Torque control method and device of permanent magnet motor

Abstract

The invention relates to the technical field of motor control, in particular to a torque control method and device of a permanent magnet motor, and the method comprises the steps: obtaining real-time stator winding voltage and real-time stator winding current in the permanent magnet motor; determining a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current; based on the real-time flux linkage and a target torque of the permanent magnet motor, determining a target total current required by the target torque; determining a target torque instruction for controlling the output of the permanent magnet motor based on the target total current and a preset corresponding relation table; wherein the preset corresponding relation table is used for representing the corresponding relation between the current and the torque instruction. According to the method, the target torque instruction capable of controlling the output of the permanent magnet motor is accurately calculated by estimating the real-time flux linkage, so that the influence of temperature rise on the output torque is overcome, and the accuracy is relatively high.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a torque control method and device for a permanent magnet motor in the technical field of motor control. Background Art

[0002] Automotive motors are usually required to have higher torque control accuracy. However, for permanent magnet motors, after running for a period of time, the magnetic force value of the permanent magnet changes due to changes in the internal temperature of the motor; ultimately, the output torque of the motor changes accordingly, resulting in a deterioration in torque control accuracy. Summary of the invention

[0003] The object of the present invention is to provide a method and device for controlling the torque of a permanent magnet motor. The technical solution adopted is as follows:

[0004] In a first aspect, an embodiment of the present invention provides a method for controlling torque of a permanent magnet motor, the method comprising:

[0005] Obtaining real-time stator winding voltage and real-time stator winding current in a permanent magnet motor;

[0006] Determining a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current;

[0007] Determining a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor;

[0008] Based on the target total current and a preset correspondence table, a target torque instruction for controlling the output of the permanent magnet motor is determined; wherein the preset correspondence table is used to characterize the correspondence between the current and the torque instruction.

[0009] In a second aspect, an embodiment of the present invention provides a torque control device for a permanent magnet motor, the device comprising:

[0010] An acquisition module, used for acquiring real-time stator winding voltage and real-time stator winding current in the permanent magnet motor;

[0011] A first determination module, configured to determine a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current;

[0012] A second determination module is used to determine a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor;

[0013] The third determination module is used to determine the target torque instruction for controlling the output of the permanent magnet motor based on the target total current and a preset correspondence table; wherein the preset correspondence table is used to characterize the correspondence between current and torque instructions.

[0014] According to a third aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first aspect or any possible implementation of the first aspect.

[0015] In a fourth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the method in the first aspect or any possible implementation manner described in the first aspect.

[0016] The present invention has the following beneficial effects:

[0017] 1. By obtaining the real-time stator winding voltage and the real-time stator winding current in the permanent magnet motor, the real-time stator winding voltage and the real-time stator winding current can be input into the calculation formula of the magnetic flux, so as to accurately and in real time calculate the real-time magnetic flux of the motor; in this way, the magnetic flux of the permanent magnet motor is estimated online, so that the real-time performance and accuracy are better; the target total current required for the target torque is determined by the real-time magnetic flux and the target torque of the permanent magnet motor; in this way, after the real-time magnetic flux is calculated, since the target torque of the permanent magnet motor and the calculation formula of the target torque are known, the target total current required for the target torque can be accurately calculated by substituting the real-time magnetic flux and the target torque into the calculation formula of the target torque; the target torque instruction for controlling the permanent magnet motor to output the target torque is determined by the target total current and the preset correspondence table; wherein the preset correspondence table is used to characterize the correspondence between current and torque instructions. In this way, after the target total current that meets the target torque is calculated through the real-time magnetic flux and the target torque of the permanent magnet motor, since the correspondence between the current and the torque command is stored in the preset relationship table, the target torque command of the permanent magnet motor can be quickly obtained by searching the preset relationship table according to the target total current, so that the permanent magnet motor can output the required target torque under the target torque command, thereby overcoming the influence of temperature increase on the output torque of the permanent magnet motor and improving the accuracy of the output target torque.

[0018] 2. The target torque command is obtained by searching for the torque command that matches the target total current in the preset correspondence table; and the torque command that matches the target total current is limited. In this way, the target torque command can be obtained more accurately by obtaining the torque command that matches the target total current through the preset correspondence table and limiting the torque command.

