Motor heating control method, motor controller, assembly thereof and electric vehicle

Abstract

The application discloses a motor heating control method, a motor controller, an assembly of the motor controller and an electric vehicle. The motor heating control method comprises the following steps: obtaining a target heating power of a motor; determining motor control parameters in a plurality of heating periods according to the target heating power; and controlling the motor to operate according to the motor control parameters in the plurality of heating periods, so that the motor keeps a static state and the heat generated by each phase winding of the motor in each heating period is equal. The technical scheme can improve the heating efficiency of the star-connected asynchronous motor in the static state.

Description

Technical Field

[0001] This invention relates to the field of power battery heating technology, and in particular to a method for controlling motor heating, a motor controller and its assembly, and an electric vehicle. Background Technology

[0002] Currently, electric vehicles use electric motors to provide driving force, and in low-temperature environments, it is usually necessary to control the heating of the motor to improve the vehicle's operating performance.

[0003] In a scenario requiring motor heating, it's necessary to control the motor to generate heat while it's stationary, meaning the motor produces heat without outputting torque. Currently, both synchronous and asynchronous motors use a method of controlling the quadrature-axis current iq=0 to ensure zero output torque, while simultaneously applying a direct-axis current id to generate current, thus achieving heat generation without outputting torque.

[0004] However, this control method can lead to uneven temperature distribution in the three-phase windings of an asynchronous motor with a star connection. In order to ensure that the winding temperature does not exceed the set temperature value, the applied direct-axis current id can only be reduced, which limits the motor's heat dissipation power. Summary of the Invention

[0005] The main objective of this invention is to provide a method for controlling motor heating, which aims to solve the problem that the heating power of an asynchronous motor is limited by the uneven heating temperature of the three-phase windings.

[0006] To achieve the above objectives, the present invention proposes a motor heating control method, which includes: Obtain the target heating power of the motor; The motor control parameters for several heating cycles are determined based on the target heating power. The motor is controlled to operate according to the motor control parameters in the plurality of heating cycles, so that the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle.

[0007] Optionally, each heating cycle includes N heating stages, and the motor control parameters for each heating stage include duration and current vector parameters; The current vector parameters include the phase and magnitude of the current vector, where N is a positive integer.

[0008] Optionally, within one heating cycle, the motor control parameters for the N heating stages satisfy the following relationship: in, This represents the magnitude of the current vector in the nth heating stage. The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0009] Optionally, in one heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, and the motor control parameters for the N heating stages satisfy the following relationship: in, The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0010] Optionally, in one heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, the duration of each heating stage is equal, and the motor control parameters for the N heating stages satisfy the following relationship: in, This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0011] Optionally, in one heating cycle, the N current vectors corresponding to the N heating stages are divided into M basic sets, each of the basic sets including 3 current vectors, where M is a positive integer; In each of the fundamental sets, the phase of each current vector is... The phase difference between any two current vectors is 120° or 60°, and k is an integer greater than or equal to 0.

[0012] Optionally, controlling the motor operation according to the motor control parameters in the plurality of heating cycles includes: The motor is controlled to operate according to the duration and current vector parameters corresponding to each heating stage in each heating cycle; wherein, when the phase of the current vector of two adjacent heating stages is different, each heating stage is divided into two heating time periods, and the two adjacent heating stages are denoted as the j-th heating stage and the (j+1)-th heating stage, where j is a positive integer. During the second heating time period of the j-th heating stage, the amplitude of the current vector corresponding to the j-th heating stage is controlled to gradually decrease to a preset amplitude; the motor is controlled according to the phase of the current vector corresponding to the (j+1)-th heating stage, and at the same time, during the first heating time period of the (j+1)-th heating stage, the amplitude of the current vector is controlled to gradually increase from the preset amplitude to the amplitude of the current vector corresponding to the (j+1)-th heating stage.

[0013] Optionally, obtaining the target heating power of the motor includes: Obtain heating command; The target heating power of the motor is obtained according to the heating command.

[0014] The present invention also proposes a motor controller, the motor controller comprising: Memory; Processor; and, A motor heating control program stored in the memory and executable on the processor, wherein: when the motor heating control program is executed by the processor, it implements the motor heating control method as described above.

[0015] The present invention also proposes a motor controller assembly, which includes the motor controller described above.

[0016] The present invention also proposes an electric vehicle, the electric vehicle comprising a motor controller as described above; Alternatively, the electric vehicle may include a motor controller assembly as described above.

[0017] Optionally, the electric vehicle further includes: Thermal management system; The motor is electrically connected to the motor controller or the motor controller assembly. The power battery exchanges heat with the motor through the thermal management system.

