Motor controller heating system and control method thereof, vehicle

Abstract

The application provides a motor controller heating system and a control method thereof and a vehicle, relates to the technical field of vehicle control, and the method comprises the following steps: controlling the conduction states of a first switching module, a second switching module, a third switching module and an inverter, so that an energy storage element, the inverter, two-phase windings in a three-phase motor and a power battery are sequentially connected to form a charging and discharging circuit of the power battery; obtaining a target current, a target voltage of the power battery, a phase current of a first-phase winding in the three-phase motor and a current voltage of the power battery; obtaining the duty cycle of a control pulse of a first-phase bridge arm in the inverter connected with the first-phase winding according to the target current, the target voltage, the current voltage and the phase current, and controlling the first-phase bridge arm according to the duty cycle, so as to adjust the current of the charging and discharging circuit, the mutual charging and discharging between the power battery and the energy storage element can be realized, the heating capacity of the power battery is improved, the capacity loss is reduced, and the current can be accurately controlled.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a motor controller heating system and its control method, and a vehicle. Background Technology

[0002] In low-temperature conditions, new energy vehicles face challenges such as charging difficulties, low discharge efficiency, and reduced cycle life of their power batteries. Typically, the batteries need to be heated before operation. Current technology requires connecting the battery to the neutral point of the motor to achieve this heating. Summary of the Invention

[0003] In view of this, this application provides a motor controller heating system and its control method, as well as a vehicle. By setting a second switch module and a third switch module, it is possible to realize mutual charging and discharging between the power battery and the energy storage element, improve the heating capacity of the power battery, reduce energy loss, and accurately control the current.

[0004] To achieve the above objectives, this application provides the following technical solution: a control method for a motor controller heating system, the motor controller heating system comprising: an inverter, a first switch module, a second switch module, a third switch module, a three-phase motor, and an energy storage element; the energy storage element, the third switch module, the inverter, the first switch module, the three-phase motor, the second switch module, and a power battery are sequentially connected; the control method comprises: controlling the conduction state of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, and the three-phase motor... The two-phase winding and the power battery are sequentially connected to form the charging and discharging circuit of the power battery; the target current and target voltage of the power battery, the phase current of the first phase winding in the three-phase motor and the current voltage of the power battery are obtained, wherein the first phase winding is the winding in the three-phase motor connected to the inverter in the charging and discharging circuit; the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained according to the target current, the target voltage, the current voltage and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charging and discharging circuit.

[0005] In one embodiment of this application, obtaining the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding based on the target current, the target voltage, the current voltage, and the phase current includes: obtaining a current compensation term based on the target voltage and the current voltage; calculating the difference between the target current and the phase current, and then adding it to the current compensation term to obtain the current to be adjusted; and performing proportional-integral adjustment based on the current to be adjusted to obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding.

[0006] In one embodiment of this application, obtaining a compensation value based on the target voltage and the current voltage includes: calculating the difference between the target voltage and the current voltage; and performing proportional-integral adjustment on the difference to obtain a current compensation term.

[0007] In one embodiment of this application, before the control of the first switch module and the second switch module is turned on, the following steps are included: controlling the vehicle to be in neutral and controlling the three-phase motor to rotate to a preset angle position; controlling the inverter to operate in pulse heating mode.

[0008] In one embodiment of this application, controlling the three-phase motor to rotate to a preset angle position includes: if the energy storage element, the inverter, the first phase winding, the second phase winding of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the three-phase motor is controlled to rotate to a third angle position corresponding to the three-phase motor; if the energy storage element, the inverter, the first phase winding, the third phase winding of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the three-phase motor is controlled to rotate to a second angle position corresponding to the three-phase motor; if the energy storage element, the inverter, the second phase winding, the third phase winding of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the three-phase motor is controlled to rotate to a first angle position corresponding to the three-phase motor.

[0009] In one embodiment of this application, controlling the conduction states of the first switch module, the second switch module, the third switch module, and the inverter to sequentially connect the energy storage element, the inverter, two-phase windings of the three-phase motor, and the power battery to form a charging and discharging circuit for the power battery includes: controlling the first switch module and the third switch module to turn off and the second switch module to turn on; controlling the first phase bridge arm in the inverter to form a Boost circuit with the two-phase windings of the three-phase motor to discharge the power battery; and controlling the first phase bridge arm in the inverter to form a Buck circuit with the two-phase windings of the three-phase motor to charge the power battery.

[0010] In one embodiment of this application, controlling the first phase bridge arm in the inverter to form a Boost circuit with the first phase bridge arm and two phase windings in the three-phase motor includes: controlling the upper bridge arm of the first phase bridge arm in the inverter to turn off, so that the diode connected in parallel with the upper bridge arm of the first phase bridge arm, the first phase winding connected with the first phase bridge arm, and the second phase winding of the three-phase motor form a Boost circuit.

[0011] In one embodiment of this application, controlling the first phase bridge arm in the inverter to form a Buck step-down circuit with the first phase bridge arm and two phase windings in the three-phase motor includes: controlling the upper bridge arm of the first phase bridge arm in the inverter to conduct, so that the upper bridge arm of the first phase bridge arm, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor form a Buck step-down circuit.

