Motor controller heating system, control method thereof and vehicle

Abstract

The invention provides a motor controller heating system, a control method thereof and a vehicle, and relates to the technical field of vehicle control, and the method comprises the steps: controlling the conduction states of a first switch module, a second switch module, a third switch module and an inverter, the energy storage element, the inverter, the two-phase winding in the three-phase motor and the power battery are connected in sequence to form a charging and discharging loop of the power battery; obtaining a target current of the power battery and a phase current of a first phase winding in the three-phase motor; the duty ratio of a control pulse of a first phase bridge arm in an inverter connected with the first phase winding is obtained according to the target current and the phase current, the first phase bridge arm is controlled according to the duty ratio so as to adjust the current of the charging and discharging loop, and the duty ratio of the control pulse is adjusted according to the target current and the phase current so as to adjust the current of the charging and discharging loop. 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] The present application relates to the field of vehicle control technology, and in particular to a motor controller heating system and a control method thereof, and a vehicle. Background Art

[0002] New energy vehicles face challenges with charging difficulties, low discharge efficiency, and reduced cycle life in low-temperature conditions. This often requires heating the battery before it can be used. Existing technology requires connecting the battery to the neutral point of the motor to achieve heating. Summary of the Invention

[0003] In view of this, the present application provides a motor controller heating system, a control method thereof, and a vehicle, which forms a charge and discharge circuit of 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 and the phase current of one phase to adjust the current of the charge and discharge circuit, thereby realizing mutual charging and discharging between the power battery and the energy storage element, improving the heating capacity of the power battery, reducing capacity loss, and being able to accurately control the current.

[0004] To achieve the above-mentioned objectives, the present application provides the following technical solutions: 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 connected in sequence; the control method comprises: 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 in the three-phase motor, and the power battery are connected in sequence to form a charge and discharge circuit for the power battery; obtaining a target current of the power battery and a phase current of a first-phase winding in the three-phase motor, the first-phase winding being a winding in the three-phase motor connected to the inverter in the charge and discharge circuit; obtaining a duty cycle of a control pulse of a first-phase bridge arm in the inverter connected to the first-phase winding based on the target current and the phase current, and controlling the first-phase bridge arm based on the duty cycle to adjust the current of the charge and discharge circuit.

[0005] In one embodiment of the present 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 and the phase current includes: obtaining the current to be adjusted based on the target current and the phase current; 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 the present application, obtaining the current to be adjusted based on the target current and the phase current includes: performing proportional-integral adjustment on the phase current to obtain a current compensation term; calculating the target current minus the phase current and adding the current compensation term to obtain the current to be adjusted.

[0007] In one embodiment of the present application, before obtaining the target current of the power battery and the phase current of the first phase winding in the three-phase motor, it includes: controlling the entire vehicle to be in neutral gear, 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 the present 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 connected in sequence to form a charge and discharge circuit of the power battery, then controlling the three-phase motor to rotate to an angle position corresponding to the third of 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 connected in sequence to form a charge and discharge circuit of the power battery, then controlling the three-phase motor to rotate to an angle position corresponding to the second of 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 connected in sequence to form a charge and discharge circuit of the power battery, then controlling the three-phase motor to rotate to an angle position corresponding to the first of the three-phase motor.

[0009] In one embodiment of the present application, the control of 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 in the three-phase motor and the power battery are connected in sequence to form a charge and discharge circuit of the power battery, includes: controlling the first switch module and the third switch module to be turned off, and the second switch module to be turned on; controlling the first-phase bridge arm in the inverter so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Boost circuit to achieve discharge of the power battery; controlling the first-phase bridge arm in the inverter so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Buck circuit to achieve charging of the power battery.

[0010] In one embodiment of the present application, the first-phase bridge arm in the inverter is controlled so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Boost circuit, including: controlling the first switch tube in the upper bridge arm of the first-phase bridge arm in the inverter to turn off, so that the diode in parallel with the first switch tube, 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.

