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 charge-discharge circuit 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; obtaining a 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 and the phase current, and controlling the first-phase bridge arm according to the duty cycle, so as to adjust the current of the charge-discharge circuit; and adjusting the duty cycle of the control pulse according to the target current and the phase current to adjust the current of the charge-discharge circuit, which can realize mutual charge-discharge 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.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle control, in particular to a motor controller heating system, a control method thereof and a vehicle. BACKGROUND

[0002] New energy vehicles have problems such as charging difficulty, low discharging efficiency and cycle life attenuation of power batteries under low temperature conditions, and usually need to heat the batteries before the power batteries work. In the prior art, the battery needs to be connected to the neutral point of the motor to realize the heating of the power battery. SUMMARY

[0003] Therefore, the present application provides 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 charging and discharging circuit of 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 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 can be improved, the capacity loss can be reduced, and the current can be accurately controlled.

[0004] In order to achieve the above purpose, the present application provides the following technical scheme: a control method of 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 state of the first switch module, the second switch module, the third switch module and the inverter, so that 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; 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 charging and discharging circuit; 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 charging and discharging circuit.

[0005] In an embodiment of the present application, 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, comprising: obtaining a to-be-adjusted current according to the target current and the phase current; performing proportional integral adjustment according to the to-be-adjusted current 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 an embodiment of the present application, the obtaining the to-be-adjusted current according to the target current and the phase current comprises: performing proportional integral adjustment on the phase current to obtain a current compensation term; and calculating the target current minus the phase current plus the current compensation term to obtain the to-be-adjusted current.

[0007] In an embodiment of the present application, before the obtaining the target current of the power battery and the phase current of the first phase winding of the three-phase motor, the method comprises: controlling the whole vehicle to be in a neutral gear, and controlling the three-phase motor to rotate to a preset angle position; and controlling the inverter to work in a pulse heating mode.

[0008] In an embodiment of the present application, the controlling the three-phase motor to rotate to the preset angle position comprises: 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 charge-discharge circuit of the power battery, then the three-phase motor is controlled to rotate to an angle 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 sequentially connected to form the charge-discharge circuit of the power battery, then the three-phase motor is controlled to rotate to an angle position corresponding to the second phase of the three-phase motor; and 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 the charge-discharge circuit of the power battery, then the three-phase motor is controlled to rotate to an angle position corresponding to the first phase of the three-phase motor.

[0009] In an embodiment of the present application, the controlling the on-off 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 the charge-discharge circuit of the power battery comprises: controlling the first switch module and the third switch module to be off and the second switch module to be on; controlling the first phase bridge arm in the inverter to form a Boost circuit with two phase windings of the three-phase motor to realize discharging of the power battery; and controlling the first phase bridge arm in the inverter to form a Buck circuit with two phase windings of the three-phase motor to realize charging of the power battery.

[0010] In an embodiment of the present application, the control of the first phase bridge arm in the inverter to make the first phase bridge arm and two phase windings in the three-phase motor form a Boost circuit comprises: controlling a first switch tube in the upper bridge arm of the first phase bridge arm in the inverter to be turned off, so that a diode connected in parallel with the first switch tube, the first phase winding connected with the first phase bridge arm, and a second phase winding of the three-phase motor form a Boost circuit.

[0011] In an embodiment of the present application, the control of the first phase bridge arm in the inverter to make the first phase bridge arm and two phase windings in the three-phase motor form a Buck circuit comprises: controlling a 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 with the first phase bridge arm, and a second phase winding of the three-phase motor form a Buck circuit.

[0012] As a second aspect of the present application, the present application further 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 a power battery are connected in sequence; the motor controller heating system further comprises a controller, the controller is configured 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-discharge circuit of the power battery; obtain 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 with the inverter in the charge-discharge circuit; obtain a 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 and the phase current, and control the first phase bridge arm according to the duty cycle to adjust the current of the charge-discharge circuit.

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

[0014] The application provides a control method of 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; a charging and discharging 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, two-phase windings in the three-phase motor and the power battery are sequentially connected to form the charging and discharging circuit of the power battery; a target current of the power battery and a phase current of a first-phase winding in the three-phase motor are acquired; the duty cycle of a control pulse of a first-phase bridge arm in the inverter connected with the first-phase winding is acquired according to the target current and the phase current, and the first-phase bridge arm is controlled according to the duty cycle, so as to adjust the current of the charging and discharging 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 that 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. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the provided drawings.

