Motor and system

Abstract

The invention discloses a motor, a motor controller, a heat exchange system and a control method, relates to the field of motors, and aims to improve the heating efficiency of the motor. The motor comprises a shell, a stator mounted in the shell, a rotor connected with the shell through a bearing, a winding wound on the stator, and a liquid inlet hole and a liquid outlet hole which are communicated with a cavity in the shell; the liquid inlet hole is used for inflow of insulating cooling liquid, and the liquid outlet hole is used for outflow of the insulating cooling liquid; the rotor comprises a rotating shaft, a rotor iron core installed around the rotating shaft and a permanent magnet installed on the rotor iron core. The rotor iron core is provided with a first hole channel communicated with the cavity; the winding is used for inputting direct-axis alternating current.

Description

[0001] This application is a divisional application. The application number of the original application is 202080009778.2, and the original application date is October 23, 2020. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of motors, and in particular to a motor, a motor controller, a heat exchange system and a control method. Background Art

[0003] With the development of new energy vehicle technology and the growing market, electric vehicles are becoming more and more popular among consumers. However, the batteries of electric vehicles are currently suitable for working in a certain temperature range. When the temperature is too low, the battery performance will be greatly affected. Take lithium batteries as an example:

[0004] (1) The activity of the positive electrode material of the battery decreases, the number of lithium ions moving inside the battery decreases, and the battery capacity decreases.

[0005] (2) The electrolyte solidifies, causing the diffusion and movement of charged ions in the positive and negative electrode materials of the battery to deteriorate, the speed of electrical energy transfer to decrease, and the battery discharge rate to decrease.

[0006] (3) The lattice of the negative electrode material shrinks, making it difficult for lithium ions to embed, and the charging speed decreases.

[0007] Therefore, the battery needs to be heated in a low temperature environment to avoid the above problems. Currently, one way to heat the battery is to connect direct current to the winding of the motor stator and use the copper loss of the winding to generate heat to heat the battery. However, this method has a small heating power and a slow heating speed because the winding is small. Summary of the invention

[0008] Embodiments of the present application provide a motor, a motor controller, a heat exchange system and a control method for improving the efficiency of motor heating.

[0009] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0010] In a first aspect, a motor is provided, comprising a housing, a stator installed inside the housing, a rotor connected to the housing through a bearing, a winding wound on the stator, and a liquid inlet and a liquid outlet connected to a cavity in the housing; the liquid inlet is used for the inflow of insulating coolant, and the liquid outlet is used for the outflow of insulating coolant; the rotor comprises a rotating shaft, a rotor core installed around the rotating shaft, and a permanent magnet installed on the rotor core; the rotor core is provided with a first channel connected to the cavity; the winding is used for inputting direct-axis alternating current.

[0011] The motor provided in the embodiment of the present application inputs cross-axis alternating current into the windings of the motor, so that the rotating shaft, rotor core and stator of the motor rotor are heated due to eddy current loss and hysteresis loss, the permanent magnets of the rotor are heated due to eddy current loss, and the windings are heated due to copper loss. Therefore, compared with heating that relies solely on copper loss in the windings, higher heating power and heating efficiency can be provided, and the heating speed can be accelerated.

[0012] In a possible implementation, a second channel communicating with the cavity is provided in the rotating shaft, and the insulating coolant flowing in the second channel performs heat exchange with the rotating shaft.

[0013] In a possible implementation, the liquid inlet hole includes a first liquid inlet hole, which is disposed on the rotating shaft and communicates with the second hole, so that the insulating coolant can flow into the motor through the rotating shaft.

[0014] In a possible implementation, a third hole is further provided between the rotating shaft and the rotor core, and the first hole is connected to the second hole through the third hole. The third hole is used to connect the first hole with the second hole, thereby facilitating the flow of insulating coolant inside the motor.

[0015] In a possible implementation manner, a fourth hole communicating with the cavity is provided on the stator, and the insulating coolant flowing in the fourth hole is used for heat exchange with the stator.

[0016] In a possible implementation, the liquid inlet hole includes a second liquid inlet hole, and the second liquid inlet hole is arranged at a position on the top of the shell opposite to the winding, so that the insulating coolant flowing in from the second liquid inlet hole flows onto the winding under the action of gravity, thereby performing heat exchange with the winding.

[0017] In a possible implementation, the liquid outlet is arranged at the bottom of the housing, so that the insulating coolant flows out of the motor from the liquid outlet under the action of gravity.

[0018] In a second aspect, a motor controller is provided, comprising: an inverter circuit and a control device, wherein the control device is used to control the inverter circuit to output direct-axis alternating current to the winding of the motor as described in the first aspect and any embodiment thereof.

