CN111355435B

CN111355435B - Motor control circuit, vehicle and heating method thereof

Info

Publication number: CN111355435B
Application number: CN201811575193.8A
Authority: CN
Inventors: 潘华; 谢飞跃; 洪臣; 黄丹丹; 刘益斌
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2018-12-21
Filing date: 2018-12-21
Publication date: 2022-04-15
Anticipated expiration: 2038-12-21
Also published as: CN111355435A

Abstract

The application provides a motor control circuit, a vehicle and a heating method thereof, wherein the motor control circuit comprises a voltage rising/reducing module, a three-phase inverter, a three-phase alternating current motor, a first switch module and a control module, N lines are led out from the connection points of three-line coils in the three-phase alternating current motor, and then forms different loops with the power battery, the voltage rising/reducing module and the three-phase inverter, when the control module obtains that the temperature of the device to be heated is lower than a preset temperature value, the control module controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor, therefore, the temperature of the to-be-heated device is increased, the temperature of the power battery can be increased without using an engine or adding a heating device, and the heating efficiency is high.

Description

Motor control circuit, vehicle and heating method thereof

Technical Field

The application relates to the technical field of motor control, in particular to a motor control circuit, a vehicle and a heating method of the motor control circuit.

Background

In recent years, new energy vehicles are developed vigorously, power batteries based on lithium ions are widely used, and due to the inherent characteristics of the batteries, the charge and discharge capacity of the power batteries is greatly reduced at low temperature, which affects the use of electric vehicles in cold regions.

In order to solve the problem, in the prior art, a technical scheme is that a battery management system acquires and sends the temperature of a power battery unit, if the temperature is lower than a preset temperature threshold value, a vehicle controller commands an engine controller to control an engine to rotate at a constant speed at a certain rotating speed through CAN communication, the engine drives a generator to rotate, and the power battery unit is rapidly charged and discharged through the generator to achieve the purpose of preheating a battery pack.

Another technical scheme in the prior art is that when the ambient temperature is low and the power battery needs to be heated, the cooling liquid is pumped out by the water pump from the refrigerating liquid tank and is sent into the liquid cooling plate of the power battery after being heated by the PTC heater, so that the temperature of the liquid cooling plate of the power battery is raised, and then the liquid cooling plate of the power battery heats the power battery, thereby improving the working performance of the power battery under the cold condition. In the technical scheme, a PTC heater is needed, so that the cost is increased, and if the PTC heater is damaged, the secondary cost is increased.

In summary, the prior art has problems that when the power battery is heated in a low temperature state, the battery heating efficiency is low due to the heating of the engine, and the cost is increased due to the heating of the PTC heater.

Disclosure of Invention

The application aims to provide a motor control circuit, a vehicle and a heating method thereof, and aims to solve the problems that when a power battery is heated in a low-temperature state, an engine is adopted to heat the power battery, so that the battery heating efficiency is low, and a PTC heater is adopted to heat the power battery, so that the cost is increased in the prior art.

The application is so realized, this application first aspect provides a motor control circuit, motor control circuit includes step-up/step-down module, three-phase inverter, first switch module and control module, three-phase alternating current motor three-phase inverter the step-up/step-down module and power module link to each other in proper order, power module passes through first switch module connects the tie point of three-phase coil among the three-phase alternating current motor, power module to step-up/step-down module with three-phase alternating current motor supplies power, power module still with step-up/step-down module and three-phase inverter connects altogether, control module connects respectively power module, treat the heating device step-up/step-down module three-phase alternating current motor and three-phase inverter.

A second aspect of the present application provides a heating method of a vehicle, based on the motor control circuit of the first aspect, the heating method including:

the control module controls the first switch module to be conducted when the temperature of the to-be-heated device is lower than a preset temperature value, and controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor, and then when the heated heat exchange medium flows through the to-be-heated device again, the temperature of the to-be-heated device is raised.

A third aspect of the present application provides a heating method of a vehicle, based on the motor control circuit of the first aspect, in which the power supply module includes an external power supply module and a second switch module that connects the external power supply module, the first switch module, the step-up/step-down module, and the three-phase inverter, the heating method including:

the control module obtains that the device to be heated needs to be heated, controls the first switch module and the second switch module to be conducted, controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor, and enables the temperature of the device to be heated to be increased when the heated heat exchange medium flows through the device to be heated again.

A fourth aspect of the present application provides a vehicle further comprising the motor control circuit of the vehicle of the first aspect.

The application provides a motor control circuit, a vehicle and a heating method thereof, wherein the motor control circuit comprises a voltage rising/reducing module, a three-phase inverter, a three-phase alternating current motor, a first switch module and a control module, the voltage rising/reducing module and a power supply module are sequentially connected, the power supply module is connected with a connection point of a three-phase coil in the three-phase alternating current motor through the first switch module, the power supply module supplies power to the voltage rising/reducing module and the three-phase alternating current motor, the power supply module is also connected with the voltage rising/reducing module and the three-phase inverter in a sharing way, the control module is respectively connected with the power supply module, a device to be heated, the voltage rising/reducing module, the three-phase alternating current motor and the three-phase inverter, and when the temperature of the device to be heated is lower than a preset temperature value, the control module controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to flow through the voltage rising/reducing module, And heating the heat exchange medium of at least one of the three-phase inverter and the three-phase alternating current motor. This application technical scheme draws forth neutral conductor in three-phase AC motor, and then constitutes different return circuits with power battery, step-up/step-down module and three-phase inverter, provide the heat source through inside three-phase coil of three-phase AC motor, three-phase inverter and step-up/step-down module and inside device that generates heat, the heating of treating the heating device is realized through former cooling circuit behind the heating heat transfer medium, need not use the engine or increase heating device just can realize promoting the temperature of treating the heating device, and heating efficiency is high.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a motor control circuit according to an embodiment of the present application;

FIG. 2 is a schematic diagram of another configuration of a motor control circuit according to an embodiment of the present application;

FIG. 3 is a circuit diagram of a motor control circuit provided in FIG. 2;

FIG. 4 is a schematic diagram of another configuration of a motor control circuit according to an embodiment of the present application;

FIG. 5 is a circuit diagram of a motor control circuit provided in FIG. 4;

FIG. 6 is a schematic diagram of another configuration of a motor control circuit according to another embodiment of the present application;

FIG. 7 is a schematic diagram of another configuration of a motor control circuit according to another embodiment of the present application;

FIG. 8 is a schematic diagram of another configuration of a motor control circuit according to another embodiment of the present application;

FIG. 9 is a schematic diagram of another configuration of a motor control circuit according to another embodiment of the present application;

FIG. 10 is a current path diagram of a motor control circuit provided in FIG. 3;

FIG. 11 is another current path diagram of a motor control circuit provided in FIG. 3;

FIG. 12 is a current diagram of a motor control circuit provided in FIG. 9;

FIG. 13 is a current path diagram of a motor control circuit provided in FIG. 3;

FIG. 14 is another current path diagram of a motor control circuit provided in FIG. 3;

FIG. 15 is a schematic illustration of a vehicle according to another embodiment of the present application;

fig. 16 is a schematic internal structural diagram of a three-phase ac motor in a vehicle according to another embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In order to explain the technical means of the present application, the following description will be given by way of specific examples.

