Charging and discharging system and control method, electronic device, electrical energy device, and medium

Abstract

A charging and discharging system and a control method, an electronic device, an electrical energy device, and a medium. The electrical energy device comprises a charging and discharging system and an electronic device. The charging and discharging system comprises a motor drive circuit, a motor, and a plurality of control switches. The motor drive circuit comprises multi-phase bridge arms in parallel connection, each phase of bridge arm is connected to two ends of a positive electrode and a negative electrode of a battery, and a first end of each phase of bridge arm is connected to a first end of a charging and discharging port. The motor comprises a plurality of groups of windings, each group of windings comprises at least one set of windings, each set of windings comprises multi-phase windings, first ends of the multi-phase windings are correspondingly connected to midpoints of multi-phase bridge arms, second ends of the multi-phase windings in each set of windings are connected as neutral poles, neutral poles of each group of windings are connected together, a wire harness is led out from neutral poles of the plurality of groups of windings, and the led out wire harness is connected to at least one of a second end of the charging and discharging port and a positive terminal of the battery. A plurality of control switches are arranged on the led out wire harness, and are used for, on the basis of a target charging and discharging mode and a target charging and discharging current, controlling a corresponding quantity of windings to form a charging and discharging loop.

Description

Charging and discharging system, control method, electronic device, electric energy device, and medium

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202411376283.X, filed on September 27, 2024, and entitled “Charging and discharging system, control method, electronic device, electric energy device, and medium”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of vehicles, and in particular to a charging and discharging system, a control method, an electronic device, an electric energy device, and a medium. BACKGROUND

[0004] In the prior art, for a vehicle-to-home (VTOH) charging device, the voltage range of the direct current charging and discharging port is 150V to 450V, and the maximum charging and discharging power is within 10kW. When testing the charging function of the VTOH device, even if the device is not connected to a load, the instrument will still display a certain charging and discharging power. This part of the power is the self-loss of the device, and a large loss of the device under the charging and discharging working condition will cause the charging and discharging efficiency of the battery to decrease, and this condition will be obviously reflected in the case that the efficiency is poor at small power direct current charging and discharging.

[0005] SUMMARY

[0006] The present disclosure aims to at least solve one of the technical problems existing in the prior art. To this end, a first object of the present disclosure is to provide a charging and discharging system. When the battery needs to be charged and discharged at a small power, the number of windings participating in work can be reduced by controlling the conduction of a corresponding number of windings, the inductance can be increased, the ripple can be reduced, and thus the loss can be reduced, so as to improve the efficiency of small power direct current charging and discharging.

[0007] A second object of the present disclosure is to provide a charging and discharging system.

[0008] A third object of the present disclosure is to provide a charging and discharging control method.

[0009] A fourth object of the present disclosure is to provide an electronic device.

[0010] A fifth object of the present disclosure is to provide an electric energy device.

[0011] A sixth object of the present disclosure is to provide a non-transitory readable storage medium.

[0012] To achieve the above object, the charging and discharging system according to an embodiment of the present disclosure comprises: a motor driving circuit, the motor driving circuit comprising bridge arms connected in parallel, each bridge arm being connected across the positive and negative poles of a battery, and a first end of each bridge arm being connected to a first end of a charging and discharging port; a motor, the motor comprising groups of windings, each group of windings comprising at least one set of windings, each set of windings comprising multiple-phase windings, a first end of each set of windings being connected to a midpoint of a multiple-phase bridge arm, and a second end of each set of windings being connected to a neutral pole, the neutral poles of each group of windings being connected together, and a neutral pole lead bundle of the groups of windings being connected to at least one of a second end of the charging and discharging port and a positive pole of the battery; and a plurality of control switches, the plurality of control switches being arranged on the neutral pole lead bundle and being used to switch according to a target charging and discharging mode and a target charging and discharging current, so as to control a corresponding number of windings to form a charging and discharging loop.

[0013] According to the charging and discharging system provided by the embodiment of the present disclosure, the neutral pole lead bundle of the groups of windings of the motor is led out, and the neutral pole lead bundle is connected to at least one of the second end of the charging and discharging port and the positive pole of the battery, a plurality of control switches are arranged on the neutral pole lead bundle, and the switching states of the plurality of control switches are controlled according to the target charging and discharging mode and the target charging and discharging current, so as to control a corresponding number of windings to form a corresponding charging and discharging loop. That is, by means of the switching states of the plurality of control switches, a smaller number of windings can be controlled to be turned on as much as possible under the requirements of different target charging and discharging modes and target charging and discharging currents, so as to reduce the number of windings participating in work, thereby increasing the inductance and reducing the ripple, so as to reduce the loss, meet the requirements of the charging and discharging loop on the inductance and overcurrent capacity, meet the requirements of the phase current ripple and the efficiency of the charging and discharging system, and effectively improve the efficiency of the charging and discharging of the battery, especially for small-power charging and discharging working conditions.

[0014] In some embodiments of the present disclosure, the groups of windings comprise different numbers of sets of windings, and the neutral poles of each group of windings are connected to the second end of the charging and discharging port through the control switches.

[0015] In some embodiments of the present disclosure, the neutral poles of at least one group of windings are also connected to the positive pole of the battery.

[0016] In some embodiments of the present disclosure, the motor comprises a first group of windings and a second group of windings, and the first group of windings comprises a smaller number of sets of windings than the second group of windings.

[0017] In some embodiments of the present disclosure, the plurality of control switches comprises a first switch and a second switch, the first switch is arranged between the neutral pole of the first group of windings and the second end of the charge-discharge port, and the second switch is arranged between the neutral pole of the second group of windings and the second end of the charge-discharge port.

[0018] In some embodiments of the present disclosure, in the boost charge-discharge mode, when the first group of windings meets the target charge-discharge current, the first switch is closed and the second switch is opened; in the boost charge-discharge mode, when the first group of windings does not meet the target charge-discharge current and the second group of windings meets the target charge-discharge current, the first switch is opened and the second switch is closed; in the boost charge-discharge mode, when the second group of windings does not meet the target charge-discharge current, both the first switch and the second switch are controlled to be closed.

[0019] In some embodiments of the present disclosure, the neutral pole of the first group of windings is connected to the positive terminal of the battery.

[0020] In some embodiments of the present disclosure, the plurality of control switches comprises a third switch, the third switch is arranged between the neutral pole of the first group of windings and the positive terminal of the battery, and is used for being closed in the boost current charge-discharge mode.

[0021] In some embodiments of the present disclosure, the neutral pole of the first group of windings is also connected to the neutral pole of the second group of windings; the plurality of control switches further comprises a fourth switch, the fourth switch is arranged on the connection line between the neutral pole of the first group of windings and the neutral pole of the second group of windings, and is used for being closed when the first group of windings cannot meet the target charge-discharge current in the boost current charge-discharge mode.

[0022] In some embodiments of the present disclosure, the first group of windings comprises one set of windings, and the second group of windings comprises three sets of windings.

[0023] In some embodiments of the present disclosure, the neutral pole of at least one group of windings in the plurality of groups of windings is connected to the second end of the charge-discharge port through the control switch, and the neutral pole of the windings other than the windings connected to the second end of the charge-discharge port in the plurality of groups of windings is connected to the positive terminal of the battery through the control switch.

[0024] In some embodiments of the present disclosure, in the boost charge-discharge mode, the control switch arranged on the connection line between the neutral pole and the second end of the charge-discharge port is closed, or in the boost current charge-discharge mode, the control switch arranged on the connection line between the neutral pole and the positive terminal of the battery is closed.

[0025] In some embodiments of the present disclosure, the multiple groups of windings include different numbers of winding sets.

[0026] In some embodiments of the present disclosure, the multiple groups of windings include the same number of winding sets.

[0027] In some embodiments of the present disclosure, the motor includes a third group of windings and a fourth group of windings, the third group of windings includes the same number of winding sets as the fourth group of windings; a neutral pole of the third group of windings is connected to a second end of the charge-discharge port, and a neutral pole of the fourth group of windings is connected to a positive terminal of the battery.

[0028] In some embodiments of the present disclosure, the multiple control switches include a fifth switch disposed on a connection line between the neutral pole of the third group of windings and the second end of the charge-discharge port, and configured to be closed in the boost charge-discharge mode; and a sixth switch disposed on a connection line between the neutral pole of the fourth group of windings and the positive terminal of the battery, and configured to be closed in the boost charge-discharge mode.

[0029] In some embodiments of the present disclosure, the neutral pole of the third group of windings is connected to the neutral pole of the fourth group of windings; and the multiple control switches further include a seventh switch disposed on a connection line between the neutral pole of the third group of windings and the neutral pole of the fourth group of windings, and configured to be closed when the third group of windings does not meet the target charge-discharge current in the boost charge-discharge mode, or configured to be closed when the fourth group of windings does not meet the target charge-discharge current in the boost charge-discharge mode.

[0030] In some embodiments of the present disclosure, the third group of windings includes two winding sets, and the fourth group of windings includes two winding sets.

[0031] In some embodiments of the present disclosure, the second end of each phase bridge arm is further connected to the second end of the charge-discharge port; and the charge-discharge system further includes an eighth switch disposed on a connection line between the second end of the bridge arm and the second end of the charge-discharge port, and configured to be closed in the direct connection charge-discharge mode or the boost charge-discharge mode.

[0032] In some embodiments of the present disclosure, the charge-discharge system further includes a positive main contactor disposed on a connection line between the second end of each phase bridge arm and the positive terminal of the battery, and configured to be closed in the direct connection charge-discharge mode or the boost charge-discharge mode; and a negative main contactor disposed on a connection line between the first end of each phase bridge arm and the negative terminal of the battery, and configured to be closed in the direct connection charge-discharge mode or the boost charge-discharge mode.

[0033] In some embodiments of the present disclosure, the charge-discharge system further comprises a ninth switch, which is arranged on a connection line between the first end of the charge-discharge port and the first end of each phase bridge arm, and is used to be closed in the direct connection charge-discharge mode or the step-up charge-discharge mode or the step-up current charge mode.

[0034] In some embodiments of the present disclosure, the charge-discharge system further comprises a pre-charge unit, which is closed during charge-discharge.

[0035] To achieve the above object, the second aspect of the present disclosure further provides a charge-discharge system, comprising: a motor drive circuit, the motor drive circuit comprising a plurality of parallelly connected phase bridge arms, each phase bridge arm being connected across the positive and negative electrodes of a battery, and a first end of each phase bridge arm being further connected to a first end of a charge-discharge port; a motor, the motor comprising a plurality of groups of windings, each group of windings comprising at least one set of windings, and each set of windings comprising a plurality of phase windings, a first end of each phase winding in each set of windings being connected to a midpoint of a plurality of phase bridge arms, and a second end of each phase winding in each set of windings being connected together, a wire harness being led between the first end of at least one phase winding in the plurality of phase windings and the midpoint of the plurality of phase bridge arms, and the led wire harness being connected to at least one of a second end of the charge-discharge port and a positive electrode end of the battery; and a plurality of control switches, the plurality of control switches being arranged on the led wire harness, and being used to be switched according to a target charge-discharge mode and a target charge-discharge current, so as to form a corresponding charge-discharge loop.

[0036] According to the charge-discharge system provided by the embodiments of the present disclosure, the neutral point of each group of windings of the motor is not led out, but a wire harness is led between the first end of at least one phase winding in the plurality of phase windings and the midpoint of the plurality of phase bridge arms, and the led wire harness is connected to at least one of the second end of the charge-discharge port and the positive electrode end of the battery, and a plurality of control switches are arranged on the led wire harness, and the switching state of the plurality of control switches is controlled according to the target charge-discharge mode, so as to form a charge-discharge loop, that is, the requirements of different target charge-discharge modes can be met by the switching state of the plurality of control switches, so as to realize a plurality of charge-discharge functions.

[0037] To achieve the above object, the third aspect of the present disclosure provides a charge-discharge control method, which is used for the charge-discharge system described in any one of the above embodiments, and the charge-discharge control method comprises: acquiring a target charge-discharge current; and controlling the switching state of a plurality of control switches arranged on a led wire harness of a neutral point of each group of windings in the charge-discharge system according to the target charge-discharge current and a target charge-discharge mode, so as to control a corresponding number of windings to form a charge-discharge loop.