[0019] 3. After obtaining the preset limit range, the torque command matching the target total current is adjusted according to the preset limit range to obtain the target torque command; in this way, by adjusting the limit of the torque command matching the target total current, the obtained target torque command can accurately control the permanent magnet motor to output the target torque.

[0020] 4. After obtaining the q-axis real-time stator winding voltage, q-axis real-time stator winding voltage and d-axis real-time stator winding current of the stator winding in the permanent magnet motor, the q-axis real-time stator winding voltage and the q-axis real-time stator winding voltage are determined as the real-time stator winding voltage, and the d-axis real-time stator winding current is determined as the real-time stator winding current; in this way, the real-time voltage of the stator winding of the permanent magnet motor and the real-time currents of the q-axis and d-axis are obtained in real time through the controller, thereby facilitating the real-time calculation of the magnetic flux of the motor.

[0021] 5. First, obtain the total current corresponding to the given torque command, as well as the given current of the stator winding of the permanent magnet motor in the q-axis and d-axis; then, calculate the current angle between the q-axis and the d-axis through the total current and the given current of the q-axis and the d-axis; in this way, the current angle between the q-axis and the d-axis can be quickly calculated; finally, calculate the target total current required for the target torque through the current angle, the real-time flux linkage and the target torque of the permanent magnet motor. In this way, by combining the current angle, the real-time flux linkage and the target torque of the permanent magnet motor, the target total current required for the target torque can be accurately calculated.

[0022] 6. The stator winding current required for the target torque is calculated by the real-time flux and the target torque of the permanent magnet motor. Here, after the real-time flux is calculated, the stator winding current required for the target matrix can be accurately calculated by combining the target torque; finally, the target total current can be calculated by the stator winding current required for the target torque and the current angle; wherein the stator winding current required for the target torque and the target total current satisfy the formula: I q ′=I*cosθ and I d ′=I*sinθ; where, I d ′,I q ′ respectively represent the stator winding current required for the target torque, I represents the target total current, and θ represents the current angle. In this way, after the stator winding current required for the target torque is calculated, the formula Iq ′=I*cosθ and I d ′=I*sinθ, the target total current can be calculated quickly and accurately.

[0023] 7. By obtaining the inductance difference between the q-axis and the d-axis of the permanent magnet motor; and through the inductance difference, performing data processing on the real-time flux and the target torque of the permanent magnet motor to obtain the stator winding current required for the target torque; in this way, by combining the real-time flux, the target matrix of the permanent magnet motor and the inductance difference, the stator winding current required for the target torque can be obtained more accurately.

[0024] 8. By inputting the inductance difference, the real-time flux linkage, the target torque of the permanent magnet motor and the current angle into the formula The stator winding current required for the target torque can be obtained; wherein, T represents the target torque, PN represents the number of pole pairs of the permanent magnet motor, (L d -L q ) represents the inductance difference, the I d ′,I q ' represents the stator winding current required for the target torque, In this way, by introducing the torque calculation formula By combining the inductance difference, the real-time flux linkage, the target torque of the permanent magnet motor, and the current angle, the stator winding current required for the target torque can be calculated more conveniently.

[0025] 9. By obtaining the real-time temperature and initial temperature of the stator winding of the permanent magnet motor, combining the real-time temperature and the resistance of the stator winding at the initial temperature to adjust the real-time resistance of the stator winding at the real-time temperature, the real-time resistance of the stator winding at the real-time temperature can be calculated; wherein, the real-time resistance satisfies the formula R=R0(t+k) / (t0+k), R represents the real-time resistance, t represents the real-time temperature, t0 represents the initial temperature, and k represents the reciprocal of the resistance temperature coefficient of the conductor material at 0°C; the real-time resistance, the real-time stator winding current, the inductance of the permanent magnet motor, and the speed of the permanent magnet motor are input into the formula The real-time flux linkage of the permanent magnet motor is obtained; wherein, represents the real-time magnetic flux, U q represents the real-time stator winding voltage, L d represents the inductance of the permanent magnet motor, w e represents the speed of the permanent magnet motor, I d represents the real-time stator winding current. Thus, by introducing the formula Combined with real-time parameters such as real-time stator winding current and real-time stator winding voltage, the real-time magnetic flux of the permanent magnet motor can be accurately evaluated, which facilitates the subsequent more accurate acquisition of the target torque command. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of an implementation flow of a torque control method for a permanent magnet motor provided by an embodiment of the present invention;