[0012] As a second aspect of this application, this application also provides a motor controller heating system, including: an inverter, a first switch module, a second switch module, a third switch module, a three-phase motor, and an energy storage element; the energy storage element, the third switch module, the inverter, the first switch module, the motor windings, the second switch module, and the power battery are connected in sequence; the motor controller heating system further includes a controller, the controller being used to: control the conduction state of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, and the three-phase motor... Two-phase windings and the power battery are sequentially connected to form a charging and discharging circuit for the power battery; the target current and target voltage of the power battery, the phase current of the first phase winding in the three-phase motor, and the current voltage of the power battery are obtained, wherein the first phase winding is the winding in the three-phase motor connected to the inverter in the charging and discharging circuit; the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained according to the target current, the target voltage, the current voltage, and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charging and discharging circuit.

[0013] As a third aspect of this application, this application also provides a vehicle, including: the aforementioned motor controller heating system.

[0014] This application provides a control method for a motor controller heating system. The motor controller heating system includes: an inverter, a first switch module, a second switch module, a third switch module, a three-phase motor, and an energy storage element; the energy storage element, the third switch module, the inverter, the first switch module, the three-phase motor, the second switch module, and a power battery are connected sequentially; a charging and discharging circuit for the power battery is formed by controlling the second switch module and the third switch module; the control method includes: controlling the conduction state of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, two phase windings of the three-phase motor, and the power battery are connected sequentially to form a charging and discharging circuit for the power battery; obtaining the power battery's... The system uses the target current, target voltage, phase current of the first phase winding in the three-phase motor, and current voltage of the power battery. The first phase winding is the winding in the three-phase motor connected to the inverter in the charging and discharging circuit. Based on the target current, target voltage, current voltage, and phase current, the duty cycle of the control pulse for the first phase bridge arm in the inverter connected to the first phase winding is obtained. The first phase bridge arm is controlled according to the duty cycle to adjust the current in the charging and discharging circuit. The conduction state of each switch in the first phase bridge arm can be controlled according to the duty cycle, thereby adjusting the operating time of the charging and discharging circuits. This enables mutual charging and discharging between the power battery and energy storage components, improves the heating capacity of the power battery, reduces energy loss, and allows for precise current control. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a motor controller heating system provided in an embodiment of this application.

[0017] Figure 2 This is a flowchart illustrating the control method of the motor controller heating system provided in an embodiment of this application.

[0018] Figure 3 This is a circuit diagram of a motor controller heating system provided in an embodiment of this application.

[0019] Figure 4 A schematic diagram of the equivalent motor drive circuit of the motor controller heating system provided in the embodiments of this application.

[0020] Figure 5 A schematic diagram of the charging and discharging circuit of the motor controller heating system provided in the embodiments of this application.

[0021] Figure 6 A schematic diagram of the power battery discharge of the motor controller heating device provided in the embodiments of this application.

[0022] Figure 7 A schematic diagram of the power battery charging of the motor controller heating device provided in the embodiments of this application.

[0023] Figure 8 An example diagram of the control method for the motor controller heating system provided in the embodiments of this application.

[0024] Figure 9 This is a schematic diagram of the charging and discharging current adjustment of the motor controller heating system provided in an embodiment of this application. Detailed Implementation

[0025] This application provides a motor controller heating device, a powertrain, and a vehicle. By setting a second switch module and a third switch module to form a charging and discharging circuit for the power battery, and adjusting the duty cycle of the control pulse according to the target current, phase current, target voltage, and current voltage to adjust the current of the charging and discharging circuit, it is possible to achieve mutual charging and discharging between the power battery and the energy storage element, improve the heating capacity of the power battery, reduce energy loss, and accurately control the current.

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In low-temperature conditions, new energy vehicles face challenges such as charging difficulties, low discharge efficiency, and reduced cycle life of their power batteries. Typically, the batteries need to be heated before operation. Current technology requires connecting the battery to the neutral point of the motor to heat it, which necessitates significant modifications to the motor and results in high costs.

[0028] The technical solution of this application embodiment is applicable to the application scenario of heating and discharging the power battery in new energy vehicles. This application embodiment provides a motor controller heating system, including: an inverter, a first switch module, a second switch module, a third switch module, a three-phase motor, and an energy storage element; the energy storage element, the third switch module, the inverter, the first switch module, the three-phase motor, the second switch module, and the power battery are connected sequentially.

[0029] When the first and third switch modules are off and the second switch module is closed, the power battery, the energy storage element, the first phase bridge arm of the inverter, and the two-phase windings of the three-phase motor form a charging and discharging circuit for the power battery. By adjusting the duty cycle of the first phase bridge arm of the inverter, the charging and discharging circuit can be adjusted, enabling mutual charging and discharging between the power battery and the energy storage element.

[0030] When the first and third switch modules are closed and the second switch module is closed, the power battery, the energy storage element, the inverter, and the three-phase motor form a motor drive circuit. By adjusting the duty cycle of each phase arm of the inverter, the control signal controlling the motor rotation can be adjusted, thereby realizing the adjustment of the motor's driving force.