[0038] According to the charging and discharging control method provided in the embodiments of the present disclosure, the hardware structure and the control algorithm of the charging and discharging system are combined through the charging and discharging system for any one of the above, and through the switching state of the multiple control switches, the number of windings that are turned on can be controlled as small as possible under the requirements of different target charging and discharging modes and target charging and discharging currents, so as to reduce the number of windings that work, thereby increasing the inductance and reducing the ripple, so as to reduce the loss, meet the requirements of the inductance and overcurrent capacity of the charging and discharging circuit, and meet the requirements of the phase current ripple and the efficiency of the charging and discharging system. Especially for the small-power charging and discharging working condition, the efficiency of the battery charging and discharging can be effectively improved.

[0039] In some embodiments of the present disclosure, the charging and discharging control method further comprises: controlling the switching state of the multi-phase bridge arm of the charging and discharging system according to the target charging and discharging current and the rotor position of the motor.

[0040] In some embodiments of the present disclosure, the control of the switching state of the multi-phase bridge arm of the charging and discharging system according to the target charging and discharging current and the rotor position of the motor comprises: determining the number of winding phases required to form the charging and discharging circuit according to the target charging and discharging current; determining the target phase winding corresponding to the number of winding phases according to the rotor position of the motor, and controlling the switching state of the target phase winding corresponding to the target phase bridge arm.

[0041] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, which is a single-phase winding in the multi-phase winding that has the smallest torque when the generated magnetic field and the magnetic field generated by the rotor are combined, or when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is a winding that has the smallest torque when the generated superimposed magnetic field and the magnetic field generated by the rotor are combined.

[0042] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, which is a single-phase winding in the multi-phase winding that has the smallest angle between the direction of the generated magnetic field and the direction of the magnetic field generated by the rotor, or when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is a winding that has the smallest angle between the direction of the generated superimposed magnetic field and the direction of the magnetic field generated by the rotor.

[0043] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, which is a single-phase winding in the multi-phase winding that has the smallest angle between the direction of the generated magnetic field and the direction of the magnetic field generated by the rotor, or when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is a winding that has the smallest angle between the direction of the generated superimposed magnetic field and the direction of the magnetic field generated by the rotor.

[0044] In some embodiments of the present disclosure, when the target phase winding is a multiphase winding, the multiphase winding is controlled in uniform phase difference or in the same phase.

[0045] In some embodiments of the present disclosure, the charge-discharge control method further comprises: when the actual charge-discharge current and the target charge-discharge current are increasingly smaller in current difference, controlling the carrier frequency of the corresponding bridge arm to have an increasing trend, or when the voltage difference between the charge-discharge port and the battery is increasingly smaller, controlling the carrier frequency of the corresponding bridge arm to have a decreasing trend.

[0046] In some embodiments of the present disclosure, the target charge-discharge current is the minimum current value among a first charge-discharge current, a second charge-discharge current and a third charge-discharge current; the first charge-discharge current is obtained according to the motor winding temperature, the motor rotor temperature and the power device temperature; the second charge-discharge current is obtained according to the battery System on Chip (SOC), the minimum battery voltage, the current battery voltage, the maximum battery voltage and the battery temperature; and the third charge-discharge current is obtained according to the current voltage platform of the charging pile, the charge-discharge state of the charging gun and the charge-discharge power of the charging gun.

[0047] To achieve the above object, the fourth aspect of the present disclosure further provides an electronic device, comprising: at least one processor; a memory in communication connection with the at least one processor; the memory stores a computer program which can be executed by the at least one processor, and the at least one processor executes the computer program to implement the charge-discharge control method of any one of the above.

[0048] The electronic device provided by the embodiments of the present disclosure, when the computer program stored in the memory is executed by the at least one processor, implements the charge-discharge control method of any one of the above, can control as few windings as possible to be turned on under the requirements of different target charge-discharge modes and target charge-discharge currents, thereby increasing inductance and reducing ripple, reducing loss, meeting the requirements of inductance and overcurrent capacity of the charge-discharge circuit and meeting the requirements of phase current ripple and the requirements of charge-discharge system efficiency, and especially for small-power charge-discharge working conditions, the efficiency of battery charge-discharge can be effectively improved.

[0049] To achieve the above object, the fifth aspect of the present disclosure further provides an electric energy device, comprising a battery, a charge-discharge port, an electronic device of claim 33 and a charge-discharge system of any one of the above, the charge-discharge system is connected with the battery and the charge-discharge port, and the electronic device is connected with the charge-discharge system.

[0050] The electric energy device provided by the embodiment of the present disclosure, based on the architecture of the battery, the charging and discharging port, the electronic device and the charging and discharging system, can meet the requirements of the inductance and overcurrent capacity of the charging and discharging loop, the requirements of the phase current ripple and the efficiency of the charging and discharging system during the charging and discharging process of the battery, especially in the small power charging and discharging working condition of the electric energy device, can effectively improve the charging and discharging efficiency of the battery, so as to reduce the overall loss of the electric energy device and improve the working efficiency of the electric energy device.

[0051] In order to achieve the above-mentioned purpose, the sixth aspect of the present disclosure also provides a non-temporary computer readable storage medium, which stores a computer program, and the computer program is executed to realize the charging and discharging control method of any one of the above.

[0052] The non-temporary computer readable storage medium provided by the embodiment of the present disclosure can realize the charging and discharging control method of any one of the above, can control as few windings as possible under the requirements of different target charging and discharging modes and target charging and discharging currents, can increase inductance, reduce ripple, reduce loss, meet the requirements of the inductance and overcurrent capacity of the charging and discharging loop, meet the requirements of the phase current ripple and the efficiency of the charging and discharging system, and especially for the small power charging and discharging working condition, can effectively improve the charging and discharging efficiency of the battery.

[0053] Additional aspects and advantages of the present disclosure will be in part apparent and in part pointed out hereinafter in the description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0054] The above and / or additional aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0055] Fig. 1 is a schematic diagram of a charging and discharging system according to one embodiment of the present disclosure;

[0056] Fig. 2 is a schematic diagram of current flow in a boost charging and discharging mode according to one embodiment of the present disclosure;

[0057] Fig. 3 is a schematic diagram of current flow in a boost charging and discharging mode according to another embodiment of the present disclosure;

[0058] Fig. 4 is a schematic diagram of current flow in a boost charging and discharging mode according to yet another embodiment of the present disclosure;

[0059] Fig. 5 is a schematic diagram of current flow in a boost charging and discharging mode according to yet another embodiment of the present disclosure;

[0060] Fig. 6 is a schematic diagram of a charging and discharging system according to another embodiment of the present disclosure;

[0061] FIG. 7 is a schematic diagram of a charge-discharge system according to yet another embodiment of the present disclosure;

[0062] FIG. 8 is a schematic diagram of a charge-discharge system according to yet another embodiment of the present disclosure;

[0063] FIG. 9 is a schematic diagram of a charge-discharge system according to yet another embodiment of the present disclosure;

[0064] FIG. 10 is a schematic diagram of a charge-discharge system according to yet another embodiment of the present disclosure;

[0065] FIG. 11 is a flowchart of a charge-discharge control method according to an embodiment of the present disclosure;

[0066] FIG. 12 is a flowchart of a charge-discharge control method according to another embodiment of the present disclosure;

[0067] FIG. 13 is a schematic diagram of selecting a region of a single-phase winding based on a minimum torque principle according to an embodiment of the present disclosure;

[0068] FIG. 14 is a schematic diagram of selecting a region of a single-phase winding based on a minimum angle between stator and rotor magnetic fields principle according to an embodiment of the present disclosure;

[0069] FIG. 15 is a schematic diagram of selecting a region of a single-phase winding based on a maximum inductance of a charge-discharge loop winding principle according to an embodiment of the present disclosure;

[0070] FIG. 16 is a flowchart of a charge-discharge control method according to yet another embodiment of the present disclosure;

[0071] FIG. 17 is a block diagram of an electronic device according to an embodiment of the present disclosure;

[0072] FIG. 18 is a block diagram of an electric energy device according to an embodiment of the present disclosure.

[0073] Reference signs: electric energy device 100; charge-discharge system 10; battery 20; charge-discharge port 30; electronic device 40; pre-charging unit 50; processor 401; memory 402; motor drive circuit 1; motor 2; control switch K; positive main contactor K+; negative main contactor K-; first switch K1; second switch K2; third switch K3; fourth switch K4; fifth switch K5; sixth switch K6; eighth switch K8; ninth switch K9; tenth switch K10; eleventh switch K11; twelfth switch K12; thirteenth switch K13; pre-charging switch K0; pre-charging resistor R; bus capacitor C1; charge-discharge port capacitor C2; first power device VT1; second power device VT2; third power device VT3; fourth power device VT4; fifth power device VT5; sixth power device VT6. DETAILED DESCRIPTION

[0074] In the related art, for the VTOH device, the voltage range of the direct current charging and discharging port is 150V to 450V, the maximum charging and discharging power is within 10kW, the direct current charging and discharging port voltage is 420V, the maximum charging and discharging power is 10kW, and the maximum charging and discharging current is 24A. When testing the charging function of the VTOH device, it is found that the charging output power is negative power when the vehicle is in the ON gear and the air conditioner is on, which is caused by low charging efficiency. In addition, the charging power is also relatively low when the vehicle is in the OFF gear, which is also caused by low charging efficiency. In addition, when testing the discharging function of the VTOH, it is found that even if the device is not connected to a load, the instrument will still display a discharging power of 2.8kW, which is too large. This part of the discharging loss is also caused by low charging and discharging efficiency. The message data and the vehicle test find that the assembly loss is large under the VTOH step-up charging and discharging working condition, and the loss is about 2kW. Therefore, it can be seen that the step-up charging and discharging module of the charging and discharging system has large inherent loss, and the efficiency is poor when the small power direct current charging and discharging.

[0075] Based on this, an embodiment of the present disclosure proposes a charging and discharging system 10. When the battery 20 needs to be charged and discharged at a small power, the number of windings participating in work can be reduced by controlling the conduction of the corresponding number of windings, thereby increasing the inductance, reducing the ripple, and further reducing the loss, so as to improve the efficiency of small power direct current charging and discharging.

[0076] The embodiments of the present disclosure will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary.

[0077] The charging and discharging system 10 according to an embodiment of the present disclosure will be described below with reference to FIGS. 1-9. FIG. 1 is a schematic diagram of the charging and discharging system 10 according to an embodiment of the present disclosure, wherein the charging and discharging system 10 includes a motor drive circuit 1, a motor 2, and a plurality of control switches K.

[0078] The motor drive circuit 1 includes a plurality of phase-parallel connected bridge arms, each phase bridge arm is connected between the positive and negative electrodes of the battery 20, and the first end of each phase bridge arm is further connected to the first end of the charging and discharging port 30.

[0079] The motor 2 includes a plurality of groups of windings, each group of windings includes at least one set of windings, each set of windings includes a plurality of phase windings, the first end of the plurality of phase windings in each set of windings is connected to the midpoint of the plurality of phase bridge arms, the second end of the plurality of phase windings in each set of windings is connected to a neutral point, the neutral points of each group of windings are connected together, the neutral points of the plurality of groups of windings are led out as a wire harness, and the wire harness is connected to at least one of the second end of the charging and discharging port 30 and the positive electrode of the battery 20.

[0080] It can be understood that the motor 2 includes a permanent magnet synchronous motor, an electrically excited motor, a hybrid excitation motor, and an asynchronous motor, etc., wherein the number of motor phases can be three-phase, five-phase, six-phase, nine-phase, and twelve-phase, etc., which is not specifically limited here, and the number of inverter bridge arms used in the motor drive circuit 1 can be configured according to the number of phases of the motor 1. And the neutral point of the motor 2 is led out, the neutral point of the motor 2 can be led out in multiple numbers, the number of poles of the motor 2 is represented by P, and the neutral point of the motor 2 is represented by n. The number of neutral points n is the greatest common divisor of the number of poles P. The number of neutral points n of the motor 2 depends on the parallel structure of the winding inside the motor 2. Wherein the motor 2 can include multiple sets of winding forms, wherein the motor 2 coil can be set to include x sets of windings, x ≥ 1 and x is an integer.