[0011] In one embodiment of the present application, the first-phase bridge arm in the inverter is controlled so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Buck buck circuit, including: controlling the first switch tube in the upper bridge arm of the first-phase bridge arm in the inverter to be turned on so that the first switch tube, the first phase winding connected to the first-phase bridge arm, and the second-phase winding of the three-phase motor form a Buck buck circuit.

[0012] As a second aspect of the present application, the present application also provides a 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 motor winding, the second switch module and the power battery are connected in sequence; the motor controller heating system also includes a controller, which is used to: control the conduction state of the first switch module, the second switch module and the inverter, so that the energy storage element, the inverter, the three-phase motor and the power battery are connected in sequence to form a charge and discharge circuit of the power battery; obtain the target current of the power battery and the phase current of the first phase winding in the three-phase motor, the first phase winding is the winding in the three-phase motor connected to the inverter in the charge and discharge circuit; 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 and the phase current, and control the first phase bridge arm according to the duty cycle to adjust the current of the charge and discharge circuit.

[0013] As a third aspect of the present application, the present application also provides a vehicle, comprising: the above-mentioned motor controller heating system.

[0014] The present application provides 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 connected in sequence; a charge and discharge circuit of the power battery is formed by controlling the second switch module and the third switch module; 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 two-phase windings in the three-phase motor are connected in sequence. and the power batteries are connected in sequence to form a charge and discharge circuit of the power battery; the target current of the power battery and the phase current of the first phase winding in the three-phase motor are obtained; 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 and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charge and discharge circuit. The conduction state of each switch tube in the first phase bridge arm can be controlled according to the duty cycle, and then the operation time of the charging circuit and the discharging circuit can be adjusted, so as to realize mutual charging and discharging between the power battery and the energy storage element, improve the heating capacity of the power battery, reduce the capacity loss, and accurately control the current. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0016] Figure 1 A schematic structural diagram of a motor controller heating system provided in an embodiment of the present application.

[0017] Figure 2 A flow chart of a control method for a motor controller heating system provided in an embodiment of the present application.

[0018] Figure 3 A circuit diagram of a motor controller heating system provided in an embodiment of the present application.

[0019] Figure 4 Schematic diagram of the equivalent motor drive circuit of the motor controller heating system provided in an embodiment of the present application.

[0020] Figure 5 Schematic diagram of the charge and discharge circuit of the motor controller heating system provided in an embodiment of the present application.

[0021] Figure 6 Schematic diagram of power battery discharge of the motor controller heating device provided in an embodiment of the present application.

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

[0023] Figure 8 This is an example diagram of the control method of the motor controller heating system provided in an embodiment of the present application.

[0024] Figure 9 Schematic diagram of charge and discharge current regulation of the motor controller heating system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The embodiments of the present application provide a motor controller heating system, a control method thereof, and a vehicle. By controlling the second switch module and the third switch module to form a charge and discharge circuit for the power battery, and adjusting the duty cycle of the control pulse according to the target current and the phase current of one phase to adjust the current of the charge and discharge circuit, 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 capacity loss, and accurately control the current.

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] New energy vehicles face challenges with charging difficulties, low discharge efficiency, and reduced cycle life in low-temperature conditions. This often requires heating the battery before operation. Existing technologies require connecting the battery to the neutral point of the motor to achieve heating, requiring significant modifications to the motor and resulting in high costs.

[0028] The technical solution of the embodiment of the present application is applicable to the application scenario of heating and discharging the power battery in new energy vehicles. The embodiment of the present application provides a 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 the power battery are connected in sequence.

[0029] When the first and third switch modules are off and the second switch module is on, 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 charge-discharge circuit for the power battery. By adjusting the duty cycle of the first-phase bridge arm of the inverter, the charge-discharge circuit can be regulated, 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 bridge arm of the inverter, the control signal controlling the motor rotation can be adjusted, thereby achieving motor driving force regulation.

