WO2022134772A1

WO2022134772A1 - Control method for permanent magnet auxiliary synchronous reluctance motor

Info

Publication number: WO2022134772A1
Application number: PCT/CN2021/124417
Authority: WO
Inventors: 柴璐军; 张瑞峰; 杨高兴; 秦小霞; 蔡晓; 詹哲军
Original assignee: 中车永济电机有限公司
Priority date: 2020-12-25
Filing date: 2021-10-18
Publication date: 2022-06-30
Also published as: CN112737441B; CN112737441A

Abstract

Provided is control method for a motor, and in particular a control method for a permanent magnet auxiliary synchronous reluctance motor, which solves the technical problems in which the torque pulsation outputted by a permanent magnet auxiliary synchronous reluctance motor is large and existing control strategies must consider in real time changes in Ld, Lq and ψf to be able to ensure the precision of the outputted torque. The effect of motor temperature change and motor saturation effect on parameters of the permanent magnet auxiliary synchronous reluctance motor is considered at the same time, and the accuracy of the parameters of the motor at each working point is improved by inquiring quadrature axis and direct axis flux linkages ψd and ψq. The present control method enables the permanent magnet auxiliary synchronous reluctance motor to still maintain high control precision under a wide environment condition. In the present control method, the torque pulsation outputted by a motor may be reduced by inhibiting main subharmonic content in a motor current, improving the stability of torque output, and the inherent defect in which torque pulsation is large when a permanent magnet auxiliary synchronous reluctance motor operates may be solved.

Description

A control method of permanent magnet assisted synchronous reluctance motor

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is based on a Chinese patent application with an application number of 202011566496.0 and an application date of December 25, 2020, and claims the priority of the Chinese patent application, the entire contents of which are hereby incorporated by reference into the present application.

technical field

The present disclosure belongs to a permanent magnet assisted synchronous reluctance motor, and relates to a control method of the motor, in particular to a control method of a permanent magnet assisted synchronous reluctance motor.

Background technique

The permanent magnet assisted synchronous reluctance motor is a new type of motor with less rare earth consumption and high reluctance torque. Compared with the permanent magnet synchronous motor, the permanent magnet assisted synchronous reluctance motor can reduce the amount of permanent magnets and significantly reduce the speed of the motor during high-speed operation. Back EMF, make full use of reluctance torque, and run more safely and reliably; at the same time, permanent magnet-assisted synchronous reluctance motors have significant advantages such as high power density, high efficiency, wide speed regulation range, small size and light weight, etc. It is more suitable to replace the original asynchronous motor as a traction motor for diesel locomotives. The obvious defect of the permanent magnet assisted synchronous reluctance motor is that the output torque ripple is large. In the control strategy of the permanent magnet assisted synchronous reluctance motor, the suppression of the torque ripple must be considered to make the output torque of the motor as stable as possible; Influenced by the structural design of the motor rotor, the magnetic circuit is more prone to saturation of the magnetic circuit. The inductance values L _q and L _d of the AC and DC axes are affected by the currents i _q and _id of the AC and DC axes, and L _q and L _d are also significantly affected by the temperature of the motor; The rotor flux linkage ψ _f is affected by temperature and current amplitude, and is not a constant value, and is usually set as a constant value in the existing control strategy, so the existing control strategy should consider the L _d , L _q , ψ _f in real time. change to ensure the accuracy of the output torque.

SUMMARY OF THE INVENTION

In view of this, the present disclosure aims to solve the technical problems that the output torque ripple of the permanent magnet assisted synchronous reluctance motor is large and the existing control strategy needs to consider the changes of L _d , L _q and ψ _f in real time to ensure the accuracy of the output torque. , a control method of a permanent magnet assisted synchronous reluctance motor is provided.

The technical means adopted by the present disclosure to solve the technical problems are: a control method of a permanent magnet assisted synchronous reluctance motor, which adopts a temperature sensor, a current sensor, a resolver, a Clark transformation module, a Park transformation module, a torque command processing module, MTPA look-up module, AC-direct-axis flux linkage look-up module, voltage calculation module, harmonic current suppression module and pulse modulation module;

The temperature sensor is fixed on the stator of the permanent magnet auxiliary synchronous reluctance motor, and the temperature sensor collects the stator temperature T of the permanent magnet auxiliary synchronous reluctance motor in real time;

The current sensor is configured to collect two-phase currents i _a and i _b of the permanent magnet assisted synchronous reluctance motor;

The resolver is configured to collect the rotor position θ of the permanent magnet assisted synchronous reluctance motor, and after the rotor position θ is differentiated, the rotational speed we of the permanent magnet assisted synchronous _reluctance motor is obtained;

The two-phase currents i _a and i _b of the permanent magnet assisted synchronous reluctance motor are processed by the Clark transformation module to obtain the stator currents i _α and i _β , and the stator currents i _α and i _β are processed by the Park transformation module to obtain the dq rotating coordinate system The current _id and i _q under ;

The input of the torque command processing module is the target torque T _e , which is derived from the vehicle control unit VCU _{, and the target torque T e} _is processed by the limit and torque ramp of the torque command processing module to obtain the given torque T _e *;

The given torque T _e * is input to the MTPA table look-up module, and after the MTPA table look-up module is processed according to the calibrated maximum torque-current ratio strategy, the direct-axis command current i ^* _d and the quadrature-axis command current i ^* _q are output;