[0081] It can be understood that for the VTOH device, in the small power charging and discharging working condition, the charging and discharging electric energy loss is mainly in the motor and the electric control power device. Among them, the motor loss mainly includes copper loss and iron loss, which is related to current amplitude, current ripple and current frequency, and the electric control power device loss mainly includes switching loss and conduction loss, which is related to current amplitude, bus voltage and switching frequency. For example, when the charging and discharging power of the VTOH device is 0-10kW, the charging and discharging current amplitude is small, the bus voltage changes little, the motor copper loss is small, the electric control power device conduction loss is small, and the motor iron loss and power device switching loss are large. Therefore, the embodiments of the present disclosure can comprehensively consider the current ripple, current frequency and switching frequency, and optimize.

[0082] Hereinafter, the motor 2 includes three-phase bridge arms and four sets of windings, and each set of windings includes three-phase windings, which are taken as an example for description, the number of neutral points n is 4, wherein the three-phase windings in the first set of windings are A1 phase, B1 phase and C1 phase respectively; the three-phase windings in the second set of windings are A2 phase, B2 phase and C2 phase respectively; the three-phase windings in the third set of windings are A3 phase, B3 phase and C3 phase respectively; the three-phase windings in the fourth set of windings are A4 phase, B4 phase and C4 phase respectively. And the neutral points n led out by each set of windings are n1, n2, n3 and n4 respectively. The first phase bridge arm includes the first power device VT1 and the second power device VT2, the second phase bridge arm includes the third power device VT3 and the fourth power device VT4, and the third phase bridge arm includes the fifth power device VT5 and the sixth power device VT6. Among them, the midpoint of the first phase bridge arm is A, the midpoint of the second phase bridge arm is B, and the midpoint of the third phase bridge arm is C. The midpoint of the first phase bridge arm A is used to control the conduction of A1 phase, A2 phase, A3 phase and A4 phase respectively; the midpoint of the second phase bridge arm B is used to control the conduction of B1 phase, B2 phase, B3 phase and B4 phase respectively; and the midpoint of the third phase bridge arm C is used to control the conduction of C1 phase, C2 phase, C3 phase and C4 phase respectively.

[0083] Multiple control switches are set on the lead-out wire harness to control the corresponding number of windings to form a charging and discharging circuit according to the target charging and discharging mode and the target charging and discharging current.

[0084] The target charging and discharging modes in this embodiment include boost charging and discharging mode, boost charging and discharging mode, and direct charging and discharging mode. The circuit shown in Figure 1 can only implement boost charging and discharging mode; the other two modes can be understood in conjunction with the following embodiments and figures.

[0085] By using motor 2 to connect different numbers of neutral points n in parallel, the equivalent phase inductance of the motor varies, resulting in different current-carrying capacities on the N line. It can be understood that the more neutral points connected in parallel within the same winding, the stronger the current-carrying capacity on the N line, the smaller the inductance, and the larger the ripple on the inductor. By selecting an appropriate number of neutral points n to connect in parallel based on the charging / discharging power and inductance requirements, and by combining the lead-in method and control algorithm according to the target charging / discharging mode and target charging / discharging current, the charging / discharging circuit's requirements for inductance and overcurrent capacity, as well as the requirements for phase current ripple and charging / discharging system efficiency, can be met.

[0086] Taking the circuit shown in Figure 1 as an example, the windings of motor 2 are led out in two parts. The first winding has one neutral pole led out separately and connected to the charging / discharging port 30 through the first switch K1. The second winding has three neutral poles connected in parallel and led out, and connected to the charging / discharging port 30 through the second switch K2.

[0087] When performing low-current boost charging and discharging operations on battery 2, the first switch K1 is closed. The winding connected to the first switch K1 has a small number of parallel neutral poles, resulting in weak current carrying capacity on the N line and high inductance. By using at least one phase winding of motor 2 for charging and discharging, the inductance is increased, ripple is reduced, and losses are decreased, thereby improving the efficiency of low-power DC charging and discharging. Furthermore, when performing low-current charging and discharging on battery 20, the system's charging and discharging efficiency can be further improved by controlling the carrier frequency of each bridge arm in the motor drive circuit. For example, a relatively high carrier frequency can be used for control under low-current charging and discharging conditions, while a relatively low carrier frequency can be used under high-current charging and discharging conditions. Simultaneously shutting down the oil pump, water pump, and fan maximizes the efficiency of low-power charging.

[0088] Or, when the battery 20 is subjected to a large-current boost charging and discharging operation, the second switch K2 is controlled to be closed, or the first switch K1 and the second switch K2 are controlled to be closed at the same time, the number of poles of the second switch K2 or the first switch K1 and the second switch K2 in parallel is large, the current carrying capacity on the N line is strong, and the inductance is weak. In the state of large-current charging and discharging, on the basis of meeting the target charging and discharging current, a relatively low carrier frequency can be used for control to improve the charging efficiency of large power.

[0089] In addition, for the VTOH device, in the small power charging and discharging working condition, since the charging and discharging current is relatively small, the optimization of the electric drive system loss and heat dissipation can be satisfied, so that the circuits such as the oil pump, the water pump and the fan can be closed at the same time in the small power charging and discharging working condition to further improve the charging and discharging efficiency.

[0090] According to the charging and discharging system 10 provided by the embodiments of the present disclosure, the neutral pole lead wire bundle of the multiple groups of windings of the motor 2 is led out, and the led-out wire bundle is connected with at least one of the second end of the charging and discharging port 30 and the positive electrode end of the battery 20, a plurality of control switches K are arranged on the led-out wire bundle, and the switching state of the plurality of control switches K is controlled according to the target charging and discharging mode and the target charging and discharging current, so as to control the corresponding number of windings to form a corresponding charging and discharging circuit. That is to say, by means of the switching state of the plurality of control switches K, the number of windings that are turned on can be controlled as small as possible under the requirement of meeting different target charging and discharging modes and target charging and discharging currents, so as to reduce the number of windings that participate in work, and then the inductance can be increased and the ripple can be reduced, so as to reduce the loss, meet the requirement of the charging and discharging circuit on the inductance and the overcurrent capacity, meet the requirement of the phase current ripple and the efficiency requirement of the charging and discharging system, and especially for the small power charging and discharging working condition, the charging and discharging efficiency of the battery 20 can be effectively improved.

[0091] In some embodiments of the present disclosure, the multiple groups of windings include different numbers of winding sets, and the neutral poles of each group of windings are connected with the second end of the charging and discharging port 30 through the control switch K.

[0092] In some embodiments of the present disclosure, the motor 2 includes a first group of windings and a second group of windings, and the number of winding sets included in the first group of windings is less than the number of winding sets included in the second group of windings. In some embodiments, the motor 2 shown in FIG. 1 includes four groups of windings, for example, the first group of windings includes one winding set, and the second group of windings includes three winding sets.

[0093] In some embodiments of the present disclosure, as shown in FIG. 1, the charge-discharge system 10 comprises a positive main contactor K+ and a negative main contactor K-, the positive main contactor K+ is arranged on the connection line between the second end of each phase bridge arm and the positive terminal of the battery 20, and is used to be closed in the direct connection charge-discharge mode or the step-up charge-discharge mode; the negative main contactor K- is arranged on the connection line between the first end of each phase bridge arm and the negative terminal of the battery 20, and is used to be closed in the direct connection charge-discharge mode or the step-up charge-discharge mode, that is, the battery 20 is connected to the DC bus of the motor drive circuit 1 through the positive main contactor K+ and the negative main contactor K-.

[0094] In addition, the charge-discharge system 10 further comprises a ninth switch K9, which is arranged on the connection line between the first end of the charge-discharge port 30 and the first end of each phase bridge arm, and is used to be closed in the direct connection charge-discharge mode or the step-up charge-discharge mode or the step-up charge mode.

[0095] In some embodiments of the present disclosure, the plurality of control switches K comprises a first switch K1 and a second switch K2, the first switch K1 is arranged between the neutral point of the first group of windings and the second end of the charge-discharge port 30, and the second switch K2 is arranged between the neutral point of the second group of windings and the second end of the charge-discharge port 30.

[0096] In the boost charging and discharging mode, when the first group of windings meets the target charging and discharging current, the first switch K1 is closed and the second switch K2 is opened, that is, the first group of windings in the motor 2 can be turned on to realize the operation of the battery 20 for boost charging and discharging. It can be understood that when the first group of windings is turned on, because the number of phase windings contained in the first group of windings is relatively small, even if the three-phase windings in the first group of windings are all turned on, the current carrying capacity on the N line is relatively weak, the current in the circuit is relatively small, and the inductance is large, which is suitable for small current boost charging and discharging of the battery 20; or, in the boost charging and discharging mode, when the first group of windings does not meet the target charging and discharging current, and the second group of windings meets the target charging and discharging current, the first switch K1 is opened and the second switch K2 is closed, that is, the second, third and fourth groups of windings in the motor 2 can be turned on to realize the operation of the battery 20 for boost charging and discharging. It can be understood that when the second group of windings is turned on, because the more neutral points connected by the second switch K2, the number of phase windings contained in the second group of windings is more than that in the first group of windings, and then the current carrying capacity on the N line is relatively strong after the second group of windings is turned on, the current in the circuit is also relatively large, which is suitable for large current boost charging and discharging of the battery 20; or, in the boost charging and discharging mode, when the second group of windings does not meet the target charging and discharging current, the first switch K1 and the second switch K2 are controlled to be closed, that is, all the windings in the motor 2 can be turned on to realize the operation of the battery 20 for boost charging and discharging. It can be understood that when the first group of windings and the second group of windings are turned on, the current carrying capacity on the N line is the strongest, and the current in the circuit is the largest, which is suitable for large current boost charging and discharging of the battery 20.

[0097] Specifically, for the working condition of small current charging and discharging, the switch with the largest inductance that meets the charging and discharging capacity is selected. For example, if the voltage of the charging and discharging port 30 is 420V, the maximum charging and discharging power is 10kW, and the maximum charging and discharging current is 24A, the first switch K1 can be selected to be closed and the second switch K2 to be opened. The number of parallel neutral points connected with the first switch K1 is small, the inductance of the winding is large, and the current carrying capacity on the N line can meet the demand.

[0098] And, for the working condition of large current charging and discharging, the switch is selected to meet the maximum charging and discharging capacity. For example, if the voltage of the charging and discharging port 30 is 470V, the maximum charging and discharging power is 120kW, and the maximum charging and discharging current is 255A, the first switch K1 can be selected to be open and the second switch K2 to be closed at this time. The number of parallel neutral points connected with the second switch K2 is large, and the current carrying capacity of the N line is stronger. The phase control can be used to meet the charging and discharging current ripple requirement. The bridge arm in the motor drive circuit 1 uses multi-phase bridge arm phase control. Through the cooperative control of charging and discharging and torque, the constant direction torque is given, the gear is engaged intermittently, and no matter where the rotor position is, there is basically no gear noise-vibration-harshness (NVH) noise.

[0099] Further, the switching state of each control switch and the current flow direction in the circuit in the boost charging and discharging mode of the embodiments of the present disclosure can be understood in combination with FIGS. 2-5. FIG. 2 is a schematic diagram of the current flow direction in the boost charging and discharging mode according to one embodiment of the present disclosure, FIG. 3 is a schematic diagram of the current flow direction in the boost charging and discharging mode according to another embodiment of the present disclosure, FIG. 4 is a schematic diagram of the current flow direction in the boost charging and discharging mode according to yet another embodiment of the present disclosure, and FIG. 5 is a schematic diagram of the current flow direction in the boost charging and discharging mode according to yet another embodiment of the present disclosure.

[0100] Among them, the cases shown in FIGS. 2-5 are the current flow direction when the first switch K1 is closed and the second switch K2 is open to realize the small current boost charging operation of the battery 20 when the first group of windings meets the target charging and discharging current.