The embodiment of the application provides a motor control circuit, as shown in fig. 1, the motor control circuit includes a voltage rising/reducing module 102, a three-phase inverter 103, a first switch module 105 and a control module 106, a three-phase ac motor 104, the three-phase inverter 103, the voltage rising/reducing module 102 and a power supply module 101 are sequentially connected, the power supply module 101 is connected to a connection point of a three-phase coil in the three-phase ac motor 104 through the first switch module 105, the power supply module 101 supplies power to the voltage rising/reducing module 102 and the three-phase ac motor 104, the power supply module 101 is further connected to the voltage rising/reducing module 102 and the three-phase inverter 103 in a common manner, and the control module 106 is respectively connected to the power supply module 101, a device to be heated, the voltage rising/reducing module 102, the three-phase ac motor 104 and the three-phase inverter 103.

The power supply module 101 may be a power supply module inside the vehicle or a power supply module outside the vehicle, for example, the power supply provided by the power supply module 101 may be direct current provided by a direct current charging pile, direct current output by a single-phase or three-phase alternating current charging pile after rectification, electric energy generated by a fuel cell, a power supply form such as a power supply form in which a range extender such as an engine rotates to drive a generator to generate electricity, direct current rectified by a generator controller, and the like, or an electric pipe provided by a power battery inside the vehicle; the step-up/step-down module 102 is configured to store electric energy when being connected to a loop of the power supply module 101, and release current to pump up voltage in a loop that is not connected to the power supply module 101, the step-up/step-down module 102 may include an energy storage unit and a power switch unit, and may be respectively connected to a positive electrode and a negative electrode of the power battery 110 through the energy storage unit and the power switch, a control end of the power switch unit is connected to the control module 106, and the power switch unit in the step-up/step-down module 102 is turned on or off according to a signal output by the control module 106, so that the energy storage unit is connected to different loops to be charged or discharged; the three-phase inverter 103 comprises six power switch units, the power switches can be of transistor, IGBT, MOS tube and other device types, two power switch units form a phase bridge arm, the two phase bridge arms form a three-phase bridge arm, the connection point of the two power switch units in each phase bridge arm is connected with a phase coil in the three-phase alternating current motor 104, the three-phase alternating current motor 104 comprises a three-phase coil, the three-phase coil is connected with a middle point, the three-phase alternating current motor 104 can be a permanent magnet synchronous motor or an asynchronous motor, the three-phase alternating current motor 104 is of a three-phase four-wire system, namely, N wires are led out from the connection point of the three-phase coil, and the N wires and the first switch module 105 are connected in series to form a connection circuit; the first switch module 105 is used for cutting off the connection point of the three-phase coil in the three-phase alternating current motor 104 and the connection of the power supply module 101 through the first switch module 105 when charging is not needed, such as when a vehicle runs normally, and cutting off a charging loop when other abnormality and failure occur in the charging process; the control module 106 CAN acquire the voltage, the current, the temperature of the power supply module 101 and the phase current of the three-phase alternating current motor 104, the control module 106 CAN include a vehicle controller, a control circuit of the motor controller and a BMS battery manager circuit, which are connected by CAN lines, different modules in the control module 106 control the on and off of power switches in the step-up/step-down module 102 and the three-phase inverter 103 according to the acquired information to realize the on of different current loops, the device to be heated CAN be any one component in the vehicle, the device to be heated is connected with the control module, when the control module acquires that the temperature of the device to be heated is lower than a preset temperature, the control module controls the on of the first switch module to enable the step-up/step-down module 102, the three-phase inverter 103 and the three-phase alternating current motor 104 to be in a working state to generate heat to heat the device to be heated, the device to be heated may be located near the step-up/down module 102, the three-phase inverter 103, and the three-phase ac motor 104, for example, the device to be heated and at least one of the step-up/down module 102, the three-phase inverter 103, and the three-phase ac motor 104 are located in the same compartment, or heat of at least one of the step-up/down module 102, the three-phase inverter 103, and the three-phase ac motor 104 may be transferred to the device to be heated by a heat exchange medium, for example, a heat exchange medium line is provided on the power battery, the step-up/down module 102, the three-phase inverter 103, and the three-phase ac motor 104, a heat exchange medium flows in the heat exchange medium line, and temperature adjustment may be performed on the heat exchange medium of the heat exchange medium line to adjust the temperature of the device to be heated.

In the embodiment, the N lines are led out from the connection point of the three-line coil of the three-phase alternating current motor, and then form different loops with the first switch module, the voltage rising/reducing module and the three-phase inverter, a heat source is provided through the three-phase coil inside the three-phase alternating current motor, the three-phase inverter, the voltage rising/reducing module and an internal heating device thereof, the temperature of the power battery can be increased without using an engine or adding a heating device, the heating efficiency is high, and the temperature of the power battery is quickly increased.

As a connection manner of this embodiment, a first end of the step-up/down module 102 is connected to a positive end of the power supply module 101 and a first end of the first switch module 105, a second end of the first switch module 105 is connected to a connection point of three-phase coils in the three-phase ac motor 104, the three-phase coils of the three-phase ac motor 104 are respectively connected to midpoints of three-phase arms of the three-phase inverter 103, the first end of the three-phase inverter 103 is connected to a second end of the step-up/down module 102, and the second end of the three-phase inverter 103 is connected to a third end of the step-up/down module 102 and a negative end of the power supply module 101.

Further, as shown in fig. 2, the step-up/down module 102 includes an energy storage unit 111, a seventh power switch unit 112, and an eighth power switch 113, where a first end of the energy storage unit 111 is a first end of the step-up/down module 102, a second end of the energy storage unit 111 is connected to a second end of the seventh power switch unit 112 and a first end of the eighth power switch 113, the first end of the seventh power switch unit 112 is a second end of the step-up/down module 102, and a second end of the eighth power switch unit 113 is a third end of the step-up/down module 102.

The energy storage unit 111 may be an energy storage device such as an inductor, the seventh power switch unit 112 and the eighth power switch unit 113 may be a transistor, an IGBT, an MOS transistor, or another device type, two power switch units form a phase bridge arm, and the seventh power switch unit 112 and the eighth power switch unit 113 may be controlled to be alternately turned on by outputting a PWM control signal to the seventh power switch unit 112 and the eighth power switch unit 113.