[0028] Figure 2 It is another implementation flow diagram of a method for controlling the torque of a permanent magnet motor provided by an embodiment of the present invention;

[0029] Figure 3 It is another implementation flow diagram of a method for controlling the torque of a permanent magnet motor provided by an embodiment of the present invention;

[0030] Figure 4 It is another implementation flow diagram of a method for controlling the torque of a permanent magnet motor provided by an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of the composition structure of a torque control device for a permanent magnet motor provided by an embodiment of the present invention;

[0032] Figure 6 It is a structural schematic diagram of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the torque control method of a permanent magnet motor proposed by the present invention, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0034] Among them, in the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a way to describe the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" refers to two or more than two.

[0035] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0037] The following is a detailed description of a method for controlling the torque of a permanent magnet motor provided by the present invention in conjunction with the accompanying drawings. Figure 1 , which shows a schematic diagram of an implementation flow of a torque control method for a permanent magnet motor provided by an embodiment of the present invention, the method comprising:

[0038] 101, obtaining a real-time stator winding voltage and a real-time stator winding current in a permanent magnet motor.

[0039] Here, the real-time stator winding voltage U is obtained through the permanent magnet motor controller. q and real-time stator winding current; wherein the real-time stator winding current includes: the d-axis and q-axis currents of the stator winding.

[0040] In some possible implementations, the q-axis real-time stator winding voltage, q-axis real-time stator winding voltage, and d-axis real-time stator winding current of the stator winding in the permanent magnet motor are obtained; and the q-axis real-time stator winding voltage and the q-axis real-time stator winding voltage are determined as the real-time stator winding voltage, and the d-axis real-time stator winding current is determined as the real-time stator winding current. In this way, the real-time voltage of the stator winding of the permanent magnet motor and the real-time currents of the q-axis and the d-axis are obtained in real time through the controller, so as to facilitate the real-time calculation of the magnetic flux of the motor.

[0041] 102. Determine a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current.

[0042] Here, the real-time flux linkage of the permanent magnet motor is calculated by combining the temperature of the stator winding of the permanent magnet motor, the real-time stator winding voltage, and the real-time stator winding current.

[0043] In some possible implementations, the above step 102 can be performed by Figure 2 The steps shown achieve:

[0044] 201. Obtain the real-time temperature and initial temperature of the stator winding of the permanent magnet motor.

[0045] Here, the temperature of the stator winding is collected in real time, so as to obtain the real-time temperature of the stator winding.

[0046] 202. Based on the real-time temperature and the initial temperature, adjust the resistance of the stator winding at the initial temperature to obtain the real-time resistance of the stator winding at the real-time temperature.

[0047] Here, the real-time temperature t, the initial temperature t0, the resistance R0 of the motor stator winding at the initial temperature t0, and the inverse k of the resistance temperature coefficient of the conductor material at 0°C (where k=235 for copper and k=225 for aluminum) are combined to calculate the real-time resistance R of the stator winding at the real-time temperature, as shown in formula (1):

[0048] R = R0(t+k) / (t0+k) (1);

[0049] 203 , obtaining a real-time flux linkage of the permanent magnet motor based on the real-time resistance value, the real-time stator winding current, the inductance of the permanent magnet motor, and the rotation speed of the permanent magnet motor.

[0050] Here, the real-time resistance value, the real-time stator winding current, the inductance of the permanent magnet motor, and the speed of the permanent magnet motor are input into the formula: The real-time flux linkage of the permanent magnet motor is obtained.

[0051] here, represents the real-time magnetic flux, U q represents the real-time stator winding voltage, L d represents the inductance of the permanent magnet motor, w e represents the speed of the permanent magnet motor, I d Represents the real-time stator winding current.

