Battery heating method, battery heating circuit and electric equipment

Abstract

The invention relates to a battery heating method, a battery heating circuit and electric equipment, and the method comprises the steps: obtaining a heating enabling signal which is used for indicating a motor to heat a battery based on a heating circuit, responding to the heating enabling signal, and controlling the on-off state of a switching tube in a switching circuit, therefore, the battery is heated under the condition that the current direction of the stator winding of each phase of the motor is kept unchanged, so that the current harmonic of the stator winding of the motor can be increased, and the vibration noise energy of the motor in the battery heating process can be dispersed. Therefore, compared with the traditional technology, the vibration noise of the motor in the battery heating process is relatively low, so that the vibration noise problem of the motor in the battery heating process can be improved.

Description

Battery heating method, battery heating circuit and electric device

[0001] Cross-references

[0002] This application refers to PCT International Application No. PCT / CN2023 / 070256 filed on January 4, 2023, entitled “Battery Heating Method, Battery Heating Circuit and Electrical Equipment”, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of motor technology, and in particular to a battery heating method, a battery heating circuit, and an electrical device. Background Art

[0004] With the rapid development of new energy technologies, more and more new energy electrical devices are being used. During the use of these devices, it is sometimes necessary to control the motor to heat the battery, but the heating process is quite noisy.

[0005] Traditionally, adding a neutral point in the motor has been used to reduce the high vibration and noise associated with motor pulse heating. However, even with traditional technology, adding a neutral point in the motor still produces high vibration and noise during battery heating.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides a battery heating method, a battery heating circuit and an electrical device, which can solve the problem of relatively large vibration noise during the battery heating process of the motor in traditional technology.

[0008] In a first aspect, the present application provides a battery heating method, the method comprising:

[0009] Obtaining a heating enable signal, wherein the heating enable signal is used to instruct the motor to heat the battery based on a heating circuit, the heating circuit including the motor and a switching circuit respectively connected to the motor and the battery;

[0010] In response to the heating enable signal, the on-off state of the switch tube in the switch circuit is controlled to heat the battery while the current direction of the stator winding of each phase of the motor remains unchanged.

[0011] In the technical solution of the embodiment of the present application, a heating enable signal is obtained to instruct the motor to heat the battery based on the heating circuit. In response to the heating enable signal, the on / off state of the switch tube in the switching circuit is controlled. This allows the motor to heat the battery while maintaining the current direction of each phase of the stator winding unchanged. This increases the harmonics of the motor's stator winding current, thereby dissipating the vibration and noise energy generated by the motor heating the battery. As can be seen, compared to conventional technologies, the vibration and noise generated by the motor heating the battery in the embodiment of the present application is smaller, thereby improving the vibration and noise problem during the motor heating the battery.

[0012] In some embodiments, the current of each phase stator winding changes periodically, and the current cycle of each phase stator winding includes: a stator winding energy storage stage where the current gradually increases, a stator winding freewheeling stage where the current remains unchanged, a stator winding discharge stage where the current gradually decreases, and a stator winding current gap stage where the current is zero.

[0013] In the technical solution of the embodiment of the present application, the current of each phase stator winding changes periodically, and the current cycle of each phase stator winding includes: a stator winding energy storage stage in which the current gradually increases, a stator winding freewheeling stage in which the current remains unchanged, a stator winding discharge stage in which the current gradually decreases, and a stator winding current gap stage in which the current is zero. That is, the current direction of each phase stator winding remains unchanged during the battery heating process of the motor in the embodiment of the present application, thereby increasing the stator winding current harmonics of the motor so as to disperse the vibration noise energy of the motor during the battery heating process. In addition, in the embodiment of the present application, by controlling the gap duration of the motor in the stator winding current gap stage, the effective value of the stator winding current can be reduced while keeping the effective value of the battery current waveform unchanged, thereby further reducing the motor noise.

[0014] In some embodiments, during the stator winding current gap phase, where the current is zero, the battery is charged by a capacitor in the heating circuit, where the capacitor is connected in series across the battery. The technical solutions of the embodiments of the present application not only ensure battery heating efficiency but also improve energy utilization during the battery heating process.

[0015] In some embodiments, the current in each phase of the stator winding is a half-wave current, meaning that the direction of the current in each phase of the stator winding does not change within each half-cycle. The technical solutions of the embodiments of the present application not only increase the harmonics of the motor's stator winding current, thereby dissipating the vibration and noise energy generated by the motor heating the battery, but also increase the heating time and power, thereby improving battery heating efficiency.

[0016] In some embodiments, when the motor is in the stator winding discharge stage, the lower arm switch tube in the first inverter bridge arm in the switching circuit is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electric energy stored in the motor to the battery, so as to facilitate heating the battery; wherein, the first inverter bridge arm is the bridge arm in which the lower arm switch tube in the switching circuit is in the on state when the motor is in the stator winding energy storage stage.

[0017] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit is in the on state, forming a discharge path for the battery to transmit the electrical energy stored in the battery to the motor, so as to facilitate heating of the battery.

[0018] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state to disconnect the battery from the discharge path of the motor.

[0019] In some embodiments, when the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the first inverter bridge arm continues to be in the disconnected state, forming an energy oscillation path between the capacitor in the heating circuit and the battery, so that the capacitor in the heating circuit will oscillate with the battery, thereby improving the energy utilization during the battery heating process.

[0020] In summary, when the motor is in different stages, the on-off states of the switching tubes in the three inverter bridge arms in the switching circuit are different, so that the current direction of each phase stator winding remains unchanged during the battery heating process of the motor, so as to increase the stator winding current harmonics of the motor and disperse the vibration noise energy of the battery heating process of the motor, thereby improving the vibration noise problem during the battery heating process of the motor.

[0021] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch circuit includes:

[0022] The upper bridge arm switch tube of the second inverter bridge arm in the control switching circuit is in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit are in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0023] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch circuit includes:

[0024] When it is detected that the operating state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0025] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch circuit includes:

[0026] When it is detected that the time of the freewheeling phase exceeds the preset freewheeling time, the lower bridge arm switch tube in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge stage.

[0027] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch circuit includes:

[0028] After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch tube in the first inverter bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery in the heating circuit, so that the motor is in the stator winding current gap stage.

[0029] In summary, by controlling the on / off states of the upper arm switch tube of the second inverter bridge arm and the lower arm switch tube of the first inverter bridge arm among the three inverter bridge arms in the switching circuit, the motor can heat the battery while keeping the current direction of each phase stator winding unchanged, so as to increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor heating the battery. In addition, the controller can also control the gap length of the motor in the stator winding current gap state, thereby reducing the effective value of the stator winding current while keeping the effective value of the battery current waveform unchanged, thereby further reducing the motor noise. Therefore, compared with traditional technologies, the embodiments of the present application can effectively improve the motor noise while ensuring that the original battery heating effect remains unchanged.

[0030] In some embodiments, before controlling the upper-bridge-arm switch tube of the second inverter bridge arm in the switch circuit to be in the on state and the lower-bridge-arm switch tubes in the first inverter bridge arm other than the second inverter bridge arm in the switch circuit to be in the on state, the method further includes:

[0031] The second inverter bridge arm is determined according to the rotor position of the motor.

[0032] In some embodiments, determining the second inverter bridge arm according to the rotor position of the motor includes:

[0033] Acquiring space vector data, where the switch state space vector data includes a plurality of space sectors, wherein each space sector corresponds to different switch state information;

[0034] Determine a first spatial sector in which a rotor of the motor is located, and a second spatial sector symmetrical to the first spatial sector;

[0035] The second inverter bridge arm is determined according to the switch state information corresponding to the first spatial sector and the second spatial sector.

[0036] In the technical solution of the embodiment of the present application, by determining the second inverter bridge arm of the upper bridge arm switch tube that needs to be turned on among the three inverter bridge arms in the appropriate switching circuit according to the rotor position of the motor, so that the angle between the magnetic field generated by the stator magnetic field and the magnetic field of the rotor during inductive excitation is smaller, thereby making the torque fluctuation generated at the beginning of heating smaller.

[0037] In some embodiments, when the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm in the switching circuit is switched to the disconnected state; or, the upper arm switch tube in the neutral bridge arm is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electrical energy stored in the motor to the battery, so as to facilitate heating the battery.

[0038] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state; or, the lower arm switch tube in each inverter bridge arm is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor, so as to facilitate heating the battery.

[0039] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube in each inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the neutral bridge arm continues to be in the on state; or, the lower arm switch tube in each inverter bridge arm is switched to the disconnected state, and the upper arm switch tube in the neutral bridge arm continues to be in the on state, so as to disconnect the battery from the discharge path of the motor.

[0040] In some embodiments, when the motor is in the stator winding current gap stage, the lower arm switch tube in the neutral bridge arm continues to be in the disconnected state; or, the upper arm switch tube in the neutral bridge arm continues to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the capacitor in the heating circuit will oscillate with the battery, thereby improving the energy utilization during the battery heating process.

[0041] In summary, when the motor is in different stages, the on-off states of the switching tubes in the three inverter bridge arms and the neutral bridge arm are different, so that the current direction of each phase stator winding remains unchanged during the battery heating process of the motor, so as to increase the stator winding current harmonics of the motor and disperse the vibration noise energy of the battery heating process of the motor, thereby improving the vibration noise problem during the battery heating process of the motor.

[0042] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch tube circuit includes:

[0043] Control the upper bridge arm switch tubes in each inverter bridge arm to be in the on state, and the lower bridge arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to the motor, so that the motor is in the stator winding energy storage stage; or

[0044] The lower bridge arm switch tubes in each inverter bridge arm are controlled to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm are controlled to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0045] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch tube circuit includes:

[0046] When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage; or

[0047] When it is detected that the operating state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0048] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch tube circuit includes:

[0049] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge phase; or

[0050] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

[0051] In some embodiments, in response to the heating enable signal, controlling the on / off state of a switch tube in the switch tube circuit includes:

[0052] After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage; or

[0053] After detecting that the energy stored in the stator winding of the motor has been released, the upper arm switch tube in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

[0054] In some embodiments, obtaining a heating enable signal includes:

[0055] When it is detected that the battery heating condition is met and the motor is in a non-operating state, a heating enable signal is generated; or,

[0056] Receive a heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

[0057] In some embodiments, the method further comprises:

[0058] When it is detected that the battery temperature is abnormal or the battery temperature reaches a preset temperature, the switch tube in the control switch circuit is in the disconnected state.

[0059] In some embodiments, the method further comprises:

[0060] When a battery temperature abnormality signal or a heating stop enable signal is received from the vehicle controller, the switch tube in the control switch circuit is in the disconnected state.

[0061] In a second aspect, the present application provides a battery heating circuit, the battery heating circuit comprising: a heating circuit and a controller, wherein the heating circuit comprises a motor and a switching circuit respectively connected to the motor and the battery;

[0062] The controller is used to control the on-off state of the switching tube in the switching circuit in response to the heating enable signal after obtaining the heating enable signal, so as to heat the battery while maintaining the current direction of each phase stator winding of the motor unchanged, wherein the heating enable signal is used to instruct the motor to heat the battery based on the heating circuit.

[0063] In some embodiments, the current of each phase stator winding changes periodically, and the current cycle of each phase stator winding includes: a stator winding energy storage stage where the current gradually increases, a stator winding freewheeling stage where the current remains unchanged, a stator winding discharge stage where the current gradually decreases, and a stator winding current gap stage where the current is zero.

[0064] In some embodiments, the battery is charged by a capacitor in the heating circuit during a stator winding current gap phase where the current is zero, wherein the capacitor is connected in series across the battery.