For the three-phase inverter 103, specifically, the three-phase inverter 103 includes a first power switch unit, a second power switch unit, a third power switch unit, a fourth power switch unit, a fifth power switch unit, and a sixth power switch, a control end of each power switch unit is connected to the control module 106, input ends of the first power switch unit, the third power switch unit, and the fifth power switch unit are connected in common and form a first end of the three-phase inverter 103, output ends of the second power switch unit, the fourth power switch unit, and the sixth power switch unit are connected in common and form a second end of the three-phase inverter 103, a first phase coil of the three-phase ac motor 104 is connected to an output end of the first power switch unit and an input end of the fourth power switch unit, a second phase coil of the three-phase ac motor 104 is connected to an output end of the third power switch unit and an input end of the sixth power switch unit, the third phase coil of the three-phase ac motor 104 is connected to the output terminal of the fifth power switching unit and the input terminal of the second power switching unit.

The first power switch unit and the fourth power switch unit in the three-phase inverter 103 form an a-phase bridge arm, the third power switch unit and the sixth power switch unit form a B-phase bridge arm, the input end of the fifth power switch unit and the second power switch unit form a C-phase bridge arm, and the control mode of the three-phase inverter 103 may be any one of the following or a combination of several of the following: if any one or any two of A, B, C three-phase bridge arms and three bridge arms can be realized, 7 control heating modes are realized, and the method is flexible and simple. The switching of the bridge arms can be beneficial to realizing the large, medium and small selection of heating power, for example, for small-power heating, any phase of bridge arm power switches can be selected for control, and three-phase bridge arms can be switched in turn, for example, an A-phase bridge arm works alone first, a first power switch unit and a fourth power switch unit are controlled to heat for a period of time, then a B-phase bridge arm works alone, a third power switch unit and a sixth power switch unit are controlled to heat for the same period of time, then a C-phase bridge arm works alone, a fifth power switch unit and a second power switch unit are controlled to heat for the same period of time, and then the A-phase bridge arm works, so that the three-phase inverter 103 and a three-phase coil are circulated to be electrified and heated in turn, and three-phase heating is more balanced; for medium-power heating, any two-phase bridge arm power switches can be selected for control, and three-phase bridge arms can be switched in turn, for example, an AB-phase bridge arm works first, a first power switch unit, a fourth power switch unit, a third power switch unit and a sixth power switch unit are controlled to heat for a period of time, then a BC-phase bridge arm works, a third power switch unit, a sixth power switch unit, a fifth power switch unit and a second power switch unit are controlled to heat for the same time, then a CA-phase bridge arm works, a fifth power switch unit, a second power switch unit, a first power switch unit and a fourth power switch unit are controlled to heat for the same time, and then the CA-phase bridge arm works, and the steps are repeated to realize that the three-phase inverter 103 and a three-phase coil heat more evenly; for high-power heating, a three-phase bridge arm power switch can be selected to control, three-phase currents are balanced due to the fact that a three-phase loop is balanced theoretically, the three-phase currents are basically direct currents and are balanced by the three-phase inverter 103 and a three-phase coil, average values of the three-phase currents are basically consistent, three-phase synthetic magnetomotive force in the motor is basically zero due to the fact that three-phase windings are symmetrical, a stator magnetic field is basically zero, the motor basically does not generate torque, and stress of a transmission system is greatly reduced.

The technical scheme of the present application is specifically described below by a specific circuit structure:

fig. 3 is an exemplary circuit diagram of a control circuit of a power motor of the present application, in order to facilitate explanation of the control circuit of the motor, other electrical devices are omitted from the upper diagram, only a power battery, a step-up/step-down module, a three-phase inverter and a three-phase ac motor are considered, the step-up/step-down module 102 includes an energy storage unit, a seventh power switching unit and an eighth power switching unit, the energy storage unit is an inductor L, the seventh power switching unit includes a seventh upper bridge arm VT7 and a seventh upper bridge diode VD7, the eighth power switching unit includes an eighth lower bridge VT8 and an eighth lower bridge diode VD8, a first power switching unit in the three-phase inverter 103 includes a first upper bridge arm VT1 and a first upper bridge diode VD1, the second power switching unit includes a second lower bridge arm VT2 and a second lower bridge diode VD2, the third power switching unit includes a third upper bridge arm VT3 and a third upper bridge diode VD3, the fourth power switch unit comprises a fourth lower bridge arm VT4 and a fourth lower bridge diode VD4, the fifth power switch unit comprises a fifth upper bridge arm VT5 and a fifth upper bridge diode VD2, the sixth power switch unit comprises a sixth lower bridge arm VT6 and a sixth lower bridge diode VD6, the three-phase alternating-current motor 104 is a three-phase four-wire system, N wires are led out from connection points of three-phase coils, the N wires and the switch K1 are connected in series to form a connecting circuit, and the three-phase coils of the motor are respectively connected with the upper and lower bridge arms A, B, C in the three-phase inverter.

As another connection mode of the present embodiment, as shown in fig. 4, a first end of the voltage rising/decreasing module 102 is connected to a positive end of the power supply module 101 and a first end of the first switch module 105, a second end of the first switch module 105 is connected to a connection point of three-phase coils in the three-phase ac motor 104, the three-phase coils of the three-phase ac motor 104 are respectively connected to a midpoint of a three-phase arm of the three-phase inverter 103, the first end of the three-phase inverter 103 is connected to a second end of the voltage rising/decreasing module 102, and the second end of the three-phase inverter 103 is connected to a negative end of the power supply module 101.

Further, the step-up/down module 102 includes an energy storage unit 111 and a seventh power switch unit 112, a first end of the energy storage unit 111 is a first end of the step-up/down module 102, a second end of the energy storage unit 111 is connected to a second end of the seventh power switch unit 112, a first end of the seventh power switch unit 112 is a second end of the step-up/down module 102, and the control module 106 is connected to a control end of the seventh power switch unit 112.

Fig. 5 is a circuit diagram of another example of the motor control circuit of the present application, which is different from fig. 3 in that: the voltage rising/reducing module only comprises an energy storage unit and a seventh power switch unit.

As for the power supply module, as an embodiment of the power supply module, the device to be heated and the power supply module are the same component, such as a power battery. Like this, not only at the in-process that forms the circuit loop, power battery can make self temperature rise because of the internal resistance, and, can also be through the produced heat transfer of the motor control circuit in this application for power battery, promptly: the motor control circuit in this application both can be used for charging power battery, also can be used for power battery to supply power for three-phase alternating current motor in order to drive the wheel rotation, can also be used to provide the heat source for the power battery that needs the heating.

As an embodiment of the power supply module, the power supply module is an external power supply module, and the device to be heated is a power battery.

The second embodiment of the present application provides a heating method for a vehicle, and based on the motor control circuit provided in the first embodiment, the heating method includes:

the control module obtains that the device to be heated needs to control the first switch module to be conducted when heating, and controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor.