[0031] Figure 1 The diagram shown is a structural schematic of a motor controller heating system provided in an embodiment of this application. Figure 1 As shown, the motor controller heating system includes: an inverter 10, an energy storage element C1, a three-phase motor 11, a first switch module 12, a second switch module 13, and a third switch module 14. The first terminal of the inverter 10 is connected to the first terminal of the power battery C via the third switch module 14, and the second terminal of the inverter 10 is connected to the second terminal of the power battery C. The first terminal of the first phase winding L1 of the three-phase motor 11 is connected to the midpoint of the first phase bridge arm in the inverter 10. The first terminal of the second phase winding L3 of the three-phase motor 11 is connected to the midpoint of the second phase bridge arm in the inverter 10 via the first switch module 12, and the first terminal of the third phase winding L2 of the three-phase motor 11 is connected to the midpoint of the third phase bridge arm in the inverter 10 via the first switch module 12. The first terminal of the second phase winding L3 of the three-phase motor 11 is also connected to the first terminal of the power battery C via the second switch module 13. In the three-phase motor 11, the second ends of the first phase winding L1, the second phase winding L3, and the second end of the second phase winding L3 are connected to form the neutral point of the three-phase motor. One end of the energy storage element C1 is connected to the first end of the inverter 10, and the other end of the energy storage element C1 is connected to the second end of the inverter 10.

[0032] It should be noted that the first phase winding can be any phase winding in a three-phase motor, the second phase winding is one of the other two phase windings different from the first phase winding, and the third phase winding is the other phase winding among the other two phase windings. This embodiment uses the first phase winding as the U-phase winding, the second phase winding as the W-phase winding, and the third phase winding as the V-phase winding as an example for illustration. The first, second, and third phase windings in the three-phase motor are respectively connected to the midpoints of the first, second, and third phase bridge arms in the inverter.

[0033] In inverter 10, the first, second, and third phase bridge arms each include an upper bridge arm and a lower bridge arm. The upper bridge arm of the first phase bridge arm includes a first switch Q1 and a diode connected in parallel with the first switch Q1. The upper bridge arm of the second phase bridge arm includes a second switch Q3 and a diode connected in parallel with the second switch Q3. The upper bridge arm of the third phase bridge arm includes a third switch Q2 and a diode connected in parallel with the third switch Q2. The lower bridge arm of the first phase bridge arm includes a fourth switch Q4 and a diode connected in parallel with the fourth switch Q4. The lower bridge arm of the second phase bridge arm includes a fifth switch Q6 and a diode connected in parallel with the fifth switch Q6. The lower bridge arm of the third phase bridge arm includes a sixth switch Q5 and a diode connected in parallel with the sixth switch Q5. The midpoint of the first phase bridge arm is the intermediate connection point connecting the first switch Q1 and the fourth switch Q4. The midpoint of the second phase bridge arm is the intermediate connection point connecting the second switch Q3 and the fifth switch Q6. The midpoint of the third phase bridge arm is the intermediate connection point connecting the third switch Q2 and the sixth switch Q5.

[0034] The motor controller heating system provided in this application embodiment further includes a controller, which is used for:

[0035] Controlling the conduction states of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, two-phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery;

[0036] The target current and target voltage of the power battery, the phase current of the first phase winding of the three-phase motor, and the current voltage of the power battery are obtained. The first phase winding is the winding of the three-phase motor connected to the inverter in the charging and discharging circuit.

[0037] The duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained based on the target current, the target voltage, the current voltage, and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charging and discharging circuit.

[0038] Further, the target current and target voltage of the power battery, the phase current of the first phase winding in the three-phase motor, and the current voltage of the power battery are obtained. The target current and target voltage of the power battery represent the maximum charge / discharge current and maximum charge / discharge voltage that the power battery can withstand, respectively. The specific values ​​of the target current and target voltage can be determined based on the actual temperature rise effect. A current sensor can be installed on the connection line between the first phase winding of the three-phase motor and the first phase bridge arm of the inverter to detect the phase current of the first phase winding in the three-phase motor. The current voltage of the power battery can be acquired by a voltage acquisition circuit.

[0039] Because the first switching module is disconnected, the connection between the second and third phase bridge arms of the inverter and the three-phase motor is broken. Only the first phase bridge arm of the inverter is connected to the charging and discharging circuit. Thus, the duty cycle of the control pulse of the first phase bridge arm of the inverter connected to the first phase winding is obtained according to the target current, the target voltage, the current voltage, and the phase current. Then, the conduction and turn-off times of the first switch Q1 and the fourth switch Q4 in the upper and lower bridge arms of the first phase bridge arm are controlled according to the duty cycle, thereby enabling precise control of the current in the charging and discharging circuit and reducing power loss.

[0040] For more specific control methods of the motor controller heating system, please refer to the control method examples below.