[0065] In some embodiments, the current of each phase stator winding is a half-wave current.

[0066] In some embodiments, the switching circuit includes three inverter bridge arms disposed between the three-phase stator winding of the motor and the battery, and capacitors connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm is connected to the positive electrode of the battery, the second end of each inverter bridge arm is connected to the negative electrode of the battery, and the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor; each inverter bridge arm includes: an upper bridge arm switching tube and a lower bridge arm switching tube;

[0067] When the motor is in the stator winding discharge stage, the lower bridge arm switch tube in the first inverter bridge arm in the switching circuit is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electric energy stored in the motor to the battery; wherein, the first inverter bridge arm is the bridge arm in which the lower bridge arm switch tube in the switching circuit is in the on state when the motor is in the stator winding energy storage stage.

[0068] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

[0069] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state to disconnect the battery from the discharge path of the motor.

[0070] In some embodiments, when the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the first inverter bridge arm continues to be in an off state, forming an energy oscillation path between the capacitor in the heating circuit and the battery.

[0071] In some embodiments, the controller is specifically configured to:

[0072] The upper bridge arm switch tube of the second inverter bridge arm in the control switching circuit is in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit are in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0073] In some embodiments, the controller is specifically configured to:

[0074] When it is detected that the operating state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0075] In some embodiments, the controller is specifically configured to:

[0076] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to serve as the battery, so that the motor is in the stator winding discharge phase to heat the battery.

[0077] In some embodiments, the controller is specifically configured to:

[0078] After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch tube in the first inverter bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery in the heating circuit, so that the motor is in the stator winding current gap stage.

[0079] In some embodiments, the controller is further configured to:

[0080] The second inverter bridge arm is determined according to the rotor position of the motor.

[0081] In some embodiments, the controller is specifically configured to:

[0082] Acquiring space vector data, where the switch state space vector data includes a plurality of space sectors, wherein each space sector corresponds to different switch state information;

[0083] Determine a first spatial sector in which a rotor of the motor is located, and a second spatial sector symmetrical to the first spatial sector;

[0084] The second inverter bridge arm is determined according to the switch state information corresponding to the first spatial sector and the second spatial sector.

[0085] In some embodiments, the switching circuit includes: a neutral bridge arm arranged between the neutral line of the motor and the battery, three inverter bridge arms arranged between the three-phase stator winding of the motor and the battery, and a capacitor connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm and the first end of the neutral bridge arm are connected to the positive electrode of the battery, the second end of each inverter bridge arm and the second end of the neutral bridge arm are connected to the negative electrode of the battery, the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor, and the third end of the neutral bridge arm is connected to the neutral line of the motor; each inverter bridge arm includes: an upper bridge arm switching tube and a lower bridge arm switching tube, and the neutral bridge arm includes an upper bridge arm switching tube and a lower bridge arm switching tube;

[0086] When the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm in the switching circuit is switched to the off state; or, the upper arm switch tube in the neutral bridge arm is switched to the off state, forming a charging path for the motor to transfer the electrical energy stored in the motor to the battery.

[0087] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state; or, the lower arm switch tube in each inverter bridge arm is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

[0088] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube in each inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the neutral bridge arm continues to be in the on state; or, the lower arm switch tube in each inverter bridge arm is switched to the disconnected state, and the upper arm switch tube in the neutral bridge arm continues to be in the on state, so as to disconnect the battery from the discharge path of the motor.

[0089] In some embodiments, when the motor is in the stator winding current gap stage, the lower arm switch tube in the neutral bridge arm continues to be in the disconnected state; or, the upper arm switch tube in the neutral bridge arm continues to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery.

[0090] In some embodiments, the controller is specifically configured to:

[0091] Control the upper bridge arm switch tubes in each inverter bridge arm to be in the on state, and the lower bridge arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to the motor, so that the motor is in the stator winding energy storage stage; or

[0092] The lower bridge arm switch tubes in each inverter bridge arm are controlled to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm are controlled to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0093] In some embodiments, the controller is specifically configured to:

[0094] When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage; or

[0095] When it is detected that the operating state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0096] In some embodiments, the controller is specifically configured to:

[0097] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge phase; or

[0098] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

[0099] In some embodiments, the controller is specifically configured to:

[0100] After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage; or

[0101] After detecting that the energy stored in the stator winding of the motor has been released, the upper arm switch tube in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

[0102] In some embodiments, the switch tube in the switch circuit includes: an insulated gate bipolar transistor (IGBT) or a silicon carbide transistor.

[0103] In some embodiments, the controller is specifically configured to:

[0104] When it is detected that the battery heating condition is met and the motor is in a non-operating state, a heating enable signal is generated; or,

[0105] Receive a heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

[0106] In some embodiments, the controller is further configured to:

[0107] When the battery temperature is detected to be abnormal or the battery temperature reaches a preset temperature, the switch tube in the switch circuit is controlled to be in an off state; or,

[0108] When a battery temperature abnormality signal or a heating stop enable signal is received from the vehicle controller, the switch tube in the control switch circuit is in the disconnected state.

[0109] In a third aspect, the present application provides an electrical device, which includes the battery heating circuit of any embodiment of the second aspect.

[0110] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0112] FIG1A is a schematic diagram of an application environment provided by an embodiment of the present application;

[0113] FIG1B is a second schematic diagram of an application environment provided by an embodiment of the present application;

[0114] FIG2 is a schematic flow chart of a battery heating method provided in some embodiments of the present application;

[0115] FIG3 is a schematic diagram of current waveforms of stator windings provided in some other embodiments of the present application;

[0116] FIG4 is a schematic structural diagram of a battery heating circuit provided in some embodiments of the present application;

[0117] FIG5 is a schematic diagram of a space vector diagram provided in an embodiment of the present application;

[0118] FIG6 is a first schematic diagram of current flow when the motor provided by an embodiment of the present application is in the stator winding energy storage stage;

[0119] FIG7 is a first schematic diagram of current flow of a motor provided by an embodiment of the present application when the motor is in the stator winding freewheeling stage;

[0120] FIG8 is a first schematic diagram of current flow when the motor provided by an embodiment of the present application is in the stator winding discharge stage;

[0121] FIG9 is a schematic flow chart of a battery heating method provided in some other embodiments of the present application;

[0122] FIG10 is a schematic structural diagram of a battery heating circuit provided in other embodiments of the present application;

[0123] FIG11 is a second schematic diagram of current flow when the motor provided by an embodiment of the present application is in the stator winding energy storage stage;

[0124] FIG12 is a second schematic diagram of current flow when the motor provided by an embodiment of the present application is in the stator winding freewheeling stage;

[0125] FIG13 is a second schematic diagram of current flow when the motor provided by an embodiment of the present application is in the stator winding discharge stage;

[0126] FIG14 is a schematic flow chart of a battery heating method provided in some other embodiments of the present application;

[0127] FIG15 is a schematic flow chart of a battery heating method provided in some other embodiments of the present application;

[0128] FIG16 is a schematic structural diagram of a battery heating circuit provided in some other embodiments of the present application. DETAILED DESCRIPTION

[0129] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0130] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the term "include" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0131] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is two or more (including two), unless otherwise clearly and specifically defined.

[0132] Traditionally, adding a neutral point to the motor has been used to reduce the high vibration and noise associated with motor pulse heating. However, even with this method, the motor still generates high vibration and noise during battery heating.

[0133] In order to reduce the vibration noise during the battery heating process of the motor, the applicant has found that the vibration noise energy during the battery heating process of the motor can be dispersed by increasing the harmonics of the stator winding current of the motor, thereby reducing the sound pressure level of the vibration noise.

[0134] Based on the above considerations, and to address the vibration noise issues associated with conventional battery heating by motors, the applicant has proposed a battery heating method. By controlling the on / off states of the switching transistors in a switching circuit connected to the motor, the method heats the battery while maintaining the direction of the current flowing through each phase of the stator windings. This increases the harmonics of the motor's stator winding current, thereby dissipating the energy of the vibration noise associated with the battery heating process. As can be seen, compared to conventional technologies, the vibration noise associated with the battery heating process in the embodiments of the present application is lower.

[0135] FIG1A is a schematic diagram of an application environment provided by an embodiment of the present application. As shown in FIG1A , the application environment of the embodiment of the present application may include, but is not limited to, a battery 101, a switching circuit 102, a motor 103, a motor controller 104, a battery management system (BMS) 105, and a vehicle controller 106. For example, the motor controller 104 may include, but is not limited to, a motor control unit (MCU).

[0136] For example, when the BMS 105 detects that the battery 101 needs to be heated, it sends a heating request to the vehicle controller 106, so that the vehicle controller 106 instructs the motor controller 104 to control the motor 103 to heat the battery 101. The motor controller 104 is configured to control the on / off state of the switch in the switch circuit 102 according to the battery heating method provided in the embodiment of the present application to control the motor 103 to heat the battery 101.

[0137] FIG1B is a second schematic diagram of an application environment provided by an embodiment of the present application. As shown in FIG1B , the application environment of the embodiment of the present application may include, but is not limited to, a battery 101, a switching circuit 102, a motor 103, and a domain controller 107. The domain controller 107 may integrate the functions of a motor controller, a BMS, and a vehicle controller.

[0138] For example, when the domain controller 107 detects that the battery 101 needs to be heated, it controls the motor 103 to heat the battery 101. The domain controller 107 is configured to control the on / off state of the switch in the switch circuit 102 according to the battery heating method provided in the embodiment of the present application to control the motor 103 to heat the battery 101.

[0139] Any switch tube involved in the embodiments of the present application may include an insulated gate bipolar transistor (IGBT) or a silicon carbide transistor; of course, other controllable switch tubes may also be included, which is not limited in the embodiments of the present application. It should be noted that any switch tube involved in the embodiments of the present application is a switch tube including a body diode.

[0140] In some embodiments, FIG2 is a flow chart of a battery heating method provided in some embodiments of the present application. In the embodiments of the present application, the method is described by applying it to a controller as an example, wherein the controller may be the motor controller 104 in FIG1A or the domain controller 107 in FIG1B . As shown in FIG2 , the method of the embodiment of the present application may include the following steps:

[0141] Step S201: Acquire a heating enable signal.

[0142] The heating circuit involved in the embodiments of the present application may include but is not limited to a motor and a switching circuit connected to the motor and the battery respectively, wherein the switching circuit is used to adjust the current path between the battery and the motor under the control of a controller so as to heat the battery while the motor maintains the current direction of each phase stator winding unchanged.

[0143] Optionally, the switching circuit may include multiple bridge arms disposed between the motor and the battery, wherein each bridge arm may include an upper bridge arm switching transistor and a lower bridge arm switching transistor. The different on / off states of the switching transistors in each bridge arm of the switching circuit may adjust the current path between the battery and the motor.

[0144] In one possible implementation, if the motor includes a three-phase stator winding (excluding the neutral line), the switching circuit may include three inverter bridge arms arranged between the three-phase stator winding of the motor and the battery, and capacitors connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm is connected to the positive pole of the battery, the second end of each inverter bridge arm is connected to the negative pole of the battery, and the third ends of the three inverter bridge arms are respectively connected one-to-one with the three-phase stator winding of the motor; the capacitor is connected in series at both ends of the battery, and the capacitor has a voltage stabilization function, a filtering function and / or an energy storage function. Of course, other devices may also be included in the switching circuit, which is not limited in the embodiments of the present application. It should be understood that each inverter bridge arm in the embodiments of the present application includes multiple switching tubes.