[0018] The technical solution provided in this application obtains the target heating power of the motor; determines the motor control parameters for several heating cycles based on the target heating power; and controls the motor operation based on the motor control parameters for several heating cycles, so that the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle. The motor heating control method provided in this application eliminates the uneven temperature distribution of the three-phase windings during motor heating by ensuring that the heat generated by each phase winding of the motor is equal in each heating cycle, thereby increasing the maximum allowable current for the motor and enabling the motor to generate heat at a higher power, thus solving the problem of low heating efficiency in star-connected asynchronous motors. Attached Figure Description

[0019] 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 the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of current combination in an example technology; Figure 2 This is a flowchart illustrating the steps of a motor heating control method according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the vector distribution of four virtual vectors provided in an embodiment of the present invention; Figure 4 A schematic diagram showing the distribution of four current vectors and their virtual vectors according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the distribution of three current vectors and their virtual vectors according to an embodiment of the present invention; Figure 6 A schematic diagram showing the distribution of six current vectors and their virtual vectors according to an embodiment of the present invention; Figure 7 A schematic diagram showing the distribution of the eight basic sets provided in an embodiment of the present invention; Figure 8 for Figure 7 A schematic diagram of the distribution of current vectors corresponding to each heating stage, formed by basic set B and basic set G in the embodiment. Figure 9 This is a schematic diagram illustrating the effects of steps S300 and S400 in a motor heating control method provided in an embodiment of the present invention. Figure 10 This is a schematic flowchart of another step in the motor heating control method provided in an embodiment of the present invention; Figure 11 A schematic diagram of the hardware operating environment of a motor controller provided in an embodiment of the present invention; Figure 12 This is a schematic diagram of an electric vehicle module provided according to an embodiment of the present invention.

[0021] Explanation of icon numbers: 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

[0022] The technical solutions of the embodiments of the present 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 the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Furthermore, in this invention, descriptions involving "first," "second," etc., 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, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0024] This invention proposes a method for controlling motor heating.

[0025] In one example technology, the formula for the output torque of an asynchronous motor is: Where Te is the motor output torque, Pn is the number of pole pairs, Lm is the motor mutual inductance, id is the direct-axis current, and iq is the quadrature-axis current. From the output torque formula of an asynchronous motor, it can be seen that when... At that time, the motor output torque is zero.

[0026] By controlling the quadrature-axis current of the motor to zero while applying the direct-axis current, the motor generates heat without outputting torque, thus achieving heat generation in a stationary state. In the stationary state, the rotor speed of the motor is zero (i.e., rotor speed wr=0).

[0027] Formula for steady-state slip of an asynchronous motor: Rr is the resistance of the motor stator winding.

[0028] From the formula for the steady-state slip of an asynchronous motor, it can be seen that when the quadrature-axis current is zero ( In the motor heating control scheme, the slip frequency ωs is also zero, so the electrical frequency we=wr+ws=0. At this time, the electrical frequency of the three-phase current is 0, which is DC.

[0029] For a star-connected three-phase motor, there is a principle that the sum of the three-phase currents is zero, i.e., ia + ib + ic = 0. When ia, ib, and ic are DC currents, their amplitudes must be unequal; otherwise, ia = ib = ic = 0. If the DC currents of each phase are the same, then the DC currents of each phase must be zero. However, in this case, the motor cannot generate heat, leading to uneven temperature distribution in the three-phase windings when the motor heats up. Considering the "weakest link" effect, the maximum allowable current of the motor must be less than the maximum allowable current when the three-phase winding temperature is evenly distributed. Therefore, the motor's heat generation power is limited.

[0030] From the formula for the steady-state slip of an asynchronous motor, it can be seen that when the slip ws = 0, there must be... When the motor is stationary, i.e., wr=0, as long as the electrical frequency is 0, the slip ws=we-wr=0-0=0. In other words, when the motor is stationary, as long as three-phase DC power is applied, the steady-state output torque can be guaranteed to be 0.

[0031] However, for the same heating power, the magnitude of the current vector is constant, but the components ia, ib, and ic of the current vector in the three-phase current can have different combinations; for example, for a current vector of is = 150A, it includes at least the following three combinations of three-phase currents: iabc0=(ia0,ib0,ic0)=(100A,-50A,-50A), iabc1=(ia1,ib1,ic1)=(-50A,100A,-50A), iabc2=(ia2,ib2,ic2)=(-50A,-50A,100A).

[0032] When using In the control mode, for a given direct-axis current id, when the magnetic field orientation angle... When the current is fixed, only one fixed combination of currents can be obtained, and the expression for this combination of currents is as follows: .

