阅读说明：本技术 电机最大转矩电流比控制方法、装置和计算机可读介质 (Motor maximum torque current ratio control method, device and computer readable medium ) 是由 薛海芬 于 2020-05-28 设计创作，主要内容包括：本发明提供了电机最大转矩电流比控制方法、装置和计算机可读介质,该电机最大转矩电流比控制方法包括：获取第一电磁转矩,其中,所述第一电磁转矩用于表征永磁同步电机所需产生的电磁转矩；根据所述第一电磁转矩和预设的第一映射关系,确定目标交轴电流和目标直轴电流,其中,所述第一映射关系用于表征所述永磁同步电机中交轴电流和直轴电流与电磁转矩之间的几何关系；根据所述目标交轴电流和所述目标直轴电流控制所述永磁同步电机运行。本方案能够提高永磁同步电机的效率。(The invention provides a method, a device and a computer readable medium for controlling the maximum torque current ratio of a motor, wherein the method for controlling the maximum torque current ratio of the motor comprises the following steps: acquiring a first electromagnetic torque, wherein the first electromagnetic torque is used for representing the electromagnetic torque required to be generated by the permanent magnet synchronous motor; determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and a preset first mapping relation, wherein the first mapping relation is used for representing a geometric relation between the quadrature-axis current and the electromagnetic torque of the permanent magnet synchronous motor and between the direct-axis current and the electromagnetic torque; and controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current. The scheme can improve the efficiency of the permanent magnet synchronous motor.)

1. The method for controlling the maximum torque current ratio of the motor is characterized by comprising the following steps:

acquiring a first electromagnetic torque, wherein the first electromagnetic torque is used for representing the electromagnetic torque (101) required to be generated by a permanent magnet synchronous motor (702);

determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and a preset first mapping relation, wherein the first mapping relation is used for representing a geometric relation (102) between the quadrature-axis current and the direct-axis current and the electromagnetic torque in the permanent magnet synchronous motor (702);

and controlling the permanent magnet synchronous motor (702) to operate (103) according to the target quadrature axis current and the target direct axis current.

2. The method of claim 1, wherein determining a target quadrature-axis current and a target direct-axis current from the first electromagnetic torque and a first mapping comprises:

calculating the target quadrature-axis current and the target direct-axis current according to the first electromagnetic torque and a flux linkage of a permanent magnet in the permanent magnet synchronous motor (702) through the following equation set;

wherein, the i_qFor characterizing the target quadrature axis current, said i_dFor characterizing the target direct axis current, the psi_fFor characterizing the flux linkage, and the Δ L for characterizing the permanent magnetDifference between quadrature axis inductance and direct axis inductance of the stepper motor (702), T_{e_ref}For characterizing said first electromagnetic torque, said n_pFor characterizing the pole pair number of the permanent magnet synchronous machine (702).

3. The method of claim 1, wherein determining a target quadrature-axis current and a target direct-axis current from the first electromagnetic torque and a first mapping comprises:

acquiring a second electromagnetic torque, wherein the second electromagnetic torque is used for representing the electromagnetic torque (402) referred to in the control process of the permanent magnet synchronous motor (702);

performing PI regulation by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current (403);

determining a first direct-axis current according to the first quadrature-axis current and a preset second geometric mapping relation, wherein the second geometric mapping relation is used for representing the geometric relation (404) between the quadrature-axis current and the direct-axis current under the condition of the maximum torque-current ratio;

calculating a third electromagnetic torque (405) from the first quadrature axis current and the first direct axis current;

determining whether the third electromagnetic torque is equal to the first electromagnetic torque (406);

determining the first quadrature axis current as the target quadrature axis current and the first direct axis current as the target direct axis current if the third electromagnetic torque is equal to the first electromagnetic torque (407);

and if the third electromagnetic torque is not equal to the first electromagnetic torque, taking the third electromagnetic torque as the second electromagnetic torque, and executing PI regulation by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current (408).

4. The method of claim 3, wherein determining a first direct current from the first quadrature-axis current and a predetermined geometric mapping comprises:

calculating the first direct-axis current according to a first formula as follows according to a flux linkage of a permanent magnet in the permanent magnet synchronous motor (702), quadrature-axis inductance and direct-axis inductance of the permanent magnet synchronous motor (702) and the first quadrature-axis current;

the first formula includes:

wherein, the i_qFor characterizing the first quadrature axis current, i_dFor characterizing said first direct current, said psi_fThe delta L is used for representing the difference between the quadrature axis inductance and the direct axis inductance.

5. The method of claim 4, wherein calculating a third electromagnetic torque based on the first quadrature axis current and the first direct axis current comprises:

calculating the third electromagnetic torque according to the pole pair number, the flux linkage, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current and the first direct axis current of the permanent magnet synchronous motor (702) by a second formula;

the second formula includes:

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T is_{e_calc}For characterizing said third electromagnetic torque, said n_pFor characterizing the number of pole pairs of the permanent magnet synchronous machine (702), L_qFor characterizing the quadrature inductance, L_dFor characterizing the direct axis inductance.

6. The method according to any of claims 1 to 5, wherein said controlling the permanent magnet synchronous machine (702) according to the target quadrature axis current and the target direct axis current comprises:

acquiring a second quadrature-axis current and a second direct-axis current, wherein the second quadrature-axis current is used for representing an actual quadrature-axis current of the permanent magnet synchronous motor (702), and the second direct-axis current is used for representing an actual direct-axis current (601) of the permanent magnet synchronous motor (702);

performing PI regulation by taking the difference between the target quadrature axis current and the second quadrature axis current as input to obtain a quadrature axis control signal (602);

taking the difference between the target direct-axis current and the second direct-axis current as input to perform PI regulation to obtain a direct-axis control signal (603);

and transmitting the quadrature axis control signal and the direct axis control signal to an inverter (701) connected with the permanent magnet synchronous motor (702), so that the inverter (701) transmits three-phase power to the permanent magnet synchronous motor (702) according to the quadrature axis control signal and the direct axis control signal, the quadrature axis current of the permanent magnet synchronous motor (702) is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor (702) is equal to the target direct axis current (604).

7. The maximum torque current ratio control device of the motor is characterized by comprising:

a torque acquisition module (81) for acquiring a first electromagnetic torque, wherein the first electromagnetic torque is used for representing the electromagnetic torque required to be generated by the permanent magnet synchronous motor (702);

a current obtaining module (82) configured to determine a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque obtained by the torque obtaining module (81) and a preset first mapping relationship, where the first mapping relationship is used to represent a geometric relationship between the quadrature-axis current and the direct-axis current in the permanent magnet synchronous motor (702) and the electromagnetic torque;

and the motor control module (83) is used for controlling the permanent magnet synchronous motor (702) to operate according to the target quadrature axis current and the target direct axis current acquired by the current acquisition module (82).

8. The apparatus of claim 7,

the current acquisition module (82) is used for calculating the target quadrature axis current and the target direct axis current according to the first electromagnetic torque and the flux linkage of permanent magnets in the permanent magnet synchronous motor (702) through the following equation set;

wherein, the i_qFor characterizing the target quadrature axis current, said i_dFor characterizing the target direct axis current, the psi_fFor characterizing the flux linkage, said Δ L for characterizing a difference between a quadrature axis inductance and a direct axis inductance of the permanent magnet synchronous machine (702), said T_{e_ref}For characterizing said first electromagnetic torque, said n_pFor characterizing the pole pair number of the permanent magnet synchronous machine (702).

