Motor heating method and device, motor controller, electric vehicle and storage medium

Abstract

The application discloses a motor heating method and device, a motor controller, an electric vehicle and a storage medium, relates to the technical field of electric vehicles, and is applied to the motor controller. The method comprises the following steps: obtaining a motor heating instruction; obtaining a target high-frequency rotating current vector according to the motor heating instruction, wherein the target high-frequency rotating current vector comprises a target current amplitude and a target rotating frequency; and controlling the motor to work in a step-out operation mode according to the target high-frequency rotating current vector, so as to generate motor loss, wherein the motor loss comprises copper loss and iron loss. The application solves the problem that the motor heating in the prior art is not balanced among three-phase windings, and influences the performance of the motor, and achieves the effect of improving the efficiency of heating the power battery through motor heating in the electric vehicle.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a method and apparatus for heating an electric motor, a motor controller, an electric vehicle, and a storage medium. Background Technology

[0002] In the electric vehicle industry, in low-temperature environments, the power battery is heated before starting the vehicle. Currently, the common method for heating the power battery in electric vehicles in low-temperature environments is for the battery to discharge to the motor windings. During this process, in addition to the heat generated by the battery's internal resistance, the motor also generates heat during operation. The heat generated by the motor is then transferred to the battery through a thermal management system, thus achieving heating.

[0003] However, in this method, due to the different currents in each phase winding of the motor, there is an uneven heating problem in the three-phase windings, which cannot fully utilize the heating capacity of the three-phase windings. The phase winding with more heat generation ages faster, which can easily affect the motor performance. Summary of the Invention

[0004] The main objective of this invention is to provide a method and apparatus for heating an electric motor, a motor controller, an electric vehicle, and a storage medium, aiming to solve the problem of uneven heating of the three-phase windings in existing motor heating technologies, which affects motor performance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for heating an electric motor, the method comprising:

[0007] Obtain the motor heating command;

[0008] The target high-frequency rotating current vector is obtained based on the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0009] The motor is controlled to operate in a stepless mode based on the target high-frequency rotating current vector control, which generates motor losses, including copper losses and iron losses.

[0010] Optionally, in the above-mentioned motor heating method, after controlling the motor to operate in a stepless operation mode according to the target high-frequency rotating current vector to generate motor losses, the method further includes:

[0011] Obtain the motor heating stop command;

[0012] The motor is controlled to exit the out-of-step operation mode based on the motor overheating stop command.

[0013] Optionally, the above-mentioned method for heating the motor further includes:

[0014] The motor temperature is acquired while the motor is operating in stepless mode.

[0015] When the motor temperature reaches the over-temperature protection threshold, the target current amplitude of the target high-frequency rotating current vector is reduced, and the motor is controlled to operate in the out-of-step operation mode according to the adjusted target high-frequency rotating current vector.

[0016] Optionally, in the above-mentioned motor heating method, controlling the motor to operate in a stepless running mode based on the target high-frequency rotating current vector includes:

[0017] The motor is controlled by a rotational frequency growth mode. In this mode, the current amplitude of the high-frequency rotating current vector used to control the motor is kept at zero, and the rotational frequency is gradually increased to the target rotational frequency.

[0018] The motor is controlled in a current amplitude growth mode. In this mode, the rotation frequency of the high-frequency rotating current vector used to control the motor is kept at the target rotation frequency, and the current amplitude is gradually increased to the target current amplitude.

[0019] The motor is controlled by a high-frequency rotating current vector control system with the current amplitude as the target current amplitude and the rotation frequency as the target rotation frequency.

[0020] Optionally, in the above-mentioned motor heating method, controlling the motor to exit the out-of-step operation mode includes:

[0021] The motor is controlled in a current amplitude reduction mode. In this mode, the current amplitude of the high-frequency rotating current vector used to control the motor gradually decreases to zero, while the rotation frequency remains at the target rotation frequency.

[0022] The motor is controlled in a reduced rotation frequency mode. In this mode, the rotation frequency of the high-frequency rotating current vector used to control the motor gradually decreases to zero, while the current amplitude remains zero.

[0023] In a second aspect, the present invention provides a motor heating device, the device comprising:

[0024] The instruction acquisition module is used to acquire motor heating instructions;

[0025] The data acquisition module is used to obtain the target high-frequency rotating current vector according to the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0026] The motor control module is used to control the motor to operate in a stepless operation mode according to the target high-frequency rotating current vector, so as to generate motor losses, including copper losses and iron losses.

[0027] Thirdly, the present invention provides a motor controller, which includes a processor and a memory. The memory stores a motor heating program. When the motor heating program is executed by the processor, the motor heating method described above is implemented.

[0028] Fourthly, the present invention provides an electric vehicle, comprising:

[0029] Power battery;

[0030] Thermal management system;

[0031] Electric motor;

[0032] The motor controller described above is connected to the motor and is used to control the motor to operate in a stepless running mode to generate motor losses, which include copper losses and iron losses.

[0033] The thermal management system is used to transfer the heat generated by the motor to the power battery in order to heat the power battery.

[0034] Fifthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by one or more processors, implements the motor heating method described above.

[0035] The above-described one or more technical solutions provided by this invention can have the following advantages or at least achieve the following technical effects:

[0036] This invention proposes a method and apparatus for motor heating, a motor controller, an electric vehicle, and a storage medium. By acquiring a motor heating command, a target high-frequency rotating current vector, including a target current amplitude and a target rotation frequency, is obtained based on the command. The motor is then controlled to operate in a stepless mode based on this target high-frequency rotating current vector, thereby generating motor losses including copper and iron losses, achieving the purpose of motor heating. This invention controls the motor to operate in a stepless mode based on the target high-frequency rotating current vector, ensuring balanced heating of the three-phase windings and simultaneously generating additional iron losses, thus improving motor heating efficiency. Furthermore, in this invention, the actual current of the motor during operation remains consistent with the commanded current for controlling the motor. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1This is a flowchart illustrating an embodiment of the motor heating method of the present invention;

[0039] Figure 2 This is a structural block diagram of the electric vehicle of the present invention;

[0040] Figure 3 This is a schematic flowchart of another embodiment of the motor heating method of the present invention;

[0041] Figure 4 This is a diagram showing the spatial relationship between the target high-frequency rotating current vector and the three-phase windings of the motor in another embodiment of the motor heating method of the present invention.