[0033] As can be seen from the above, when the magnetic field orientation angle When the angle is 0°, the corresponding current combination is iabc0; when the magnetic field orientation angle is... When the angle is 120°, the corresponding current combination is iabc1; magnetic field orientation angle When the angle is 240°, the corresponding current combination is iabc2; the phase relationship of the aforementioned current combinations iabc0, iabc1, and iabc2 is as follows: Figure 1 As shown.

[0034] Of course, the above-mentioned exemplary technology achieves phase adjustment of the current vector by controlling the orientation angle of the magnetic field. In practical applications, there are also various motor control methods for adjusting the phase of the current vector, such as controlling the single-phase voltage. These will not be described in detail here.

[0035] However, since all methods for controlling the heating of motors in a static state employ... Therefore, uneven temperature distribution in the three-phase windings is present in all of them.

[0036] In response to the above problems, refer to Figure 2 This application provides a method for controlling motor heating, which includes the following steps: Step S100: Obtain the target heating power of the motor.

[0037] Step S200: Determine the motor control parameters for several heating cycles based on the target heating power.

[0038] The number of heating cycles of an electric motor can be one or more.

[0039] The implementing entity of the technical solution in this application can be a motor controller.

[0040] Optionally, the number of heating cycles may be one or more. The number of heating cycles is determined based on the actual situation, and this application embodiment does not limit this.

[0041] When there is one heating cycle, the motor controller can call the corresponding preset motor control parameters or calculate and generate the corresponding real-time motor control parameters according to the target heating power to serve as the motor control parameters in that heating cycle.

[0042] When there are multiple heating cycles (more than one), the motor controller can call multiple preset motor control parameters or calculate and generate multiple real-time motor control parameters at once, which will be used as the motor control parameters in each heating cycle. Alternatively, it can first call a first preset number of preset motor control parameters or calculate and generate a first preset number of real-time motor control parameters, which will be used as the motor control parameters in the first preset number of heating cycles. After the first preset number of heating cycles are completed, it will call a second preset number of preset motor control parameters or calculate and generate a second preset number of real-time motor control parameters, which will be used as the motor control parameters in the second preset number of heating cycles, and so on, until all heating cycles are completed. The number of motor control parameters called or calculated each time may be the same or different, which is not limited here.

[0043] Step S300: Control the motor operation according to the motor control parameters in several heating cycles, so that the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle.

[0044] Optionally, the motor controller can generate and output multiple PWM signals with corresponding duty cycles to the inverter in the corresponding heating cycle according to the acquired motor control parameters, so that the inverter can output the corresponding three-phase voltage to the three-phase input terminal of the motor according to the received multiple PWM signals, so that three-phase current can be generated in the three-phase winding of the motor.

[0045] During each heating cycle, the motor is controlled to operate according to the motor control parameters corresponding to the heating cycle. The motor remains stationary, and the heat generated by each phase winding of the motor is equal in each heating cycle. That is, in each heating cycle, the heat generated by the U-phase winding is equal to the heat generated by the V-phase winding and the heat generated by the W-phase winding.

[0046] Optionally, when there are multiple heating cycles, there are several cyclic heating cycles within the multiple heating cycles, and each cyclic heating cycle may include a preset number of heating cycles; or, when there are multiple heating cycles, there are no cyclic heating cycles within the multiple heating cycles.

[0047] For example, there are 10 heating cycles, which are T1, T2, T3, T4, T5, T6, T7, T8, T9, and T10. The motor control parameters are different in each heating cycle. In this case, there is no cyclic heating cycle among the 10 heating cycles.

[0048] Alternatively, for example: there are 4 heating cycles, which are composed of T1, T1, T1, T1. In this case, there are 4 cyclic heating cycles, and each cyclic heating cycle includes 1 heating cycle.

[0049] Alternatively, for example: there are a total of 8 heating cycles, which are composed of T1, T2, T3, T4, T1, T2, T3, T4. Among these 8 heating cycles, there are 2 cyclic heating cycles, namely T1, T2, T3, T4. Each cyclic heating cycle includes 4 heating cycles, and the motor control parameters in heating cycles T1, T2, T3, and T4 are different.

[0050] Alternatively, for example: there are 10 heating cycles, which are composed of T1, T2, T3, T1, T2, T3, T4, T5, T6, and T7. Among these 10 heating cycles, there are 2 cyclic heating cycles, namely T1, T2, and T3. Each cyclic heating cycle includes 3 heating cycles. The motor control parameters in heating cycles T1, T2, T3, T4, T5, T6, and T7 are different.

[0051] Since the heat generated by the three-phase windings is equal in each heating cycle, that is, the heat generated by the U phase is equal to the heat generated by the V phase and the heat generated by the W phase, the phenomenon of uneven temperature distribution of the three-phase windings is eliminated, the maximum current allowed to be passed into the motor is increased, and the motor can generate heat with higher power, thereby solving the problem of low heating efficiency caused by the limitation of the heating efficiency of asynchronous motors.