[0052] The real-time resistance R and the real-time stator winding current I of the stator winding on the q axis are q Multiply them together to get the multiplication result, and calculate the inductance L of the permanent magnet motor on the d axis. d , the speed of permanent magnet motor w e and the real-time stator winding current I of the stator winding on the d-axis d Multiply them together to get another multiplication result. The real-time stator winding voltage U of the stator winding on the q axis q Subtract the two multiplication results and divide by the permanent magnet motor speed w e, you can get the real-time flux linkage of the permanent magnet motor As shown in formulas (2) and (3):

[0053]

[0054]

[0055] Among them, I d , I q They represent the real-time stator winding current of the d-axis and the real-time stator winding current of the q-axis of the stator winding respectively; L d represents the inductance of the permanent magnet motor on the d-axis; w e is the speed of the permanent magnet motor; U q represents the q-axis voltage of the stator winding; R represents the resistance of the stator winding at the real-time temperature t.

[0056] In the above steps 201 to 205, by comprehensively considering the temperature of the stator winding of the permanent magnet motor, the real-time stator winding voltage and the real-time stator winding current, the magnetic flux of the permanent magnet motor can be calculated accurately and in real time, thereby improving the real-time and accuracy of calculating the magnetic flux of the permanent magnet motor.

[0057] 103. Determine a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor.

[0058] Here, the target total current required for the target torque can be calculated through the real-time flux linkage and the target torque of the permanent magnet motor.

[0059] 104. Determine a target torque instruction for controlling the output of the permanent magnet motor based on the target total current and a preset correspondence table.

[0060] The preset correspondence table is used to characterize the correspondence between current and torque command. After the target total current required for the target torque is calculated, the corresponding torque command is searched in the preset correspondence table according to the target total current to obtain the target torque command capable of controlling the permanent magnet motor to output the target torque.

[0061] In some possible implementations, the target torque command is obtained by searching the preset correspondence table for the torque command that matches the target total current; and limiting the torque command that matches the target total current. Since the preset correspondence table stores the correspondence between the target total current and the torque command, after the target total current is calculated, the table can be looked up to obtain the torque command that matches the target total current; in this way, the torque command that matches the target total current is obtained through the preset correspondence table, and the torque command is limited, so that the target torque command obtained can be more accurate.

[0062] In some possible implementations, the target torque command is obtained by obtaining a preset limit range and adjusting the torque command that matches the target total current based on the preset limit range. The preset limit range can be customized, for example, the preset limit range is min(T ref1 *0.97,T ref1 -3)~max(T ref1 *1.03,T ref1 +3); where T ref1 In this way, by adjusting the limit of the torque command matching the target total current, the target torque command can accurately control the output target torque of the permanent magnet motor.

[0063] In an embodiment of the present invention, by obtaining the real-time stator winding voltage and the real-time stator winding current in the permanent magnet motor, the real-time flux of the motor can be calculated in real time according to the real-time stator winding voltage and the real-time stator winding current; in this way, the flux of the permanent magnet motor is estimated online, so that the real-time performance is better. Afterwards, based on the real-time flux and the target torque of the permanent magnet motor, the target total current required for the target torque is determined; and based on the target total current and the preset correspondence table, the target torque instruction of the permanent magnet motor is determined; wherein the preset correspondence table is used to characterize the correspondence between the current and the torque instruction. In this way, through the real-time flux and the target torque of the permanent magnet motor, the target total current that meets the target torque can be accurately calculated, so that by searching the preset relationship table, the target torque instruction of the permanent magnet motor can be obtained, so that the permanent magnet motor can output the required target torque under the target torque instruction, thereby overcoming the influence of temperature on the output torque, and the accuracy is high.

[0064] In some possible implementations, the above step 103 can be performed by Figure 3 The steps shown achieve:

[0065] 301, obtaining a total current corresponding to a given torque command, and a given current of the stator winding of the permanent magnet motor on the q-axis and the d-axis.

[0066] Here, the calculation formula of electromagnetic torque T is shown in formula (4):

[0067]

[0068] The motors used in vehicles are all calibrated and given a torque command T ref0 In fact, the current table is looked up to obtain the corresponding total current I and the given current I of the d-axis and q-axis. d0 ,I q0 .