9. The apparatus of claim 7, wherein the current acquisition module (82) comprises:

a first acquisition unit (821) for acquiring a second electromagnetic torque, wherein the second electromagnetic torque is used for representing the electromagnetic torque referred to in the control process of the permanent magnet synchronous motor (702);

a first PI adjusting unit (822) for performing PI adjustment by taking the difference between the first electromagnetic torque and the second electromagnetic torque acquired by the first acquiring unit (821) as input to acquire a first quadrature axis current;

a first calculating unit (823) configured to determine a first direct current according to the first quadrature axis current acquired by the first PI adjusting unit (822) and a preset second geometric mapping relationship, where the second geometric mapping relationship is used to represent a geometric relationship between the quadrature axis current and the direct axis current under a maximum torque-to-current ratio condition;

a second calculation unit (824) for calculating a third electromagnetic torque according to the first quadrature axis current acquired by the first PI adjustment unit (822) and the first direct axis current acquired by the first calculation unit (823);

a determination unit (825) for determining whether or not the third electromagnetic torque calculated by the second calculation unit (824) is equal to the first electromagnetic torque acquired by the torque acquisition module (81);

a current mapping unit (826) for determining the first quadrature-axis current as the target quadrature-axis current and the first direct-axis current as the target direct-axis current when the determination unit (825) determines that the third electromagnetic torque is equal to the first electromagnetic torque;

and the torque mapping unit (827) is used for taking the third electromagnetic torque as the second electromagnetic torque and triggering the first PI adjusting unit (822) to execute PI adjustment by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current when the judging unit (825) determines that the third electromagnetic torque is not equal to the first electromagnetic torque.

10. The apparatus of claim 9,

the first calculating unit (823) is configured to calculate the first direct current according to a first formula, according to a flux linkage of a permanent magnet in the permanent magnet synchronous motor (702), quadrature axis inductance and direct axis inductance of the permanent magnet synchronous motor (702), and the first quadrature axis current;

the first formula includes:

wherein, the i_qFor characterizing the first quadrature axis current, i_dFor characterizing said first direct current, said psi_fThe delta L is used for representing the difference between the quadrature axis inductance and the direct axis inductance.

11. The apparatus of claim 10,

the second calculation unit (824) is configured to calculate the third electromagnetic torque according to the pole pair number, the flux linkage, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current, and the first direct axis current of the permanent magnet synchronous motor (702) by using a second formula;

the second formula includes:

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T is_{e_calc}For characterizing said third electromagnetic torque, said n_pFor characterizing the number of pole pairs of the permanent magnet synchronous machine (702), L_qFor characterizing the quadrature inductance, L_dFor characterizing the direct axis inductance.

12. The device according to any one of claims 7 to 11, characterized in that said motor control module (83) comprises:

a second obtaining unit (831) for obtaining a second quadrature-axis current and a second direct-axis current, wherein the second quadrature-axis current is used for representing an actual quadrature-axis current of the permanent magnet synchronous motor (702), and the second direct-axis current is used for representing an actual direct-axis current of the permanent magnet synchronous motor (702);

a second PI regulating unit (832) for carrying out PI regulation by taking the difference between the target quadrature axis current and the second quadrature axis current obtained by the second obtaining unit (831) as input to obtain a quadrature axis control signal;

a third PI adjustment unit (833) for performing PI adjustment using the difference between the target direct-axis current and the second direct-axis current acquired by the second acquisition unit (831) as an input to obtain a direct-axis control signal;

and the signal transmission unit (834) is used for transmitting the quadrature axis control signal acquired by the second PI regulation unit (832) and the direct axis control signal acquired by the third PI regulation unit (833) to an inverter (701) connected with the permanent magnet synchronous motor (702), so that the inverter (701) transmits three-phase power to the permanent magnet synchronous motor (702) according to the quadrature axis control signal and the direct axis control signal, the quadrature axis current of the permanent magnet synchronous motor (702) is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor (702) is equal to the target direct axis current.

13. The maximum torque current ratio control device of the motor is characterized by comprising: at least one memory (84) and at least one processor (85);

the at least one memory (84) for storing a machine readable program;

the at least one processor (85) configured to invoke the machine readable program to perform the method of any of claims 1 to 6.

14. Computer readable medium, characterized in that it has stored thereon computer instructions which, when executed by a processor, cause the processor to carry out the method of any one of claims 1 to 6.

Technical Field

The invention relates to the technical field of electrical engineering, in particular to a method and a device for controlling the maximum torque-current ratio of a motor and a computer readable medium.

Background

A permanent-magnet synchronous motor (PMSM) has superior performances such as simple structure, small volume, light weight, and draft of power factor, and is widely applied to various industries of industrial production. The electromagnetic Torque of the permanent magnet synchronous motor is determined by flux linkage and Torque current, and the flux linkage is determined by a permanent magnet and weak magnetic/strong magnetic current components, so that the Torque currents may not be the same on the premise that the permanent magnet synchronous motor generates the same electromagnetic Torque, the permanent magnet synchronous motor is controlled by a Maximum Torque per Ampere Control (MTPA) method, and the minimum Torque current can be input when the permanent magnet synchronous motor outputs the same electromagnetic Torque.

At present, when a maximum torque current ratio control method is realized, because a nonlinear equation set representing the relationship between quadrature-axis current and direct-axis current and electromagnetic torque is complex, and the nonlinear equation set is difficult to solve in a controller by adopting an extreme value principle to obtain the required quadrature-axis current and direct-axis current, the relationship between the quadrature-axis current and the direct-axis current meeting the maximum torque current ratio control condition is generally linearized, and then the required quadrature-axis current and the required direct-axis current are solved through the linear relationship between the quadrature-axis current and the direct-axis current, so that the maximum torque current ratio control method is approximately realized.

Aiming at the current maximum torque current ratio control method of the permanent magnet synchronous motor, the relation between quadrature axis current and direct axis current under the condition of meeting the maximum torque current ratio control is linearized, and then the quadrature axis current and the direct axis current are solved through the linear relation between the quadrature axis current and the direct axis current.

Disclosure of Invention

In view of this, the method, the apparatus and the computer readable medium for controlling the maximum torque current ratio of the motor provided by the invention can improve the efficiency of the permanent magnet synchronous motor.

In a first aspect, an embodiment of the present invention provides a method for controlling a maximum torque current ratio of a motor, including:

acquiring a first electromagnetic torque, wherein the first electromagnetic torque is used for representing the electromagnetic torque required to be generated by the permanent magnet synchronous motor;

determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and a preset first mapping relation, wherein the first mapping relation is used for representing a geometric relation between the quadrature-axis current and the electromagnetic torque of the permanent magnet synchronous motor and between the direct-axis current and the electromagnetic torque;

and controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current.

In a first possible implementation manner, with reference to the first aspect, the determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and the first mapping relation includes:

calculating the target quadrature axis current and the target direct axis current according to the first electromagnetic torque and the flux linkage of a permanent magnet in the permanent magnet synchronous motor through the following equation set;

wherein, the i_qFor characterizing the target quadrature axis current, said i_dFor characterizing the target direct axis current, the psi_fIs used for representing the magnetic linkage, the delta L is used for representing the difference between quadrature axis inductance and direct axis inductance of the permanent magnet synchronous motor, and the T_{e_ref}For characterizing said first electromagnetic torque, said n_pThe method is used for representing the pole pair number of the permanent magnet synchronous motor.

In a second possible implementation manner, with reference to the first aspect, the determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and the first mapping relation includes:

acquiring a second electromagnetic torque, wherein the second electromagnetic torque is used for representing the electromagnetic torque referred to in the control process of the permanent magnet synchronous motor;

performing PI regulation by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current;

determining a first direct-axis current according to the first quadrature-axis current and a preset second geometric mapping relation, wherein the second geometric mapping relation is used for representing the geometric relation between the quadrature-axis current and the direct-axis current under the condition of the maximum torque-current ratio;

calculating a third electromagnetic torque according to the first quadrature axis current and the first direct axis current;

judging whether the third electromagnetic torque is equal to the first electromagnetic torque or not;

determining the first quadrature axis current as the target quadrature axis current and the first direct axis current as the target direct axis current if the third electromagnetic torque is equal to the first electromagnetic torque;

and if the third electromagnetic torque is not equal to the first electromagnetic torque, taking the third electromagnetic torque as the second electromagnetic torque, and executing PI regulation by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current.

