Charging / discharging circuit, system, and control method thereof

Abstract

To provide a charging / discharging circuit, a system, and a control method thereof.SOLUTION: The charging / discharging circuit includes: a power supply module including at least a first battery pack; an inverter module including an M-phase bridge arm, where M is a positive integer greater than 0; a charge / discharge control module including a charge / discharge circuit switching bridge arm; and a drive module including an M-phase motor, in which the first battery pack, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm are connected in parallel, upper and lower bridge arm connection points of the M-phase bridge arm are connected in one-to-one correspondence to the M-phase winding of the M-phase motor, and upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor. By connecting the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm to the M-phase motor, the magnitude and phase of the current flowing through the M-phase motor can be the same, thereby avoiding noise caused by uneven stator magnetic fields during motor overheating.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present application relates to the technical field of batteries, and more particularly to a charging and discharging circuit, a system and a control method thereof. [Background technology]

[0002] Due to their advantages of high energy density, rechargeability, safety and environmental friendliness, power batteries are widely used in fields such as new energy vehicles, consumer electronics and energy storage systems.

[0003] However, the use of power batteries in low-temperature environments has certain limitations. Specifically, the discharge capacity of power batteries in low-temperature environments is seriously degraded, and the batteries cannot be charged in low-temperature environments. Therefore, in order to use the power batteries normally, it is necessary to heat the power batteries in low-temperature environments.

[0004] In the conventional power battery heating technology, the motor circuit is used to heat the power battery, which may cause the problem of excessive motor vibration noise. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments of the present application provide a charging / discharging circuit, a system, and a control method thereof, which can effectively suppress motor vibration noise when heating a battery using a motor circuit. [Means for solving the problem]

[0006] In a first aspect, a charge / discharge circuit is provided, comprising: a power supply module, an inverter module, a charge / discharge control module, and a drive module, wherein the power supply module includes at least a first battery pack; the inverter module includes an M-phase bridge arm, where M is a positive integer greater than 0; the charge / discharge control module includes a charge / discharge circuit switching bridge arm; and the drive module includes an M-phase motor, wherein the first battery pack, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm are connected in parallel, and upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected in one-to-one correspondence to an M-phase winding of the M-phase motor, and the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor.

[0007] By connecting the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm to the M-phase motor, the magnitude and phase of the current flowing through the M-phase motor are allowed to be the same, thereby avoiding noise caused by uneven stator magnetic field when the motor is overheating.

[0008] In a second aspect, a charge / discharge circuit is provided, comprising: a power supply module, an inverter module, a charge / discharge control module, a drive module, and a switch unit, wherein the power supply module includes at least a first battery pack and a second battery pack; the inverter module includes an M-phase bridge arm, where M is a positive integer greater than 0; the charge / discharge control module includes a charge / discharge circuit switching bridge arm; the drive module includes an M-phase motor; the first battery pack and the M-phase bridge arm are connected in parallel; a first end of the first battery pack and an upper bridge arm of the M-phase bridge arm are collinearly connected; upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to M-phase windings of the M-phase motor in a one-to-one correspondence; upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor; a first end of the second battery pack is collinearly connected to the upper bridge arm of the charge / discharge circuit switching bridge arm; and a second end of the second battery pack is collinearly connected to a second end of the first battery pack, the M-phase bridge arm, and the lower bridge arm of the charge / discharge circuit switching bridge arm; and the switch unit is disposed between the first end of the first battery pack and the first end of the second battery pack.

[0009] The charge / discharge circuit switching bridge arm can switch the flow direction of the output current of the M-phase motor, thereby controlling the charge / discharge process of the power supply unit. This can increase the magnitude of the charging current and improve charging efficiency when the M-phase motor circuit is used to heat the power supply module. In addition, by connecting the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm to the M-phase motor, the M-phase motor can generate zero-sequence current, thereby preventing rotor heating and further demagnetization caused by magnetic field non-uniformity when the motor is running.

[0010] In one possible embodiment, at least one external inductance unit is installed between the M-phase motor and the charge / discharge circuit switching bridge arm.

[0011] In one possible embodiment, the connection point of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm is connected to one end of at least one external inductance unit, and the other end of the at least one external inductance unit is connected to the M-phase winding connection point of the M-phase motor.

[0012] The installation of an external energy storage element can effectively improve the impedance of the energy storage element, such as the motor winding, so that the charging and discharging current of the power supply module can be stably maintained at a high level, thereby effectively improving the charging and discharging efficiency of the power supply module and the heating rate of the battery.

[0013] In one possible embodiment, the M-phase motor is a double motor and includes a first M-phase motor and a second M-phase motor, where the M-phase winding connection points of the first M-phase motor are connected to the M-phase winding connection points of the second M-phase motor.

[0014] In one possible embodiment, the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the M-phase windings of the first M-phase motor in one-to-one correspondence.

[0015] In one possible embodiment, the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are respectively connected to the M-phase windings of the second M-phase motor in one-to-one correspondence.

[0016] By connecting the winding connection points of the double motor and simultaneously controlling the conduction switching of the motor controller, the current flowing into the motor and the current flowing out of the motor are controlled to always maintain the same direction, thereby minimizing the composite magnetic field generated by the windings during the motor heating process, effectively reducing motor vibration noise and rotor heat generation problems.

[0017] In a third aspect, a charging / discharging system is provided, the system including a control module and the charging / discharging circuit, the control module being used to send commands to the charging / discharging circuit to control the charging / discharging of the power supply module.

[0018] In a fourth aspect, a charge / discharge control method is provided for an electrical system, the electrical system including a control module and a charge / discharge circuit, the charge / discharge circuit including a power supply module, an inverter module, a charge / discharge control module, and a drive module, wherein the power supply module includes at least a first battery pack, the inverter module includes an M-phase bridge arm, where M is a positive integer greater than 0, the charge / discharge control module includes a charge / discharge circuit switching bridge arm, and the drive module includes an M-phase motor, the first battery pack, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm are connected in parallel, and The bridge arm connection points are respectively connected to M-phase windings of the M-phase motor in a one-to-one correspondence, and upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor, and the method includes, in response to an enable signal sent from the controller, making either the upper bridge arm or the lower bridge arm of the M-phase bridge arm conductive, and making either the upper bridge arm or the lower bridge arm of the charge / discharge circuit switching bridge arm conductive, thereby forming a charge circuit or a discharge circuit, and repeatedly switching between the charge circuit or the discharge circuit, thereby charging and discharging the power supply module.