When the device to be heated is a power battery, due to the inherent characteristics of the power battery, the charging and discharging capacity of the power battery is greatly reduced in a low-temperature state, the use of a new energy automobile in a cold region is influenced, in order to enable the power battery to work normally, the temperature of the power battery needs to be raised when the temperature of the power battery is too low, therefore, the temperature of the power battery is obtained through the control module, the temperature of the power battery can be obtained through the battery manager, the temperature of the power battery is compared with a preset temperature value to judge whether the power battery is in the low-temperature state, when the obtained temperature of the power battery is lower than the preset temperature value, the temperature of the power battery can be raised in a mode of raising the temperature of a heat exchange medium flowing through the power battery, and as the voltage raising/lowering module, the three-phase inverter and the three-phase alternating current motor all generate heat in the working process, therefore, the step-up/down module, the three-phase inverter and the three-phase alternating current motor can be controlled to heat the heat exchange medium flowing through the power battery, the temperature of the power battery is raised when the heated heat exchange medium flows through the power battery again, the step-up/down module, the three-phase inverter and the three-phase alternating current motor can work all the time or part of equipment in the step-up/down module, the three-phase inverter and the three-phase alternating current motor can work alternately, and heating is stopped when the obtained temperature of the power battery reaches the preset temperature value.

As one embodiment, the power supply module is a power battery; the device to be heated comprises a power battery; when the power battery can realize discharging, the following modes can be adopted to control the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat the cooling liquid flowing through the power battery: as shown in fig. 6, the power battery 110, the first switching module 105, the three-phase ac motor 104, and the three-phase inverter 103 form a first current loop, and the buck/boost module 102, the three-phase ac motor 104, and the three-phase inverter 103 form a second current loop.

The heating method comprises the following steps: controlling the step-up/down module, the three-phase inverter and the three-phase alternating current motor to heat a heat transfer medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor, including:

and controlling the step-up/down module and the three-phase inverter to enable the first current loop and the second current loop to be conducted alternately, wherein the step-up/down module, the three-phase inverter and the three-phase alternating current motor generate heat to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor.

As shown in fig. 6, the control module 106 controls the connection and disconnection of the step-up/down module 102 and the power switch unit in the three-phase inverter 103 to control the first current loop and the second current loop to be alternately connected, when the control module 106 controls the first current loop to be connected, the current output by the power battery 110 flows through the first switch module 105, the three-phase ac motor 104 and the three-phase inverter 103, and then returns to the power battery 110, at this time, the first current loop forms an inductive energy storage loop, and the three-phase ac motor 104 and the three-phase inverter 103 start to work as a heat exchange medium to heat; when the control module 106 controls the second current loop to be conducted, the voltage rising/reducing module 102 and the three-phase alternating current motor 104 both output current, so that the second current loop forms a current follow current loop, and the heating of the heat exchange medium flowing through the power battery 110 by the voltage rising/reducing module 102, the three-phase inverter 103 and the three-phase alternating current motor 104 is realized.

In the embodiment, a neutral line is led out of the three-phase alternating current motor, so that different loops are formed with the power battery, the voltage rising/reducing module and the three-phase inverter, a heat source is provided through the three-phase coil inside the three-phase alternating current motor, the three-phase inverter, the voltage rising/reducing module and an internal heating device thereof, the power battery is heated through the original cooling loop after the heat exchange medium is heated, the temperature of the power battery can be increased without using an engine or adding a heating device, the heating efficiency is high, and the temperature of the power battery is quickly increased.

Further, as shown in fig. 5 and 7, the step-up/down module includes an energy storage unit 111 and a seventh power switch unit 112, when the control module 106 controls the step-up/down module 102 and the three-phase inverter 103 to make the first current loop conduct and make the second current loop close, the control module 106 controls the seventh power switch unit to turn off, and controls at least one functional switch unit among the second power switch unit, the fourth power switch unit and the sixth power switch unit to turn on, so that the current output by the power battery 110 flows through the first current loop;

when the control module 106 controls the step-up/down module 102 and the three-phase inverter 103 to turn off the first current loop and turn on the second current loop, the control module 106 controls the seventh power switch unit to turn on, and controls at least one functional switch unit among the first power switch unit, the third power switch unit, and the fifth power switch unit to turn on, so that the currents of the three-phase ac motor 104 and the step-up/down module 102 flow through the second current loop.

Further, as shown in fig. 8, the up/down voltage module 102 and the power battery 110 form a third current loop, and the second current loop and the third current loop form a first current loop group;

controlling the step-up/down module, the three-phase inverter and the three-phase alternating current motor to heat a heat transfer medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor, including:

and controlling the step-up/down module and the three-phase inverter to enable the first current loop and the first current loop group to be conducted alternately, so that the step-up/down module, the three-phase inverter and the three-phase alternating current motor generate heat to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor.

As shown in fig. 8, the voltage step-up/down module 102 includes an energy storage unit 111, a seventh power switch unit 112, and an eighth power switch unit 113, and the power battery 110, the energy storage unit 111, and the eighth power switch unit 113 form a third current loop;

when the control module 106 controls the step-up/down module 102 and the three-phase inverter 103 to turn on the first current loop and turn off the second current loop, the control module 106 controls the seventh power switch unit to be turned off, and controls at least one functional switch unit among the second power switch unit, the fourth power switch unit and the sixth power switch unit to be turned on, so that the current output by the power battery 110 flows through the first current loop;

when the control module 106 controls the step-up/down module 102 and the three-phase inverter 103 to turn off the first current loop and turn on the second current loop, the control module 106 controls the seventh power switch unit to be turned on, and controls at least one functional switch unit among the first power switch unit, the third power switch unit, and the fifth power switch unit to be turned on, so that the currents of the three-phase ac motor 104 and the step-up/down module 102 flow through the second current loop, and the control module 106 controls the eighth power switch unit to be turned on, so that the current of the step-up/down module 102 flows through the third current loop.

The present embodiment is different from the above-described embodiments in that: in addition, because the energy storage unit has current, when the control module controls the conduction of the second current loop, the power battery, the energy storage unit and the eighth power switch unit form an independent follow current loop, so that the eighth power switch unit in the voltage rising/reducing module also generates heat, the temperature rising efficiency of the power battery is improved, and the voltage output by the external power module can be boosted through energy storage.

As an embodiment, controlling the buck/boost module and the three-phase inverter to alternately conduct the first current loop and the second current loop includes:

and outputting PWM control signals to the voltage rising/reducing module and the three-phase inverter to enable the first current loop and the second current loop to be alternately conducted, acquiring the actual charging current of the power battery, comparing the actual charging current with the target charging current corresponding to the preset heating power, and adjusting the duty ratio of the PWM control signals according to the comparison result to adjust the actual charging current to the target charging current.

