Charge and discharge circuit, system and its control method

Abstract

The embodiment of the present application provides a charge-discharge circuit, system, and control method thereof, including: a power supply module including at least a first 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; and a drive module including 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; the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected one-to-one with the 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. 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 generated by the uneven stator magnetic field of the motor under heating conditions.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a charging and discharging circuit, system, and control method thereof. Background Art

[0002] Due to its advantages such as high energy density, rechargeable, safe and environmentally friendly, power batteries are widely used in new energy vehicles, consumer electronics, energy storage systems and other fields.

[0003] However, the use of power batteries in low-temperature environments is subject to certain limitations. Specifically, the discharge capacity of power batteries will decline significantly in low-temperature environments, and the batteries cannot be charged in low-temperature environments. Therefore, in order to ensure normal use of power batteries in low-temperature environments, they need to be heated.

[0004] Traditional power battery heating technology may cause excessive motor vibration and noise when using the motor circuit to heat the power battery. Summary of the Invention

[0005] The embodiments of the present application provide a charging and discharging circuit, system, and control method thereof, which can effectively suppress the vibration noise of the motor when the motor circuit is used to heat the battery.

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

[0007] The upper and lower bridge arm connection points of the bridge arm are switched through the charge and discharge circuit and connected to the M-phase motor, thereby allowing the current flowing through the M-phase motor to have the same magnitude and phase, thereby avoiding the noise generated by the uneven stator magnetic field under heating conditions.

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

[0009] By providing a charging and discharging circuit switching bridge arm, the output current flow direction of the M-phase motor can be switched, thereby controlling the charging and discharging process of the power supply unit. This allows the charging current to be increased when the M-phase motor circuit is used to heat the power supply module, thereby improving charging efficiency. Furthermore, by connecting the upper and lower bridge arm connection points of the charging and discharging circuit switching bridge arm to the M-phase motor, the M-phase motor can generate zero-sequence current, thereby preventing rotor heating caused by an uneven magnetic field during motor operation, which in turn leads to motor demagnetization.

[0010] In a possible implementation, at least one external inductor unit is provided between the M-phase motor and the charging and discharging circuit switching bridge arm.

[0011] In one possible implementation, the connection point of the upper and lower bridge arms of the charge and 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] By setting up external energy storage elements, the impedance of energy storage elements such as motor windings can be effectively increased, so that the charging and discharging current of the power supply module can be stably maintained at a large level, thereby effectively improving the charging and discharging efficiency of the power supply module and increasing the battery heating rate.

[0013] In one possible implementation, the M-phase motor is a dual motor, including a first M-phase motor and a second M-phase motor; wherein 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.

[0014] In a possible implementation, 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 a one-to-one correspondence.

[0015] In a possible implementation, 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 a one-to-one correspondence.

[0016] By connecting the winding connection points of the dual motors and controlling the conduction switching of the motor controller at the same time, the current flowing into and out of the motor is controlled to always remain in the same direction, so that the synthetic magnetic field generated by the windings of the motor during the heating process is minimized, which can effectively reduce the vibration noise and rotor heating problems of the motor.

[0017] In a third aspect, a charging and discharging system is provided, which includes a control module and the above-mentioned charging and discharging circuit; the control module is used to send instructions to the charging and discharging circuit to control the power supply module to charge and discharge.

[0018] In a fourth aspect, a charge and discharge control method is provided, which is applied to an electric power system, which includes: a control module and a charge and discharge circuit; the charge and discharge circuit includes: a power supply module, an inverter module, a charge and 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, M is a positive integer greater than 0; the charge and discharge control module includes a charge and 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 and 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 one-to-one with the M-phase winding of the M-phase motor; the upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor; the method includes: in response to the enable signal sent by the controller, the upper bridge arm of the M-phase bridge arm is turned on or the lower bridge arm is turned on, and the upper bridge arm of the charge and discharge circuit switching bridge arm is turned on or the lower bridge arm is turned on, so that a charging circuit or a discharging circuit is formed; repeatedly switching the charging circuit or the discharging circuit to charge and discharge the power supply module.