[0145] In another possible implementation, if the motor includes a three-phase stator winding and a neutral line, the switching circuit may include a neutral bridge arm arranged between the neutral line of the motor and the battery, three inverter bridge arms arranged between the three-phase stator winding of the motor and the battery, and a capacitor connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm and the first end of the neutral bridge arm are connected to the positive pole of the battery, the second end of each inverter bridge arm and the second end of the neutral bridge arm are connected to the negative pole of the battery, the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor, and the third end of the neutral bridge arm is connected to the neutral line of the motor; the capacitor is connected in series at both ends of the battery, and the capacitor has a voltage stabilization function, a filtering function and / or an energy storage function; of course, other devices may also be included in the switching circuit, which is not limited in the embodiment of the present application. It should be understood that each inverter bridge arm and each neutral bridge arm in the embodiment of the present application may respectively include multiple switching tubes.

[0146] In this step, the controller may obtain a heating enable signal, wherein the heating enable signal is used to instruct the motor to heat the battery based on the heating circuit.

[0147] In one possible implementation, if the controller is a motor controller, the controller can receive a heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

[0148] Exemplarily, the BMS can collect the status parameters of the battery in real time, wherein the status parameters may include but are not limited to: temperature, state of charge (SOC), voltage and current. Further, the BMS can determine whether the battery heating condition 1 is met based on the battery temperature and / or SOC; if the battery heating condition 1 is met, the BMS can send a heating request to the vehicle controller, wherein meeting the battery heating condition 1 may include but is not limited to: the battery temperature is lower than the preset temperature lower limit, and / or the SOC is in the preset SOC range. Further, after receiving the heating request sent by the BMS, the vehicle controller can detect the status of the motor; if it is detected that the motor is in a non-working state, the vehicle controller can send a heating enable signal to the controller. It should be understood that the heating enable signal involved in the embodiment of the present application can be sent by the vehicle controller through various communication protocols or signaling, and this is not limited in the embodiment of the present application.

[0149] Of course, the heating enable signal can also be sent to the controller by the vehicle controller in other situations. For example, the heating enable signal can also be sent to the controller by the vehicle controller when it detects that the preset time has been reached or the ambient temperature is lower than the preset ambient temperature and the motor is in a non-working state.

[0150] It should be noted that if it is detected that the motor is in a working state (or called a driving state), the vehicle controller can send a control drive signal to the controller so that the controller sends a periodic drive signal to control the on and off state of the switch tubes in each inverter bridge arm, thereby realizing the inverter control of the battery current.

[0151] In another possible implementation, if the controller is a domain controller, the controller can generate a heating enable signal when it detects that battery heating condition 2 is met and the motor is in a non-working state, wherein battery heating condition 2 may include but is not limited to: the battery temperature is lower than a preset temperature lower limit, the SOC is in a preset SOC range, a preset time is reached, and / or the ambient temperature is lower than a preset ambient temperature.

[0152] Of course, the controller can also obtain the heating enable signal in other ways, which is not limited in the embodiments of the present application.

[0153] Step S202 : In response to the heating enable signal, controlling the on / off state of the switch tube in the switch circuit so as to heat the battery while keeping the current direction of each phase stator winding of the motor unchanged.

[0154] In this step, the controller can respond to the heating enable signal obtained in the above step S201 to control the on-off state of the switch tube in the switching circuit, and adjust the current path between the battery and the motor so that the battery can be heated while the current direction of each phase stator winding of the motor remains unchanged, so as to increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor in the process of heating the battery.

[0155] For example, the current of each phase stator winding in the embodiment of the present application can be a half-wave current, that is, the current direction of each phase stator winding does not change within each half cycle. This can not only increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor in the battery heating process, but also increase the heating time and heating power, which is beneficial to increase the battery heating efficiency.

[0156] As another example, the current of each phase stator winding in the embodiment of the present application can be a quarter-wavelength current, that is, the current direction of each phase stator winding does not change within each quarter cycle. Of course, the current of each phase stator winding in the embodiment of the present application can also be other forms of current.

[0157] In one possible implementation, if the motor includes a three-phase stator winding (excluding the neutral line), the controller can control the on-off state of the switching tubes in the three inverter bridge arms in the switching circuit in response to the heating enable signal, so as to heat the battery while the motor maintains the current direction of each phase stator winding unchanged.

[0158] In another possible implementation, if the motor includes a three-phase stator winding and a neutral line, the controller can control the on-off state of the switching tubes in the three inverter bridge arms and the neutral bridge arm in the switching circuit in response to the heating enable signal, so as to heat the battery while the motor maintains the current direction of each phase stator winding unchanged.

[0159] The battery heating method described above obtains a heating enable signal that instructs the motor to heat the battery using the heating circuit. In response to the heating enable signal, it controls the on / off state of the switch in the switching circuit, allowing the motor to heat the battery while maintaining the direction of the current in each phase of the stator winding. This increases the harmonics of the motor's stator winding current, thereby dissipating the vibration and noise energy generated by the motor heating the battery. As can be seen, compared to conventional technologies, the vibration and noise generated by the motor heating the battery in the embodiments of the present application are lower, thereby improving the vibration and noise issues associated with the motor heating the battery.

[0160] In some embodiments, based on the above embodiments, the embodiments of the present application introduce relevant contents of the current of each phase stator winding.

[0161] In some embodiments, the current of each phase stator winding can change periodically, and the current cycle of each phase stator winding may include but is not limited to: a stator winding energy storage stage where the current gradually increases, a stator winding freewheeling stage where the current remains unchanged, a stator winding discharge stage where the current gradually decreases, and a stator winding current gap stage where the current is zero.

[0162] For ease of understanding, in the embodiments of the present application, the current waveform of the stator winding of each phase is exemplified by taking the current of the stator winding of each phase as a half-wave current. Figure 3 is a schematic diagram of the current waveform of the stator winding of any phase provided in other embodiments of the present application. As shown in Figure 3, the current of the stator winding of any phase in the embodiment of the present application changes periodically, and the current cycle of the stator winding of this phase may include: a stator winding energy storage stage S1 in which the current gradually increases, a stator winding freewheeling stage S2 in which the current remains unchanged, a stator winding discharge stage S3 in which the current gradually decreases, and a stator winding current gap stage S4 in which the current is zero.

[0163] Exemplarily, when the current of the stator winding is in the stator winding energy storage stage S1 where the current gradually increases, the battery is in a discharging state, and the stator winding of the motor is in an excitation energy storage state (or referred to as the motor being in the stator winding energy storage stage); when the current of the stator winding is in the stator winding freewheeling stage S2 where the current remains unchanged, the stator winding of the motor is in an internal freewheeling state (or referred to as the motor being in the stator winding freewheeling stage); when the current of the stator winding is in the stator winding discharge stage S3 where the current gradually decreases, the stator winding of the motor is in an energy release and discharge state (or referred to as the motor being in the stator winding discharge stage), and the battery is in a charging state; when the current of the stator winding is in the stator winding current gap stage S4 where the current is zero, the stator winding of the motor is in a gap state (or referred to as the motor being in the stator winding current gap stage).

[0164] It should be understood that since the capacitor in the heating circuit stores some energy in the three stages before the stator winding current gap stage, when the current of the stator winding is in the stator winding current gap stage where the current is zero, the capacitor in the heating circuit can charge the battery, which not only ensures the heating efficiency of the battery, but also improves the energy utilization rate during the battery heating process.

[0165] It can be seen that the current of each phase stator winding in the embodiment of the present application changes periodically, and the current cycle of each phase stator winding includes: a stator winding energy storage stage in which the current gradually increases, a stator winding freewheeling stage in which the current remains unchanged, a stator winding discharge stage in which the current gradually decreases, and a stator winding current gap stage in which the current is zero. That is, the current direction of each phase stator winding remains unchanged during the battery heating process of the motor in the embodiment of the present application, thereby increasing the stator winding current harmonics of the motor, so as to disperse the vibration noise energy of the motor during the battery heating process.

[0166] In addition, in an embodiment of the present application, the controller can control the gap duration of the motor in the stator winding current gap stage (or the gap duration of the stator winding current in the stator winding current gap stage S4 where the current is zero), thereby reducing the effective value of the stator winding current while keeping the effective value of the battery current unchanged, thereby further reducing the motor noise.

[0167] In some embodiments, based on the above embodiments, the controller can also control the switch tube in the switch circuit to be in the disconnected state when it detects that the conditions for stopping heating are met, so that the motor stops heating the battery, which is beneficial to protecting the safety of the battery.

[0168] In one possible implementation, if the controller is a motor controller, the controller can control the switch tube in the switching circuit to be in the disconnected state when it receives a battery temperature abnormality signal or a heating stop enable signal sent by the vehicle controller, so that the motor stops heating the battery, which is beneficial to protecting the safety of the battery.

[0169] For example, the BMS can determine whether the battery temperature is abnormal in real time or at preset intervals; if it is determined that the battery temperature is abnormal, the BMS can send a battery temperature abnormality signal to the vehicle controller, so that the vehicle controller forwards the battery temperature abnormality signal to the controller, so that the controller controls the switch tube in the switch circuit to be in the disconnected state, thereby stopping heating the battery.

[0170] As another example, the BMS can determine whether the battery temperature reaches a preset temperature in real time or at preset intervals; if it is determined that the battery temperature reaches the preset temperature, the BMS can send a stop heating enable signal to the vehicle controller, so that the vehicle controller forwards the stop heating enable signal to the controller, so that the controller controls the switch tube in the switch circuit to be in the disconnected state, thereby stopping heating the battery.

[0171] In another possible implementation, if the controller is a domain controller, the controller can control the switch tube in the switching circuit to be in the disconnected state when it detects that the battery temperature is abnormal or the battery temperature reaches a preset temperature, so that the motor stops heating the battery, which is beneficial to protecting the safety of the battery.

[0172] It should be understood that if the controller does not detect that the heating stop condition is met during the execution of the above step S202, the above step S202 will continue to be executed.

[0173] Based on the above embodiments, the following embodiments of the present application will respectively introduce the case where the motor includes a three-phase stator winding (excluding a neutral line) and the case where the motor includes a three-phase stator winding and a neutral line.

[0174] In some embodiments, the present application describes a case where the motor includes a three-phase stator winding (excluding a neutral line). To facilitate understanding, the structure of the battery heating circuit is first described in the present application. Figure 4 is a schematic diagram of the structure of the battery heating circuit provided in some embodiments of the present application. As shown in Figure 4, the battery heating circuit of the present application embodiment may include: a heating circuit and a controller (not shown in Figure 4), wherein the heating circuit may include: a motor 103 and a switch circuit 102 connected to the motor 103 and the battery 101, respectively.

[0175] Exemplarily, the switching circuit 102 may include three inverter bridge arms (e.g., BA1, BA2, and BA3 in FIG. 4 ) disposed between the three-phase stator windings of the motor 103 (e.g., A, B, and C in FIG. 4 ) and the battery 101, and a capacitor C connected in parallel with the three inverter bridge arms. The first end of each inverter bridge arm is connected to the positive electrode of the battery 101, the second end of each inverter bridge arm is connected to the negative electrode of the battery 101, and the third ends of the three inverter bridge arms are connected one-to-one with the three-phase stator windings of the motor 103. Each inverter bridge arm may include an upper arm switch tube and a lower arm switch tube, for example, as shown in FIG. 4 , the inverter bridge arm BA1 includes an upper arm switch tube V1 and a lower arm switch tube V4, the inverter bridge arm BA2 includes an upper arm switch tube V2 and a lower arm switch tube V5, and the inverter bridge arm BA3 includes an upper arm switch tube V3 and a lower arm switch tube V6.