The control module receives power to be charged sent by the battery manager, acquires the power to be charged and acquires corresponding current, compares the charging current for charging the power battery with the current acquired by the power to be charged, adjusts and increases the PWM conduction duty ratio when the charging current is smaller than the current value corresponding to the required charging power, and adjusts and decreases the PWM conduction duty ratio when the charging current is larger than the current value corresponding to the required charging power until the charging power is met.

Further, as an embodiment, the control module needs to determine whether the received information meets a preset condition before controlling the step-up/step-down module, the three-phase inverter and the three-phase ac motor to heat the cooling liquid flowing through the power battery, where the preset condition may include other determination conditions besides the determination of the temperature value of the power battery.

The control module obtains and controls first switch module when treating the temperature of heating the device and be less than preset temperature value and switch on, still includes:

the control module acquires a state signal (such as the state signal can be determined by gear information and a vehicle speed signal) of the three-phase alternating current motor and temperature information of the power battery;

when the three-phase alternating current motor is judged to be in a non-driving state (such as determined by whether a gear is in a P gear and the vehicle speed is zero) and the temperature of the power battery is lower than a preset temperature value, controlling the first switch module to be conducted;

when the three-phase alternating current motor is judged to be in a non-driving state and the temperature of the power battery is not lower than a preset temperature value, gear information, vehicle speed information and temperature information of the power battery are obtained again;

controlling the step-up/down module, the three-phase inverter and the three-phase alternating current motor to generate heat to heat a heat transfer medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor, and then further comprising:

and when the three-phase alternating current motor is in a driving state or the temperature of the power battery is not lower than a preset temperature value, controlling the first switch module to be switched off.

As shown in fig. 6, when the non-driving state is that the current gear is the P gear or the vehicle speed is 0, that is, the temperature of the power battery obtained when the vehicle is in the parking state is low, the control module 106 controls the step-up/step-down module 102, the three-phase inverter 103 and the three-phase ac motor 104 to heat the heat transfer medium flowing through the power battery 110, and when one of the current gear, the vehicle speed and the temperature of the power battery 110 obtained in a circulating manner during the heating process does not meet a preset condition, the heating is stopped, and all the switch modules are controlled to be turned off.

In the embodiment, when the gear information, the vehicle speed information and the temperature information of the power battery which are acquired in the parking state meet the preset conditions, the power battery is controlled to output current, and the coolant flowing through the power battery is heated through the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor, so that the power battery is heated in the parking state of the electric vehicle, and the electric vehicle can be normally started in the low-temperature condition.

In another embodiment of the present invention, based on the motor control circuit provided in the first embodiment, as shown in fig. 9, when the power battery 110 cannot discharge, for example, at an extremely low temperature or when the power battery 110 has a low electric quantity, the step-up/step-down module 102, the three-phase inverter 103, and the three-phase ac motor 104 may be controlled to heat the coolant flowing through the power battery 110 in the following manner:

the power supply module 101 further comprises an external power supply module 108 and a second switch module 107, the external power supply module 108 is connected in series with the second switch module 107 and then connected in parallel with the power battery 110, and a control end of the second switch module 107 is connected with the control module 106; the heating method comprises the following steps:

the control module obtains that the device to be heated needs to control the first switch module and the second switch module to be conducted when heating, and controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor, and then when the heated heat exchange medium flows through the device to be heated again, the temperature of the device to be heated is increased.

The external power supply module 108, the second switching module 107, the first switching module 105, the three-phase ac motor 104, and the three-phase inverter 103 form a fourth current loop, and the step-up/step-down module 102, the three-phase ac motor 104, and the three-phase inverter 103 form a second current loop.

the control module is used for acquiring that the temperature of the power battery is lower than a preset temperature value, controlling the first switch module and the second switch module to be conducted when the electric quantity of the power battery is lower than a preset electric quantity value or the external temperature is lower than a preset temperature value, and controlling the voltage rising/reducing module and the three-phase inverter to enable the fourth current loop and the second current loop to be conducted alternately, so that the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor heat cooling liquid flowing through the power battery.

Wherein, the external power supply module 108 may be a direct current provided by the direct current charging pile, or a direct current output by a single-phase or three-phase alternating current charging pile after rectification, or an electric energy generated by a fuel cell, or a power form such as a range extender such as an engine rotating to drive a generator to generate electricity, or a direct current rectified by a generator controller, the control module 106 controls the second switch module 107 to be turned on, so that the external power supply module 108 outputs a current, and controls the on/off of the power switch units in the step-up/step-down module 102 and the three-phase inverter 103 to control the first current loop and the second current loop to be alternately turned on, when the control module 106 controls the first current loop to be turned on, the current output by the external power supply module 108 flows through the second switch module 107, the first switch module 105, the three-phase alternating current motor 104 and the three-phase inverter 103, and then returns to the external power supply module 108, at the moment, the first current loop forms an inductive energy storage loop, and the three-phase alternating current motor 104 and the three-phase inverter 103 start to work to heat the cooling liquid; when the control module 106 controls the second current loop to be conducted, the voltage rising/reducing module 102 and the three-phase alternating current motor 104 both output current, so that the second current loop forms a current follow current loop, and the heating of the cooling liquid flowing through the power battery 110 by the voltage rising/reducing module 102, the three-phase inverter 103 and the three-phase alternating current motor 104 is realized.

In the embodiment, a neutral line is led out of the three-phase alternating current motor, and then the neutral line and the external power supply module, the voltage rising/reducing module and the three-phase inverter form different loops, a heat source is provided through the three-phase coil inside the three-phase alternating current motor, the three-phase inverter, the voltage rising/reducing module and an internal heating device thereof, heating of the power battery is realized through the original cooling loop after the cooling liquid is heated, the temperature of the power battery can be increased without using an engine or adding a heating device, the heating efficiency is high, and the temperature of the power battery is quickly increased.

Further, as an embodiment, before controlling the step-up/down module 102, the three-phase inverter 103, and the three-phase ac motor 104 to heat the cooling liquid flowing through the power battery 110, the control module 106 needs to determine whether the received information meets a preset condition, where the preset condition may include, in addition to the determination of the temperature value of the power battery 110, other determination conditions:

acquiring a state signal (such as a state signal which can be determined by gear information and a vehicle speed signal) of a three-phase alternating current motor and temperature information of a power battery;

when the state signal of the three-phase alternating current motor is judged to be in a non-driving state (such as determined by whether a gear is in a P gear and the vehicle speed is zero) and the temperature of the power battery is lower than a preset temperature value, controlling the first switch module and the second switch module to be conducted;

make step-up/step-down module, three-phase inverter and three-phase alternating current motor heat the coolant liquid that flows through power battery, later still include:

and when the three-phase alternating current motor is in a driving state or the temperature of the power battery is not lower than a preset temperature value, controlling the first switch module and the second switch module to be switched off.