[0052] Based on Figure 2 In an optional embodiment of the illustrated example, each heating cycle includes N heating stages, and the motor control parameters for each heating stage include duration and current vector parameters; The current vector parameters include the phase and magnitude of the current vector, where N is a positive integer.

[0053] based on Figure 2In an optional embodiment of the illustrated example, step S200 can be implemented by step S200', and step S300 can be implemented by step S30': Step S200': Determine the duration of each heating stage in several heating cycles and the current vector parameters corresponding to each heating stage based on the target heating power. Step S300': Based on the duration of each heating stage in several heating cycles and the current vector parameters corresponding to each heating stage, output a three-phase current corresponding to the current vector parameters of that heating stage to the motor during the duration of each heating stage, so that the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle.

[0054] In an optional embodiment of the above embodiments, within one heating cycle, the motor control parameters for N heating stages satisfy the following formulas 1 and 2: Formula 1 is: ; Formula 2 is: ; in, This represents the magnitude of the current vector in the nth heating stage. The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0055] Optionally, the duration of each heating stage is measured in advance through multiple experiments and stored in the motor controller so that the motor controller can retrieve it after entering the motor heating control mode.

[0056] It should be noted that the order in which the motor control parameters of the N heating stages in a heating cycle are executed can be determined according to the actual situation. For example, they can be executed sequentially in the order of 1 to N, or not in the order of 1 to N. As long as the motor control parameters of the N heating stages are all executed, it is acceptable. The order of the first heating stage, the second heating stage, ..., the Nth heating stage in the embodiments of this application is only an example and is not limited in this respect.

[0057] Here, we take the motor control parameters for N heating stages (Step1~StepN) in one heating cycle as an example to further illustrate the solution of this application: Step 1 of the first heating stage: The three-phase current corresponding to the output current vector 1, the amplitude of the current vector 1 is1, the phase is θ1, and the duration of Step 1 of the first heating stage is t1. Step 2, the second heating stage: output current vector 2 corresponds to the three-phase current, the amplitude of current vector 2 is2, the phase is θ2, and the duration of Step 2, the second heating stage is t2. ...and so on; Step N, the Nth heating stage: the three-phase current corresponding to the output current vector N, the amplitude of the current vector N isN, the phase θN, and the duration of Step N, the Nth heating stage. Within one heating cycle T, the heat generation Pa, Pb, and Pc of the three-phase windings are expressed by the following formula: When the heat generated by the three-phase windings is equal in each heating cycle, there is By simplification, we obtain Formula 3 and Formula 4 as shown below: Formula 3 is: ; Formula four is: ; Therefore, within a heating cycle, if the duration of each heating stage, the amplitude and phase of the current vector corresponding to the three-phase current output in each heating stage satisfy the above formulas 1 and 2, then the heat generated by the three-phase windings within a heating cycle will be equal. See attached details. Figure 3 As shown, when N=4, there are 4 virtual vectors corresponding to the 4 current vectors; the magnitudes of the 4 virtual vectors are respectively , , , The phases are respectively , , , Under the premise of satisfying Formulas 3 and 4, the vector sum of the four virtual vectors is zero.

[0058] Taking a heating cycle consisting of four heating stages as an example, the following example illustrates the values ​​when the duration of each heating stage, the amplitude of the corresponding current vector, and the phase of each heating stage are not equal. For details, please refer to [reference needed]. Figure 4 : Step 1 of the first heating stage: The amplitude of the current vector 1 corresponding to the three-phase current is 100A and the phase is 0°. The duration of Step 1 of the first heating stage is 100s. Step 2, the second heating stage: the amplitude of the current vector 2 corresponding to the three-phase current is 141.42A, the phase is 45°, and the duration of Step 2 is 50s. Step 3, the third heating stage: the amplitude of the current vector 3 corresponding to the three-phase current is 70.72A, the phase is 90°, and the duration of Step 3 is 200s. Step 4, the fourth heating stage: the amplitude of the current vector 4 corresponding to the three-phase current is 50A, the phase is 135°, and the duration of Step 4 is 400s.

[0059] Depend on Figure 4 It can be seen that although the duration of the four heating stages, the amplitude and phase of the corresponding current vectors in each heating stage are not equal, the vector sum of the four virtual vectors is still zero. Therefore, the combination of the four current vectors can ensure that the heat generated by the three-phase windings is equal in this heating cycle, that is, the heating of the three-phase windings is uniform in this heating cycle.