[0019] In a fifth aspect, a charge and discharge control method is provided, which is applied to an electric power system, wherein the electric power system includes: a control module and a charge and discharge circuit; the charge and discharge circuit includes: a power supply module, an inverter module, a charge and 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 and discharge control module includes a charge and 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, wherein the first end of the first battery pack and the 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 one-to-one with the M-phase winding of the M-phase motor; the upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor; the first end of the second battery pack is connected to the charge and discharge The upper bridge arm of the electrical circuit switching bridge arm is connected in a collinear manner; the second end of the second battery group is connected in a collinear manner with the second end of the first battery group, the M-phase bridge arm, and the lower bridge arm of the charge and discharge circuit switching bridge arm; the switch unit is arranged between the first end of the first battery group and the first end of the second battery group; the method includes: in response to an enable signal sent by the controller, the upper bridge arm of the M-phase bridge arm is turned on or the lower bridge arm is turned on, and the upper bridge arm or the lower bridge arm of the charge and discharge circuit switching bridge arm is turned on, so that a charging circuit and a discharging circuit are formed; the first battery group and the second battery group are charged and discharged through the charging circuit and the discharging circuit; charging and discharging include switching the charging and discharging states of the first battery group and the second battery group; wherein the charging and discharging states include the first battery group charging while the second battery group discharging, or the first battery group discharging while the second battery group charging.

[0020] By controlling the upper and lower arms of the M-phase bridge arm through the control module, the phase and magnitude of the winding current of the M-phase motor can be made the same, thereby avoiding noise generated by the uneven magnetic field during motor operation and causing rotor heating, which in turn leads to motor demagnetization. In addition, the dual-battery setting can effectively reduce the constraints of motor inductance on the heating current magnitude and heating current frequency. Through the dual-battery heating method, the energy of the energy storage element can be promptly discharged to one of the batteries, so that the battery heating current can be maintained at a stable heating current magnitude according to the preset heating frequency. By adjusting the heating current frequency, the heating rate can be greatly improved under different battery temperatures and SOC states. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0022] Figure 1It is a circuit diagram of a traditional charging and discharging circuit.

[0023] Figure 2 This is a schematic block diagram of a discharge circuit provided in one embodiment of the present application.

[0024] Figure 3 is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0025] Figure 3a is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0026] Figure 3b is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0027] Figure 3c is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0028] Figure 4 is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0029] Figure 4a is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0030] Figure 4b is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0031] Figure 4c is a circuit diagram of a charge and discharge circuit provided in one embodiment of the present application.

[0032] Figure 5 This is a schematic block diagram of a charging and discharging system provided in one embodiment of the present application.

[0033] Figure 6 This is a flow chart of a control method for a power battery heating scenario provided by an embodiment of the present application.

[0034] Figure 7 This is a schematic block diagram of a charge and discharge control device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0035] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0036] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0037] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0038] With the development of the times, new energy vehicles have huge market prospects due to their environmental friendliness, low noise, low cost of use and other advantages. They can effectively promote energy conservation and emission reduction, which is beneficial to the development and progress of society.

[0039] Due to the electrochemical characteristics of power batteries, their charge and discharge capabilities are greatly limited in low-temperature environments, seriously affecting customers' winter driving experience. Therefore, in order to ensure normal use of power batteries in low-temperature environments, they need to be heated.

[0040] The power battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cathode battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., which are not limited here. In terms of scale, the battery in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which are not limited here. In terms of application scenarios, the battery can be used in power devices such as automobiles and ships. For example, it can be used in power cars to power the motor of the power car and serve as a power source for the electric car. The battery can also power other electrical devices in the electric car, such as the air conditioner in the car, the car player, etc.

[0041] For ease of description, the following will be explained using the application of a power battery in a new energy vehicle (power vehicle) as an example.

[0042] The drive motor and its control system are core components of new energy vehicles. Their driving characteristics determine the vehicle's primary performance indicators. The motor drive system in new energy vehicles primarily consists of an electric motor (i.e., motor), a motor controller (e.g., inverter), various detection sensors, and a power supply. The motor is a rotating electromagnetic machine that operates on the principle of electromagnetic induction, converting electrical energy into mechanical energy. During operation, it absorbs electrical power from the electrical system and outputs mechanical power to the mechanical system.

[0043] In order to avoid unnecessary cost when heating the power battery, the power battery can be heated by using a motor circuit.

[0044] Figure 1 Figure 1 shows a charging and discharging circuit diagram of a traditional power battery heating system. Figure 1 As shown, the power battery heating system 100 may include a power supply module 110 , an inverter module 120 connected to the power supply module 110 , and a drive module 130 connected to the inverter module 120 .

[0045] The power supply module 110 can be implemented not only with a power battery itself but also with an external power supply module such as a charging station. The heating energy provided by the external power supply module can be, for example, the output of an external DC charger or the output of an external AC charger after rectification, without specific limitation here.