[0101] Specifically, as shown in FIG. 2 and FIG. 3, when the battery 20 is boosted charging with a small current, it is confirmed that one phase of one set of windings in the first group of windings is turned on, that is, the A1 phase winding is turned on, which meets the requirement of the boosted charging and discharging current of the battery 20. Here, only the A1 phase winding is turned on as an example, the system 10 realizes the boosted charging process by controlling the first switch K1, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed. Specifically, in the energy storage process, as shown in FIG. 2, the lower bridge arm of the bridge arm for controlling the A1 phase winding in the motor drive circuit 1 is turned on, that is, the second power device VT2 is turned on, and the other power devices are not turned on. The current flows out from the second end of the charging and discharging port 30, flows back to the first end of the charging and discharging port 30 through the first switch K1, the A1 phase winding, the second power device VT2 and the ninth switch K9, and the energy storage process is completed. In the freewheeling process, as shown in FIG. 3, the upper bridge arm of the bridge arm for controlling the A1 phase winding in the motor drive circuit 1 is turned on, and the other power devices are not turned on. The current flows out from the second end of the charging and discharging port 30, flows back to the first end of the charging and discharging port 30 through the first switch K1, the A1 phase winding, the upper bridge arm of the A1 phase winding (for example, the first power device VT1, or the diode VD1, or the first power device VT1 and the diode VD1), the positive main contactor K+, the battery 20, the negative main contactor K- and the ninth switch K9, and the freewheeling process is completed. At this time, the boosted charging operation of the battery 20 is completed.

[0102] Specifically, as shown in FIG. 4 and FIG. 3, when the battery 20 is boosted charging with a small current, it is confirmed that one phase of one set of windings in the first group of windings is turned on, that is, the A1 phase winding is turned on, which meets the requirement of the boosted charging and discharging current of the battery 20. Here, only the A1 phase winding is turned on as an example, the system 10 realizes the boosted charging process by controlling the first switch K1, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed. Specifically, in the energy storage process, as shown in FIG. 2, the lower bridge arm of the bridge arm for controlling the A1 phase winding in the motor drive circuit 1 is turned on, that is, the second power device VT2 is turned on, and the other power devices are not turned on. The current flows out from the second end of the charging and discharging port 30, flows back to the first end of the charging and discharging port 30 through the first switch K1, the A1 phase winding, the second power device VT2 and the ninth switch K9, and the energy storage process is completed. In the freewheeling process, as shown in FIG. 3, the upper bridge arm of the bridge arm for controlling the A1 phase winding in the motor drive circuit 1 is turned on, and the other power devices are not turned on. The current flows out from the second end of the charging and discharging port 30, flows back to the first end of the charging and discharging port 30 through the first switch K1, the A1 phase winding, the upper bridge arm of the A1 phase winding (for example, the first power device VT1, or the diode VD1, or the first power device VT1 and the diode VD1), the positive main contactor K+, the battery 20, the negative main contactor K- and the ninth switch K9, and the freewheeling process is completed. At this time, the boosted charging operation of the battery 20 is completed.

[0103] In the energy storage process, as shown in FIG. 4, the lower bridge arms in all bridge arms for controlling the three-phase windings in the motor driving circuit 1 are controlled to be conductive, that is, the second power device VT2, the fourth power device VT4 and the sixth power device VT6 are controlled to be conductive, the first power device VT1, the third power device VT3 and the fifth power device VT5 and their corresponding diodes are not conductive, the current flows out from the second end of the charge-discharge port 30, passes through the first switch K1, then passes through the A1-phase winding, the B1-phase winding and the C1-phase winding, and then passes through the second power device VT2, the fourth power device VT4 and the sixth power device VT6 respectively, and then flows back to the first end of the charge-discharge port 30 through the ninth switch K9, to complete the energy storage process. In the freewheeling process, as shown in FIG. 5, the upper bridge arms in all bridge arms for controlling the three-phase windings in the motor driving circuit 1 are controlled to be conductive, the second power device VT2, the fourth power device VT4 and the sixth power device VT6 are controlled to be not conductive, the current flows out from the second end of the charge-discharge port 30, passes through the A1-phase winding, the B1-phase winding and the C1-phase winding, and then passes through the upper bridge arm (for example, the first power device VT1, or the diode VD1, or the first power device VT1 and the diode VD1) of the A1-phase winding, the upper bridge arm (for example, the third power device VT3, or the diode VD3, or the third power device VT3 and the diode VD3) of the B1-phase winding and the upper bridge arm (for example, the fifth power device VT5, or the diode VD5, or the fifth power device VT5 and the diode VD5) of the C1-phase winding respectively, and then flows back to the first end of the charge-discharge port 30 through the positive main contactor K+, the battery 20, the negative main contactor K- and the ninth switch K9, to complete the freewheeling process, and at this time, the boosting charging operation on the battery 20 is completed.

[0104] Based on the above, by using the neutral points n of different numbers of parallel connections led out by the motor 2, the equivalent phase inductance of the motor 2 is different, the current passing through the N line has different capacities, the more the number of parallel neutral points of the same group of windings, the stronger the current passing through the N line, the smaller the inductance, and the larger the ripple on the inductance. Based on this, by selecting different numbers of neutral points to be led out according to the requirements of the charging and discharging power and the inductance, and selecting a proper number of neutral points n to be led out in parallel, in the boosting charging and discharging mode, the system can confirm the number of windings needed to work according to the target charging and discharging current, and further control the switching states of the first switch K1 and the second switch K2, that is, select different switches to be closed according to different target charging and discharging currents, to meet the requirements of the inductance and the overcurrent capacity of the charging and discharging circuit and meet the requirements of the phase current ripple and the efficiency of the charging and discharging system.

[0105] Further, in some other embodiments, as shown in FIG. 6, a schematic diagram of the charge-discharge system 10 according to another embodiment of the present disclosure is shown, wherein the second end of each phase bridge arm is also connected to the second end of the charge-discharge port 30; the charge-discharge system 10 further comprises an eighth switch K8, which is arranged on the connection line between the second end of the bridge arm and the second end of the charge-discharge port 30, and is used to be closed in the direct connection charge-discharge mode or the boost charge-discharge mode. In the direct connection charge-discharge mode, the system 10 controls the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed, so as to realize the direct connection charge-discharge operation of the battery 20.

[0106] In some embodiments of the present disclosure, the neutral point of at least one group of windings is also connected to the positive terminal of the battery 20. Specifically, in some embodiments, as shown in FIG. 7, a schematic diagram of the charge-discharge system 10 according to another embodiment of the present disclosure is shown, wherein the neutral point of the first group of windings is connected to the positive terminal of the battery 20.

[0107] As shown in FIG. 7, the plurality of control switches K comprises a third switch K3, which is arranged between the neutral point n1 of the first group of windings and the positive terminal of the battery 20, and is used to be closed in the boost charge-discharge mode.

[0108] In the boost charge-discharge mode, the current flowing direction of the battery 20 when the battery 20 is charged with a small current boost can be understood in combination with FIG. 7, so as to confirm that one phase of one set of windings in the first group of windings is turned on, that is, the requirement of the boost charge-discharge current of the battery 20 can be met, and here, only the A1 phase winding is taken as an example for description, the charge-discharge system 10 controls the third switch K3, the eighth switch K8, the ninth switch K9 and the negative main contactor K- to be closed. The upper bridge arm in the bridge arm for controlling the A1 phase winding in the motor drive circuit 1 is controlled to be turned on, and other power devices are not turned on. The current flows out from the second end of the charge-discharge port 30, flows back to the first end of the charge-discharge port 30 through the eighth switch K8, the upper bridge arm (for example, the first power device VT1) of the A1 phase winding, the A1 phase winding, the third switch K3, the battery 20, the negative main contactor K- and the ninth switch K9, and one boost charge operation of the battery 20 is completed.

[0109] In some other embodiments, as shown in FIG. 7, wherein the neutral point of the first group of windings is also connected to the neutral point of the second group of windings; the plurality of control switches K further comprises a fourth switch K4, which can be arranged on the connection line between the neutral point of the first group of windings and the neutral point of the second group of windings, and is used to be closed when the first group of windings cannot meet the target charge-discharge current in the boost charge-discharge mode.

[0110] Specifically, in the boost charge-discharge mode, when the first group of windings meets the target charge-discharge current, the system 10 controls the third switch K3, the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed, so as to realize the small-current boost charge-discharge operation of the battery 20. When the first group of windings does not meet the target charge-discharge current, the system 10 controls the third switch K3, the fourth switch K4, the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed, so as to realize the large-current boost charge-discharge operation of the battery 20. In addition, when the battery 20 needs to be charged with a large current, the current flow direction in the circuit can be understood in combination with the content of the current flow direction in the small-current boost charge-discharge mode, which will not be described herein again.

[0111] In some embodiments of the present disclosure, the neutral point of at least one group of windings in the plurality of groups of windings is connected to the second end of the charge-discharge port 30 through a control switch K, and the neutral points of the windings other than the winding connected to the second end of the charge-discharge port 30 are connected to the positive terminal of the battery 20 through a control switch K.

[0112] In some embodiments of the present disclosure, in the boost charge-discharge mode, the control switch K provided on the connection line between the neutral point and the second end of the charge-discharge port is closed; or in the boost charge-discharge mode, the control switch K provided on the connection line between the neutral point and the positive terminal of the battery is closed.

[0113] In some embodiments of the present disclosure, the plurality of groups of windings include windings with different numbers of winding sets. For the case that the plurality of groups of windings include windings with different numbers of winding sets, FIG. 8 is a schematic diagram of a charge-discharge system 10 according to another embodiment of the present disclosure.

[0114] Taking the case that the first group of windings includes one winding set and the second group of windings includes three winding sets as an example, the case will be described in detail. Specifically, as shown in FIG. 8, in the boost charge-discharge mode, when the first group of windings meets the target charge-discharge current, the system 10 controls the first switch K1, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed, so as to realize the small-current boost charge-discharge operation of the battery 20. When the first group of windings does not meet the target charge-discharge current, the system 10 controls the first switch K1, the second switch K2, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed, so as to realize the large-current boost charge-discharge operation of the battery 20. For the case that the plurality of groups of windings include windings with different numbers of winding sets, the current flow direction in the circuit in the boost charge-discharge mode and the process of controlling each bridge arm to be turned on or off to realize energy storage and freewheeling in the boost charge-discharge mode and the boost charge-discharge mode can be understood in combination with FIGS. 2-5 and the content of the current flow direction in the small-current boost charge-discharge mode, which will not be described herein again.

[0115] In some embodiments of the present disclosure, the number of sets of windings included in the plurality of sets of windings is the same. For the case where the number of sets of windings included in the plurality of sets of windings is the same. As shown in FIG. 9, it is a schematic diagram of the charge-discharge system 10 according to yet another embodiment of the present disclosure, wherein the motor 2 includes a third set of windings and a fourth set of windings, the number of sets of windings included in the third set of windings is the same as the number of sets of windings included in the fourth set of windings; specifically, in some embodiments, the third set of windings includes two sets of windings, and the fourth set of windings includes two sets of windings.

[0116] Specifically, the neutral pole of the third set of windings is connected to the second end of the charge-discharge port 30, and the neutral pole of the fourth set of windings is connected to the positive end of the battery 20. In some embodiments, the plurality of control switches K includes a fifth switch K5 and a sixth switch K6.

[0117] Wherein the fifth switch K5 is arranged on the connecting line between the neutral pole of the third set of windings and the second end of the charge-discharge port 30, and is used to be closed in the boost charge-discharge mode; the sixth switch K6 is arranged on the connecting line between the neutral pole of the fourth set of windings and the positive end of the battery 20, and is used to be closed in the boost charge-discharge mode.

[0118] And in some embodiments, the neutral pole of the third set of windings is connected to the neutral pole of the fourth set of windings; the plurality of control switches K further includes a seventh switch K7, the seventh switch K7 is arranged on the connecting line between the neutral pole of the third set of windings and the neutral pole of the fourth set of windings, and is used to be closed when the third set of windings does not meet the target charge-discharge current in the boost charge-discharge mode, or is used to be closed when the fourth set of windings does not meet the target charge-discharge current in the boost charge-discharge mode.