[0060] In an optional embodiment of the above embodiments, in one heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, and the motor control parameters for N heating stages satisfy the following formulas five and six: Formula 5 is: ; Formula six is: ; in, The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0061] By ensuring that the magnitudes of the current vectors corresponding to each heating stage within a heating cycle are equal, i.e., is1= is2=…=isN, the motor control parameters for the N heating stages within a heating cycle satisfy formulas five and six, thus guaranteeing that the motor's heating power remains constant throughout the heating process.

[0062] Taking a heating cycle consisting of three heating stages as an example, the amplitude of the current vector corresponding to each heating stage in this heating cycle is equal, while the duration of each heating stage and the phase of the corresponding current vector are different. The following example illustrates this; please refer to the details. Figure 5 : Step 1: The amplitude of current vector 1 corresponding to the three-phase current is 100A, the phase is 0°, and the duration of the first heating stage is 100s. Step 2, the second heating stage: the amplitude of the current vector 2 corresponding to the three-phase current is 100A, the phase is 45°, and the duration of the second heating stage is 173.2s. Step 3: The current vector 3 corresponding to the three-phase current has an amplitude of 100A and a phase of 120°. The duration of the third heating stage is 200s.

[0063] Depend on Figure 5 It can be seen that although the amplitude of the current vector corresponding to each heating stage in the heating cycle is equal, the duration of each heating stage and the phase of the corresponding current vector are different, the vector sum of the three virtual vectors corresponding to the three current vectors is still zero. Therefore, the combination of the above three current vectors can still ensure that the heat generation of the three-phase windings is equal in the heating cycle, that is, the heating of the three-phase windings is uniform in the heating cycle.

[0064] In an optional embodiment, within a heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, and the duration corresponding to each heating stage is equal. The motor control parameters for the N heating stages satisfy the following formulas seven and eight: Formula 7 is: ; Formula 8 is: ; in, This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

[0065] If, during the heating process, not only is it required that the amplitude of the current vector remain constant, but also that the duration of each current vector is the same, i.e., t1 = t2 = ... = tN and t1 = t2 = ... = tN, then the motor control parameters for N heating stages in one heating cycle, where the heat generated by the three-phase windings is equal, must satisfy the above formulas seven and eight.

[0066] Taking a heating cycle consisting of 6 heating stages as an example, the duration and corresponding current vector amplitude of each heating stage in this heating cycle are equal. The values ​​of the current vectors corresponding to different heating stages are shown in the following example. For details, please refer to... Figure 6 : Step 1 of the first heating stage: The amplitude of the current vector 1 corresponding to the three-phase current is 100A and the phase is 0°. The duration of Step 1 of the first heating stage is 100s. Step 2 of the second heating stage: The amplitude of the current vector 2 corresponding to the three-phase current is 100A and the phase is 120°. The duration of Step 2 of the second heating stage is 100s. Step 3, the third heating stage: the current vector 3 corresponding to the three-phase current has an amplitude of 100A and a phase of 240°. The duration of Step 3, the third heating stage, is 100s. Step 4, the fourth heating stage: the current vector 4 corresponding to the three-phase current has an amplitude of 100A and a phase of 210°. The duration of Step 4, the fourth heating stage, is 100s. Step 5, the fifth heating stage: The current vector 5 corresponding to the three-phase current has an amplitude of 100A and a phase of 90°. The duration of Step 5, the fifth heating stage, is 100s. Step 6, the sixth heating stage: The current vector 6 corresponding to the three-phase current has an amplitude of 100A and a phase of 330°. The duration of Step 6, the sixth heating stage, is 100s.

[0067] Depend on Figure 6 It can be seen that although the duration of each heating stage and the amplitude of the corresponding current vector are equal in this heating cycle, and the phase of the current vector corresponding to each heating stage is different, the vector sum of the six virtual vectors is still zero. Therefore, the combination of the above six current vectors can ensure that the heat generation of the three-phase winding is equal in this heating cycle, that is, the heating of the three-phase winding is uniform in this heating cycle.

[0068] When it is required that the amplitude and duration of each current vector remain unchanged during the heating process, and the absolute value of the three-phase DC current is minimized to reduce the current stress on the inverter, the motor control parameters corresponding to the N heating stages in a heating cycle not only satisfy the above formulas five and six, but also satisfy the following relationship: in a heating cycle, the N current vectors corresponding to the N heating stages are divided into M basic sets, each basic set includes 3 current vectors, and M is a positive integer; In each fundamental set, the phase of each current vector is... Any two current vectors are 120° or 60° out of phase. It is an integer greater than or equal to 0.

[0069] In practical applications, when the duration and corresponding current vector magnitudes of each heating stage in a heating cycle are equal (is1 = is2 = ... = isN and t1 = t2 = ... = tN), but the phases of the current vectors corresponding to each heating stage are different, there is a problem that although the heating of the three-phase windings can be made uniform during the heating cycle, the current stress on the inverter is relatively large. To address this problem, since it is necessary to minimize the absolute value of the three-phase DC current, it is necessary to satisfy Formula Nine: Formula Nine is: According to Formula 9, the range of phase values ​​for the current vector can be obtained as follows: .

