltage across the step-down circuit 205, the second switch K2 can be closed to DC charge the battery pack 10.

[0126] When it is necessary to reduce the voltage across the step-down circuit 205, the voltage across the step-down circuit 205 is reduced, and after the voltage is reduced, the battery pack 10 is boosted and charged.

[0127] The specific control logic can be found in the previous text, and will not be repeated here.

[0128] It should be noted that a main positive relay is provided at the first end of the battery pack 10 and a main negative relay is provided at the second end of the battery pack 10, as shown in the accompanying drawings disclosed in this application.

[0129] Based on such Figure 7 The charging system 2 shown is a control flow of a charging system disclosed in this application embodiment.

[0130] The control process of the charging system is mainly divided into three stages. First, the charging handshake stage requires establishing communication between the charging pile and the vehicle. Then, the charging identification stage requires identifying the charging pile information to determine whether to use DC charging or boost charging mode. Next, the charging ready stage involves the battery pack communicating with the charging pile through the charging circuit. Finally, the charging demand stage involves the charging pile using the charging circuit to perform boost charging to charge the battery pack.

[0131] Please refer to the charging handshake phase process. Figure 8 , Figure 8 This is a schematic diagram of the control flow of a charging system disclosed in an embodiment of this application.

[0132] During the charging handshake phase, the voltage during insulation testing of the charging pile is used to determine the maximum output capacity of the charging pile, enabling the vehicle to exchange information with the charging pile.

[0133] First, the charging gun on the charging pile side is connected to the vehicle's charging port (i.e., the first charging port and / or the second charging port in the charging circuit), and charging begins.

[0134] At this time, the battery controller (also known as the battery management system, BMS), on-board charger (OBC), and electric vehicle communication controller (EVCC) are in a dormant state.

[0135] The battery controller (also known as the battery management system, BMS) detects whether the physical connection with the charging station is abnormal.

[0136] Then, the vehicle side wakes up the EVCC via a Control Pilot (CP) signal, a Controller Area Network (CAN) message, or ignition switch key position 15 (KL15). The vehicle side also wakes up the OBC via a Connection Confirmation (CC) signal or KL15.

[0137] Next, EVCC cyclically sends the first message information (such as message 135) and determines the pulse-width modulation (PWM) value of the CP signal on the charging pile side, that is, the duty cycle of the CP signal.

[0138] When the duty cycle of the CP signal is between 3% and 7%, the DC charging process begins; when the duty cycle of the CP signal is between 9% and 97%, the AC charging process begins; when the duty cycle of the CP signal is less than 3% or greater than 97%, it is determined to be an invalid signal, and the process returns to continue detection.

[0139] During the DC charging process, under the European standard charging conditions overseas, the EVCC sends the A+ signal and the guide signal to start establishing communication with the Programmable Logic Controller (PLC).

[0140] Determine whether the BMS has received a valid A+ signal or a Charging Handshake Management (CHM) message.

[0141] If the BMS receives a valid A+ signal or CHM message, it proceeds to the next step; otherwise, it returns to continue testing. If a communication timeout occurs, a "charging stopped" message is sent to report the fault.

[0142] Next, the BMS sends a Bus Handshake Message (BHM) to the charging pile (usually containing information such as battery voltage) and detects the maximum voltage of the charging pile's insulation.

[0143] Next, the BMS checks whether the Charging Requirement Management (CRM) message on the charging pile side is at the first value and lasts for the first duration. If the communication times out, a "charging stopped" message is sent to report the fault information.

[0144] If the CRM message is valid, proceed to the charging identification stage; otherwise, return to continue testing. If communication times out, send a "charging stopped" message to report the fault.

[0145] In the above embodiments, if charging is not performed according to European standards overseas, there is no need to establish PLC communication; the BMS directly sends the BHM to the charging pile.

[0146] Please refer to the charging identification process. Figure 9 , Figure 9 This application discloses a schematic diagram of the control flow of another charging system.

[0147] After the BMS stops sending BHM, it sends a battery-related message (BRM) to the charging pile (which usually contains battery-related information and the vehicle charging protocol version, etc.).

[0148] The BMS checks whether it receives CRM messages from the charging pile side, and whether the CRM message is the second value and lasts for the second duration. If the communication times out, it sends a "charging stopped" message to report the fault information.

[0149] If a CRM message is received from the charging pile side, and the CRM message does not have the second value and lasts for the second duration, then proceed to the next step; otherwise, return to continue sending BRM messages to the charging pile.