[0019] In a fifth aspect, there is provided a charge / discharge control method for an electrical system, the electrical system including a control module and a charge / discharge circuit, the charge / discharge circuit including a power supply module, an inverter module, a charge / discharge control module, a drive module and a switch unit, wherein the power supply module includes at least a first battery pack and a second battery pack, the inverter module includes an M-phase bridge arm, M is a positive integer greater than 0, the charge / discharge control module includes a charge / discharge circuit switching bridge arm, the drive module includes an M-phase motor, the first battery pack and the M-phase bridge arm are connected in parallel, a first end of the first battery pack and an upper bridge arm of the M-phase bridge arm are connected in a collinear manner, connection points of the upper and lower bridge arms of the M-phase bridge arm are respectively connected to an M-phase winding of the M-phase motor in a one-to-one correspondence, the connection points of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm are connected to the M-phase motor, and a first end of the second battery pack is connected to the charge / discharge circuit switching bridge arm. a second end of the second battery pack is collinearly connected to the upper bridge arm of the M-phase bridge arm, a second end of the second battery pack is collinearly connected to the second end of the first battery pack, the M-phase bridge arm, and the lower bridge arm of the charge / discharge circuit switching bridge arm; a switch unit is disposed between the first end of the first battery pack and the first end of the second battery pack; and the method includes, in response to an enable signal sent from the controller, making the upper bridge arm or the lower bridge arm of the M-phase bridge arm conductive, and making the upper bridge arm or the lower bridge arm of the charge / discharge circuit switching bridge arm conductive, thereby forming a charging circuit and a discharging circuit, and charging / discharging the first battery pack and the second battery pack through the charging circuit and the discharging circuit, wherein the charging / discharging includes switching the charging / discharging states of the first battery pack and the second battery pack, and wherein the charging / discharging state includes charging the first battery pack and simultaneously discharging the second battery pack, or discharging the first battery pack and simultaneously charging the second battery pack.

[0020] By controlling the upper and lower bridge arms of the M-phase bridge arm with the control module, the phase and magnitude of the winding current of the M-phase motor are the same, thereby avoiding noise and rotor heat caused by magnetic field non-uniformity when the motor is running, and preventing motor demagnetization. Furthermore, the installation of dual batteries effectively reduces the constraints on the heating current magnitude and frequency imposed by the motor inductance. The dual-battery heating method allows the energy of the energy storage element to be released to one of the batteries in a timely manner, so that the battery heating current can be maintained at a stable magnitude according to the preset heating frequency. This allows the battery to significantly improve heating speed by adjusting the heating current frequency at different temperatures and SOC states. [Brief explanation of the drawings]

[0021] In order to more clearly explain the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on the drawings without any creative work. [Figure 1] FIG. 1 is a circuit diagram of a conventional charge / discharge circuit. [Figure 2] FIG. 2 is a schematic block diagram of a discharge circuit provided by an embodiment of the present application. [Figure 3] FIG. 3 is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 3a] FIG. 3a is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 3b] FIG. 3b is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 3c] FIG. 3c is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 4] FIG. 4 is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 4a] FIG. 4a is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 4b] FIG. 4b is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 4c] FIG. 4c is a circuit diagram of a charging / discharging circuit provided in an embodiment of the present application. [Figure 5] FIG. 5 is a schematic block diagram of a charging / discharging system provided by an embodiment of the present application. [Figure 6] FIG. 6 is a flowchart of a control method for a power battery heating scenario provided by an embodiment of the present application. [Figure 7] FIG. 7 is a schematic block diagram of a charge / discharge control device provided in an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0022] The embodiments of the present application will be described in more detail below with reference to the drawings and examples. The detailed description of the following examples and the drawings are used to exemplify the principles of the present application, but are not intended to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0023] In describing this application, it should be explained that, unless otherwise specified, "plurality" means two or more, and any designated orientations or positional relationships, such as the terms "up," "down," "left," "right," "inside," "outside," etc., are merely for the purpose of explaining and simplifying the description of this application, and do not indicate or imply that a specified device or element must have a particular orientation, be configured, or operate in a particular orientation, and therefore should not be understood as limiting this application. Additionally, the terms "first," "second," "third," etc. are used merely to describe the purpose and should not be understood to indicate or imply relative importance. "Perpendicular" does not mean perpendicular in the strict sense, but within a margin of error. "Parallel" does not mean parallel in the strict sense, but within a margin of error.

[0024] All directional terms used in the following description refer to the directions shown in the drawings and do not limit the specific structure of the present application. It should be further explained that in the description of the present application, unless otherwise clearly specified or limited, the terms "attached," "communicating," and "connected" should be understood in a broad sense, and may refer to, for example, fixed connection, detachable connection, or integral connection, direct communication, or indirect communication via an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0025] With the development of the times, new energy vehicles have huge market potential due to their advantages such as environmental friendliness, low noise and low usage costs, and can effectively promote energy conservation and emission reduction, thereby contributing to the development and progress of society.

[0026] Due to the electrochemical characteristics of the power battery, the charge and discharge capacity of the power battery is significantly limited in low temperature environments, which seriously affects the winter driving experience of customers. Therefore, in order to ensure normal use of the power battery, it is necessary to heat the power battery in low temperature environments.

[0027] The power battery in the embodiments of the present application may be a lithium ion battery, a lithium metal battery, a lead acid battery, a nickel cadmium battery, a nickel metal hydride battery, a lithium sulfur battery, a lithium air battery, or a sodium ion battery, etc., and is not limited thereto. In terms of scale, the battery in the embodiments of the present application may be a single cell, a battery module, or a battery pack, and is not limited thereto. In terms of application scenarios, the battery can be used in power plants such as automobiles and ships. For example, it can be used in a power vehicle to supply power to the motor of the power vehicle and serve as the power source for the electric vehicle. The battery can also supply power to other electrical devices in the electric vehicle, such as the in-vehicle air conditioner and on-board player.

[0028] For ease of explanation, the application of the power battery to a new energy vehicle (powered vehicle) will be taken as an example below.