[0031] Figure 1 FIG. 1 is a schematic diagram of a motor controller heating system according to an embodiment of the present 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 end of the inverter 10 is connected to the first end of the power battery C via the third switch module 14, and the second end of the inverter 10 is connected to the second end of the power battery C. The first end of the first phase winding L1 of the three-phase motor 11 is connected to the midpoint of the first phase bridge arm of the inverter 10, the first end of the second phase winding L3 of the three-phase motor 11 is connected to the midpoint of the second phase bridge arm of the inverter 10 via the first switch module 12, and the first end of the third phase winding L2 of the three-phase motor 11 is connected to the midpoint of the third phase bridge arm of the inverter 10 via the first switch module 12. The first end of the second phase winding L3 of the three-phase motor 11 is also connected to the first end of the power battery C via the second switch module 13. The second end of the first phase winding L1, the second end of the second phase winding L3, and the second end of the second phase winding L3 of the three-phase motor 11 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 can be one of the other two phase windings different from the first-phase winding, and the third-phase winding can be the other phase winding of the other two phase windings. In the embodiment of the present application, the first-phase winding is a U-phase winding, the second-phase winding is a W-phase winding, and the third-phase winding is a V-phase winding. The first-phase winding, the second-phase winding, and the third-phase winding in the three-phase motor are connected to the midpoints of the first-phase bridge arm, the second-phase bridge arm, and the third-phase bridge arm of the inverter, respectively.

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

[0034] The motor controller heating system provided in the embodiment of the present application further includes a controller, wherein the controller is configured to: Controlling the conduction states of the first switch module, the second switch module, and the inverter so that the energy storage element, the inverter, two-phase windings in the three-phase motor, and the power battery are connected in sequence to form a charge and discharge circuit for the power battery; Obtaining a target current of the power battery and a phase current of a first phase winding in the three-phase motor, where the first phase winding is a winding in the three-phase motor connected to the inverter in the charge-discharge 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 and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charge and discharge circuit.

[0035] Among them, the controller controls the first switch module 12 and the third switch module 14 to be turned off. After the second switch module 13 is closed, the power battery, the energy storage element, the first phase bridge arm of the inverter, the first phase winding and the second phase winding of the three-phase motor form a charge and discharge circuit of the power battery.

[0036] Further, the target current of the power battery and the phase current of the first phase winding in the three-phase motor are acquired. The target current of the power battery is the maximum charging and discharging current that the power battery can withstand, and the size of the target current can be determined according to the actual temperature rising effect. The phase current of the first phase winding in the three-phase motor can be detected by arranging a current sensor on the connection line between the first phase winding in the three-phase motor and the first phase bridge arm of the inverter. Since the first switch module is disconnected, the second phase bridge arm and the third phase bridge arm in the inverter are disconnected from the three-phase motor, and only the first phase bridge arm of the inverter is connected to the charging and discharging circuit. In this way, the duty cycle of the control pulse of the first phase bridge arm in the inverter connected to the first phase winding can be adjusted according to the target current and the phase current, and the on and off time of the first switch tube Q1 and the fourth switch tube Q4 in the upper bridge arm and the lower bridge arm of the first phase bridge arm can be controlled according to the duty cycle, so that the current of the charging and discharging circuit can be accurately controlled, and the power loss can be reduced.

[0037] The motor controller heating system is more specifically controlled by the control method described below.

[0038] Based on the above motor controller heating system, the motor controller heating system control method provided by the embodiments of the present application is as shown in Figure 2 The motor controller heating system control method includes the following steps: 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 in the three-phase motor and the power battery are connected in sequence to form a charging and discharging circuit of the power battery.

[0039] The first switch module is controlled to be disconnected, which disconnects the connection between the second phase bridge arm of the inverter and the second phase winding in the three-phase motor, and the connection between the third phase bridge arm of the inverter and the third phase winding in the three-phase motor. The second module is controlled to be disconnected, which disconnects the direct connection between the first end of the inverter and the first end of the power battery. The third switch module is controlled to be conductive, so that the second phase winding in the three-phase motor is directly connected to the first end of the power battery. In this way, the energy storage element, the inverter, the two phase windings in the three-phase motor and the power battery are connected in sequence to form a charging and discharging circuit of the power battery. Subsequently, the charging and discharging circuit can be controlled to realize the mutual charging and discharging between the power battery and the energy storage element.

[0040] Step S12: acquiring the target current of the power battery and the phase current of the first phase winding in the three-phase motor, the first phase winding being the winding in the three-phase motor connected to the inverter in the charging and discharging circuit.