[0042] Figure 5 This is a schematic diagram of the functional modules of the motor heating device of the present invention;

[0043] Figure 6 for Figure 5 Block diagram of the motor control module.

[0044] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] It should be noted that in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. In this invention, unless otherwise expressly specified and limited, the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements or an interaction between two elements. In this invention, if descriptions refer to "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of those features. In this invention, the use of suffixes such as "module," "component," or "unit" to denote elements is merely for illustrative purposes and has no specific meaning in itself. Therefore, "module," "component," or "unit" can be used interchangeably. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the technical solutions of the various embodiments can be combined with each other; however, this is based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0047] In the field of electric vehicles, the discharge efficiency of power batteries is low in low-temperature environments, which reduces the vehicle's range. Furthermore, high-current charging in low-temperature environments can cause lithium plating in the battery, resulting in irreversible damage and reducing battery safety. Therefore, in low-temperature environments, the power battery is heated before starting the vehicle.

[0048] Analysis of existing technologies reveals that the common method for heating the power battery in electric vehicles under low-temperature conditions is for the battery to discharge to the motor windings. In this process, in addition to the heat generated by the battery's internal resistance, the motor also generates heat during operation. The heat generated by the motor is then transferred to the battery through a thermal management system. Specifically, when the vehicle is stationary, the motor controller inputs a specified d-axis current to the motor, sets the q-axis current to zero to ensure no torque output, and calculates the amplitude and phase of the current in each phase of the motor winding based on the current rotor position. The current then flows through the three-phase windings, generating heat, which is then transferred to the battery through the thermal management system to achieve battery heating. However, this method suffers from uneven heating due to the different currents in each phase of the motor windings. Furthermore, it cannot fully utilize the heating capacity of the three-phase windings; the phase with higher heat generation ages faster, potentially affecting motor performance. Additionally, this method suffers from low battery heating efficiency.

[0049] In view of the technical problem in the prior art where uneven heating of the three-phase windings in motors affects motor performance, this invention provides a motor heating method, the overall idea of ​​which is as follows:

[0050] Obtain the motor heating command; obtain the target high-frequency rotating current vector based on the motor heating command, the target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency; control the motor to operate in the out-of-step operation mode based on the target high-frequency rotating current vector to generate motor losses, the motor losses include copper losses and iron losses.

[0051] The above technical solution achieves the goal of motor heating. In the motor heating solution provided in this application, the motor operates in a stepless mode based on the target high-frequency rotating current vector control. Current control of the motor is implemented in a high-frequency rotating coordinate system, ensuring that there is no attenuation between the actual current during motor operation and the command current injected into the motor. Since the motor operates in stepless mode, it does not output continuous torque; the average torque output within one electrical cycle is zero, allowing the motor to remain stationary. By using high-frequency rotating current to control the motor's operation, while ensuring balanced heating of the three-phase windings, the motor generates additional iron losses, thus improving the motor's heating efficiency.

[0052] The following detailed description, with reference to the accompanying drawings, provides a detailed explanation of the motor heating method and apparatus, motor controller, electric vehicle, and storage medium provided by the present invention through specific embodiments and implementation methods.

[0053] The motor heating method provided in this application can be applied to electric vehicles. By applying this method to electric vehicles, the heat generated by the motor can be used to heat the power battery or meet other heat requirements. When this method is applied to power battery heating, the iron losses generated by the motor can be fully utilized, improving the efficiency of heating the power battery through motor heating in electric vehicles.

[0054] Example 1

[0055] Reference Figure 1 ,like Figure 1 The diagram shows a flowchart of a motor heating method. A first embodiment of the motor heating method of the present invention is presented, which can be applied to a motor controller.

[0056] Specifically, the motor controller can store various types of data, such as instructions from any application or method within the motor controller, as well as application-related data. In this embodiment, the motor controller can include a motor heating program; the motor controller can call the stored motor heating program and perform the following operations:

[0057] Obtain the motor heating command; obtain the target high-frequency rotating current vector based on the motor heating command, the target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency; control the motor to operate in the out-of-step operation mode based on the target high-frequency rotating current vector to generate motor losses.

[0058] Based on the above motor controller, the following is combined with Figure 1 The flowchart shown illustrates the motor heating method of this embodiment in detail. The method may include the following steps:

[0059] Step S100: Obtain the motor heating command.

[0060] Optionally, the motor can be a permanent magnet synchronous motor (PM), which generates a certain amount of heat through its operation. When utilizing the motor to generate heat, there are two requirements: first, the motor winding current should be as large as possible to ensure sufficient heat generation; second, the heating of each phase winding of the motor should be uniform in order to fully utilize the heating capacity of the windings.

[0061] Optionally, when the motor controller receives the motor heating command, it determines the state of the motor. When the motor is in a stationary state, it responds to the motor heating command; when the motor is in a non-stationary state, it does not respond to the motor heating command.

[0062] The determination of a stationary state can be made by the motor controller itself or by an external system. When the motor controller makes the determination itself, it can monitor the motor speed in real time and determine whether the motor is stationary based on the detected motor speed, thereby responding to the motor heating command.

[0063] In this embodiment, the motor heating command can be obtained manually, for example, by the user initiating the motor heating command via a button, and then by the motor controller receiving it; or it can be obtained automatically, for example, by automatically generating the motor heating command in the motor controller.

[0064] Step S200: Obtain the target high-frequency rotating current vector according to the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0065] Optionally, the motor heating command may include the motor heating power. This command may also include other indicators related to motor heating, such as the motor heating temperature.

[0066] Optionally, the target high-frequency rotating current vector can be directly extracted by the motor controller from the motor heating command; or, the motor controller stores the correspondence between the motor heating power and the high-frequency rotating current vector. The correspondence between the motor heating power and the high-frequency rotating current vector is obtained by offline calibration in advance and stored in the motor controller. After the motor controller extracts the motor heating power from the motor heating command, it is obtained according to the correspondence between the motor heating power and the high-frequency rotating current vector.

[0067] Step S300: Control the motor to operate in out-of-step mode according to the target high-frequency rotating current vector control to generate motor losses, including copper losses and iron losses.