In a third possible implementation manner, with reference to the second possible implementation manner, the determining a first direct current according to the first quadrature axis current and a preset geometric mapping relationship includes:

calculating the first direct-axis current according to a first formula as follows according to a flux linkage of a permanent magnet in the permanent magnet synchronous motor, quadrature axis inductance and direct axis inductance of the permanent magnet synchronous motor and the first quadrature axis current;

the first formula includes:

wherein, the i_qFor characterizing the first quadrature axis current, i_dFor characterizing said first direct current, said psi_fThe delta L is used for representing the difference between the quadrature axis inductance and the direct axis inductance.

In a fourth possible implementation manner, with reference to the third possible implementation manner, the calculating a third electromagnetic torque according to the first quadrature axis current and the first direct axis current includes:

calculating the third electromagnetic torque according to the pole pair number, the flux linkage, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current and the first direct axis current of the permanent magnet synchronous motor by using a second formula as follows;

the second formula includes:

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T is_{e_calc}For characterizing said third electromagnetic torque, said n_pFor characterizing the number of pole pairs of the permanent magnet synchronous machine, L_qFor characterizing the quadrature inductance, L_dFor characterizing the direct axis inductance.

In a fifth possible implementation manner, with reference to the first aspect and any one of the first possible implementation manner, the second possible implementation manner, the third possible implementation manner, and the fourth possible implementation manner of the first aspect, the controlling the permanent magnet synchronous motor according to the target quadrature-axis current and the target direct-axis current includes:

acquiring a second quadrature axis current and a second direct axis current, wherein the second quadrature axis current is used for representing an actual quadrature axis current of the permanent magnet synchronous motor, and the second direct axis current is used for representing an actual direct axis current of the permanent magnet synchronous motor;

performing PI regulation by taking the difference between the target quadrature axis current and the second quadrature axis current as input to obtain a quadrature axis control signal;

taking the difference between the target direct axis current and the second direct axis current as an input to perform PI regulation to obtain a direct axis control signal;

and transmitting the quadrature axis control signal and the direct axis control signal to an inverter connected with the permanent magnet synchronous motor, so that the inverter transmits three-phase power to the permanent magnet synchronous motor according to the quadrature axis control signal and the direct axis control signal, the quadrature axis current of the permanent magnet synchronous motor is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor is equal to the target direct axis current.

In a second aspect, an embodiment of the present invention further provides a maximum torque current ratio control apparatus for a motor, including:

the permanent magnet synchronous motor control device comprises a torque acquisition module, a control module and a control module, wherein the torque acquisition module is used for acquiring a first electromagnetic torque, and the first electromagnetic torque is used for representing the electromagnetic torque required to be generated by the permanent magnet synchronous motor;

the current acquisition module is used for determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque acquired by the torque acquisition module and a preset first mapping relation, wherein the first mapping relation is used for representing a geometric relation between the quadrature-axis current and the electromagnetic torque in the permanent magnet synchronous motor;

and the motor control module is used for controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current acquired by the current acquisition module.

In a first possible implementation manner, with reference to the second aspect, the current obtaining module is configured to calculate the target quadrature-axis current and the target direct-axis current according to the first electromagnetic torque and a flux linkage of a permanent magnet in the permanent magnet synchronous motor through the following equation set;

wherein, the i_qFor characterizing the target quadrature axis current, said i_dFor characterizing the target direct axis current, the psi_fIs used for representing the magnetic linkage, the delta L is used for representing the difference between quadrature axis inductance and direct axis inductance of the permanent magnet synchronous motor, and the T_{e_ref}For characterizing said first electromagnetic torque, said n_pThe method is used for representing the pole pair number of the permanent magnet synchronous motor.

In a second possible implementation manner, with reference to the first aspect, the current obtaining module includes:

the first acquisition unit is used for acquiring a second electromagnetic torque, wherein the second electromagnetic torque is used for representing the electromagnetic torque referred in the control process of the permanent magnet synchronous motor;

the first PI adjusting unit is used for carrying out PI adjustment by taking the difference between the first electromagnetic torque and the second electromagnetic torque acquired by the first acquiring unit as input to acquire a first quadrature axis current;

the first calculation unit is used for determining a first direct-axis current according to the first quadrature-axis current acquired by the first PI regulation unit and a preset second geometric mapping relation, wherein the second geometric mapping relation is used for representing the geometric relation between the quadrature-axis current and the direct-axis current under the condition of the maximum torque-current ratio;

the second calculation unit is used for calculating a third electromagnetic torque according to the first quadrature axis current acquired by the first PI regulation unit and the first direct axis current acquired by the first calculation unit;

a determination unit configured to determine whether the third electromagnetic torque calculated by the second calculation unit is equal to the first electromagnetic torque acquired by the torque acquisition module;

a current mapping unit configured to determine the first quadrature axis current as the target quadrature axis current and determine the first direct axis current as the target direct axis current when the determination unit determines that the third electromagnetic torque is equal to the first electromagnetic torque;

and the torque mapping unit is used for taking the third electromagnetic torque as the second electromagnetic torque and triggering the first PI adjusting unit to execute PI adjustment by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current when the judging unit determines that the third electromagnetic torque is not equal to the first electromagnetic torque.

In a third possible implementation manner, with reference to the second possible implementation manner, the first calculating unit is configured to calculate the first direct current according to a first formula as follows according to a flux linkage of a permanent magnet in the permanent magnet synchronous motor, a quadrature axis inductance and a direct axis inductance of the permanent magnet synchronous motor, and the first quadrature axis current;

the first formula includes:

wherein, the i_qFor characterizing the first quadrature axis current, i_dFor characterizing said first direct current, said psi_fThe delta L is used for representing the difference between the quadrature axis inductance and the direct axis inductance.

In a fourth possible implementation manner, with reference to the third possible implementation manner, the second calculating unit is configured to calculate the third electromagnetic torque according to a second formula as follows according to the number of pole pairs of the permanent magnet synchronous motor, the flux linkage, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current, and the first direct axis current;

the second formula includes:

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T is_{e_calc}For characterizing said third electromagnetic torque, said n_pFor characterizing the number of pole pairs of the permanent magnet synchronous machine, L_qFor characterizing the quadrature inductance, L_dFor characterizing the direct axis inductance.

In a fifth possible implementation manner, with reference to the second aspect and any one of the first possible implementation manner, the second possible implementation manner, the third possible implementation manner, and the fourth possible implementation manner of the second aspect, the motor control module includes:

a second obtaining unit, configured to obtain a second quadrature-axis current and a second direct-axis current, where the second quadrature-axis current is used to represent an actual quadrature-axis current of the permanent magnet synchronous motor, and the second direct-axis current is used to represent an actual direct-axis current of the permanent magnet synchronous motor;

the second PI adjusting unit is used for carrying out PI adjustment by taking the difference between the target quadrature axis current and the second quadrature axis current acquired by the second acquiring unit as input to acquire a quadrature axis control signal;

a third PI adjustment unit, configured to perform PI adjustment using a difference between the target direct axis current and the second direct axis current acquired by the second acquisition unit as an input, so as to obtain a direct axis control signal;

and the signal transmission unit is used for transmitting the quadrature axis control signal acquired by the second PI regulation unit and the direct axis control signal acquired by the third PI regulation unit to an inverter connected with the permanent magnet synchronous motor, so that the inverter transmits three-phase electricity to the permanent magnet synchronous motor according to the quadrature axis control signal and the direct axis control signal, the quadrature axis current of the permanent magnet synchronous motor is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor is equal to the target direct axis current.

In a third aspect, an embodiment of the present invention further provides another maximum torque current ratio control apparatus for a motor, including: at least one memory and at least one processor;

the at least one memory to store a machine readable program;

the at least one processor is configured to invoke the machine readable program to execute the method for controlling a maximum torque-to-current ratio of a motor provided in the first aspect and any possible implementation manner of the first aspect.