[0070] Furthermore, the N current vectors corresponding to the N heating stages in the same heating cycle can be divided into M basic sets, each basic set including three current vectors; in each basic set, the phase of each current vector satisfies Formula 10, the amplitude of each current vector is equal, and the phase difference between any two adjacent current vectors is 120° or 60°; where Formula 10 is: k is a positive integer greater than or equal to 0.

[0071] As can be seen from the above, there are 8 forms of the fundamental set, and the phase distribution diagram of the fundamental set is as follows: Figure 7 As shown in (A) to (H). The phases of the three current vectors in the eight basic sets are explained below in a counterclockwise direction. Basic set A: 330° (-30°), 30°, 90°; Basic set B: 270° (-90°), 330° (-30°), 30°; Basic set C: 210°, 270°, 330°; Basic set D: 90°, 210°, 330°; Basic set E: 150°, 210°, 270°; Basic set F: 90°, 150°, 210°; Basic set G: 30°, 90°, 150°; Basic set H: 30°, 150°, 270°.

[0072] Thus, when the duration of each heating stage within a heating cycle is equal, the amplitude of each current vector is equal, and all current vectors in the heating cycle are decomposed into M fundamental sets, each fundamental set consisting of three current vectors, and the phase of each current vector satisfies... When the phase difference between any two adjacent current vectors is 120° or 60°, the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle, while ensuring that the current stress of the inverter is minimized.

[0073] A heating cycle consists of six heating stages. The duration and magnitude of the corresponding current vectors in each heating stage are equal. All current vectors in the heating cycle are decomposed into two fundamental sets, each consisting of three current vectors. The phases of each current vector satisfy the following condition: For example, when the phase difference between any two adjacent current vectors is 120° or 60°, please refer to [the relevant documentation]. Figure 8 : Step 1: The amplitude of the current vector 1 corresponding to the three-phase current is 100A, the phase is 30°, and the duration of the first heating stage is 100s. Step 2: The amplitude of the current vector 2 corresponding to the three-phase current is 100A, the phase is 90°, and the duration of the second heating stage is 100s. Step 3: The current vector 3 corresponding to the three-phase current has an amplitude of 100A and a phase of 150°. The duration of the third heating stage is 100s. Step 4: The amplitude of the current vector 4 corresponding to the three-phase current is 100A, the phase is 330°, and the duration of the fourth heating stage is 100s. Step 5: The amplitude of the current vector 5 corresponding to the three-phase current is 100A, the phase is 30°, and the duration of the fifth heating stage is 100s. Step 6: The current vector 6 corresponding to the three-phase current has an amplitude of 100A and a phase of 270°. The duration of Step 6 is 100s.

[0074] It should be noted that when there are multiple heating cycles, the relationship between the motor control parameters in each heating cycle is determined according to the actual situation. All heating cycles may have the same motor control parameter relationship, or multiple heating cycles may have several different motor control parameter relationships. The relationships of the selectable motor control parameters are as shown above, and will not be repeated here.

[0075] In practical applications, during the actual control of motor heating, there are instances where the phases of the current vectors corresponding to two adjacent heating stages are not equal. This situation can be called a phase abrupt change in the current vector. When the phase of the current vector changes abruptly, i.e. during the switching between two heating stages, a transient torque is generated in the motor, causing motor vibration.

[0076] To avoid motor vibration during the heating process, in an optional embodiment of the above embodiments, step S300, namely "controlling motor operation according to motor control parameters in several heating cycles", can be implemented by the following steps: S301. Control the motor operation according to the duration and current vector parameters corresponding to each heating stage in each heating cycle.

[0077] It should be noted that two adjacent heat-generating stages can belong to the same heat-generating cycle or to different heat-generating cycles (i.e., the j-th heat-generating stage and the (j+1)-th heat-generating stage are located in two adjacent heat-generating cycles respectively). In terms of execution order, two adjacent heat-generating stages are sequential.

[0078] When the phases of the current vectors corresponding to two adjacent heating stages are different, control the motor operation according to the following steps: Step S3011: When the phases of the current vectors of two adjacent heating stages are different, each heating stage is divided into two heating time periods. The two adjacent heating stages are denoted as the j-th heating stage and the (j+1)-th heating stage, where j is a positive integer.

[0079] The duration of each heating period in each heating phase is determined according to the actual situation. The durations of the two heating periods constituting a heating phase can be equal or unequal. The sum of the durations of the two heating periods is the duration corresponding to that heating phase in the motor control parameters.