[0068] Specifically, the motor controller generates a motor control signal based on the target high-frequency rotating current vector, thereby generating phase current and phase voltage, which are input into the motor. Specifically, this can be applied to the motor stator to control the motor to operate in a stepless mode. At this time, the losses caused by the heating of the iron components in the motor are called iron losses, such as the motor winding core, magnets, and yoke. The losses caused by the heating of the copper components in the motor are called copper losses, such as the coils. The coils have resistance, and the phase current flowing into the motor incurs losses across this resistance.

[0069] When the motor operates in out-of-step mode, it will not output continuous torque and can focus on generating heat.

[0070] The motor heating method provided in this embodiment obtains a motor heating command, acquires a target high-frequency rotating current vector including the target current amplitude and target rotation frequency based on the motor heating command, and then controls the motor to operate in a stepless operation mode based on the target high-frequency rotating current vector to generate motor losses including copper losses and iron losses, thereby achieving the purpose of motor heating. Controlling the motor to operate in a stepless operation mode based on the target high-frequency rotating current vector ensures balanced heating of the three-phase windings of the motor, and at the same time can generate additional iron losses in the motor, which can make full use of the heat generated by the motor losses and improve the motor heating efficiency.

[0071] In one optional embodiment, the above-described motor heating method can be applied to an electric vehicle. The electric vehicle is equipped with a motor and a motor controller that controls the operation of the motor. The motor heating method can be specifically applied to the motor controller of the electric vehicle to control the motor to generate heat. The heat generated by the motor can heat the power battery or other components of the electric vehicle.

[0072] Here, we will take the heating of the power battery by the motor as an example for explanation. Figure 2 The electric vehicle shown includes a motor, a motor controller for controlling the operation of the motor, a power battery, and a thermal management system. The thermal management system transfers the heat generated by the motor to the power battery to heat the power battery.

[0073] Optionally, when issuing commands to the motor controller in an electric vehicle, the main control system can generate the commands and send them to the motor controller. Therefore, for example... Figure 2 As shown, electric vehicles can also have a main control system.

[0074] When using the heat generated by the motor to heat the power battery, there are generally two requirements: first, the motor must generate enough heat to quickly heat the battery to the target temperature; second, the heating of each phase winding of the motor must be uniform to avoid premature aging of one phase winding, which would affect the motor performance.

[0075] Based on this electric vehicle and its motor controller, in this embodiment, the motor heating method may include:

[0076] Step A100: Obtain the motor heating command.

[0077] The motor heating command can be obtained by the motor controller automatically or passively, or it can be obtained by the electric vehicle's main control system automatically generating and sending it to the motor controller. For example, when the main control system detects that the external ambient temperature is low and the user is preparing to start the vehicle, it automatically generates a motor heating command and then sends the motor heating command to the motor controller.

[0078] Optionally, when the motor controller receives the motor heating command, it determines the state of the motor. If the motor is in a stationary state, it responds to the motor heating command.

[0079] The determination of a stationary state can be achieved by the motor controller itself, or by the electric vehicle's main control system sending corresponding signal commands to the motor controller after determination.

[0080] When the motor is stationary, it responds to the motor heating command, enabling the motor to heat the power battery before starting the electric vehicle in low-temperature environments, thereby protecting the battery and improving battery discharge efficiency.

[0081] Optionally, when the motor controller detects the stationary state on its own, a speed detection module can be added to the motor controller to detect the motor speed in real time. Based on the motor speed, it can be determined that the motor is stationary in order to respond to the motor heating command.

[0082] Optionally, when the main control system of the electric vehicle determines that the motor is stationary, the main control system can determine that the motor is stationary based on data such as motor feedback information and detection information, and generate a signal command to send to the motor controller, so that the motor controller can respond to the motor heating command after receiving the signal command.

[0083] Step A200: Obtain the target high-frequency rotating current vector according to the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0084] Optionally, the motor heating command may include the motor heating power. This motor heating power can be determined according to the temperature required for heating the power battery, for example, it can be pre-determined based on the electric vehicle's configuration and stored in the main control system.

[0085] Step A300: Control the motor to operate in out-of-step mode according to the target high-frequency rotating current vector control to generate motor losses, including copper losses and iron losses.

[0086] The motor controller controls the motor to operate in a stepless mode based on the target high-frequency rotating current vector. The motor will not output continuous torque, meaning that the motor cannot drive the electric vehicle, thus ensuring that the electric vehicle will not suddenly move forward, so as to achieve battery preheating before the electric vehicle is driven.

[0087] In this embodiment, the heat generated by motor losses is used to heat the power battery, thereby improving the efficiency of heating the power battery through motor heat generation in electric vehicles, in addition to improving the motor's heating efficiency. Furthermore, the additional iron losses generated by the motor can further improve the motor's heating efficiency, thus further enhancing the efficiency of heating the power battery in electric vehicles.

[0088] Example 2

[0089] Based on the same inventive concept, referring to Figure 3 and Figure 4 This paper presents another embodiment of the motor heating method of the present invention. The motor heating method of this embodiment will be described in detail below. Figure 3 The flowchart shown illustrates that the method may include the following steps:

[0090] Step S100: Obtain the motor heating command.

[0091] The motor heating command may include the motor heating power P. heat .

[0092] Optionally, when the motor controller receives the motor heating command, it can determine the state of the motor. When the motor is in a stationary state, it responds to the motor heating command; when the motor is in a non-stationary state, it does not respond to the motor heating command.

[0093] Optionally, responding to a motor heating command includes extracting data from the motor heating command to obtain the motor heating power P. heat .

[0094] Step S200: Obtain the target high-frequency rotating current vector according to the motor heating command.

[0095] The target high-frequency rotating current vector may include the target current amplitude and the target rotation frequency.

[0096] Furthermore, the target current amplitude and target rotation frequency can be determined based on the motor's heating power P. heat The NVH (Noise, Vibration, Harshness) characteristics of the motor are obtained through pre-calibration offline. These characteristics include noise, vibration, and acoustic roughness. By storing the pre-determined correspondence between motor heating power, current amplitude, and rotational frequency in the motor controller, it can be directly invoked upon receiving a motor heating command, saving resources for the motor controller. Taking the motor's NVH characteristics into account when determining the target high-frequency rotating current vector ensures the motor operates without synchronization and reduces noise during the heating process.