[0029] The drive motor and its control system are one of the core components of new energy vehicles, and their drive characteristics determine the main performance indicators of vehicle operation. The motor drive system of a new energy vehicle mainly consists of an electric motor (i.e., motor), a motor controller (e.g., inverter), various detection sensors, and a power supply. A motor is a rotating electromagnetic machine that operates using the principle of electromagnetic induction and is used to convert electrical energy into mechanical energy. During operation, it absorbs power from the electrical system and outputs mechanical power to the mechanical system.

[0030] In order to avoid unnecessary increase in costs when heating the power battery, the motor circuit can be used to heat the power battery.

[0031] 1 shows a charging and discharging circuit diagram of a conventional power battery heating system. As shown in FIG. 1, the power battery heating system 100 can include a power supply module 110, an inverter module 120 connected to the power supply module 110, and a driving module 130 connected to the inverter module 120.

[0032] The power supply module 110 can be realized not only by using the power battery itself but also by using an external power supply module, such as a charging pile. The heating energy provided by the external power supply module can be, for example, externally connected to a DC charger and output, or externally connected to an AC charger and output after rectification, and is not specifically limited here.

[0033] The inverter module 120 can be implemented using various types of switches. For example, the inverter module 120 can be implemented by an inverter in a motor drive system, where the inverter can be implemented by bridge arm switches of insulated gate bipolar transistors (IGBTs). Specifically, the number of bridge arms of the inverter is the same as the number of windings in the drive module 130. For example, the drive module 130 includes a three-phase winding motor, and the inverter includes three-phase bridge arms, namely, a U-phase bridge arm, a V-phase bridge arm, and a W-phase bridge arm. Here, each bridge arm in the three-phase bridge arms has an upper bridge arm and a lower bridge arm, and the upper bridge arm and lower bridge arm are respectively provided with switch units. That is, the inverter module 120 includes an upper bridge arm switch 121 and a lower bridge arm switch 122 in the U-phase bridge arm, an upper bridge arm switch 123 and a lower bridge arm switch 124 in the V-phase bridge arm, and an upper bridge arm switch 125 and a lower bridge arm switch 126 in the W-phase bridge arm.

[0034] Specifically, the drive module 130 may include a winding 131 connected to the U-phase bridge arm, a winding 132 connected to the V-phase bridge arm, and a winding 133 connected to the W-phase bridge arm. One end of the winding 131 is connected to the connection point between the upper and lower bridge arms of the U-phase bridge arm, one end of the winding 132 is connected to the connection point between the upper and lower bridge arms of the V-phase bridge arm, and one end of the winding 133 is connected to the connection point between the upper and lower bridge arms of the W-phase bridge arm. The other end of the winding 131, the other end of the winding 132, and the other end of the winding 133 are connected by the same wire.

[0035] It should be noted that the driving module 130 is not limited to a three-phase winding motor, but may be a six-phase winding motor, etc. Correspondingly, the inverter module 120 may include a three-phase bridge arm or a six-phase bridge arm.

[0036] In some embodiments, the current can be modulated by controlling the periodic on / off of switches in inverter module 120. For example, the current is modulated by controlling the periodic on / off of a target upper bridge arm switch and a target lower bridge arm switch in inverter module 120. In one example, if the target upper bridge arm switch is upper bridge arm switch 121, the target lower bridge arm switch is lower bridge arm switch 124 and / or lower bridge arm switch 126. In another example, if the target upper bridge arm switch is upper bridge arm switch 123, the target lower bridge arm switch is lower bridge arm switch 122 and / or lower bridge arm switch 126. In another example, if the target upper bridge arm switch is upper bridge arm switch 125, the target lower bridge arm switch is lower bridge arm switch 122 and / or lower bridge arm switch 124. In another example, if the target upper bridge arm switch is upper bridge arm switch 121 and / or upper bridge arm switch 123, the target lower bridge arm switch is lower bridge arm switch 126. In another example, if the target upper bridge arm switch is upper bridge arm switch 123 and / or upper bridge arm switch 125, the target lower bridge arm switch is lower bridge arm switch 122. In another example, if the target upper bridge arm switch is upper bridge arm switch 121 and / or upper bridge arm switch 125, the target lower bridge arm switch is lower bridge arm switch 124.

[0037] Note that the target upper bridge arm switch and the target lower bridge arm switch may be turned on and off periodically in each cycle, and may be the same or different, and are not limited thereto. For example, the upper bridge arm switch 121 and the lower bridge arm switch 124 are both controlled on and off in each cycle. For example, the upper bridge arm switch 121 and the lower bridge arm switch 124 are controlled on and off in a first cycle, the upper bridge arm switch 123 and the lower bridge arm switch 122 are controlled on and off in a second cycle, and the upper bridge arm switch 121, the lower bridge arm switch 124, and the lower bridge arm switch 126 are controlled on and off in a third cycle. That is, the controlled target upper bridge arm switch and the controlled lower bridge arm switch may be different in different cycles.

[0038] 1, the target conduction switches include at least one upper bridge arm switch and at least one lower bridge arm switch, and the at least one upper bridge arm switch and the at least one lower bridge arm switch are located on different bridge arms. Therefore, all upper bridge arms or all lower bridge arms cannot be simultaneously conductive in one cycle. Therefore, the current directions in the different circuits formed among the power supply module, the target upper bridge arm switch, the target lower bridge arm switch, and the motor winding are different, thereby generating an AC current.

[0039] The magnetomotive force of a single-phase winding is distributed in a stepped manner, resulting in a pulsating magnetomotive force that alters with time according to the current's change pattern. The superposition of the magnetomotive forces of three single-phase windings results in a three-phase winding composite magnetic field. Generally, the currents flowing through the three windings of a three-phase motor during the heating process are not perfectly equal in magnitude. The currents flowing through two of the windings are 180° out of phase with each other, resulting in two-phase currents with no phase difference and equal in magnitude. Because the three phases of the current flowing through the motor windings are not symmetrical and the current frequency is high, this causes the problem of loud motor vibration noise during the heating process using a power battery.

[0040] FIG. 2 shows a schematic block diagram of a charging / discharging circuit 200 provided by an embodiment of the present application.

[0041] As shown in FIG. 2, the charge / discharge circuit 200 includes a power supply module 210 , an inverter module 220 , a driving module 230 and a charge / discharge control module 240 .

[0042] The power supply module 210 is connected to the inverter module 220 and the charge / discharge control module 240 .

[0043] The inverter module 220 is connected to the power supply module 210 and the driving module 230, respectively.