[0041] Based on the above-described motor controller heating system, this application provides a control method for the motor controller heating system, such as... Figure 2 As shown, the control method of the motor controller heating system includes:

[0042] Step S11: Control the conduction state of the first switch module, the second switch module, the third switch module and the inverter, so that the energy storage element, the inverter, the two-phase windings of the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery.

[0043] The first control module is disconnected, breaking the connection between the second phase bridge arm of the inverter and the second phase winding of the three-phase motor, as well as the connection between the third phase bridge arm of the inverter and the third phase winding of the three-phase motor. The second control module is disconnected, breaking the direct connection between the first terminal of the inverter and the first terminal of the power battery. The third control module is turned on, allowing the second phase winding of the three-phase motor to be directly connected to the first terminal of the power battery. In this way, the energy storage element, the inverter, two phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery. Subsequent control of this charging and discharging circuit allows for mutual charging and discharging between the power battery and the energy storage element.

[0044] Step S12: Obtain the target current and target voltage of the power battery, the phase current of the first phase winding of the three-phase motor, and the current voltage of the power battery. The first phase winding is the winding of the three-phase motor connected to the inverter in the charging and discharging circuit.

[0045] The three-phase motor includes the phase current of the first phase winding and the current voltage of the power battery. The target current and target voltage of the power battery represent the maximum charge / discharge current and voltage it can withstand, respectively, and their specific values ​​can be determined based on the actual temperature rise. A current sensor can be installed on the connection line between the first phase winding of the three-phase motor and the first phase bridge arm of the inverter to detect the phase current of the first phase winding. The current voltage of the power battery can be acquired by a voltage acquisition circuit. Subsequently, the actual current in the charge / discharge circuit can be adjusted based on the target current, target voltage, current voltage, and phase current of the first phase winding of the three-phase motor, thereby enabling precise control of the power battery's charge / discharge current and ensuring its stability.

[0046] Step S13: Obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding according to the target current, the target voltage, the current voltage and the phase current, and control the first phase bridge arm according to the duty cycle to adjust the current of the charging and discharging circuit.

[0047] In this embodiment, the control pulse of the first phase bridge arm in the inverter can control the conduction state of the first switch of the upper bridge arm and the fourth switch of the lower bridge arm in the first phase bridge arm. This allows the circuit formed by the sequential connection of the energy storage element, the inverter, two phase windings of the three-phase motor, and the power battery to either form a Boost circuit for discharging the power battery or a Buck circuit for discharging the power battery. The duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained based on the target current, the target voltage, the current voltage, and the phase current. This duty cycle allows control of the on and off times of the first and fourth switches in the first phase bridge arm within one cycle, thereby regulating the current in the charging and discharging circuit.

[0048] The control method of the motor controller heating system in this application embodiment forms a charging and discharging circuit for the power battery by controlling the second switch module and the third switch module, and adjusts the duty cycle of the control pulse according to the target current, target voltage, current voltage and phase current to adjust the current of the charging and discharging circuit. This enables mutual charging and discharging between the power battery and the energy storage element, improves the heating capacity of the power battery, reduces energy loss, and enables precise current control.

[0049] The motor controller heating system of this embodiment can operate in motor drive mode or heating mode, i.e., heating and charging / discharging the power battery. Therefore, the operating requirements of the motor controller heating system need to be determined first. If heating and charging / discharging the power battery is required, the vehicle needs to be adjusted accordingly to facilitate the motor controller heating system entering the power battery heating and charging / discharging state. Based on this, before step S11, the vehicle is put into neutral, and the three-phase motor is rotated to a preset angle position; the inverter is controlled to operate in pulse heating mode. Putting the vehicle into neutral ensures that the three-phase motor can rotate. Then, the three-phase motor is pre-positioned, i.e., controlled to rotate to a preset angle position, ensuring zero torque output from all three motors. The motor controller has torque mode, speed mode, pulse heating mode, etc., and switches to pulse heating mode during pulse heating.

[0050] The preset angle is set as needed and is related to two windings of the three-phase motor connected in the charging and discharging circuit. Taking the first, second, and third phases of the three-phase motor as U-phase, W-phase, and V-phase respectively, if the energy storage element, the inverter, the first and second phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery, then the three-phase motor is controlled to rotate to the angle position corresponding to the third phase of the three-phase motor. That is, if the V-phase of the three-phase motor is disconnected, and the energy storage element, the inverter, the U and W phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery, then the preset angle is 120°.

[0051] If the energy storage element, the inverter, the first phase winding and the third phase winding of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the three-phase motor is controlled to rotate to a second angular position corresponding to the three-phase motor. That is, if the W phase of the three-phase motor is disconnected, and the energy storage element, the inverter, the UV phase windings of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the preset angle is 240°.

[0052] If the energy storage element, the inverter, the second-phase winding and the third-phase winding of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the three-phase motor is controlled to rotate to a first angular position corresponding to the three-phase motor. That is, if the U-phase of the three-phase motor is disconnected, and the energy storage element, the inverter, the VW-phase windings of the three-phase motor, and the power battery are sequentially connected to form a charging and discharging circuit for the power battery, then the preset angle is 0°.