[0016] Figure 1 A structural schematic diagram of a motor controller heating system is provided for the embodiments of the present application.

[0017] Figure 2 A flowchart of a control method of a motor controller heating system is provided for the embodiments of the present application.

[0018] Figure 3 A circuit schematic diagram of a motor controller heating system is provided for the embodiments of the present application.

[0019] Figure 4 An equivalent motor driving circuit schematic diagram of a motor controller heating system is provided for the embodiments of the present application.

[0020] Figure 5 A charging and discharging circuit schematic diagram of a motor controller heating system is provided for the embodiments of the present application.

[0021] Figure 6 A power battery discharge schematic diagram of the motor controller heating device provided in the embodiment of the present application is shown.

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

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

[0024] Figure 9 A charge-discharge current adjustment schematic diagram of the motor controller heating system provided in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] The motor controller heating system and the control method thereof and the vehicle provided in the embodiments of the present application can realize mutual charge-discharge between the power battery and the energy storage element, improve the power battery heating capability, reduce the capability loss, and accurately control the current, by controlling the second switch module and the third switch module to form a charge-discharge loop of 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-discharge loop.

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

[0027] The new energy vehicle has problems such as charging difficulty, low discharging efficiency, and cycle life attenuation of the power battery under low temperature conditions, and usually needs to heat the battery before working. In the prior art, the battery needs to be connected to the neutral point of the motor to realize heating of the power battery, which greatly changes the motor and has high cost.

[0028] The technical solutions in the embodiments of the present application are suitable for the application scenario of heating and discharging the power battery in the new energy vehicle. The motor controller heating system provided in the embodiments of the present application comprises 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] The first switch module and the third switch module are turned off, and the second switch module is closed, so that the power battery, the energy storage element, the first phase bridge arm of the inverter and two phase windings of the three-phase motor form a charging and discharging circuit of 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, and the mutual charging and discharging between the power battery and the energy storage element can be realized.

[0030] The first switch module and the third switch module are closed, and the second switch module is turned off, so that the power battery, the energy storage element, the inverter and the three-phase motor form a motor driving circuit. By adjusting the duty cycle of each phase bridge arm of the inverter, the control signal for controlling the rotation of the motor can be adjusted, and then the driving force of the motor can be adjusted.

[0031] Figure 1 Fig. 1 shows a structure schematic diagram of a motor controller heating system provided by an embodiment of the present application. Figure 1 As shown in the figure, the motor controller heating system comprises 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. A first end of the inverter 10 is connected to a first end of a power battery C through the third switch module 14, and a second end of the inverter 10 is connected to a second end of the power battery C. A first end of a first phase winding L1 of the three-phase motor 11 is connected to a midpoint of a first phase bridge arm in the inverter 10, a first end of a second phase winding L3 of the three-phase motor 11 is connected to a midpoint of a second phase bridge arm in the inverter 10 through the first switch module 12, and a first end of a third phase winding L2 of the three-phase motor 11 is connected to a midpoint of a third phase bridge arm in the inverter 10 through 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 through the second switch module 13. A second end of the first phase winding L1, a second end of the second phase winding L3 and a second end of the third phase winding L3 of the three-phase motor 11 are connected to form a 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 the 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. The embodiment of the present application takes 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 phase winding, the second phase winding and the third phase winding in the three-phase motor are respectively connected to the midpoints of the first phase bridge arm, the second phase bridge arm and the third phase bridge arm in the inverter.

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

[0034] The motor controller heating system provided by the embodiment of the present application further comprises a controller, which is configured to:

[0035] control 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 sequentially connected to form a charge-discharge circuit of the power battery;

[0036] obtain 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-discharge circuit;

[0037] obtain 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 control the first phase bridge arm according to the duty cycle to adjust the current of the charge-discharge circuit.

[0038] The controller controls the first switch module 12 and the third switch module 14 to be turned off, and 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-discharge circuit of the power battery.

[0039] 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.

[0040] The motor controller heating system is more specifically controlled by the control method described below.