[0150] The BMS determines whether the maximum voltage of the charging pile insulation test is less than the preset value. If it is less than the preset value, it enters the charging ready stage; otherwise, it enters the DC charging process.

[0151] Please refer to the charging readiness phase process. Figure 10 , Figure 10 This is a schematic diagram of the control flow of another charging system disclosed in an embodiment of this application.

[0152] When boost charging is in progress, the BMS stops sending the BRM and instead sends the Battery Charging Protocol (BCP) to the charging station (which typically includes the maximum charging voltage, maximum charging current, battery pack voltage, etc.).

[0153] Among them, the battery pack voltage is the minimum value between the battery pack voltage minus the minimum boost voltage difference and the preset target charging port voltage.

[0154] BMS detects whether it receives Charging Timing Control (CTS) messages and Charging Message Log (CML) messages from the charging pile within the third time period.

[0155] If the CTS message and CML are valid, the BMS sends a Battery RelayOutput (BRO) message to the charging station. The BRO message is used to indicate that the charging station is not ready.

[0156] The battery controller and charging pile information verification is successful, and a command is sent to the multi-motor high-voltage DC transformer module. It then checks whether the voltage difference across the third switch is greater than a preset value and remains so for a third duration.

[0157] If the voltage difference across the third switch is greater than the preset value and continues for a third duration, the third switch will be closed; otherwise, a "charging stopped" message will be sent and fault information will be fed back.

[0158] Next, it is determined whether the pressure difference across the first switch is greater than the set value and continues for a fourth time period.

[0159] If the voltage difference across the first switch exceeds the set value and remains so for four consecutive hours, the first switch will be closed. Otherwise, a "charging stopped" message will be sent along with fault information.

[0160] Next, the BMS sends a high-voltage request and closes the main positive relay and the main negative relay.

[0161] To determine whether high-voltage power-on is complete, if so, the BMS requests the first motor drive circuit to enter buck mode, sends the required transformer voltage, and closes the switching circuit. At the same time, it controls the second motor drive circuit to enter high-voltage standby mode.

[0162] The transformer required voltage is the minimum value of the battery pack voltage minus the minimum boost voltage difference and the preset target charging port voltage for bucking.

[0163] The first motor drive circuit operates in buck mode, controlling the charging port voltage to reach the transformer's required voltage. It then determines whether the voltage across the third capacitor is controlled within the preset range of the transformer's required voltage within the fifth time interval.

[0164] If the voltage across the third capacitor is controlled within the preset range of the transformer's required voltage within the fifth time period, the BMS sends a BRO message to the charging pile, indicating that it is ready. Otherwise, it sends a "charging stopped" message and reports a fault.

[0165] Determine whether the BMS has received a Charge Request Order (CRO) message from the charging pile side. The CRO message is used to indicate that the charging pile is ready.

[0166] If the BMS receives a CRO message from the charging pile side, it enters the charging demand phase. Otherwise, it sends a "charging stopped" message and reports a fault.

[0167] Please refer to the charging demand phase process. Figure 11 , Figure 11 This is a schematic diagram of the control flow of another charging system disclosed in an embodiment of this application.

[0168] The BMS stops sending BRO messages and sends the battery charge load (BCL) (which typically includes transformer demand voltage and transformer demand current) to the first motor drive circuit and the second motor drive circuit.

[0169] Determine whether the first motor drive circuit and the second motor drive circuit switch from electric drive transformer output mode to boost mode within the sixth time period.

[0170] If the circuit switches from electric drive transformer output mode to boost mode within the sixth time period, the BMS sends a Battery Charging Specification (BCM) message (usually including voltage and current acquisition values, forwarded charging port voltage, and transformer input current) to the first motor drive circuit and the second motor drive circuit. The first motor drive circuit and the second motor drive circuit then perform closed-loop control on the bus voltage, charging port voltage, and transformer output current.

[0171] Specifically, the target voltage for the charging port is the minimum of the sum of the current battery pack voltage, the minimum allowable output voltage of the boost converter, and the minimum input voltage difference, plus the preset target charging port voltage. The target bus voltage is the sum of the current battery pack voltage and the allowable output voltage of the boost converter, minus the minimum input voltage difference. The target transformer output current is the minimum of the maximum output current of the charging pile and the current required by the battery pack transformer. These parameters are updated in real time during the charging process.