[0097] Step S300: Control the motor to operate in out-of-step mode according to the target high-frequency rotating current vector control to generate motor losses, including copper losses and iron losses.

[0098] In this embodiment, the motor heating power P heat It consists of two parts:

[0099] P heat =P Cu (Is ,ω f )+P Fe (I s ,ω f )

[0100] Among them, copper loss P Cu and iron loss P Fe Both are high-frequency rotating current vectors i used to control the operation of motors. s Current amplitude I s and rotation frequency ω f An increasing function.

[0101] Through high-frequency rotating current vector i s By controlling the motor to operate in out-of-step mode, the three-phase windings of the motor can be heated evenly, and the motor can generate more iron losses, thus improving the motor's heating efficiency.

[0102] Step S400: Obtain the motor heating stop command.

[0103] Optionally, the motor heating stop command can be generated and sent by an external system. For example, when the external system detects that the motor's heating power has reached a set level, it generates a motor heating stop command and sends it to the motor controller, which then receives the command. Alternatively, the motor controller can generate the motor heating stop command itself. For example, when it detects that the actual heating power of the motor has reached the required heating power P specified in the motor heating command, it can generate the command itself. heat When the heat generated by the motor reaches the required level, a motor heating stop command is automatically generated. The specific settings can be configured according to actual needs; however, this application does not limit this.

[0104] Step S500: Control the motor to exit the out-of-step operation mode according to the motor overheating stop command.

[0105] In an optional embodiment based on the above embodiments, step S300, namely "controlling the motor to operate in out-of-step mode according to the target high-frequency rotating current vector", can be implemented by the following steps:

[0106] Step S310: Control the motor operation in a rotational frequency growth mode. In the rotational frequency growth mode, the high-frequency rotating current vector i used to control the motor operation... s Current amplitude I s Keep it at zero, rotation frequency ω f Gradually increase to the target rotation frequency.

[0107] Optional, rotation frequency ω f The method of gradually increasing to the target rotation frequency can be to gradually increase to the target rotation frequency according to a preset frequency step size.

[0108] When the rotation frequency ω f When the target rotation frequency is reached, step S320 is executed.

[0109] Step S320: Control the motor operation in current amplitude growth mode. In current amplitude growth mode, the high-frequency rotating current vector i used to control the motor operation... s rotation frequency ω f Maintain the target rotation frequency, current amplitude I s Gradually increase to the target current amplitude.

[0110] Optional, current amplitude I s The method of gradually increasing to the target current amplitude can be to gradually increase to the target current amplitude according to a preset amplitude step size.

[0111] When the current amplitude I s When the target current amplitude is reached, step S330 is executed.

[0112] Step S330: With current amplitude I s For the target current amplitude and rotation frequency ω f The high-frequency rotating current vector i is the target rotation frequency. s Control the operation of the motor.

[0113] Optionally, for the high-frequency rotating current vector i used to control motor operation s To make dynamic adjustments, first adjust the rotation frequency ω according to the preset frequency step size. f The current amplitude I gradually increases to the target rotation frequency according to the preset frequency step size, during which time the current amplitude I s Keep it at zero; when the rotation frequency ω f After reaching the target rotation frequency, the current amplitude I is then increased according to the preset amplitude step size. s The rotation frequency ω increases to the target current amplitude during this process. f Maintain the target rotational frequency; then at its current amplitude I s Once the target current amplitude is reached, maintain that target current amplitude as the current amplitude I. s The target rotation frequency is taken as the rotation frequency ω. f high-frequency rotating current vector i s This means enabling the motor to operate in a stepless running mode.

[0114] When controlling the motor operation, the high-frequency rotating current vector i is adjusted online. s Current amplitude I s and rotation frequency ω f To adjust the motor's operating mode accordingly, first increase the rotation frequency ω. f Increase the current amplitude I sThis ensures the motor can operate without steps. Conversely, first increase the current amplitude I. s Increase the rotation frequency ω f It may not achieve the desired effect of losing pace.

[0115] Optionally, step S500 above, namely "controlling the motor to exit the out-of-step operation mode according to the motor heating stop command", can be achieved by the following steps:

[0116] Step S510: Control the motor operation in a current amplitude reduction mode. In the current amplitude reduction mode, the high-frequency rotating current vector i used to control the motor operation... s Current amplitude I s Gradually decrease to zero, rotation frequency ω f Maintain the target rotation frequency.

[0117] Optional, current amplitude I s The method of gradually reducing to zero can be to gradually reduce to zero according to a preset amplitude step size. The preset amplitude step size here can be the same as or different from the preset amplitude step size in step S320, and can be set according to actual needs.

[0118] When the current amplitude I s When the value drops to zero, proceed to step S520.

[0119] Step S520: Control the motor operation in a reduced rotational frequency mode. In the reduced rotational frequency mode, the high-frequency rotating current vector i used to control the motor operation... s rotation frequency ω f Gradually decreasing to zero, current amplitude I s Keep it at zero.

[0120] Optional, rotation frequency ω f The frequency can be gradually reduced to zero by following a preset frequency step size. The preset frequency step size here can be the same as or different from the preset frequency step size in step S310, and can be set according to actual needs.

[0121] In this embodiment, the current amplitude I is first set... s The amplitude decreases to zero according to a preset step size, during which the rotation frequency ω f The current amplitude I remains unchanged; s After decreasing to zero, the rotation frequency ω f Then reduce it to zero according to the preset frequency step size. Current amplitude I s First, reduce the speed to ensure the motor stops overheating; then reduce the rotational frequency ω. f This ensures that the motor remains stationary.

[0122] If current is input to the motor, the motor may continue to heat up, which could cause the motor to overheat beyond the set temperature and potentially lead to other problems.

[0123] In an optional embodiment of this application, the process of the motor controller controlling the motor operation is as follows:

[0124] In determining the high-frequency rotating current vector i used to control the motor operation s Current amplitude I s and rotation frequency ω f After that, the command current i can be obtained. s_ref .