[0176] It should be noted that any switching tube in the embodiments of the present application can be a switching tube including a body diode. For example, diode D1 in Figure 4 is the body diode of switching tube V1, diode D2 is the body diode of switching tube V2,..., diode D6 is the body diode of switching tube V6.

[0177] It should be understood that the control terminal of each switching transistor in the embodiment of the present application is connected to a controller (not shown in FIG. 4 ), so that the controller can send a control signal to the corresponding switching transistor via the control terminal (e.g., the gate) of any switching transistor to control the on / off state of the corresponding switching transistor. For example, the control signal sent by the controller to any switching transistor may include, but is not limited to, a pulse width modulation (PWM) signal.

[0178] In the following embodiments of the present application, the on-off states of the switching tubes in the three inverter bridge arms in the switching circuit when the motor is in different stages are introduced.

[0179] 1) When the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit is in the on state, forming a discharge path for the battery to the motor, so that the battery discharges the motor and transfers the electrical energy stored in the battery to the motor. The stator winding of the motor is in the excitation energy storage state (that is, the stator inductance of the motor is in an energy accumulation and rising state), so that the current of each phase stator winding of the motor is in the stator winding energy storage stage where the current gradually increases.

[0180] In an embodiment of the present application, the controller can determine in advance the second inverter bridge arm of the three inverter bridge arms in the switching circuit whose upper bridge arm switch tube needs to be turned on based on the rotor position of the motor, so that the upper bridge arm switch tube of the second inverter bridge arm can be controlled to be in the on state subsequently.

[0181] Exemplarily, the controller may acquire space vector data, wherein the space vector data may include a plurality of space sectors, wherein each space sector corresponds to different switch state information.

[0182] For ease of understanding, the embodiment of the present application is introduced in the form of an accompanying drawing corresponding to the space vector data. Figure 5 is a schematic diagram of the space vector diagram provided in the embodiment of the present application. As shown in Figure 5, the space vector data in the embodiment of the present application may include multiple space sectors (for example, space sectors 1-space sectors 6 in Figure 5), wherein each space sector corresponds to different switch state information, for example, space sector 1 corresponds to switch state information U4 and switch state information U6, space sector 2 corresponds to switch state information U2 and switch state information U6, ..., space sector 6 corresponds to switch state information U4 and switch state information U5. It should be understood that the data from left to right in the different switch state information respectively represent the on-off state of the upper bridge arm switch tube connected to the corresponding phase stator winding, wherein "0" represents the off state and "1" represents the on state.

[0183] Furthermore, the controller may determine a first spatial sector in which the rotor of the motor is located, and a second spatial sector that is symmetrical to the first spatial sector.

[0184] In the embodiment of the present application, the controller can obtain the rotor position of the motor and thereby determine, based on the rotor position, the first spatial sector in the spatial vector data corresponding to the rotor and a second spatial sector symmetrical to the first spatial sector. For example, assuming that the first spatial sector in which the motor rotor is located is spatial sector 1, the second spatial sector symmetrical to the first spatial sector is spatial sector 4.

[0185] Furthermore, the controller may determine the second inverter bridge arm according to switch state information corresponding to the first spatial sector and the second spatial sector.

[0186] In an embodiment of the present application, the controller can select any switch state information from the switch state information corresponding to the first spatial sector and the second spatial sector, and determine the second inverter bridge arm based on the data in the selected switch state information, so that the angle between the magnetic field generated by the stator magnetic field and the magnetic field of the rotor during inductive excitation is smaller, thereby making the torque fluctuation generated at the beginning of heating smaller.

[0187] For example, assuming that the first spatial sector in which the rotor of the motor is located is spatial sector 1, the controller selects switch status information U4 (100) from the switch status information U4 and U6 corresponding to spatial sector 1, and the switch status information U1 and U3 corresponding to spatial sector 4. The controller can then determine the inverter bridge arm BA1 connected to the A-phase stator winding among the three inverter bridge arms as the second inverter bridge arm based on the data in the switch status information U4 (100).

[0188] It can be seen that in the embodiment of the present application, by determining the second inverter bridge arm of the upper bridge arm switch tube that needs to be turned on among the three inverter bridge arms in the appropriate switching circuit according to the rotor position of the motor, so that the angle between the magnetic field generated by the stator magnetic field and the magnetic field of the rotor during inductive excitation is smaller, thereby making the torque fluctuation generated at the beginning of heating smaller.

[0189] Figure 6 is a schematic diagram of the current flow when the motor provided by an embodiment of the present application is in the stator winding energy storage stage. As shown in Figure 6, assuming that the second inverter bridge arm is the inverter bridge arm BA1 connected to the A-phase stator winding among the three inverter bridge arms, and the first inverter bridge arm includes the inverter bridge arm BA2 connected to the B-phase stator winding and the inverter bridge arm BA3 connected to the C-phase stator winding, then when the motor is in the stator winding energy storage stage, the upper bridge arm switch tube V1 of the inverter bridge arm BA1 is in the on state, and the lower bridge arm switch tube V5 of the inverter bridge arm BA2 connected to the B-phase stator winding and the lower bridge arm switch tube V6 of the inverter bridge arm BA3 connected to the C-phase stator winding are both in the on state, forming a discharge path for the battery to serve as the motor, so that the current at both ends of the battery is from the positive pole of the battery → switch tube V1 → A-phase stator winding → B-phase stator winding and C-phase stator winding → switch tube V5 and switch tube V6 → negative pole of the battery.

[0190] 2) When the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the off state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state to disconnect the battery from the discharge path of the motor, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged.

[0191] FIG7 is a schematic diagram of the current flow direction of the motor provided by the embodiment of the present application when it is in the stator winding freewheeling stage. As shown in FIG7 , assuming that the second inverter bridge arm is the inverter bridge arm BA1 connected to the A-phase stator winding among the three inverter bridge arms, and the first inverter bridge arm includes the inverter bridge arm BA2 connected to the B-phase stator winding and the inverter bridge arm BA3 connected to the C-phase stator winding, then when the motor is in the stator winding freewheeling stage, the upper bridge arm switch tube V1 of the inverter bridge arm BA1 connected to the A-phase stator winding is switched to the disconnected state (disconnecting the battery as the discharge path of the motor). ), and the lower arm switch tube V5 of the inverter bridge arm BA2 connected to the B-phase stator winding and the lower arm switch tube V6 of the inverter bridge arm BA3 connected to the C-phase stator winding continue to be in the on state, and internal freewheeling is performed by utilizing the body diode D4 of the lower arm switch tube of the inverter bridge arm BA1 connected to the A-phase stator winding, wherein the stator winding current direction of the motor can be: B-phase stator winding and C-phase stator winding → switch tube V5 and switch tube V6 → body diode D4 → A-phase stator winding → B-phase stator winding and C-phase stator winding.

[0192] 3) When the motor is in the stator winding discharge phase, the lower-arm switch in the first inverter bridge arm of the switching circuit is switched to the off state, forming a charging path for the motor to the battery, facilitating the motor to discharge the battery and transfer the stored electrical energy to the battery. The motor's stator winding is in an energy-discharging state (i.e., the energy stored in the motor's stator winding is released to the battery), causing the current in each phase of the motor's stator winding to be in the stator winding discharge phase, where the current gradually decreases. The first inverter bridge arm is the bridge arm in which the lower-arm switch in the switching circuit is in the on state when the motor is in the stator winding energy storage phase.

[0193] Figure 8 is a schematic diagram of the current flow when the motor provided by an embodiment of the present application is in the stator winding discharge stage. As shown in Figure 8, assuming that the second inverter bridge arm is the inverter bridge arm BA1 connected to the A-phase stator winding among the three inverter bridge arms, and the first inverter bridge arm includes the inverter bridge arm BA2 connected to the B-phase stator winding and the inverter bridge arm BA3 connected to the C-phase stator winding, then when the motor is in the stator winding discharge stage, the lower bridge arm switch tube V5 of the inverter bridge arm BA2 connected to the B-phase stator winding and the lower bridge arm switch tube V6 of the inverter bridge arm BA3 connected to the C-phase stator winding are switched to the disconnected state, forming a charging path for the motor to the battery, so that the energy stored in the stator winding of the motor is released to the battery, wherein the current at both ends of the battery is from the negative pole of the battery → body diode D4 → A-phase stator winding → B-phase stator winding and C-phase stator winding → body diode D2 and body diode D3 → positive pole of the battery.

[0194] 4) During the stator winding current gap phase, the lower-arm switching transistor in the first inverter bridge arm remains off, forming an energy oscillation path between the capacitor C in the heating circuit and the battery. Because the energy stored in the motor's stator winding has been fully released, the current in each stator winding phase is in the zero-current stator winding current gap phase. During this phase, the capacitor in the heating circuit oscillates with the battery, improving energy utilization during the battery heating process.

[0195] In an embodiment of the present application, when the motor is in different stages, the on-off states of each switching tube in the three inverter bridge arms in the switching circuit are different, so that the current direction of each phase stator winding remains unchanged during the battery heating process of the motor, so as to increase the stator winding current harmonics of the motor and disperse the vibration noise energy of the battery heating process of the motor, thereby improving the vibration noise problem during the battery heating process of the motor.

[0196] In some embodiments, FIG9 is a flow chart of a battery heating method provided in other embodiments of the present application. Based on the above embodiments, the present embodiment of the present application introduces and illustrates a possible implementation method of "controlling the on / off state of the switch tube in the switch circuit in response to the heating enable signal" in step S202 when the motor includes a three-phase stator winding (excluding a neutral line). As shown in FIG9, the method of the embodiment of the present application may include:

[0197] Step S901, control the upper bridge arm switch tube of the second inverter bridge arm in the switch circuit to be in the on state, and the lower bridge arm switch tube in the first inverter bridge arm other than the second inverter bridge arm in the switch circuit to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0198] In this step, the controller can control the upper arm switch tube of the second inverter bridge arm among the three inverter bridge arms in the switching circuit to be in the on state, and the lower arm switch tube of the first inverter bridge arm other than the second inverter bridge arm among the three inverter bridge arms to be in the on state, forming a discharge path for the battery to serve the motor (for example, as shown in Figure 6, the positive pole of the battery → switch tube V1 → A-phase stator winding → B-phase stator winding and C-phase stator winding → switch tube V5 and switch tube V6 → negative pole of the battery), so that the battery discharges the motor, that is, the stator winding of the motor is in the excitation energy storage state (or it is called the motor is in the stator winding energy storage stage), so that the current of each phase stator winding of the motor is in the stator winding energy storage stage where the current gradually increases.

[0199] Step S902: When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the battery as the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0200] In this step, when the controller detects that the running state of the motor meets the preset freewheeling condition, it controls the upper bridge arm switch tube that is turned on in the second inverter bridge arm in the above step S901 to switch to the off state, so as to disconnect the battery as the discharge path of the motor, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged. For example, as shown in Figure 7, after disconnecting the battery as the discharge path of the motor, the direction of the stator winding current of the motor can be: B-phase stator winding and C-phase stator winding → switch tube V5 and switch tube V6 → body diode D4 → A-phase stator winding → B-phase stator winding and C-phase stator winding. It can be seen that the stator winding of the motor is in the internal freewheeling state (or it is called the motor is in the stator winding freewheeling stage).

[0201] For example, when the controller detects that the duration of the excitation energy storage state exceeds the preset energy storage time, or the current of the stator winding reaches the preset current, it can determine that the operating state of the motor meets the preset freewheeling condition; of course, the controller can also determine whether the operating state of the motor meets the preset freewheeling condition in other ways, which is not limited to this in the embodiments of the present application.