[0041] 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 follows: Figure 2 As shown in the figure, the motor controller heating system control method 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 in the three-phase motor and the power battery are connected in sequence to form a charging and discharging circuit of the power battery.

[0043] 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.

[0044] 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.

[0045] 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 is the actual current in the charging and discharging circuit. A current sensor can be arranged 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. The actual current in the charging and discharging 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, so that the current for charging and discharging the power battery can be accurately controlled, and the charging and discharging current of the power battery can be stabilized.

[0046] Step S13: Obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter connected with 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 charging and discharging circuit.

[0047] In the embodiment of the present application, the control pulse of the first phase bridge arm in the inverter can control the conduction state of the first switch tube in the upper bridge arm and the fourth switch tube in the lower bridge arm, so as to make the circuit formed by the energy storage element, the inverter, the two phase windings in the three-phase motor and the power battery in sequence to be a Boost circuit for discharging the power battery or a Buck circuit for discharging the power battery. According to the target current and the phase current, the duty cycle of the control pulse of the first phase bridge arm in the inverter connected with the first phase winding is obtained, and according to the duty cycle, the conduction and turn-off time of the first switch tube and the fourth switch tube in the first phase bridge arm in a period can be controlled, so as to adjust the current of the charging and discharging circuit.

[0048] The control method of the motor controller heating system in the embodiment of the present application forms the charging and discharging circuit of the power battery by controlling the second switch module and the third switch module, 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 charging and discharging circuit, and can 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.

[0049] The motor controller heating system of the embodiment of the present application can work in a motor driving mode and can also work in a heating mode, i.e. heating and charging and discharging the power battery. Therefore, the working requirement of the motor controller heating system needs to be determined first. If the power battery needs to be heated and charged and discharged, the vehicle needs to be adjusted accordingly to facilitate the motor controller heating system to enter the state of heating and charging and discharging the power battery. 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 a pulse heating mode. The whole vehicle in neutral gear can ensure that the three-phase motor can rotate. Then, the three-phase motor is pre-positioned, i.e. the three-phase motor is controlled to turn to a preset angle position, which can ensure that the three-phase motor outputs zero torque. The motor controller has torque mode, speed mode, pulse heating mode, etc. When pulse heating, the pulse heating mode is switched.

[0050] The preset angle is set according to the requirement and is related to two windings in the three-phase motor connected in the charging and discharging circuit. Taking the first phase, the second phase and the third phase in the three-phase motor as U phase, W phase and V phase respectively as an example. If the energy storage element, the inverter, the first phase winding and the second phase winding in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, the three-phase motor is controlled to turn to the angle position corresponding to the third phase of the three-phase motor. That is, if the V phase in the three-phase motor is disconnected, the energy storage element, the inverter, the U and W phase windings in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, and the preset angle is 120°.

[0051] If the energy storage element, the inverter, the first phase winding and the third phase winding in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, the three-phase motor is controlled to turn to the angle position corresponding to the second phase of the three-phase motor. That is, if the W phase in the three-phase motor is disconnected, the energy storage element, the inverter, the U and V phase windings in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, and the preset angle is 240°.

[0052] If the energy storage element, the inverter, the second phase winding and the third phase winding in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, the three-phase motor is controlled to turn to the angle position corresponding to the first phase of the three-phase motor. That is, if the U phase in the three-phase motor is disconnected, the energy storage element, the inverter, the V and W phase windings in the three-phase motor and the power battery are connected in sequence to form the charging and discharging circuit of the power battery, and the preset angle is 0°.

[0053] The specific circuit of the motor controller heating system can be referred to Figure 3The first switch module comprises a first control switch K4. A first end of the first control switch K4 is connected to a midpoint of a second phase bridge arm in the inverter, and a second end of the first control switch K4 is connected to a second phase winding L3 of the three-phase motor. By arranging 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 in the pulse heating mode. The first switch module further comprises a second control switch K5. A first end of the second control switch K5 is connected to a midpoint of a third phase bridge arm in the inverter, and a second end of the second control switch K5 is connected to a third phase winding L2 of the three-phase motor. By arranging 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 in the pulse heating mode.