[0053] For the specific circuit diagram of the motor controller heating system, please refer to [link / reference]. Figure 3The first switching module includes a first control switch K4. The first terminal of the first control switch K4 is connected to the midpoint of the second phase bridge arm in the inverter, and the second terminal of the first control switch K4 is connected to the second phase winding L3 of the three-phase motor. By setting the first control switch K4, the second phase bridge arm of the inverter can be disconnected from the second phase winding of the three-phase motor during pulse heating mode. The first switching module also includes a second control switch K5. The first terminal of the second control switch K5 is connected to the midpoint of the third phase bridge arm in the inverter, and the second terminal of the second control switch K5 is connected to the third phase winding L2 of the three-phase motor. By setting the second control switch K5, the third phase bridge arm of the inverter can be disconnected from the third phase winding of the three-phase motor during pulse heating mode.

[0054] The motor controller heating system further includes a first current sensor A1 and a second current sensor A2. The first current sensor A1 is connected between the midpoint of the first bridge arm of the inverter and the first phase winding L1 of the three-phase motor. The second current sensor A2 is connected between the first control switch and the second phase winding L3 of the three-phase motor. The first current sensor A1 is used to detect the phase current flowing through the first phase winding of the three-phase motor, which is the current of the charging and discharging circuit. If the second phase winding of the second current sensor A2, which is away from the three-phase motor, is connected to the second switch module, then when the motor controller heating system operates in pulse heating mode, the second current sensor A2 is used to detect the current of the charging and discharging circuit, and the detected current is consistent with that of the first current sensor A1. When the motor controller heating system operates in other modes, the second current sensor A2 is used to detect the current flowing through the second phase winding of the three-phase motor.

[0055] The second switch module includes a third control switch K3. The first terminal of the third control switch K3 is connected to the first terminal of the power battery C, and the second terminal of the third control switch K3 is connected to the second phase winding L3 of the three-phase motor. The third control switch K3 is turned on when the motor controller heating system is operating in pulse heating mode, connecting the second phase winding of the three-phase motor to the first terminal of the power battery to form a charging and discharging circuit for the power battery. When the motor controller heating system is operating in other modes, the second switch module is turned off, disconnecting the connection between the second phase winding of the three-phase motor and the first terminal of the power battery, allowing the motor controller heating system to form a motor drive circuit.

[0056] The third switch module includes a fourth control switch K1, a fifth control switch K2, and a first resistor R1. The first terminal of the fourth control switch K1 is connected to the first terminal of the power battery C, and the second terminal of the fourth control switch K1 is connected to the first terminal of the inverter. The first terminal of the fifth control switch K2 is connected to the first terminal of the power battery C, and the second terminal of the fifth control switch K2 is connected to the first terminal of the inverter through the first resistor R1. When the motor controller heating system operates in other modes, the fourth control switch K1 is closed, enabling the motor controller heating system to form a motor drive circuit to drive the motor normally. The fifth control switch K2 and the first resistor R1 form a pre-charging circuit, which pre-charges the energy storage element C1 when the motor controller heating system operates in other modes, preventing damage to the device caused by sudden current changes in the motor drive circuit.

[0057] See Figure 4 When the first switch module is closed and the second switch module is open, the power battery C, energy storage element C1, inverter, and three-phase motor form a motor drive circuit to drive the three-phase motor to work normally. First, the fifth control switch K2 is turned on to precharge the energy storage element C1. Then, the fourth control switch K1 is turned on, while the fifth control switch K2 is turned off, driving the three-phase motor to work normally through the motor drive circuit.

[0058] When the first and third switch modules are open, and the second switch module is closed, i.e., the first control switch K4, the second control switch K5, the fourth control switch K1, and the fifth control switch K2 are open, and the third control switch K3 is closed, the energy storage element C1, the inverter, the three-phase motor, and the power battery C form the charging and discharging circuit of the power battery. Specifically, as follows... Figure 5 As shown, the first terminal of the power battery C is connected to the midpoint of the first phase bridge arm in the inverter via the second phase winding L3 and the first phase winding L1 of the three-phase motor connected in series. The midpoint of the first phase bridge arm is the intermediate connection point between the upper and lower bridge arms of the first phase bridge arm. The midpoint of the first phase bridge arm is connected to one end of the energy storage element C1 via the first switch Q1, and the midpoint of the first phase bridge arm is connected to the other end of the energy storage element C1 and the second terminal of the power battery C via the fourth switch Q4. The first terminal of the power battery C is the positive terminal, and the second terminal is the negative terminal. The energy storage element is preferably a capacitor. At this time, all switches in the second and third phase bridge arms of the inverter are in the off state.

[0059] In this embodiment, one phase of the three-phase motor is connected to the power battery via a control switch, and another phase is connected to the switching transistor in the inverter via a control switch. This allows for AC heating of the power battery without any changes to the three-phase motor or the power battery. Furthermore, once the motor is pre-positioned, the three-phase motor can operate without rotation. The common practice in the market is to connect the battery to the motor's neutral point via a relay; this embodiment does not require modification to the motor.