[0046] For the inverter module 120, various types of switches can be used for implementation. For example, the inverter module 120 can be implemented by an inverter in a motor drive system, wherein the inverter can be implemented by a bridge arm switch of an insulated gate bipolar transistor (IGBT). 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 a three-phase bridge arm, that is, a U-phase bridge arm, a V-phase bridge arm and a W-phase bridge arm. Among them, each phase bridge arm in the three-phase bridge arm has an upper bridge arm and a lower bridge arm, and its upper bridge arm and lower bridge arm are each provided with a switch unit, 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.

[0047] The driver module 130 may specifically 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 winding 131 is connected to the connection point between the upper and lower bridge arms of the U-phase bridge arm, one end of 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 winding 133 is connected to the connection point between the upper and lower bridge arms of the W-phase bridge arm. The other ends of winding 131, winding 132, and winding 133 are collinearly connected.

[0048] It should be noted that the driving module 130 is not limited to a three-phase winding motor, but may also 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.

[0049] In some embodiments, current can be modulated by periodically controlling the on / off switching of switches in the inverter module 120. For example, current can be modulated by periodically controlling the on / off switching of the target upper-arm switch and the target lower-arm switch in the inverter module 120. In one example, if the target upper-arm switch is the upper-arm switch 121, the target lower-arm switch is the lower-arm switch 124 and / or the lower-arm switch 126. In another example, if the target upper-arm switch is the upper-arm switch 123, the target lower-arm switch is the lower-arm switch 122 and / or the lower-arm switch 126. In another example, if the target upper-arm switch is the upper-arm switch 125, the target lower-arm switch is 122 and / or the lower-arm switch 124. In another example, if the target upper-arm switch is the upper-arm switch 121 and / or the upper-arm switch 123, the target lower-arm switch is 126. In another example, if the target upper arm switch is upper arm switch 123 and / or upper arm switch 125, the target lower arm switch is lower arm switch 122. In another example, if the target upper arm switch is upper arm switch 121 and / or upper arm switch 125, the target lower arm switch is 124.

[0050] It should be noted that the target upper bridge arm switch and target lower bridge arm switch for periodically turning on and off in each cycle can be the same or different, and this is not limited here. For example, the upper bridge arm switch 121 and the lower bridge arm switch 124 are controlled to be turned on and off in each cycle. For another example, in the first cycle, the upper bridge arm switch 121 and the lower bridge arm switch 124 are controlled to be turned on and off; in the second cycle, the upper bridge arm switch 123 and the lower bridge arm switch 122 are controlled to be turned on and off; in the third cycle, the upper bridge arm switch 121, the lower arm switch 124, and the lower bridge arm switch 126 are controlled to be turned on and off. That is, in different cycles, the target upper bridge arm switch and the lower arm switch to be controlled can be different.

[0051] It can be seen that the use of Figure 1In the charge and discharge circuit shown, the target conduction switch includes 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, it is impossible to simultaneously conduct all upper bridge arms or lower bridge arms in one cycle, so the current directions in different loops formed between 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 alternating current.

[0052] Since the magnetomotive force of the unidirectional winding is distributed in a step-like manner in space, it is a pulsating magnetomotive force that alternates over time according to the law of current change. The superposition of the magnetomotive forces of the three single-phase windings is the synthetic magnetic field of the three-phase winding. Usually, the currents flowing into the three-phase windings of the three-phase winding motor during the heating process are not completely equal in magnitude. The currents flowing through two of the phase windings are 180° out of phase with each other, and the two-phase currents without phase difference are equal in magnitude. This will cause the three phases of current flowing through the motor winding to be asymmetrical with each other, and the high current frequency will cause the motor vibration and noise to be large during the heating process of the power battery.

[0053] Figure 2 A schematic block diagram of a charge-discharge circuit 200 provided in an embodiment of the present application is shown.

[0054] like Figure 2 As shown, the charge and discharge circuit 200 includes: a power supply module 210 , an inverter module 220 , a drive module 230 and a charge and discharge loop control module 240 .

[0055] The power supply module 210 is connected to the inverter module 220 and the charge-discharge circuit control module 240 .

[0056] The inverter module 220 is connected to the power supply module 210 and the drive module 230 respectively.

[0057] The driving module 230 is connected to the inverter module 220 and the charge-discharge circuit control module respectively.

[0058] The charge and discharge control module 240 is connected to the power supply module.

[0059] Specifically, the power supply module includes a battery pack, which can be a collection of multiple battery modules or a battery module comprising multiple cells. The inverter module 220 is implemented as an inverter and includes M-phase bridge arms, where M is a positive integer greater than 0. 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 drive module 230 includes an M-phase motor. The charge-discharge control module 240 includes a charge-discharge circuit switching bridge arm, including an upper bridge arm and a lower bridge arm.