[0054] The motor controller heating system further comprises a first current sensor A1 and a second current sensor A2. The first current sensor A1 is connected between a midpoint of a first bridge arm of the inverter and a first phase winding L1 of the three-phase motor. The second current sensor A2 is connected between the first control switch and a second phase winding L3 of the three-phase motor. The first current sensor A1 is used to detect a 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 current sensor A2 is connected to the second switch module away from the second phase winding of the three-phase motor, the second current sensor A2 is used to detect the current of the charging and discharging circuit when the motor controller heating system works in the pulse heating mode, and the current detected by the second current sensor A2 is consistent with the first current sensor A1. When the motor controller heating system works 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 comprises a third control switch K3. A first end of the third control switch K3 is connected to a first end of the power battery C, and a second end of the third control switch K3 is connected to a second phase winding L3 of the three-phase motor. The third control switch K3 is turned on when the motor controller heating system works in the pulse heating mode, and is used to connect the second phase winding of the three-phase motor to the first end of the power battery to form a charging and discharging circuit of the power battery. When the motor controller heating system works in other modes, the second switch module is turned off, and is used to disconnect the second phase winding of the three-phase motor from the first end of the power battery, so that the motor controller heating system can form a motor driving circuit.

[0056] The third switch module comprises a fourth control switch K1, a fifth control switch K2 and a first resistor R1; a first end of the fourth control switch K1 is connected with a first end of the power battery C, a second end of the fourth control switch K1 is connected with a first end of the inverter, a first end of the fifth control switch K2 is connected with the first end of the power battery C, and a second end of the fifth control switch K2 is connected with the first end of the inverter through the first resistor R1. When the motor controller heating system works in other modes, the fourth control switch K1 is closed, so that the motor controller heating system can form a motor driving circuit to drive the motor to work normally. The fifth control switch K2 and the first resistor R1 constitute a pre-charging circuit, and the energy storage element C1 is pre-charged when the motor controller heating system works in other modes, so as to prevent the device from being damaged due to current mutation in the motor driving circuit.

[0057] Referring to Figure 4 , when the first switch module is closed and the second switch module is disconnected, the power battery C, the energy storage element C1, the inverter and the three-phase motor form a motor driving circuit to drive the three-phase motor to work normally. First, the fifth control switch K2 is controlled to be turned on, and the energy storage element C1 is pre-charged, then the fourth control switch K1 is turned on, and the fifth control switch is controlled to be disconnected, and the three-phase motor is driven to work normally through the motor driving circuit.

[0058] 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 power battery charging and discharging circuit. As shown in Figure 5 , the first end of the power battery C is connected with 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 intermediate connection point of 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 with one end of the energy storage element C1 through the first switch tube Q1, and the midpoint of the first phase bridge arm is connected with 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 in the inverter is in the off state.

[0059] The embodiment of the present application connects one phase of the three-phase motor to the power battery through a control switch, and adds a control switch to connect the switch tube in the inverter to another phase, so that the alternating current heating of the power battery can be realized without any change to the three-phase motor and the power battery, and the three-phase motor can be rotated without rotation after the motor is positioned. The common market method is to connect the battery through a relay from the neutral point of the motor, and the embodiment of the present application does not need to change the motor.

[0060] In the embodiment of the present application, before the inverter is controlled to work in the pulse heating mode, the first control switch K4, the second control switch K5, the third control switch K3 and the fourth control switch K1 are controlled to be opened, and the fifth control switch K2 is controlled to be closed, so as to pre-charge the energy storage element C1, so that the voltage across the power battery is equal to the voltage across the energy storage element. Then the first switch module and the third switch module are controlled to be opened, and the second switch module is controlled to be closed, so as to form a charge-discharge circuit of the power battery formed by the energy storage element C1, the inverter, the three-phase motor and the power battery C.

[0061] Further, by controlling the first phase bridge arm in the inverter which is not connected to the first switch module, a Boost circuit is first formed to charge the energy storage element with the power battery, and then a Buck circuit is formed to charge the battery with the energy storage element, so as to realize the heating and discharging of the power battery C.

[0062] In the embodiment of the present application, the conduction and turn-off of the first switch tube Q1 in the first phase bridge arm are controlled in a cycle, so as to switch the Boost circuit and the Buck circuit. 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 be suddenly changed, so the inductance current supplies power 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 cause a certain loss: the capacitor is not an ideal element, and there is an equivalent series resistance (ESR) inside. When the current flows through the capacitor, the ESR will cause Joule heat, resulting in energy loss. During the charging and discharging process of the capacitor, the injection and release of electric charge will cause energy loss (dielectric loss) due to dielectric polarization; leakage current, ripple and other factors will also cause energy loss, so that the discharge energy of the capacitor becomes less, and the current slowly decays; the actual value and the required value are adjusted by a PID adjustment with a deviation as compensation added to the required current, so that the current can remain stable and not decay.