[0019] The motor controller provided in the embodiment of the present application inputs cross-axis alternating current into the windings of the motor, causing the rotating shaft, rotor core and stator of the motor rotor to generate heat due to eddy current loss and hysteresis loss, the permanent magnets of the rotor to generate heat due to eddy current loss, and the windings to generate heat due to copper loss. Therefore, compared with heat generation solely relying on copper loss in the windings, higher heating power and heating efficiency can be provided, and the heating speed can be accelerated.

[0020] In a possible implementation, the control device is further configured to: when the battery temperature is lower than the battery temperature threshold, adjust the frequency of the direct-axis AC power according to whether the battery is connected to an external charging power source and the output voltage of the battery. This implementation provides a way to adjust the frequency of the direct-axis AC power.

[0021] In a possible implementation, the control device is specifically used to: when the temperature of the battery is less than the battery temperature threshold, if the battery is connected to an external charging power supply, or if the battery is not connected to an external charging power supply and the output voltage of the battery is greater than a first voltage threshold, then adjust the frequency of the direct-axis alternating current to a first frequency; if the battery is not connected to an external charging power supply and the output voltage of the battery is less than or equal to the first voltage threshold and greater than a second voltage threshold, then adjust the frequency of the direct-axis alternating current to a second frequency; wherein the first voltage threshold is greater than the second voltage threshold, and the first frequency is greater than the second frequency. This implementation provides a specific way of adjusting the frequency of the direct-axis alternating current.

[0022] In a possible implementation, the control device is further used to: when the temperature of the battery is less than the battery temperature threshold, determine the temperature of the rotor of the motor according to at least one of the temperature of the motor housing, the temperature of the winding, the temperature of the insulating coolant flowing out of the motor, and the ambient temperature; and adjust the current intensity of the direct-axis alternating current according to the temperature of the rotor. This implementation provides a way to adjust the current intensity of the direct-axis alternating current.

[0023] In a possible implementation, the control device is specifically used to: when the temperature of the battery is lower than the battery temperature threshold, if the temperature of the rotor is higher than the first rotor temperature threshold, adjust the current intensity of the direct-axis alternating current to the first current intensity; if the temperature of the rotor is lower than the second rotor temperature threshold, adjust the current intensity of the direct-axis alternating current to the second current intensity; otherwise, maintain the current intensity of the direct-axis alternating current; wherein the first rotor temperature threshold is higher than the second rotor temperature threshold, and the first current intensity is lower than the second current intensity. This implementation provides a specific way of adjusting the current intensity of the direct-axis alternating current.

[0024] In a possible implementation, the control device is further configured to: if the temperature of the rotor is greater than a first rotor temperature threshold, adjust the frequency of the direct-axis alternating current to a second frequency. The frequency of the direct-axis alternating current can also be adjusted according to the temperature of the rotor.

[0025] In a possible implementation manner, the control device is further used to: control the inverter circuit to output quadrature-axis current to the winding, so that the motor can be heated while the motor is driven to rotate.

[0026] In a third aspect, a heat exchange system is provided, comprising a motor as in the first aspect and any embodiment thereof, a motor controller as in the second aspect and any embodiment thereof, a heat exchanger and a liquid pump; the liquid pump, the heat exchanger and the liquid outlet and liquid inlet of the motor are connected for the flow of insulating coolant; the motor controller is used for outputting direct-axis alternating current to the windings of the motor and controlling the operation of the liquid pump.

[0027] In a fourth aspect, a control method is provided, comprising: controlling an inverter circuit to output direct-axis alternating current to a winding of a motor as described in the first aspect and any embodiment thereof.

[0028] In a possible implementation, the method further includes: when the temperature of the battery is lower than a battery temperature threshold, adjusting the frequency of the direct-axis alternating current according to whether the battery is connected to an external charging power source or the output voltage of the battery.

[0029] In a possible implementation, when the temperature of the battery is lower than a battery temperature threshold, the frequency of the direct-axis alternating current is adjusted according to whether the battery is connected to an external charging power supply and the output voltage of the battery, including: when the temperature of the battery is lower than the battery temperature threshold, if the battery is connected to an external charging power supply, or if the battery is not connected to an external charging power supply and the output voltage of the battery is greater than a first voltage threshold, the frequency of the direct-axis alternating current is adjusted to a first frequency; if the battery is not connected to an external charging power supply and the output voltage of the battery is less than or equal to the first voltage threshold and greater than a second voltage threshold, the frequency of the direct-axis alternating current is adjusted to a second frequency; wherein the first voltage threshold is greater than the second voltage threshold, and the first frequency is greater than the second frequency.

