WO2022021450A1 - 电机、动力系统、控制方法以及电动汽车 - Google Patents

电机、动力系统、控制方法以及电动汽车 Download PDF

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Publication number
WO2022021450A1
WO2022021450A1 PCT/CN2020/106473 CN2020106473W WO2022021450A1 WO 2022021450 A1 WO2022021450 A1 WO 2022021450A1 CN 2020106473 W CN2020106473 W CN 2020106473W WO 2022021450 A1 WO2022021450 A1 WO 2022021450A1
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WIPO (PCT)
Prior art keywords
winding set
motor
winding
inverter
magnetic field
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PCT/CN2020/106473
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English (en)
French (fr)
Inventor
黄孝键
左希阳
但志敏
李宝
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宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to CN202080073217.9A priority Critical patent/CN114555415A/zh
Priority to PCT/CN2020/106473 priority patent/WO2022021450A1/zh
Priority to EP20946739.8A priority patent/EP4043275A4/en
Publication of WO2022021450A1 publication Critical patent/WO2022021450A1/zh
Priority to US17/878,368 priority patent/US20220368262A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/51—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells characterised by AC-motors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/25—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by controlling the electric load
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/27—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by heating
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/28—Layout of windings or of connections between windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
    • H02P25/22—Multiple windings; Windings for more than three phases
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/60—Controlling or determining the temperature of the motor or of the drive
    • H02P29/62—Controlling or determining the temperature of the motor or of the drive for raising the temperature of the motor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2220/00—Electrical machine types; Structures or applications thereof
    • B60L2220/50—Structural details of electrical machines
    • B60L2220/56—Structural details of electrical machines with switched windings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/425—Temperature

Definitions

  • the present application relates to the field of electric vehicles, and more particularly, to a motor, a power system, a control method, and an electric vehicle.
  • An electric vehicle is a vehicle powered by a power battery. Due to the limitation of the power battery material, it can stably exert the best performance at the rated cell temperature. Therefore, when using electric vehicles in areas with low cell temperature, the power battery needs to be heated to the rated cell temperature.
  • Indirect heating refers to placing a heat source outside the power battery for heating.
  • Direct heating refers to heating the power battery inside the power battery.
  • a direct heating method is proposed in the industry to heat the power battery through a motor.
  • the present application provides a motor, a power system, a control method, and an electric vehicle, aiming to solve the technical problems that the rotor generates a large amount of heat and the NVH index of the motor does not meet the standard when the motor works to provide heating current for the power battery.
  • the present application provides a motor, including: an N-phase first winding set and an N-phase second winding set, where N is a positive integer, and the motor is used to heat a power battery;
  • the first winding set and the second winding set are energized, so that the direction of the magnetic field generated by the first winding set has a phase difference with the direction of the magnetic field generated by the second winding set.
  • the total magnetic flux of the magnetic field generated by the secondary winding set is within a preset magnetic flux threshold range.
  • the stator winding of the motor includes two sets of sub-winding sets.
  • the two sets of sub-winding sets are both supplied with current, so that there is a phase difference between the magnetic fields generated by the two sets of sub-winding sets.
  • the magnetic fields generated by the sub-winding sets cancel each other out, so that the magnetic field strength in the stator windings is reduced, and the air-gap magnetic flux is reduced, so as to reduce motor heating and motor NVH problems.
  • the first winding set and the second winding set are located in the same stator slot.
  • the magnetic field generated by the first winding set and the magnetic field generated by the second winding set are in opposite directions, thereby reducing the air gap magnetic flux and reducing the motor heating and NVH problems.
  • the first winding set and the second winding set are located in adjacent stator slots.
  • the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the two magnetic fields partially cancel each other, thereby achieving the purpose of reducing the air gap magnetic flux.
  • the first winding set is located at the slot bottom of the stator slot and the second winding set is located at the slot opening of the stator slot.
  • the phase difference between the current flowing into the first winding set and the current in the second winding set is within a preset phase threshold, and the amplitude difference between the two is within a preset amplitude threshold.
  • the difference between the generated magnetic field and the magnetic field generated by the second winding set is there is a phase difference, and the amplitude difference between the two is within a preset amplitude threshold, so as to achieve the purpose of reducing the total air gap magnetic flux.
  • the present application provides a power system, including: a power battery, a conversion module, and a motor involved in the first aspect and the optional solution;
  • the DC side of the conversion module is connected to the positive and negative electrodes of the power battery, the first AC side of the conversion module is connected to the first winding set, and the second AC side of the conversion module is connected to the second winding set.
  • the conversion module includes a three-leg inverter
  • the DC side of the three-arm inverter is connected to the positive and negative electrodes of the power battery
  • the AC side of the three-arm inverter is connected to the first winding set
  • the switch assembly is connected to the three-arm inverter. between the AC side and the second winding set.
  • the conversion module includes two three-leg inverters
  • the DC sides of the two three-arm inverters are both connected to the positive and negative electrodes of the power battery, the AC side of one three-arm inverter is connected to the first winding set, and the other three-arm inverter is connected to the first winding set.
  • the AC side of the device is connected to the second winding set.
  • the conversion module includes a six-leg inverter, and the six-leg inverter includes two AC sides;
  • the DC side of the six-arm inverter is connected to the positive and negative electrodes of the power battery, one AC side of the six-arm inverter is connected to the first winding set, and the other AC side of the six-arm inverter is connected to the first winding set. side is connected to the second winding set.
  • the second winding set and the neutral point of the first winding set are connected.
  • the present application provides a heating control method, the method is applied to a power system, the power system includes a motor, an inverter and a power battery, the method is executed on a controller of the motor, and the method includes:
  • the judgment result is yes, make the power battery energize the first winding set and the second winding set, so that the direction of the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the first winding set and the second winding set have a phase difference.
  • the total magnetic flux of the magnetic field generated by the secondary winding set is within a preset magnetic flux threshold range.
  • the inverter includes a switch assembly; energizing the first winding set and the second winding set includes:
  • the present application provides an electric vehicle, including a power system, where the power system includes: a power battery, a conversion module, and the motor involved in the first aspect and the optional solution.
  • the present application provides a motor, a power system, a control method, and an electric vehicle.
  • the motor is connected to a power battery through a conversion unit.
  • the stator winding of the motor includes two sets of sub-winding sets. When the power battery needs to be heated, the two sets of sub-winding sets are connected to each other. Incoming current, there is a phase difference between the magnetic fields generated by the two sets of sub-winding sets, and the magnetic fields generated by the two sets of sub-winding sets cancel each other out, reducing the magnetic field strength in the stator windings and the air-gap magnetic flux to reduce motor heating and motor NVH problems.
  • 1 is a schematic circuit diagram of a power system of an electric vehicle provided by the application;
  • FIG. 2 is a schematic structural diagram of a power battery provided by the application.
  • FIG. 3 is a schematic structural diagram of a motor provided by an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of a motor provided by another embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a power system provided by another embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a power system provided by another embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a power system provided by another embodiment of the present application.
  • FIG. 8 is a schematic structural diagram of a power system provided by another embodiment of the present application.
  • FIG. 9 is a schematic structural diagram of a power system according to another embodiment of the present application.
  • An electric vehicle is a vehicle powered by a power battery.
  • a power system 100 of an electric vehicle includes a power battery 10 , an inverter 20 , a motor 30 , and a motor controller (Motor Controller Unit, MCU for short) 40 .
  • the positive and negative electrodes of the power battery 10 are connected to the DC side of the inverter 300 , and the AC side of the inverter 20 is connected to the stator windings of the motor 30 .
  • the power battery 10 supplies power to the motor 30 through the inverter 20, and the motor outputs power to drive the vehicle.
  • the MCU 40 is provided with a plurality of input terminals for receiving motor running state data and motor control commands.
  • the MCU 40 generates a pulse width modulation (Pulse Width Modulation, PWM for short) signal according to the motor control command, the motor running status data and the power battery running status data, and controls the inverter to provide voltage and current to the motor 30 to control the motor speed , in order to realize the vehicle speed control.
  • PWM Pulse Width Modulation
  • the power battery 100 includes a battery module 101 , an auxiliary structure 102 and a battery management system 103 .
  • the battery module 101 is formed by a plurality of power cells in series and parallel.
  • the power cells are the core components of the power battery and are the source of the power battery to provide electrical energy.
  • the auxiliary structure 102 includes an outer frame, fixing means, electrical connection means and insulating parts.
  • the outer frame plays the role of protecting and supporting the battery module
  • the electrical connection device plays the role of connecting other electrical equipment, such as connecting with the inverter
  • the insulating part plays the role of insulating protection.
  • the main functions of the battery management system 103 are charge and discharge management, high voltage control, battery status evaluation, battery data collection, battery protection, and battery thermal management.
  • the thermal management function in the battery management system 103 is used to ensure that the power battery operates within a suitable temperature range.
  • the main function of the battery thermal management system is to accurately measure and monitor the battery temperature. When the temperature of the battery pack is too high, it can effectively dissipate heat. When the temperature is too low, such as below the temperature threshold, it can perform rapid heating and ensure the uniform distribution of the battery pack temperature field. Among them, due to the limitation of the power battery material, it can stably exert the best performance at the rated cell temperature. Therefore, when using in an environment with a low cell temperature, the power battery needs to be heated to the rated cell temperature.
  • Indirect heating refers to placing a heat source outside the power battery for heating. Indirect heating methods may be air heating, liquid heating, and heating film heating, among others. Different heating sources, the heating rate of the battery will be different. Since the battery is heated by an external heat source, heat loss will be generated on the heat transfer medium, so the efficiency of indirect heating is not high.
  • Direct heating refers to heating the power battery internally. At present, a direct heating method is proposed in the industry to heat the power battery through a motor.