[0063] In the embodiments of the present application, when discharging the power battery, 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 discharging of the power battery. Referring to Figure 6 The first switch Q1 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, 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 current flows out from the positive pole of the power battery C, sequentially 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 pole of the power battery C. The power battery C is charged to the energy storage element C1 through the Boost circuit.

[0064] When the energy storage element charges the power battery, the first phase bridge arm in the inverter is controlled to form a Buck circuit with two phase windings in the three-phase motor, so as to realize charging of the power battery. Referring to Figure 7 The first switch 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, 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 current flows out from the first end of the energy storage element, sequentially passes 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 pole of the power battery, and the negative pole of the power battery, and returns to the second end of the energy storage element. The energy storage element C1 is charged to the power battery C through the Buck circuit.

[0065] In this way, the battery charging and discharging current is a sine wave current through the boost and buck control, and the power battery AC heating is realized. By adjusting the turn-on and turn-off time of each switch in the first phase bridge arm in the inverter, the current of the power battery charging and discharging can be adjusted. Adjusting the turn-on and turn-off time of each switch in the first phase bridge arm is equivalent to adjusting the duty cycle of the control pulse of the first phase bridge arm.

[0066] In order to accurately obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter, in the embodiment of the present application, optionally, a to-be-adjusted current is obtained according to the target current and the phase current; the duty cycle of the control pulse of the first phase bridge arm in the inverter connected with the first phase winding is obtained by proportion-integral adjustment according to the to-be-adjusted current. The to-be-adjusted current is the part of the current that needs to be adjusted. The purpose of the embodiment of the present application is to make the current in the charge-discharge circuit consistent with the target current, and the greater the difference between the target current and the phase current, the greater the to-be-adjusted current obtained. After the to-be-adjusted current is obtained, the proportion-integral-differential (PID) adjustment is performed on the to-be-adjusted current, that is, the proportion, integral and differential adjustment is performed on the to-be-adjusted current according to the proportion coefficient, integral coefficient and differential coefficient, and the embodiment of the present application mainly performs proportion and integral adjustment. The duty cycle of the control pulse of the first phase bridge arm can be obtained after the PID adjustment of the to-be-adjusted current. The conduction state of each switch tube in the first phase bridge arm can be adjusted according to the obtained duty cycle, and then the adjustment of the current in the charge-discharge circuit is realized.

[0067] The power battery adopts sine current charging and discharging, and the current waveform formula is I=Asin(2*π*f*t), wherein A is the current amplitude, which cannot exceed the maximum charging and discharging current that the power battery can bear; f is the current frequency, which cannot exceed the frequency value that the three-phase motor can bear. The greater the current amplitude, the better the heating effect of the power battery, the higher the current frequency, the higher the charging and discharging frequency, and the better the charging and discharging effect. The actual demand can be adjusted according to the actual demand; the current I is negative, which is the capacitor discharging and charging the battery; the current I is positive, which is the power battery discharging and charging the capacitor.

[0068] In order to accurately control the current of the charge-discharge circuit, it is necessary to accurately obtain the to-be-adjusted current. Based on this, in the embodiment of the present application, optionally, the proportion-integral adjustment is performed on the phase current to obtain a current compensation term; the to-be-adjusted current is obtained by calculating the target current minus the phase current plus the current compensation term. The to-be-adjusted current is mainly the difference between the target current and the phase current, and the current compensation term is added to improve the accuracy of current adjustment.

[0069] In the embodiment of the present application, during the battery heating process, the boost circuit is used to charge the capacitor with the battery, and the buck circuit is used to charge the battery with the capacitor. In this process, the capacitor loss will cause the current to attenuate and the control effect to be poor, so the current compensation term is added to compensate for the negative effects caused by the attenuation.