In a fourth aspect, the present invention further provides a computer-readable medium, where computer instructions are stored, and when executed by a processor, cause the processor to execute the method for controlling a maximum torque-to-current ratio of a motor provided in any one of the foregoing first aspect and possible implementations of the first aspect.

According to the technical scheme, a first mapping relation used for representing the geometric relation between the quadrature-axis current and the direct-axis current of the permanent magnet synchronous motor and the electromagnetic torque is preset, after the first electromagnetic torque required to be generated by the permanent magnet synchronous motor is obtained, the target quadrature-axis current and the target direct-axis current are determined according to the first electromagnetic torque and the first mapping relation, and then the permanent magnet synchronous motor is controlled to operate according to the determined target quadrature-axis current and the determined target direct-axis current. Because the first mapping relation represents the geometric relation between the quadrature-axis current, the direct-axis current and the electromagnetic torque, and the geometric relation between the quadrature-axis current, the direct-axis current and the electromagnetic torque is simpler, the target quadrature-axis current and the target direct-axis current can be quickly and conveniently determined in the controller according to the first mapping relation, the maximum torque-current ratio control of the permanent magnet synchronous motor is really realized according to the determined target quadrature-axis current and the target direct-axis current, the permanent magnet synchronous motor generates the first electromagnetic torque through the minimum torque current, and therefore the efficiency of the permanent magnet synchronous motor can be improved.

Drawings

FIG. 1 is a flow chart of a method for controlling a ratio of maximum torque to current of a motor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the geometric relationship between electromagnetic torque and torque current provided by one embodiment of the present invention;

FIG. 3 is a schematic illustration of another electromagnetic torque to torque current geometry provided by an embodiment of the present invention;

FIG. 4 is a flow chart of another method for controlling a ratio of maximum torque to current of a motor according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a motor torque capacity to current ratio control process provided by one embodiment of the present invention;

fig. 6 is a flowchart of a method for controlling an operation of a permanent magnet synchronous motor according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of another motor torque capacity to current ratio control process provided by an embodiment of the present invention;

fig. 8 is a schematic diagram of a maximum torque current ratio control apparatus for an electric motor according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of another motor torque capacity to current ratio control apparatus according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a maximum torque to current ratio control apparatus for a motor according to an embodiment of the present invention;

fig. 11 is a schematic diagram of a maximum torque current ratio control apparatus of a further motor according to an embodiment of the present invention.

List of reference numerals:

101: obtaining a first electromagnetic torque

102: determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and a preset first mapping relation

103: controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current

401: acquiring a first electromagnetic torque required to be generated by a permanent magnet synchronous motor

402: obtaining a second electromagnetic torque

403: the difference between the first electromagnetic torque and the second electromagnetic torque is used as an input to carry out PI regulation to obtain a first quadrature axis current

404: determining a first direct current according to the first quadrature current and a preset second geometric mapping relation

405: calculating a third electromagnetic torque according to the first quadrature axis current and the first direct axis current

406: judging whether the third electromagnetic torque is equal to the first electromagnetic torque or not

407: determine the first quadrature/direct current as the target quadrature/direct current, and execute step 409

408: using the third electromagnetic torque as the second electromagnetic torque, and executing step 403

409: controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current

601: obtaining a second quadrature axis current and a second direct axis current

602: the difference between the target quadrature axis current and the second quadrature axis current is used as an input to perform PI regulation to obtain a quadrature axis control signal

603: the difference between the target direct axis current and the second direct axis current is used as an input to perform PI regulation to obtain a direct axis control signal

604: the quadrature axis control signal and the direct axis control signal are transmitted to an inverter connected with the permanent magnet synchronous motor to control the motor to operate

81: the torque acquisition module 82: the current acquisition module 83: motor control module

821: the first acquisition unit 822: the first PI adjustment unit 823: first computing unit

824: the second calculation unit 825: the judging unit 826: current mapping unit

827: torque mapping unit 831: second acquisition unit 832: the PI regulation unit

833: third PI regulation unit 834: the signal transmission unit 84: memory device

85: the processor 701: inverter 702: permanent magnet synchronous motor

703: sampling sensor

Detailed Description

As described above, in order to implement the maximum torque current ratio control of the permanent magnet synchronous motor, it is necessary to solve a nonlinear equation set representing the relationship between the quadrature axis current and the direct axis current and the electromagnetic torque to obtain the target quadrature axis current and the target direct axis current for the maximum torque current ratio control of the permanent magnet synchronous motor, but since the nonlinear equation set is complicated, it is difficult to solve the nonlinear equation set in the controller by using a general extreme value principle, and therefore, the nonlinear equation set is converted into a linear relationship expression, and the linear relationship expression is solved to obtain an approximate target quadrature axis current and an approximate target direct axis current, so as to approximately implement the maximum torque current ratio control of the permanent magnet synchronous motor. The quadrature axis current and the direct axis current obtained by solving the linear relational expression are similar to the target quadrature axis current and the target direct axis current, so that the maximum torque current ratio control of the permanent magnet synchronous motor can only be approximately realized, but the maximum torque current ratio control is not really realized actually, so that the torque current is not minimum on the premise of determining the electromagnetic torque, and the efficiency of the permanent magnet synchronous motor is low.

In the embodiment of the invention, a first mapping relation used for representing the geometric relation between quadrature-axis current and direct-axis current in the permanent magnet synchronous motor and electromagnetic torque is predetermined, after first electromagnetic torque required to be generated by the permanent magnet synchronous motor is obtained, target quadrature-axis current and target direct-axis current which accord with maximum torque-current ratio control are determined according to the obtained first electromagnetic torque and the obtained first mapping relation, and then the permanent magnet synchronous motor is controlled to operate through the determined target quadrature-axis current and target direct-axis current. Because the first mapping relation represents the geometric relation between the quadrature-axis current and the electromagnetic torque and between the direct-axis current and the electromagnetic torque, and the geometric relation is more intuitive and brief, the target quadrature-axis current and the target direct-axis current can be quickly and conveniently determined according to the first electromagnetic torque and the first mapping relation, the maximum torque-current ratio control of the permanent magnet synchronous motor is really realized, the first electromagnetic torque is generated by the permanent magnet synchronous motor through the minimum torque current, and the efficiency of the permanent magnet synchronous motor can be improved.

The following describes a method and an apparatus for controlling a maximum torque current ratio of a motor according to an embodiment of the present invention in detail with reference to the accompanying drawings.

As shown in fig. 1, an embodiment of the present invention provides a method for controlling a maximum torque current ratio of a motor, which may include the following steps:

step 101: acquiring a first electromagnetic torque, wherein the first electromagnetic torque is used for representing the electromagnetic torque required to be generated by the permanent magnet synchronous motor;

step 102: determining a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and a preset first mapping relation, wherein the first mapping relation is used for representing a geometric relation between the quadrature-axis current and the electromagnetic torque of the permanent magnet synchronous motor and between the direct-axis current and the electromagnetic torque;

step 103: and controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current.

In the embodiment of the invention, a first mapping relation used for representing the geometric relation between quadrature-axis current and direct-axis current and electromagnetic torque in the permanent magnet synchronous motor is preset, after the first electromagnetic torque required to be generated by the permanent magnet synchronous motor is obtained, the target quadrature-axis current and the target direct-axis current are determined according to the first electromagnetic torque and the first mapping relation, and then the permanent magnet synchronous motor is controlled to operate according to the determined target quadrature-axis current and the determined target direct-axis current. Because the first mapping relation represents the geometric relation between the quadrature-axis current, the direct-axis current and the electromagnetic torque, and the geometric relation between the quadrature-axis current, the direct-axis current and the electromagnetic torque is simpler, the target quadrature-axis current and the target direct-axis current can be quickly and conveniently determined in the controller according to the first mapping relation, the maximum torque-current ratio control of the permanent magnet synchronous motor is really realized according to the determined target quadrature-axis current and the target direct-axis current, the permanent magnet synchronous motor generates the first electromagnetic torque through the minimum torque current, and therefore the efficiency of the permanent magnet synchronous motor can be improved.