  • NVH is the abbreviation of Noise, Vibration and Harshness, which respectively represent noise, vibration and harshness. NVH is an important indicator to measure the comfort of a car.
  • the present application provides a motor, a power system, a control method and an electric vehicle, aiming at solving the above problems.
  • the inventive concept of the present application is as follows: when the battery is directly heated by the motor, the conventional operating conditions of the motor are changed, resulting in extremely uneven distribution of the magnetic flux density in the air gap of the motor under this operating condition, so that the rotor heats up seriously and cannot be Maintaining the heating condition for a long time also causes the motor NVH problem. Based on the above analysis, the present application sets two sets of stator windings.
  • the two sets of windings or any one of them, or two sets of windings work at the same time and the total magnetic field flux generated by the two sets of windings is greater than any
  • the magnetic flux generated by a set of windings interacts with the magnetic field generated by the rotor to output power.
  • current is passed into the two sets of windings, so that there is a phase difference between the magnetic fields generated by the two sets of windings, and the magnetic fields generated by the two sets of windings cancel each other out, so that the magnetic field strength in the stator windings is reduced, and the air gap magnetic flux reduced to reduce motor vibration and rotor heating.
  • the vibration of the motor is related to the magnetic flux density and uneven distribution of the air gap. Due to the reduction of the magnetic flux density of the air gap, the NVH problem of the motor caused by the uneven distribution of the magnetic field has also been suppressed to a certain extent at the source.
  • the structure of the motor provided by an embodiment of the present application is described below.
  • the motor provided by the present application includes: an N-phase first sub-winding set, an N-phase second sub-winding set, a stator core, and a rotor.
  • N is a positive integer
  • the motor is used to heat the power battery and can also be used to provide power.
  • the first sub-winding set and the second sub-winding set are wound on the stator iron core, and the windings may be centralized windings or distributed windings, which are not limited here.
  • the first winding set and the second winding set are energized, so that the direction of the magnetic field generated by the first winding set has a phase difference with the direction of the magnetic field generated by the second winding set.
  • the total magnetic flux of the magnetic field generated by the second winding set is within a preset magnetic flux threshold range.
  • the preset magnetic flux threshold range is greater than 0, and is smaller than any value of the magnetic field magnetic flux generated by the first winding set and the magnetic field magnetic flux generated by the second winding set.
  • the two sub-winding sets When the motor heats the power battery, the two sub-winding sets generate a magnetic field with a phase difference, the two magnetic fields cancel each other, and the total magnetic field is controlled within a reasonable range, so that the use of the motor to heat the power battery can meet the NVH requirements. .
  • the requirements for the difficulty of motor control can also be reduced.
  • the second winding set and the first winding set are located in the same stator slot, the first winding set is located at the bottom of the slot of the stator slot, and the second winding set is located at the slot of the stator slot,
  • the arrangement of windings located in the same stator slot can be achieved without reducing the output power of the motor.
  • first winding set and the second winding set may be arranged in adjacent stator slots, and the original structure of the stator slots may not be changed.
  • Both the first winding set and the second winding set are used for connecting with the power battery through the conversion module, so as to realize electric energy transmission between the motor and the power battery.
  • the motor can also output power.
  • the alternating current can only be fed into the first winding set, and the first winding set generates a magnetic field, which interacts with the rotor to generate a magnetic field to output power to the outside.
  • the alternating current can also be supplied to the first winding set and the second winding set at the same time, and the magnetic field is jointly generated by the first winding set and the second winding set.
  • both the first winding set and the second winding set are energized, the rotor is in a locked-rotor state, and the rotor is fixed, so that the first winding set and the second winding set are used as energy storage elements to provide power to the power battery.
  • the current is changed to realize the heating of the power battery by its own internal resistance.
  • both the first winding set and the second winding set energize both the first winding set and the second winding set, and make the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, the magnetic fields generated by the two sub-windings cancel each other, and the magnetic field generated by the stator winding
  • the total magnetic field approaches zero, the air gap flux density decreases, and the flux density on the rotor also decreases.
  • the first winding set is located at the bottom of the slot of the stator slot, and the second winding set is located at the notch of the stator slot, under the heating condition
  • the direction of the current to the first winding set is opposite to that of the current flowing into the second winding set
  • the direction of the magnetic field generated by the first winding set and the magnetic field generated by the second winding set are opposite, so as to reduce the air gap magnetic flux, Reduce motor heating and NVH issues.
  • the first winding set when the first winding set and the second winding set are arranged in adjacent stator slots, under the heating condition, when the current to the first winding set and the current flowing into the second winding set, the first winding set is The directions of the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the total magnetic flux generated by the first winding set and the second winding set is controlled to be within a preset magnetic flux threshold range, and the preset magnetic flux threshold range is smaller than the third The magnetic flux of the magnetic field generated by either one of the first winding set and the second winding set.
  • the total magnetic flux generated by the first winding set and the second winding set is set at a preset magnetic flux threshold value. within the range.
  • the preset magnetic flux threshold is determined according to the maximum heating temperature of the rotor and the maximum vibration noise of the rotor, and the total magnetic flux is within the preset magnetic flux threshold range, so as to control the rotor heat generation and vibration noise within the allowable range.
  • the winding directions of the first winding set and the second winding set can be different or the same, and there can also be a phase difference.
  • the phase difference value of the current passed into the first winding set and the second winding set to be within a preset phase threshold
  • the amplitude difference between the two is within the preset amplitude threshold, so that the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference and a difference in amplitude, and the magnetic field generated by the two stator windings They cancel each other out, and the total magnetic flux generated by the first winding set and the second winding set is within the preset magnetic flux threshold range.
  • the phase difference between the current passing through the first winding set and the current passing through the second winding set is within a preset phase threshold, and controlling the current passing through the first winding set and the current passing through the second winding set
  • the amplitude difference between the currents of the sets is within the preset amplitude threshold, so as to achieve the purpose of controlling the total magnetic flux generated by the first winding set and the second winding set to be within the threshold range.
  • the total magnetic flux generated by the first winding set and the second winding set can be controlled within the preset magnetic flux within the threshold range.
  • the number of winding turns of the first winding set and the second winding set may be different, which is a quantity related to the degree of heating of the rotor and the vibration noise.
  • the specific number of turns calculation formula is as follows:
  • E ⁇ 1 is the phase potential amplitude of the first winding set
  • E ⁇ 2 is the phase potential amplitude of the second winding set.
  • phase potential amplitude of the first winding set and the phase potential amplitude of the second winding set satisfy the following formula:
  • ⁇ is the conduction angular frequency
  • ⁇ m is the air gap magnetic flux density threshold, which is determined according to the maximum allowable rotor heat generation and the maximum vibration noise.
  • the combined magnetic field of the first winding collecting magnetic field and the second winding collecting magnetic field can be controlled within a required threshold range. For example, by controlling the wire diameter of the first winding set and the second winding set to be the same, the number of turns of the windings to be the same, and the winding directions to be opposite, the magnetic flux of the synthetic magnetic field can be made to approach zero.
  • the first winding set and the second winding set are wound with the same wire, the first winding set has the same number of turns as the second winding set, and the winding directions are opposite, and the first winding The phase of the alternating current passing through the collector and the second winding is the same, so that the concentrated magnetic field of the first winding and the concentrated magnetic field of the second winding can be completely cancelled, the magnetic flux density of the air gap tends to zero, and the rotor heat generation can tend to zero.
  • PC is the rotor eddy current loss
  • K C is the eddy current loss coefficient
  • f is the current frequency
  • B S is the rotor magnetic flux density amplitude.
  • the rotor eddy current loss is proportional to the square of the rotor magnetic flux density.
  • the weakening of the rotor magnetic flux density and the reduction of the rotor eddy current loss in a square relationship can solve the problem of rotor temperature rise, and then solve the problem of self-heating failure. problem with prolonged use.
  • the motor vibration is related to the non-uniform magnetic flux density and distribution of the air gap, the air gap magnetic flux density tends to 0, and the problem of motor vibration and noise caused by the non-uniform magnetic field distribution is obtained.
  • the magnetic fields generated by the first winding set and the second winding set have a phase difference, and the magnetic fields cancel each other, so that the magnetic field strengths in the stator windings of each phase approach At zero, the air-gap magnetic flux is reduced to reduce motor vibration and rotor heating, and can meet the NVH requirements in the process of using the motor to heat the power battery.
  • the difficulty of motor control can be further reduced by setting the stator winding current and winding method to overcome the NVH problem.
  • a motor 200 provided by another embodiment of the present application includes a three-phase symmetrical first winding set 201 , a three-phase symmetrical second winding set 202 , a stator iron core 203 , and a rotor.
  • the three-phase symmetrical first winding set 201 and the three-phase symmetrical second winding set 202 are both wound on the stator core 203 and located in the same stator slot.
  • the winding directions of the first winding set and the second winding set are opposite, may be the same, or may have a phase difference.
  • the number of turns of the first winding set 201 is a1, which are denoted as A1, B1, and C1, respectively;
  • the number of turns of the second winding set 202 is a2, which is denoted as A2, B2, and C2, respectively.
  • the neutral points of the first winding sets A1, B1, C1 and the neutral points of the second winding sets A2, B2, C2 are not connected.
  • the first winding set A1, B1, C1 and the second winding set A2, B2, C2 are respectively connected to the two AC sides of the conversion unit.
  • the three-phase first winding set is wound in a conventional winding manner.
  • the winding methods of the first winding set and the second winding set are illustrated by taking the opposite winding directions of the first winding set and the second winding set as an example: place the A2 phase winding and the C1 phase winding in the same slot; place the C2 phase winding in the same slot; The phase winding and the A1 phase winding are placed in the same slot; the B2 phase winding and the B1 phase winding are placed in the same slot.