[0044] The driving module 230 is connected to the inverter module 220 and the charge / discharge control module.

[0045] The charge / discharge control module 240 is connected to the power supply module.

[0046] Specifically, the power supply module includes a battery pack, which may be a collection of multiple battery modules or a battery module including multiple cells. The inverter module 220 is implemented by an inverter and includes M-phase bridge arms, where M is a positive integer greater than 0, and each phase bridge arm includes an upper bridge arm and a lower bridge arm. For example, a three-phase bridge arm includes three upper bridge arms and three lower bridge arms. The driving module 230 includes an M-phase motor, and the charge / discharge control module 240 includes a charge / discharge circuit switching bridge arm, which includes an upper bridge arm and a lower bridge arm.

[0047] In one example, the first battery pack, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm are connected in parallel, the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected in one-to-one correspondence to the M-phase windings of the M-phase motor, and the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor.

[0048] To form a charge circuit or a discharge circuit in the charge / discharge circuit 200, the upper bridge arm or the lower bridge arm of the M-phase bridge arm must be turned on, and the upper bridge arm or the lower bridge arm of the charge / discharge circuit switching bridge arm must be turned on. If the upper end of the power supply module is positive and the lower end is negative, and the upper bridge arm of the M-phase bridge arm and the lower bridge arm of the charge / discharge circuit switching bridge arm are conductive, a discharge circuit is formed. At this time, current flows out from the positive electrode of the power supply module, passes through M upper bridge arms of the M-phase bridge arm, then passes through the M-phase motor, and returns from the lower bridge arm of the charge / discharge circuit switching bridge arm to the negative electrode of the power supply module. When the lower bridge arm of the M-phase bridge arm and the upper bridge arm of the charge / discharge circuit switching bridge arm are conductive, a charge circuit is formed. At this time, current flows out from the negative electrode of the power supply module, passes through M lower bridge arms of the M-phase bridge arm, then passes through the M-phase motor, and returns from the upper bridge arm of the charge / discharge circuit switching bridge arm to the positive electrode of the power supply module.

[0049] By periodically switching between the charging and discharging circuits, a current flows inside the power supply module, thereby generating heat and heating the power supply module.

[0050] In this embodiment, the driving module 230 is not only connected to the inverter module 220, but also to the charge / discharge control module 240, so that the current flowing through the inverter module 220 can flow in from all windings of the driving module 230 and flow out from the other end of all windings at the same time, so that the current flowing through the driving module 230 can be current of the same direction and magnitude, rather than alternating current of different directions. Therefore, the problem of excessive motor vibration noise during the process of using the motor circuit to heat the power battery can be effectively reduced.

[0051] 3, 3a, 3b and 3c, the circuit diagram of the charging / discharging circuit 300 provided in the embodiment of the present application will be described in detail below.

[0052] 3, in the charge / discharge circuit 300, the power supply module includes a first battery pack 350, an M-phase bridge arm, an M-phase motor, and a charge / discharge circuit switching bridge arm 341. The first battery pack 350, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm 341 are connected in parallel, and the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected in one-to-one correspondence to the M-phase windings of the M-phase motor, and the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor.

[0053] Specifically, the M-phase bridge arm is a three-phase bridge arm and includes bridge arm 331, bridge arm 332, and bridge arm 333, and the M-phase motor is a three-phase winding motor and includes multiple windings, namely, winding 311, winding 312, and winding 313. The first battery pack 350, bridge arm 331, bridge arm 332, bridge arm 333, and bridge arm 341 are connected in parallel. The junction point between the upper bridge arm 3311 and the lower bridge arm 3312 of the bridge arm 331 is connected to one end of the winding 311, the junction point between the upper bridge arm 3321 and the lower bridge arm 3322 of the bridge arm 332 is connected to one end of the winding 312, the junction point between the upper bridge arm 3331 and the lower bridge arm 3332 of the bridge arm 333 is connected to one end of the winding 313, the other end of the winding 311, the other end of the winding 312, the other end of the winding 313 and the other end of the external inductance unit 321 are connected together, and the junction point between the upper bridge arm 3411 and the lower bridge arm 3412 of the charge / discharge circuit switching bridge arm 341 is connected to the common junction point of the windings 311, 312 and 313.

[0054] As shown in FIG. 3 , the first battery pack 350, the upper bridge arms 3311-3331, the windings 311-313, and the lower bridge arm 3412 of the charge / discharge circuit switching bridge arm 341 together form a discharge circuit, and the discharge current flows out from the positive electrode of the first battery pack 350, passes through the upper bridge arm 3321 of bridge arm 331, the upper bridge arm 3321 of bridge arm 332, and the upper bridge arm 3331 of bridge arm 333, enters the windings 311, 312, and 313, and returns to the negative electrode of the first battery pack 350 from the lower bridge arm 3412 of the charge / discharge circuit switching bridge arm 341.

[0055] Meanwhile, the first battery pack 350, the lower bridge arms 3312-3332, the windings 311-313, and the upper bridge arm 3411 of the charge / discharge circuit switching bridge arm 341 together form a charging circuit (not shown). Charging current flows out from the negative electrode of the first battery pack 350, passes through the lower bridge arm 3312 of the bridge arm 331, the lower bridge arm 3322 of the bridge arm 332, and the lower bridge arm 3332 of the bridge arm 333, enters the windings 311, 312, and 313, and returns to the positive electrode of the first battery pack 350 from the upper bridge arm 3411 of the charge / discharge circuit switching bridge arm 341.

[0056] In the embodiment shown in FIG. 3, by connecting the connection points of the motor windings and the charge / discharge circuit switching bridge arm, current can flow in from all windings simultaneously during charging or discharging, without having to pass through any one phase winding before flowing out. The currents flowing in and out of the three phase windings are always equal in magnitude with zero phase difference, so the stator magnetic field synthesized by the three-phase spatially symmetrical windings is close to zero, which effectively suppresses vibration noise generated by the interaction between the stator magnetic field and rotor magnetic field when the first motor circuit is used to heat the power battery.

[0057] In one example, at least one external inductance unit is installed between the M-phase motor and the bridge arm for switching the charging / discharging circuit, specifically, a connection point between the upper and lower bridge arms of the bridge arm for switching the charging / discharging circuit is connected to one end of the at least one external inductance unit, and the other end of the at least one external inductance unit is connected to a connection point between the M-phase winding of the M-phase motor.