In the embodiment of the present invention, in an ac-dc coordinate system, the torque equation of the permanent magnet synchronous motor may be expressed as the following formula (1), where the modulus I of the stator current vector of the permanent magnet synchronous motor is_sCan be expressed by the currents in the quadrature and direct directions as the following formula (2), where T_eFor characterizing electromagnetic torque, n_pPole pair number psi for characterizing a permanent magnet synchronous machine_qFor characterizing quadrature-axis flux linkage, psi_qFor characterizing the direct-axis flux linkage, #_qFor characterizing the flux linkage, L, of permanent magnets in a permanent magnet synchronous machine_qFor characterizing quadrature inductance, L_dFor characterizing the direct-axis inductance, i_qFor characterizing quadrature-axis current, i_dFor characterizing the direct axis current.

T_e＝n_p(ψ_di_q-ψ_qi_d)＝n_p[(ψ_f-L_di_d)i_q+L_qi_qi_d](1)

The torque equation of the permanent magnet synchronous motor can be further solved as the following formula (3), and then the quadrature axis current can be expressed as the following formula (4).

T_e＝n_p[ψ_fi_q+(L_q-L_d)i_di_q](3)

At i_dAnd i_qIn the coordinate system with the horizontal axis and the vertical axis, when the electromagnetic torque is constant more than 0, it can be seen from the above equation (4) that the curve of the constant electromagnetic torque is the upper half of the hyperbola in fig. 2 (the upper half of the solid line hyperbola and the upper half of the dotted line hyperbola respectively represent two curves of the constant electromagnetic torque having different magnitudes, and the electromagnetic torque corresponding to the upper half of the solid line hyperbola is larger than the electromagnetic torque corresponding to the upper half of the dotted line hyperbola). i.e. i_d-B is the asymptote of the curve of constant electromagnetic torque. As can be seen from the above equation (2), the stator current can be expressed as a circle having the origin as the center and the modulus of the current vector as the radius, as shown by two circles in fig. 2 (the circle with the solid line represents the stator current corresponding to the constant electromagnetic torque represented by the upper half of the hyperbolic line with the solid line, and the circle with the broken line represents the stator current corresponding to the constant electromagnetic torque represented by the upper half of the hyperbolic line with the broken line).

At any point (i) on the constant torque curve (curve of constant electromagnetic torque)_d0，i_q0) The normal vector of the curve can be represented as (i)_d0，i_q0+ B), as can be seen from the knowledge of the analytic geometry, as long as a straight line with a direction of a normal vector passes through the origin, the intersection point of the straight line and the constant torque curve is the tangent point of the stator current curve and the constant torque curve, at this time, under the same electromagnetic torque, the radius of the stator current curve is minimum, the distance from the tangent point on the constant torque curve to the origin is shortest, and under the same electromagnetic torque, I is the shortest_sIs the smallest, which is the corresponding point in the case of maximum torque to current ratio (MTPA). It can be seen that the point (i) on the constant torque curve that satisfies the maximum torque current ratio_d0，i_q0) Also on a straight line passing through the origin and oriented in the normal vector direction, this straight line can be expressed as the following formula (5).

The point (i) satisfying the maximum torque current ratio_d0，i_q0) Substituting into the above-described linear equation, the relationship of the following equation (6) can be obtained for all points satisfying the maximum torque current ratio.

The above equation (6) is a hyperbolic equation, and during the normal operation of the permanent magnet synchronous motor, the direct-axis current and the quadrature-axis current are both greater than 0, so only i in fig. 3 is concerned_dThe upper half of the axial forward direction is just needed.

It can be seen that the points at which the maximum torque to current ratio is satisfied satisfy both the above equation (4) and equation (6), so that for a given electromagnetic torque T_eWhen a vector control mode is selected, the solution can be used as the given value of the current inner loop, and finally corresponding current is sent out to realize the maximum torque current ratio control.

According to the derivation process, the equation (7) represents a geometric relationship between quadrature axis current and direct axis current in the permanent magnet synchronous motor and electromagnetic torque, that is, the equation (7) is a first mapping relationship, after the first electromagnetic torque of the permanent magnet synchronous motor is obtained, the first electromagnetic torque, a flux linkage of a permanent magnet in the permanent magnet synchronous motor, quadrature axis inductance and direct axis inductance are substituted into the equation (7), the quadrature axis current and the direct axis current can be solved, and the maximum torque-to-current ratio control can be performed on the permanent magnet synchronous motor by using the quadrature axis current and the direct axis current obtained through the solving.

According to the difference of the solution of the above equation (7), two methods for controlling the maximum torque current ratio of the permanent magnet synchronous motor based on the above equation (7) are provided as follows:

the first method is as follows: directly solving the formula (7) to obtain a target quadrature axis current and a target direct axis current so as to control the maximum torque current ratio of the permanent magnet synchronous motor;

the second method comprises the following steps: and (4) solving the formula (7) based on a PI regulator to obtain a target quadrature axis current and a target direct axis current so as to control the maximum torque current ratio of the permanent magnet synchronous motor.

Next, the two types of control methods for the maximum torque current ratio of the permanent magnet synchronous motor based on the formula (7) will be described.

In the first aspect, the method for controlling a maximum torque current ratio of a motor may include:

a1: acquiring a first electromagnetic torque required to be generated by a permanent magnet synchronous motor;

a2: calculating target quadrature axis current and target direct axis current according to the first electromagnetic torque and parameters such as flux linkage of a permanent magnet in the permanent magnet synchronous motor through the following equation set;

wherein i_qFor characterizing the target quadrature-axis current, i_dFor characterizing the target direct axis current, #_fIs used for representing the flux linkage of the permanent magnet in the permanent magnet synchronous motor, and Delta L is used for representing the difference between the quadrature axis inductance and the direct axis inductance of the permanent magnet synchronous motor, T_{e_ref}For characterizing a first electromagnetic torque, n_pThe device is used for representing the pole pair number of the permanent magnet synchronous motor;

a3: and controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current.

In the embodiment of the invention, aiming at a permanent magnet synchronous motor to be controlled, the equation set, parameters such as flux linkage of a permanent magnet in the permanent magnet synchronous motor, quadrature axis inductance, direct axis inductance, pole pair number and the like are stored in a motor control chip, in the process of controlling the permanent magnet synchronous motor to operate, a first electromagnetic torque required to be generated by the permanent magnet synchronous motor is transmitted to the motor control chip, then the motor control chip can solve a target quadrature axis current and a target direct axis current according to the received first electromagnetic torque and various parameters stored in advance, and further, the maximum torque current ratio control is carried out on the permanent magnet synchronous motor based on the solved target quadrature axis current and the target direct axis current.

In the embodiment of the invention, although the equation set is still a nonlinear relation between the quadrature-axis current and the direct-axis current and the electromagnetic torque, the equation set is simpler than the existing nonlinear equation set which needs to be solved based on an extreme value principle, so that the equation set can be solved in the controller to obtain the target quadrature-axis current and the target direct-axis current which meet the maximum torque-current ratio, the maximum torque-current ratio control of the permanent magnet synchronous motor is really realized, and the efficiency of the permanent magnet synchronous motor is improved.