  • the first winding set is distributed along the circumference as A1 ⁇ B1 ⁇ C1
  • the corresponding second winding set is distributed along the circumference as C2 ⁇ B2 ⁇ A2. In this wiring manner, when currents are passed in the same direction, the first winding set and the second winding set generate opposite magnetic fields.
  • the phase and amplitude of the current flowing into the first winding set and the second winding set can be controlled, so that the magnetic field generated by the first winding set and the The magnetic fields generated by the two winding sets have a phase difference, and the magnetic fields generated by the two stator windings cancel each other out.
  • the three-phase symmetrical first winding set 201 and the three-phase symmetrical second winding set 202 are located in adjacent stator slots. Moreover, the winding directions of the first winding set and the second winding set are opposite, and may be the same, and may also have a phase difference. The phase and amplitude of the current flowing into the first winding set and the second winding set can be controlled, so that the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the magnetic fields generated by the two stator windings cancel each other.
  • the first winding set and the second winding set are energized, so that the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the magnetic fields generated by the two sub-windings cancel each other out , so that the total magnetic field generated by the stator windings tends to zero, thereby reducing the air-gap magnetic flux density, and the magnetic density on the rotor will also become very small.
  • the first winding set and the second winding set when the motor works in the heating condition, the first winding set and the second winding set generate opposite magnetic fields, and the magnetic fields cancel each other, so that the magnetic field strength in the stator winding of each phase tends to zero , thereby reducing the air-gap magnetic flux to reduce motor vibration and rotor heating.
  • a power system provided by another embodiment of the present application includes: a power battery 100, a conversion module 300, and a motor.
  • the electric machine includes a three-phase first winding set 201 and a three-phase second winding set 202 , and only the stator windings are shown in FIG. 3 .
  • the conversion module 300 includes one DC side and two AC sides.
  • the DC side of the conversion module 300 is connected to the positive and negative electrodes of the power battery 100 respectively.
  • One of the AC sides of the conversion module 300 is connected to the first winding set 201 .
  • the other AC side is connected to the second winding set 202 .
  • the conversion module 300 works in the inverter state, converts the direct current output from the power battery into alternating current, and provides alternating current excitation for the motor.
  • the conversion module 300 acts as a part of the heating circuit, and the stator winding of the motor acts as an energy storage element to provide alternating current to the power battery.
  • the power battery when the motor outputs power to the outside, the power battery only supplies power to the first winding set through the control conversion module, and the first winding set generates a magnetic field, which interacts with the rotor to generate a magnetic field to output power to the outside. . It is also possible to energize both the first winding set and the second winding set, and the magnetic field generated by the first winding set and the second winding set is superimposed and enhanced, and the magnetic field interacts with the rotor to output power to the outside.
  • the first winding set and the second winding set are energized by the control conversion module, and the magnetic field generated by the first winding set and the magnetic field generated by the second winding set have a phase difference, and the two sub-windings
  • the generated magnetic fields cancel each other out, so that the total magnetic field generated by the stator windings approaches zero, the air-gap magnetic flux density decreases, and the magnetic density on the rotor becomes very small.
  • the fixing of the rotor includes controlling the motor rotor to be locked and the motor rotor to be in a relatively static state, that is, the motor rotor rotates very little, and the rotation deviation within the range.
  • both the first winding set and the second winding set of the motor are energized, and the magnetic fields generated by the two stator windings cancel each other, so that the air gap magnetic flux density is reduced, and the magnetic density on the rotor will also become very small, so that the Reduce motor vibration and rotor heating.
  • a power system provided by another embodiment of the present application includes: a power battery 100, a conversion module 300, and a motor.
  • the electric machine includes a three-phase first winding set 201 and a three-phase second winding set 202 .
  • the conversion module 300 includes a three-arm inverter and a switch assembly.
  • the first bridge arm is composed of power tubes V1 and V4
  • the second bridge arm is composed of power tubes V2 and V5
  • the second bridge arm is composed of power tubes V3 and V6.
  • the DC side of the inverter is connected to the positive and negative electrodes of the power battery 100
  • the AC side of the inverter is connected to the first winding set 201
  • the switch assembly is connected between the AC side of the inverter and the second winding set 202
  • the switch assembly includes a switch S1, a switch S2, and a switch S3.
  • the winding directions of the three-phase first winding set 201 and the three-phase second winding set 202 may be the same or opposite, and there may also be a phase difference.
  • the current direction, current phase and current amplitude in the three-phase first winding set 201 and the three-phase second winding set 202 are controlled, so that the three-phase first winding set 201 and the three-phase second winding set 202 are controlled.
  • a magnetic field that can be cancelled is generated in the first winding set 201 and the three-phase second winding set 202 .
  • the switch assembly When the motor outputs power to the outside, the switch assembly can be disconnected, the pulse width modulation signal PWM signal can be input to the bridge arm control end of the inverter, only the first winding set is energized, and the magnetic field is generated by the first winding set. It interacts with the rotor to generate a magnetic field to output power to the outside.
  • the switch assembly can also be closed, and the PWM signal is input to the bridge arm control end of the inverter to energize both the first winding set and the second winding set, so that the first winding set and the second winding set are energized.
  • the concentrated magnetic fields of the two windings have the same direction, so that the superposition of the magnetic fields of the first winding set and the second winding set is enhanced.
  • the first winding set and the second winding set jointly generate an enhanced magnetic field, which interacts with the rotor to generate a magnetic field to output power to the outside.
  • the switch assembly can also be closed, and the PWM signal is input to the bridge arm control end of the inverter to energize both the first winding set and the second winding set, so that the first winding set and the second winding set are energized.
  • the concentrated magnetic field of the second winding has a phase, and the total magnetic field of the first winding set and the second winding set is greater than the first winding set to generate a magnetic field, or greater than the second winding set to generate a magnetic field. That is, the total magnetic field of the first winding set and the second winding set is superimposedly enhanced. In order to realize that the first winding set and the second winding set jointly generate an enhanced magnetic field, which interacts with the rotor to generate a magnetic field to output power to the outside.
  • the switch assembly When the motor heats the power battery, the switch assembly is closed, and the pulse width modulation signal PWM signal is input to the bridge arm control end of the inverter to energize the first winding set and the second winding set, and the magnetic field generated by the first winding set There is a phase difference with the magnetic field generated by the second winding set, the magnetic fields generated by the two sub-windings cancel each other, the total magnetic field generated by the stator windings approaches zero, the air-gap magnetic flux density decreases, and the magnetic density on the rotor also becomes very high. Small, motor vibration and rotor heating are correspondingly reduced.
  • control signal of the bridge arm control end is not limited to be a PWM signal, and may also be other signals capable of controlling the bridge arm.
  • the motor heats the power battery
  • the first winding set and the second winding set are wound in opposite directions
  • the PWM signal turns on and off the power tubes V1, V5 and V6, and the switch components S1, S2, S3 are closed as an example , describe the process of charging the battery with the first winding set and the second winding set as energy storage elements in the motor.
  • the power battery discharges and converts the electric energy into the electromagnetic energy on the stator inductances of A-phase, B-phase and C-phase, and the stator inductance stores energy.
  • the size of the heating current in the loop is determined by the closing time of the power tubes V1, V5 and V6, that is, the frequency f and the duty cycle D of the signals driving the power tubes V1, V5 and V6.
  • the power tubes V1, V5 and V6 are disconnected at the same time.
  • the charging circuit of the power battery is formed as follows: C1 phase stator inductance ⁇ crystal diode D3 ⁇ Power battery ⁇ crystal diode D4 ⁇ A1 phase stator inductance, and B1 phase stator inductance ⁇ crystal diode D2 ⁇ power battery ⁇ crystal diode D4 ⁇ A1 phase stator inductance.
  • the power tubes V1, V5 and V6 are turned on, and the switch S1, switch S2, and switch S3 are turned on.
  • the auxiliary energizing circuit of the second winding set is similar to the first winding set: power battery ⁇ power tube V1 ⁇ switch S1 ⁇ A2 phase stator inductance ⁇ B2 phase stator inductance ⁇ switch S2 ⁇ power tube V5 ⁇ power battery, and power battery ⁇ power tube V1 ⁇ switch S1 ⁇ A2 phase stator inductance ⁇ C2 phase stator inductance ⁇ switch S3 ⁇ power tube V6 ⁇ Power battery, in this process, the power battery discharges and converts the electric energy into electromagnetic energy on the A-phase, B-phase and C-phase stator inductance, the stator inductance stores energy, and the heating current in the loop is determined by the power tubes V1, V5 The closing time of V6 and V6 is determined by the frequency f and the duty cycle D of the driving V1, V5 and V6 signals
  • the power tubes V1, V5 and V6 are disconnected at the same time. Due to the characteristic that the current in the inductor cannot change abruptly, at this time, the auxiliary charging circuit of the power battery is formed as follows: C2 phase stator inductance ⁇ power tube S3 ⁇ crystal diode D3 ⁇ power Battery ⁇ crystal diode D4 ⁇ switch S1 ⁇ A2 phase stator inductance, and B2 phase stator inductance ⁇ switch S2 ⁇ crystal diode D2 ⁇ power battery ⁇ crystal diode D4 ⁇ switch S1 ⁇ A1 phase stator inductance.
  • the second winding set passes current, since the winding direction of the second winding set is opposite to the winding direction of the second sub-winding set, a magnetic field direction opposite to the first winding set will be generated, and the amplitude change will be the same as that of the first winding set. Generates a magnetic field with uniform changes in magnetic field amplitude. At this time, the combined magnetic field of the first winding collecting magnetic field and the second winding collecting magnetic field will be significantly reduced.
  • the wire diameter or the number of winding turns of the first winding set and the second winding set the combined magnetic field of the first winding collecting magnetic field and the second winding collecting magnetic field can be controlled within a required threshold range. For example, by controlling the wire diameter of the first winding set and the second winding set to be the same, the number of turns of the windings to be the same, and the winding directions to be opposite, the magnetic flux of the synthetic magnetic field can be made to approach zero.