[0125] Specifically, the command current i s_ref Including the d-axis component of the command current i d_ref and command current q-axis component i q_ref It can be based on the high-frequency rotating current vector i s Current amplitude I s 1. Initial phase θ0, determine the d-axis component i of the command current. d_ref and command current q-axis component i q_ref The specific calculation formula is as follows:

[0126] i d_ref =I s ·cos(θ0)

[0127] i q_ref =I s sin(θ0)

[0128] Here, we can set the initial phase θ0 = 0 to obtain i d_ref =i s_ref i q_ref =0.

[0129] Secondly, according to the command current i s_ref The feedback current of the motor is PI-regulated to obtain a voltage signal, wherein the current control of the motor is based on a high-frequency rotating coordinate system.

[0130] Optionally, the feedback current includes the d-axis component i of the feedback current. d and feedback current q-axis component i q Specifically, it can be based on the real-time detection of the motor's three-phase winding current and phase θ. f It is obtained by performing the abc / dq transformation. The abc / dq transformation is a coordinate system transformation from the abc coordinate system (three-phase rotating coordinate system) to the dq coordinate system (two-phase rotating coordinate system).

[0131] The three-phase winding current includes the U-phase winding current i u V-phase winding current i vW-phase winding current i w It can be obtained by detecting the instantaneous current of the three-phase windings U, V, and W of the motor; phase θ f The phase difference between phase voltage and phase current can be determined by the high-frequency rotating current vector i. s rotation frequency ω f The formula is obtained from the initial phase θ0, and the specific calculation formula is as follows:

[0132] θ f =∫ω f dt+θ0

[0133] In this embodiment, the command current i can be calculated before performing PI regulation. s_ref The difference between the current and the feedback current is specifically calculated by dividing the command current into d-axis components i. d_ref With the d-axis component i of the feedback current d The amplitude difference between them yields the d-axis amplitude difference ΔI. d and the command current q-axis component i q_ref With the q-axis component i of the feedback current q The amplitude difference between them yields the q-axis amplitude difference ΔI. q The specific calculation formula is as follows:

[0134] ΔI d =i sd_ref -i d

[0135] ΔI q =i sq_ref -i q

[0136] Obtain the command current i s_ref After obtaining the difference from the feedback current, PI control based on a high-frequency rotating coordinate system is performed. Specifically, the d-axis amplitude difference ΔI can be adjusted. d And the difference in amplitude ΔI along the q-axis q The input is fed into a PI (Proportional Integral) controller in a high-frequency rotating coordinate system, which then outputs the corresponding voltage signal.

[0137] Employing a PI controller in a high-frequency rotating coordinate system ensures that the actual phase current generated by the motor matches the commanded current. Compared to existing PI controllers in a synchronous coordinate system based on AC power, this PI controller processes DC power. For DC power, the high-frequency rotating coordinate system PI controller offers better control accuracy and better tracking of DC power commands, thereby improving the effect of current regulation.

[0138] Then, the voltage signal is subjected to space vector pulse width modulation (SVPWM) to obtain the pulse width modulated signal.

[0139] Optionally, the voltage signal can first undergo a dq / αβ transformation, and then SVPWM can be used to generate the pulse width modulation signal and output the pulse width modulation signal. The dq / αβ transformation is a linear coordinate transformation from the dq coordinate system (two-phase rotating coordinate system) to the αβ coordinate system (two-phase stationary coordinate system).

[0140] In this embodiment, firstly based on the voltage signal and phase θ f The dq / αβ transform is performed, and then the transformed voltage signal based on the αβ coordinate system is subjected to space vector pulse width modulation to obtain the pulse width modulated signal.

[0141] Finally, the inverter drives the motor according to the pulse width modulation signal, controlling the high-frequency rotating current vector i. s Current amplitude I s and rotation frequency ω f Work.

[0142] Optionally, the pulse width modulation signal can be input into the inverter to drive the motor, generating motor losses and causing the motor to heat up.

[0143] In this embodiment, the pulse width modulation signal and DC voltage V can be used as the basis. DC Inversion is performed, using an inverter to convert direct current (DC) to alternating current (AC), which is then applied to the motor stator to enable the motor to operate in a stepless mode. Optionally, a DC voltage V can be provided by a DC power supply. DC It supplies power to the inverter.

[0144] During the process of the above-mentioned motor controller controlling the motor operation, the formula for calculating the command current of the three-phase windings of the motor during operation is as follows:

[0145] I u =I s ·cos(θ f )

[0146] I v =I s ·cos(θ f -2π / 3)

[0147] I w =I s ·cos(θ f +2π / 3)

[0148] Among them, I u Indicates the U-phase command current, I vIndicates the V-phase command current, I w This indicates the command current for phase W.

[0149] By controlling the motor operation in the above manner and comparing the three-phase command current with the actual three-phase winding current when the motor is working, it can be seen that the difference between the actual current and the command current is not significant. This indicates that the actual current when the motor is working in this embodiment is consistent with the command current for controlling the motor, thus ensuring the motor's heating power and allowing for better utilization of the heat generated by the motor in the future.

[0150] like Figure 4 The diagram shows the spatial relationship between the high-frequency rotating current vector and the three-phase windings of the motor. Combined with the above formula for calculating the command current of the three-phase windings of the motor, it can be seen that in this embodiment, the phase difference of the command current of the three-phase windings of the motor is 120 degrees, and the current of the three-phase windings is balanced. This indicates that the three-phase windings of the motor in this embodiment heat up evenly, so as to fully obtain the heat generated by the motor and not cause significant damage to the motor.

[0151] Furthermore, based on the motor torque calculation formula:

[0152]

[0153] Among them, T e The motor torque is represented by p, the number of pole pairs is represented by ψ. f L represents the rotor flux linkage of the motor. d L represents the d-axis component of the motor inductance. q Represents the q-axis component of the motor inductance;

[0154] It is evident that the average torque is zero within one electrical cycle of the motor, proving that the motor operates in out-of-step mode and will not output continuous torque.

[0155] In an optional embodiment of the above embodiments, the motor heating method may further include:

[0156] Step S600: During the process of the motor operating in the out-of-step mode, obtain the motor temperature.

[0157] Optionally, the motor temperature can be acquired in real time during the motor's out-of-step operation, or the motor temperature can be acquired at predetermined intervals.