[0030] In a possible implementation, the method further includes: when the temperature of the battery is lower than the battery temperature threshold, determining the temperature of the rotor of the motor based on at least one of the temperature of the motor housing, the temperature of the winding, the temperature of the insulating coolant flowing out of the motor, and the ambient temperature; and adjusting the current intensity of the direct-axis alternating current based on the temperature of the rotor.

[0031] In one possible implementation, when the temperature of the battery is lower than the battery temperature threshold, the current intensity of the direct-axis alternating current is adjusted according to the temperature of the rotor, including: when the temperature of the battery is lower than the battery temperature threshold, if the temperature of the rotor is higher than the first rotor temperature threshold, the current intensity of the direct-axis alternating current is adjusted to the first current intensity; if the temperature of the rotor is lower than the second rotor temperature threshold, the current intensity of the direct-axis alternating current is adjusted to the second current intensity; otherwise, the current intensity of the direct-axis alternating current is maintained; wherein the first rotor temperature threshold is higher than the second rotor temperature threshold, and the first current intensity is lower than the second current intensity.

[0032] In a possible implementation manner, the method further includes: if the temperature of the rotor is greater than a first rotor temperature threshold, adjusting the frequency of the direct-axis alternating current to a second frequency.

[0033] In a possible implementation manner, the method further includes: controlling the inverter circuit to output quadrature-axis current to the winding.

[0034] In a fifth aspect, a computer-readable storage medium is provided, in which a computer program is stored. When the computer-readable storage medium is run on a computer or a processor, the computer or the processor executes the method described in the fourth aspect and any one of its embodiments.

[0035] In a sixth aspect, a computer program product comprising instructions is provided, which, when the instructions are executed on a computer or a processor, enables the computer or the processor to execute the method described in the fourth aspect and any one of the embodiments.

[0036] The technical effects of the third to sixth aspects refer to the contents of the first to second aspects and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of a direct axis and a cross axis provided in an embodiment of the present application;

[0038] Figure 2 A schematic diagram of a direct-axis alternating current value Id that alternately changes between positive and negative provided in an embodiment of the present application;

[0039] Figure 3 A schematic diagram of the architecture of a heat exchange system provided in an embodiment of the present application;

[0040] Figure 4 A schematic diagram of a process of heating a battery by a motor provided in an embodiment of the present application;

[0041] Figure 5 A schematic diagram of the structure of a motor provided in an embodiment of the present application;

[0042] Figure 6 A schematic diagram of the structure of a rotor of a motor provided in an embodiment of the present application;

[0043] Figure 7 A schematic diagram of a control method provided in an embodiment of the present application Figure 1 ;

[0044] Figure 8 A schematic diagram of a control method provided in an embodiment of the present application Figure 2 ;

[0045] Fig. 9 A schematic diagram of a control method provided in an embodiment of the present application Figure 3 ;

[0046] Fig.10 A schematic diagram of a control method provided in an embodiment of the present application Figure 4 ;

[0047] Fig.11 A schematic diagram of the relationship between the current intensity and frequency of direct-axis alternating current, in which a coordinate system is established using the temperature of the rotor and the output voltage of the battery, is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] First, the concepts involved in the embodiments of the present application are described.

[0049] The motor involved in the embodiments of the present application may be a permanent magnet motor, an asynchronous motor, an excitation motor, a synchronous reluctance motor, etc.

[0050] U / V / W three-phase coordinate axes: Currently, the motors of electric vehicles are generally AC motors, and the batteries are DC sources. Therefore, the DC power output by the battery is converted into three-phase AC power for the motor through an inverter. The coordinate axes of these three-phase AC power are the U axis, V axis, and W axis respectively.

[0051] The direct axis, also known as the D axis or d-axis, is a time-varying DC coordinate axis obtained by Park Transformation of the stationary U / V / W three-phase coordinate axes.

[0052] The quadrature axis, also known as the Q axis or q-axis, is a time-varying AC coordinate axis obtained by Park transformation of the stationary U / V / W three-phase coordinate axes.

[0053] like Figure 1 As shown, the direct axis is perpendicular to the quadrature axis, and the angle θ between the direct axis and the U axis is time-varying, satisfying θ=ωt, where ω is the electrical frequency and t is time.

[0054] Parker transformation converts the analysis method of U / V / W three-phase AC motor into the analysis method of direct axis and quadrature axis of DC motor, which facilitates the electromagnetic field decoupling control of three-phase AC motor.

[0055] Winding: A coil wound around the stator teeth of a motor to provide a path for current. The part that extends out of the rotor core at both ends of the motor shaft is called the end winding. The material of the winding is generally copper.

[0056] Copper loss: The loss caused by current flowing in copper conductors.