The preset condition is a non-driving state, that is, when the current gear is the P gear, the vehicle speed is 0, and the temperature of the power battery 110 does not reach a preset temperature value, that is, when the temperature of the power battery 110 obtained in the parking state of the vehicle is low, and the power battery 110 cannot output current due to low electric quantity or low external temperature, the current can be output through the external power supply module, after the control module 106 switches on the first switch module 105 and the second switch module, the control module 106 controls the step-up/step-down module 102, the three-phase inverter 103 and the three-phase alternating current motor 104 to heat the coolant flowing through the power battery 110, and when one of the current gear, the vehicle speed and the temperature of the power battery 110 which are obtained in a circulating manner in the heating process does not meet the preset condition, the heating is stopped, and all the switch modules are controlled to be switched off.

In the embodiment, when the state signal of the three-phase alternating current motor and the temperature information of the power battery meet the preset conditions in the parking state, the power battery can not output current, the current is output through the external power supply module, and the heat exchange medium flowing through the power battery is heated through the voltage increasing/decreasing module, the three-phase inverter and the three-phase alternating current motor, so that the power battery can be heated in the parking state of the electric vehicle, and the electric vehicle can be normally started in the low-temperature condition.

As an embodiment, the alternating conduction of the first current loop and the second current loop may be controlled in the following manner: the control module 106 outputs PWM control signals to the step-up/step-down module 102 and the three-phase inverter 103 to alternately turn on the first current loop and the second current loop, obtains an actual charging current of the power battery 110, compares the output power with a target charging current corresponding to a preset heating power, and adjusts a duty ratio of the PWM control signal according to a comparison result to adjust the output power to the preset heating power.

The control module 106 receives the power to be charged sent by the battery manager, acquires the power to be charged, acquires a corresponding target charging current, compares an actual charging current for charging the power battery 110 with the target charging current corresponding to the power to be charged, adjusts and increases the PWM on-duty ratio when the actual charging current is smaller than the target charging current, and adjusts and decreases the PWM on-duty ratio when the actual charging current is larger than the target charging current until the charging power is satisfied.

The technical scheme of the present application is explained by a specific circuit structure as follows:

fig. 3 is a circuit diagram illustrating an example of a power battery heating apparatus according to the present application, in an embodiment, when it is required to heat the power battery 110, in order to heat the power battery 110, the control steps of the control module specifically include:

step 1, when the whole vehicle is powered on, the whole vehicle controller receives a state signal of the three-phase alternating current motor and a temperature signal of the power battery 110 sent by the battery manager.

And 2, the vehicle control unit acquires whether the current gear is in the P gear and the vehicle speed is zero according to the state signal of the three-phase alternating current motor.

And 3, if not, exiting the motor heating program.

And 4, if so, judging whether the temperature of the power battery is lower than a set threshold value.

And 5, if not, exiting the motor heating program.

And 6, if so, the vehicle control unit sends a battery heating instruction and heating power to the battery manager and the motor controller.

Step 7, as shown in fig. 10, the battery manager controls the switch K1 to be turned on, the motor controller controls the seventh upper arm VT7 in the step-up/step-down module 102 to keep an on state, the eighth lower arm VT8 in the step-up/step-down module 102 to keep an off state, the motor controller controls the lower bridge power switch of the three-phase inverter 103 to be turned on during the PWM cycle, the upper bridge power switch is turned off, the power battery 110 discharges, the current reaches the three-phase coil of the motor through the positive electrode of the power battery 110, the switch K1 and the neutral line, and then reaches the negative electrode of the battery through the lower three power switches (the second upper arm VT2, the fourth upper arm VT4 and the sixth upper arm VT6) of the three-phase inverter 103, so as to form an inductive energy storage loop.

Step 8, as shown in fig. 11, the seventh upper leg VT7 and the eighth lower leg VT8 in the step-up/step-down module 102 keep on and off, the motor controller controls the lower power switches (the second upper leg VT2, the fourth upper leg VT4, and the sixth upper leg VT6) of the three-phase inverter 103 to turn off during the PWM cycle, the upper power switches (the first upper leg VT1, the third upper leg VT3, and the fifth upper leg VT5) can be turned off or turned on all the time, at this time, the discharging path of the power battery 110 is cut off, the current of the three-phase coil forms a follow current through the upper bridge diodes (the first upper bridge diode VD1, the third upper bridge diode VD3 and the fifth upper bridge diode VD5), and the current returns to the three-phase coil of the motor through the three-phase coil, the upper bridge diode of the three-phase inverter 103, the seventh upper bridge arm VT of the step-up/step-down module 102, the inductor L and the neutral wire to form an inductive current follow current loop.

In addition, because current exists in the inductor L, when the motor controller controls the power switch of the lower bridge of the three-phase inverter 103 to be turned on, an independent freewheeling loop is formed, the inductor L is connected to the positive electrode of the battery, and the negative electrode of the battery is connected to the other end of the inductor L through the eighth lower bridge diode VD8 in the step-up/step-down module 102.

And 9, receiving voltage and current data of the power battery 110 by the motor controller, calculating output power, regarding the output power as battery heating power, comparing the calculated battery heating power with heating command power sent by the battery manager, increasing the PWM duty ratio and increasing the battery output current if the calculated heating power is low, and decreasing the PWM duty ratio and the battery output current if the calculated heating power is high until the heating power reaches the vicinity of the heating command power.

And step 10, circularly acquiring the gear, the vehicle speed and the temperature of the power battery 110 by the vehicle controller, repeating the steps 2-9 when the conditions are met, and exiting the heating program when the conditions are not met.

And step 11, if the heating condition is not met, the heating program is quitted, the motor controller controls the voltage rising/reducing module 102 and the three-phase inverter 103 to be completely switched off from the upper bridge to the lower bridge, and the battery manager controls the switch K1 to be switched off.

Fig. 12 is a schematic structural diagram of another example of the power battery heating apparatus according to the present application, when the temperature is extremely low, or the battery capacity is extremely low, and the power battery 110 cannot be heated by the self-discharge of the battery, an external power supply module is required to heat the battery, and in order to heat the battery, the control steps of the control module 106 specifically include:

And 3, if not, exiting the motor heating program.

And 4, if so, judging whether the temperature of the power battery 110 is lower than a set threshold value.

And 5, if not, exiting the motor heating program.