[0202] Step S903: When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge stage.

[0203] In this step, when the controller detects that the time of the freewheeling stage exceeds the preset freewheeling time, it can control the lower bridge arm switch tube that is turned on in the first inverter bridge arm in the above steps S901 and S902 to switch to the off state, forming a charging path for the motor to serve the battery (for example, the negative pole of the battery in Figure 8 → body diode D4 → A-phase stator winding → B-phase stator winding and C-phase stator winding → body diode D2 and body diode D3 → positive pole of the battery), so that the motor discharges the battery, that is, the stator winding of the motor is in an energy release and discharge state (that is, the energy stored in the stator winding of the motor is released to the battery), so that the current of each phase stator winding of the motor is in the stator winding discharge stage where the current gradually decreases.

[0204] Step S904: After detecting that the energy stored in the stator winding of the motor has been released, control the lower bridge arm switch tube in the first inverter bridge arm to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery in the heating circuit, so that the motor is in the stator winding current gap stage.

[0205] In this step, after detecting that the energy stored in the stator winding of the motor has been released, the controller controls the lower bridge arm switch tube in the first inverter bridge arm in the above step S903 to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the capacitor discharges the battery, that is, the motor is in the stator winding current gap stage, so that the current of each phase stator winding of the motor is in the stator winding current gap stage where the current is zero.

[0206] It should be understood that the above steps S901 to S904 may be steps that are cyclically repeated until the controller detects that the heating stop condition is met.

[0207] In an embodiment of the present application, by controlling the on / off states of the upper arm switch tube of the second inverter bridge arm and the lower arm switch tube of the first inverter bridge arm among the three inverter bridge arms in the switch circuit, the motor heats the battery while maintaining the current direction of each phase stator winding unchanged, so as to increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor heating the battery. In addition, the controller can also control the gap duration of the motor in the stator winding current gap state, thereby reducing the effective value of the stator winding current while maintaining the effective value of the battery current waveform unchanged, thereby further reducing the motor noise. Therefore, compared with traditional technologies, the embodiment of the present application can effectively improve the motor noise while ensuring that the original battery heating effect remains unchanged.

[0208] In some embodiments, the present application describes the case where the motor includes a three-phase stator winding and a neutral line. To facilitate understanding, the structure of the battery heating circuit is first described in the present application. Figure 10 is a schematic diagram of the structure of the battery heating circuit provided in other embodiments of the present application. As shown in Figure 10, the battery heating circuit of the present application embodiment may include: a heating circuit and a controller (not shown in Figure 10), wherein the heating circuit may include: a motor 103 and a switch circuit 102 connected to the motor 103 and the battery 101, respectively.

[0209] Exemplarily, the switching circuit 102 may include a neutral bridge arm BA4 disposed between the neutral line L of the motor 103 and the battery 101, three inverter bridge arms (e.g., BA1, BA2, and BA3 in FIG10 ) disposed between the three-phase stator windings of the motor 103 (e.g., A, B, and C in FIG10 ) and the battery 101, and a capacitor C connected in parallel with the three inverter bridge arms. The first end of each inverter bridge arm and the first end of the neutral bridge arm BA4 are connected to the positive electrode of the battery 101, the second end of each inverter bridge arm and the second end of the neutral bridge arm BA4 are connected to the negative electrode of the battery 101, the third ends of the three inverter bridge arms are respectively connected to the three-phase stator windings of the motor 103 in a one-to-one correspondence, and the third end of the neutral bridge arm BA4 is connected to the neutral line L of the motor. Among them, each inverter bridge arm can include: an upper bridge arm switch tube and a lower bridge arm switch tube, and the neutral bridge arm can include an upper bridge arm switch tube and a lower bridge arm switch tube. For example, the neutral bridge arm BA4 in Figure 10 can include an upper bridge arm switch tube V and a lower bridge arm switch tube V8.

[0210] It should be noted that any switching tube in the embodiments of the present application can be a switching tube including a body diode. For example, diode D7 in FIG10 is the body diode of switching tube V7, and diode D8 is the body diode of switching tube V8.

[0211] It should be understood that the control end (for example, the gate) of each switching tube in the embodiment of the present application is connected to the controller (not shown in Figure 10), so that the controller can send a control signal to the corresponding switching tube through the control end of any switching tube to control the on and off state of the corresponding switching tube.

[0212] In the following embodiments of the present application, the on-off states of the switching tubes in the three inverter bridge arms and the neutral bridge arm in the switching circuit when the motor is in different stages are introduced.

[0213] In one possible implementation, 1) when the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to serve the motor. 2) when the motor is in the stator winding freewheeling stage, the upper arm switch tube in each inverter bridge arm is switched to the off state to disconnect the discharge path for the battery to serve the motor, and the lower arm switch tube in the neutral bridge arm continues to be in the on state. 3) when the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm is switched to the off state, forming a charging path for the motor to serve the battery. 4) when the motor is in the stator winding current gap stage, the lower arm switch tube in the neutral bridge arm continues to be in the off state, forming an energy oscillation path between the capacitor and the battery.

[0214] Due to the particularity of the motor structure with a neutral line, the three-phase stator winding of the motor can be supplied with the same-phase current. In this implementation, when the motor is in the stator winding energy storage stage, the upper-arm switching tubes in each inverter bridge arm of the switching circuit are in the on state, and the lower-arm switching tubes in the neutral bridge arm are in the on state, forming a discharge path for the battery to the motor, so that the battery can discharge the motor and transfer the stored electrical energy to the motor. The stator winding of the motor is in an excitation energy storage state (i.e., the stator inductance of the motor is in an energy accumulation and increase state), thereby causing the current of each phase stator winding of the motor to be in the stator winding energy storage stage with gradually increasing current.

[0215] Figure 11 is a second schematic diagram of the current flow when the motor provided in an embodiment of the present application is in the stator winding energy storage stage. As shown in Figure 11, when the motor is in the stator winding energy storage stage, the upper bridge arm switch tube V1 of the inverter bridge arm BA1 connected to the A-phase stator winding, the upper bridge arm switch tube V2 of the inverter bridge arm BA2 connected to the B-phase stator winding, and the upper bridge arm switch tube V3 of the inverter bridge arm BA3 connected to the C-phase stator winding are in the on state, and the lower bridge arm switch tube V8 of the neutral bridge arm BA4 are all in the on state, forming a discharge path for the battery to serve as the motor, so that the current at both ends of the battery is from the positive pole of the battery → switch tube V1, switch tube V2 and switch tube V3 → A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → switch tube V8 → negative pole of the battery.

[0216] In this implementation, when the motor is in the stator winding freewheeling stage, the upper arm switch tube in each inverter bridge arm is switched to the off state to disconnect the battery as the discharge path for the motor, and the lower arm switch tube in the neutral bridge arm continues to be in the on state, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged.

[0217] FIG12 is a second schematic diagram of the current flow direction of the motor provided by the embodiment of the present application when it is in the stator winding freewheeling stage. As shown in FIG12, when the motor is in the stator winding freewheeling stage, the upper bridge arm switch tube V1 of the inverter bridge arm BA1 connected to the A-phase stator winding, the upper bridge arm switch tube V2 of the inverter bridge arm BA2 connected to the B-phase stator winding, and the upper bridge arm switch tube V3 of the inverter bridge arm BA3 connected to the C-phase stator winding are switched to the disconnected state, and the lower bridge arm switch tube V8 of the neutral bridge arm BA4 continues to be in the on state. By utilizing the A-phase stator winding connected to The body diode D4 of the lower bridge arm switch tube of the inverter bridge arm BA1, the body diode D5 of the lower bridge arm switch tube of the inverter bridge arm BA2 connected to the B-phase stator winding, and the body diode D6 of the lower bridge arm switch tube of the inverter bridge arm BA3 connected to the C-phase stator winding perform internal freewheeling, wherein the stator winding current direction of the motor can be: A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → switch tube V8 → body diode D4, body diode D5 and body diode D6 → A-phase stator winding, B-phase stator winding and C-phase stator winding.

[0218] In this implementation, when the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm is switched to the disconnected state, forming a charging path for the motor to serve as the battery, so that the motor can discharge the battery and transfer the electrical energy stored in the motor to the battery. The stator winding of the motor is in an energy release and discharge state (that is, the energy stored in the stator winding of the motor is released to the battery), so that the current of each phase stator winding of the motor is in the stator winding discharge stage where the current gradually decreases.

[0219] Figure 13 is a second schematic diagram of the current flow when the motor provided in an embodiment of the present application is in the stator winding discharge stage. As shown in Figure 13, when the motor is in the stator winding discharge stage, the lower bridge arm switch tube V8 in the neutral bridge arm BA4 is switched to the disconnected state, forming a charging path for the motor to the battery, so that the energy stored in the stator winding of the motor is released to the battery, wherein the current at both ends of the battery is from the negative pole of the battery → body diode D4, body diode D5 and body diode D6 → A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → body diode D7 → positive pole of the battery.

[0220] In this implementation, when the motor is in the stator winding current gap phase, the lower-arm switching transistor in the neutral bridge arm remains off, forming an energy oscillation path between the capacitor and the battery. Because the energy stored in the motor's stator winding has been fully released, the current in each phase of the stator winding is in the zero-current stator winding current gap phase. During this phase, the capacitor in the heating circuit oscillates with the battery, improving energy utilization during the battery heating process.

[0221] In another possible implementation, 1) when the motor is in the stator winding energy storage stage, the lower arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to serve the motor. 2) when the motor is in the stator winding freewheeling stage, the lower arm switch tube in each inverter bridge arm is switched to the off state to disconnect the discharge path for the battery to serve the motor, and the upper arm switch tube in the neutral bridge arm continues to be in the on state. 3) when the motor is in the stator winding discharge stage, the upper arm switch tube in the neutral bridge arm is switched to the off state to form a charging path for the motor to serve the battery. 4) when the motor is in the stator winding current gap stage, the upper arm switch tube in the neutral bridge arm continues to be in the off state, forming an energy oscillation path between the capacitor and the battery.

[0222] In this implementation, when the motor is in the stator winding energy storage stage, the lower arm switch tubes in each inverter bridge arm in the switching circuit are in the on state, and the upper arm switch tubes in the neutral bridge arm are in the on state, forming a discharge path for the battery to the motor, so that the battery discharges the motor to transfer the electrical energy stored in the battery to the motor, and the stator winding of the motor is in the excitation energy storage state (that is, the stator inductance of the motor is in an energy accumulation and rising state), so that the current of each phase stator winding of the motor is in the stator winding energy storage stage where the current gradually increases.

[0223] For example, referring to Figure 11, when the motor is in the stator winding energy storage stage, the lower bridge arm switch tube V4 of the inverter bridge arm BA1 connected to the A-phase stator winding, the lower bridge arm switch tube V5 of the inverter bridge arm BA2 connected to the B-phase stator winding and the lower bridge arm switch tube V6 of the inverter bridge arm BA3 connected to the C-phase stator winding are in the on state, and the upper bridge arm switch tube V7 of the neutral bridge arm BA4 are all in the on state, so that the current at both ends of the battery is from the positive pole of the battery → switch tube V7 → neutral line L → A-phase stator winding, B-phase stator winding and C-phase stator winding → switch tube V4, switch tube V5 and switch tube V6 → negative pole of the battery.

[0224] In this implementation, when the motor is in the stator winding freewheeling stage, the lower arm switch tube in each inverter bridge arm is switched to the disconnected state to disconnect the battery as the discharge path for the motor, and the upper arm switch tube in the neutral bridge arm continues to be in the on state, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged.