  • both the first winding set and the second winding set of the motor are energized, so that the air-gap magnetic flux density is reduced, and the magnetic density on the rotor becomes very small, so as to reduce motor vibration and rotor heating.
  • a power system provided by another embodiment of the present application includes: a power battery 100, a conversion module 300, and a motor.
  • the electric machine includes a three-phase first winding set 201 and a three-phase second winding set 202 .
  • the conversion module 300 includes two three-arm inverters 301 .
  • the DC sides of the two inverters 301 are both connected to the positive and negative poles of the power battery 100 , the AC side of one inverter 301 is connected to the first winding set 201 , and the AC side of the other inverter 301 is connected to the second winding set 201 .
  • the winding set 202 is connected.
  • the bridge arm control end of the inverter connected to the first winding set inputs the pulse width modulation signal PWM signal, and only the first winding set is energized, and the first winding set is energized.
  • a winding set generates a magnetic field, interacts with the rotor to generate a magnetic field, and outputs power to the outside. It is also possible to energize both the first winding set and the second winding set to jointly generate a magnetic field by the first winding set and the second winding set. This has been described in detail in the embodiment shown in FIG. 6 , and will not be repeated here.
  • the pulse width modulation signal PWM signal is input to the bridge arm control terminals of the two inverters, and the first winding set and the second winding set are energized, and the magnetic field generated by the first winding set and the second winding set.
  • the magnetic field generated by the winding set has a phase difference, the magnetic fields generated by the two sub-windings cancel each other out, the total magnetic field generated by the stator windings approaches zero, the air-gap magnetic flux density decreases, and the magnetic density on the rotor becomes very small. Vibration and rotor heating are correspondingly reduced.
  • inverters are respectively provided for the first winding set and the second winding set.
  • the bridge arm control terminals of the two inverters are controlled to make the Both the first and second winding sets of the motor are energized to reduce motor vibration and rotor heating.
  • a power system provided by another embodiment of the present application includes: a power battery 100, a conversion module 300, and a motor.
  • the electric machine includes a three-phase first winding set 201 and a three-phase second winding set 202 .
  • the conversion module 300 includes a six-arm inverter, and the midpoint of the first three arms constitutes one of the inverters On the AC side, the midpoint of the last three bridge arms constitutes the other AC side of the inverter.
  • the DC side of the inverter is connected to the positive and negative electrodes of the power battery 100 , one AC side of the inverter is connected to the first winding set 201 , and the other AC side of the inverter is connected to the second winding set 302 .
  • the neutral points of the second winding set and the first winding set may be connected to each other, as shown in FIG. 8 .
  • the pulse width modulation signal PWM signal is input to the control terminals of all bridge arms, and the first winding set and the second winding set are energized, and the magnetic field generated by the first winding set and the second winding set are generated.
  • the magnetic field has a phase difference, the magnetic fields generated by the two sub-windings cancel each other out, the total magnetic field generated by the stator windings approaches zero, the air-gap magnetic flux density decreases, and the magnetic density on the rotor becomes very small, resulting in motor vibration and rotor heating. also decreased accordingly.
  • the inverter has six bridge arms, the midpoints of the three bridge arms are connected to the first winding set, and the midpoints of the other three bridge arms are connected to the second winding set.
  • both the first winding set and the second winding set of the motor are energized to reduce motor vibration and rotor heating.
  • phase difference of the windings, the arrangement and on-off of the switches can be controlled to control the currents of the first winding set and the second winding set
  • the phase difference and the amplitude of the current are achieved so that the combined magnetic field of the first winding set and the second winding set is within a preset magnetic flux range.
  • Another embodiment of the present application further provides an electric vehicle, including the power system provided by the above embodiment.
  • an electric vehicle including the power system provided by the above embodiment.
  • the heating control method includes:
  • the temperature of the battery cell is monitored at any time.
  • the power battery includes a battery management system
  • the battery management system obtains the temperature of the electric power battery and sends the battery temperature information to the motor controller, wherein the motor includes the motor controller.
  • the motor controller receives temperature information from the battery.
  • the motor controller further receives the operating state information of the motor, where the operating state information of the motor includes the temperature of the motor stator, the temperature of the motor stator winding, the motor is in the working condition of heating the power battery, and the motor is in the external output state.
  • the working condition of the power, the motor is in a locked-rotor state and/or the motor is in a stopped working state, which are not specifically limited here.
  • S402 determine whether the temperature and operation state of the battery cells meet the heating conditions of the power battery, if so, go to S403 , otherwise, go to S404 or make the motor stop working.
  • the power battery heating condition includes that the temperature of the battery cell is less than a preset temperature threshold, and the operating state of the motor rotor is a locked-rotor state.
  • the preset temperature threshold is determined according to the rated operating temperature of the power battery.
  • the heating condition includes that the temperature of the cells of the power battery is lower than a preset temperature threshold, and the operating state of the motor is a stop working state.
  • the heating conditions include that the cell temperature of the power battery is lower than a preset temperature threshold, the running state of the motor is a locked-rotor state, and the temperature of the motor stator and the temperature of the motor stator winding are lower than the preset motor temperature threshold, the preset Set the motor temperature threshold to be determined according to the rated operating temperature of the power battery.
  • heating conditions can be set as required, which is not limited here.
  • the preset magnetic flux threshold range is smaller than the total magnetic flux generated by the first winding set, and the preset magnetic flux threshold range is also smaller than the total magnetic flux generated by the first winding set, that is, the magnetic field generated by the first winding set and the second winding set are generated.
  • the magnetic fields generated by the first winding set and the magnetic field generated by the second winding set reduce the total magnetic field, the air gap magnetic density, the heat generation, and the vibration correspondingly.
  • the conversion module includes a three-arm conversion module and a switch assembly, and the first winding set and the second winding set have opposite winding directions, the switch assembly is closed, and a PWM signal is input to the bridge arm control end of the conversion module to realize the The first winding set and the second winding set pass an alternating current, and it is ensured that the direction of the magnetic field generated by the first winding set has a phase difference with the magnetic field generated by the second winding set.
  • the conversion module includes two inverters with three bridge arms
  • PWM signals are input to the control terminals of all bridge arms of the two conversion modules, and the PWM signals input to the control terminals of the two inverters are different, so that the first winding set generates The direction of the magnetic field is out of phase with the magnetic field produced by the second winding set.
  • the conversion module includes an inverter with six bridge arms
  • S404 Pass current into the first winding set or the second winding set, or pass an alternating current into the first winding set and the second winding set, and the total magnetic flux generated by the first winding set and the second winding set is greater than a preset value within the magnetic flux threshold.
  • the first winding set or the second winding set when the power battery heating condition is not satisfied, only the first winding set or the second winding set is energized, and the total magnetic flux generated by the first winding set and the second winding set is greater than the preset magnetic flux threshold range, so that the first winding set
  • the generated magnetic field and the magnetic field generated by the second winding set are superimposed and strengthened, and the magnetic field generated by the first winding set and the magnetic field generated by the second winding set work together with the rotor. Due to the strengthening of the magnetic field, the output power of the motor is large, which can provide power to the outside.
  • the arrangement and on-off of the switches can be controlled to control the winding of the first winding set and the second winding set.
  • the phase difference of the current and the amplitude of the current are such that the combined magnetic field of the first winding set and the second winding set is within a preset magnetic flux range.
  • the first winding set and the second winding set of the motor are energized by controlling the conversion unit, and the first winding set and the second winding set are controlled by controlling the first winding set and the second winding set.
  • the magnetic flux of the magnetic field is within the preset magnetic flux threshold range to reduce motor vibration and rotor heating.