[0070] The U-phase winding of the three-phase motor is connected with the midpoint of the first bridge arm of the inverter, the W-phase of the three-phase motor is connected with the midpoint of the second phase bridge arm of the inverter through the first control switch and connected with the positive pole of the power battery through the third control switch, and the V-phase of the three-phase motor is connected with the midpoint of the third bridge arm of the inverter through the second control switch. The control method of the motor controller heating system in the embodiment of the application is exemplified with reference to Figure 8 , comprising:

[0071] Step 100: The whole vehicle is hung in the neutral gear.

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

[0073] Step 101: Motor pre-positioning.

[0074] The rotor of the three-phase motor is turned to the 120° position to ensure zero torque output of the three-phase motor. The V-phase is disconnected, the W-phase is disconnected, and the W-phase is connected with the power battery. The U-phase and the W-phase form a loop, so the three-phase motor will not rotate, and therefore only the U-phase current needs to be controlled.

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

[0076] The inverter has torque mode, speed mode, pulse heating mode, etc. When pulse heating, the inverter is switched to pulse heating mode first. Specifically, 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 U-phase and W-phase windings of the three-phase motor and the power battery C form a power battery charging and discharging loop.

[0077] Step 103: Boosting the battery to charge the capacitor.

[0078] 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 with 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 the Boost circuit.

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

[0080] 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 with 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 the Boost circuit.

[0081] In step 103 and step 104, the duty cycle of the control pulse of the first phase bridge arm in the inverter is adjusted, so as to realize the adjustment of the power battery charging and discharging current. Figure 9 The target current of the power battery and the U-phase current in the three-phase motor are acquired, the U-phase current is subjected to PID2 adjustment to acquire a current compensation term, the target current minus the U-phase current plus the current compensation term is calculated to obtain a to-be-adjusted current. The to-be-adjusted current is further subjected to PID1 adjustment to obtain a U-phase duty cycle, and the U-phase duty cycle is the U-phase duty cycle of the control pulse of the first phase bridge arm in the inverter connected with the U-phase winding. The PID1 adjustment and the PID2 adjustment are both proportional integration, and the difference only lies in that the proportional coefficient and the integral coefficient of the two are different. According to the U-phase duty cycle, the conduction states of the first switch tube and the fourth switch tube in the first phase bridge arm in the inverter can be adjusted, so as to realize the adjustment of the power battery charging and discharging current.

[0082] In the embodiment of the application, when the second control switch K5 is disconnected, only the U and W phases are used to form a loop, the U and W phase currents can be ensured to be equal, the V phase current is 0, the three-phase motor is pre-positioned to 120°, and the three-phase motor outputs zero torque when the U phase current is controlled, so that the three-phase motor does not rotate. If the second control switch K5 is not added, the second switch tube Q2 and the fifth switch tube Q5 are disconnected, but due to the action of the diode, the V phase diode freewheeling phenomenon exists in the inverter loop, which causes the capacitor voltage to rise. Adding the second control switch K5 relay, when the second control switch K5 is disconnected, the V phase diode freewheeling loop no longer exists, and the capacitor voltage is greatly reduced, that is, a small-capacity capacitor can meet the requirements.

[0083] The control method of the motor controller heating system in the embodiment of the application only needs to change the existing power battery, three-phase motor and inverter, and only the inverter needs to be changed to realize the AC heating of the power battery, and the change is small. Since only one phase bridge arm in the inverter is connected to the charging and discharging loop, the diode freewheeling is reduced, the capacitor capacity selection can be greatly reduced in capacitor selection, the three-phase motor can be ensured not to rotate after pre-positioning, and strong reliability is achieved. The three-phase motor and the inverter are used to realize the buck-boost bidirectional step-up and step-down function, the power battery and the capacitor are used as energy storage devices, and mutual charging and discharging is realized to improve the heating capacity and reduce the power loss. The current controllability is good, and the control is accurate.

[0084] The embodiment of the application further provides a vehicle, which comprises the motor controller heating system.

[0085] The above describes the basic principles of the present application in combination with specific embodiments, but it should be noted that the advantages, benefits, effects and the like mentioned in the present application are only examples and are not limiting, and these advantages, benefits, effects and the like cannot be considered as necessary for each embodiment of the present application. In addition, the above specific details disclosed are only for the purpose of illustration and understanding, and are not limiting, and the above details do not limit the present application to be necessarily implemented with the above specific details.