[0060] In this embodiment, before controlling the inverter to operate in pulse heating mode, the first control switch K4, the second control switch K5, the third control switch K3, and the fourth control switch K1 can be opened, and the fifth control switch K2 can be closed to pre-charge the energy storage element C1, making the voltage at both ends of the power battery equal to that at both ends of the energy storage element. Then, the first and third switch modules are opened, and the second switch module is closed, forming a charging and discharging circuit for the power battery consisting of the energy storage element C1, the inverter, the three-phase motor, and the power battery C.

[0061] Furthermore, by controlling the first phase bridge arm in the inverter that is not connected to the first switching module, a Boost circuit is first formed to enable the power battery to charge the energy storage element, and then a Buck circuit is formed to enable the energy storage element to charge the battery. This cycle is repeated to achieve heating and discharging of the power battery C.

[0062] In this embodiment, the switching between the Boost and Buck circuits is achieved by cyclically controlling the on / off state of the first switch Q1 in the first phase bridge arm. When the first switch Q1 is on, it charges the motor windings, and the load is powered by the energy storage element C1. When the first switch Q1 is off, the diode connected in parallel with the first switch Q1 is on, and the phase current cannot change abruptly. Therefore, the inductor current supplies power to the load and capacitor through the diode. The load consists of the three-phase motor and the internal equivalent resistance of each component. In the Buck-Boost circuit, the charging and discharging process of the capacitor, which serves as the energy storage element C1, generates certain losses: the capacitor is not an ideal component and has an internal equivalent series resistance (ESR). When current flows through the capacitor, the ESR induces Joule heating, leading to energy loss. During the charging and discharging process of a capacitor, the injection and release of charge will cause energy loss (dielectric loss) due to dielectric polarization; leakage current, ripple, etc. will also cause energy loss, resulting in less capacitor discharge energy and slow current decay. The deviation between the actual value and the demand value is adjusted by PID control as compensation and added to the demand current so that the current can remain stable and no longer decay.

[0063] In this embodiment of the application, when discharging the power battery, optionally, the first phase bridge arm in the inverter can be controlled to form a Boost circuit with two phase windings in the three-phase motor to achieve the discharge of the power battery. See also Figure 6 The first switch Q1 in the upper arm of the first phase bridge arm of the inverter is turned off, causing the diode connected in parallel with the first switch, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor to form a Boost circuit. Current flows from the positive terminal of the power battery C, sequentially through the second phase winding of the three-phase motor, the first phase winding of the three-phase motor, the diode connected in parallel with the first switch in the inverter, and the energy storage element, returning to the negative terminal of the power battery C. The power battery C charges the energy storage element C1 through this Boost circuit.

[0064] When the energy storage element charges the power battery, optionally, the first phase bridge arm in the inverter can be controlled to form a Buck step-down circuit with two phase windings in the three-phase motor to achieve power battery charging. See also Figure 7 The first switch in the upper arm of the first phase bridge arm of the inverter is turned on, causing the first switch, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor to form a Buck step-down circuit. Current flows from the first terminal of the energy storage element, sequentially through the first switch in the inverter, the first phase winding of the three-phase motor, the second phase winding of the three-phase motor, the positive terminal of the power battery, and the negative terminal of the power battery, returning to the second terminal of the energy storage element. The energy storage element C1 charges the power battery C through this Buck step-down circuit.

[0065] By controlling the battery charging and discharging current to a sinusoidal current through voltage boosting and bucking, AC heating of the power battery is achieved. The charging and discharging current of the power battery can be adjusted by regulating the on and off times of each switch in the first phase arm of the inverter. Adjusting the on and off times of each switch in the first phase arm is equivalent to adjusting the duty cycle of the control pulse for the first phase arm.

[0066] To accurately obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter, in this embodiment, optionally, a current compensation term is obtained based on the target voltage and the current voltage; the difference between the target current and the phase current is calculated and added to the current compensation term to obtain the current to be adjusted; proportional-integral (PID) adjustment is performed based on the current to be adjusted to obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding. The current to be adjusted is the current portion that needs to be adjusted. The purpose of this embodiment is to make the current in the charging and discharging circuit consistent with the target current. The greater the difference between the target current and the phase current, the smaller the difference between the target voltage and the current voltage, and the larger the current to be adjusted. After obtaining the current to be adjusted, proportional-integral-differential (PID) adjustment is performed on the selected current, that is, the current to be adjusted is adjusted proportionally, integrally, and derivatively according to the proportional coefficient, integral coefficient, and derivative coefficient, respectively. This embodiment mainly performs proportional and integral adjustment. After PID adjustment of the current to be adjusted, the duty cycle of the control pulse of the first phase bridge arm can be obtained. Subsequently, the conduction state of each switch in the first phase bridge arm can be adjusted according to the obtained duty cycle, thereby realizing the regulation of the current in the charging and discharging circuit.