[0080] Step S3012: During the second heating time period of the j-th heating stage, control the amplitude of the current vector corresponding to the j-th heating stage to gradually decrease to the preset amplitude.

[0081] Optionally, during the second heating time period of the j-th heating stage, before the amplitude of the current vector corresponding to the j-th heating stage decreases to a preset amplitude, there is a time during which the motor runs according to the amplitude of the current vector corresponding to the j-th heating stage; during the first heating time period of the j-th heating stage, there is also a time during which the motor runs according to the amplitude of the current vector corresponding to the j-th heating stage.

[0082] Step S3013: Control the motor according to the phase of the current vector corresponding to the (j+1)th heating stage, and at the same time, during the first heating time period of the (j+1)th heating stage, control the amplitude of the current vector to gradually increase from the preset amplitude to the amplitude of the current vector corresponding to the (j+1)th heating stage.

[0083] When the current amplitude decreases to the preset amplitude, the motor is controlled according to the phase of the current vector corresponding to the (j+1)th heating stage. At the same time, the amplitude of the current vector is controlled to gradually increase from the preset amplitude to the amplitude of the current vector corresponding to the (j+1)th heating stage during the first heating time period of the (j+1)th heating stage.

[0084] Optionally, during the first heating time period of the (j+1)th heating stage, after the amplitude of the current vector increases from the preset amplitude to the amplitude of the current vector corresponding to the (j+1)th heating stage, there is a time when the motor is controlled to run according to the amplitude of the current vector corresponding to the (j+1)th heating stage; during the second heating time period of the (j+1)th heating stage, there is also a time when the motor is controlled to run according to the amplitude of the current vector corresponding to the (j+1)th heating stage.

[0085] Optionally, in the j-th heating stage and the (j+1)-th heating stage, the rate of decrease of the current vector amplitude is the same as the rate of increase of the current vector amplitude.

[0086] Optionally, the preset amplitude is 0, or the preset amplitude is a small positive value pre-calibrated according to the actual situation.

[0087] When the phases of the current vectors in two adjacent heating stages are different, the amplitude is first reduced to a preset amplitude (e.g., a minimum value), then the phase of the current vector is changed, and then the amplitude of the current vector is increased from the preset amplitude to the amplitude corresponding to the heating stage. This ensures that no torque fluctuation occurs when the phases of the two heating stages switch. Reducing the current amplitude to a minimum value ensures that the phase change at that current amplitude will not cause motor vibration.

[0088] When the motor heating method provided in this application is applied to an electric vehicle, and the heat from the motor is used to heat the power battery, it helps to improve the user's riding comfort when the motor is stationary and heating up.

[0089] In one example, such as Figure 9 As shown, a heating cycle T includes 6 heating stages, and the phases of the current vectors in each heating stage of heating cycle T are as follows: , , , , , When the motor is controlled according to the motor control parameters corresponding to the six heating stages in the heating cycle T, the timing of the current vector amplitude and phase adjustment is as follows: Figure 9 As shown.

[0090] Reference Figure 10 In an optional embodiment of the above embodiments, step S100, namely "obtaining the target heating power of the motor", can be implemented by the following steps: Step S110: Obtain the heating command.

[0091] Step S120: Obtain the target heating power of the motor according to the heating command.

[0092] In this embodiment, the motor controller can communicate with the main control unit in the device where the motor is located. When it is determined that the motor needs to heat up while stationary, the main control unit can determine the target temperature and heating strategy for the motor's stationary heating, and can generate a heating command based on the determined target temperature and heating strategy and output it to the motor controller. This allows the motor controller to call the corresponding preset heating power or calculate and generate a real-time heating power as the target heating power for the motor based on the heating command.

[0093] The heat generated by the motor can be used to heat components in the device where the motor is located. For example, the motor heating control method provided in this application can be used in electric vehicles. When the power battery in the electric vehicle needs to be heated, the motor heating is controlled according to the motor heating control method provided in this application, and the heat generated by the motor is used to heat the power battery.

[0094] This application also proposes a motor controller.

[0095] Reference Figure 11 In one embodiment, the motor controller includes: Memory 11; Processor 12; and, A motor heating control program stored in memory 11 and executable on processor 12, wherein the motor heating control program, when executed by processor 12, implements the motor heating control method as described above.

[0096] The specific steps of the motor heating control method are as described in the above embodiments. Since this motor controller adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be repeated here. The memory 11 can be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk storage device. The memory 11 can also be a storage device independent of the aforementioned control device. The processor 12 can be a CPU. The memory 11 and the processor 12 are connected by a communication bus 13, which can be a UART bus or an I2C bus.