[0158] Step S700: When the motor temperature reaches the over-temperature protection threshold, reduce the target current amplitude of the target high-frequency rotating current vector, and control the motor to operate in the out-of-step operation mode according to the adjusted target high-frequency rotating current vector.

[0159] Optionally, during the process of controlling the motor to operate in the out-of-step operation mode according to steps S310-S330, the motor temperature can be detected. When the motor temperature reaches the over-temperature protection threshold, the target current amplitude in the target high-frequency rotating current vector can be reduced as the new target current amplitude. Combined with the aforementioned target rotation frequency, the motor can be controlled to continue operating in the out-of-step operation mode.

[0160] The over-temperature protection threshold can be a threshold value or a range value, which can be set according to actual needs.

[0161] Steps S600 and S700 provide temperature protection for the motor to prevent excessive heat from affecting subsequent production operations and the motor's lifespan.

[0162] The motor heating method provided in this embodiment solves the problems of uneven heating of existing motor windings and underutilization of motor iron losses.

[0163] In an optional embodiment of the above examples, the above-described motor heating method can be applied to, for example... Figure 2 The electric vehicle shown is equipped with a motor and a motor controller that controls the motor's operation. Here, the heating of the power battery by the motor's heat is used as an example for explanation. Compared to the traditional approach of adding a heating device to the power battery, the method in this embodiment controls the heating of the motor windings, using the heat generated by the motor to heat the power battery, which can reduce costs and save internal space.

[0164] Optional, such as Figure 2 As shown, the electric vehicle may also include a power battery, a thermal management system, and a main control system.

[0165] Based on the electric vehicle and its motor controller, in this specific embodiment, the motor heating method may include:

[0166] Step A100: Obtain the motor heating command.

[0167] Optionally, when the motor controller receives the motor heating command, it determines the state of the motor. If the motor is in a stationary state, it responds to the motor heating command.

[0168] Step A200: Obtain the target high-frequency rotating current vector according to the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0169] Optionally, the motor heating command may include the motor heating power.

[0170] Step A300: Control the motor to operate in out-of-step mode according to the target high-frequency rotating current vector control to generate motor losses, including copper losses and iron losses.

[0171] In an optional embodiment of the above specific implementation, step A300, namely "controlling the motor to operate in out-of-step mode according to the target high-frequency rotating current vector to generate motor losses", can be achieved by the following steps:

[0172] Step A310: Control the motor operation in rotational frequency growth mode. In rotational frequency growth mode, the high-frequency rotating current vector i used to control the motor operation... s Current amplitude I s Keep it at zero, rotation frequency ω f Gradually increase to the target rotation frequency;

[0173] Step A320: Control the motor operation in current amplitude growth mode. In current amplitude growth mode, the high-frequency rotating current vector i used to control the motor operation... s rotation frequency ω f Maintain the target rotation frequency, current amplitude I s Gradually increase to the target current amplitude;

[0174] Step A330: With current amplitude I s For the target current amplitude and rotation frequency ω f The high-frequency rotating current vector i is the target rotation frequency. s Control the operation of the motor.

[0175] The specific implementation of steps A310-A330 above can be referred to the specific description of the above embodiments. The specific process of the motor controller controlling the motor operation can also be referred to the specific description of the above embodiments, and will not be repeated here.

[0176] In an optional embodiment of the above specific implementation, after step A300, namely step "controlling the motor to operate in out-of-step mode according to the target high-frequency rotating current vector to generate motor loss", the heat generated by the motor loss can be used to heat the power battery.

[0177] Optionally, heating the power battery includes transferring heat generated by the motor to the power battery through a thermal management system in the electric vehicle. When the heat is transferred to the power battery via the thermal management system, in addition to the heat generated by the battery's internal resistance, a greater portion of the heat comes from the motor windings. Compared to existing technologies, this increases heat generation, allowing the battery to reach the preset temperature more quickly and improving heating efficiency.

[0178] In an optional embodiment of the above specific implementation method, after step A300, the motor heating method may further include:

[0179] Step A400: Obtain the motor heating stop command.

[0180] Optionally, the motor controller can generate the motor heating stop command itself or generate and send it from the main control system. For example, when the main control system detects that the temperature of the power battery in the electric vehicle has reached the set temperature, it generates the motor heating stop command and sends it to the motor controller.

[0181] Step A500: Control the motor to exit the out-of-step operation mode according to the motor overheating stop command.

[0182] Optionally, step A500 above can be implemented by the following steps:

[0183] Step A510: Control the motor operation in current amplitude reduction mode. In current amplitude reduction mode, the high-frequency rotating current vector i used to control the motor operation... s Current amplitude I s Gradually decrease to zero, rotation frequency ω f Maintain the target rotation frequency;

[0184] Step A520: Control the motor operation in a reduced rotational frequency mode. In the reduced rotational frequency mode, the high-frequency rotating current vector i used to control the motor operation... s rotation frequency ω f Gradually decreasing to zero, current amplitude I s Keep it at zero.

[0185] The specific implementation methods of steps A510 and A520 described above can be found in the detailed description of the above embodiments, and will not be repeated here.

[0186] In this specific embodiment, the motor operates in out-of-step mode and does not output continuous torque, meaning the motor cannot drive the electric vehicle. While the motor is working, the electric vehicle does not move forward, ensuring that the vehicle does not suddenly move forward, thus achieving battery preheating before driving. Furthermore, based on the high heating efficiency of the motor, the battery preheating efficiency is improved, enabling the preset battery temperature to be quickly reached in low-temperature application environments for normal starting of the electric vehicle. This also increases the lifespan of the power battery in the electric vehicle.

[0187] It should be noted that more implementation details of the above method embodiments and their respective steps can be found in the description of the specific implementation in Embodiment 1. For the sake of brevity, these details will not be repeated here.

[0188] Example 3

[0189] Based on the same inventive concept, referring to Figure 5 The first embodiment of the motor heating device of the present invention is presented, which can be a virtual device. The following is in conjunction with... Figure 5The schematic diagram of the functional modules of the motor heating device shown illustrates the motor heating device provided in this embodiment, which may include:

[0190] The instruction acquisition module is used to acquire motor heating instructions;

[0191] The data acquisition module is used to obtain the target high-frequency rotating current vector according to the motor heating command. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency.