[0057] Loss of rotor core: Loss of rotor core in alternating magnetic field, including eddy current loss caused by induced eddy current and hysteresis loss caused by hysteresis effect. Similarly, the rotor shaft and stator will also generate eddy current loss and hysteresis loss in alternating magnetic field. The above losses will cause heat, but the heat of rotor shaft and stator is smaller, while the heat of rotor core is larger.

[0058] Eddy current loss of permanent magnet: Permanent magnet generates eddy current in the alternating magnetic field, which in turn causes corresponding eddy current loss.

[0059] Pulsating magnetic field: a magnetic field whose position is fixed in space and only the amplitude of the magnetic field intensity changes alternately with time.

[0060] At present, there are many ways to heat batteries in the electric vehicle field. The first way to heat batteries is to connect direct current to the windings of the motor stator, causing the windings to heat up due to copper loss. The coolant transfers the heat of the motor to the heat exchanger, which heats the battery. This method has the following disadvantages:

[0061] (1) Only the copper loss of the motor winding is used to generate heat. Since the winding resistance in the motor is small, the heat generation power is also small and the heating speed is slow.

[0062] (2) Only the windings in the motor are heated, while other parts of the motor do not participate in the heating. Therefore, the motor heats up unevenly, which may cause local overheating of the windings and affect the life of the windings.

[0063] (3) The winding temperature rises very quickly and triggers overheating protection when it reaches a certain temperature, so the heating duration is very short.

[0064] (4) Since the motor is an AC motor, it cannot operate when DC power is connected. Therefore, the battery cannot be heated when the motor is operating (for example, when the vehicle is driving).

[0065] The second battery heating method is to lead the three-phase winding of the motor out of the neutral point and connect it to an energy storage device. In the heating mode, the battery charges the motor winding and energy storage device through the inverter, and then the motor winding and energy storage device discharge to the battery through the same circuit, and these two processes are performed alternately. The current in the above process flows through the three-phase winding and then through the neutral point to flow through the energy storage device, so it is a zero-sequence current, that is, the current waveform and phase flowing through the three-phase winding are the same. This technology also uses the copper loss of the winding to generate heat.

[0066] In this method, the neutral point of the motor winding needs to be connected to the energy storage device, which increases the equipment cost. Only the copper loss of the winding is used to generate heat, the heat generation power is small, and the heating speed is slow. In addition, this method conflicts with the normal operation of the motor and cannot heat the battery during the operation of the motor (such as vehicle driving).

[0067] The third battery heating method is to heat the battery through an external heater. However, this method will increase the battery heater and increase the equipment cost.

[0068] The fourth battery heating method is to heat the battery through an external heating film, which is made of a variety of high-temperature resistant organic materials, polymer materials, carbon and high-temperature resistant fibers. Similarly, since the heating film material is expensive, its cost is much higher than that of the heater, and an additional control circuit is required, which increases the equipment cost.

[0069] The embodiment of the present application provides a battery heating method, by inputting direct-axis alternating current into the winding, such as Figure 2 As shown, the current value Id of the direct-axis alternating current changes alternately between positive and negative, rather than the currently commonly used direct-axis direct current, so that the winding generates a magnetic field, the direction of which remains unchanged, and only the amplitude changes alternately between positive and negative, which is a pulsating magnetic field.

[0070] This magnetic field will cause the motor rotor shaft, rotor core and stator to heat up due to eddy current loss and hysteresis loss, the rotor permanent magnets to heat up due to eddy current loss, and the windings to heat up due to copper loss. Therefore, compared with heating simply relying on copper loss in the windings, the method provided in the embodiments of the present application can provide higher heating power and accelerate the heating speed.

[0071] In addition, the battery heating method provided in the embodiment of the present application does not require the addition of other devices and will not increase additional costs. The winding, stator, and the rotating shaft of the rotor, the rotor core, and the permanent magnet are all heated to prevent the motor from being damaged by uneven heating, and the heat source is dispersed to make the motor heat more evenly. Under the same heating power, the heating can be more durable, or in other words, under the same overheating protection limit, a greater heating power can be achieved. Moreover, during the normal operation of the motor, a quadrature-axis current is input to the motor to drive the rotor of the motor to rotate, and a direct-axis alternating current is input to heat the motor, thereby achieving heating of the battery during the operation of the motor (such as vehicle driving).

[0072] like Figure 3 As shown, it is a schematic diagram of a heat exchange system provided in an embodiment of the present application. The heat exchange system includes: a battery 31, a motor controller 32, a motor 33, a heat exchanger 34 and a liquid pump 35. The battery 31 is coupled to the motor controller 32 through a high-voltage DC bus, the motor controller 32 is coupled to the motor 33 through a three-phase line, the motor 33, the heat exchanger 34 and the liquid pump 35 are coupled through a pipeline, and an insulating coolant flows in the pipeline. The insulating coolant may include mineral insulating oil, synthetic insulating oil, vegetable oil, etc.