[0060] In one example, the first battery pack, the M-phase bridge arm and the charge and 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 one-to-one with the M-phase winding of the M-phase motor; the upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor.

[0061] In order to form a charging loop or a discharging loop in the charge-discharge circuit 200, it is necessary to turn on the upper bridge arm or the lower bridge arm of the M-phase bridge arm, and to turn on the upper bridge arm or the lower bridge arm of the charge-discharge loop switching bridge arm. Assuming that the upper end of the power supply module is the positive pole and the lower end is the negative pole, when the upper bridge arm of the M-phase bridge arm and the lower bridge arm of the charge-discharge loop switching bridge arm are turned on, a discharging loop is formed. At this time, the current flows out from the positive pole of the power supply module, passes through the M upper bridge arms of the M-phase bridge arm, and then passes through the M-phase motor, and returns from the lower bridge arm of the charge-discharge loop switching bridge arm to the negative pole 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 loop switching bridge arm are turned on, a charging loop is formed. At this time, the current flows out from the negative pole of the power supply module, passes through the M lower bridge arms of the M-phase bridge arm, and then passes through the M-phase motor, and returns from the upper bridge arm of the charge-discharge loop switching bridge arm to the positive pole of the power supply module.

[0062] By periodically switching the charging circuit and the discharging circuit, current flows inside the power supply module, thereby generating heat to heat the power supply module.

[0063] In this embodiment, the driver module 230 is connected not only to the inverter module 220 but also to the charge-discharge control module 240. This allows the current flowing through the inverter module 220 to simultaneously flow into all windings of the driver module 230 and out of the other end of all windings. This ensures that the current flowing through the driver module 230 is of the same direction and magnitude, rather than alternating currents with different directions. This effectively reduces the problem of excessive motor vibration and noise during the process of using the motor circuit to heat the power battery.

[0064] The following combination Figure 3 、 3a , 3b and 3c, describe in detail the circuit diagram of the charging circuit 300 provided in an embodiment of the present application.

[0065] like Figure 3 As shown, in the charging 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; the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the 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.

[0066] Specifically, the M-phase bridge arm is a three-phase bridge arm, including bridge arm 331, bridge arm 332, and bridge arm 333. The M-phase motor is a three-phase winding motor, including 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 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 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 inductor 321 are connected together, and the connection point between the upper bridge arm 3411 and the lower bridge arm 3412 of the charge and discharge circuit switching bridge arm 341 is connected to the common connection point of the windings 311, 312 and 313.

[0067] like Figure 3 As shown, the first battery group 350, the upper bridge arms 3311 to 3331, the windings 311 to 313, and the lower bridge arm 3412 of the charge-discharge circuit switching bridge arm 341 together form a discharge circuit; the discharge current flows out from the positive pole of the first battery group 350, passes through the upper bridge arm 3321 of the bridge arm 331, the upper bridge arm 3321 of the bridge arm 332, and the upper bridge arm 3331 of the bridge arm 333, enters the windings 311, 312, and 313, and returns to the negative pole of the first battery group 350 through the lower bridge arm 3412 of the charge-discharge circuit switching bridge arm 341.

[0068] On the other hand, 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 collectively form a charging circuit (not shown). The charging current flows from the negative electrode of the first battery pack 350, passes through the lower bridge arm 3312 of bridge arm 331, the lower bridge arm 3322 of bridge arm 332, and the lower bridge arm 3332 of bridge arm 333, enters the windings 311, 312, and 313, and returns to the positive electrode of the first battery pack 350 through the upper bridge arm 3411 of the charge-discharge circuit switching bridge arm 341.

[0069] exist Figure 3 In the embodiment shown, by connecting the connection points of the motor windings with the connection points of the charging and discharging circuit switching bridge arms, current is allowed to flow into all windings simultaneously during charging or discharging without having to flow out through any phase winding. Since the current flowing into or out of the three-phase windings is always equal in magnitude and the phase difference is zero, the stator magnetic field composed of the three-phase spatially symmetrical windings is close to zero, thereby effectively suppressing the vibration noise generated by the interaction between the stator magnetic field and the rotor magnetic field when the first motor circuit is used to heat the power battery.

[0070] In one example, at least one external inductor unit is provided between the M-phase motor and the charge-discharge circuit switching bridge arm. Specifically, the connection point between the upper and lower bridge arms of the charge-discharge circuit switching bridge arm is connected to one end of the at least one external inductor unit, and the other end of the at least one external inductor unit is connected to the connection point of the M-phase winding of the M-phase motor.