[0097] This application also proposes a motor controller assembly, which includes a motor controller. The specific structure of the motor controller is as described in the above embodiments. Since this motor controller assembly adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0098] The present invention also proposes an electric vehicle, with reference to Figure 12 The electric vehicle includes a motor controller 10 or a motor controller assembly. The specific structure of the motor controller 10 or the motor controller assembly is as described in the above embodiments. Since this electric vehicle adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0099] In one embodiment, the electric vehicle further includes: Thermal management system 20; Motor 30 is electrically connected to motor controller 10 or motor controller assembly; The power battery 40 exchanges heat with the motor 30 through the thermal management system 20.

[0100] In this embodiment, the motor 30 can be an asynchronous motor with a star-connected winding; the thermal management system 20 can include heat exchange pipes or heat exchange components. When running the motor heating control program, the motor controller 10 or the motor controller assembly can output a three-phase AC current corresponding to the motor control parameters of each heating cycle to the motor 30 via an integrated inverter in each heating cycle, so that while the motor 30 remains stationary, each phase winding can generate equal heat in each heating cycle. Thus, since the heat generated by each phase winding in each heating cycle can be transferred to the power battery 40 through the thermal management system 20, the power battery 40 can be heated while the electric vehicle is parked. Furthermore, since the technical solution provided in the application embodiment allows the motor 30 to heat with higher power, the heating efficiency of the motor 30 on the power battery 40 can be effectively improved.

[0101] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of this application. Any equivalent structural transformations made using the contents of the specification and drawings of this application under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for controlling motor heating, characterized in that, The method includes: Obtain the target heating power of the motor; The motor control parameters for several heating cycles are determined based on the target heating power. The motor is controlled to operate according to the motor control parameters in the plurality of heating cycles, so that the motor remains stationary and the heat generated by each phase winding of the motor is equal in each heating cycle. Each heating cycle includes N heating stages, and the motor control parameters for each heating stage include duration and current vector parameters. The current vector parameters include the phase and magnitude of the current vector, where N is a positive integer; Within one heating cycle, the motor control parameters for the N heating stages satisfy the following relationship: in, This represents the magnitude of the current vector in the nth heating stage. The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

2. The method according to claim 1, characterized in that, In one heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, and the motor control parameters for the N heating stages satisfy the following relationship: in, The duration of the nth heating phase. This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

3. The method according to claim 1, characterized in that, In one heating cycle, the magnitude of the current vector corresponding to each heating stage is equal, the duration of each heating stage is equal, and the motor control parameters for N heating stages satisfy the following relationship: in, This represents the phase of the current vector in the nth heating stage, where n ranges from 1 to N and is a positive integer.

4. The method according to claim 3, characterized in that, In one heating cycle, the N current vectors corresponding to the N heating stages are divided into M basic sets, each of which includes 3 current vectors, where M is a positive integer; In each of the fundamental sets, the phase of each of the current vectors is The phase difference between any two current vectors is 120° or 60°, and k is an integer greater than or equal to 0.

5. The method according to claim 1, characterized in that, Controlling the motor operation according to the motor control parameters in the aforementioned heating cycles includes: The motor is controlled to operate according to the duration and current vector parameters corresponding to each heating stage in each heating cycle; wherein, when the phase of the current vector of two adjacent heating stages is different, each heating stage is divided into two heating time periods, and the two adjacent heating stages are denoted as the j-th heating stage and the (j+1)-th heating stage, where j is a positive integer. During the second heating time period of the j-th heating stage, the amplitude of the current vector corresponding to the j-th heating stage is controlled to gradually decrease to a preset amplitude; the motor is controlled according to the phase of the current vector corresponding to the (j+1)-th heating stage, and at the same time, during the first heating time period of the (j+1)-th heating stage, the amplitude of the current vector is controlled to gradually increase from the preset amplitude to the amplitude of the current vector corresponding to the (j+1)-th heating stage.

6. The method according to any one of claims 1-5, characterized in that, The acquisition of the target heating power of the motor includes: Obtain heating command; The target heating power of the motor is obtained according to the heating command.

7. A motor controller, characterized in that, The motor controller includes: Memory; Processor; and, A motor heating control program stored in the memory and executable on the processor, wherein: when the motor heating control program is executed by the processor, it implements the motor heating control method as described in any one of claims 1 to 6.

8. A motor controller assembly, characterized in that, The motor controller assembly includes the motor controller as described in claim 7.

9. An electric vehicle, characterized in that, The electric vehicle includes the motor controller as described in claim 7; Alternatively, the electric vehicle may include the motor controller assembly as described in claim 8.

10. The electric vehicle according to claim 9, characterized in that, The electric vehicle also includes: Thermal management system; The motor is electrically connected to the motor controller or the motor controller assembly. The power battery exchanges heat with the motor through the thermal management system.

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