Battery heating method, battery heating circuit, and electric device

A battery heating circuit, wherein

• the battery heating circuit comprises a heating circuit and a controller, wherein the heating circuit comprises a motor, a battery, and a switch circuit respectively connected to the motor and the battery;
• the controller is configured to, upon acquiring a heating enable signal, control switching states of switching transistors in the switch circuit in response to the heating enable signal, so as to generate a half-wave current in the motor to heat the battery, wherein the heating enable signal is configured to indicate that the motor is to heat the battery based on the heating circuit, wherein a cycle of the half-wave current comprises:
• a stator winding energy storage stage in which the current gradually increases, a stator winding freewheeling stage in which the current remains constant, a stator winding discharge stage in which the current gradually decreases, and a stator winding current dead-time stage in which the current is zero, wherein during the stator winding current dead-time stage in which the current is zero, a capacitor in the heating circuit charges the battery, wherein the capacitor is connected in series across the terminals of the battery;
• and
• the switch circuit comprises three inverter bridge arms disposed between the motor and the battery and respectively connected to the three-phase stator winding of the motor and a capacitor connected in parallel with the three inverter bridge arms, each inverter bridge arm comprising:
• an upper bridge arm switching transistor and a lower bridge arm switching transistor;
• and, wherein
• when the motor is in a stator winding energy storage stage, an upper bridge arm switching transistor in a target inverter bridge arm among the three inverter bridge arms is in the on state, and lower bridge arm switching transistors in other inverter bridge arms are in the on state;
• when the motor is in a stator winding freewheeling stage, the upper bridge arm switching transistor in the target inverter bridge arm switches to the off state, and the lower bridge arm switching transistors in the other inverter bridge arms remain in the on state;
• when the motor is in a stator winding discharge stage, the lower bridge arm switching transistors in the other inverter bridge arms switch to the off state;
• and
• when the motor is in a stator winding current dead-time stage, the lower bridge arm switching transistors in the other inverter bridge arms remain in the off state.

The battery heating circuit according to 16, wherein the switch circuit comprises:

• a neutral bridge arm disposed between a neutral line of the motor and the battery, three inverter bridge arms disposed between the motor and the battery and respectively connected to the three-phase stator winding of the motor, and a capacitor connected in parallel with the three inverter bridge arms, each inverter bridge arm comprising:
• an upper bridge arm switching transistor and a lower bridge arm switching transistor, the neutral bridge arm comprising an upper bridge arm switching transistor and a lower bridge arm switching transistor;
• wherein
• when the motor is in a stator winding energy storage stage, the upper bridge arm switching transistor in each of the inverter bridge arms is in the on state, and the lower bridge arm switching transistor in the neutral bridge arm is in the on state;
• or the lower bridge arm switching transistor in each of the inverter bridge arms is in the on state, and the upper bridge arm switching transistor in the neutral bridge arm is in the on state;
• when the motor is in a stator winding freewheeling stage, the upper bridge arm switching transistor in each of the inverter bridge arms switches to the off state, and the lower bridge arm switching transistor in the neutral bridge arm remains in the on state;
• or the lower bridge arm switching transistor in each of the inverter bridge arms switches to the off state, and the upper bridge arm switching transistor in the neutral bridge arm remains in the on state;
• when the motor is in a stator winding discharge stage, the lower bridge arm switching transistor in the neutral bridge arm is in the off state, or the upper bridge arm switching transistor in the neutral bridge arm is in the off state;
• and
• when the motor is in a stator winding current dead-time stage, the lower bridge arm switching transistor in the neutral bridge arm remains in the off state, or the upper bridge arm switching transistor in the neutral bridge arm remains in the off state;
• and, wherein the controller is configured to:
• control the upper bridge arm switching transistor in each of the inverter bridge arms to be in the on state and the lower bridge arm switching transistor in the neutral bridge arm to be in the on state, forming a discharge path from the battery to the motor, so that the motor is in the stator winding energy storage stage;
• control the lower bridge arm switching transistor in each of the inverter bridge arms to be in the on state and the upper bridge arm switching transistor in the neutral bridge arm to be in the on state, forming a discharge path from the battery to the motor, so that the motor is in the stator winding energy storage stage;
• upon detecting that an operating state of the motor satisfies a preset freewheeling condition, control the upper bridge arm switching transistor in each of the inverter bridge arms to switch to the off state to disconnect the discharge path from the battery to the motor, so that the motor is in the stator winding freewheeling stage;
• upon detecting that the operating state of the motor satisfies the preset freewheeling condition, control the lower bridge arm switching transistor in each of the inverter bridge arms to switch to the off state to disconnect the discharge path from the battery to the motor, so that the motor is in the stator winding freewheeling stage;
• upon detecting that a duration of the freewheeling stage exceeds a preset freewheeling duration, control the lower bridge arm switching transistor in the neutral bridge arm to switch to the off state, forming a charging path from the motor to the battery, so that the motor is in the stator winding discharge stage;
• upon detecting that the duration of the freewheeling stage exceeds the preset freewheeling duration, control the upper bridge arm switching transistor in the neutral bridge arm to switch to the off state, forming a charging path from the motor to the battery, so that the motor is in the stator winding discharge stage;
• upon detecting that energy stored in the stator windings of the motor is fully released, control the lower bridge arm switching transistor in the neutral bridge arm to remain in the off state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current dead-time stage;
• or
• upon detecting that the energy stored in the stator windings of the motor is fully released, control the upper bridge arm switching transistor in the neutral bridge arm to remain in the off state, forming an energy oscillation path between the capacitor and the battery, so that the motor is in the stator winding current dead-time stage.