[0071] like Figure 3a As shown, 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; the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the 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.

[0072] Specifically, the M-phase bridge arm is a three-phase bridge arm, including bridge arm 331, bridge arm 332, and bridge arm 333. The M-phase motor is a three-phase winding motor, including 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 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 other end of the winding 311, the other end of the winding 312, and the connection point of the other end of the winding 313 are connected to the other end of the external inductor unit 321, and the connection point between the upper bridge arm 3411 and the lower bridge arm 3412 of the charge and discharge circuit switching bridge arm 341 is connected to the connection points of the windings 311, 312, and 313.

[0073] Optionally, the external inductor unit 321 may be a wire. In addition, the embodiment of the present application may not limit the number of external inductor units.

[0074] Optionally, the M-phase motor may also be a six-phase winding motor, and accordingly, the M-phase winding may be all the windings in the six-phase winding motor.

[0075] Optionally, the M-phase bridge arm may be a three-phase bridge arm or a six-phase bridge arm.

[0076] In the embodiment shown in 3a, by setting an external inductance unit between the motor and the charging and discharging circuit switching bridge arm, the inductance can be increased, which is beneficial to reducing the current ripple during the heating process, thereby effectively increasing the charging and discharging current and improving the charging and discharging efficiency.

[0077] Figure 3b and Figure 3c FIG. 4 shows a circuit diagram of a charge-discharge circuit 300 provided in an embodiment of the present application.

[0078] In one example, the M-phase motor is a dual motor, including a first M-phase motor and a second M-phase motor; 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, with the first M-phase motor including winding 311, winding 312, and winding 313; and the second M-phase motor including winding 321, winding 322, and winding 323. The common connection point of windings 311, 312, and 313 is connected to the common connection point of windings 321, 322, and 323.

[0079] The upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the M-phase winding of the first M-phase motor in a one-to-one correspondence. Specifically, the M-phase bridge arm includes bridge arm 331, bridge arm 332, and bridge arm 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 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 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 winding 313.

[0080] The upper and lower bridge arm connection points of the charge-discharge circuit switching bridge arm are respectively connected to the M-phase winding of the second M-phase motor in a one-to-one correspondence. Specifically, the charge-discharge circuit switching bridge arm includes bridge arm 341, bridge arm 342, and bridge arm 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, and 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. 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 are connected to a common connection point.

[0081] like Figure 3b As shown, the power supply module 350, the upper bridge arms 3311, 3321, 3331, the windings 311-313, the windings 321-323 and the lower bridge arms 3412, 3422, 3432 together form a discharge circuit. Figure 3c As shown, the power supply module 350, the lower bridge arms 3312, 3322, 3332, the windings 311-313, the windings 321-323, and the upper bridge arms 3411, 3421, 3431 together form a charging circuit. Under the control of a control module (not shown), the charging circuit and the discharging circuit are periodically and alternately turned on.

[0082] exist Figure 3b and Figure 3c In the illustrated embodiment, by controlling the currents flowing into windings 311-313 to be equal in magnitude and 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 out of windings 321-323 to be equal in magnitude and 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] Figure 4 A schematic block diagram of a charge-discharge circuit 300 provided in an embodiment of the present application is shown.

[0084] like Figure 4 As shown, the charge and discharge circuit 400 includes: a power supply module 410 , an inverter module 420 , a drive module 430 and a charge and discharge loop control module 440 .

[0085] Specifically, the power supply module 410 includes a first battery pack 4101 and a second battery pack 4102. The opening and closing of a switch unit (not shown in the figure; the dotted line indicates a variable connection relationship) changes the connection relationship between the first battery pack 4101 and the second battery pack 4102. Specifically, when the switch unit is closed, the first battery pack 4101 and the second battery pack 4102 are connected in parallel; when the switch unit is disconnected, the first battery pack 4101 and the second battery pack 4102 are connected in series. A battery pack can be a collection of multiple battery modules or a battery module comprising multiple cells. The inverter module 420 can be implemented as an inverter and includes M-phase bridge arms, where M is a positive integer greater than 0. 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 drive module 430 includes an M-phase motor; for example, the M-phase motor is a three-phase winding motor with three phase windings. The charge and discharge control module 440 includes a charge and discharge circuit switching bridge arm, including an upper bridge arm and a lower bridge arm.