[0119] Specifically, in the boost charging and discharging mode, when the third group of windings meets the target charging and discharging current, the charging and discharging system 10 controls the fifth switch K5, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed for realizing the small current boost charging and discharging operation of the battery 20. When the third group of windings does not meet the target charging and discharging current, the system controls the fifth switch K5, the seventh switch K7, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed for realizing the large current boost charging and discharging operation of the battery 20. In the boost current charging and discharging mode, when the fourth group of windings meets the target charging and discharging current, the charging and discharging system 10 controls the sixth switch K6, the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed for realizing the small current boost charging and discharging operation of the battery 20. When the fourth group of windings does not meet the target charging and discharging current, the charging and discharging system 10 controls the sixth switch K6, the seventh switch K7, the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed for realizing the large current boost charging and discharging operation of the battery 20. In the direct connection charging and discharging mode, the charging and discharging system 10 controls the eighth switch K8, the ninth switch K9, the positive main contactor K+ and the negative main contactor K- to be closed for realizing the direct connection charging and discharging operation of the battery 20.

[0120] For the case that the number of windings included in each group of windings is the same, the current flow directions in the circuits in the boost charging and discharging mode, the boost current charging and discharging mode and the direct connection charging and discharging mode, and the processes of realizing energy storage and freewheeling by controlling the conduction or closing of each bridge arm in the boost charging and discharging mode and the boost current charging and discharging mode can be understood in combination with the above embodiments, which will not be described here in detail.

[0121] In some embodiments of the present disclosure, as shown in FIGS. 7-9, the charging and discharging system 10 further includes a pre-charging unit 50 which is closed during charging and discharging, wherein the pre-charging unit 50 is arranged in parallel with the positive main contactor K+. The pre-charging unit 50 includes a pre-charging switch K0 and a pre-charging resistor R connected in series. In addition, the charging and discharging system 10 further includes a bus capacitor C1 and a charging and discharging port capacitor C2. The bus capacitor C1 is connected across the positive DC bus and the negative DC bus, and the bus capacitor C1 is located between the battery 20 and the motor drive circuit 1; the first end of the charging and discharging port capacitor C2 is connected to the first end of the charging and discharging port 30, and the second end of the charging and discharging port capacitor C2 is connected to the second end of the charging and discharging port 30.

[0122] Based on the above, the charging and discharging system 10 according to the embodiments of the present disclosure can select different control switches to be closed according to different charging and discharging currents in the stage of charging and discharging the battery 20 at a small power, so as to meet the requirements of the charging and discharging loop for inductance and overcurrent capacity, and meet the requirements of the phase current ripple and the charging and discharging system efficiency.

[0123] In some embodiments of the present disclosure, another charging and discharging system 10 is also proposed, as shown in FIG. 10, which is a schematic diagram of the charging and discharging system 10 according to an embodiment of the present disclosure. The charging and discharging system 10 includes a motor drive circuit 1, a motor 2, and a plurality of control switches K.

[0124] The motor drive circuit 1 includes a plurality of bridge arms connected in parallel, each bridge arm is connected across the positive and negative poles of the battery 20, and the first end of each bridge arm is also connected to the first end of the charging and discharging port 30.

[0125] The motor 2 includes a plurality of groups of windings, each group of windings includes at least one set of windings, each set of windings includes a plurality of phase windings, the first end of each phase winding in each set of windings is connected to the midpoint of the corresponding phase bridge arm, the second ends of the phase windings in each set of windings are connected together, and the first end of at least one phase winding in the plurality of phase windings is connected to the midpoint of the corresponding phase bridge arm through a wire harness. Specifically, for the motor drive circuit 1, the plurality of phase windings of the motor 2, and the connection and control therebetween, they can be understood in combination with the above embodiments, and will not be described here.

[0126] The plurality of control switches K are arranged on the wire harness, and are used to switch according to the target charging and discharging mode to form a corresponding charging and discharging loop.

[0127] Specifically, as shown in FIG. 10, the charging and discharging system 10 includes a positive main contactor K+ and a negative main contactor K-. The positive main contactor K+ is arranged on the wire connecting the second end of each phase bridge arm and the positive pole of the battery 20, and is used to be closed in the direct connection charging and discharging mode or the step-up charging and discharging mode. The negative main contactor K- is arranged on the wire connecting the first end of each phase bridge arm and the negative pole of the battery 20, and is used to be closed in the direct connection charging and discharging mode or the step-up charging and discharging mode. That is, the battery 20 is connected to the DC bus of the motor drive circuit 1 through the positive main contactor K+ and the negative main contactor K-.

[0128] The plurality of control switches K includes a tenth switch K10 and an eleventh switch K11. The tenth switch K10 is disposed on a connection line between the first end of the charge-discharge port 30 and the first end of each phase bridge arm, and is used to be closed in the direct connection charge-discharge mode or the step-up charge-discharge mode or the step-up current charge mode. The eleventh switch K11 is disposed on a connection line between the second end of the charge-discharge port 30 and the midpoint C of the third phase bridge arm, and is used to be closed in the step-up charge-discharge mode.

[0129] In the step-up charge-discharge mode, the system 10 controls the tenth switch K10 and the eleventh switch K11 to be closed, and the positive main contactor K+ and the negative main contactor K- to be closed to implement the step-up charge process. Specifically, in the energy storage process, the lower bridge arm in the bridge arm for controlling at least one of the A-phase winding and the B-phase winding in the motor drive circuit 1 is controlled to be conductive, that is, at least one of the second power device VT2 and the fourth power device VT4 is controlled to be conductive, and the other power devices are not conductive. The current flows out from the second end of the charge-discharge port 30, flows back to the first end of the charge-discharge port 30 through the eleventh switch K11, the C-phase winding, the A-phase winding and / or the B-phase winding, the second power device VT2 and / or the fourth power device VT4, and the tenth switch K10, to complete the energy storage process. In the freewheeling process, the upper bridge arm in the bridge arm for controlling the A-phase winding and / or the B-phase winding in the motor drive circuit 1 is controlled to be conductive, and the other power devices are not conductive. The current flows out from the second end of the charge-discharge port 30, flows back to the first end of the charge-discharge port 30 through the eleventh switch K11, the C-phase winding, the A-phase winding and / or the B-phase winding, the upper bridge arm of the A-phase winding (for example, the first power device VT1, or the diode VD1, or the first power device VT1 and the diode VD1), and / or the upper bridge arm of the B-phase winding (for example, the third power device VT3, or the diode VD3, or the third power device VT3 and the diode VD3), the positive main contactor K+, the battery 20, the negative main contactor K-, and the tenth switch K10, to complete the freewheeling process, and thus one step-up charge operation on the battery 20 is completed.

[0130] In addition, the plurality of control switches K includes a twelfth switch K12 and a thirteenth switch K13. The twelfth switch K12 is disposed on a connection line between the second end of the charge-discharge port 30 and the first end of each phase bridge arm, and is used to be closed in the direct connection charge-discharge mode or the step-up current charge mode. The thirteenth switch K13 is disposed on a connection line between the midpoint A of the first phase bridge arm and the positive end of the battery 20, and is used to be closed in the step-up current charge mode.

[0131] Wherein, when the battery 20 is subjected to the boost charging, the system 10 controls the tenth switch K10, the twelfth switch K12, the thirteenth switch K13 and the negative main contactor K- to be closed. The motor drive circuit 1 is controlled to control the upper bridge arm in the bridge arm of at least one of the B-phase winding and the C-phase winding to be conductive, and other power devices are not conductive. The current flows out from the second end of the charging and discharging port 30, flows back to the first end of the charging and discharging port 30 through the twelfth switch K12, the third power device VT3 and / or the fifth power device VT5, the B-phase winding and / or the C-phase winding, the A-phase winding, the thirteenth switch K13, the battery 20, the negative main contactor K- and the tenth switch K10, to complete a boost charging operation of the battery 20.

[0132] In addition, when the battery 20 is subjected to the direct charging, the system 10 controls the tenth switch K10, the twelfth switch K12, the positive main contactor K+ and the negative main contactor K- to be closed, to realize the charging of the battery 20 directly by the charging and discharging port 30.

[0133] According to the charging and discharging system 10 provided by the embodiments of the present disclosure, the neutral points of the multiple groups of windings of the motor 2 are not led out of the wire harness, but are led out of the wire harness between the first end of at least one of the multiple phase windings and the midpoint of the multiple phase bridge arms, and are connected with at least one of the second end of the charging and discharging port 30 and the positive terminal of the battery 20, and multiple control switches K are arranged on the led-out wire harness, and the switching states of the multiple control switches K are controlled according to the target charging and discharging mode, to form a corresponding charging and discharging loop, that is, by the switching states of the multiple control switches K, the requirements of different target charging and discharging modes can be met, and multiple charging and discharging functions can be realized.

[0134] In some embodiments of the present disclosure, a charging and discharging control method is also provided for the charging and discharging system 10 of any one of the embodiments, as shown in FIG. 11, which is a flow chart of the charging and discharging control method according to an embodiment of the present disclosure, wherein the charging and discharging control method further comprises steps S1 and S2, which are specifically as follows.

[0135] S1, obtaining a target charging and discharging current.

[0136] In some embodiments of the present disclosure, the target charging and discharging current is the minimum current value among the first charging and discharging current, the second charging and discharging current and the third charging and discharging current; wherein the first charging and discharging current is obtained according to the motor winding temperature, the motor rotor temperature and the power device temperature; the second charging and discharging current is obtained according to the battery SOC, the minimum voltage of the battery, the current voltage of the battery, the maximum voltage of the battery and the battery temperature; and the third charging and discharging current is obtained according to the current voltage platform of the charging pile, the charging and discharging state of the charging gun and the charging and discharging power of the charging gun.

[0137] It can be understood that the battery SOC and temperature, etc. all affect the charging and discharging current. For example, the battery charging and discharging current is affected by temperature, the lower or higher the temperature is, the smaller the current is; for example, the battery charging current is affected by the current SOC of the battery, the higher the SOC is, the smaller the current is; the battery discharging current is affected by the current SOC of the battery, the higher the SOC is, the larger the current is, which is contrary to charging. Compared with low temperature and normal temperature, high temperature has the greatest impact on fast charging and fast discharging. Within the temperature range that the battery can withstand, the battery performance generally improves with the increase of temperature. The charging time at normal temperature of 20-35℃ is the shortest, the low temperature is the second, and the fast charging time at high temperature is the longest, which shows that high temperature has the greatest impact on fast charging, that is, the higher the temperature is, the longer the fast charging time is.

[0138] Specifically, the first charging and discharging current is the maximum charging and discharging current under the current state of motor electric control. The charging and discharging system calculates the maximum current IBCT that can be charged and the maximum current IDC1 that can be discharged according to the current motor winding temperature, motor rotor temperature and power device temperature, that is, the first charging and discharging current. Among them, the motor rotor temperature can be estimated according to the permanent magnet synchronous motor magnet temperature, electrically excited rotor winding and asynchronous motor rotor temperature.

[0139] The second charging and discharging current is the maximum charging and discharging current under the current state of the battery. The battery manager can provide the minimum voltage, current voltage and maximum voltage of the current battery, etc. According to the current battery SOC and battery temperature, the maximum charging current IBCT required for charging and the maximum current IDC2 that can be discharged, that is, the second charging and discharging current, are calculated.

[0140] The third charging and discharging current is the maximum charging and discharging current under the current state of the charging pile. The charging pile can calculate the maximum current IBCT that the battery can charge and the maximum current IDC3 that the battery can discharge according to the current pile voltage platform, the charging and discharging state of the charging gun and the charging and discharging power of the charging gun, that is, the third charging and discharging current, wherein the charging gun can be single gun or double gun.