[0058] 3a, in the charge / discharge circuit 300, the power supply module includes a first battery pack 350, an M-phase bridge arm, an M-phase motor, and a charge / discharge circuit switching bridge arm 341. The first battery pack 350, the M-phase bridge arm, and the charge / discharge circuit switching bridge arm 341 are connected in parallel, and the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected in one-to-one correspondence to the M-phase windings of the M-phase motor, and the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor.

[0059] Specifically, the M-phase bridge arm is a three-phase bridge arm, including bridge arm 331, bridge arm 332, and bridge arm 333, and the M-phase motor is a three-phase winding motor, including multi-phase windings, namely winding 311, winding 312, and winding 313. The first battery pack 350, bridge arm 331, bridge arm 332, bridge arm 333, and bridge arm 341 are connected in parallel. The connection point between the upper bridge arm 3311 and the lower bridge arm 3312 of the bridge arm 331 is connected to one end of the winding 311, the connection point between the upper bridge arm 3321 and the lower bridge arm 3322 of the bridge arm 332 is connected to one end of the winding 312, the connection point between the upper bridge arm 3331 and the lower bridge arm 3332 of the bridge arm 333 is connected to one end of the winding 313, the connection point between the other end of the winding 311, the other end of the winding 312, and the other end of the winding 313 is connected to the other end of the external inductance unit 321, and the connection point between the upper bridge arm 3411 and the lower bridge arm 3412 of the charge / discharge circuit switching bridge arm 341 is connected to the connection points of the windings 311, 312, and 313.

[0060] Preferably, the external inductance unit 321 may be a conductor. Also, the embodiment of the present application does not need to limit the number of external inductance units.

[0061] Preferably, the M-phase motor may be a six-phase winding motor, and accordingly, the M-phase windings may be all windings in the six-phase winding motor.

[0062] Preferably, the M-phase bridge arm may be a three-phase bridge arm or a six-phase bridge arm.

[0063] In the embodiment shown in Figure 3a, an external inductance unit is installed between the motor and the charge / discharge circuit switching bridge arm, which can increase the inductance and help reduce the current ripple during the heating process, thereby effectively increasing the charge / discharge current and improving the charge / discharge efficiency.

[0064] 3b and 3c show circuit diagrams of a charging / discharging circuit 300 provided by an embodiment of the present application.

[0065] In one example, the M-phase motor is a double motor and includes a first M-phase motor and a second M-phase motor, and an M-phase winding connection point of the first M-phase motor is connected to an M-phase winding connection point of the second M-phase motor. Specifically, the first M-phase motor and the second M-phase motor are both three-phase winding motors, and the first M-phase motor includes windings 311, 312, and 313, and the second M-phase motor includes windings 321, 322, and 323. A common connection point of windings 311, 312, and 313 is connected to a common connection point of windings 321, 322, and 323.

[0066] The connection points of the upper and lower bridge arms of the M-phase bridge arm are connected to the M-phase windings of the first M-phase motor in a one-to-one correspondence. Specifically, the M-phase bridge arms include bridge arms 331, 332, and 333. Specifically, the connection point between the upper bridge arm 3311 and the lower bridge arm 3312 of bridge arm 331 is connected to one end of the winding 311, the connection point between the upper bridge arm 3321 and the lower bridge arm 3322 of bridge arm 332 is connected to one end of the winding 312, and the connection point between the upper bridge arm 3331 and the lower bridge arm 3332 of bridge arm 333 is connected to one end of the winding 313.

[0067] The connection points of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm are connected to the M-phase windings of the second M-phase motor in a one-to-one correspondence. Specifically, the charge / discharge circuit switching bridge arm includes bridge arms 341, 342, and 343. The connection point between the upper bridge arm 3411 and the lower bridge arm 3412 of bridge arm 341 is connected to one end of winding 321, the connection point between the upper bridge arm 3421 and the lower bridge arm 3422 of bridge arm 342 is connected to one end of winding 322, the connection point between the upper bridge arm 3431 and the lower bridge arm 3432 of bridge arm 343 is connected to one end of winding 323, and the common connection point between the other end of winding 311, the other end of winding 312, the other end of winding 313, the other end of winding 321, the other end of winding 322, and the other end of winding 323 is connected.

[0068] As shown in Figure 3b, the power supply module 350, the upper bridge arms 3311, 3321, and 3331, the windings 311-313, the windings 321-323, and the lower bridge arms 3412, 3422, and 3432 together form a discharge circuit. As shown in Figure 3c, the power supply module 350, the lower bridge arms 3312, 3322, and 3332, the windings 311-313, the windings 321-323, and the upper bridge arms 3411, 3421, and 3431 together form a charge circuit. Here, the charge circuit and the discharge circuit are periodically alternately energized under the control of a control module (not shown).

[0069] 3b and 3c, by controlling the currents flowing through windings 311-313 to be equal in magnitude and in phase, the vibration noise of the first motor can be effectively suppressed during the process of heating the power battery using the motor circuit. Similarly, by controlling the currents flowing through windings 321-323 to be equal in magnitude and in phase, the vibration noise of the second motor can be effectively suppressed during the process of heating the power battery using the motor circuit.

[0070] FIG. 4 shows a schematic block diagram of a charging / discharging circuit 300 provided by an embodiment of the present application.

[0071] As shown in FIG. 4, the charge / discharge circuit 400 includes a power supply module 410, an inverter module 420, a driving module 430, and a charge / discharge control module 440.

[0072] Specifically, the power supply module 410 includes a first battery pack 4101 and a second battery pack 4102. Opening and closing a switch unit (not shown, dashed lines indicate a changeable connection) changes the connection between the first battery pack 4101 and the second battery pack 4102. Specifically, when the switch unit is turned on, the first battery pack 4101 is connected in parallel to the second battery pack 4102, and when the switch unit is turned off, the first battery pack 4101 is connected in series to the second battery pack 4102. The battery pack may be a collection of multiple battery modules or a battery module including multiple cells. The inverter module 420 can be realized by an inverter and includes M-phase bridge arms, where M is a positive integer greater than 0, and each phase bridge arm includes an upper bridge arm and a lower bridge arm. For example, a three-phase bridge arm includes three upper bridge arms and three lower bridge arms. The driving module 430 includes an M-phase motor, for example, a three-phase winding motor with three-phase windings. The charge / discharge control module 440 includes a charge / discharge circuit switching bridge arm, which includes an upper bridge arm and a lower bridge arm.