[0086] In one example, if Figure 4a As shown, the first battery group 4101 is connected in parallel with the M-phase bridge arm, wherein the first end of the first battery group 4101 and the upper bridge arm of the M-phase bridge arm are connected in a collinear manner; the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected one-to-one with the M-phase winding of the M-phase motor; the upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor; the first end of the second battery group 4102 is connected in a collinear manner with the upper bridge arm of the charge and discharge circuit switching bridge arm; the second end of the second battery group 4102 is connected in a collinear manner with the second end of the first battery group 4101, the M-phase bridge arm, and the lower bridge arm of the charge and discharge circuit switching bridge arm; the switch unit is arranged between the first end of the first battery group and the first end of the second battery group.

[0087] Specifically, the M-phase bridge arm is a three-phase bridge arm, including bridge arm 431, bridge arm 432, and bridge arm 433; the M-phase motor is a three-phase winding motor, including three-phase windings, namely winding 411, winding 412, and winding 413. The charging and discharging circuit switches the bridge arm 421.

[0088] When the motor is needed to heat the power supply module, the switch unit is disconnected, and the first battery pack 4101 and the second battery pack 4102 are now connected in series. By controlling the upper or lower bridge arm of the M-phase bridge arm, as well as the upper and lower bridge arms of the charge-discharge circuit switching bridge arm, the charge and discharge of the first battery pack 4101 and 4102 can be controlled. Assume that in the first cycle, the first battery pack 4101 is charging and the second battery pack 4102 is discharging. At this time, the discharge current of the second battery pack 4102 flows 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 charging 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.

[0089] like Figure 4b As shown, 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, and then enters the upper bridge arms 4311, 4321, and 4331 of the bridge arms 431-433 into 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.

[0090] In this embodiment, the design of the dual battery pack can effectively reduce the constraints of the motor inductance on the heating current size and the heating current frequency. Through the dual battery heating method, the energy of the energy storage element can be discharged to one of the batteries in time, so that the heating current of the battery can be maintained at a stable heating current size according to the preset heating frequency. By adjusting the heating current frequency under different temperatures and SOC states, the heating rate can be greatly improved.

[0091] Figure 4c Another embodiment of the charge and discharge circuit 400 is shown, that is, the circuit topology when the M motor is a dual motor.

[0092] Specifically, if Figure 4cAs shown, the M-phase motor is a dual motor, including a first M-phase motor and a second M-phase motor; 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. The first M-phase motor includes winding 411, winding 412, and winding 413; the second M-phase motor includes winding 441, winding 442, and winding 443. The common connection point of windings 411, 412, and 413 is connected to the common connection point of windings 441, 442, and 443.

[0093] The upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the M-phase winding of the first M-phase motor in a one-to-one correspondence. Specifically, the M-phase bridge arm includes bridge arm 431, bridge arm 432, and bridge arm 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 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 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 winding 413.

[0094] The upper and lower bridge arm connection points of the charge-discharge circuit switching bridge arm are respectively connected to the M-phase winding of the second M-phase motor in a one-to-one correspondence. Specifically, the charge-discharge circuit switching bridge arm includes bridge arm 421, bridge arm 422, and bridge arm 423. The connection point between the upper bridge arm 4211 and the lower bridge arm 4212 of bridge arm 421 is connected to one end of winding 441, the connection point between the upper bridge arm 4221 and the lower bridge arm 4222 of bridge arm 422 is connected to one end of winding 442, the connection point between the upper bridge arm 4231 and the lower bridge arm 4232 of bridge arm 423 is connected to one end of winding 443, and the other end of winding 441, the other end of winding 442, the other end of winding 443, the other end of winding 411, the other end of winding 412, and the other end of winding 413 are connected to a common connection point.

[0095] exist Figure 4c In the embodiment, by controlling the currents flowing into windings 411-413 to be equal in magnitude and 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 out of windings 4411-443 to be equal in magnitude and phase, the vibration noise of the second motor can be effectively suppressed during the process of heating the power battery using the motor circuit.

[0096] Figure 5 A schematic block diagram of a charging and discharging system 500 provided in an embodiment of the present application is shown.

[0097] like Figure 5As shown, the charge-discharge system 500 includes a power supply module 510, an inverter module 520, a control module 530, a drive module 540, and a charge-discharge control module 550. The control module 530 is used to control the charge-discharge circuit composed of the power supply module 510, the inverter module 520, the drive module 540, and the charge-discharge control module 550. The circuit composed of the power supply module 510, the inverter module 520, the drive module 540, and the charge-discharge control module 550 can be equivalent to the charge-discharge circuit 200 or 400 in the above-mentioned embodiment.

[0098] In one example, the control module 530 may include a vehicle control unit (VCU) and / or a motor controller.

[0099] In one example, the power supply module 510 is a power battery.