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Abstract

一种电机、动力系统、控制方法以及电动汽车，电机（30）包括：N相第一绕组集（201）以及N相第二绕组集（202），N相第一绕组集（201）和N相第二绕组集（202）均用于通过转换模块（300）与动力电池（100）连接。当启动对动力电池（100）加热时，对N相第一绕组集（201）和N相第二绕组集（202）进行通电，第一绕组集（201）产生的磁场的方向与第二绕组集（202）产生的磁场具有相位差，磁场相互抵消，每相定子绕组内磁场强度减少，气隙磁通减少，进而减少电机发热以及电机NVH问题。

Description

电机、动力系统、控制方法以及电动汽车 技术领域
本申请涉及电动汽车领域，更具体地，涉及一种电机、动力系统、控制方法以及电动汽车。
背景技术
电动汽车是指由动力电池提供动力的汽车。由于动力电池材料限制，使其在额定电芯温度下才能稳定地发挥出最佳性能，因此，在电芯温度较低地区使用电动汽车时，需要将动力电池加热至额定电芯温度。
现有动力电池加热方式可以分为间接加热和直接加热。间接加热就是指在动力电池外部放置热源进行加热。直接加热是指在动力电池内部对动力电池进行加热。目前业内提出了一种直接加热方式为通过电机对动力电池进行加热。
然而，现有电机在向动力电池提供加热电流时，会出现转子发热严重以及电机NVH问题(NVH全称为：Noise，Vibration，Harshness，中文名称为：噪声、振动以及声振粗糙度)，进而影响电机寿命及降低乘客的舒适度，目前亟需改善电机发热及NVH问题。
发明内容
本申请提供一种电机、动力系统、控制方法以及电动汽车，旨在解决电机工作于为动力电池提供加热电流时，转子发热量大以及电机NVH指标不达标的技术问题。
第一方面，本申请提供一种电机，包括：N相第一绕组集以及N相第二绕组集，其中，N为正整数，电机用于为动力电池加热；
当电机为动力电池加热时，对第一绕组集以及第二绕组集进行通电，使第一绕组集产生的磁场的方向与第二绕组集产生的磁场方向具有相位差，第一绕组集和第二绕组集产生的磁场的总磁通量在预设磁通量阈值范 围内。
根据本实施例的电机，电机的定子绕组包括两组子绕组集，电机用于为动力电池加热时，两组子绕组集均通入电流，使两组子绕组集产生磁场存在相位差，两组子绕组集产生磁场相互抵消，使得定子绕组内磁场强度减少，气隙磁通减少，以减少电机发热和电机NVH问题。
在一些实施例中，第一绕组集和第二绕组集位于同一定子槽内。
根据本实施例，第一绕组集产生的磁场和第二绕组集产生的磁场的方向相反，从而达到减少气隙磁通，减少电机发热和NVH问题。
在一些实施例中，第一绕组集和第二绕组集位于相邻定子槽内。
根据本实施例，第一绕组集产生的磁场和第二绕组集产生的磁场的具有相位差，两个磁场相互部分抵消，从而达到减少气隙磁通的目的。
在一些实施例中，第一绕组集位于定子槽的槽底，第二绕组集位于定子槽的槽口。
在一些实施例中，通入第一绕组集的电流和第二绕组集内的电流相位差值在预设相位阈值内，两者之间的幅值差值在预设幅值阈值内。
根据本实施例，由于第一绕组集产生的磁场和第二绕组集第一绕组集通入的电流具有相位差值在预设相位阈值内，因此产生的磁场和第二绕组集产生的磁场的具有相位差，两者之间的幅值差值在预设幅值阈值内，从而达到减少总气隙磁通的目的。
第二方面，本申请提供一种动力系统，包括：动力电池、转换模块和第一方面及可选方案所涉及的电机；
其中，转换模块的直流侧连接动力电池的正负极，转换模块的第一交流侧与第一绕组集连接，转换模块的第二交流侧与第二绕组集连接。
在一些实施例中，转换模块包括三桥臂的逆变器；
其中，三桥臂的逆变器的直流侧与动力电池的正负极连接，三桥臂的逆变器的交流侧与第一绕组集连接，开关组件连接于三桥臂的逆变器的交流侧和第二绕组集之间。
在一些实施例中，转换模块包括两个三桥臂的逆变器；
其中，两个三桥臂的逆变器的直流侧均与动力电池的正负极连接，一个三桥臂的逆变器的交流侧与第一绕组集连接，另一个三桥臂的逆变器的 交流侧与第二绕组集连接。
在一些实施例中，转换模块包括六桥臂的逆变器，六桥臂的逆变器包括两个交流侧；
其中，六桥臂的逆变器的直流侧与动力电池的正负极连接，六桥臂的逆变器的一个交流侧与第一绕组集连接，六桥臂的逆变器的另一个交流侧和第二绕组集连接。
在一些实施例中，第二绕组集和第一绕组集的中性点连接。
第三方面，本申请提供一种加热控制方法，方法应用于动力系统，动力系统包括电机、逆变器和动力电池，方法执行于电机的控制器，方法包括：
接收动力电池的电芯温度和电机的运行状态信息；
根据电芯温度和运行状态信息判断是否满足加热条件；
若判断结果为是，使动力电池对第一绕组集和第二绕组集中进行通电，使第一绕组集产生的磁场的方向与第二绕组集产生的磁场具有相位差，第一绕组集和第二绕组集产生的磁场的总磁通量在预设磁通量阈值范围内。
在一些实施例中，逆变器包括开关组件；对第一绕组集和第二绕组集中进行通电，具体包括：
向逆变器的开关组件输入脉宽调制信号PWM信号，控制开关组件的通断状态。
第四方面，本申请提供一种电动汽车，包括动力系统，动力系统包括：动力电池、转换模块以及第一方面及可选方案所涉及的电机。
本申请提供一种电机、动力系统、控制方法以及电动汽车，电机通过转换单元与动力电池连接，电机的定子绕组包括两组子绕组集，当动力电池需要加热时，两组子绕组集均通入电流，使两组子绕组集产生磁场存在相位差，两组子绕组集产生磁场相互抵消，使得定子绕组内磁场强度减少，气隙磁通减少，以减少电机发热和电机NVH问题。
附图说明
图1为本申请提供的电动汽车的动力系统的电路原理图；
图2为本申请提供的动力电池的结构示意图；
图3为本申请一实施例提供的电机的结构示意图；
图4为本申请另一实施例提供的电机的结构示意图；
图5为本申请另一实施例提供的动力系统的结构示意图；
图6为本申请另一实施例提供的动力系统的结构示意图；
图7为本申请另一实施例提供的动力系统的结构示意图；
图8为本申请另一实施例提供的动力系统的结构示意图；
图9为本申请另一实施例提供的种动力系统的结构示意图。
具体实施方式
电动汽车是指由动力电池提供动力的汽车。如图1所示，电动汽车的动力系统100包括动力电池10、逆变器20、电机30以及和电机控制器(Motor Controller Unit，简称：MCU)40。动力电池10的正负极与逆变器300的直流侧连接，逆变器20的交流侧与电机30的定子绕组连接。当电动汽车处于行驶状态时，动力电池10通过逆变器20向电机30供电，电机输出动力，驱动汽车行驶。MCU 40设有多个输入端，用于接收电机运行状态数据、以及电机控制指令。MCU40根据电机控制指令、电机运行状态数据以及动力电池的运行状态数据，生成脉宽调制(Pulse Width Modulation，简称：PWM)信号，控制逆变器向电机30提供电压和电流大小，以控制电机转速，以实现汽车行驶速度控制。
如图2所示，动力电池100包括电池模组101、辅助结构102以及电池管理系统103。其中，电池模组101由多个动力电芯串并联而成，动力电芯是动力电池的核心部件，是动力电池提供电能的来源。辅助结构102包括外部框架、固定装置、电连接装置以及绝缘部件。外部框架起到保护、支撑电池模组等作用，电连接装置起到连接其他用电设备的作用，例如：与逆变器连接，绝缘部分起到绝缘保护作用。电池管理系统103主要功能是进行充放电管理、高压控制、评估电池状态、采集电池数据、电池保护以及电池热管理。
电池管理系统103中热管理功能用于确保动力电池工作在适宜温度范围内。电池热管理系统主要功能是电池温度的准确测量和监控，电池组温度过高时进行有效散热，温度过低时，例如低于温度阈值时，进行快速加 热以及保证电池组温度场的均匀分布。其中，由于动力电池材料限制，使其在额定电芯温度下才能稳定地发挥出最佳性能，因此，在电芯温度较低环境地区使用时，需要将动力电池加热至额定电芯温度。
现有动力电池加热方式可以分为间接加热和直接加热。间接加热就是指在动力电池外部放置热源进行加热。间接加热方法可以是空气加热、液体加热以及加热膜加热等。不同的加热源，电池的加热速率也会有所不同。由于是通过外部热源对电池进行加热，在传热介质上将会产生热损耗，因此，间接加热的效率并不高。直接加热是指在内部对动力电池进行加热。目前业内提出了一种直接加热方式为通过电机对动力电池进行加热。
然而，现有通过动力电池内阻进行加热方式，电机在向动力电池提供加热电流时，会出现转子发热严重不能维持加热工况长时间运行以及电机NVH问题。其中，NVH就是Noise，Vibration和Harshness的简称，分别表示噪声、振动以及声振粗糙度。NVH是衡量汽车舒适度的重要指标。
本申请提供一种电机、动力系统、控制方法以及电动汽车，旨在解决上述问题。本申请的发明构思为：在用电机对电池进行直接加热时，改变了电机常规的运行工况，导致该工况下电机气隙的磁通密度分布极度不均匀，从而使转子发热严重，不能维持加热工况长时间运行，同时也产生电机NVH问题。基于上述分析，本申请设置两组定子绕组，在电机向外输出动力时，由两组绕组或者其中任意一组绕组，或者两组绕组同时工作且控制量两组绕组产生的总磁场磁通量大于任意一组绕组产生的磁通量，与转子产生磁场相互作用，以输出动力。在利用电机为动力电池的进行加热时，两组绕组中均通入电流，使两组绕组产生磁场存在相位差，两组绕组产生磁场相互抵消，使得定子绕组内磁场强度减少，气隙磁通减少，以减少电机振动和转子发热。电机振动与气隙的磁通密度和分布不均匀有关，由于气隙磁通密度减少，由磁场分布不均匀引起的电机NVH问题在根源上也得到了一定程度的抑制。