[0041] The target current of the power battery is the maximum charge and discharge current that the power battery can withstand. The target current size can be determined based on the actual temperature rise effect. The phase current of the first phase winding in the three-phase motor is the actual current in the charge and discharge circuit. A current sensor can be set on the connection line between the first phase winding in 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. Subsequently, the actual current in the charge and discharge circuit can be adjusted according to the difference between the target current of the power battery and the phase current of the first phase winding in the three-phase motor. This can accurately control the charge and discharge current of the power battery and ensure the stability of the charge and discharge current of the power battery.

[0042] Step S13: Obtaining a duty cycle of a control pulse of a first phase bridge arm in the inverter connected to the first phase winding according to the target current and the phase current, and controlling the first phase bridge arm according to the duty cycle to adjust the current of the charge and discharge circuit.

[0043] In an embodiment of the present application, a control pulse of the first-phase bridge arm of the inverter can be used to control the conduction state of the first switching tube of the upper bridge arm and the fourth switching tube of the lower bridge arm in the first-phase bridge arm, thereby causing the circuit formed by the sequential connection of the energy storage element, the inverter, the two-phase windings of the three-phase motor, and the power battery to function as a Boost circuit for discharging the power battery, or a Buck circuit for discharging into the power battery. The duty cycle of the control pulse of the first-phase bridge arm of the inverter connected to the first-phase winding is obtained based on the target current and the phase current. Based on this duty cycle, the on- and off-times of the first and fourth switching tubes in the first-phase bridge arm during a cycle can be controlled to regulate the current in the charge-discharge circuit.

[0044] The control method of the motor controller heating system of the embodiment of the present application forms a charge and discharge circuit of 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 and the phase current of one phase to adjust the current of the charge and discharge circuit. It can realize mutual charging and discharging between the power battery and the energy storage element, improve the heating capacity of the power battery, reduce capacity loss, and can accurately control the current.

[0045] The motor controller heating system of the embodiment of the present application can work in the motor drive mode or the heating mode, that is, to heat and charge the power battery. Therefore, it is necessary to first determine the working requirements of the motor controller heating system. If the power battery needs to be heated and charged, the vehicle needs to be adjusted accordingly to facilitate the motor controller heating system to enter the power battery heating and charging state. Based on this, before step S11, the whole vehicle is controlled to be in neutral gear, and the three-phase motor is controlled to turn to a preset angle position; the inverter is controlled to work in pulse heating mode. The whole vehicle is in neutral gear to ensure that the three-phase motor can rotate. Then the three-phase motor is pre-positioned, that is, the three-phase motor is controlled to turn to a preset angle position to ensure zero torque output of the three motors. The motor controller has torque mode, speed mode, pulse heating mode, etc. During pulse heating, the pulse heating mode is switched.

[0046] The preset angle is set as needed, and the two windings in the three-phase motor connected to the charge and discharge circuit are related. Take the first phase, second phase and third phase of the three-phase motor as an example, which are U phase, W phase and V phase respectively. 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 connected in sequence to form the charge and discharge circuit of the power battery, 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 UW phase windings of the three-phase motor and the power battery are connected in sequence to form the charge and discharge circuit of the power battery, the preset angle is 120°.

[0047] 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 the power battery's charge and discharge circuit, the three-phase motor is controlled to rotate to an angular position corresponding to the second phase of 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 the power battery's charge and discharge circuit, the preset angle is 240°.

[0048] 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 charge-discharge circuit for the power battery, the three-phase motor is controlled to rotate to an angular position corresponding to the first phase of 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 V-phase winding and the power battery are sequentially connected to form a charge-discharge circuit for the power battery, the preset angle is 0°.

[0049] The specific circuit of the motor controller heating system is shown in Figure 3, the first switch module includes a first control switch K4. The first end of the first control switch K4 is connected to the midpoint of the second phase bridge arm in the inverter, and the second end 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 controlled to be disconnected from the second phase winding of the three-phase motor in the pulse heating mode. The first switch module also includes a second control switch K5, the first end of the second control switch K5 is connected to the midpoint of the third phase bridge arm in the inverter, and the second end 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 controlled to be disconnected from the third phase winding of the three-phase motor in the pulse heating mode.