[0100] When the charging and discharging system 500 is used to heat the power supply module, the controller sends an enable signal to the inverter module 520 and the charge and discharge control module 550 to control the inverter module and the charge and discharge control module in the charge and discharge circuit (for example, the charge and discharge circuit 200 or 400) to form a charging circuit or a discharging circuit.

[0101] When the charge and discharge circuit is the charge and discharge circuit 200, in response to the enable signal sent by the controller, the upper bridge arm of its M-phase bridge arm is turned on or the lower bridge arm is turned on, and the upper bridge arm or the lower bridge arm of the charge and discharge circuit switching bridge arm is turned on, so that a charging circuit or a discharging circuit is formed; the charging circuit or the discharging circuit is repeatedly switched to charge and discharge the power supply module, thereby utilizing the heat generated when the current passes through the inside of the power supply module to heat it.

[0102] When the charge and discharge circuit is the charge and discharge circuit 400, then in response to the enable signal sent by the controller, the upper bridge arm of the M-phase bridge arm is turned on or the lower bridge arm is turned on, and the upper bridge arm or the lower bridge arm of the charge and discharge circuit switching bridge arm is turned on, so that a charging circuit or a discharging circuit is formed; the first battery group or the second battery group is charged and discharged through the charging circuit or the discharging circuit, and the charging and discharging includes switching the charging and discharging states of the first battery group and the second battery group; wherein the charging and discharging states include the first battery group charging while the second battery group discharging; or the first battery group discharging while the second battery group charging.

[0103] In one example, the control module is used to determine the power battery's state of charge (SOC). State of charge (SOC) refers to the ratio of a battery's remaining capacity at a certain discharge rate to its rated capacity under the same conditions. SOC is a key parameter in the battery management system and serves as the basis for the vehicle's charge and discharge control strategies and battery balancing. However, due to the structural complexity of lithium-ion batteries, their state of charge cannot be directly measured. SOC can only be estimated based on certain external battery characteristics, such as internal resistance, temperature, current, and other related parameters, using relevant characteristic curves or calculation formulas.

[0104] In one example, the control module is further used to: receive a heating request sent by a battery management system BMS, where the heating request is used to indicate that the power battery meets a heating condition.

[0105] In one example, by receiving a heating request sent by a battery management system (BMS), the control module can heat the power battery in a timely manner to avoid affecting the use of power devices such as vehicles.

[0106] In one example, the control module is also used to: when the temperature of the power battery reaches a preset temperature or the temperature rise of the power battery is abnormal, send a heating stop signal to the inverter module and the charge and discharge control module, disconnect the charging circuit or the discharge circuit, and thus stop heating the power battery.

[0107] In one example, when the vehicle controller receives a heating request sent by the BMS, the vehicle controller can send a control signal to the motor controller. The control signal is used to instruct the heating of the power battery, that is, the control signal is used to instruct the motor controller to send an enable signal to the inverter module and the charge and discharge control module, so that a charging loop or a discharge loop is formed in the charging circuit.

[0108] The system of this embodiment controls the inverter module and the charge and discharge control module through the control module, and can decide when to charge and discharge according to the status of the vehicle to ensure that the battery can heat the power battery; and by controlling the charge and discharge currents to be equal in magnitude and the same in phase, the vibration noise of the motor can be effectively suppressed.

[0109] The above describes the charging and discharging system of the embodiment of the present application in detail. Figure 6 The charge and discharge control method of the embodiment of the present application is described in detail. The technical features described in the device embodiment are applicable to the following method embodiment.

[0110] like Figure 6 As shown, the control method includes:

[0111] In step S601, the BMS collects battery parameters such as the battery pack's temperature, SOC, voltage signal, and current signal.

[0112] S602, the BMS determines whether the heating conditions are met based on various battery parameters. If so, the BMS sends a corresponding heating request to the VCU based on the SOC state, for example, sending the required electric power for heating to a preset temperature to the VCU.

[0113] S603: The BMS or VCU determines whether the battery SOC is greater than a first threshold.

[0114] S604: If the SOC is greater than the first threshold, heat generated by the AC current flowing through the motor circuit is used to heat the power battery.

[0115] S605 : If the SOC is less than or equal to the first threshold, heat generated by the direct current flowing through the motor circuit is used to heat the power battery.

[0116] After 604 , the VCU reads the current working status of the first motor.

[0117] For example, if the first motor is in the driving state (i.e., working state), the VCU sends a driving signal to the motor controller. At this time, the motor controller sends an enable signal to the inverter module and the charge-discharge control module to control the upper or lower bridge arm of the M-phase bridge arm of the inverter module to be turned on, and the upper or lower bridge arm of the charge-discharge circuit switching bridge arm of the charge-discharge control module to be turned on.