[0073] The battery 31 is used to output direct current, and includes, for example, a storage battery, a lithium battery, a fuel cell, a super capacitor, etc.

[0074] The motor controller 32 is also called a motor control unit (MCU), and includes a control device 321 and an inverter circuit 322. The control device 321 is used to control the inverter circuit 322 to output a three-phase (U / V / W) current (e.g., direct-axis alternating current) to the motor 33.

[0075] , and, controlling the stopping and running of the liquid pump 35. The inverter circuit 322 in the figure is an exemplary three-phase full-bridge inverter circuit, and can also be other inverter circuits, which is not limited in the present application.

[0076] The motor 33 is a three-phase AC motor. An insulating coolant flows in the motor 33, and when the motor 33 generates heat, the heat is transferred to the insulating coolant.

[0077] The heat exchanger 34 is disposed around the battery 31 for performing heat exchange with the battery 31 , and an insulating coolant flows in the heat exchanger 34 .

[0078] The liquid pump 35 is used to drive the insulating coolant to flow between the heat exchanger 34 and the motor 33. When the liquid pump 35 is powered on, it will also generate heat and heat the insulating coolant, which can improve the heating efficiency.

[0079] like Figure 4 As shown, the process of heating the battery by the motor includes S401-S404, wherein if the temperature of the battery is less than the battery temperature threshold, steps S401-S403 are executed, otherwise step S404 is executed:

[0080] S401 . If the temperature of the battery is lower than the battery temperature threshold, the control device 321 controls the liquid pump 35 to operate, and the insulating coolant circulates between the liquid pump 35 , the motor 33 , and the heat exchanger 34 .

[0081] S402 , the control device 321 controls the inverter circuit 322 to output direct-axis alternating current to the motor 33 , so that the motor 33 heats the insulating coolant.

[0082] S403 , the insulating coolant in the heat exchanger 34 heats the battery 31 , and the battery 31 cools the insulating coolant.

[0083] S404: If the battery temperature is greater than or equal to the battery temperature threshold, the control device 321 controls the inverter circuit 322 to stop outputting direct-axis alternating current to the motor 33, and stops heating.

[0084] It should be noted that the above process can be repeated at intervals, and there is no need to frequently detect the battery temperature.

[0085] Combine the following Figure 5 and Figure 6The structure of the motor 33 is described below:

[0086] like Figure 5 As shown, the motor 33 includes a housing 331, a stator 332 installed inside the housing 331, a rotor 333 connected to the housing 331 through a bearing, a winding 334 wound on the stator 332, and a liquid inlet 336 and a liquid outlet 337 connected to a cavity 335 in the housing 331.

[0087] like Figure 5 and Figure 6 As shown, the rotor 333 includes a rotating shaft 3331 , a rotor core 3332 installed around the rotating shaft 3331 , and a permanent magnet (not shown in the figure) installed on the rotor core 3332 .

[0088] The permanent magnet is used to generate an excitation magnetic field, and the permanent magnet may include stacked magnetic steel sheets, magnetic tiles, etc. The rotor core 3332 includes soft magnetic materials such as silicon steel sheets.

[0089] Optionally, the rotor core 3332 is provided with a first hole H1 connected to the cavity 335, the rotating shaft 3331 is provided with a second hole H2 connected to the cavity 335, and a third hole H3 is further provided between the rotating shaft 3331 and the rotor core 3332. The first hole H1 and the second hole H2 can be connected through the third hole H3, and the stator 332 can be provided with a fourth hole H4 connected to the cavity 335. The above-mentioned channels are used for flowing insulating coolant, wherein the insulating coolant flowing in the first channel H1 is used for heat exchange with the rotating shaft 3331, the insulating coolant flowing in the second channel H2 is used for heat exchange with the rotor core 3332, and the third channel H3 is used to connect the first channel H1 with the second channel H2, thereby facilitating the flow of the insulating coolant inside the motor; the stator 332 generates heat due to eddy current loss and hysteresis loss like the rotor core 3332, and also conducts heat for the winding 334, so the insulating coolant flowing in the fourth channel H4 is used for heat exchange with the stator 332.

[0090] The first hole H1 and the second hole H2 may be parallel to the radial direction of the rotating shaft 3331 , and the third hole H3 may be perpendicular to the radial direction of the rotating shaft 3331 . The fourth hole may be parallel to or perpendicular to the radial direction of the rotating shaft 3331 .