[0172] Next, it is determined whether the output current detected by the BMS within the seventh time period is greater than the preset current.

[0173] If the BMS detects that the output current is greater than the preset current within the seventh time period, it will disconnect the third switch and update the transformer demand voltage and transformer demand current in the BCS message. Otherwise, it will re-detect.

[0174] Next, the BMS checks whether the output current of the charging pile meets the target current value.

[0175] If the BMS detects that the charging pile's output current meets the target current value, the BMS requests the first motor drive circuit and the second motor drive circuit to enter a no-request mode and controls the first switch, the third switch, and the switch circuit to disconnect. Otherwise, it re-detects.

[0176] Next, charging statistics are sent, and charging is complete.

[0177] Based on the control flow of the charging system provided in the embodiments of this application, it can be compatible with the boost charging of overseas European standard charging piles and Chinese standard charging piles, and solve the charging problem caused by overvoltage or undervoltage at the charging pile port of European standard medium voltage charging piles.

[0178] In the above embodiments, during the closed-loop control process of the first motor drive circuit and the second motor drive circuit on the bus voltage, charging port voltage, and transformer output current, the three-loop control diagram is shown below. Figure 12 As shown.

[0179] The drive system consists of a first motor drive circuit and a second motor drive circuit.

[0180] The charging port voltage loop, bus voltage loop, and transformer output current loop are all composed of a proportional-integral (PI) controller and a multiplier.

[0181] The port voltage sampling module and the step-down module collect the feedback voltage of the charging port and send it to the charging port voltage loop.

[0182] The bus voltage acquisition module acquires the feedback voltage of the bus voltage from the drive system consisting of the first motor drive circuit and the second motor drive circuit, and sends it to the bus voltage loop.

[0183] The transformer output current sensor collects the feedback current of the transformer output current from the output terminal of the drive system and sends it to the transformer output current loop.

[0184] The charging port voltage loop obtains the target voltage U1 of the charging port from the battery pack, and then calculates the target voltage U1 of the charging port and the feedback voltage U1 of the charging port. fed Error voltage U1 between err The first modulation signal is output.

[0185] The bus voltage loop obtains the target bus voltage U2 from the battery pack, and then calculates the bus voltage based on the target bus voltage U2 and the feedback bus voltage U2. fed Error voltage U2 between err The second modulation signal is output.

[0186] The transformer output current loop obtains the target current I from the battery pack, and then calculates the output current based on the target current I and the feedback current I of the transformer output current.fed Error current I between err The third modulation signal is output.

[0187] The first modulation signal and the second modulation signal are input to the logic OR operation unit, and the output result is output to the extreme value selection unit.

[0188] The third modulation signal is output to the extreme value selection unit, which then outputs the drive signal to the drive system.

[0189] The extreme value selection unit is used to select the maximum or minimum value.

[0190] This application provides a control method for a charging circuit, applied to the charging circuit shown in the above embodiment. When the first motor drive circuit is used to boost the charging of the battery pack, at least one phase of the second three-phase motor winding is controlled to be connected to the first three-phase motor winding to increase the inductance in the boost circuit formed by the first motor drive circuit 201.

[0191] In some embodiments, the control method of the charging circuit further includes: when the first motor drive circuit is used to boost the charging of the battery pack, controlling at least one phase of the second three-phase motor winding to connect with the first three-phase motor winding 2011 through a switching circuit, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

[0192] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A charging circuit, characterized in that, The charging circuit is used for charging the battery pack of a vehicle, and includes: The first charging port (204) is used to be coupled to the charging pile; A first motor drive circuit (201) is coupled to the first charging port (204) and is used to boost the voltage input to the first charging port (204) to charge the battery pack. The first motor drive circuit (201) includes a first three-phase motor winding (2011). A second motor drive circuit (202) is used to couple to the battery pack, the second motor drive circuit (202) including a second three-phase motor winding (2021). The control circuit (203), coupled to the first motor drive circuit (201) and the second motor drive circuit (202), is configured to: when the first motor drive circuit (201) is used to boost charge the battery pack, control at least one phase of the second three-phase motor winding (2021) to connect to the first three-phase motor winding (2011) to increase the inductance in the boost circuit formed by the first motor drive circuit (201).