下面描述本申请一实施例提供的电机的结构，本申请提供的电机包括：N相第一子绕组集、N相第二子绕组集、定子铁芯及转子。其中，N为正整数，电机用于为动力电池加热，也可以用于提供动力。
其中，第一子绕组集和第二子绕组集绕于定子铁芯上，绕组可以为集 中式绕组或者分布式绕组，此处不限定。
当电机为动力电池加热时，对第一绕组集以及第二绕组集进行通电，使第一绕组集产生的磁场的方向与第二绕组集产生的磁场方向具有相位差，第一绕组集和所述第二绕组集产生的磁场的总磁通量在预设磁通量阈值范围内。
其中，该预设磁通量阈值范围大于0，小于第一绕组集产生的磁场磁通量和第二绕组集产生的磁场磁通量中的任一值。
当电机为动力电池加热时，使两个子绕组集产生具有相位差的磁场，两个磁场相互抵消，控制总磁场在合理的范围内，使利用电机为动力电池加热的过程中能满足NVH的要求。同时，由于电机本身的设置即可使加热的过程中能满足NVH的要求，所以也能降低对电机控制难度的要求。
下面以分布式绕组为例进行说明，本领域技术人员应该理解，集中式绕组也可以参照该方式实现。
当分布式绕组时，作为一种实现方式，第二绕组集和第一绕组集位于同一个定子槽内，第一绕组集位于定子槽的槽底，第二绕组集位于定子槽的槽口，位于同一定子槽内的绕组布置可以实现不减少电机的输出功率。
作为另一种实现方式，可将第一绕组集和第二绕组集设置于相邻定子槽内，可以不改变定子槽原结构。
第一绕组集和第二绕组集均用于通过转换模块与动力电池连接，以实现电机与动力电池之间电能传输。
电机除了可以为动力电池加热之外，还可以向外输出动力。当电机向外输出动力时，可以仅向第一绕组集中通入交流电，由第一绕组集产生磁场，与转子产生磁场相互作用，向外输出动力。还可以同时向第一绕组集和第二绕组集中通入交流电，由第一绕组集和第二绕组集共同产生磁场。
当电机为动力电池加热时，对第一绕组集和第二绕组集均通电，转子处于堵转状态，固定转子，使得第一绕组集和第二绕组集作为储能元件，向动力电池提供交变电流，实现动力电池利用自身内阻加热。另外，对第一绕组集和第二绕组集均通电，并使第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，定子绕组产生的总磁场趋近于零，气隙磁通密度减少，转子上的磁密也变小。
在一些实施例中，当第二绕组集和第一绕组集位于同一个定子槽内，第一绕组集位于定子槽的槽底，第二绕组集位于定子槽的槽口时，在加热工况下，当向第一绕组集的电流和通入第二绕组集的电流方向相反时，第一绕组集产生的磁场和第二绕组集产生的磁场的方向相反，从而达到减少气隙磁通，减少电机发热和NVH问题。
在一些实施例中，当第一绕组集和第二绕组集设置于相邻定子槽内，在加热工况下，当向第一绕组集的电流和通入第二绕组集的电流时，第一绕组集产生的磁场和第二绕组集产生的磁场的方向具有相位差，控制第一绕组集和第二绕组集产生的总磁通量在预设磁通量阈值范围内，该预设磁通量阈值范围小于第一绕组集和第二绕组集中任一个产生的磁场的磁通量。
其中，通过控制通入第一绕组集和第二绕组集中的电流、第一绕组集和第二绕组集的匝数，使第一绕组集和第二绕组集产生的总磁通量在预设磁通量阈值范围内。其中，预设磁通量阈值是根据转子的最高发热温度和转子的最大振动噪声确定的，通过总磁通量在预设磁通量阈值范围内，从而控制转子发热量和振动噪声在允许范围内。
第一绕组集和第二绕组集的绕线方向可以不同，也可以相同，还可以存在相位差，通过控制第一绕组集和第二绕组集通入的电流相位差值在预设相位阈值内，两者之间的幅值差值在预设幅值阈值内，使第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差和幅值差，两个定子绕组产生的磁场相互抵消，第一绕组集和第二绕组集产生的总磁通量在预设磁通量阈值范围内。
也可以单独控制相位差值、幅值差值和匝数差值任意一项，实现控制磁通量在预设磁通量阈值范围内，该预设磁通量阈值范围大于0，小于第一绕组集产生的磁场磁通量和第二绕组集产生的磁场磁通量中的任一值。
例如：通过控制通入第一绕组集的电流和通入第二绕组集的电流之间的相位差值在预设相位阈值内，并控制通入第一绕组集的电流和通入第二绕组集的电流之间的幅值差值在预设幅值阈值内，达到控制通入第一绕组集和第二绕组集产生的总磁通量在阈值范围内的目的。
例如：通过控制第一绕组集的匝数和第二绕组集的匝数的匝数差值在 预设匝数阈值内，达到第一绕组集和第二绕组集产生的总磁通量在预设磁通量阈值范围内。
第一绕组集和第二绕组集中绕组的绕组匝数可以不同，是与转子发热程度和振动噪声有关的量。其中，具体匝数计算公式如下：
W1:W2＝E φ1:E φ2    (1)
其中，E φ1为第一绕组集的相电势幅值，E φ2为第二绕组集的相电势幅值。
又第一绕组集的相电势幅值和第二绕组集的相电势幅值满足如下公式：
Figure PCTCN2020106473-appb-000001
其中，ω为通电角频率，φ m为气隙磁通密度阈值，该阈值根据允许最大转子发热量和最大振动噪声确定。
通过控制第一绕组集和第二绕组集中绕组的导线线径或绕组匝数，可以将第一绕组集磁场和第二绕组集磁场的合成磁场控制在需要的阈值范围内。例如，通过控制第一绕组集和第二绕组集绕组的导线线径相同、绕组匝数相同，绕制方向相反，可以使上述合成磁场磁通量趋近于零。
在一些实施例中，第一绕组集和第二绕组集采用相同的导线绕制，第一绕组集的匝数与第二绕组集的匝数相同，且绕线方向相反，并使第一绕组集和第二绕组集中所通交流电相位相同，以达到第一绕组集中磁场和第二绕组集中磁场可以完全抵消，气隙的磁通密度趋于零，转子发热量可以趋于零。
下面分析转子发热量降低和振动减少的原理：转子涡流损耗计算公式如下所示：
Figure PCTCN2020106473-appb-000002
其中，P C表示转子涡流损耗，K C为涡流损耗系数，f为电流频率，B S为转子磁通密度幅值。
根据上述公式可知，转子涡流损耗与转子磁通密度的2次方成正比，转子磁通密度的削弱，转子涡流损耗成平方关系下降，即可解决转子温升高的问题，进而解决自加热不能长时间使用的问题。又由于电机振动与气 隙的磁通密度和分布不均匀有关，气隙磁通密度趋向于0，由磁场分布不均匀引起的电机振动噪声的问题得到。
在本申请实施例提供的电机中，当电机工作于加热工况时，使第一绕组集和第二绕组集产生的磁场具有相位差，磁场相互抵消，使得每相定子绕组内磁场强度趋近于零，进而使得气隙磁通减少，以减少电机振动和转子发热，在利用电机对动力电池加热的过程中能满足NVH的要求。通过设置定子绕组通入电流以及绕制方式克服NVH问题，可以进一步降低电机控制难度。
下面结合图3，以三相电机为例描述本申请另一实施例提供的电机的结构。本申请另一实施例提供的电机200包括三相对称第一绕组集201、三相对称第二绕组集202、定子铁芯203及转子。
如图3所示，三相对称第一绕组集201和三相对称第二绕组集202均缠绕于定子铁芯203上，且位于同一定子槽内。其中，第一绕组集和第二绕组集的绕制方向相反，还可以相同，还可以存在相位差。
继续参考图3，第一绕组集201的匝数为a1，分别记作A1、B1、C1；第二绕组集202的匝数为a2，分别记作A2、B2、C2。第一绕组集A1、B1、C1的中性点和第二绕组集A2、B2、C2的中性点不连接。第一绕组集A1、B1、C1和第二绕组集A2、B2、C2分别与转换单元的两个交流侧连接。
三相第一绕组集按照常规绕线方式绕制。下面以第一绕组集和第二绕组集的绕制方向相反为例说明第一绕组集和第二绕组集的绕制方式：将A2相绕组与C1相绕组放在同一个槽内；将C2相绕组与A1相绕组放在同一个槽内；将B2相绕组与B1相绕组放在同一个槽内。第一绕组集沿圆周分布为A1→B1→C1，对应第二绕组集沿圆周分布为C2→B2→A2。这种布线方式，在通同向电流时，第一绕组集和第二绕组集产生相反磁场。
针对第一绕组集和第二绕组集的绕制方向相同或者存在相位差的情况，可以控制流入第一绕组集和第二绕组集中电流相位和幅值，使第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个定子绕组产生的磁场相互抵消。
作为另一种实施例方式，如图4所示，三相对称第一绕组集201和三相对称第二绕组集202位于相邻定子槽。且第一绕组集和第二绕组集的绕制方向相反，还可以相同，还可以存在相位差。可以控制流入第一绕组集和第二绕组集中电流相位和幅值，使第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个定子绕组产生的磁场相互抵消。
当电机为动力电池加热时，对第一绕组集和第二绕组集进行通电，使得第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，使得定子绕组产生的总磁场趋近于零，进而使得气隙磁通密度减少，转子上的磁密也会变得很小。
在本申请实施例提供的电机中，当电机工作于加热工况时，使第一绕组集和第二绕组集产生相反的磁场，磁场相互抵消，使得每相定子绕组内磁场强度趋近于零，进而使得气隙磁通减少，以减少电机振动和转子发热。
下面结合图5，以三相电机为例描述本申请另一实施例提供的动力系统的结构。本申请另一实施例提供的动力系统包括：动力电池100、转换模块300和电机。电机包括三相第一绕组集201和三相第二绕组集202，在图3所示仅示出定子绕组。