[0091] The present application does not limit the number of the first hole H1 , the second hole H2 and the third hole H3 , that is, there may be one or more.

[0092] The inlet hole 336 is used for the insulating coolant to flow in, and the outlet hole 337 is used for the insulating coolant to flow out. The insulating coolant flow direction in the figure is only an example.

[0093] In a possible implementation, the liquid inlet hole 336 includes a first liquid inlet hole, which can be disposed on the rotating shaft 3331 and communicated with the second hole H2 so that the insulating coolant can flow into the interior of the motor through the rotating shaft 3331 .

[0094] In another possible embodiment, the liquid inlet hole 336 includes a second liquid inlet hole, which is arranged at a position opposite to the winding 334 on the top of the shell 331, so that the insulating coolant flowing in from the second liquid inlet hole flows to the winding 334 under the action of gravity, thereby performing heat exchange with the winding 334.

[0095] In a possible implementation, the liquid outlet 337 may be disposed at the bottom of the housing 331 , so that the insulating coolant flows out of the motor from the liquid outlet 337 under the action of gravity.

[0096] The following describes how the control device controls the inverter circuit to output three-phase (U / V / W) current (e.g., direct-axis alternating current) to the motor to heat the battery, in conjunction with a specific control method. The control method can be applied to various states of the electric vehicle, for example, it can be detected that the battery is connected to an external charging power source, that the key is turned to the self-test position, that the start button is pressed, that the keyless start is triggered, and during the driving of the electric vehicle.

[0097] Specifically, Figure 7 As shown, the control method includes S701-S702:

[0098] S701. If the temperature of the battery is lower than the battery temperature threshold, the control device controls the inverter circuit to output direct-axis alternating current to the winding.

[0099] If the battery temperature is lower than the battery temperature threshold, it means that the battery temperature is too low, which affects the battery performance. Therefore, the control device can control the inverter circuit to output direct-axis alternating current to the winding to heat the battery.

[0100] The present application does not limit the waveform of the direct-axis alternating current, for example, it can be a sine wave, a triangle wave, a sawtooth wave, etc.

[0101] The frequency and current of the direct-axis alternating current can be fixed values, or can be adjusted dynamically. If the frequency or current of the direct-axis alternating current is higher, the heating power of the motor will be higher and the heating time of the battery will be shorter; if the frequency or current of the direct-axis alternating current is lower, the heating power of the motor will be lower and the heating time of the battery will be longer, but it can prevent the motor from overheating and damaging the motor. For the specific adjustment process, refer to Figure 8 and Fig. 9 Related description.

[0102] In addition, the control device can control the inverter circuit to output a quadrature axis current to the winding, that is, the quadrature axis current can be zero or non-zero. Since the quadrature axis current is non-zero, the motor will generate torque. Therefore, when the electric vehicle is stationary, in order to avoid motor vibration, the quadrature axis current can be zero. When the electric vehicle is running, the quadrature axis current can be non-zero to drive the motor shaft to rotate and drive the electric vehicle to run normally. During the running of the electric vehicle, the motor can still be heated by the direct-axis alternating current, so the battery can still be heated.

[0103] S702. Otherwise, the control device controls the inverter circuit not to output direct-axis alternating current to the winding.

[0104] That is, the battery does not need to be heated to save battery energy. For example, during the vehicle driving process, the control device can control the inverter circuit to output quadrature-axis current to the winding and stop outputting direct-axis alternating current to the winding. The saved power is used to generate the torque of the motor, thereby improving the motor efficiency.

[0105] It should be noted that during the battery heating process, the above process can be executed again at a certain interval. If the battery temperature is greater than or equal to the battery temperature threshold, no direct-axis alternating current is output to the winding and the battery heating is stopped.

[0106] Optional, such as Figure 8 As shown, the control method may further include steps S801-S802 and step S803. There is no sequential execution order for steps S801-S802 and step S803:

[0107] S801. A control device determines a temperature of a rotor of a motor according to at least one of a temperature of a housing of the motor, a temperature of a winding, a temperature of an insulating coolant flowing out of the motor, and an ambient temperature.

[0108] In the embodiment of the present application, since the heated shaft, rotor core, and permanent magnet are all located on the rotor, the temperature of the rotor will be very high, and the permanent magnet will demagnetize at high temperatures, so the temperature of the rotor must be monitored to prevent it from being too high. The rotor will rotate, so it is not suitable to install a temperature sensor to directly measure its temperature. Therefore, a mapping table of the temperature of the motor housing, the temperature of the winding, the temperature of the insulating coolant flowing out of the motor, and at least one of the ambient temperature and the temperature of the rotor can be established by experimental calibration, and the temperature of the rotor can be determined by a similar method to Table 1.