[0192] The motor control module is used to control the motor to operate in a stepless operation mode according to the target high-frequency rotating current vector, so as to generate motor losses, including copper losses and iron losses.

[0193] Furthermore, the motor heating device may also include:

[0194] The instruction acquisition module is also used to acquire motor heating stop instructions;

[0195] The motor control module is also used to control the motor to exit the out-of-step operation mode according to the motor overheating stop command.

[0196] Furthermore, the motor heating device may also include:

[0197] The temperature detection module is used to acquire the motor temperature when the motor is operating in the stepless operation mode;

[0198] The data acquisition module is also used to reduce the target current amplitude of the target high-frequency rotating current vector when the motor temperature reaches the over-temperature protection threshold, and to control the motor to operate in the out-of-step operation mode according to the adjusted target high-frequency rotating current vector.

[0199] Furthermore, such as Figure 6 The diagram shown is a block diagram of a motor control module, which may include:

[0200] The mode switching unit is used to control the motor operation in a rotation frequency increasing mode. In the rotation frequency increasing mode, the current amplitude of the high-frequency rotating current vector used to control the motor operation remains at zero, and the rotation frequency gradually increases to the target rotation frequency. In the current amplitude increasing mode, the rotation frequency of the high-frequency rotating current vector used to control the motor operation remains at the target rotation frequency, and the current amplitude gradually increases to the target current amplitude. The motor operation is also controlled by a high-frequency rotating current vector with a current amplitude of the target current amplitude and a rotation frequency of the target rotation frequency.

[0201] Furthermore, the mode switching unit is also used to control the motor operation in a current amplitude reduction mode. In the current amplitude reduction mode, the current amplitude of the high-frequency rotating current vector used to control the motor operation gradually decreases to zero, while the rotation frequency remains at the target rotation frequency. In the rotation frequency reduction mode, the rotation frequency of the high-frequency rotating current vector used to control the motor operation gradually decreases to zero, while the current amplitude remains at zero.

[0202] Furthermore, the motor control module may also include:

[0203] The phase calculation unit is used to calculate the phase based on the high-frequency rotating current vector i used to control the operation of the motor. s rotation frequency ω f And the initial phase θ0, to obtain the phase θ f ;

[0204] abc / dq transform unit, such as Figure 6 The abc / dq ratio shown is used to calculate the real-time detected three-phase winding current and phase θ of the motor. f Perform an abc / dq transformation to obtain the feedback current. The three-phase winding currents include the U-phase winding current i. u V-phase winding current i v W-phase winding current i w The feedback current includes the d-axis component i of the feedback current. d and feedback current q-axis component i q ;

[0205] The mode switching unit is also used to determine the high-frequency rotating current vector i used to control the operation of the motor. s Current amplitude I s and rotation frequency ω f Obtain the command current i s_ref Command current i s_ref Including the d-axis component of the command current i d_ref and command current q-axis component i q_ref ;

[0206] PI control unit, such as Figure 6 The two PIs shown are used to determine the command current i s_ref The voltage signal is obtained by PI regulation of the feedback current; specifically, the d-axis component i of the command current is calculated separately. d_ref With the d-axis component i of the feedback current d The amplitude difference between them yields the d-axis amplitude difference ΔI. d and the command current q-axis component i q_ref With the q-axis component i of the feedback current q The amplitude difference between them yields the q-axis amplitude difference ΔI. qThen, the d-axis amplitude difference ΔI d And the difference in amplitude ΔI along the q-axis q The input is fed into a PI controller in a high-frequency rotating coordinate system, and the output is a voltage signal.

[0207] dq / αβ transform unit, such as Figure 6 The dq / αβ shown is used based on the voltage signal and phase θ f Perform dq / αβ transformation to obtain the voltage signal based on the αβ coordinate system;

[0208] Pulse width modulation unit, such as Figure 6 The SVPWM shown is used to perform space vector pulse width modulation on a voltage signal based on the αβ coordinate system to obtain a pulse width modulated signal;

[0209] Inverter drive unit, such as Figure 6 The inverter shown is used to drive a motor according to a pulse width modulation signal, rotating at a high frequency according to the current vector i. s Current amplitude I s and rotation frequency ω f The motor works to generate heat.

[0210] It needs to be explained that, Figure 5 and Figure 6 The structure shown does not constitute a limitation on the motor heating device of the present invention. It may include more or fewer components than shown, or combine certain components, or have different component arrangements. The functions and corresponding technical effects achieved by each module and its internal components in the motor heating device provided in this embodiment can be referred to the description of the specific implementation methods in the various embodiments of the motor heating method of the present invention. For the sake of brevity, they will not be repeated here.

[0211] Example 4

[0212] Based on the same inventive concept, this embodiment provides a motor controller. The motor controller may include a processor and a memory, the memory storing a motor heating program. When the motor heating program is executed by the processor, it implements the motor heating method as described in Embodiment 1 or Embodiment 2 above.

[0213] Specifically, the memory is used to store various types of data, which may include, for example, instructions for any application or method in the motor controller, as well as application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Random Access Memory (RAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk, etc. Optionally, the memory can also be a processor-independent storage device.

[0214] The processor is used to call the motor heating program stored in the memory and execute the motor heating method as described above. The processor can be an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute all or part of the steps of the various embodiments of the motor heating method described above.

[0215] It should be noted that the motor controller in practical applications may include more or fewer components than described above, or combine certain components, or have different component arrangements. Since this embodiment employs all the technical solutions of the above-described motor heating method embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0216] Example 5

[0217] Based on the same inventive concept, referring to Figure 2The structural block diagram provided in this embodiment illustrates an electric vehicle, which may include:

[0218] Power battery;

[0219] Thermal management system;

[0220] Electric motor;

[0221] The motor controller is connected to the motor and is used to control the motor to operate in a stepless running mode to generate motor losses, which include copper losses and iron losses.

[0222] The thermal management system is connected to both the motor and the power battery, and is used to transfer the heat generated by the motor to the power battery to heat it.

[0223] Furthermore, electric vehicles may also include:

[0224] The main control system, connected to the motor controller, is used to generate motor heating commands and send them to the motor controller.