[0086] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply the connection, arrangement, configuration shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have" and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0087] It should also be noted that in the devices, equipment and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions of the present application.

[0088] The above description of the disclosed aspects is provided so that any person skilled in the art can make or use the present application. Various modifications to these aspects will be 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 the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0089] It should be understood that the adjectives "first", "second", "third", "fourth", "fifth" and "sixth" used in the embodiments of the present application are only used for clearer description of the technical solutions, and cannot be used to limit the protection scope of the present application.

[0090] The above description has been given 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, changes, additions and sub-combinations thereof.

Claims

1. A control method of a motor controller heating system, characterized by, The motor controller heating system comprises 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; wherein a first end of the inverter is connected with a first end of the power battery through the third switch module, a second end of the inverter is connected with a second end of the power battery, a first end of a first phase winding of the three-phase motor is connected with a midpoint of a first phase bridge arm in the inverter, a first end of a second phase winding of the three-phase motor is connected with a midpoint of a second phase bridge arm in the inverter through the first switch module, a first end of a third phase winding of the three-phase motor is connected with a midpoint of a third phase bridge arm in the inverter through the first switch module, the first end of the second phase winding of the three-phase motor is also connected with the first end of the power battery through the second switch module, one end of the energy storage element is connected with the first end of the inverter, and the other end of the energy storage element is connected with the second end of the inverter; 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 sequentially connected to form a charge-discharge circuit 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 first phase winding being a winding in the three-phase motor connected with the inverter in the charge-discharge circuit; obtaining a 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 and the phase current, and controlling the first phase bridge arm according to the duty cycle to adjust the current of the charge-discharge circuit.

2. The method of claim 1, wherein, The method of obtaining the duty cycle of the control pulse of the first phase bridge arm in the inverter connected with the first phase winding according to the target current and the phase current comprises: obtaining a to-be-adjusted current according to the target current and the phase current; performing proportional integral adjustment on the to-be-adjusted current to obtain the duty cycle of the control pulse of the first phase bridge arm in the inverter connected with the first phase winding.

3. The method of claim 2, wherein, The method of obtaining the to-be-adjusted current according to the target current and the phase current comprises: performing proportional integral adjustment on the phase current to obtain a current compensation term; calculating the to-be-adjusted current by subtracting the phase current from the target current and adding the current compensation term.

4. The method of claim 1, wherein, Before the method of obtaining the target current of the power battery and the phase current of the first phase winding in the three-phase motor, the method comprises: controlling the whole vehicle to be in a neutral gear, and controlling the three-phase motor to turn to a preset angle position; controlling the inverter to work in a pulse heating mode.

5. The method of claim 4, wherein, The method of controlling the three-phase motor to turn to the preset angle position comprises: If the energy storage element, the inverter, the first phase winding, the second phase winding in the three-phase motor and the power battery are sequentially connected to form a charge-discharge circuit of the power battery, 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 in the three-phase motor and the power battery are sequentially connected to form a charge-discharge circuit of the power battery, 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 first phase winding, the second phase winding in the three-phase motor and the power battery are sequentially connected to form a charge-discharge circuit of the power battery, the three-phase motor is controlled to rotate to an angular position corresponding to the third phase of the three-phase motor.

6. The method of claim 1, wherein, The control of the on-off 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-discharge circuit of the power battery, comprises: The first switch module and the third switch module are controlled to be off, and the second switch module is controlled to be on; The first phase bridge arm in the inverter is controlled, so that the first phase bridge arm and two phase windings in the three-phase motor form a Boost circuit to realize discharging of the power battery; The first phase bridge arm in the inverter is controlled, so that the first phase bridge arm and two phase windings in the three-phase motor form a Buck circuit to realize charging of the power battery.

7. The method of claim 6, wherein, The control of 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, comprises: The first switch tube in the upper bridge arm of the first phase bridge arm in the inverter is controlled to be off, so that a diode connected in parallel with the first switch tube, 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 method of claim 6, wherein, The control of 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 Buck circuit, comprises: The first switch tube in the upper bridge arm of the first phase bridge arm in the inverter is controlled to be on, so that the first switch tube, the first phase winding connected with the first phase bridge arm and the second phase winding of the three-phase motor form a Buck circuit.

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