[0073] In one example, as shown in FIG. 4a, a first battery pack 4101 is connected in parallel to the M-phase bridge arm, wherein a first end of the first battery pack 4101 and an upper bridge arm of the M-phase bridge arm are collinearly connected, the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to M-phase windings of the M-phase motor in a one-to-one correspondence, and the upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor, a first end of a second battery pack 4102 is collinearly connected to the upper bridge arm of the charge / discharge circuit switching bridge arm, and a second end of the second battery pack 4102 is collinearly connected to a second end of the first battery pack 4101, the M-phase bridge arm, and the lower bridge arm of the charge / discharge circuit switching bridge arm, and a switch unit is installed between the first end of the first battery pack and the first end of the second battery pack.

[0074] Specifically, the M-phase bridge arm is a three-phase bridge arm, including bridge arm 431, bridge arm 432, and bridge arm 433, and the M-phase motor is a three-phase winding motor, including three phase windings, namely, winding 411, winding 412, and winding 413. Charging / discharging circuit switching bridge arm 421.

[0075] When the motor needs to be used to heat the power supply module, the switch unit is turned off, and the first battery pack 4101 and the second battery pack 4102 are connected in series. By controlling the upper or lower bridge arm of the M-phase bridge arm and the upper and lower bridge arms of the charge / discharge circuit switching bridge arm, charge / discharge control of the first battery packs 4101 and 4102 can be achieved. Suppose that in a first cycle, the first battery pack 4101 charges and the second battery pack 4102 discharges. At this time, the discharge current of the second battery pack 4102 flows out from its positive electrode, passes through the upper bridge arms 4311, 4321, and 4331 of the bridge arms 431-433, enters the windings 411-413, passes through the upper bridge arm 4211 of the charge circuit switching bridge arm 421, enters the positive electrode of the first battery pack 4101, flows out from the negative electrode of the first battery pack 4101, and finally returns to the negative electrode of the second battery pack 4102.

[0076] 4b, in the second cycle, the first battery pack 4101 discharges and the second battery pack 4102 charges. At this time, the discharge current of the first battery pack flows out from its positive electrode, passes through the upper bridge arm 4211 of the charging circuit switching bridge arm 421, enters the windings 411-413, passes through the upper bridge arms 4311, 4321, and 4331 of the bridge arms 431-433, enters the positive electrode of the second battery pack 4102, flows out from the negative electrode of the second battery pack 4102, and finally returns to the negative electrode of the first battery pack 4101.

[0077] In this embodiment, the dual battery pack design can effectively reduce the constraints on the heating current magnitude and heating current frequency imposed by the motor inductance, and the dual battery heating method can timely release the energy from the energy storage element to one of the batteries, thereby maintaining the battery heating current at a stable heating current magnitude according to the preset heating frequency, thereby significantly improving the heating speed by adjusting the heating current frequency when the battery is in different temperature and SOC states.

[0078] FIG. 4c shows another embodiment of the charge / discharge circuit 400, namely the circuit topology when the M motor is a double motor.

[0079] 4c, the M-phase motor is a double motor, including a first M-phase motor and a second M-phase motor, and the M-phase winding connection point of the first M-phase motor is connected to the M-phase winding connection point of the second M-phase motor. Specifically, the first M-phase motor and the second M-phase motor are both three-phase winding motors, and the first M-phase motor includes windings 411, 412, and 413, and the second M-phase motor includes windings 441, 442, and 443. The common connection point of windings 411, 412, and 413 is connected to the common connection point of windings 441, 442, and 443.

[0080] The connection points of the upper and lower bridge arms of the M-phase bridge arm are connected to the M-phase windings of the first M-phase motor in a one-to-one correspondence. Specifically, the M-phase bridge arms include bridge arms 431, 432, and 433. Specifically, the connection point between the upper bridge arm 4311 and the lower bridge arm 4312 of bridge arm 431 is connected to one end of the winding 411, the connection point between the upper bridge arm 4321 and the lower bridge arm 4322 of bridge arm 432 is connected to one end of the winding 412, and the connection point between the upper bridge arm 4331 and the lower bridge arm 4332 of bridge arm 433 is connected to one end of the winding 413.

[0081] The connection points of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm are connected to the M-phase windings of the second M-phase motor in a one-to-one correspondence. Specifically, the charge / discharge circuit switching bridge arm includes a bridge arm 421, a bridge arm 422, and a bridge arm 423. The connection point between the upper bridge arm 4211 and the lower bridge arm 4212 of the bridge arm 421 is connected to one end of the winding 441, the connection point between the upper bridge arm 4221 and the lower bridge arm 4222 is connected to one end of the winding 442, the connection point between the upper bridge arm 4231 and the lower bridge arm 4232 of the bridge arm 423 is connected to one end of the winding 443, and the common connection point between the other end of the winding 441, the other end of the winding 442, the other end of the winding 443, the other end of the winding 411, the other end of the winding 412, and the other end of the winding 413 is connected.

[0082] In the embodiment of Figure 4c, by controlling the currents flowing through windings 411-413 to be equal in magnitude and in phase, the vibration noise of the first motor can be effectively suppressed during the process of heating the power battery using the motor circuit. Similarly, by controlling the currents flowing through windings 441-443 to be equal in magnitude and in phase, the vibration noise of the second motor can be effectively suppressed during the process of heating the power battery using the motor circuit.

[0083] FIG. 5 shows a schematic block diagram of a charging / discharging system 500 provided by an embodiment of the present application.

[0084] 5, the charging / discharging system 500 includes a power supply module 510, an inverter module 520, a control module 530, a driving module 540, and a charging / discharging control module 550. The control module 530 is used to control the charging / discharging circuit configured by the power supply module 510, the inverter module 520, the driving module 540, and the charging / discharging control module 550. Here, the circuit configured by the power supply module 510, the inverter module 520, the driving module 540, and the charging / discharging control module 550 may be equivalent to the charging / discharging circuit 200 or 400 in the above embodiments.

[0085] In one example, the control module 530 is a vehicle controller or a vehicle controller. The controller may include a VCU (Vehicle Control Unit) and / or a motor controller.

[0086] In one example, the power supply module 510 is a power battery.