[0225] For example, referring to FIG12 , when the motor is in the stator winding freewheeling stage, the lower bridge arm switch tube V4 of the inverter bridge arm BA1 connected to the A-phase stator winding, the lower bridge arm switch tube V5 of the inverter bridge arm BA2 connected to the B-phase stator winding, and the lower bridge arm switch tube V6 of the inverter bridge arm BA3 connected to the C-phase stator winding are switched to the disconnected state, and the upper bridge arm switch tube V7 of the neutral bridge arm BA4 continues to be in the on state. By utilizing the inverter bridge arm BA1 connected to the A-phase stator winding, the stator winding of the motor is turned off. The body diode D1 of the upper arm switching tube, the body diode D2 of the upper arm switching tube of the inverter bridge arm BA2 connected to the B-phase stator winding, and the body diode D3 of the above-mentioned bridge arm switching tube of the inverter bridge arm BA3 connected to the C-phase stator winding perform internal freewheeling, wherein the stator winding current direction of the motor can be: switching tube V7 → neutral line L → A-phase stator winding, B-phase stator winding and C-phase stator winding → body diode D1, body diode D2 and body diode D3 → switching tube V7.

[0226] In this implementation, when the motor is in the stator winding discharge stage, the upper arm switch tube in the neutral bridge arm is switched to the disconnected state, forming a charging path for the motor to serve as the battery, so that the motor can discharge the battery and transfer the electrical energy stored in the motor to the battery. The stator winding of the motor is in an energy release and discharge state (that is, the energy stored in the stator winding of the motor is released to the battery), so that the current of each phase stator winding of the motor is in the stator winding discharge stage where the current gradually decreases.

[0227] For example, referring to Figure 13, when the motor is in the stator winding discharge stage, the upper arm switch tube V7 in the neutral bridge arm BA4 is switched to the disconnected state, forming a charging path for the motor to the battery, so that the energy stored in the stator winding of the motor is released to the battery, wherein the current at both ends of the battery is from the negative pole of the battery → body diode D8 → neutral line L → A-phase stator winding, B-phase stator winding and C-phase stator winding → body diode D1, body diode D2 and body diode D3 → positive pole of the battery.

[0228] In this implementation, when the motor is in the stator winding current gap phase, the upper-arm switching transistor in the neutral bridge arm remains off, forming an energy oscillation path between the capacitor and the battery. Because the energy stored in the motor's stator winding has been fully released, the current in each phase of the stator winding is in the zero-current stator winding current gap phase. During this phase, the capacitor in the heating circuit oscillates with the battery, improving energy utilization during the battery heating process.

[0229] In an embodiment of the present application, when the motor is in different stages, the on-off states of each switching tube in the three inverter bridge arms and the neutral bridge arm are different, so that the current direction of each phase stator winding remains unchanged during the battery heating process of the motor, so as to increase the stator winding current harmonics of the motor and disperse the vibration noise energy of the battery heating process of the motor, thereby improving the vibration noise problem during the battery heating process of the motor.

[0230] In some embodiments, FIG14 is a flow chart of a battery heating method provided in other embodiments of the present application. Based on the above embodiments, the present embodiment introduces another possible implementation of "controlling the on / off state of the switch in the switch circuit in response to the heating enable signal" in step S202 when the motor includes a three-phase stator winding and a neutral line. As shown in FIG14 , the method of the embodiment of the present application may include:

[0231] Step S1401: Control the upper arm switch tubes in each inverter bridge arm to be in the on state, and the lower arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to the motor, so that the motor is in the stator winding energy storage stage.

[0232] In this step, the controller can control the upper arm switch tubes in each inverter bridge arm to be in the on state, and the lower arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to serve the motor (for example, as shown in Figure 11, the positive pole of the battery → switch tube V1, switch tube V2 and switch tube V3 → A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → switch tube V8 → negative pole of the battery), so that the battery can discharge the motor, that is, the stator winding of the motor is in the excitation energy storage state (or it is called the motor is in the stator winding energy storage stage), so that the current of each phase stator winding of the motor is in the stator winding energy storage stage where the current gradually increases.

[0233] Step S1402: When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0234] In this step, when the controller detects that the running state of the motor meets the preset freewheeling condition, it can control the upper bridge arm switch tube in each inverter bridge arm to switch to the disconnected state to disconnect the battery as the discharge path of the motor, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged. For example, as shown in Figure 12, after disconnecting the battery as the discharge path of the motor, the stator winding current direction of the motor can be: A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → switch tube V8 → body diode D4, body diode D5 and body diode D6 → A-phase stator winding, B-phase stator winding and C-phase stator winding. It can be seen that the stator winding of the motor is in the internal freewheeling state (or it is called the motor is in the stator winding freewheeling stage).

[0235] Step S1403: When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge phase.

[0236] In this step, when the controller detects that the time of the freewheeling stage exceeds the preset freewheeling time, it can control the lower bridge arm switch tube in the neutral bridge arm to switch to the disconnected state, forming a charging path for the motor to serve as the battery (for example, the negative pole of the battery in Figure 13 → body diode D4, body diode D5 and body diode D6 → A-phase stator winding, B-phase stator winding and C-phase stator winding → neutral line L → body diode D7 → positive pole of the battery), so that the motor discharges the battery, that is, the stator winding of the motor is in an energy release and discharge state (that is, the energy stored in the stator winding of the motor is released to the battery), so that the current of each phase stator winding of the motor is in the stator winding discharge stage where the current gradually decreases.

[0237] Step S1404: After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch tube in the neutral bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

[0238] In this step, after detecting that the energy stored in the stator winding of the motor has been released, the controller can control the lower bridge arm switch tube in the neutral bridge arm to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the capacitor discharges the battery, that is, the motor is in the stator winding current gap stage, so that the current of each phase stator winding of the motor is in the stator winding current gap stage where the current is zero.

[0239] It should be understood that the above steps S1401 to S1403 may be steps that are cyclically repeated until the controller detects that the heating stop condition is met.

[0240] In an embodiment of the present application, by controlling the on / off states of the upper arm switch tubes of each inverter bridge arm and the lower arm switch tubes in the neutral bridge arm in the switching circuit, the motor heats the battery while maintaining the current direction of each phase stator winding unchanged, so as to increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor heating the battery. In addition, the controller can also control the gap duration of the motor in the stator winding current gap state, thereby reducing the effective value of the stator winding current while maintaining the effective value of the battery current waveform unchanged, thereby further reducing the motor noise. Therefore, compared with traditional technologies, the embodiment of the present application can effectively improve the motor noise while ensuring that the original battery heating effect remains unchanged.

[0241] In some embodiments, FIG15 is a flow chart of a battery heating method provided in other embodiments of the present application. Based on the above embodiments, the present embodiment introduces another possible implementation of "controlling the on / off state of the switch in the switch circuit in response to the heating enable signal" in step S202 when the motor includes a three-phase stator winding and a neutral line. As shown in FIG15 , the method of the embodiment of the present application may include:

[0242] Step S1501: Control the lower bridge arm switch tubes in each inverter bridge arm to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to the motor, so that the motor is in the stator winding energy storage stage.

[0243] In this step, the controller can control the lower arm switch tubes in each inverter bridge arm to be in the on state, and the upper arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to serve the motor (for example, refer to the positive pole of the battery in Figure 11 → switch tube V7 → neutral line L → A-phase stator winding, B-phase stator winding and C-phase stator winding → switch tube V4, switch tube V5 and switch tube V6 → negative pole of the battery), so that the battery can discharge the motor, that is, the stator winding of the motor is in the excitation energy storage state (or it is called the motor is in the stator winding energy storage stage), so that the current of each phase stator winding of the motor is in the stator winding energy storage stage where the current gradually increases.

[0244] Step S1502: When it is detected that the running state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0245] In this step, when the controller detects that the operating state of the motor meets the preset freewheeling condition, it can control the lower bridge arm switch tube in each inverter bridge arm to switch to the disconnected state to disconnect the battery as the discharge path for the motor, so that the stator winding of the motor is in the internal freewheeling state (that is, there is no energy interaction between the battery and the stator inductance of the motor), so that the current of each phase stator winding of the motor is in the stator winding freewheeling stage where the current remains unchanged. For example, referring to Figure 12, after disconnecting the battery as the discharge path for the motor, the direction of the stator winding current of the motor can be: switch tube V7 → neutral line L → A phase stator winding, B phase stator winding and C phase stator winding → body diode D1, body diode D2 and body diode D3 → switch tube V7. It can be seen that the stator winding of the motor is in the internal freewheeling state (or it is called the motor is in the stator winding freewheeling stage).

[0246] Step S1503: When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge phase.

[0247] In this step, when the controller detects that the time of the freewheeling stage exceeds the preset freewheeling time, it can control the upper bridge arm switch tube in the neutral bridge arm to switch to the disconnected state, forming a charging path for the motor to serve as the battery (for example, refer to the negative pole of the battery in Figure 13 → body diode D8 → neutral line L → A-phase stator winding, B-phase stator winding and C-phase stator winding → body diode D1, body diode D2 and body diode D3 → positive pole of the battery), so that the motor can discharge the battery, that is, the stator winding of the motor is in an energy release and discharge state (that is, the energy stored in the stator winding of the motor is released to the battery), so that the current of each phase stator winding of the motor is in the stator winding discharge stage where the current gradually decreases.

[0248] Step S1504: After detecting that the energy stored in the stator winding of the motor has been released, the upper bridge arm switch in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

[0249] In this step, after detecting that the energy stored in the stator winding of the motor has been released, the controller can control the upper bridge arm switch tube in the neutral bridge arm to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the capacitor discharges the battery, that is, the motor is in the stator winding current gap stage, so that the current of each phase stator winding of the motor is in the stator winding current gap stage where the current is zero.

[0250] It should be understood that the above steps S1501 to S1503 may be steps that are cyclically repeated until the controller detects that the heating stop condition is met.

[0251] In an embodiment of the present application, by controlling the on / off states of the lower arm switch tubes of each inverter bridge arm and the upper arm switch tubes in the neutral bridge arm in the switching circuit, the motor heats the battery while maintaining the current direction of each phase stator winding unchanged, so as to increase the stator winding current harmonics of the motor, thereby dispersing the vibration noise energy of the motor heating the battery. In addition, the controller can also control the gap duration of the motor in the stator winding current gap state, thereby reducing the effective value of the stator winding current while maintaining the effective value of the battery current waveform unchanged, thereby further reducing the motor noise. Therefore, compared with traditional technologies, the embodiment of the present application can effectively improve the motor noise while ensuring that the original battery heating effect remains unchanged.

[0252] It should be understood that, although the various steps in the flowcharts involved in the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the above embodiments may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0253] In some embodiments, based on the same inventive concept, an embodiment of the present application further provides a battery heating circuit. FIG16 is a schematic structural diagram of a battery heating circuit provided in other embodiments of the present application. As shown in FIG16 , based on the above embodiments, the battery heating circuit of an embodiment of the present application may include: a heating circuit HC and a controller 104, wherein the heating circuit HC may include a motor 103 and a switching circuit 102 respectively connected to the motor 103 and the battery 101.

[0254] Among them, the controller 104 is used to control the on-off state of the switching tube in the switching circuit in response to the heating enable signal after obtaining the heating enable signal, so as to heat the battery while keeping the current direction of each phase stator winding of the motor unchanged, wherein the heating enable signal is used to instruct the motor to heat the battery based on the heating circuit.