As for the second mode, as shown in fig. 4, the method for controlling the maximum torque current ratio of the motor may include the steps of:

step 401: acquiring a first electromagnetic torque required to be generated by a permanent magnet synchronous motor;

step 402: acquiring a second electromagnetic torque, wherein the second electromagnetic torque is used for representing the electromagnetic torque referred to in the control process of the permanent magnet synchronous motor;

step 403: performing PI regulation by taking the difference between the first electromagnetic torque and the second electromagnetic torque as input to obtain a first quadrature axis current;

step 404: determining a first direct-axis current according to the first quadrature-axis current and a preset second geometric mapping relation, wherein the second geometric mapping relation is used for representing the geometric relation between the quadrature-axis current and the direct-axis current under the condition of the maximum torque-current ratio;

step 405: calculating a third electromagnetic torque according to the first quadrature axis current and the first direct axis current;

step 406: judging whether the third electromagnetic torque is equal to the first electromagnetic torque, if so, executing step 407, and if not, executing step 408;

step 407: determining the first quadrature axis current as a target quadrature axis current, determining the first direct axis current as a target direct axis current, and executing step 409;

step 408: taking the third electromagnetic torque as the second electromagnetic torque, and executing step 403;

step 409: and controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current.

In the embodiment of the invention, a second geometric relation between quadrature axis current and direct axis current under the condition of representing the maximum torque current ratio is preset, after the first electromagnetic torque and the second electromagnetic torque obtained by calculation are obtained, the difference between the first electromagnetic torque and the second electromagnetic torque is subjected to PI adjustment to obtain first quadrature axis current, then the first direct axis current is determined according to the obtained first quadrature axis current and the second geometric relation, and then the third electromagnetic torque is calculated according to the first quadrature axis current and the first direct axis current. If the third electromagnetic torque is equal to the first electromagnetic torque, the first quadrature-axis current and the first direct-axis current are points corresponding to the maximum torque-current ratio control, and then the first quadrature-axis current and the first direct-axis current are respectively determined as a target quadrature-axis current and a target direct-axis current to control the permanent magnet synchronous motor. If the third electromagnetic torque is different from the first electromagnetic torque, the first quadrature axis current and the first direct axis current are not points corresponding to the maximum torque current ratio control, and then PI regulation is continuously carried out on the third electromagnetic torque as the second electromagnetic torque to change the first quadrature axis current until the third electromagnetic torque equal to the first electromagnetic torque is obtained.

In the embodiment of the invention, PI regulation is carried out based on a first electromagnetic torque required to be generated by the permanent magnet synchronous motor, different first quadrature axis current and first direct axis current are generated to verify whether maximum torque current ratio control is met, the first quadrature axis current and the first direct axis current meeting the maximum torque current ratio control are gradually obtained, and the first quadrature axis current and the first direct axis current meeting the maximum torque current ratio control are respectively used as a target quadrature axis current and a target direct axis current to control the permanent magnet synchronous motor to operate. The PI regulator is used for carrying out PI regulation to obtain different first quadrature axis current and first direct axis current, the target quadrature axis current and the target direct axis current can be obtained through fast solving, and the speed of solving the target quadrature axis current and the target direct axis current can be greatly improved compared with a mode of directly solving a nonlinear equation set, so that engineering implementation is facilitated.

Optionally, on the basis of the method for controlling the maximum torque-to-current ratio of the motor shown in fig. 4, when step 404 determines the first direct current according to the first quadrature-axis current and the second geometric mapping relationship, parameters such as flux linkage of a permanent magnet in the permanent magnet synchronous motor, quadrature-axis inductance of the permanent magnet synchronous motor, direct-axis inductance of the permanent magnet synchronous motor, and the first quadrature-axis current may be substituted into the following first formula to calculate the first direct current;

the first formula includes:

wherein i_qFor characterizing the first quadrature-axis current, i_dFor characterizing the first direct current, #_fThe method is used for representing the flux linkage, and the Delta L is used for representing the difference between quadrature axis inductance and direct axis inductance.

In the embodiment of the present invention, after the first quadrature axis current is obtained through PI adjustment, the first quadrature axis current is substituted into the first formula (which is the second formula in the formula (7)), so as to calculate the first direct axis current corresponding to the first comparison axis current according to the geometric relationship that the quadrature axis current and the direct axis current satisfy under the condition of the maximum torque current ratio, and then verify whether the obtained first quadrature axis current and the obtained first direct axis current can enable the permanent magnet synchronous motor to generate the electromagnetic torque equal to the first electromagnetic torque, if the first quadrature axis current and the first direct axis current can enable the permanent magnet synchronous motor to generate the electromagnetic torque equal to the first electromagnetic torque, the first quadrature axis current and the first direct axis current are points corresponding to the maximum torque current ratio control under the first electromagnetic torque.

In the embodiment of the invention, the point which is located on the straight line passing through the origin and has the direction of the normal vector and the quadrature axis coordinate of which is the first quadrature axis current can be quickly determined by the first formula, and the direct axis coordinate of the point is the first direct axis current, so that the first quadrature axis current and the first direct axis current which possibly meet the control of the maximum torque current ratio can be quickly obtained, the target quadrature axis current and the target direct axis current which meet the control of the maximum torque current ratio can be quickly determined, and the permanent magnet synchronous motor can be accurately controlled in real time.

Alternatively, on the basis of calculating the first direct current by the first formula based on the above embodiment, when step 405 calculates the third electromagnetic torque according to the first quadrature axis current and the first direct current, the third electromagnetic torque may be calculated by substituting the number of pole pairs of the permanent magnet synchronous motor, the flux linkage of the permanent magnet, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current, and the second quadrature axis current into the following second formula;

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T_{e_calc}For characterizing the third electromagnetic torque, n_pNumber of pole pairs, L, for characterizing a permanent magnet synchronous machine_qFor characterizing quadrature inductance, L_dFor characterizing the direct axis inductance.

In the embodiment of the present invention, the obtained point corresponding to the first quadrature axis current and the first direct axis current is located on a straight line passing through the origin and having a direction in a normal vector direction, that is, the first quadrature axis current and the first direct axis current already satisfy another condition for realizing the maximum torque current ratio control, then the first quadrature axis current and the first direct axis current are substituted into the second formula to calculate the third electromagnetic torque, and if the calculated third electromagnetic torque is equal to the first electromagnetic torque, the first quadrature axis current and the first direct axis current satisfy all conditions for realizing the maximum torque current ratio control, and further the first quadrature axis current and the first direct axis current can be respectively determined as the target quadrature axis current and the target direct axis current, so as to realize the maximum torque current ratio control on the permanent magnet synchronous motor.

In the embodiment of the invention, after the first quadrature axis current and the first direct axis current are obtained, the electromagnetic torque which can be generated by the permanent magnet synchronous motor can be accurately calculated by the first quadrature axis current and the first direct axis current through the second formula, and then whether the electromagnetic torque which can be generated by the permanent magnet synchronous motor can be generated by the first quadrature axis current and the first direct axis current is determined.

In summary, for the method of performing the maximum torque current ratio control of the motor in the second mode, the control process is as shown in fig. 5, and the first electromagnetic torque T_{e_ref}And the calculated third electromagnetic torque T_{e_calc}The difference is PI regulated to obtain a first quadrature axis current i_qrefThe corresponding first direct current i can be quickly calculated through the calculation of the formula (6)_drefThen the obtained first quadrature axis current i is reused_qrefAnd a first direct current i_drefCalculating a third electromagnetic torque T by substituting into an electromagnetic torque formula_{e_calc}And using the calculated third electromagnetic torque T_{e_calc}And a first electromagnetic torque T_{e_ref}By comparison, when the third electromagnetic torque T_{e_calc}And a first electromagnetic torque T_{e_ref}When deviation exists, the PI regulator can automatically regulate the output first quadrature axis current i_qrefUntil a third electromagnetic torque T is applied_{e_calc}And a first electromagnetic torque T_{e_ref}The deviation therebetween is adjusted to zero, and finally the purpose of solving the equation set (equation (7)) is achieved.