[0087] When the charging / discharging system 500 is used to heat the power supply module, the controller sends an enable signal to the inverter module 520 and the charging / discharging control module 550 to control the inverter module and the charging / discharging control module in the charging / discharging circuit (e.g., the charging / discharging circuit 200 or 400) to form a charging circuit or a discharging circuit.

[0088] When the charging / discharging circuit is the charging / discharging circuit 200, the upper bridge arm or the lower bridge arm of the M-phase bridge arm is made conductive in response to an enable signal sent from the controller, and the upper bridge arm or the lower bridge arm of the charging circuit switching bridge arm is made conductive, thereby forming a charging circuit or a discharging circuit. By repeatedly switching between the charging circuit or the discharging circuit, the power supply module is charged and discharged, and the heat generated when the current passes through the power supply module is used to heat it.

[0089] When the charging / discharging circuit is the charging / discharging circuit 400, in response to an enable signal sent from the controller, the upper bridge arm or the lower bridge arm of the M-phase bridge arm is made conductive, and the upper bridge arm or the lower bridge arm of the charging circuit switching bridge arm is made conductive, thereby forming a charging circuit or a discharging circuit. The charging circuit or the discharging circuit charges or discharges the first battery pack or the second battery pack, and charging / discharging includes switching the charging / discharging states of the first battery pack and the second battery pack, where charging / discharging states include charging the first battery pack and simultaneously discharging the second battery pack, or discharging the first battery pack and simultaneously charging the second battery pack.

[0090] In one example, the control module is used to determine the state of charge (SOC) of a power battery. The state of charge (SOC) is the ratio of the remaining charge to the rated capacity of a battery under the same conditions at a certain discharge rate. The SOC is one of the important parameters of a battery management system and is also the basis for the overall charge / discharge control policy and battery equalization operation of a vehicle. However, due to the complexity of the structure of lithium batteries themselves, their state of charge cannot be obtained by direct measurement. Instead, the SOC can be estimated using only certain external characteristics of the battery, such as the battery's internal resistance, temperature, current, and other related parameters, using related characteristic curves or calculation formulas.

[0091] In one example, the control module is further used to receive a heating request sent from a battery management system BMS, and the heating request is used to instruct the power battery to meet the heating requirement.

[0092] In one example, by receiving a heating request sent from a Battery Management System (BMS), the control module can heat the power battery in a timely manner to avoid affecting the use of a power device such as a vehicle.

[0093] In one example, the control module is further used to send a heating stop signal to the inverter module and the charge / discharge control module to turn off the charging circuit or the discharging circuit, thereby stopping heating to the power battery, when the temperature of the power battery reaches a predetermined temperature or the temperature rise of the power battery is abnormal.

[0094] In one example, when the vehicle controller receives a heating request sent from the BMS, the vehicle controller can send a control signal to the motor controller, and the control signal is used to instruct the power battery to heat up, i.e., the control signal is used to instruct the motor controller to send an enable signal to the inverter module and the charge / discharge control module, thereby forming a charge circuit or a discharge circuit in the charging electrical circuit.

[0095] The system of this embodiment uses a control module to control the inverter module and the charge / discharge control module, and can determine when to charge / discharge based on the vehicle's status, thereby heating the power battery to ensure battery safety, and by controlling the charge / discharge currents to be equal in magnitude and phase, the vibration noise of the motor can be effectively suppressed.

[0096] The above is a detailed description of the charging / discharging system of the embodiment of the present application, and the charging / discharging control method of the embodiment of the present application will be described in detail below with reference to Fig. 6. The technical features described in the device embodiment are also applicable to the following method embodiment.

[0097] As shown in FIG. 6, the control method includes the following steps:

[0098] S601, the BMS collects battery parameters such as the temperature, SOC, voltage signal and current signal of the battery pack.

[0099] S602: The BMS determines whether the heating conditions are met based on the battery parameters. If the heating conditions are met, it sends a corresponding heating request to the VCU based on the SOC status, for example, sending the VCU the power required to heat to a specified temperature.

[0100] In S603, the BMS or VCU determines whether the battery SOC is greater than the first threshold.

[0101] S604, if the SOC is greater than the first threshold, heat the power battery using the heat generated by the AC current flowing through the motor circuit.

[0102] S605: if the SOC is equal to or less than the first threshold, heat the power battery using the heat generated by the DC current flowing through the motor circuit;

[0103] After S604, the VCU reads the current operating state of the first motor.

[0104] For example, when the first motor is in a driving state (i.e., in an operating state), the VCU sends a driving signal to the motor controller, and the motor controller sends an enabling signal to the inverter module and the charge / discharge control module to control the conduction of the upper or lower bridge arm of the M-phase bridge arm of the inverter module and the conduction of the upper or lower bridge arm of the charge / discharge circuit switching bridge arm of the charge / discharge control module.

[0105] In one example, the motor controller periodically sends an enable signal, thereby controlling the conduction of different associated bridge arms, and further realizing the switching between the charging circuit and the discharging circuit, and realizing the inverter control of the current of the power battery.

[0106] S606: The BMS determines whether there is an abnormality in the temperature of the battery pack, and if there is an abnormality, sends temperature rise abnormality information to the VCU, and the VCU transfers the temperature rise abnormality information to the motor controller and stops heating.

[0107] If S607 and S606 determine that there is no abnormality in the temperature rise, the BMS determines whether the temperature of the battery pack reaches the required level. If the required level is reached, the VCU transfers heating stop information to the motor controller and stops heating; if not, S601 to S606 are repeated.

[0108] The present invention can be applied to situations where a low-temperature power battery needs to be heated. For example, heating the power battery can be applied to specific situations where the temperature of the power battery is increased to a temperature at which the battery pack can be normally used. Specifically, in the present invention, when the battery state of charge (SOC) is greater than a first threshold, the current flowing through the circuit can be modulated to an alternating current, and the alternating current can be used to generate heat through the internal resistance of the power battery, thereby heating the power battery and improving heating efficiency. When the battery SOC is below the first threshold, i.e., when the battery capacity is insufficient, a direct current can be used to generate heat in the windings to heat the power battery, thereby reducing battery capacity consumption and improving the flexibility of the power battery heating system.

[0109] 7 shows a schematic block diagram of a control circuit 700 of the charging / discharging system according to the present embodiment. As shown in FIG. 7, the control circuit 700 includes a processor 710, and preferably, the control circuit 700 further includes a memory 720, where the memory 720 is used to store instructions, and the processor 710 is used to read the instructions and perform the methods of the various embodiments of the present application described above based on the instructions.