[0067] The power battery uses sinusoidal current for charging and discharging. The current waveform formula is I=Asin(2*π*f*t), where A is the current amplitude, which cannot exceed the maximum charging and discharging current that the power battery can withstand; f is the current frequency, which cannot exceed the frequency value that the three-phase motor can withstand. A larger current amplitude results in better heating of the power battery, and a higher current frequency allows for more frequent charging and discharging, leading to better charging and discharging performance. Adjustments can be made according to specific actual needs. A negative current I indicates capacitor discharge, charging the battery; a positive current I indicates power battery discharge, charging the capacitor.

[0068] To accurately control the current in the charging and discharging circuit, it is necessary to accurately obtain the current compensation term. Therefore, in this embodiment, optionally, the difference between the target voltage and the current voltage is calculated; the difference is then adjusted proportionally and integrally to obtain the current compensation term. The current compensation term is mainly the difference between the target voltage and the current voltage. By adding a current compensation term, the accuracy of current regulation can be improved.

[0069] In this embodiment of the application, during the battery heating process, the battery charges the capacitor through a boost circuit and the capacitor charges the battery through a buck circuit. During this process, capacitor loss will cause current attenuation and deteriorate the control effect. Therefore, a current compensation term is added to compensate for the negative impact of this attenuation.

[0070] Taking the U-phase winding of a three-phase motor connected to the midpoint of the first bridge arm of the inverter, the W-phase of the three-phase motor connected to the midpoint of the second bridge arm of the inverter via a first control switch and connected to the positive terminal of the power battery via a third control switch, and the V-phase of the three-phase motor connected to the midpoint of the third bridge arm of the inverter via a second control switch as an example, an example of the control method of the motor controller heating system in this application embodiment is provided below. Figure 8 ,include:

[0071] Step 100: Put the whole vehicle in neutral.

[0072] Putting the vehicle in neutral ensures that the three-phase motor can rotate, facilitating subsequent AC charging and discharging of the power battery.

[0073] Step 101: Motor pre-positioning.

[0074] Rotate the rotor of the three-phase motor to 120° to ensure zero torque output. Disconnect phase V and phase W, and connect phase W to the power battery. Control phases U and W to form a circuit. The three-phase motor will not rotate, so only the current of phase U needs to be controlled.

[0075] Step 102: Switch to pulse heating mode.

[0076] The inverter has torque mode, speed mode, and pulse heating mode. For pulse heating, the inverter is first switched to pulse heating mode. Specifically, the first control switch K4, the second control switch K5, the fourth control switch K1, and the fifth control switch K2 are opened, while the third control switch K3 is closed. This creates a charging and discharging circuit for the power battery, consisting of the energy storage element C1, the inverter, the U and W phase windings of the three-phase motor, and the power battery C.

[0077] Step 103: The Boost battery charges the capacitor.

[0078] The first switch in the upper arm of the first phase bridge arm of the control inverter is turned off, so that the diode connected in parallel with the first switch, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor form a Boost circuit. The power battery charges the energy storage element through this Boost circuit.

[0079] Step 104: The Buck capacitor charges the battery.

[0080] The first switch in the upper arm of the first phase bridge arm of the control inverter is turned on, so that the first switch, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor form a Buck step-down circuit. The energy storage element charges the power battery through this Boost step-up circuit.

[0081] In steps 103 and 104, the duty cycle of the control pulse in the first phase bridge arm of the inverter is adjusted, thereby regulating the charging and discharging current of the power battery. (See also...) Figure 9 The system acquires the target current, target voltage, current voltage of the power battery, and the U-phase current in the three-phase motor. It then applies PID2 regulation to the difference between the target voltage and the current voltage to obtain a current compensation term. The difference between the target current and the U-phase current is calculated and added to the current compensation term to obtain the current to be adjusted. Further, PID1 regulation is applied based on this current to obtain the U-phase duty cycle. This U-phase duty cycle is the control pulse duty cycle of the first phase bridge arm in the inverter connected to the U-phase winding. Both PID1 and PID2 are proportional-integral (PI) adjustments, differing only in their proportional and integral coefficients. Based on the U-phase duty cycle, the conduction states of the first and fourth switches in the first phase bridge arm of the inverter can be adjusted, thereby regulating the charging and discharging current of the power battery.

[0082] In this embodiment, when the second control switch K5 is open, only the U and W phases are used to form a circuit, ensuring that the U and W phase currents are equal and the V phase current is 0. This pre-positions the three-phase motor to 120°, so when the U phase current is controlled, the three-phase motor outputs zero torque and will not rotate. Without the second control switch K5, the third switch Q2 and the sixth switch Q5 are open, but due to the diode's effect, a V phase diode freewheeling current exists in the inverter circuit, causing the capacitor voltage to rise. Adding the second control switch K5 relay, which opens the second control switch K5, eliminates the V phase diode freewheeling current circuit, significantly reducing the capacitor voltage; thus, a small-capacity capacitor is sufficient.

[0083] The control method of the motor controller heating system in this application embodiment uses existing power batteries, three-phase motors, and inverters. Only the inverter needs to be modified to achieve AC heating of the power battery, resulting in minimal modifications. Since only one phase bridge arm of the inverter is connected to the charging and discharging circuit, the diode freewheeling current is reduced, which greatly reduces the selection of capacitor capacity. It can be ensured that the three-phase motor does not rotate after pre-positioning, thus possessing strong reliability. The three-phase motor and inverter are used to realize the buck-boost bidirectional step-up and step-down function. The power battery and capacitors act as energy storage devices, charging and discharging each other, improving heating capacity and reducing energy loss. Moreover, the current controllability is good and the control is precise.