[0069] 302 : Determine a current angle between the q-axis and the d-axis based on the total current and the given currents of the q-axis and the d-axis.

[0070] Here, the total current I, the given current I of the q-axis and the d-axis d0 ,I q0 Substituting into equations (5) and (6), we can obtain the current angle θ between the q-axis and the d-axis.

[0071] I q0 =I*cosθ (5);

[0072] I d0 =I*sinθ (6);

[0073] 303 : Determine a target total current required for the target torque based on the current angle, the real-time flux linkage, and the target torque of the permanent magnet motor.

[0074] In some possible implementations, the stator winding current required for the target torque is determined by using the real-time flux linkage and the target torque of the permanent magnet motor; here, by obtaining the inductance difference between the q-axis and the d-axis of the permanent magnet motor (L d -L q ); and based on the inductance difference, performing data processing on the real-time flux and the target torque of the permanent magnet motor to obtain the stator winding current required for the target torque.

[0075] In some possible implementations, the real-time flux, the inductance difference, and the number of pole pairs of the permanent magnet motor are combined to obtain a combined flux; for example, the real-time flux, the inductance difference, and the number of pole pairs of the permanent magnet motor are multiplied to obtain the combined flux. Then, the combined flux is adjusted based on the target torque to obtain the stator winding current required for the target torque; here, the inductance difference, the real-time flux, the target torque of the permanent magnet motor, and the corresponding current angle are input into the formula The stator winding current required for the target torque is obtained; wherein T represents the target torque, PN represents the number of pole pairs of the permanent magnet motor, (L d -L q ) represents the inductance difference, the I d ′,I q ' represents the stator winding current required for the target torque, In this way, by substituting the real-time flux, inductance difference, pole pair number and target torque into the electronic torque formula, the stator winding current required for the target torque can be quickly and accurately calculated. For example, by substituting the real-time flux, inductance difference, pole pair number and target torque of the permanent magnet motor into the above formula (1), the stator winding current I required for the target torque can be calculated. d ′,I q '. Then, based on the stator winding current required for the target torque and the current angle, the target total current is determined. Wherein, the stator winding current required for the target torque and the target total current satisfy the formula: I q ′=I*cosθ and I d ′=I*sinθ, that is (I q ′) 2 +(I d ′) 2 =I; where, I d ′,I q 'respectively represent the stator winding current required for the target torque, I represents the target total current, and θ represents the current angle. For example, the stator winding current and the current angle required for the target torque can be substituted into formula (5) or (6) to obtain the target total current.

[0076] Here, as the temperature of the permanent magnet motor rises, the flux decreases, and the torque command T is given. ref0 The actual output torque T' is less than the target torque T corresponding to the given command ref0 ′, as shown in formula (7):

[0077]

[0078] Based on this, the torque needs to be compensated and a new torque command is given to output the target torque T ref0 ′.

[0079] For a calibrated permanent magnet motor, at the same speed, when the current changes slightly, the current angle θ changes very little and can be approximated to be constant. Substituting the target torque into formula (4) and combining formulas (5) and (6), the stator winding current I of the q-axis and d-axis can be obtained: d ′,I q ′, and through the stator winding current I d ′,I q ′, the target total current required for the target torque is calculated. In this way, by combining the current angle, real-time flux linkage and the target torque of the permanent magnet motor, the target total current required for the target torque can be accurately calculated.

[0080] The torque control method of the permanent magnet motor provided by the embodiment of the present invention can be achieved by Figure 4The steps described achieve:

[0081] 401 , estimating winding resistance R based on the real-time temperature t, initial temperature t0 and corresponding initial temperature value R0 of the stator winding.

[0082] 402, based on winding resistance R, speed w e , voltage U q 、Inductance L d 、Inductance L q 、Current I d and current I q , estimate the real-time magnetic link.

[0083] Here, the current I d 、Current I q is the current under a given torque command.

[0084] 403, based on current I d and current I q , determine the current angle between the d-axis and the q-axis corresponding to the given torque command.

[0085] 404 , the target torque, current angle and other parameters are substituted into the calculation formula of the electromagnetic torque to obtain the stator winding currents of the d-axis and the q-axis.

[0086] 405, based on the stator winding current, calculate the target total current, and then look up the table to obtain a new torque command.