[0255] In some embodiments, the current of each phase stator winding changes periodically, and the current cycle of each phase stator winding includes: a stator winding energy storage stage where the current gradually increases, a stator winding freewheeling stage where the current remains unchanged, a stator winding discharge stage where the current gradually decreases, and a stator winding current gap stage where the current is zero.

[0256] In some embodiments, the battery is charged by a capacitor in the heating circuit during a stator winding current gap phase where the current is zero, wherein the capacitor is connected in series across the battery.

[0257] In some embodiments, the current of each phase stator winding is a half-wave current.

[0258] In some embodiments, the switching circuit 102 includes three inverter bridge arms disposed between the three-phase stator winding of the motor and the battery, and capacitors connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm is connected to the positive electrode of the battery, the second end of each inverter bridge arm is connected to the negative electrode of the battery, and the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor; each inverter bridge arm includes: an upper bridge arm switch tube and a lower bridge arm switch tube;

[0259] When the motor is in the stator winding discharge stage, the lower bridge arm switch tube in the first inverter bridge arm in the switching circuit is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electric energy stored in the motor to the battery; wherein, the first inverter bridge arm is the bridge arm in which the lower bridge arm switch tube in the switching circuit is in the on state when the motor is in the stator winding energy storage stage.

[0260] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

[0261] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state to disconnect the battery from the discharge path of the motor.

[0262] In some embodiments, when the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the first inverter bridge arm continues to be in an off state, forming an energy oscillation path between the capacitor in the heating circuit and the battery.

[0263] In some embodiments, the controller 104 is specifically configured to:

[0264] The upper bridge arm switch tube of the second inverter bridge arm in the control switching circuit is in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm other than the second inverter bridge arm in the switching circuit are in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0265] In some embodiments, when it is detected that the operating state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0266] In some embodiments, when it is detected that the time of the freewheeling phase exceeds the preset freewheeling time, the lower bridge arm switch tube in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to serve as the battery, so that the motor is in the stator winding discharge phase to heat the battery.

[0267] In some embodiments, after detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch tube in the first inverter bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery in the heating circuit, so that the motor is in the stator winding current gap stage.

[0268] In some embodiments, the controller 104 is further configured to:

[0269] The second inverter bridge arm is determined according to the rotor position of the motor.

[0270] In some embodiments, the controller 104 is specifically configured to:

[0271] Acquiring space vector data, where the switch state space vector data includes a plurality of space sectors, wherein each space sector corresponds to different switch state information;

[0272] Determine a first spatial sector in which a rotor of the motor is located, and a second spatial sector symmetrical to the first spatial sector;

[0273] The second inverter bridge arm is determined according to the switch state information corresponding to the first spatial sector and the second spatial sector.

[0274] In some embodiments, the switching circuit 102 includes: a neutral bridge arm disposed between the neutral line of the motor and the battery, three inverter bridge arms disposed between the three-phase stator winding of the motor and the battery, and a capacitor connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm and the first end of the neutral bridge arm are connected to the positive electrode of the battery, the second end of each inverter bridge arm and the second end of the neutral bridge arm are connected to the negative electrode of the battery, the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor, and the third end of the neutral bridge arm is connected to the neutral line of the motor; each inverter bridge arm includes: an upper bridge arm switching tube and a lower bridge arm switching tube, and the neutral bridge arm includes an upper bridge arm switching tube and a lower bridge arm switching tube;

[0275] When the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm in the switching circuit is switched to the off state; or, the upper arm switch tube in the neutral bridge arm is switched to the off state, forming a charging path for the motor to transfer the electrical energy stored in the motor to the battery.

[0276] In some embodiments, when the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state; or, the lower arm switch tube in each inverter bridge arm is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

[0277] In some embodiments, when the motor is in the stator winding freewheeling stage, the upper arm switch tube in each inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the neutral bridge arm continues to be in the on state; or, the lower arm switch tube in each inverter bridge arm is switched to the disconnected state, and the upper arm switch tube in the neutral bridge arm continues to be in the on state, so as to disconnect the battery from the discharge path of the motor.

[0278] In some embodiments, when the motor is in the stator winding current gap stage, the lower arm switch tube in the neutral bridge arm continues to be in the disconnected state; or, the upper arm switch tube in the neutral bridge arm continues to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery.

[0279] In some embodiments, the controller 104 is specifically configured to:

[0280] Control the upper bridge arm switch tubes in each inverter bridge arm to be in the on state, and the lower bridge arm switch tubes in the neutral bridge arm to be in the on state, forming a discharge path for the battery to the motor, so that the motor is in the stator winding energy storage stage; or

[0281] The lower bridge arm switch tubes in each inverter bridge arm are controlled to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm are controlled to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

[0282] In some embodiments, the controller 104 is specifically configured to:

[0283] When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage; or

[0284] When it is detected that the operating state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the battery from the discharge path of the motor, so that the motor is in the stator winding freewheeling stage.

[0285] In some embodiments, the controller 104 is specifically configured to:

[0286] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to the battery, so that the motor is in the stator winding discharge phase; or

[0287] When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

[0288] In some embodiments, the controller 104 is specifically configured to:

[0289] After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage; or

[0290] After detecting that the energy stored in the stator winding of the motor has been released, the upper arm switch tube in the neutral bridge arm is controlled to remain in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

[0291] In some embodiments, the switch tube in the switch circuit 102 includes an insulated gate bipolar transistor (IGBT) or a silicon carbide transistor.

[0292] In some embodiments, the controller 104 is specifically configured to:

[0293] When it is detected that the battery heating condition is met and the motor is in a non-operating state, a heating enable signal is generated; or,

[0294] Receive a heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

[0295] In some embodiments, the controller 104 is further configured to:

[0296] When the battery temperature is detected to be abnormal or the battery temperature reaches a preset temperature, the switch tube in the switch circuit is controlled to be in an off state; or,

[0297] When a battery temperature abnormality signal or a heating stop enable signal is received from the vehicle controller, the switch tube in the control switch circuit is in the disconnected state.

[0298] The battery heating circuit provided in the embodiment of the present application can be used in the technical solution in the above-mentioned battery heating method embodiment of the present application. Its implementation principle and technical effects are similar and will not be repeated here.

[0299] In some embodiments, an electrical device is also provided, including the battery heating circuit provided in the above embodiments of the present application. The implementation principle and technical effects thereof are similar and will not be described in detail here.

[0300] For example, the electrical equipment involved in the embodiments of the present application may be, but is not limited to, battery vehicles, electric vehicles, etc.

[0301] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. For purposes of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The processors involved in the various embodiments provided herein may be general-purpose processors, central processing units (CPUs), graphics processors (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like, without limitation thereto.

[0302] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery heating method, the method comprising: Obtaining a heating enable signal, wherein the heating enable signal is used to instruct the motor to heat the battery based on a heating circuit, the heating circuit including the motor and a switching circuit respectively connected to the motor and the battery; In response to the heating enable signal, the on / off state of the switch tube in the switching circuit is controlled so that the battery is heated while the current direction of each phase stator winding of the motor remains unchanged.

2. The method according to claim 1, wherein The current of the stator winding of each phase changes periodically, and the current cycle of the stator winding of each phase includes: a stator winding energy storage stage in which the current gradually increases, a stator winding freewheeling stage in which the current remains unchanged, a stator winding discharge stage in which the current gradually decreases, and a stator winding current gap stage in which the current is zero.

3. The method according to claim 2, wherein: During the stator winding current gap phase where the current is zero, the battery is charged by the capacitor in the heating circuit, wherein the capacitor is connected in series across the battery.

4. The method according to any one of claims 1 to 3, wherein The current of the stator winding of each phase is a half-wave current.

5. The method according to any one of claims 1 to 4, wherein When the motor is in the stator winding discharge stage, the lower bridge arm switch tube in the first inverter bridge arm in the switching circuit is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electric energy stored in the motor to the battery; wherein, the first inverter bridge arm is the bridge arm in which the lower bridge arm switch tube in the switching circuit is in the on state when the motor is in the stator winding energy storage stage.

6. The method according to claim 5, wherein: When the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tubes in the first inverter bridge arm except the second inverter bridge arm in the switching circuit are in the on state, forming a discharge path for the battery to transmit the electric energy stored in the battery to the motor.

7. The method according to claim 6, wherein: When the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state, so as to disconnect the discharge path of the battery for the motor.

8. The method according to any one of claims 5 to 7, wherein When the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the first inverter bridge arm continues to be in an off state, forming an energy oscillation path between the capacitor in the heating circuit and the battery.

9. The method according to claim 6, wherein: The step of controlling the on / off state of a switch tube in the switch circuit in response to the heating enable signal includes: The upper bridge arm switch tube of the second inverter bridge arm in the switching circuit is controlled to be in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm except the second inverter bridge arm in the switching circuit are controlled to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

10. The method according to claim 7, wherein: The step of controlling the on / off state of a switch tube in the switch circuit in response to the heating enable signal includes: When it is detected that the operating state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage.

11. The method according to claim 5, wherein: The step of controlling the on / off state of a switch tube in the switch circuit in response to the heating enable signal includes: When it is detected that the time of the freewheeling stage exceeds the preset freewheeling time, the lower bridge arm switch tube that is turned on in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

12. The method according to claim 8, wherein The step of controlling the on / off state of a switch tube in the switch circuit in response to the heating enable signal includes: After detecting that the energy stored in the stator winding of the motor has been released, the lower bridge arm switch tube in the first inverter bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor in the heating circuit and the battery, so that the motor is in the stator winding current gap stage.

13. The method according to claim 9, wherein: Before controlling the upper bridge arm switch tube of the second inverter bridge arm in the switching circuit to be in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm except the second inverter bridge arm in the switching circuit to be in the on state, the method further includes: The second inverter bridge arm is determined according to the rotor position of the motor.

14. The method according to claim 13, wherein: The determining the second inverter bridge arm according to the rotor position of the motor includes: Acquiring space vector data, wherein the switch state space vector data includes a plurality of space sectors, wherein each of the space sectors corresponds to different switch state information; determining a first spatial sector in which a rotor of the motor is located, and a second spatial sector symmetrical to the first spatial sector; The second inverter bridge arm is determined according to switch state information corresponding to the first spatial sector and the second spatial sector.

15. The method according to any one of claims 1 to 4, wherein: When the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm in the switching circuit is switched to the disconnected state; or, the upper arm switch tube in the neutral bridge arm is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electrical energy stored in the motor to the battery.

16. The method according to claim 15, wherein When the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state; or, the lower arm switch tube in each inverter bridge arm is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

17. The method according to claim 16, wherein When the motor is in the stator winding freewheeling stage, the upper bridge arm switch tubes in each inverter bridge arm are switched to the disconnected state, and the lower bridge arm switch tubes in the neutral bridge arm continue to be in the on state; or, the lower bridge arm switch tubes in each inverter bridge arm are switched to the disconnected state, and the upper bridge arm switch tubes in the neutral bridge arm continue to be in the on state, so as to disconnect the battery from serving as the discharge path for the motor.

18. The method according to any one of claims 15 to 17, wherein: When the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the neutral bridge arm continues to be in the disconnected state; or, the upper bridge arm switch tube in the neutral bridge arm continues to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery.

19. The method according to claim 16, wherein The step of controlling the on / off state of a switch tube in the switch tube circuit in response to the heating enable signal includes: Controlling the upper bridge arm switch tubes in each inverter bridge arm to be in an on state, and the lower bridge arm switch tubes in the neutral bridge arm to be in an on state, to form a discharge path for the battery to the motor, so that the motor is in a stator winding energy storage stage; or The lower bridge arm switch tubes in each inverter bridge arm are controlled to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm are controlled to be in the on state, so as to form a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

20. The method according to claim 17, wherein The step of controlling the on / off state of a switch tube in the switch tube circuit in response to the heating enable signal includes: When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery to the motor, so that the motor is in the stator winding freewheeling stage; or When it is detected that the operating state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage.