[0050] The motor controller heating system also includes: a first current sensor A1 and a second current sensor A2, wherein 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 charge and discharge circuit. If the second current sensor A2 is connected to the second switch module away from the second phase winding of the three-phase motor, then when the motor controller heating system operates in the pulse heating mode, the second current sensor A2 is used to detect the current of the charge and discharge circuit, and the current detected by it 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.

[0051] The second switch module includes a third control switch K3. A first terminal of the third control switch K3 is connected to the first terminal of the power battery C, and a second terminal of the third control switch K3 is connected to the second-phase winding L3 of the three-phase motor. When the motor controller heating system operates in pulse heating mode, the third control switch K3 is turned on to connect the second-phase winding of the three-phase motor to the first terminal of the power battery, thereby forming a charge-discharge circuit for the power battery. When the motor controller heating system operates in other modes, the second switch module is turned off to disconnect the second-phase winding of the three-phase motor from the first terminal of the power battery, enabling the motor controller heating system to form a motor drive circuit.

[0052] The third switch module includes: a fourth control switch K1, a fifth control switch K2, and a first resistor R1; the first end of the fourth control switch K1 is connected to the first end of the power battery C, the second end of the fourth control switch K1 is connected to the first end of the inverter, the first end of the fifth control switch K2 is connected to the first end of the power battery C, and the second end of the fifth control switch K2 is connected to the first end of the inverter via 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. When the motor controller heating system operates in other modes, the energy storage element C1 is pre-charged to prevent damage to the device caused by sudden current changes in the motor drive circuit.

[0053] See also 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 operate normally. First, the fifth control switch K2 is turned on to pre-charge the energy storage element C1. Then, the fourth control switch K1 is turned on, and the fifth control switch is turned off. The motor drive circuit drives the three-phase motor to operate normally.

[0054] When the first switch module and the third switch module are disconnected and the second switch module is closed, that is, the first control switch K4, the second control switch K5, the fourth control switch K1 and the fifth control switch K2 are disconnected 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 a charge and discharge circuit for the power battery. Figure 5 As shown, the first end of the power battery C is connected to the midpoint of the first phase bridge arm in the inverter through 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 middle connection point between the upper bridge arm and the lower bridge arm 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 through the first switch tube Q1. The midpoint of the first phase bridge arm is connected to the other end of the energy storage element C1 and the second end of the power battery C through the fourth switch tube Q4. The first end of the power battery C is the positive electrode of the power battery C, and the second end of the power battery C is the negative electrode of the power battery C. The energy storage element is preferably a capacitor. At this time, each switch tube in the second phase bridge arm and the third phase bridge arm of the inverter is in the off state.

[0055] In this embodiment, one phase of a three-phase motor is connected to a power battery via a control switch, while another phase is connected to a switching transistor in an inverter. This allows AC heating of the power battery without any modifications to the three-phase motor or the power battery. Furthermore, after the motor is pre-positioned, the three-phase motor can be kept stationary. While the common market practice is to connect the motor's neutral point to the battery via a relay, this embodiment does not require any modifications to the motor.

[0056] In this embodiment of the present application, 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 controlled to be disconnected, and the fifth control switch K2 can be controlled to be closed to pre-charge the energy storage element C1 and equalize the voltage across the power battery and the energy storage element. The first and third switch modules are then controlled to be disconnected, and the second switch module is closed, so that the energy storage element C1, the inverter, the three-phase motor, and the power battery C form a power battery charge and discharge circuit.

[0057] By further controlling the first phase bridge arm in the inverter that is not connected to the first switch 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.