[0087] 406 , performing torque limit on the new torque command to obtain a target torque command.

[0088] 407, output the target torque command.

[0089] In an embodiment of the present invention, the target torque instruction is obtained by estimating the real-time flux and solving the electromagnetic torque equation for the current values ​​of the d-axis and q-axis required under the current flux, thereby adjusting the output torque, overcoming the influence of temperature on the output torque, and improving the real-time and accuracy of the output torque.

[0090] The present invention provides a torque control device for a permanent magnet motor. Figure 5 , which shows a schematic diagram of the composition structure of a torque control device for a permanent magnet motor provided by an embodiment of the present invention, the device 500 includes:

[0091] An acquisition module 501 is used to acquire the real-time stator winding voltage and the real-time stator winding current in the permanent magnet motor;

[0092] A first determination module 502, configured to determine a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current;

[0093] A second determination module 503 is used to determine a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor;

[0094] The third determination module 504 is used to determine the target torque instruction for controlling the output of the permanent magnet motor based on the target total current and a preset correspondence table; wherein the preset correspondence table is used to characterize the correspondence between current and torque instructions.

[0095] In some possible implementations, the third determination module 504 is further configured to search the preset correspondence table for a torque instruction that matches the target total current; and perform a limiting process on the torque instruction that matches the target total current to obtain the target torque instruction.

[0096] In some possible implementations, the third determination module 504 is further configured to obtain a preset limit range; and adjust the torque command that matches the target total current based on the preset limit range to obtain the target torque command.

[0097] In some possible implementations, the acquisition module 501 is also used to obtain the q-axis real-time stator winding voltage, the q-axis real-time stator winding voltage and the d-axis real-time stator winding current of the stator winding in the permanent magnet motor; determine the q-axis real-time stator winding voltage and the q-axis real-time stator winding voltage as the real-time stator winding voltage, and determine the d-axis real-time stator winding current as the real-time stator winding current.

[0098] In some possible implementations, the second determination module 503 is also used to obtain the total current corresponding to the given torque command, and the given current of the stator winding of the permanent magnet motor on the q-axis and the d-axis; based on the total current and the given currents of the q-axis and the d-axis, determine the current angle between the q-axis and the d-axis; based on the current angle, the real-time magnetic flux and the target torque of the permanent magnet motor, determine the target total current required for the target torque.

[0099] In some possible implementations, the second determination module 503 is further used to determine the stator winding current required for the target torque based on the real-time flux and the target torque of the permanent magnet motor; determine the target total current based on the stator winding current required for the target torque and the current angle; wherein the stator winding current required for the target torque and the target total current satisfy the formula: I q ′=I*cosθ and I d ′=I*sinθ; where, I d ′,I q′ respectively represent the stator winding current required for the target torque, I represents the target total current, and θ represents the current angle.

[0100] In some possible implementations, the second determination module 503 is also used to obtain the inductance difference between the q-axis and the d-axis of the permanent magnet motor; based on the inductance difference, the real-time magnetic flux and the target torque of the permanent magnet motor are processed to obtain the stator winding current required for the target torque.

[0101] In some possible implementations, the second determination module 503 is further configured to input the inductance difference, the real-time flux linkage, the target torque of the permanent magnet motor and the corresponding current angle into a formula: The stator winding current required for the target torque is obtained; wherein T represents the target torque, PN represents the number of pole pairs of the permanent magnet motor, (L d -L q ) represents the inductance difference, the I d ′,I q ' represents the stator winding current required for the target torque, Indicates the real-time magnetic link.

[0102] In some possible implementations, the first determination module 502 is further used to obtain the real-time temperature and initial temperature of the stator winding of the permanent magnet motor; based on the real-time temperature and the initial temperature, the resistance of the stator winding at the initial temperature is adjusted to obtain the real-time resistance of the stator winding at the real-time temperature; wherein the real-time resistance satisfies the formula R=R0(t+k) / (t0+k), R represents the real-time resistance, t represents the real-time temperature, t0 represents the initial temperature, and k represents the inverse of the resistance temperature coefficient of the conductor material at 0°C; the real-time resistance, the real-time stator winding current, the inductance of the permanent magnet motor, and the speed of the permanent magnet motor are input into the formula The real-time flux linkage of the permanent magnet motor is obtained; wherein, represents the real-time magnetic flux, U q represents the real-time stator winding voltage, L d represents the inductance of the permanent magnet motor, w e represents the speed of the permanent magnet motor, I d Represents the real-time stator winding current.