[0118] In one example, the motor controller periodically sends an enable signal to control the conduction of different related bridge arms, thereby realizing the switching of the charging circuit and the discharging circuit, and realizing the inversion control of the power battery current.

[0119] S606, the BMS determines whether the battery pack temperature is abnormal. If so, it sends a temperature rise abnormality message to the VCU. The VCU forwards the temperature rise abnormality message to the motor controller and stops heating.

[0120] S607: If S606 determines that the temperature rise is normal, the BMS determines whether the battery pack temperature meets the requirements. If so, the VCU forwards the stop heating information to the motor controller to stop heating; otherwise, repeat S601 to S606.

[0121] The embodiment of the present application can be applied to the scenario of heating a power battery with a relatively low temperature. For example, it can be applied to a specific scenario in which the temperature of the power battery is raised by heating the power battery to a temperature at which the battery pack can be used normally. Specifically, in the embodiment of the present application, when the state of charge (SOC) of the battery is greater than a first threshold, the current flowing through the loop can be modulated into an AC current, and the AC current is used to generate heat through the internal resistance of the power battery, thereby heating the power battery, which can improve the heating efficiency; when the battery SOC is less than or equal to the first threshold, that is, when the battery power is insufficient, the DC current is used to generate heat in the winding to heat the power battery, which can reduce power consumption and improve the flexibility of the power battery heating system.

[0122] Figure 7 FIG. 7 is a schematic block diagram of a control circuit 700 of a charge and discharge system according to an embodiment of the present application. Figure 7 As shown, the control circuit 700 includes a processor 710. Optionally, the control circuit 700 also includes a memory s20, wherein the memory 720 is used to store instructions, and the processor 710 is used to read the instructions and execute the methods of the various embodiments of the present application based on the instructions.

[0123] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented 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. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0124] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0125] In the several embodiments provided in this application, 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 schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0126] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0127] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0128] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0129] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art 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 based on the scope of protection of the claims.

Claims

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

2. The charge and discharge circuit according to claim 1, wherein: include: At least one external inductance unit is provided between the M-phase motor and the charging and discharging circuit switching bridge arm.

3. The charge and discharge circuit according to claim 2, wherein: The upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor, including: The upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to one end of the at least one external inductor unit, and the other end of the at least one external inductor unit is connected to the M-phase winding connection point of the M-phase motor.

4. The charge and discharge circuit according to claim 1, wherein: The M-phase motor is a dual motor, including a first M-phase motor and a second M-phase motor; wherein 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.

5. The charge and discharge circuit according to claim 4, characterized in that: The upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected to the M-phase winding of the M-phase motor in a one-to-one correspondence, including: 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 a one-to-one correspondence.

6. The charge and discharge circuit according to claim 4, characterized in that: The upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are connected to the M-phase motor, including: The upper and lower bridge arm connection points of the charge and discharge circuit switching bridge arm are respectively connected to the M-phase windings of the second M-phase motor in a one-to-one correspondence.

7. A charging and discharging system, characterized in that: The system includes a control module and the charge-discharge circuit according to any one of claims 1 to 6; the control module is used to send instructions to the charge-discharge circuit to control the power supply module to charge and discharge.

8. A charge and discharge control method, applied to an electric power system, the electric power system comprising: Control module and charging and discharging circuit; The charge and discharge circuit comprises: A power supply module, an inverter module, a charge and 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 M-phase bridge arms, where M is a positive integer greater than 0; the charge and discharge control module includes a charge and discharge circuit switching bridge arm; and the drive module includes an M-phase motor; The first battery pack and the M-phase bridge arm are connected in parallel, wherein the first end of the first battery pack and the 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 one-to-one with the M-phase winding of 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 motor; the first end of the second battery pack is collinearly connected to the upper bridge arm of the charge-discharge circuit switching bridge arm; the 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; the switch unit is arranged between the first end of the first battery and the first end of the second battery pack; The method comprises: In response to the enable signal sent by the control module, the upper bridge arm of the M-phase bridge arm is turned on or the lower bridge arm is turned on, and the upper bridge arm of the charging and discharging circuit switching bridge arm is turned on or the lower bridge arm is turned on, so that a charging circuit or a discharging circuit is formed; the first battery group or the second battery group is charged and discharged through the charging circuit or the discharging circuit, and the charging and discharging includes switching the charging and discharging states of the first battery group and the second battery group; wherein, the charging and discharging states include the first battery group charging while the second battery group discharging; or the first battery group discharging while the second battery group charging.

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