Step 6, if the temperature is extremely low or the battery electric quantity is extremely low, the vehicle control unit sends a battery heating instruction and heating power to the battery manager and the motor controller;

step 7, as shown in fig. 13, the battery manager controls the switches K1, K2, and K3 to be turned on, the motor controller controls the seventh upper arm VT7 in the step-up/step-down module 102 to keep an on state, the eighth lower arm VT8 keeps an off state, the motor controller controls the lower bridge power switch of the three-phase inverter 103 to be turned on during the PWM cycle, the upper bridge power switch is turned off, the charging pile 108 is discharged, the current reaches the three-phase coil of the motor through the switch K2, the switch K1, and the neutral line, and then passes through the three power switches (the second lower arm VT2, the fourth lower arm VT4, the sixth lower arm VT6), the switch K3 in the lower bridge of the three-phase inverter 103 and then reaches the charging pile, so as to form an inductance energy storage loop.

Step 8, as shown in fig. 14, the seventh upper leg VT7 and the eighth lower leg VT8 in the step-up/step-down module 102 keep on and off, the motor controller controls the lower leg power switches (the second lower leg VT2, the fourth lower leg VT4, and the sixth lower leg VT6) of the three-phase inverter 103 to turn off during the PWM cycle, the upper leg power switches (the first upper leg VT1, the third upper leg VT3, and the fifth upper leg VT5) can be turned off or turned on all the time, at this time, the discharging path of the power battery 110 is cut off, the current of the three-phase coil forms a follow current through the upper bridge diodes (the first upper bridge diode VD1, the third upper bridge diode VD3 and the fifth upper bridge diode VD5), and the current returns to the three-phase coil of the motor through the three-phase coil, the upper bridge diode of the three-phase inverter 103, the seventh upper bridge arm VT of the step-up/step-down module 102, the inductor L and the neutral wire to form an inductive current follow current loop.

And step 11, if the heating condition is not met, exiting the heating program, controlling the upper and lower bridges of the step-up/step-down module 102 and the three-phase inverter 103 to be completely switched off by the motor controller, and controlling the switch K1, the switch K2 and the switch K3 to be switched off by the battery manager.

Another embodiment of the application provides a vehicle, which further comprises the motor control circuit provided by the first embodiment, and the vehicle further comprises a driving module and a heat exchange medium pipeline, wherein the driving module is connected with the control module; the control module controls the driving module to drive the heat exchange medium in the heat exchange medium pipeline to flow through at least one of the energy storage module, the three-phase inverter and the three-phase alternating current motor.

As shown in fig. 15, the control module includes a vehicle control unit 301, a battery manager 302, a first motor controller 305, and a second motor controller 303, the vehicle control unit 301 is connected to the battery manager 302, the first motor controller 305, and the second motor controller 303 through a CAN bus, a dc charging post is electrically connected to a first three-phase ac motor 306 through a connection line 307, the dc charging post is electrically connected to a second three-phase ac motor 304 through a connection line 310, a power battery is electrically connected to the first motor controller 305 and the second motor controller 303, a cooling liquid tank 308, a water pump 309, the first three-phase ac motor 306, the first motor controller 305, the second three-phase ac motor 304, the second motor controller, and the power battery form a cooling liquid pipeline, the battery manager 302 is configured to collect power battery information including voltage, current, temperature, and the like, the motor controller is used for controlling power switches of an upper bridge and a lower bridge of the three-phase inverter and collecting three-phase current, and the vehicle controller is used for managing the operation of a whole vehicle and other controller equipment on the vehicle. The battery manager 302 and the motor controller are communicated with the vehicle control unit 301 through a CAN (controller area network) line, when the vehicle control unit 301 obtains that the power battery needs to be heated, the water pump 309 is controlled to pump cooling liquid out of the cooling liquid tank 308, a cooling liquid water pipeline sequentially passes through the first three-phase alternating current motor 306, the first motor controller 305, the second three-phase alternating current motor 304 and the second motor controller 303 to flow through the power battery, the vehicle control unit 301 controls the first three-phase alternating current motor 306, the first motor controller 305, the second three-phase alternating current motor 304 and the second motor controller 303 to work so as to heat the cooling liquid, and then when the cooling liquid flows through the power battery, the temperature of the power battery is increased.

Further, as shown in fig. 16, the three-phase ac motor 102 includes a motor shaft 125a, a stator assembly 127a, and a motor housing 123a, the motor shaft 125a is connected to the stator assembly 127a and the bearing seat 124a, the stator assembly 127a is disposed in the motor housing 123a, the motor housing 123a is provided with a heat exchange medium inlet 121a and a heat exchange medium outlet 126a through which the heat exchange medium 122a flows in and out, a heat exchange medium channel is disposed between the motor housing 123a and the stator assembly 127a, and the heat exchange medium channel is connected to the heat exchange medium inlet 121a and the heat exchange medium outlet 126 a.

The heat exchange medium channel may be provided between the motor housing 123a and the stator assembly 127a, and the heat exchange medium channel spirally surrounding the stator assembly 127a is provided in the motor housing 123 a.

According to the three-phase alternating current motor, the heat exchange medium channel is arranged between the motor shell 123a and the stator assembly 127a and is connected with the heat exchange medium inlet 121a and the heat exchange medium outlet 126a, so that heat generated by the motor can be effectively absorbed by heat exchange medium in the heat exchange medium channel, the channel does not need to be arranged inside the motor shaft 125a or the stator assembly 127a, the structural influence on the motor is small, the implementation mode is simple, and the cost is low.

The device comprises a power supply module, a three-phase inverter, a stator assembly, a battery cooling circuit, a three-phase motor, a three-phase inverter, a power supply module, a three-phase coil, a heat exchange medium inlet and a stator assembly, wherein the power supply module is used for alternately charging the three-phase coil and discharging the three-phase coil by controlling the three-phase inverter, so that the three-phase inverter and the three-phase motor heat the heat exchange medium flowing through at least one of the three-phase inverter and the three-phase motor through the electric driving cooling circuit, the heat exchange medium flows into the heat exchange medium inlet of the three-phase motor, the stator assembly is used for heating the heat exchange medium in a heat exchange medium pipeline, and the heated heat exchange medium is used for increasing the temperature of a device to be heated when flowing through the battery cooling circuit.

The application provides a vehicle, lead out the neutral conductor in three-phase AC motor, and then with power battery, go up/step down module and three-phase inverter constitute different return circuits, through the inside three-phase coil of three-phase AC motor, three-phase inverter and go up/step down module and inside device that generates heat provide the heat source, realize the heating to power battery through former cooling circuit behind the heating coolant liquid, need not use the engine or increase heating device and just can realize promoting power battery's temperature, and heating efficiency is high, power battery temperature risees soon.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. A motor control circuit is characterized by comprising a voltage rising/reducing module, a three-phase inverter, a first switch module and a control module, wherein the three-phase alternating current motor, the three-phase inverter, the voltage rising/reducing module and a power supply module are sequentially connected, the power supply module is connected with the connection point of a three-phase coil in the three-phase alternating current motor through the first switch module, the power supply module supplies power to the voltage rising/reducing module and the three-phase alternating current motor, the power supply module is also connected with the three-phase inverter in a common way, the control module is respectively connected with the power supply module, the device to be heated, the voltage rising/reducing module, the three-phase alternating current motor and the three-phase inverter, transferring heat of at least one of the step-up/down module, the three-phase inverter, and the three-phase ac motor to the device to be heated through a heat exchange medium;

the voltage rising/reducing module comprises an energy storage unit and a seventh power switch unit, when the power supply module is a power battery, the first switch module, the three-phase alternating current motor and the three-phase inverter form a first current loop, and the three-phase alternating current motor, the three-phase inverter, the energy storage unit, the seventh power switch unit and the first switch module form a second current loop.