[0103] Optionally, the transmission medium can be a wired link (for example, but not limited to, coaxial cable, optical fiber and digital subscriber line (DSL), etc.) or a wireless link (for example, but not limited to, wireless Fidelity (WIFI), Bluetooth and mobile device network, etc.). It should be noted that: the device provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above. In addition, the method embodiments provided in the above embodiments belong to the same concept. The specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0104] Figure 6 is a schematic diagram of the structure of a computer device provided by an embodiment of the present invention. Figure 6 As shown, the computer device 600 includes: a memory 601, a processor 602, and a computer program 603 stored in the memory 601 and running on the processor 602, wherein when the processor 602 executes the computer program 603, the computer device can execute any one of the permanent magnet motor torque control methods described above.

[0105] In addition, an embodiment of the present invention also protects a system, which may include a memory and a processor, wherein an executable program code is stored in the memory, and the processor is used to call and execute the executable program code to perform a torque control method for a permanent magnet motor provided by an embodiment of the present invention. This embodiment can divide the system into functional modules according to the above method example. For example, it can correspond to each functional module, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic, which is only a logical function division, and there may be other division methods in actual implementation. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0106] It should be understood that the device provided in this embodiment is used to execute the above-mentioned torque control method of a permanent magnet motor, so the same effect as the above-mentioned implementation method can be achieved. In the case of an integrated unit, the device may include a processing module and a storage module. Among them, when the device is applied to a device, the processing module can be used to control and manage the actions of the device. The storage module can be used to support the device to execute mutual program codes, etc. Among them, the processing module can be a processor or a controller, which can implement or execute various exemplary logic boxes, modules and circuits described in combination with the disclosure of the present invention. The processor can also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc., and the storage module can be a memory.

[0107] In addition, the device provided in the embodiment of the present invention may be a chip, a component or a module, and the chip may include a connected processor and a memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a permanent magnet motor torque control method provided in the above embodiment. This embodiment also provides a computer-readable storage medium, in which a computer program code is stored, and when the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a permanent magnet motor torque control method provided in the above embodiment.

[0108] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer executes the above-mentioned related steps to implement a torque control method for a permanent magnet motor provided in the above embodiment. Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here. Through the description of the above implementation mode, the technicians in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In practical applications, the above-mentioned function allocation can be completed by different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In the embodiments provided by the present invention, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiment described above is only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, which may be electrical, mechanical or other forms.

[0109] It should be noted that the sequence of the above-mentioned embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or may be advantageous. The various embodiments in this specification are described in a progressive manner, and the same and similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments. The above content is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the torque of a permanent magnet motor, characterized in that: The torque control method of the permanent magnet motor comprises: Obtaining real-time stator winding voltage and real-time stator winding current in a permanent magnet motor; Determining a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current; Determining a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor; Based on the target total current and a preset correspondence table, a target torque instruction for controlling the output of the permanent magnet motor is determined; wherein the preset correspondence table is used to characterize the correspondence between the current and the torque instruction.

2. The method for controlling the torque of a permanent magnet motor according to claim 1, characterized in that: The determining, based on the target total current and a preset correspondence table, a target torque instruction for controlling the output of the permanent magnet motor comprises: Searching the preset correspondence table for a torque command that matches the target total current; The torque command matching the target total current is limited to obtain the target torque command.

3. The method for controlling the torque of a permanent magnet motor according to claim 2, characterized in that: The step of performing a limiting process on the torque command matching the target total current to obtain the target torque command includes: Get the preset limit range; The torque command matching the target total current is adjusted based on the preset limit range to obtain the target torque command.