[0225] It needs to be explained that, Figure 2 The structure shown does not constitute a limitation on the electric vehicle of the present invention, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0226] Example 6

[0227] Based on the same inventive concept, this embodiment provides a computer-readable storage medium, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, disk, optical disk, server, etc. The storage medium stores a computer program, which can be executed by one or more processors. When the computer program is executed by the processor, it can implement all or part of the steps of the various embodiments of the motor heating method of the present invention.

[0228] It should be noted that the sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above embodiments are only optional embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made under the inventive concept of the present invention using the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are all included within the patent protection scope of the present invention.

Claims

1. A method for heating an electric motor, characterized in that, The method includes: Obtain the motor heating command; Based on the motor heating command and the pre-stored correspondence, the target high-frequency rotating current vector is obtained, and the target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency. According to the target high-frequency rotating current vector control motor, the motor operates in the out-of-step operation mode to generate motor losses. The heat generated by the motor losses is used to heat the power battery. The motor losses include copper losses and iron losses. The step of controlling the motor to operate in out-of-step mode based on the target high-frequency rotating current vector includes: The motor is controlled to operate in a rotational frequency growth mode. In this mode, the current amplitude of the high-frequency rotating current vector used to control the motor operation remains at zero, and the rotational frequency of the high-frequency rotating current vector used to control the motor operation gradually increases to the target rotational frequency. The motor is controlled to operate in a current amplitude growth mode. In the current amplitude growth mode, the rotation frequency of the high-frequency rotating current vector used to control the operation of the motor is kept at the target rotation frequency, and the current amplitude of the high-frequency rotating current vector used to control the operation of the motor is gradually increased to the target current amplitude. The motor is controlled by a high-frequency rotating current vector with the current amplitude being the target current amplitude and the rotation frequency being the target rotation frequency.

2. The motor heating method as described in claim 1, characterized in that, The step of obtaining the target high-frequency rotating current vector based on the motor heating command and the pre-stored correspondence includes: Based on the motor heating power extracted from the motor heating command, the target high-frequency rotating current vector is obtained by utilizing the pre-stored correspondence between the motor heating power and the high-frequency rotating current vector.

3. The motor heating method as described in claim 2, characterized in that, The step of obtaining the target high-frequency rotating current vector by extracting the motor heating power from the motor heating command and utilizing the pre-stored correspondence between the motor heating power and the high-frequency rotating current vector includes: Based on the motor heating power extracted from the motor heating command and the motor's NVH characteristics, the target current amplitude and the target rotation frequency are obtained by utilizing the pre-stored correspondence between motor heating power, current amplitude, and rotation frequency.

4. The motor heating method as described in claim 1, characterized in that, After controlling the motor to operate in a stepless mode based on the target high-frequency rotating current vector to generate motor losses, the method further includes: Obtain the motor heating stop command; The motor is controlled to exit the out-of-step operation mode according to the motor heating stop command.

5. The motor heating method as described in claim 1, characterized in that, The method further includes: The temperature of the motor is acquired while the motor is operating in the out-of-step mode; When the temperature of the motor reaches the over-temperature protection threshold, the target current amplitude of the target high-frequency rotating current vector is reduced, and the motor is controlled to operate in the out-of-step operation mode according to the adjusted target high-frequency rotating current vector.

6. The motor heating method as described in claim 4, characterized in that, The control of the motor to exit the out-of-step operation mode includes: The motor is controlled to operate in a current amplitude reduction mode. In the current amplitude reduction mode, the current amplitude of the high-frequency rotating current vector used to control the operation of the motor is gradually reduced to zero, and the rotation frequency of the high-frequency rotating current vector used to control the operation of the motor is maintained at the target rotation frequency. The motor is controlled to operate in a reduced rotation frequency mode. In this mode, the rotation frequency of the high-frequency rotating current vector used to control the motor operation is gradually reduced to zero, and the current amplitude of the high-frequency rotating current vector used to control the motor operation remains at zero.

7. The motor heating method as described in claim 1 or 6, characterized in that, The control of the motor operation includes: After determining the current amplitude and rotation frequency of the high-frequency rotating current vector used to control the motor operation, the command current is obtained; A voltage signal is obtained by PI regulation based on the command current and the feedback current of the motor. The voltage signal is subjected to space vector pulse width modulation to obtain a pulse width modulated signal; The inverter is controlled according to the pulse width modulation signal to drive the motor to operate at the current amplitude and the rotation frequency.

8. A motor heating device, characterized in that, The device includes: The instruction acquisition module is used to acquire motor heating instructions; The data acquisition module is used to obtain the target high-frequency rotating current vector according to the motor heating command and the pre-stored correspondence. The target high-frequency rotating current vector includes the target current amplitude and the target rotation frequency. The motor control module is used to control the motor to operate in a stepless operation mode according to the target high-frequency rotating current vector to generate motor losses, and to use the heat generated by the motor losses to heat the power battery. The motor losses include copper losses and iron losses. The motor control module includes a mode switching unit. The mode switching unit controls the motor operation in a frequency increase mode, where the amplitude of the high-frequency rotating current vector controlling the motor operation remains zero, and the rotation frequency of the high-frequency rotating current vector gradually increases to the target rotation frequency. Alternatively, the module can control the motor operation in a current amplitude increase mode, where the rotation frequency of the high-frequency rotating current vector controlling the motor operation remains at the target rotation frequency, and the amplitude of the high-frequency rotating current vector gradually increases to the target current amplitude. Finally, the module controls the motor operation using a high-frequency rotating current vector with the current amplitude equal to the target current amplitude and the rotation frequency equal to the target rotation frequency.

9. A motor controller, characterized in that, The motor controller includes a processor and a memory. The memory stores a motor heating program. When the motor heating program is executed by the processor, it implements the motor heating method as described in any one of claims 1 to 7.

10. An electric vehicle, characterized in that, include: Power battery; Thermal management system; Electric motor; The motor controller as described in claim 9 is connected to the motor and is used to control the motor to operate in a stepless operation mode to generate motor losses, the motor losses including copper losses and iron losses; The thermal management system is used to transfer the heat generated by the motor to the power battery to heat the power battery.

11. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by one or more processors, implements the motor heating method as described in any one of claims 1 to 7.

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