[0058] In an embodiment of the present application, the switching between the Boost circuit and the Buck circuit is achieved by cyclically controlling the on and off of the first switch tube Q1 in the first phase bridge arm. When the first switch tube Q1 is turned on, the motor winding is charged, and the load is powered by the energy storage element C1. When the first switch tube Q1 is turned off, the diode connected in parallel with the first switch tube Q1 is turned on, and the phase current cannot change suddenly. Therefore, the inductive current is supplied to the load and the capacitor through the diode. The load is the three-phase motor and the internal equivalent resistance of each device. In the Buck-Boost circuit, the charging and discharging process of the capacitor as the energy storage element C1 will produce certain losses: the capacitor is not an ideal component, and there is an equivalent series resistance (ESR) inside it. When current flows through the capacitor, the ESR will induce Joule heat, resulting in energy loss. During the charging and discharging process of a capacitor, the injection and release of charge will generate energy loss (dielectric loss) due to dielectric polarization. Leakage current, ripple, etc. will also cause energy loss, resulting in less capacitor discharge energy and a slow decay of the current. A PID adjustment is performed to compensate for the deviation between the actual value and the demand value and added to the demand current to ensure that the current remains stable and no longer decays.

[0059] In the embodiment of the present application, when discharging the power battery, the first phase bridge arm in the inverter is optionally controlled so that the first phase bridge arm and the two-phase windings in the three-phase motor form a Boost circuit to achieve the discharge of the power battery. 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 electrode of power battery C, passes 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, and returns to the negative electrode of power battery C. Power battery C charges energy storage element C1 through this boost circuit.

[0060] When the energy storage element charges the power battery, optionally, the first phase bridge arm in the inverter is controlled so that the first phase bridge arm and the two-phase windings in the three-phase motor form a Buck step-down circuit to charge the power battery. Figure 7 , controlling the first switching transistor in the upper bridge arm of the first-phase bridge arm in the inverter to conduct, so that the first switching transistor, 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. Current flows from the first end of the energy storage element, sequentially through the inverter and the first switching transistor, the first-phase winding of the three-phase motor, the second-phase winding of the three-phase motor, the positive electrode of the power battery, and the negative electrode of the power battery, returning to the second end of the energy storage element. Energy storage element C1 charges power battery C through this Buck step-down circuit.

[0061] In this way, the battery charge and discharge current is controlled to a sinusoidal current by boosting and lowering the voltage, achieving AC heating of the power battery. By adjusting the on and off times of the switches in the first-phase bridge arm of the inverter, the charge and discharge current of the power battery can be regulated. Adjusting the on and off times of the switches in the first-phase bridge arm is equivalent to adjusting the duty cycle of the control pulses in the first-phase bridge arm.

[0062] To accurately obtain the duty cycle of the control pulses of the first phase bridge arm of the inverter, in an embodiment of the present application, a current to be adjusted is optionally obtained based on the target current and the phase current. Proportional-integral adjustment is performed based on the current to be adjusted to obtain the duty cycle of the control pulses of the first phase bridge arm of the inverter connected to the first phase winding. The current to be adjusted is the portion of current that needs to be adjusted. The purpose of this embodiment of the present application is to ensure that the current in the charge-discharge circuit is consistent with the target current. The greater the difference between the target current and the phase current, the greater the resulting current to be adjusted. After obtaining the current to be adjusted, proportional-integral-differential (PID) adjustment is performed on the selected current. Specifically, proportional, integral, and differential adjustment are performed on the current to be adjusted based on the proportional coefficient, integral coefficient, and differential coefficient, respectively. This embodiment of the present application primarily performs proportional and integral adjustment. After PID adjustment of the current to be adjusted, the duty cycle of the control pulses 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 based on the obtained duty cycle, thereby achieving current regulation of the charge-discharge circuit.

[0063] Power batteries use sinusoidal charging and discharging currents. The current waveform formula is I=Asin(2*π*f*t). Here, A is the current amplitude, which must not exceed the maximum charge and discharge current the power battery can withstand; f is the current frequency, which must not exceed the frequency tolerated by the three-phase motor. A higher current amplitude improves the power battery's heating effect. A higher current frequency increases the charge and discharge frequency, resulting in better charging and discharging results. This frequency can be adjusted based on specific needs. A negative current I indicates capacitor discharge, charging the battery; a positive current I indicates battery discharge, charging the capacitor.