4. The method for controlling the torque of a permanent magnet motor according to claim 1, characterized in that: The step of obtaining the real-time stator winding voltage and the real-time stator winding current in the permanent magnet motor includes: Obtaining a q-axis real-time stator winding voltage, a q-axis real-time stator winding voltage, and a d-axis real-time stator winding current of a stator winding in the permanent magnet motor; The q-axis real-time stator winding voltage and the d-axis real-time stator winding voltage are determined as the real-time stator winding voltage, and the d-axis real-time stator winding current is determined as the real-time stator winding current.

5. The method for controlling the torque of a permanent magnet motor according to claim 1, characterized in that: Before determining the target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor, the method further includes: Obtaining a total current corresponding to a given torque command, and a given current of the stator winding of the permanent magnet motor on the q-axis and the d-axis; determining a current angle between the q-axis and the d-axis based on the total current and the given currents of the q-axis and the d-axis; Correspondingly, determining the target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor includes: A target total current required for the target torque is determined based on the current angle, the real-time flux linkage, and the target torque of the permanent magnet motor.

6. The method for controlling the torque of a permanent magnet motor according to claim 5, characterized in that: The determining the target total current required for the target torque based on the current angle, the real-time flux linkage and the target torque of the permanent magnet motor comprises: Determining a stator winding current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor; Based on the stator winding current required for the target torque and the current angle, the target total current is determined; wherein the stator winding current required for the target torque and the target total current satisfy the formula: I q ′=I*cosθ and I d ′=I*sinθ; where, I d ′,I q ′ respectively represent the stator winding current required for the target torque, I represents the target total current, and θ represents the current angle.

7. The method for controlling the torque of a permanent magnet motor according to claim 6, characterized in that: Before determining the stator winding current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor, the method further includes: Obtaining an inductance difference between a q-axis and a d-axis of the permanent magnet motor; Correspondingly, determining the stator winding current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor includes: Based on the inductance difference, data processing is performed on the real-time flux linkage and the target torque of the permanent magnet motor to obtain the stator winding current required for the target torque.

8. The method for controlling the torque of a permanent magnet motor according to claim 7, characterized in that: The performing data processing on the real-time flux linkage and the target torque of the permanent magnet motor based on the inductance difference to obtain the stator winding current required for the target torque includes: The inductance difference, the real-time flux, the target torque of the permanent magnet motor and the corresponding current angle are input into the formula The stator winding current required for the target torque is obtained; wherein T represents the target torque, PN represents the number of pole pairs of the permanent magnet motor, (L d -L q ) represents the inductance difference, the I d ′,I q ' represents the stator winding current required for the target torque, Indicates the real-time magnetic link.

9. The method for controlling the torque of a permanent magnet motor according to claim 1, characterized in that: Before determining the real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current, the method further includes: Acquiring the real-time temperature and initial temperature of the stator winding of the permanent magnet motor; Correspondingly, determining the real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current includes: Based on the real-time temperature and the initial temperature, the resistance of the stator winding at the initial temperature is adjusted to obtain the real-time resistance of the stator winding at the real-time temperature; wherein the real-time resistance satisfies the formula R=R0(t+k) / (t0+k), R represents the real-time resistance, t represents the real-time temperature, t0 represents the initial temperature, and k represents the inverse of the resistance temperature coefficient of the conductor material at 0°C; Input the real-time resistance value, the real-time stator winding current, the inductance of the permanent magnet motor, and the speed of the permanent magnet motor into the formula The real-time flux linkage of the permanent magnet motor is obtained; wherein, represents the real-time magnetic flux, U q represents the real-time stator winding voltage, L d represents the inductance of the permanent magnet motor, w e represents the speed of the permanent magnet motor, I d Represents the real-time stator winding current.

10. A torque control device for a permanent magnet motor, characterized in that: The device comprises: An acquisition module, used for acquiring real-time stator winding voltage and real-time stator winding current in the permanent magnet motor; A first determination module, configured to determine a real-time flux linkage of the permanent magnet motor based on the real-time stator winding voltage and the real-time stator winding current; A second determination module is used to determine a target total current required for the target torque based on the real-time flux linkage and the target torque of the permanent magnet motor; The third determination module is used to determine the target torque instruction for controlling the output of the permanent magnet motor based on the target total current and a preset correspondence table; wherein the preset correspondence table is used to characterize the correspondence between current and torque instructions.

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