[0141] Further, when the battery is charged and discharged, the power distribution unit (PDC) interacts with the battery manager, the micro control unit (MCU) and the charging pile to obtain the charging current and discharging current information, and each component sends the new allowed charging or discharging current in real time according to the state of the charging or discharging. According to the current charging and discharging system, the state of the battery and the charging pile, the PDC and other managers arbitrate in real time to select the maximum charging current IBCmax allowed in the safe and reliable charging state, or the maximum discharging current IDCmax allowed in the safe and reliable discharging state as the target charging and discharging current. Among them, the target charging and discharging current is the minimum current value among the first charging and discharging current, the second charging and discharging current and the third charging and discharging current obtained above, to ensure the safety of charging and discharging.

[0142] S2, according to the target charging and discharging current and the target charging and discharging mode, control the switching state of the plurality of control switches arranged on the lead-out wire harness of the neutral point of the plurality of groups of windings in the charging and discharging system, to control the corresponding number of windings to form a charging and discharging loop.

[0143] Among them, the target charging and discharging mode includes a boost charging and discharging mode, a boost current charging and discharging mode and a direct connection charging and discharging mode, and the target charging and discharging mode can be determined according to the charging voltage output by the charging pile, the battery voltage and the voltage of the external electrical appliance. Taking battery charging as an example, if the battery voltage is relatively low, the battery can be charged in the boost charging mode, that is, the boost current charging mode; if the battery voltage is relatively high, the battery can be charged in the boost charging mode or the direct connection charging mode. Among them, the specific charging and discharging mode can be automatically selected by the system, and under the target charging and discharging mode, the charging pile voltage needs to be adjusted according to the current battery voltage and the voltage range that the charging pile can provide, to make the best match and maximize the reduction of the voltage difference between the battery and the charging pile, and when the charging port voltage cannot be dynamically adjusted, the charging port allows the fixed voltage to be controlled.

[0144] According to the above decision of the target charging and discharging current and the target charging and discharging mode, the MCU combines the setting of the plurality of control switches arranged on the lead-out wire harness, combines it with the control algorithm of the target charging and discharging current and the target charging and discharging mode, selects different control switches to meet the demand of the battery and the multi-phase motor for charging and discharging power and efficiency.

[0145] According to the charging and discharging control method provided in the embodiments of the present disclosure, the hardware structure and the control algorithm of the charging and discharging system are combined through the charging and discharging system for any one of the above, and the switching state of the plurality of control switches can control as few windings as possible to meet the requirements of different target charging and discharging modes and target charging and discharging currents, thereby reducing the number of windings participating in work, increasing inductance, reducing ripple, reducing loss, meeting the requirements of inductance and overcurrent capacity of the charging and discharging circuit, meeting the requirements of phase current ripple and charging and discharging system efficiency, and effectively improving the charging and discharging efficiency of the battery, especially for small power charging and discharging working conditions.

[0146] In some embodiments of the present disclosure, as shown in FIG. 12, a flowchart of a charging and discharging control method according to another embodiment of the present disclosure is shown, wherein the charging and discharging control method further comprises step S3, which is as follows.

[0147] S3, controlling the switching state of the multi-phase bridge arm of the charging and discharging system according to the target charging and discharging current and the rotor position of the motor.

[0148] Among them, the number of winding phases required to form the charging and discharging circuit is determined according to the target charging and discharging current.

[0149] Among them, single-phase or multi-phase windings can be selected to participate in charging and discharging control for a multi-phase motor, such as three-phase winding phase error, two-phase winding phase error and single-phase winding control. When the single-phase winding charging and discharging current meets the charging and discharging current demand, the single-phase winding is preferentially selected for charging and discharging control, and when the single-phase winding does not meet the charging and discharging current demand, the number of motor winding phases is continuously increased until the charging and discharging current power demand is met, thereby achieving the effect of large single-phase winding inductance, small charging and discharging ripple and highest charging and discharging efficiency under the same charging power working condition.

[0150] Then, the target phase winding corresponding to the number of winding phases is determined according to the rotor position of the motor, and the switching state of the target phase winding corresponding to the target phase bridge arm is controlled.

[0151] Among them, there is a gap between the rotor of the motor and the gear of the reducer. Even if the wheels are fixed, the rotor of the motor can rotate within a certain range θ1 to θ2 due to the existence of the gear gap. Thus, the angle through which the rotor of the motor can rotate can be obtained. It can be understood that for a multi-phase motor, no matter how many winding phases participate in the charging and discharging process, the target phase winding can be selected according to the principle that the magnetic field generated by the number of winding phases used in the multi-phase motor has the smallest angle with the magnetic field direction of the D-axis of the rotor. This way can ensure that the torque generated by the motor during charging and discharging is the smallest, avoid abnormal noise of the whole vehicle and excessive torque stress of the motor, and damage the brake system, etc.

[0152] For example, taking a target phase winding as a single-phase winding, according to the rotor position control target phase winding corresponding to the target phase bridge arm conduction, the control target phase winding corresponding to the target phase bridge arm conduction can be selected based on the minimum torque principle, or the control target phase winding corresponding to the target phase bridge arm conduction can be selected based on the minimum stator and rotor magnetic field angle principle, or the control target phase winding corresponding to the target phase bridge arm conduction can be selected based on the maximum winding inductance principle of the charging and discharging circuit.

[0153] Hereinafter, taking a single-phase winding as an A1-phase winding or a B1-phase winding or a C1-phase winding as an example for description.

[0154] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, the single-phase winding is a single-phase winding in a multi-phase winding that generates the smallest torque when the magnetic field generated by the single-phase winding is combined with the magnetic field generated by the rotor, or when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, and the multi-phase winding is a winding that generates the smallest torque when the superimposed magnetic field generated by the winding is combined with the magnetic field generated by the rotor.

[0155] It can be understood that the control target phase winding corresponding to the target phase bridge arm conduction can be selected based on the minimum torque principle. The single-phase winding that generates the smallest torque when the magnetic field generated by the stator winding is combined with the D-axis magnetic field is selected for charging and discharging. The D-axis magnetic field is the direction of the rotor magnetic field, that is, the direction of the N-pole magnetic field line of the rotor. Specifically, the selected target phase winding needs to make the rotor have the smallest position rotation and the smallest torque generated in the charging and discharging process. According to the direction of the magnetic field generated by the rotor, the single-phase winding of the stator selected to charge or discharge is the single-phase winding that generates the smallest torque when the magnetic field generated by the single-phase winding current is combined with the magnetic field generated by the rotor. The single-phase bridge arm and the corresponding single-phase winding are selected for charging or discharging. The magnetic field combined torque is the smallest, which ensures that there is no torque fluctuation during the charging and discharging switching process and after the switching is completed, and even causes gear abnormal sound and other micro-noise. There is a small rotation of the rotor position caused by the magnetic field generated by the stator in the charging or discharging starting stage, which causes the selected best winding to change. The gears can be engaged before charging and discharging to avoid current fluctuation caused by winding switching during the charging and discharging process.

[0156] For the method of selecting a single-phase bridge arm for charging and discharging, the single-phase bridge arm and the corresponding single-phase winding can be selected for charging or discharging according to the minimum torque generated when the magnetic field generated by the rotor is combined with the magnetic field generated by the single-phase winding charging or discharging current. The magnetic field combined torque is the smallest, which ensures that there is no torque fluctuation during the switching process and after the switching is completed, and even causes gear abnormal sound and other micro-noise. The magnetic field combined torque is the smallest, so that the torque received by the motor rotor is the smallest, and the rotation angle is the smallest. In this way, the motor phase current can pass through a larger current, ensuring that the charging and discharging power is the largest, and the electronic brake is not damaged or the vehicle wheel is not rotated.

[0157] Wherein, the selection of the target phase winding based on the minimum torque principle can be understood in combination with Fig. 13, which is a schematic diagram of the selection of the area of the single-phase winding based on the minimum torque principle according to an embodiment of the present disclosure.

[0158] Specifically, in combination with Fig. 13, the judgment method that the stator magnetic field generated by the single-phase winding and the rotor magnetic field are combined to have the minimum torque is as follows: when the battery is in the charging state, the phase current of the single-phase winding is from the N line to the phase terminal, and the generated magnetic field is opposite to the normal driving phase terminal. When the motor rotor position is in the sector-30 to 30 and 150 to 210 degrees of electrical angle, the A1 phase winding is selected for charging; when the motor rotor position is in the sector 90 to 150 and 270 to 330 degrees of electrical angle, the B1 phase winding is selected for charging; and when the motor rotor position is in the sector 30 to 90 and 210 to 270 degrees of electrical angle, the C1 phase winding is selected for charging.

[0159] In addition, when the battery is in the discharging state, the phase current of the single-phase winding is from the phase terminal to the N line, and the generated magnetic field is the same as the normal driving phase terminal. When the motor rotor position is in the sector-30 to 30 and 150 to 210 degrees of electrical angle, the A1 phase winding is selected for charging; when the motor rotor position is in the sector 90 to 150 and 270 to 330 degrees of electrical angle, the B1 phase winding is selected for charging; and when the motor rotor position is in the sector 30 to 90 and 210 to 270 degrees of electrical angle, the C1 phase winding is selected for charging. The angle of the selected winding position is consistent with that in the charging state.

[0160] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, the single-phase winding is a single-phase winding in which the included angle between the direction of the generated magnetic field and the direction of the magnetic field generated by the rotor is the smallest, or, when the single-phase winding does not satisfy the target charging and discharging current, the target phase winding is a multi-phase winding, and the multi-phase winding is a winding in which the included angle between the direction of the generated superimposed magnetic field and the direction of the magnetic field generated by the rotor is the smallest.

[0161] It can be understood that the conduction of the target phase bridge arm corresponding to the target phase winding can be selected based on the minimum stator and rotor magnetic field included angle principle. A certain phase winding close to the direction of the rotor magnetic field is selected for charging and discharging. According to the direction of the magnetic field generated by the rotor, the magnetic field position generated by the charging or discharging current of the selected target phase winding is closest to the direction, that is, the minimum stator and rotor magnetic field included angle, and the single-phase bridge arm and the corresponding target phase winding are selected for charging or discharging, so that the minimum stator and rotor magnetic field included angle is obtained. Even if the magnetic field generated by the stator causes a slight rotation of the rotor position at the beginning of the charging or discharging, the selected target phase winding will not change, avoiding the current fluctuation caused by the switching of the target phase winding during the charging and discharging process, ensuring that there is no torque fluctuation during the switching process and after the switching is completed, and even causing gear abnormal sound and other micro-noise.

[0162] For the method of selecting the charging and discharging of the single-phase bridge arm, according to the position of the magnetic field generated by the rotor close to the position of the magnetic field generated by the charging or discharging current of the single-phase bridge arm, the single-phase bridge arm and the corresponding single-phase winding are selected to be charged or discharged, so as to ensure that there is no torque fluctuation during switching and after switching, and even cause gear abnormal sound and other micro-noise. The stator magnetic field closest to the direction of the rotor magnetic field is generated, so that the motor rotor is subjected to a single direction torque. Even if the slight rotation of the rotor position caused by the magnetic field generated by the stator in the charging or discharging starting stage, the selected single-phase winding will not change. However, compared with the winding selected based on the minimum torque principle, the torque generated during charging and discharging is large.

[0163] Wherein, the case of selecting the target phase winding based on the minimum stator and rotor magnetic field angle principle of the embodiment of the present disclosure can be understood in combination with FIG. 14, which is a schematic diagram of the area of selecting a single-phase winding based on the minimum stator and rotor magnetic field angle principle according to one embodiment of the present disclosure.

[0164] Specifically, the minimum torque judgment method of the stator magnetic field and the rotor magnetic field combined with FIG. 14 is that: in the charging state of the battery, the process of the single-phase winding phase current flowing from the N line to the phase terminal, the generated magnetic field is opposite to the normal driving phase terminal. When the motor rotor position is in 120 to 240 degrees of electrical angle, select A1 phase winding to charge, for example: wherein the same charging current rotor position selects A1 phase winding from 120 to 150 will generate larger torque than selecting B1 phase winding, and the same charging current rotor position selects A1 phase winding from 210 to 240 will generate larger torque than selecting C1 phase winding, but the stator magnetic field and the rotor magnetic field angle is small. When the motor rotor position is in 240 to 360 degrees of electrical angle, select B1 phase winding to charge; when the motor rotor position is in 0 to 120 degrees of electrical angle, select C1 phase winding to charge.