Alternatively, on the basis of the motor maximum torque current ratio control method provided in each of the above embodiments, when the operation of the permanent magnet synchronous motor is controlled according to the target quadrature-axis current and the target direct-axis current, the operation of the permanent magnet synchronous motor may be controlled according to the difference between the target quadrature-axis current and the target direct-axis current and the actual quadrature-axis current and the actual direct-axis current of the permanent magnet synchronous motor. As shown in fig. 6, the method for controlling the operation of the permanent magnet synchronous motor according to the target quadrature-axis current and the target direct-axis current includes the following steps:

step 601: acquiring a second quadrature axis current and a second direct axis current, wherein the second quadrature axis current is used for representing the actual quadrature axis current of the permanent magnet synchronous motor, and the second direct axis current is used for representing the actual direct axis current of the permanent magnet synchronous motor;

step 602: taking the difference between the target quadrature axis current and the second quadrature axis current as an input to perform PI regulation to obtain a quadrature axis control signal;

step 603: taking the difference between the target direct axis current and the second direct axis current as input to carry out PI regulation to obtain a direct axis control signal;

step 604: and transmitting the quadrature axis control signal and the direct axis control signal to an inverter connected with the permanent magnet synchronous motor, so that the inverter transmits three-phase power to the permanent magnet synchronous motor according to the quadrature axis control signal and the direct axis control signal, the quadrature axis current of the permanent magnet synchronous motor is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor is equal to the target direct axis current.

In the embodiment of the invention, after a target quadrature axis current and a target direct axis current which meet the control of the maximum torque current ratio are determined, a second quadrature axis current for representing the actual quadrature axis current of the permanent magnet synchronous motor and a second direct axis current for representing the actual direct axis current of the permanent magnet synchronous motor are obtained, the difference between the target quadrature axis current and the second quadrature axis current is used as an input to perform PI regulation to obtain a quadrature axis control signal, the difference between the target direct axis current and the second direct axis current is used as an input to perform PI regulation to obtain a direct axis control signal, the quadrature axis control signal and the direct axis control signal are further sent to an inverter connected with the permanent magnet synchronous motor, the inverter controls the permanent magnet synchronous motor according to the quadrature axis control signal and the direct axis control signal, so that the quadrature axis current of the permanent magnet synchronous motor is stabilized at the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor is stabilized at the target direct axis current, thereby realizing the maximum torque current ratio control of the permanent magnet synchronous motor.

In the embodiment of the present invention, taking the maximum torque current ratio control of the motor in the second mode as an example, the process of controlling the operation of the permanent magnet synchronous motor according to the target quadrature-axis current and the target direct-axis current is shown in fig. 7, where the first electromagnetic torque T is_refAnd a second electromagnetic torque T_calcThe difference is adjusted by PI to obtain quadrature axis current i_qcalWill be quadrature axis current i_qcalSubstituting into formula (6) to calculate corresponding direct axis current i_dcalWill be quadrature axis current i_qcalAs a crossReference quadrature axis current i controlled by axis current loop_qrefUsing reference quadrature axis current i_qrefAnd the actual quadrature axis current i of the PMSM 702_qCurrent loop control is carried out, quadrature axis control signals obtained through PI regulation are transmitted to an inverter 701, and direct axis current i is obtained_dcalReference direct current i as direct current loop control_drefUsing a reference direct axis current i_drefAnd the actual direct axis current i of the permanent magnet synchronous machine 702_dAnd performing current loop control, obtaining a direct axis control signal through PI regulation, transmitting the direct axis control signal to the inverter 701, and controlling the permanent magnet synchronous motor 702 by the inverter 701 according to the quadrature axis control signal and the direct axis control signal to enable the actual quadrature axis current and the actual direct axis current of the permanent magnet synchronous motor 702 to approach the target quadrature axis current and the target direct axis current. In addition, the quadrature axis current i_qcalAnd a direct axis current i_dcalSubstituting into formula n_p[ψ_fi_q+(L_q-L_d)i_di_q]Calculating a second electromagnetic torque T_calcIf the second electromagnetic torque T_calcAnd a first electromagnetic torque T_refIf not, the quadrature axis current i is automatically adjusted_qcalAnd repeating the above process until the actual quadrature axis current and the actual direct axis current of the permanent magnet synchronous motor 702 are respectively equal to the target quadrature axis current and the target direct axis current, thereby realizing the maximum torque current ratio control of the permanent magnet synchronous motor 702.

In the process that the inverter 701 controls the permanent magnet synchronous motor 702 to operate, the sampling sensor 703 is used for collecting the three-phase current i of the permanent magnet synchronous motor 702_abcAnd rotor angle theta/omega, and then according to three-phase current i_abcAnd the rotor angle theta/omega is used for calculating a second quadrature axis current i_qAnd a second direct axis current i_d。

It should be noted that, in the motor maximum torque current ratio control method provided in each of the above embodiments, since it is easier to solve the target quadrature axis current and the target direct axis current, and it is not necessary to occupy a large amount of computing resources and storage space, the requirements for computing resources and storage space can be reduced on the premise of implementing the maximum torque current ratio control method, so that the cost for implementing the motor maximum torque current ratio control method can be reduced.

In addition, since the permanent magnet synchronous motor can be used as a generator as well as a motor, the maximum torque-current ratio control can be realized by the method provided by the embodiment of the invention when the permanent magnet synchronous motor is used as a motor or a generator. In the above embodiments, the permanent magnet synchronous motor is used as a generator, and the implementation of the maximum torque current ratio control is described in detail, because the current phases of the permanent magnet synchronous motor used as a motor and a generator are opposite, when the permanent magnet synchronous motor used as a motor, only i in the above formula in the above embodiments needs to be used_qIs replaced by-i_qAnd will i_dIs replaced by-i_dThat is, the method for realizing the maximum current ratio control when the permanent magnet synchronous motor is used as a motor will not be described herein.

As shown in fig. 8, an embodiment of the present invention provides a maximum torque current ratio control apparatus for a motor, including:

a torque obtaining module 81, configured to obtain a first electromagnetic torque, where the first electromagnetic torque is used to characterize an electromagnetic torque required to be generated by the permanent magnet synchronous motor;

a current obtaining module 82, configured to determine a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque obtained by the torque obtaining module 81 and a preset first mapping relationship, where the first mapping relationship is used to represent a geometric relationship between the quadrature-axis current and the direct-axis current in the permanent magnet synchronous motor and the electromagnetic torque;

and the motor control module 83 is used for controlling the permanent magnet synchronous motor to operate according to the target quadrature axis current and the target direct axis current acquired by the current acquisition module 82.

In an embodiment of the present invention, the torque acquisition module 81 and the voltage detection module 402 may be configured to perform step 101, the current acquisition module 82 may be configured to perform step 102, and the motor control module 83 may be configured to perform step 103.

Alternatively, on the basis of the motor maximum torque current ratio control device shown in fig. 8,

the current acquisition module 82 is used for calculating a target quadrature-axis current and a target direct-axis current according to the first electromagnetic torque and the flux linkage of the permanent magnet in the permanent magnet synchronous motor through the following equation set;

wherein i_qFor characterizing the target quadrature-axis current, i_dFor characterizing the target direct axis current, #_fFor characterizing the flux linkage, DeltaL for characterizing the difference between the quadrature and direct inductances, T, of the PMSM_{e_ref}For characterizing a first electromagnetic torque, n_pThe method is used for representing the pole pair number of the permanent magnet synchronous motor.