其中，转换模块300包括一个直流侧和两个交流侧，转换模块300的直流侧分别连接动力电池100的正负极，转换模块300的其中一个交流侧与第一绕组集201连接，转换模块的另外一个交流侧与第二绕组集202连接。
当电机向外输出动力时，转换模块300工作在逆变器状态，将动力电池输出的直流电转换为交流电，为电机提供交流电激励。当电机为动力电池加热时，转换模块300作为加热回路中一部分，电机的定子绕组作为储能元件向动力电池提供交变电流。
下面描述动力系统的工作原理：当电机向外输出动力时，动力电池通过控制转换模块仅对第一绕组集中进行供电，由第一绕组集产生磁场，与转子产生磁场相互作用，向外输出动力。还可以是对第一绕组集和第二绕组集都通电，由第一绕组集和第二绕组集产生磁场叠加增强，与转子产生磁场作用，向外输出动力。当电机为动力电池加热时，通过控制转换模块 对第一绕组集和第二绕组集中进行通电，并使第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，使得定子绕组产生的总磁场趋近于零，气隙磁通密度减少，转子上的磁密也会变得很小。以减少电机振动和转子发热。
在本申请提供的动力系统中，当电机需要工作于加热工况时，固定转子，其中固定转子包括控制电机转子堵转状态和电机转子处于相对静止状态，即电机转子转动很小，在转动偏差范围内。通过控制转换模块使电机的第一绕组集和第二绕组集均通电，两个定子绕组产生的磁场相互抵消，使得气隙磁通密度减少，转子上的磁密也会变得很小，以减少电机振动和转子发热。
下面结合图6，以三相电机为例描述本申请另一实施例提供的动力系统的结构。本申请另一实施例提供的动力系统包括：动力电池100、转换模块300和电机。电机包括三相第一绕组集201和三相第二绕组集202。
本申请实施例提供的动力系统与图5所示实施例提供的动力系统的区别在于：转换模块300包括三桥臂的逆变器和开关组件。其中，第一桥臂由功率管V1和V4组成，第二桥臂由功率管V2和V5组成，第二桥臂由功率管V3和V6组成。其中，逆变器的直流侧与动力电池100的正负极连接，逆变器的交流侧与第一绕组集201连接，开关组件连接于逆变器的交流侧和第二绕组集202之间，开关组件包括开关S1、开关S2、开关S3。
其中，三相第一绕组集201和三相第二绕组集202的绕向可以相同，还可以相反，还可以存在相位差。通过控制功率管V1至功率管V6的导通和截止状态，控制通入三相第一绕组集201和三相第二绕组集202中电流方向、电流相位以及电流幅值，以使三相第一绕组集201和三相第二绕组集202中产生可以抵消的磁场。
下面描述动力系统的工作原理：
当电机向外输出动力时，可以为断开开关组件，并向逆变器的桥臂控制端输入脉宽调制信号PWM信号，仅对第一绕组集中进行通电，由第一绕组集产生磁场，与转子产生磁场相互作用，向外输出动力。
当电机向外输出动力时，还可以是闭合开关组件，并向逆变器的桥臂 控制端输入PWM信号，对第一绕组集和第二绕组集中绕组均通电，使得第一绕组集和第二绕组集中磁场方向相同，使得第一绕组集和第二绕组集的磁场叠加增强。以实现由第一绕组集和第二绕组集共同产生增强磁场，与转子产生磁场相互作用，向外输出动力。
当电机向外输出动力时，还可以是闭合开关组件，并向逆变器的桥臂控制端输入PWM信号，对第一绕组集和第二绕组集中绕组均通电，使第一绕组集和第二绕组集中磁场存在相位，并且第一绕组集和第二绕组集的总磁场大于第一绕组集产生磁场，或者大于第二绕组集产生磁场。也就是第一绕组集和第二绕组集的总磁场是叠加增强的。以实现由第一绕组集和第二绕组集共同产生增强磁场，与转子产生磁场相互作用，向外输出动力。
当电机为动力电池加热时，闭合开关组件，并向逆变器的桥臂控制端输入脉宽调制信号PWM信号，对第一绕组集和第二绕组集中进行通电，第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，定子绕组产生的总磁场趋近于零，气隙磁通密度减少，转子上的磁密也会变得很小，电机振动和转子发热也相应地降低。
需要说明的是，此处不限定桥臂控制端的控制信号为PWM信号，也可以为其他能够控制桥臂信号。
通过三桥臂的逆变器和开关组件配合控制通入绕组中电流相位和电流大小，仅需向逆变器输入三路控制信号，可以降低控制难度。
当电机为动力电池加热时，以第一绕组集和第二绕组集绕制方向相反，PWM信号使功率管V1、V5和V6导通和断开，且开关组件S1、S2、S3闭合为例，描述电机中第一绕组集和第二绕组集作为储能元件向电池充电过程。
针对第一绕组集：控制A1相桥臂上的功率管V1，B1相桥臂上的功率管V5和C1相桥壁上的功率管V6导通，功率管V2、V3、V4断开。此时形成如下放电回路：动力电池→功率管V1→A1相定子电感→B1相定子电感→功率管V5→动力电池，以及动力电池→功率管V1→A1相定子电感→C1相定子电感→功率管V6→动力电池。在这个过程中，动力电池放电并将电能转化A相、B相和C相定子电感上的电磁能，定子电感储能。回路中加热电流的大小由功率管V1、V5和V6的闭合时间决定，也就是由 驱动功率管V1、V5和V6信号的频率f和占空比D确定。在下一个时间(即闭合时间结束)，同时断开功率管V1、V5和V6，由于电感中电流不能突变的特点，此时，形成如下动力电池的充电回路：C1相定子电感→晶体二极管D3→动力电池→晶体二极管D4→A1相定子电感，以及B1相定子电感→晶体二极管D2→动力电池→晶体二极管D4→A1相定子电感。在上述对动力电池放电和充电过程中，都有电流流过动力电池，实现对动力电池加热，此时定子第一绕组集将产生一个方向不变，幅值交变的定子主磁场，交变频率即为PWM信号的周期。
针对第二绕组集：功率管V1、V5以及V6导通，开关S1、开关S2、开关S3导通，此时第二绕组集的辅通电回路与第一绕组集类似：动力电池→功率管V1→开关S1→A2相定子电感→B2相定子电感→开关S2→功率管V5→动力电池，以及动力电池→功率管V1→开关S1→A2相定子电感→C2相定子电感→开关S3→功率管V6→动力电池，在这个过程中，动力电池放电并将电能转化成A相、B相和C相定子电感上的电磁能，定子电感储能，回路中加热电流的大小由功率管V1、V5和V6的闭合时间决定，也就是由驱动V1、V5和V6信号的频率f和占空比D确定。在下一个时间，同时断开功率管V1、V5和V6，由于电感中电流不能突变的特点，此时，形成如下动力电池的辅助充电回路：C2相定子电感→功率管S3→晶体二极管D3→动力电池→晶体二极管D4→开关S1→A2相定子电感，以及B2相定子电感→开关S2→晶体二极管D2→动力电池→晶体二极管D4→开关S1→A1相定子电感。
在上述第二绕组集通过电流时，由于第二绕组集的绕组方向和第二子绕组集的绕组方向相反，将会产生一个与第一绕组集磁场方向相反，幅值变化与第一绕组集产生磁场幅值变化一致的磁场。此时，第一绕组集磁场和第二绕组集磁场的合成磁场将会明显减小。通过控制第一绕组集和第二绕组集绕组的导线线径或绕组匝数，可以将第一绕组集磁场和第二绕组集磁场的合成磁场控制在需要的阈值范围内。例如，通过控制第一绕组集和第二绕组集绕组的导线线径相同、绕组匝数相同，绕制方向相反，可以使上述合成磁场磁通量趋近于零。
在本申请提供的动力系统中，当电机需要工作于加热工况时，通过闭 合开关组件，并控制逆变器的桥臂控制端，使电机的第一绕组集和第二绕组集均通电，两个定子绕组产生的磁场相互抵消，使得气隙磁通密度减少，转子上的磁密也会变得很小，以减少电机振动和转子发热。
下面结合图7，以三相电机为例描述本申请另一实施例提供的动力系统的结构。本申请另一实施例提供的动力系统包括：动力电池100、转换模块300和电机。电机包括三相第一绕组集201和三相第二绕组集202。
本申请另一实施例提供的动力系统与图5所示实施例提供的动力系统的区别在于：转换模块300包括两个三桥臂的逆变器301。其中，两个逆变器301的直流侧均与动力电池100的正负极连接，一个逆变器301的交流侧与第一绕组集201连接，另一个逆变器301的交流侧与第二绕组集202连接。
其中，第二绕组集201和第二绕组集202的绕线方式已经在图5所示实施例中详细说明，此处不再赘述。
下面描述动力系统的工作原理：当电机向外输出动力时，与第一绕组集连接的逆变器的桥臂控制端输入脉宽调制信号PWM信号，仅对第一绕组集中进行通电，由第一绕组集产生磁场，与转子产生磁场相互作用，向外输出动力。还可以使第一绕组集和第二绕组集都通电，由第一绕组集和第二绕组集共同产生磁场。此处已经在图6所示实施例中详细说明，此处不再赘述。
当电机为动力电池加热时，向两个逆变器的桥臂控制端输入脉宽调制信号PWM信号，对第一绕组集和第二绕组集中进行通电，第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，定子绕组产生的总磁场趋近于零，气隙磁通密度减少，转子上的磁密也会变得很小，电机振动和转子发热也相应地降低。
通过两个三桥臂的逆变器配合控制通入绕组中电流相位和电流大小，可实现全部由开关控制，进而提高控制可靠度。
在本申请提供的动力系统中，为第一绕组集和第二绕组集分别设有逆变器，当电机需要工作于加热工况时，通过控制两个逆变器的桥臂控制端，使电机的第一绕组集和第二绕组集均通电，以减少电机振动和转子发热。
下面结合图8，以三相电机为例描述本申请另一实施例提供的动力系统的结构。本申请另一实施例提供的动力系统包括：动力电池100、转换模块300和电机。电机包括三相第一绕组集201和三相第二绕组集202。