21. The method according to claim 15, wherein The step of controlling the on / off state of a switch tube in the switch tube circuit in response to the heating enable signal includes: When it is detected that the freewheeling phase time exceeds a preset freewheeling time length, controlling the lower bridge arm switch tube in the neutral bridge arm to switch to an off state, forming a charging path for the motor to charge the battery, so that the motor is in a stator winding discharge phase; or When it is detected that the time of the freewheeling stage exceeds the preset freewheeling time, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

22. The method according to claim 18, wherein The step of controlling the on / off state of a switch tube in the switch tube circuit in response to the heating enable signal includes: After detecting that the energy stored in the stator winding of the motor has been released, controlling the lower bridge arm switch tube in the neutral bridge arm to continue to be in an off state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in a stator winding current gap stage; or After detecting that the energy stored in the stator winding of the motor has been released, the upper bridge arm switch tube in the neutral bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

23. The method according to any one of claims 1 to 22, wherein The obtaining of the heating enable signal includes: When it is detected that the battery heating condition is met and the motor is in a non-operating state, generating the heating enable signal; or, Receive the heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

24. The method according to any one of claims 1 to 22, wherein The method further comprises: When the battery temperature is detected to be abnormal or the battery temperature reaches a preset temperature, the switch tube in the switch circuit is controlled to be in the disconnected state. state.

25. The method according to any one of claims 1 to 22, wherein The method further comprises: When a battery temperature abnormality signal or a heating stop enable signal sent by a vehicle controller is received, the switch tube in the switch circuit is controlled to be in an off state.

26. A battery heating circuit, comprising: A heating circuit and a controller, wherein the heating circuit includes a motor and a switching circuit connected to the motor and a battery respectively; The controller is used to control the on-off state of the switching tube in the switching circuit in response to the heating enable signal after obtaining the heating enable signal, so that the battery can be heated while the current direction of each phase stator winding of the motor remains unchanged, wherein the heating enable signal is used to instruct the motor to heat the battery based on the heating circuit.

27. The battery heating circuit according to claim 26, wherein: The current of the stator winding of each phase changes periodically, and the current cycle of the stator winding of each phase includes: a stator winding energy storage stage in which the current gradually increases, a stator winding freewheeling stage in which the current remains unchanged, a stator winding discharge stage in which the current gradually decreases, and a stator winding current gap stage in which the current is zero.

28. The battery heating circuit according to claim 27, wherein: During the stator winding current gap phase where the current is zero, the battery is charged by the capacitor in the heating circuit, wherein the capacitor is connected in series across the battery.

29. The method according to any one of claims 26 to 28, wherein The current of the stator winding of each phase is a half-wave current.

30. The battery heating circuit according to any one of claims 26 to 29, wherein: The switching circuit includes three inverter bridge arms arranged between the three-phase stator winding of the motor and the battery, and capacitors connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm is connected to the positive electrode of the battery, the second end of each inverter bridge arm is connected to the negative electrode of the battery, and the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor; each inverter bridge arm includes: an upper bridge arm switching tube and a lower bridge arm switching tube; When the motor is in the stator winding discharge stage, the lower bridge arm switch tube in the first inverter bridge arm in the switching circuit is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electric energy stored in the motor to the battery; wherein, the first inverter bridge arm is the bridge arm in which the lower bridge arm switch tube in the switching circuit is in the on state when the motor is in the stator winding energy storage stage.

31. The battery heating circuit according to claim 30, wherein: When the motor is in the stator winding energy storage stage, the upper arm switch tube of the second inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tubes in the first inverter bridge arm except the second inverter bridge arm in the switching circuit are in the on state, forming a discharge path for the battery to transmit the electric energy stored in the battery to the motor.

32. The battery heating circuit according to claim 31, wherein: When the motor is in the stator winding freewheeling stage, the upper arm switch tube of the second inverter bridge arm is switched to the disconnected state, and the lower arm switch tube in the first inverter bridge arm continues to be in the on state, so as to disconnect the discharge path of the battery for the motor.

33. The battery heating circuit according to any one of claims 30 to 32, wherein: When the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the first inverter bridge arm continues to be in an off state, forming an energy oscillation path between the capacitor in the heating circuit and the battery.

34. The battery heating circuit according to claim 31, wherein: The controller is specifically used for: The upper bridge arm switch tube of the second inverter bridge arm in the switching circuit is controlled to be in the on state, and the lower bridge arm switch tubes in the first inverter bridge arm except the second inverter bridge arm in the switching circuit are controlled to be in the on state, forming a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

35. The battery heating circuit according to claim 32, wherein: The controller is specifically used for: When it is detected that the operating state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in the second inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage.

36. The battery heating circuit according to claim 30, wherein: The controller is specifically used for: When it is detected that the time of the freewheeling stage exceeds the preset freewheeling time length, the lower bridge arm switch tube that is turned on in the first inverter bridge arm is controlled to switch to the off state, forming a charging path for the motor to serve as the battery, so that the motor is in the stator winding discharge stage to heat the battery.

37. The battery heating circuit according to claim 33, wherein: The controller is specifically used to: after detecting that the energy stored in the stator winding of the motor has been released, control the lower bridge arm switch tube in the first inverter bridge arm to continue to be in the disconnected state, forming an energy oscillation path between the capacitor in the heating circuit and the battery, so that the motor is in the stator winding current gap stage.

38. The battery heating circuit according to claim 34, wherein: The controller is also used to: The second inverter bridge arm is determined according to the rotor position of the motor.

39. The battery heating circuit according to claim 38, wherein: The controller is specifically used for: Acquiring space vector data, wherein the switch state space vector data includes a plurality of space sectors, wherein each of the space sectors corresponds to different switch state information; determining a first spatial sector in which a rotor of the motor is located, and a second spatial sector symmetrical to the first spatial sector; The second inverter bridge arm is determined according to switch state information corresponding to the first spatial sector and the second spatial sector.

40. The battery heating circuit according to any one of claims 26 to 29, wherein: The switching circuit includes: a neutral bridge arm arranged between the neutral line of the motor and the battery, three inverter bridge arms arranged between the three-phase stator winding of the motor and the battery, and a capacitor connected in parallel with the three inverter bridge arms; wherein the first end of each inverter bridge arm and the first end of the neutral bridge arm are connected to the positive electrode of the battery, the second end of each inverter bridge arm and the second end of the neutral bridge arm are connected to the negative electrode of the battery, the third ends of the three inverter bridge arms are respectively connected to the three-phase stator winding of the motor, and the third end of the neutral bridge arm is connected to the neutral line of the motor; each inverter bridge arm includes: an upper bridge arm switching tube and a lower bridge arm switching tube, and the neutral bridge arm includes an upper bridge arm switching tube and a lower bridge arm switching tube; When the motor is in the stator winding discharge stage, the lower arm switch tube in the neutral bridge arm in the switching circuit is switched to the disconnected state; or, the upper arm switch tube in the neutral bridge arm is switched to the disconnected state, forming a charging path for the motor to the battery, so as to transfer the electrical energy stored in the motor to the battery.

41. The battery heating circuit according to claim 40, wherein: When the motor is in the stator winding energy storage stage, the upper arm switch tube in each inverter bridge arm in the switching circuit is in the on state, and the lower arm switch tube in the neutral bridge arm is in the on state; or, the lower arm switch tube in each inverter bridge arm is in the on state, and the upper arm switch tube in the neutral bridge arm is in the on state, forming a discharge path for the battery to transfer the electrical energy stored in the battery to the motor.

42. The battery heating circuit according to claim 41, wherein: When the motor is in the stator winding freewheeling stage, the upper bridge arm switch tubes in each inverter bridge arm are switched to the disconnected state, and the lower bridge arm switch tubes in the neutral bridge arm continue to be in the on state; or, the lower bridge arm switch tubes in each inverter bridge arm are switched to the disconnected state, and the upper bridge arm switch tubes in the neutral bridge arm continue to be in the on state, so as to disconnect the battery from serving as the discharge path for the motor.

43. The battery heating circuit according to any one of claims 40 to 42, wherein: When the motor is in the stator winding current gap stage, the lower bridge arm switch tube in the neutral bridge arm continues to be in the disconnected state; Alternatively, the upper bridge arm switch tube in the neutral bridge arm continues to be in an off state, forming an energy oscillation path between the capacitor and the battery.

44. The battery heating circuit according to claim 41, wherein: The controller is specifically used for: Controlling the upper bridge arm switch tubes in each inverter bridge arm to be in an on state, and the lower bridge arm switch tubes in the neutral bridge arm to be in an on state, to form a discharge path for the battery to the motor, so that the motor is in a stator winding energy storage stage; or The lower bridge arm switch tubes in each inverter bridge arm are controlled to be in the on state, and the upper bridge arm switch tubes in the neutral bridge arm are controlled to be in the on state, so as to form a discharge path for the battery to serve as the motor, so that the motor is in the stator winding energy storage stage.

45. The battery heating circuit according to claim 42, wherein: The controller is specifically used for: When it is detected that the running state of the motor meets the preset freewheeling condition, the upper bridge arm switch tube in each inverter bridge arm is controlled to switch to the off state to disconnect the discharge path of the battery to the motor, so that the motor is in the stator winding freewheeling stage; or When it is detected that the operating state of the motor meets the preset freewheeling condition, the lower bridge arm switch tube in each inverter bridge arm is controlled to switch to the disconnected state to disconnect the discharge path of the battery for the motor, so that the motor is in the stator winding freewheeling stage.

46. ​​The battery heating circuit of claim 40, wherein: The controller is specifically used for: When it is detected that the freewheeling phase time exceeds the preset freewheeling time length, the lower bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, thereby forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge phase; or When it is detected that the time of the freewheeling stage exceeds the preset freewheeling time, the upper bridge arm switch tube in the neutral bridge arm is controlled to switch to the disconnected state, forming a charging path for the motor to charge the battery, so that the motor is in the stator winding discharge stage.

47. The battery heating circuit of claim 43, wherein: The controller is specifically used for: After detecting that the energy stored in the stator winding of the motor has been released, controlling the lower bridge arm switch tube in the neutral bridge arm to continue to be in an off state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in a stator winding current gap stage; or After detecting that the energy stored in the stator winding of the motor has been released, the upper bridge arm switch tube in the neutral bridge arm is controlled to continue to be in the disconnected state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current gap stage.

48. The battery heating circuit according to any one of claims 26-47, wherein: The switch tube in the switch circuit includes an insulated gate bipolar transistor (IGBT) or a silicon carbide transistor.

49. The battery heating circuit according to any one of claims 26 to 47, wherein: The controller is specifically used for: When it is detected that the battery heating condition is met and the motor is in a non-operating state, generating the heating enable signal; or, Receive the heating enable signal sent by the vehicle controller, wherein the heating enable signal is sent by the vehicle controller when it receives a heating request sent by the battery management system BMS and detects that the motor is in a non-working state.

50. The battery heating circuit according to any one of claims 26-47, wherein: The controller is also used to: When it is detected that the battery temperature is abnormal or the battery temperature reaches a preset temperature, the switch tube in the switch circuit is controlled to be in an off state; or, When a battery temperature abnormality signal or a heating stop enable signal sent by a vehicle controller is received, the switch tube in the switch circuit is controlled to be in an off state.

51. An electrical device comprising the battery heating circuit according to any one of claims 26 to 50.

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