[0165] And, in the discharging state of the battery, the process of the single-phase winding phase current flowing from the phase terminal to the N line, the generated magnetic field is the same as the normal driving phase terminal. When the motor rotor position is in -60 to 60 degrees of electrical angle, select A1 phase winding to charge; when the motor rotor position is in 60 to 180 degrees of electrical angle, select B1 phase winding to charge; when the motor rotor position is in 180 to 300 degrees of electrical angle, select C1 phase winding to charge.

[0166] In some embodiments of the present disclosure, the target phase winding is a single-phase winding, the single-phase winding is a single-phase winding in a multi-phase winding that has the smallest angle with the positive or negative 90-degree direction of the direction of the magnetic field generated by the rotor, or, when the single-phase winding does not satisfy the target charging and discharging current, the target phase winding is a multi-phase winding, and the multi-phase winding is a winding that has the smallest angle with the positive or negative 90-degree direction of the direction of the magnetic field generated by the rotor.

[0167] It can be understood that the conduction of the target phase bridge arm corresponding to the target phase winding can be selected based on the winding inductance maximization principle of the charging and discharging circuit. A certain phase winding close to the positive or negative direction of the Q-axis is selected for charging and discharging. Among them, the rotor position after the meshing gear gap is taken as the standard (here, θ1 or θ2), the selected target phase winding makes the rotor have the smallest position rotation, and according to the positive or negative 90-degree direction of the D-axis magnetic field position generated by the rotor (the positive or negative direction of the Q-axis, the Q-axis is perpendicular to the D-axis magnetic field direction), the magnetic field position generated by the charging or discharging current close to the single-phase winding is selected in this direction, and then the single-phase bridge arm and the corresponding single-phase winding are selected for charging or discharging, so as to maximize the inductance of the target phase winding in the process of charging and discharging switching. During the charging and discharging process, the charging current or discharging current direction will generate a single direction torque to mesh the gear, and after the switching is completed, there will be no torque fluctuation, and even cause gear abnormal sound and other micro-noise. The winding inductance maximization principle has large charging and discharging inductance, charging and discharging ripple efficiency, and higher efficiency, but also causes the maximum synthesis torque of the stator and rotor magnetic field, and the excessive charging or discharging current may damage the electronic brake or make the vehicle wheel rotate, so it is necessary to select appropriate charging and discharging current to avoid damaging vehicle parts.

[0168] For the method of selecting single-phase bridge arm charging and discharging switching, the stator magnetic field generated by the single-phase winding is closest to the positive or negative 90-degree direction of the rotor magnetic field, so that the motor rotor is subjected to a single direction torque to mesh the gear, and after the meshing is completed, it will not cause gear abnormal sound and other micro-noise, and the inductance of the single-phase winding selected by the charging and discharging circuit is the largest, which reduces the charging and discharging current ripple, reduces the loss, and improves the efficiency. The maximum charging and discharging current of the single-phase winding is limited to avoid damaging the electronic brake or making the vehicle wheel rotate. During the single-phase charging or discharging process, the carrier frequency strategy of the bridge arm of the motor drive circuit is added to achieve a larger charging or discharging current, and at the same time, the charging or discharging efficiency can be improved.

[0169] In some embodiments of the present disclosure, the target phase winding can be selected based on the winding inductance maximization principle of the charging and discharging circuit, and the situation of the target phase winding can be understood in combination with FIG. 15. FIG. 15 is a schematic diagram of a region for selecting a single-phase winding based on the winding inductance maximization principle of the charging and discharging circuit according to an embodiment of the present disclosure.

[0170] Specifically, in combination with FIG. 15, the judgment method that the stator magnetic field generated by the single-phase winding is closest to the positive or negative 90-degree direction of the rotor D-axis magnetic field is as follows: when the battery is in a charging state, during the process that the single-phase winding phase current flows from the N line to the phase terminal, the generated magnetic field is opposite to the normal driving phase terminal flow. When the motor rotor position is in the range of 60 to 120 or 240 to 300 degrees of electrical angle, the A1 phase winding is selected for charging; when the motor rotor position is in the range of 0 to 60 or 180 to 240 degrees of electrical angle, the B1 phase winding is selected for charging; and when the motor rotor position is in the range of 120 to 180 or 300 to 360 degrees of electrical angle, the C1 phase winding is selected for charging.

[0171] In addition, when the battery is in a discharging state, during the process that the single-phase winding phase current flows from the phase terminal to the N line, the generated magnetic field is the same as the normal driving phase terminal flow. When the motor rotor position is in the range of 60 to 120 or 240 to 300 degrees of electrical angle, the A1 phase winding is selected for discharging; when the motor rotor position is in the range of 0 to 60 or 180 to 240 degrees of electrical angle, the B1 phase winding is selected for discharging; and when the motor rotor position is in the range of 120 to 180 or 300 to 360 degrees of electrical angle, the C1 phase winding is selected for discharging.

[0172] In some embodiments of the present disclosure, when the target phase winding is a multi-phase winding, the multi-phase winding is controlled in a uniform phase difference or in a same phase.

[0173] It can be understood that when the single-phase winding charging and discharging current meets the charging and discharging current demand, the single-phase winding is preferentially selected for charging and discharging control; when the single-phase winding does not meet the charging and discharging current demand, the number of motor winding phases is continuously increased, and then the motor multi-phase winding is used for charging and discharging, so as to expand the charging and discharging power and shorten the charging and discharging time. For the case that the target phase winding is a multi-phase winding, the working state of the target phase bridge arm corresponding to the multi-phase winding can also be controlled according to the above three principles, and the specific control method can be understood in combination with the above content, which will not be described herein again.

[0174] In some embodiments of the present disclosure, as shown in FIG. 16, a flowchart of a charging and discharging control method according to still another embodiment of the present disclosure is shown, wherein the charging and discharging control method further includes step S4, which is specifically as follows.

[0175] S4, as the current difference between the actual charging and discharging current and the target charging and discharging current becomes smaller and smaller during charging and discharging, the carrier frequency of the corresponding bridge arm shows an increasing trend, or as the voltage difference between the charging and discharging port and the battery becomes smaller and smaller during charging and discharging, the carrier frequency of the corresponding bridge arm shows a decreasing trend.

[0176] In the charging and discharging system, the system efficiency can be further improved by changing the load frequency of each bridge arm in the motor drive circuit, and the load frequency of the bridge arm of the charging and discharging system is changed according to at least one of the voltage difference between the battery and the DC charging and discharging port and the charging and discharging current. For example, in the small current charging and discharging state, a relatively high load frequency can be used for control, and in the large current charging and discharging state, a relatively low load frequency can be used for control. The load frequency is controlled according to the voltage difference between the battery and the DC charging and discharging port, and the larger the voltage difference, the higher the load frequency, which reduces the current ripple of the charging and discharging and improves the system efficiency. Specifically, in the small current charging and discharging state, the increase of the load frequency has little effect on the power device loss, so the load frequency can be changed according to the charging and discharging power, current and other parameters of the battery. The smaller the charging and discharging current and / or the charging and discharging power, the higher the load frequency, which can reduce the iron loss; as the charging and discharging current and / or the charging and discharging power increases, the bridge arm carrier frequency decreases, which can reduce the bridge arm loss, balance the motor iron loss, and maintain high charging and discharging efficiency in the process of small current charging and discharging.

[0177] In the above, in the process of small power charging and discharging of the battery in the boost charging and discharging mode or the boost current charging and discharging mode, the lead method in the hardware structure of the charging and discharging system and the control algorithm of the embodiment can be combined, different control switches are selected according to different charging and discharging currents, the needs of the inductance and overcurrent capacity of the charging and discharging circuit are met, and the needs of the phase current ripple and the needs of the charging and discharging system efficiency are met.

[0178] The charging and discharging control method according to the embodiment of the present disclosure can ensure the safety of charging and discharging and the efficiency of the charging and discharging system by using the method of motor single-phase winding charging and discharging combined with increasing the carrier frequency in the process of small current charging and discharging of the battery. Moreover, the system efficiency of small current charging and discharging is relatively high, and the heat generation of the charging and discharging system is relatively small, so that the loss of the charging and discharging system can be optimized. In addition, when the temperature of each device of the charging and discharging system is within the safe range, the oil pump, water pump, fan and air conditioning cooling system circuit used for heat dissipation of the charging and discharging system can be turned off. By controlling the oil pump, water pump, fan and air conditioning cooling system to be turned on when the temperature does not meet the allowable temperature of the device, and turned off when the temperature meets the allowable temperature of the device, the system efficiency of the charging and discharging can be further improved.

[0179] In some embodiments of the present disclosure, an electronic device 40 is also provided, as shown in FIG. 17, which is a block diagram of the electronic device 40 according to an embodiment of the present disclosure. The electronic device 40 includes at least one processor 401 and a memory 402 in communication with the at least one processor 401. The memory 402 stores a computer program executable by the at least one processor 401. The at least one processor 401 executes the computer program to implement the charging and discharging control method of any one of the above.

[0180] The electronic device 40 according to the embodiments of the present disclosure, when the computer program stored in the memory 402 is executed by the at least one processor 401, implements the charging and discharging control method of any one of the above, and can control as few windings as possible to be turned on under the requirements of different target charging and discharging modes and target charging and discharging currents, thereby increasing inductance, reducing ripple, reducing loss, meeting the requirements of the charging and discharging loop on inductance and overcurrent capacity, and meeting the requirements of phase current ripple and charging and discharging system efficiency, and especially for small-power charging and discharging working conditions, the efficiency of battery charging and discharging can be effectively improved.

[0181] In some embodiments of the present disclosure, an electric energy device 100 is also provided, as shown in FIG. 18, which is a block diagram of the electric energy device 100 according to an embodiment of the present disclosure. The electric energy device 100 includes a battery 20, a charging and discharging port 30, an electronic device 40 of the above embodiment, and a charging and discharging system 10 of any one of the above embodiments. The charging and discharging system 10 is connected with the battery 20 and the charging and discharging port 30, and the electronic device 40 is connected with the charging and discharging system 10.

[0182] The electric energy device 100 according to the embodiments of the present disclosure is based on the architecture of the battery 20, the charging and discharging port 30, the electronic device 40, and the charging and discharging system 10. During the charging and discharging process of the battery 20, the requirements of the charging and discharging loop on inductance and overcurrent capacity can be met, and the requirements of phase current ripple and charging and discharging system efficiency can also be met. Especially in the case of small-power charging and discharging working conditions of the electric energy device 100, the efficiency of the battery 20 charging and discharging can be effectively improved, so as to reduce the overall loss of the electric energy device 100 and improve the working efficiency of the electric energy device 100.

[0183] In some embodiments of the present disclosure, a non-transitory readable storage medium is also provided, and the computer program is stored on the non-transitory readable storage medium. When the computer program is executed, the charging and discharging control method of any one of the above is implemented.

[0184] The non-transitory readable storage medium according to the embodiments of the present disclosure implements the charging and discharging control method of any one of the above, and can control as few windings as possible to be turned on under the requirements of different target charging and discharging modes and target charging and discharging currents, thereby increasing inductance, reducing ripple, reducing loss, meeting the requirements of the charging and discharging loop on inductance and overcurrent capacity, and meeting the requirements of phase current ripple and charging and discharging system efficiency, and especially for small-power charging and discharging working conditions, the efficiency of battery charging and discharging can be effectively improved.

[0185] The other configurations and operations of the electric energy device 100 and the charging and discharging system 10 according to the embodiments of the present disclosure are known to those skilled in the art, and will not be described in detail here.

[0186] In the description of the disclosure, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the disclosure. In the description of the disclosure, the exemplary description of the above terms does not necessarily mean the same embodiment or example.

[0187] Although the embodiments of the disclosure have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the disclosure, and the scope of the disclosure is defined by the claims and their equivalents.