[0109] Table 1

[0110] Case temperature Winding temperature Insulation coolant temperature Ambient temperature Rotor temperature A1 B1 C1 D1 E1 A2 B2 C2 D2 E2 A3 B3 C3 D3 E3 A4 B4 C4 D4 E4

[0111] S802. The control device adjusts the current intensity of the direct-axis alternating current according to the temperature of the rotor.

[0112] Optional, such as Fig. 9 or Fig.10 As shown, step S802 includes:

[0113] S8021. If the temperature of the rotor is greater than the first rotor temperature threshold, the control device adjusts the current intensity of the direct-axis alternating current to the first current intensity.

[0114] S8022. If the temperature of the rotor is lower than the second rotor temperature threshold, the control device adjusts the current intensity of the direct-axis alternating current to the second current intensity.

[0115] Otherwise, the current intensity of the direct-axis alternating current is kept unchanged. That is, if the temperature of the rotor is less than or equal to the first rotor temperature threshold and greater than or equal to the second rotor temperature threshold, the current intensity of the direct-axis alternating current is kept unchanged.

[0116] The first rotor temperature threshold is greater than the second rotor temperature threshold, and the first current intensity is less than the second current intensity, that is, the first current intensity is a small current, and the second current intensity is a large current. When the temperature of the rotor is high, heating the motor with a small current can prevent the motor from overheating and demagnetizing the permanent magnet; when the temperature of the rotor is low, heating the motor with a large current can increase the heating power and reduce the time of heating the battery.

[0117] S803, the control device adjusts the frequency of the direct-axis alternating current according to whether the battery is connected to an external charging power source and the output voltage of the battery.

[0118] Optional, such as Fig. 9 or Fig.10 As shown, step S803 includes S8031-S8032:

[0119] S8031. If the battery is connected to an external charging power source, or if the battery is not connected to an external charging power source and the output voltage of the battery is greater than a first voltage threshold, the control device adjusts the frequency of the direct-axis alternating current to a first frequency.

[0120] When the battery is connected to an external charging power source, the battery energy will not be consumed, and the battery power will not be too low to start normally. At this time, the inverter circuit can be controlled to output direct-axis alternating current to the winding with a higher current intensity and / or a higher frequency to improve the heating efficiency of the motor and reduce the heating time of the battery.

[0121] When the battery is not connected to an external charging power source, the motor terminal voltage is proportional to the frequency of the direct-axis AC input when the amplitude of the direct-axis AC input is constant. The higher the frequency of the direct-axis AC, the greater the motor terminal voltage. When the motor terminal voltage is higher than the battery output voltage (i.e., bus voltage), the battery will not be able to supply power to the motor normally.

[0122] Therefore, when the output voltage of the battery is high, direct-axis alternating current is output to the winding at a higher frequency to improve the heating efficiency of the motor and reduce the heating time of the battery.

[0123] S8032: If the battery is not connected to an external charging power source and the output voltage of the battery is less than or equal to the first voltage threshold and greater than the second voltage threshold, the control device adjusts the frequency of the direct-axis alternating current to the second frequency.

[0124] The first voltage threshold is greater than the second voltage threshold, and the first frequency is greater than the second frequency, that is, the first frequency is a high frequency, and the second frequency is a low frequency.

[0125] As described in step S8031, when the output voltage of the battery is low, direct-axis alternating current can be output to the winding at a lower frequency to prevent the terminal voltage of the motor from being too high and causing the battery to be unable to supply power to the motor.

[0126] In addition, if the battery is not connected to an external charging power source and the output voltage of the battery is less than or equal to the second voltage threshold, step S702 is performed. At this time, the battery power is too low and the battery cannot be heated by motor heating.

[0127] It should be noted that if Fig. 9 As shown, in one possible implementation, the current intensity and frequency of the direct-axis alternating current can be independently controlled.

[0128] like Fig.10 As shown in FIG. 1 , in another possible implementation, the current intensity and frequency of the direct-axis alternating current are both controlled by the temperature of the rotor, that is, if the temperature of the rotor is greater than the first rotor temperature threshold, step S8021 and step S8032 are executed. A coordinate system is established by using the temperature of the rotor and the output voltage of the battery. The relationship between the current intensity and frequency of the direct-axis alternating current is as follows: Fig.11 shown.

[0129] The motor, motor controller, heat exchange system and control method provided in the embodiments of the present application input cross-axis alternating current into the windings of the motor, so that the rotating shaft, rotor core and stator of the motor rotor are heated due to eddy current loss and hysteresis loss, the permanent magnets of the rotor are heated due to eddy current loss, and the windings are heated due to copper loss. Therefore, compared with heating that relies solely on copper loss in the windings, higher heating power and heating efficiency can be provided, and the heating speed can be accelerated.