[0064] To precisely control the current in the charge-discharge circuit, it is necessary to accurately obtain the current to be adjusted. Based on this, in an embodiment of the present application, a proportional-integral adjustment is optionally performed on the phase current to obtain a current compensation term. The current to be adjusted is calculated by subtracting the phase current from the target current and adding the current compensation term. The current to be adjusted is primarily the difference between the target current and the phase current. To improve the accuracy of current regulation, an additional current compensation term is added in this embodiment of the present application.

[0065] In an embodiment of the present 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 poor control effect. Therefore, a current compensation term is added to compensate for the negative impact of this attenuation.

[0066] Taking the U-phase winding of the three-phase motor as an example, connected to the midpoint of the first bridge arm of the inverter, the W-phase of the three-phase motor as an example, connected to the midpoint of the second bridge arm of the inverter through the first control switch, and connected to the positive pole of the power battery through the third control switch, and the V-phase of the three-phase motor as an example, the control method of the motor controller heating system of the embodiment of the present application is shown in FIG. Figure 8 ,include: Step 100: Put the vehicle into neutral gear.

[0067] Putting the vehicle in neutral can ensure that the three-phase motor can rotate, facilitating the subsequent AC charging and discharging of the power battery.

[0068] Step 101: Pre-positioning the motor.

[0069] Rotate the three-phase motor's rotor to 120° to ensure zero torque output. Disconnect the V and W phases, and connect the W phase to the power battery. Control the U and W phases to form a loop. The three-phase motor will not rotate, so only the U phase current needs to be controlled.

[0070] Step 102: Switch to pulse heating mode.

[0071] The inverter has torque mode, speed mode, and pulse heating mode. During 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, and the third control switch K3 is closed. This forms a charge and discharge 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.

[0072] Step 103: Boost the battery to charge the capacitor.

[0073] The first switching transistor in the upper bridge arm of the first phase bridge arm of the inverter is controlled to turn off, so that the diode connected in parallel with the first switching transistor, 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.

[0074] Step 104: The Buck capacitor charges the battery.

[0075] The first switch in the upper arm of the first phase bridge arm of the 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 circuit. The energy storage element charges the power battery through this Boost circuit.

[0076] In step 103 and step 104, the duty cycle of the control pulse of the first phase bridge arm in the inverter is adjusted to adjust the charging and discharging current of the power battery. Figure 9 , obtain the target current of the power battery and the U-phase current in the three-phase motor, perform PID2 adjustment on the U-phase current to obtain the current compensation term; calculate the target current minus the U-phase current and add the current compensation term to obtain the current to be adjusted. Further perform PID1 adjustment based on the current to be adjusted to obtain the U-phase duty cycle, which is the U-phase duty cycle of the control pulse of the first-phase bridge arm in the inverter connected to the U-phase winding. Among them, PID1 adjustment and PID2 adjustment are both proportional-integral, and the only difference between the two is that the proportional coefficient and integral coefficient are different. According to the U-phase duty cycle, the conduction state of the first and fourth switching tubes in the first-phase bridge arm of the inverter can be adjusted, thereby realizing the regulation of the charging and discharging current of the power battery.

[0077] In the embodiment of the present application, when the second control switch K5 is disconnected, only the U and W phases are used to form a loop, which can ensure that the U and W phase currents are equal, the V phase current is 0, and the three-phase motor is pre-positioned to 120°. When the U phase current is controlled in this way, the three-phase motor outputs zero torque and the three-phase motor does not rotate. Without the second control switch K5, the second switch tube Q2 and the fifth switch tube Q5 are disconnected, but due to the effect of the diode, there is a V-phase diode freewheeling phenomenon in the inverter circuit, causing the capacitor voltage to increase. Adding the second control switch K5 relay and disconnecting the second control switch K5 eliminates the V-phase diode freewheeling loop, significantly reducing the capacitor voltage, that is, a small-capacity capacitor can meet the requirements.