本申请另一实施例提供的动力系统与另一实施例提供的动力系统的区别在于：转换模块300包括一个六桥臂的逆变器，前三个桥臂的中点构成逆变器的一个交流侧，后三个桥臂的中点构成逆变器的另一个交流侧。其中，逆变器的直流侧与动力电池100的正负极连接，逆变器的一个交流侧与第一绕组集201连接，逆变器的另一个交流侧与第二绕组集302连接。其中，第二绕组集和第一绕组集的中性点可以相互连接，如图8所示。
其中，第二绕组集201和第二绕组集202的绕线方式已经在图5所示实施例中详细说明，此处不再赘述。
下面描述动力系统的工作原理：当电机向外输出动力时，与第一绕组集连接的桥臂的控制端输入脉宽调制信号PWM信号，仅对第一绕组集中进行通电，由第一绕组集产生磁场，与转子产生磁场相互作用，向外输出动力。或者对第一绕组集和第二绕集均进行通断，且使第一绕组集和第二绕集产生的磁场叠加。此处已经在图6所示实施例中详细说明，此处不再赘述。
当电机为动力电池加热时，向所有桥臂的控制端输入脉宽调制信号PWM信号，对第一绕组集和第二绕组集中进行通电，第一绕组集产生的磁场与第二绕组集产生的磁场的具有相位差，两个子绕组产生的磁场相互抵消，定子绕组产生的总磁场趋近于零，气隙磁通密度减少，转子上的磁密也会变得很小，电机振动和转子发热也相应地降低。
通过六桥臂的逆变器控制通入绕组中电流相位和电流大小，可实现全部由开关控制，进而提高控制可靠度。
在本申请提供的动力系统中，逆变器有六个桥臂，三个桥臂的中点与第一绕组集连接，另外三个桥臂的中点与第二绕组集连接。当电机需要工作于加热工况时，通过控制所有桥臂控制端，使电机的第一绕组集和第二绕组集均通电，以减少电机振动和转子发热。
本领域技术人员应当理解，两个三相桥臂和六相桥臂的情况下均可以通 过控制绕组的相位差，开关的布置和通断，以控制第一绕组集和第二绕组集的电流的相位差，电流的幅值，达到使第一绕组集和第二绕组集的合成磁场在预设磁通范围。
本申请另一实施例还提供一种电动汽车，包括上述实施例提供的动力系统。具体可以参见前述动力系统实施例中的相关描述。
下面结合上述实施例描述的电机和动力系统，描述本申请实施例提供的加热控制方法。其中，加热控制方法包括：
S401、获取动力电池的电芯温度和电机的运行状态信息。
其中，根据安装在动力电池内部的温度传感器，随时监测电芯温度。
在一些实施例中，动力电池包括电池管理系统，电池管理系统获取电动力电池温度，并将电池温度信息发送给电机控制器，其中，电机包括电机控制器。电机控制器接收电池的温度信息。
在一些实施例中，电机控制器还接收电机的运行状态信息，电机的运行状态信息包括，电机定子的温度、电机定子绕组的温度、电机处于为动力电池加热的工况、电机处于向外输出动力的工况、电机处于堵转状态和/或电机处于停止工作状态，在此不作具体限定。
S402、判断电芯温度和运行状态是否满足动力电池加热条件，若是，进入S403，否则，进入S404或者使电机处于停止工作状态。
在一些实施例中，动力电池加热条件包括电芯温度小于预设温度阈值，且电机转子运行状态为堵转状态。其中，预设温度阈值根据动力电池的额定工作温度确定。
在一些实施例中，加热条件包括动力电池的电芯温度小于预设温度阈值，和电机的运行状态为停止工作状态。
在一些实施例中，加热条件包括动力电池的电芯温度小于预设温度阈值，电机的运行状态为堵转状态，和电机定子的温度、电机定子绕组的温度低于预设电机温度阈值，预设电机温度阈值根据动力电池的额定工作温度确定。
本领域技术人员应当理解，可以根据需要设置加热条件，在此不作限定。
S403、向第一绕组集和第二绕组集中通入交变电流，并使第一绕组集 产生的磁场与第二绕组集产生的磁场具有相位差，第一绕组集和第二绕组集产生的总磁通量在预设磁通量阈值范围内。
其中，预设磁通量阈值范围小于第一绕组集产生的总磁通量，预设磁通量阈值范围同时也小于第一绕组集产生的总磁通量，也就是使第一绕组集产生的磁场与第二绕组集产生的磁场相互抵消，使第一绕组集产生的磁场与第二绕组集产生的磁场的总磁场减少，气隙磁密减少，发热量减少，振动也相应减少。
不同的动力系统结构，实现方式不同。当转换模块包括一个三桥臂的转换模块和开关组件，且第一绕组集和第二绕组集绕组方向相反时，闭合开关组件，并向转换模块的桥臂控制端输入PWM信号，以实现向第一绕组集和第二绕组集中通入交变电流，并保证第一绕组集产生的磁场的方向与第二绕组集产生的磁场具有相位差。
当转换模块包括两个三桥臂的逆变器时，向两个转换模块的所有桥臂控制端均输入PWM信号，两个逆变器控制端输入的PWM信号不同，使第一绕组集产生的磁场的方向与第二绕组集产生的磁场具有相位差。
当转换模块包括一个六桥臂的逆变器时，向转换模块的六个桥臂控制端输入脉宽调制信号PWM信号，其中三个桥臂的PWM信号与另外三个桥臂的PWM信号不同，使第一绕组集产生的磁场的方向与第二绕组集产生的磁场具有相位差。
S404、向第一绕组集或者第二绕组集中通入电流，或者，向第一绕组集和第二绕组集中通入交变电流，第一绕组集和第二绕组集产生的总磁通量大于预设磁通量阈值范围内。
其中，当不满足动力电池加热条件时，仅向第一绕组集或者第二绕组集通电，第一绕组集和第二绕组集产生的总磁通量大于预设磁通量阈值范围内，使第一绕组集产生的磁场与第二绕组集产生的磁场叠加增强，第一绕组集产生的磁场与第二绕组集产生的磁场共同与转子作用，由于磁场加强，电机输出功率大，可以向外提供动力。
本领域技术人员应当理解，第一绕组集和第二绕组集绕组绕制方向相同或者有相位差时，均可以通过控制开关的布置和通断，以控制第一绕组集和第二绕组集的电流的相位差，电流的幅值，达到使第一绕组集和第二绕组集 的合成磁场在预设磁通范围。
在本申请提供的动力系统中，检测到满足动力电池加热条件时，通过控制转换单元，使电机的第一绕组集和第二绕组集均通电，通过控制第一绕组集和第二绕组集合成的磁场的磁通量在预设磁通量阈值范围内，以减少电机振动和转子发热。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (13)

  1. 一种电机，其特征在于，包括：N相第一绕组集以及N相第二绕组集，其中，N为正整数，所述电机用于为动力电池加热；
    当所述电机为动力电池加热时，对所述第一绕组集以及所述第二绕组集进行通电，使所述第一绕组集产生的磁场的方向与所述第二绕组集产生的磁场方向具有相位差，所述第一绕组集和所述第二绕组集产生的磁场的总磁通量在预设磁通量阈值范围内。
  2. 根据权利要求1所述的电机，其特征在于，所述第一绕组集和所述第二绕组集位于同一定子槽内。
  3. 根据权利要求1所述的电机，其特征在于，所述第一绕组集和所述第二绕组集位于相邻定子槽内。
  4. 根据权利要求2所述的电机，其特征在于，所述第一绕组集位于所述定子槽的槽底，所述第二绕组集位于所述定子槽的槽口。
  5. 根据权利要求1至4任一项所述的电机，其特征在于，通入所述第一绕组集的电流和第二绕组集内的电流相位差值在预设相位阈值内，两者之间的幅值差值在预设幅值阈值内。
  6. 一种动力系统，其特征在于，包括：动力电池、转换模块和如权利要求1至5任一项所述的电机；
    其中，所述转换模块的直流侧连接所述动力电池的正负极，所述转换模块的第一交流侧与所述第一绕组集连接，所述转换模块的第二交流侧与所述第二绕组集连接。
  7. 根据权利要求6所述的动力系统，其特征在于，所述转换模块包括三桥臂的逆变器；
    其中，所述三桥臂的逆变器的直流侧与所述动力电池的正负极连接，所述三桥臂的逆变器的交流侧与所述第一绕组集连接，开关组件连接于所述三桥臂的逆变器的交流侧和所述第二绕组集之间。
  8. 根据权利要求6所述的动力系统，其特征在于，所述转换模块包括两个三桥臂的逆变器；
    其中，两个三桥臂的逆变器的直流侧均与所述动力电池的正负极连接，一个三桥臂的逆变器的交流侧与所述第一绕组集连接，另一个三桥臂的逆 变器的交流侧与所述第二绕组集连接。
  9. 根据权利要求6所述的动力系统，其特征在于，所述转换模块包括六桥臂的逆变器，所述六桥臂的逆变器包括两个交流侧；
    其中，所述六桥臂的逆变器的直流侧与所述动力电池的正负极连接，所述六桥臂的逆变器的一个交流侧与所述第一绕组集连接，所述六桥臂的逆变器的另一个交流侧和所述第二绕组集连接。
  10. 根据权利要求6至9中任意一项所述的动力系统，其特征在于，所述第二绕组集和所述第一绕组集的中性点连接。
  11. 一种加热控制方法，其特征在于，所述方法应用于动力系统，所述动力系统包括电机、逆变器和动力电池，所述方法执行于所述电机的控制器，所述方法包括：
    接收所述动力电池的电芯温度和所述电机的运行状态信息；
    根据所述电芯温度和所述运行状态信息判断是否满足加热条件；
    若判断结果为是，使所述动力电池对第一绕组集和第二绕组集中进行通电，使所述第一绕组集产生的磁场的方向与所述第二绕组集产生的磁场具有相位差，所述第一绕组集和所述第二绕组集产生的磁场的总磁通量在预设磁通量阈值范围内。
  12. 根据权利要求11所述的方法，其特征在于，所述逆变器包括开关组件；对第一绕组集和第二绕组集中进行通电，具体包括：
    向所述逆变器的开关组件输入脉宽调制PWM信号，控制所述开关组件的通断状态。
  13. 一种电动汽车，其特征在于，包括动力系统，所述动力系统包括：动力电池、转换模块以及如权利要求1至5任一项所述的电机。
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