[0130] The present application also provides a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium. When the computer program is executed on a computer or a processor, Figure 7-10 The control method involved is executed.

[0131] The present application also provides a computer program product including instructions. When the instructions are executed on a computer or a processor, Figure 7-10 The control method involved is executed.

[0132] The present application provides a chip system, which includes a processor for executing a motor controller. Figure 7-10 The control methods involved.

[0133] In one possible design, the chip system also includes a memory, which is used to store necessary program instructions and data. The chip system may include a chip, an integrated circuit, or a chip and other discrete devices, which is not specifically limited in the embodiments of the present application.

[0134] Among them, the computer-readable storage medium, computer program product or chip system provided in this application is used to execute the method described above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the implementation methods provided above and will not be repeated here.

[0135] The processor involved in the embodiments of the present application may be a chip. For example, it may be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0136] The memory involved in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0137] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0138] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0139] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0140] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0141] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0142] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0143] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loading and executing a computer program instruction on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or may contain one or more servers, data centers and other data storage devices that can be integrated with a medium. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0144] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A motor, characterized in that: The motor comprises a rotor, a stator and a winding, wherein the rotor comprises a rotating shaft, a rotor core mounted around the rotating shaft and a permanent magnet mounted on the rotor core, and the winding is wound on the stator, wherein: The rotor core comprises a first hole, and the first hole penetrates the rotor core along the axial direction of the rotor core; The rotating shaft comprises a second hole, and the second hole penetrates the rotating shaft along the axial direction of the rotating shaft; The motor further includes a third hole, and the third hole is used to connect the first hole and the second hole.

2. The motor according to claim 1, characterized in that The rotor core includes a plurality of the first holes, and the plurality of the first holes are evenly distributed along the circumference of the rotor core.

3. The motor according to claim 1 or 2, characterized in that: The rotating shaft comprises a first liquid inlet hole, which is arranged on an end surface of the rotating shaft. The first liquid inlet hole is communicated with the second hole channel, and the coolant flows into the second hole channel through the first liquid inlet hole.

4. The motor according to any one of claims 1 to 3, characterized in that: The inner diameter of the second hole is greater than the inner diameter of the first hole, and the inner diameter of the second hole is greater than the inner diameter of the third hole.

5. The motor according to any one of claims 1 to 4, characterized in that: The stator comprises a fourth hole, and the fourth hole penetrates the stator along the axial direction of the stator.

6. The motor according to claim 5, characterized in that Along the radial direction of the stator, the distance between the fourth hole and the center of the stator is greater than the distance between the fourth hole and the outer surface of the stator.

7. The motor according to claim 5 or 6, characterized in that: The motor includes a shell, which is used to accommodate the stator, the rotor and the winding. The rotor is connected to the shell through a bearing, and the first hole, the second hole and the fourth hole are all connected to the cavity of the shell.

8. The motor according to claim 7, characterized in that The shell includes a second liquid inlet hole and a liquid outlet hole, wherein the second liquid inlet hole is arranged at a position on the top of the shell opposite to the winding, and the liquid outlet hole is arranged at the bottom of the shell, and the insulating coolant flows into the shell from the second liquid inlet hole to cool the winding and flows out of the shell from the liquid outlet hole.

9. The motor according to any one of claims 1 to 8, characterized in that: The motor includes a plurality of groups of the third holes, each group of the third holes is used to connect one of the first holes and one of the second holes, and each group of the third holes includes two third holes arranged along the axial direction of the rotating shaft.

10. The motor according to claim 9, characterized in that Along the axial direction of the rotating shaft, two third holes in each group of the third holes are arranged on both sides of the midpoint of the rotating shaft, and the distances between the two third holes and the midpoint of the rotating shaft are unequal.

11. The motor according to any one of claims 1 to 10, characterized in that: The rotating shaft further includes a winding cooling hole, which is arranged at a position opposite to the end of the winding, the winding cooling hole is communicated with the second channel, and the coolant flows to the end of the winding through the winding cooling hole.

12. A system, characterized in that: The system comprises a motor, a housing and a motor controller according to any one of claims 1 to 11, wherein: The housing is used to accommodate the rotor, the stator and the winding; The motor controller includes a control device and an inverter circuit, wherein the control device is used to control the inverter circuit to output three-phase current to the motor.

13. The system according to claim 12, characterized in that The inverter circuit is used to receive power from a power battery and output the direct-axis alternating current to the winding of the motor. The direct-axis alternating current generates heat on the winding, and the heat generated on the winding heats the power battery through a heat exchanger.

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