2. The motor control circuit of claim 1, wherein the buck-boost module further comprises an eighth power switch, the first terminal of the energy storage unit is the first terminal of the buck-boost module, the second terminal of the energy storage unit is connected to the second terminal of the seventh power switch unit and the first terminal of the eighth power switch, the first terminal of the seventh power switch unit is the second terminal of the buck-boost module, and the second terminal of the eighth power switch unit is the third terminal of the buck-boost module.

3. The motor control circuit according to claim 1, wherein a first end of the step-up/down module is connected to a positive terminal of the power supply module and a first end of the first switch module, a second end of the first switch module is connected to a connection point of three-phase coils of the three-phase ac motor, the three-phase coils of the three-phase ac motor are respectively connected to midpoints of three-phase arms of the three-phase inverter, the first end of the three-phase inverter is connected to the second end of the step-up/down module, and the second end of the three-phase inverter is connected to a negative terminal of the power supply module.

4. The motor control circuit of claim 3 wherein the first terminal of the energy storage unit is the first terminal of the buck/boost module, the second terminal of the energy storage unit is connected to the second terminal of the seventh power switch unit, and the first terminal of the seventh power switch unit is the second terminal of the buck/boost module.

5. The motor control circuit of claim 1 wherein the power module and the device to be heated are both power cells.

6. The motor control circuit of claim 1 wherein the power module is an external power module and the device to be heated is a power battery.

7. A heating method of a vehicle based on the motor control circuit of claim 1, characterized by comprising:

the control module obtains that the device to be heated controls the first switch module to be conducted when needing to be heated, and controls the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor to heat a heat exchange medium flowing through at least one of the voltage rising/reducing module, the three-phase inverter and the three-phase alternating current motor.

8. The heating method of claim 7, wherein the power module is a power battery; the device to be heated comprises a power battery;

the power battery, the first switching module, the three-phase alternating current motor and the three-phase inverter form a first current loop, and the three-phase alternating current motor, the three-phase inverter, the step-up/step-down module and the first switching module form a second current loop;

the controlling the step-up/down module, the three-phase inverter, and the three-phase ac motor to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter, and the three-phase ac motor includes:

and controlling the step-up/down module and the three-phase inverter to alternately conduct the first current loop and the second current loop so that the step-up/down module, the three-phase inverter and the three-phase alternating current motor generate heat to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor.

9. The heating method of claim 8, wherein the controlling the buck/boost module and the three-phase inverter to alternately conduct the first current loop and the second current loop comprises:

outputting PWM control signals to the voltage rising/reducing module and the three-phase inverter to enable the first current loop and the second current loop to be conducted alternately, obtaining actual charging current of the power battery, comparing the actual charging current with target charging current corresponding to preset heating power, and adjusting duty ratio of the PWM control signals according to comparison results to adjust the actual charging current to the target charging current.

10. The heating method according to claim 8, wherein the step-up/down module further comprises an eighth power switch, the first terminal of the energy storage unit is the first terminal of the step-up/down module, the second terminal of the energy storage unit is connected to the second terminal of the seventh power switch unit and the first terminal of the eighth power switch, the first terminal of the seventh power switch unit is the second terminal of the step-up/down module, and the second terminal of the eighth power switch unit is the third terminal of the step-up/down module;

the voltage rising/falling module and the power battery form a third current loop, and the second current loop and the third current loop form a first current loop group;

and controlling the step-up/down module and the three-phase inverter to alternately conduct the first current loop and the first current loop group so that the step-up/down module, the three-phase inverter and the three-phase alternating current motor generate heat to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor.

11. The heating method according to claim 7, wherein the device to be heated is a power battery;

the control module obtains when needing to heat the device of treating the heating control first switch module switches on, still includes:

the control module acquires a state signal of the three-phase alternating current motor and temperature information of a power battery;

when the three-phase alternating current motor is judged to be in a non-driving state and the temperature of the power battery is lower than a preset temperature value, controlling the first switch module to be conducted;

when the three-phase alternating current motor is judged to be in a non-driving state and the temperature of the power battery is not lower than a preset temperature value, re-acquiring a state signal of the three-phase alternating current motor and temperature information of the power battery;

the controlling the step-up/down module, the three-phase inverter, and the three-phase ac motor to generate heat to heat a heat transfer medium flowing through at least one of the step-up/down module, the three-phase inverter, and the three-phase ac motor further includes:

and controlling the first switch module to be switched off when the three-phase alternating current motor is in a driving state or the temperature of the power battery is not lower than a preset temperature value.

12. The heating method according to claim 7, wherein the power supply module includes an external power supply module and a second switching module, the second switching module connects the external power supply module, the first switching module, the step-up/down module, and the three-phase inverter, the external power supply module, the second switching module, the first switching module, the three-phase alternating-current motor, and the three-phase inverter form a fourth current loop, and the step-up/down module, the three-phase alternating-current motor, the first switching module, and the three-phase inverter form a second current loop;

and controlling the step-up/down module and the three-phase inverter to alternately conduct a fourth current loop and the second current loop so that the step-up/down module, the three-phase inverter and the three-phase alternating current motor generate heat to heat a heat exchange medium flowing through at least one of the step-up/down module, the three-phase inverter and the three-phase alternating current motor.

13. The heating method according to claim 12, wherein the device to be heated is a power battery;

the obtaining of controlling the conduction of the first switch module and the second switch module when the device to be heated needs to be heated further includes:

acquiring a state signal of the three-phase alternating current motor and temperature information of a power battery;

when the three-phase alternating current motor is judged to be in a non-driving state and the temperature of the power battery is lower than a preset temperature value, controlling the first switch module and the second switch module to be conducted;

14. A vehicle characterized by further comprising the motor control circuit of any one of claims 1 to 6.

15. The vehicle of claim 14, wherein the three-phase ac motor includes a motor shaft, a stator assembly, and a motor housing, the stator assembly is coupled to the motor shaft, the stator assembly is disposed in the motor housing, the motor housing has a heat exchange medium inlet and a heat exchange medium outlet, a heat exchange medium passage is disposed between the motor housing and the stator assembly, and the heat exchange medium passage is coupled to the heat exchange medium inlet and the heat exchange medium outlet.