2. The charging circuit according to claim 1, characterized in that, The first motor drive circuit (201) further includes a first three-phase bridge arm (2012), the first end of each phase motor winding in the first three-phase motor winding (2011) is correspondingly coupled to the midpoint of one phase bridge arm in the first three-phase bridge arm (2012), and the second end of each phase motor winding in the first three-phase motor winding (2011) is connected to the first common connection end. The second motor drive circuit (202) further includes a second three-phase bridge arm (2022), the first end of each phase motor winding in the second three-phase motor winding (2021) is correspondingly coupled to the midpoint of one phase bridge arm in the second three-phase bridge arm (2022), and the second end of each phase motor winding in the second three-phase motor winding (2021) is connected to the second common terminal.

3. The charging circuit according to claim 2, characterized in that, The control circuit (203) is specifically configured as follows: When the first motor drive circuit (201) is used to boost the charging of the battery pack, the first end of the first phase motor winding in the second three-phase motor winding (2021) is connected to the first end of the first phase motor winding in the first three-phase motor winding (2011); and the first end of the second phase motor winding in the second three-phase motor winding (2021) is connected to the negative terminal of the first charging port (204), so that the first phase motor winding and the second phase motor winding in the second three-phase motor winding (2021) and the first phase motor winding in the first three-phase motor winding (2011) are connected in series, so as to increase the inductance in the boost circuit formed by the first motor drive circuit (201); the first phase motor winding and the second phase motor winding in the second three-phase motor winding (2021) are any two phase motor windings in the second three-phase motor winding (2021).

4. The charging circuit according to claim 2, characterized in that, The control circuit (203) is specifically configured as follows: When the first motor drive circuit (201) is used to boost the charging of the battery pack, it controls the first end of one phase of the first three-phase motor winding (2011) to be connected to the second common terminal, and controls the first end of at least one phase of the second three-phase motor winding (2021) to be connected to the negative terminal of the first charging port (204) to increase the inductance in the boost circuit formed by the first motor drive circuit (201).

5. The charging circuit according to claim 4, characterized in that, The inductance in the boost circuit formed by the first motor drive circuit (201) is negatively correlated with the number of phases of the motor windings in the second three-phase motor winding (2021).

6. The charging circuit according to claim 4, characterized in that, The charging power for boost charging of the battery pack is negatively correlated with the inductance.

7. The charging circuit according to claim 2, characterized in that, Also includes: The second charging port (206) is used to be coupled to the charging pile; The second motor drive circuit (202) is coupled to the second charging port (206) and is used to boost the voltage input to the second charging port (206) to charge the battery pack.

8. The charging circuit according to claim 1, characterized in that, Also includes: A switching circuit is coupled between the first three-phase motor winding (2011) and the second three-phase motor winding (2021); the control circuit (203) is specifically configured as follows: When the first motor drive circuit (201) is used to boost the charging of the battery pack, the switching circuit controls at least one phase of the second three-phase motor winding (2021) to connect with the first three-phase motor winding (2011) to increase the inductance in the boost circuit formed by the first motor drive circuit (201).

9. The charging circuit according to claim 2, characterized in that, Also includes: A step-down circuit (205) is coupled between the positive terminal of the first charging port (204) and the negative terminal of the first charging port (204); The control circuit (203) is also configured to: when the voltage input to the charging pile is less than the voltage of the battery pack, control the battery pack to reduce the voltage across the step-down circuit (205) through the first motor drive circuit (201).

10. A control method for a charging circuit, characterized in that, The charging circuit includes: a first charging port, a first motor drive circuit, and a second motor drive circuit. The first charging port is coupled to a charging pile. The first motor drive circuit is coupled to the first charging port and is used to boost the voltage input to the first charging port to charge the battery pack. The second motor drive circuit is coupled to the battery pack. The first motor drive circuit includes a first three-phase motor winding, and the second motor drive circuit includes a second three-phase motor winding. When the first motor drive circuit is used to boost the charging of the battery pack, it controls at least one phase of the second three-phase motor winding to be connected to the first three-phase motor winding, so as to increase the inductance in the boost circuit formed by the first motor drive circuit.

11. The control method for the charging circuit according to claim 10, characterized in that, The charging circuit further includes a switching circuit coupled between the first three-phase motor winding and the second three-phase motor winding; the method further includes: When the first motor drive circuit is used to boost the charging of the battery pack, the switching circuit controls at least one phase of the second three-phase motor winding to connect with the first three-phase motor winding, thereby increasing the inductance in the boost circuit formed by the first motor drive circuit.

12. A vehicle, characterized in that, Includes the charging circuit as described in any one of claims 1-9.

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