[0084] This application also provides a vehicle, including: the above-described motor controller heating system.

[0085] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0086] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0087] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0088] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0089] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0090] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A control method for a motor controller heating system, characterized in that, The motor controller heating system includes: an inverter, a first switch module, a second switch module, a third switch module, a three-phase motor, and an energy storage element; the energy storage element, the third switch module, the inverter, the first switch module, the three-phase motor, the second switch module, and the power battery are connected in sequence; The control method includes: Controlling the conduction states of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, two-phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery; The target current and target voltage of the power battery, the phase current of the first phase winding of the three-phase motor, and the current voltage of the power battery are obtained. The first phase winding is the winding of the three-phase motor connected to the inverter in the charging and discharging circuit. The duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained based on the target current, the target voltage, the current voltage, and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charging and discharging circuit.

2. The control method according to claim 1, characterized in that, The step of obtaining the duty cycle of the control pulse for the first phase bridge arm in the inverter connected to the first phase winding based on the target current, the target voltage, the current voltage, and the phase current includes: The current compensation term is obtained based on the target voltage and the current voltage; Calculate the difference between the target current and the phase current, and then add it to the current compensation term to obtain the current to be adjusted; The duty cycle of the control pulse for the first phase bridge arm in the inverter connected to the first phase winding is obtained by performing proportional-integral regulation based on the current to be adjusted.

3. The control method according to claim 2, characterized in that, The step of obtaining the compensation value based on the target voltage and the current voltage includes: Calculate the difference between the target voltage and the current voltage; The difference is adjusted proportionally and integrally to obtain the current compensation term.

4. The control method according to claim 1, characterized in that, Before the control of the first switch module and the second switch module to be turned on includes: Control the vehicle to shift into neutral and control the three-phase motor to rotate to a preset angle position; The inverter is controlled to operate in pulse heating mode.

5. The control method according to claim 1, characterized in that, The control of the three-phase motor to rotate to a preset angle position includes: If the energy storage element, the inverter, the first phase winding, the second phase winding of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery, then the three-phase motor is controlled to rotate to the third angular position corresponding to the three-phase motor. If the energy storage element, the inverter, the first phase winding and the third phase winding of the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, then the three-phase motor is controlled to rotate to the second angular position corresponding to the three-phase motor. If the energy storage element, the inverter, the second phase winding and the third phase winding of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery, then the three-phase motor is controlled to rotate to the first angular position corresponding to the three-phase motor.

6. The control method according to claim 1, characterized in that, The control of the conduction states of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, two-phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery, includes: The control module turns off the first switch module and the third switch module, and turns on the second switch module; The first phase bridge arm in the inverter is controlled to form a Boost circuit with two phase windings in the three-phase motor, so as to realize the discharge of the power battery. The first phase bridge arm in the inverter is controlled to form a Buck step-down circuit with two phase windings in the three-phase motor, so as to charge the power battery.

7. The control method according to claim 6, characterized in that, The step of controlling the first phase bridge arm in the inverter to form a Boost circuit with the first phase bridge arm and two phase windings in the three-phase motor includes: The upper arm of the first phase bridge arm in the inverter is turned off, so that the diode connected in parallel with the upper arm of the first phase bridge arm, the first phase winding connected with the first phase bridge arm, and the second phase winding of the three-phase motor form a Boost circuit.

8. The control method according to claim 6, characterized in that, The step of controlling the first phase bridge arm in the inverter to form a Buck step-down circuit with the two phase windings in the three-phase motor includes: The upper arm of the first phase bridge arm in the inverter is turned on, so that the upper arm of the first phase bridge arm, the first phase winding connected to the first phase bridge arm, and the second phase winding of the three-phase motor form a Buck step-down circuit.

9. A motor controller heating system, characterized in that, The motor controller heating system includes: The system comprises an inverter, a first switching module, a second switching module, a third switching module, a three-phase motor, and an energy storage element; the energy storage element, the third switching module, the inverter, the first switching module, the motor windings, the second switching module, and the power battery are connected in sequence. The motor controller heating system further includes a controller, which is used for: Controlling the conduction states of the first switch module, the second switch module, the third switch module, and the inverter, so that the energy storage element, the inverter, two-phase windings of the three-phase motor, and the power battery are sequentially connected to form the charging and discharging circuit of the power battery; The target current and target voltage of the power battery, the phase current of the first phase winding of the three-phase motor, and the current voltage of the power battery are obtained. The first phase winding is the winding of the three-phase motor connected to the inverter in the charging and discharging circuit. The duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding is obtained based on the target current, the target voltage, the current voltage, and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charging and discharging circuit.

10. A vehicle, characterized in that, The vehicle includes: the motor controller heating system as described in claim 9.

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