[0110] Those skilled in the art can understand that the units and algorithm steps of each example described with reference to the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals can implement the described functions using different methods for each specific application, but such implementation should not be considered to go beyond the scope of the present application.

[0111] Those skilled in the art will clearly understand that for convenience and brevity of explanation, the specific operating processes of the above-described systems, devices, and units may refer to the corresponding processes in the above-described method embodiments, and the description thereof will be omitted here.

[0112] In some embodiments provided herein, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative, and the division of the units is merely a division of logical functions. In actual implementation, other division methods may be used. For example, multiple units or components may be combined or integrated into other systems, or some features may be omitted or not implemented. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections between some interfaces, devices, or units, and may be electrical, mechanical, or other types of interfaces.

[0113] The units described as separate components may or may not be physically separated, and the component that is the display unit may or may not be a physical unit, i.e., it may be located in one place or distributed among multiple network units, and some or all of the units can be selected according to actual needs to achieve the objective of the solution of this embodiment.

[0114] Furthermore, each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist physically alone, or two or more units may be integrated into one unit.

[0115] When the functions are realized in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on this understanding, the essence of the technical solution of the present application or a part that contributes to the prior art or a part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium and includes some instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program code, such as a USB memory, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0116] The foregoing is merely a specific embodiment of the present application, and the scope of protection of the present application is not limited thereto. Any modifications or substitutions that a person skilled in the art can easily conceive within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be determined based on the scope of protection of the following claims.

Claims

1. A charge / discharge circuit, a power supply module including at least a first battery pack and a second battery pack; an inverter module including M-phase bridge arms, where M is a positive integer greater than 0; a charge / discharge control module including a charge / discharge circuit switching bridge arm; a drive module including an M-phase motor; and a switch unit; wherein the first battery pack and the M-phase bridge arm are connected in parallel, and a first end of the first battery pack and an upper bridge arm of the M-phase bridge arm are connected in a collinear manner; upper and lower bridge arm connection points of the M-phase bridge arm are connected to M-phase windings of the M-phase motor in one-to-one correspondence, a connection point of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm is connected to the M-phase motor; a first end of the second battery pack is connected to the upper bridge arm of the charge / discharge circuit switching bridge arm in a common line; a second end of the second battery pack is connected to the second end of the first battery pack, the M-phase bridge arm, and the lower bridge arm of the charge / discharge circuit switching bridge arm in a common line; The switch unit is disposed between a first end of the first battery pack and a first end of the second battery pack. A charge / discharge circuit comprising:

2. At least one external inductance unit is installed between the M-phase motor and the charging / discharging circuit switching bridge arm.

2. The charge / discharge circuit according to claim 1.

3. The connection point of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm is connected to the M-phase motor, The upper and lower bridge arm connection points of the charging / discharging circuit switching bridge arm are connected to one end of the at least one external inductance unit, and the other end of the at least one external inductance unit is connected to an M-phase winding connection point of the M-phase motor.

3. The charge / discharge circuit according to claim 2.

4. When the switch unit is turned on, the first battery pack is connected in parallel to the second battery pack, and when the switch unit is turned off, the first battery pack is connected in series to the second battery pack.

2. The charge / discharge circuit according to claim 1.

5. The M-phase motor is a double motor, including a first M-phase motor and a second M-phase motor, wherein an M-phase winding connection point of the first M-phase motor is connected to an M-phase winding connection point of the second M-phase motor.

2. The charge / discharge circuit according to claim 1.

6. The upper and lower bridge arm connection points of the M-phase bridge arm are connected to the M-phase windings of the M-phase motor in one-to-one correspondence, The upper and lower bridge arm connection points of the M-phase bridge arm are connected to the M-phase windings of the first M-phase motor in one-to-one correspondence.

6. The charge / discharge circuit according to claim 5.

7. The connection point of the upper and lower bridge arms of the charge / discharge circuit switching bridge arm is connected to the M-phase motor, The upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase windings of the second M-phase motor in one-to-one correspondence, respectively.

6. The charge / discharge circuit according to claim 5.

8. A charging and discharging system, The system includes a control module and a charge / discharge circuit according to any one of claims 1 to 7, The control module is used to send commands to the charging / discharging circuit to control the charging / discharging of the power supply module. A charging and discharging system characterized by the above.

9. A charge / discharge control method applied to an electrical system, comprising: the electrical system includes a control module and a charge / discharge circuit; the charging / discharging circuit includes a power supply module, an inverter module, a charging / discharging control module, a driving module, and a switch unit, wherein the power supply module includes at least a first battery pack and a second battery pack, the inverter module includes an M-phase bridge arm, where M is a positive integer greater than 0, the charging / discharging control module includes a charging / discharging circuit switching bridge arm, and the driving module includes an M-phase motor; the first battery pack and the M-phase bridge arm are connected in parallel, a first end of the first battery pack and an upper bridge arm of the M-phase bridge arm are connected in a collinear manner, upper and lower bridge arm connection points of the M-phase bridge arm are connected to M-phase windings of the M-phase motor in a one-to-one correspondence, upper and lower bridge arm connection points of the charge / discharge circuit switching bridge arm are connected to the M-phase motor, a first end of the second battery pack is connected in a collinear manner with the upper bridge arm of the charge / discharge circuit switching bridge arm, and a second end of the second battery pack is connected in a collinear manner with a second end of the first battery pack, the M-phase bridge arm, and the lower bridge arm of the charge / discharge circuit switching bridge arm, and the switch unit is installed between the first end of the first battery pack and the first end of the second battery pack, The method comprises: in response to an enable signal transmitted from the control module, an upper bridge arm or a lower bridge arm of the M-phase bridge arm is made conductive, and an upper bridge arm or a lower bridge arm of the charge / discharge circuit switching bridge arm is made conductive, thereby forming a charge circuit or a discharge circuit, and charging or discharging the first battery pack or the second battery pack through the charge circuit or the discharge circuit; The charging and discharging includes switching the charging and discharging states of the first battery pack and the second battery pack, and the charging and discharging states include charging the first battery pack and discharging the second battery pack at the same time, or discharging the first battery pack and charging the second battery pack at the same time. A charge / discharge control method comprising:

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