Claims

1. A charge-discharge system (10) characterized by, The system comprises: a motor drive circuit (1) comprising a plurality of bridge arms connected in parallel, each bridge arm being connected across a positive and a negative terminal of a battery (20), a first end of each bridge arm being further connected to a first end of a charge-discharge port (30); a motor (2) comprising a plurality of groups of windings, each group of windings comprising at least one set of windings, each set of windings comprising a plurality of phase windings, a first end of the phase windings in each set of windings being connected to a corresponding midpoint of the plurality of bridge arms, a second end of the phase windings in each set of windings being connected to a neutral terminal, the neutral terminals of each group of windings being connected together, a neutral terminal lead bundle of the plurality of groups of windings being connected to at least one of a second end of the charge-discharge port (30) and a positive terminal of the battery (20); and a plurality of control switches (K) disposed on the neutral terminal lead bundle, for switching according to a target charge-discharge mode and a target charge-discharge current, to control a corresponding number of the windings to form a charge-discharge loop. The plurality of groups of windings comprise different numbers of sets of windings, and the neutral terminals of each group of windings are connected to the second end of the charge-discharge port (30) through the control switches (K).

2. The charge and discharge system (10) according to claim 1, characterized by The neutral terminals of at least one of the plurality of groups of windings are further connected to the positive terminal of the battery (20).

3. The charge and discharge system (10) according to claim 2, characterized in that The motor (2) comprises a first group of windings and a second group of windings, the first group of windings comprising a smaller number of sets of windings than the second group of windings.

4. The charge and discharge system (10) according to claim 2 or 3, characterized by The plurality of control switches (K) comprise a first switch (K1) disposed between the neutral terminal of the first group of windings and the second end of the charge-discharge port (30), and a second switch (K2) disposed between the neutral terminal of the second group of windings and the second end of the charge-discharge port (30).

5. The charge and discharge system (10) according to claim 4, characterized in that 6. The charge-discharge system (10) according to claim 5, wherein: in a step-up charge-discharge mode, when the first group of windings satisfies the target charge-discharge current, the first switch (K1) is closed and the second switch (K2) is open; in the step-up charge-discharge mode, when the first group of windings does not satisfy the target charge-discharge current and the second group of windings satisfies the target charge-discharge current, the first switch (K1) is open and the second switch (K2) is closed; in the step-up charge-discharge mode, when the second group of windings does not satisfy the target charge-discharge current, both the first switch (K1) and the second switch (K2) are controlled to be closed. The neutral terminal of the first group of windings is connected to the positive terminal of the battery (20).

7. The charge and discharge system (10) according to any one of claims 4 to 6, characterized in that, The plurality of control switches (K) comprise a third switch (K3) disposed between the neutral terminal of the first group of windings and the positive terminal of the battery (20), for being closed in a step-up current charge-discharge mode.

8. The charge and discharge system (10) according to claim 7, characterized in that 9. The charge-discharge system (10) according to claim 8, wherein: the neutral terminal of the first group of windings is further connected to the neutral terminal of the second group of windings. ​ The plurality of control switches (K) further comprises a fourth switch (K4) disposed on a connection line between the neutral point of the first group of windings and the neutral point of the second group of windings, for closing when the first group of windings cannot meet the target charge-discharge current in the boost charge-discharge mode.

10. The charge and discharge system (10) according to any one of claims 4 to 9, characterized in that, The first group of windings comprises one set of windings, and the second group of windings comprises three sets of windings.

11. The charge and discharge system (10) according to claim 1, characterized by The neutral point of at least one group of windings in the plurality of groups of windings is connected to the second end of the charge-discharge port (30) through the control switch (K), and the neutral point of the winding other than the winding connected to the second end of the charge-discharge port (30) in the plurality of groups of windings is connected to the positive terminal of the battery (20) through the control switch (K).

12. The charge and discharge system (10) according to claim 11, characterized by In the boost charge-discharge mode, the control switch (K) disposed on the connection line between the neutral point and the second end of the charge-discharge port (30) is closed, or in the boost charge-discharge mode, the control switch (K) disposed on the connection line between the neutral point and the positive terminal of the battery (20) is closed.

13. The charge and discharge system (10) according to claim 11 or 12, characterized in that The plurality of groups of windings comprises windings with different numbers of sets.

14. The charge and discharge system (10) according to any one of claims 11-13, characterized by The plurality of groups of windings comprises windings with the same number of sets.

15. The charge and discharge system (10) according to claim 14, characterized by The motor comprises a third group of windings and a fourth group of windings, the third group of windings comprises the same number of sets of windings as the fourth group of windings; The neutral point of the third group of windings is connected to the second end of the charge-discharge port (30), and the neutral point of the fourth group of windings is connected to the positive terminal of the battery (20).

16. The charge-discharge system (10) according to claim 15, wherein the plurality of control switches (K) comprises: a fifth switch (K5) disposed on a connection line between the neutral point of the third group of windings and the second end of the charge-discharge port (30), for closing in the boost charge-discharge mode; and a sixth switch (K6) disposed on a connection line between the neutral point of the fourth group of windings and the positive terminal of the battery (20), for closing in the boost charge-discharge mode.

17. The charge-discharge system (10) according to claim 15 or 16, wherein: the neutral point of the third group of windings is connected to the neutral point of the fourth group of windings; the plurality of control switches (K) further comprises: a seventh switch (K7) disposed on a connection line between the neutral point of the third group of windings and the neutral point of the fourth group of windings, for closing when the third group of windings does not meet the target charge-discharge current in the boost charge-discharge mode, or for closing when the fourth group of windings does not meet the target charge-discharge current in the boost charge-discharge mode. The third group of windings comprises two sets of windings, and the fourth group of windings comprises two sets of windings.

18. The charge and discharge system (10) according to any one of claims 15-17, characterized by, The second end of the bridge arm of each phase is further connected to the second end of the charge-discharge port (30); 19. The charge and discharge system (10) according to any one of claims 2, 3, 11-17, characterized by, ​ The charging and discharging system (10) further comprises an eighth switch (K8) arranged on a connection line between the second end of the bridge arm and the second end of the charging and discharging port (30), and used for being closed in the direct charging and discharging mode or the boost charging and discharging mode.

20. The charge and discharge system (10) according to any one of claims 1 to 19, characterized by, The charging and discharging system (10) further comprises: a positive main contactor (K+) arranged on a connection line between the second end of the bridge arm of each phase and the positive end of the battery (20), and used for being closed in the direct charging and discharging mode or the boost charging and discharging mode; and a negative main contactor (K-) arranged on a connection line between the first end of the bridge arm of each phase and the negative end of the battery (20), and used for being closed in the direct charging and discharging mode or the boost charging and discharging mode.

21. The charge and discharge system (10) according to any one of claims 1 to 20, characterized by, The charging and discharging system (10) further comprises: a ninth switch (K9) arranged on a connection line between the first end of the charging and discharging port (30) and the first end of the bridge arm of each phase, and used for being closed in the direct charging and discharging mode or the boost charging and discharging mode or the boost charging mode.

22. The charge and discharge system (10) according to any one of claims 1 to 21, characterized by, The charging and discharging system (10) further comprises: a pre-charge unit (50) closed during charging and discharging.

23. A charge and discharge system (10) characterized by, Comprise: a motor drive circuit (1) comprising bridge arms connected in parallel in multiple phases, each of the bridge arms being connected across the positive and negative poles of a battery (20), and the first end of each of the bridge arms being further connected to the first end of a charging and discharging port (30); a motor (2) comprising multiple sets of windings, each set of windings comprising at least one set of windings, each set of windings comprising multiple phase windings, the first end of the multiple phase windings in each set of windings being connected to the midpoint of the multiple bridge arms in multiple phases, the second end of the multiple phase windings in each set of windings being connected together, and a wire harness being led between the first end of at least one phase winding in the multiple phase windings and the midpoint of the multiple bridge arms, the led wire harness being connected to at least one of the second end of the charging and discharging port (30) and the positive end of the battery (20); and a plurality of control switches (K) arranged on the led wire harness, and used for being switched according to a target charging and discharging mode to form a corresponding charging and discharging loop. The charging and discharging control method for the charging and discharging system of any one of claims 1-22 comprises:

24. A charge and discharge control method characterized by comprising: obtaining a target charging and discharging current; controlling the switching state of a plurality of control switches arranged on the led wire harness of the neutral point of the multiple sets of windings in the charging and discharging system according to the target charging and discharging current and a target charging and discharging mode, so as to control a corresponding number of windings to form a charging and discharging loop. The charging and discharging control method further comprises: controlling the switching state of the multiple phase bridge arms of the charging and discharging system according to the target charging and discharging current and the rotor position of the motor.

25. The charge and discharge control method according to claim 24, wherein Controlling the switching state of the multiple phase bridge arms of the charging and discharging system according to the target charging and discharging current and the rotor position of the motor comprises:

26. The charge and discharge control method according to claim 25, wherein ​ determining the number of winding phases required to form a charging and discharging circuit according to the target charging and discharging current; determining a target phase winding corresponding to the number of winding phases according to the rotor position of the motor, and controlling the switching state of the target phase winding corresponding to the target phase bridge arm.

27. The charge and discharge control method according to claim 26, wherein The target phase winding is a single-phase winding, which is the single-phase winding in the multi-phase winding that produces the torque with the smallest angle between the generated magnetic field and the magnetic field generated by the rotor, or, when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is the winding that produces the torque with the smallest angle between the generated superimposed magnetic field and the magnetic field generated by the rotor.

28. The charge and discharge control method according to claim 26, wherein The target phase winding is a single-phase winding, which is the single-phase winding in the multi-phase winding that produces the torque with the smallest angle between the generated magnetic field and the magnetic field generated by the rotor, or, when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is the winding that produces the torque with the smallest angle between the generated superimposed magnetic field and the magnetic field generated by the rotor.

29. The charge and discharge control method according to claim 26, wherein The target phase winding is a single-phase winding, which is the single-phase winding in the multi-phase winding that produces the torque with the smallest angle between the generated magnetic field and the magnetic field generated by the rotor, or, when the single-phase winding does not meet the target charging and discharging current, the target phase winding is a multi-phase winding, which is the winding that produces the torque with the smallest angle between the generated superimposed magnetic field and the magnetic field generated by the rotor.

30. The charge and discharge control method according to any one of claims 26-29, characterized by, When the target phase winding is a multi-phase winding, the multi-phase winding is controlled uniformly in different phases or in the same phase.

31. The charge and discharge control method according to any one of claims 26-30, characterized by, The charging and discharging control method further comprises: As the current difference between the actual charging and discharging current and the target charging and discharging current becomes smaller and smaller during charging and discharging, the carrier frequency of the corresponding bridge arm is controlled to increase, or as the voltage difference between the charging and discharging port and the battery becomes smaller and smaller during charging and discharging, the carrier frequency of the corresponding bridge arm is controlled to decrease.

32. The charge and discharge control method according to any one of claims 24-31, characterized by, The target charging and discharging current is the minimum current value among the first charging and discharging current, the second charging and discharging current, and the third charging and discharging current; The first charging and discharging current is obtained according to the motor winding temperature, the motor rotor temperature, and the power device temperature; The second charging and discharging current is obtained according to the battery SOC, the battery minimum voltage, the battery current voltage, the battery maximum voltage, and the battery temperature; The third charging and discharging current is obtained according to the charging pile current voltage platform, the charging gun charging and discharging state, and the charging gun charging and discharging power.

33. An electronic device (40), characterized by comprises: at least one processor (401); and a memory (402) connected in communication with the at least one processor (401); The memory (402) stores a computer program executable by the at least one processor (401), and the at least one processor (401) executes the computer program to implement the charging and discharging control method of any one of claims 24-32.

34. An electrical energy device (100) characterized by The electric energy device (100) comprises: a battery (20); a charging and discharging port (30); an electronic device (40) according to claim 33; and The charge-discharge system (10) according to any one of claims 1-23, wherein the charge-discharge system (10) is connected with the battery (20) and the charge-discharge port (30), and the electronic device (40) is connected with the charge-discharge system (10).

35. A non-transitory readable storage medium having stored thereon a computer program, wherein The computer program, when executed, implements the charge-discharge control method according to any one of claims 24-32.

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