Alternatively, on the basis of the motor maximum torque current ratio control apparatus shown in fig. 8, as shown in fig. 9, the current acquisition module 82 includes:

a first obtaining unit 821, configured to obtain a second electromagnetic torque, where the second electromagnetic torque is used to represent an electromagnetic torque referred to in a control process of the permanent magnet synchronous motor;

a first PI adjustment unit 822, configured to perform PI adjustment using a difference between the first electromagnetic torque and the second electromagnetic torque acquired by the first acquisition unit 821 as an input to obtain a first quadrature axis current;

a first calculating unit 823, configured to determine a first direct current according to the first quadrature axis current obtained by the first PI adjusting unit 822 and a preset second geometric mapping relationship, where the second geometric mapping relationship is used to represent a geometric relationship between the quadrature axis current and the direct axis current under a maximum torque-to-current ratio condition;

a second calculating unit 824, configured to calculate a third electromagnetic torque according to the first quadrature axis current obtained by the first PI adjusting unit 822 and the first direct axis current obtained by the first calculating unit 823;

a determination unit 825 configured to determine whether the third electromagnetic torque calculated by the second calculation unit 824 is equal to the first electromagnetic torque acquired by the torque acquisition module 81;

a current mapping unit 826 for determining the first quadrature-axis current as a target quadrature-axis current and the first direct-axis current as a target direct-axis current when the determination unit 825 determines that the third electromagnetic torque is equal to the first electromagnetic torque;

and a torque mapping unit 827, configured to, when the determining unit 825 determines that the third electromagnetic torque is not equal to the first electromagnetic torque, use the third electromagnetic torque as the second electromagnetic torque, and trigger the first PI adjusting unit 822 to perform PI adjustment by using a difference between the first electromagnetic torque and the second electromagnetic torque as an input, so as to obtain a first quadrature axis current.

In the embodiment of the present invention, the first obtaining unit 821 may be configured to execute the step 402 in the above-described method embodiment, the first PI adjustment unit 822 may be configured to execute the step 403 in the above-described method embodiment, the first calculating unit 823 may be configured to execute the step 404 in the above-described method embodiment, the second calculating unit 824 may be configured to execute the step 405 in the above-described method embodiment, the determining unit 825 may be configured to execute the step 406 in the above-described method embodiment, the current mapping unit 826 may be configured to execute the step 408 in the above-described method embodiment, and the torque mapping unit 827 may be configured to execute the step 408 in the above-described method embodiment.

Alternatively, on the basis of the motor maximum torque current ratio control device shown in fig. 8,

the first calculating unit 823 is configured to calculate a first direct current according to a first formula as follows according to a flux linkage of a permanent magnet in the permanent magnet synchronous motor, a quadrature axis inductance and a direct axis inductance of the permanent magnet synchronous motor, and the first quadrature axis current;

the first formula includes:

wherein i_qFor characterizing the first quadrature-axis current, i_dFor characterizing the first direct current, #_fThe method is used for representing the flux linkage, and the Delta L is used for representing the difference between quadrature axis inductance and direct axis inductance.

Alternatively, on the basis of the motor maximum torque current ratio control device shown in fig. 8,

a second calculating unit 824, configured to calculate a third electromagnetic torque according to the following second formula according to the pole pair number, the flux linkage, the quadrature axis inductance, the direct axis inductance, the first quadrature axis current, and the first direct axis current of the permanent magnet synchronous motor;

the second formula includes:

T_{e_calc}＝n_p[ψ_fi_q+(L_q-L_d)i_di_q]

wherein, T_{e_calc}For characterizing the third electromagnetic torque, n_pNumber of pole pairs, L, for characterizing a permanent magnet synchronous machine_qFor characterizing quadrature inductance, L_dFor characterizing the direct axis inductance.

Alternatively, on the basis of the motor maximum torque current ratio control device provided in any of the above embodiments, as shown in fig. 10, the motor control module 83 includes:

a second obtaining unit 831, configured to obtain a second quadrature-axis current and a second direct-axis current, where the second quadrature-axis current is used to represent an actual quadrature-axis current of the permanent magnet synchronous motor, and the second direct-axis current is used to represent an actual direct-axis current of the permanent magnet synchronous motor;

a second PI adjusting unit 832, configured to perform PI adjustment using a difference between the target quadrature axis current and the second quadrature axis current obtained by the second obtaining unit 831 as an input, so as to obtain a quadrature axis control signal;

a third PI adjustment unit 833, configured to perform PI adjustment using a difference between the target direct axis current and the second direct axis current obtained by the second obtaining unit 831 as an input, so as to obtain a direct axis control signal;

a signal transmission unit 834, configured to transmit the quadrature axis control signal obtained by the second PI adjustment unit 832 and the direct axis control signal obtained by the third PI adjustment unit 833 to an inverter connected to the permanent magnet synchronous motor, so that the inverter transmits three-phase power to the permanent magnet synchronous motor according to the quadrature axis control signal and the direct axis control signal, so that the quadrature axis current of the permanent magnet synchronous motor is equal to the target quadrature axis current, and the direct axis current of the permanent magnet synchronous motor is equal to the target direct axis current.

In the embodiment of the present invention, the second obtaining unit 831 may be configured to perform step 601 in the foregoing method embodiment, the second PI adjusting unit 832 may be configured to perform step 602 in the foregoing method embodiment, the third PI adjusting unit 833 may be configured to perform step 603 in the foregoing method embodiment, and the signal transmitting unit 834 may be configured to perform step 604 in the foregoing method embodiment.

It should be noted that the motor maximum torque current ratio control device provided in each of the above embodiments and the motor maximum torque current ratio control method are based on the same concept, and the interaction between the modules in the motor maximum torque current ratio control device may refer to the description in the foregoing motor maximum torque current ratio control method embodiment, and will not be described again here.

As shown in fig. 11, an embodiment of the present invention provides a maximum torque current ratio control apparatus for a motor, including: at least one memory 84 and at least one processor 85;

the at least one memory 84 for storing a machine readable program;

the at least one processor 85 is configured to invoke the machine readable program to execute the method for controlling the maximum torque current ratio of the motor provided in the foregoing embodiments.

The present invention also provides a computer readable medium storing instructions for causing a computer to perform a method of controlling a maximum torque to current ratio of an electric machine as described herein. Specifically, a system or an apparatus equipped with a storage medium on which software program codes that realize the functions of any of the above-described embodiments are stored may be provided, and a computer (or a CPU or MPU) of the system or the apparatus is caused to read out and execute the program codes stored in the storage medium.

In this case, the program code itself read from the storage medium can realize the functions of any of the above-described embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

Examples of the storage medium for supplying the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (e.g., CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW), a magnetic tape, a nonvolatile memory card, and a ROM. Alternatively, the program code may be downloaded from a server computer via a communications network.

Further, it should be clear that the functions of any one of the above-described embodiments may be implemented not only by executing the program code read out by the computer, but also by causing an operating system or the like operating on the computer to perform a part or all of the actual operations based on instructions of the program code.

Further, it is to be understood that the program code read out from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion unit connected to the computer, and then causes a CPU or the like mounted on the expansion board or the expansion unit to perform part or all of the actual operations based on instructions of the program code, thereby realizing the functions of any of the above-described embodiments.

It should be noted that not all steps and modules in the above flows and system structure diagrams are necessary, and some steps or modules may be omitted according to actual needs. The execution order of the steps is not fixed and can be adjusted as required. The system structure described in the above embodiments may be a physical structure or a logical structure, that is, some modules may be implemented by the same physical entity, or some modules may be implemented by a plurality of physical entities, or some components in a plurality of independent devices may be implemented together.

In the above embodiments, the hardware unit may be implemented mechanically or electrically. For example, a hardware element may comprise permanently dedicated circuitry or logic (such as a dedicated processor, FPGA or ASIC) to perform the corresponding operations. The hardware elements may also comprise programmable logic or circuitry, such as a general purpose processor or other programmable processor, that may be temporarily configured by software to perform the corresponding operations. The specific implementation (mechanical, or dedicated permanent, or temporarily set) may be determined based on cost and time considerations.

While the invention has been shown and described in detail in the drawings and in the preferred embodiments, it is not intended to limit the invention to the embodiments disclosed, and it will be apparent to those skilled in the art that various combinations of the code auditing means in the various embodiments described above may be used to obtain further embodiments of the invention, which are also within the scope of the invention.