[0078] The control method of the motor controller heating system of the embodiment of the present application uses existing power batteries, three-phase motors, and inverters. Only the inverter needs to be modified to achieve AC heating of the power battery, and the modification is small. Since only one phase bridge arm in the inverter is connected to the charge and discharge circuit, the diode freewheeling is reduced, so that the choice of capacitor capacity can be greatly reduced in terms of capacitor selection. It can ensure that after pre-positioning, the three-phase motor does not rotate, and has strong reliability. The buck-boost bidirectional step-up and step-down function is realized by using the three-phase motor and inverter. The power battery and capacitor are used as energy storage devices to charge and discharge each other, thereby improving the heating capacity and reducing the capacity loss. In addition, the current is well controllable and the control is precise.

[0079] An embodiment of the present application also provides a vehicle, comprising: the above-mentioned motor controller heating system.

[0080] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0081] The block diagrams of the devices, devices, equipment, 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 will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0082] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0083] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present 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.

[0084] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly illustrate the technical solutions and cannot be used to limit the scope of protection of the present application.

[0085] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example 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 a 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 in the three-phase motor, and the power battery are sequentially connected to form a charge and discharge circuit for the power battery; Obtaining a target current of the power battery and a phase current of a first phase winding in the three-phase motor, where the first phase winding is a winding in the three-phase motor connected to the inverter in the charge-discharge 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 and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charge and discharge circuit.

2. The method according to claim 1, characterized in that The step of obtaining a duty cycle of a control pulse of a first phase bridge arm in the inverter connected to the first phase winding according to the target current and the phase current includes: Acquire the current to be adjusted according to the target current and the phase current; Proportional-integral regulation is performed according to the current to be regulated to obtain a duty cycle of a control pulse of a first phase bridge arm in the inverter connected to the first phase winding.

3. The method according to claim 2, characterized in that The obtaining the current to be adjusted according to the target current and the phase current includes: Performing proportional-integral regulation on the phase current to obtain a current compensation term; The target current is calculated by subtracting the phase current and adding the current compensation term to obtain the current to be adjusted.

4. The method according to claim 1, wherein Before obtaining the target current of the power battery and the phase current of the first phase winding of the three-phase motor, the method includes: Controlling the vehicle to shift into neutral gear and controlling the three-phase motor to rotate to a preset angle position; The inverter is controlled to operate in a pulse heating mode.

5. The method according to claim 4, characterized in that The 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 connected in sequence to form a charge and discharge circuit of the power battery, then the three-phase motor is controlled to rotate to an angular position corresponding to the third phase of 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 connected in sequence to form a charge and discharge circuit of the power battery, then the three-phase motor is controlled to rotate to an angular position corresponding to the second phase of the three-phase motor; If the energy storage element, the inverter, the second phase winding, the third phase winding in the three-phase motor and the power battery are connected in sequence to form a charge and discharge circuit of the power battery, the three-phase motor is controlled to rotate to an angular position corresponding to the first of the three-phase motor.

6. The method according to claim 1, characterized in that The controlling 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, the two-phase windings of the three-phase motor, and the power battery are sequentially connected to form a charge and discharge circuit of the power battery includes: controlling the first switch module and the third switch module to be turned off, and the second switch module to be turned on; Controlling the first-phase bridge arm in the inverter so that the first-phase bridge arm and two-phase windings in the three-phase motor form a Boost circuit to discharge the power battery; The first-phase bridge arm in the inverter is controlled so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Buck step-down circuit to charge the power battery.

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

8. The method according to claim 6, characterized in that The controlling of the first-phase bridge arm in the inverter so that the first-phase bridge arm and the two-phase windings in the three-phase motor form a Buck step-down circuit includes: The first switch tube in the upper bridge arm of the first phase bridge arm in the inverter is controlled to be turned on, so that the first switch tube, 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: 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 winding, the second switch module, and a power battery are connected in sequence; The motor controller heating system further includes a controller configured to: 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 in the three-phase motor, and the power battery are sequentially connected to form a charge and discharge circuit for the power battery; Obtaining a target current of the power battery and a phase current of a first phase winding in the three-phase motor, where the first phase winding is a winding in the three-phase motor connected to the inverter in the charge-discharge 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 and the phase current, and the first phase bridge arm is controlled according to the duty cycle to adjust the current of the charge and discharge circuit.

10. A vehicle, characterized in that: The vehicle comprises: the motor controller heating system according to claim 9.

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