The input of the direct-axis flux linkage look-up table module is the direct-axis command current i ^* _d , the quadrature-axis command current _i ^* _q and the stator temperature _T of the ^motor ^. The motor stator temperature T performs a look-up table interpolation algorithm in real time, and firstly obtains the direct-axis flux linkage that changes with i ^* _d and i ^* _q

and quadrature flux linkage

Secondly, the flux linkage value is obtained based on the real-time motor temperature

and

That is, the output of the quadrature-axis flux linkage look-up table module;

The voltage calculation module consists of a feedforward voltage module and a current regulator module; the input of the feedforward voltage module is

and w _e ; the outputs of the feedforward voltage module are u _dfw and u _qfw ; ignoring the electronic resistance, the calculation formulas of u _dfw and u _qfw are shown in formula (1):

The input to the current regulator block is

_id and i _q , the outputs of the current regulator module are Δu _d and Δu _q ;

Form a first closed-loop PI regulator with _id , and the output of the first closed-loop PI regulator is _Δud ,

A second closed-loop PI regulator is formed with i _q , and the output of the second closed-loop PI regulator is Δu _q ;

The output of the voltage calculation module is the direct-axis command voltage _ud and the quadrature-axis command voltage u _q , and the calculation formula is shown in the following formula (2):

The inputs of the harmonic current suppression module are i ^* _d5th , i ^* _q5th , i ^* _d7th , i ^* _q7th , i _d5th , i _q5th , i _d7th , and i _q7th ; the outputs of the harmonic current suppression module are u _a5-7th , u _b5-7th , u _c5-7th ; the harmonic current suppression module includes a current extraction module, a current harmonic suppression adjustment module and a voltage conversion module;

The control method adopts feedforward decoupling control, injects corresponding harmonic voltage components into the three-phase voltage to offset the harmonics in the motor current, obtains high harmonic content of the 5th and 7th times through fast Fourier transform, and obtains high harmonic content through the current extraction module. To obtain the three-phase current of the permanent magnet-assisted synchronous reluctance motor during operation, Clark and Park transformations are firstly performed under the 5th and 7th synchronous rotation coordinates, because the 5th and 7th harmonic currents can generate direct currents under the corresponding number of coordinate system transformations. Therefore, the low-pass filter can filter out the AC signal in the DC signal, and extract the i _d5th , i _q5th , i _d7th , i _q7th signals;

The i _d5th , i _q5th , i _d7th , i _q7th signals are input to the current harmonic suppression adjustment module as the feedback link, and the current harmonic suppression adjustment module outputs the corresponding harmonic voltage components u _d5th , u _q5th , u _d7th , u _q7th , because It is expected that the 5th and 7th harmonic currents are zero, so the given i ^* _d5th , i ^* _q5th , i ^* _d7th , i ^* _q7th of the current harmonic suppression regulator are 0, and the current harmonic suppression regulator is calculated by the following formula u _d5th and u _q5th , u _d7th and u _q7th respectively formula (3), formula (4) are as follows:

where k _pd5th , k _pq5th , k _id5th and k _iq5th are the control parameters of the 5th harmonic current suppression module, respectively, and their values are adjusted based on engineering experience, where k _pd7th , k _pq5th , k _id7th , and k _iq7th are respectively 7 The control parameters of the sub-harmonic current suppression module are adjusted based on engineering experience;

u _d5th , u _q5th and u _d7th , u _q7th are respectively superimposed to generate u _a5-7th , u _b5-7th , u _c5-7th after performing inverse Clark transformation and inverse Park transformation through the voltage transformation module;

The input of the pulse modulation module is u _a *, u _b * and u _c *, u _a *, u _b * and u _c * are the outputs of _ud and u _q after inverse Park and inverse Clark transformation, u _a , u _b , _{uc is generated by superimposing the output u a5-7th, u b5-7th, u c5-7th} _of _the _harmonic current suppression module; the output of the pulse modulation module is the conduction time T _a , T _b of the three-phase inverter bridge IGBT and T _c , the IGBT is turned on to drive the motor to run.

The present disclosure also considers the influence of motor temperature change and motor saturation effect on the parameters of the permanent magnet assisted synchronous reluctance motor, and improves the accuracy of the parameters of the motor at each operating point by querying the quadrature axis flux linkage ψ _d and ψ _q . The method enables the permanent magnet-assisted synchronous reluctance motor to maintain high control accuracy under a wide range of environmental conditions; the control method described in the present disclosure can reduce the torque ripple of the motor output by suppressing the main harmonic content in the motor current , improve the stability of the torque output, and can solve the inherent defect of the permanent magnet-assisted synchronous reluctance motor with large torque ripple during operation; as an optimization control method of the permanent-magnet-assisted synchronous reluctance motor, the present disclosure can promote the permanent-magnet-assisted synchronous reluctance motor. The popularization and application of reluctance motor.

Description of drawings

FIG. 1 is an overall control block diagram of a method for controlling a permanent magnet assisted synchronous reluctance motor described in the present disclosure.

FIG. 2 is a synchronously rotating coordinate system according to the present disclosure.

FIG. 3 is a flow chart of the orthogonal-direct-axis flux linkage look-up table according to the present disclosure.

FIG. 4 is a control diagram of the current extraction module of the present disclosure.

FIG. 5 is a control block diagram of the fifth-order current harmonic suppression adjustment module according to the present disclosure.

FIG. 6 is a control block diagram of the seventh-order current harmonic suppression adjustment module according to the present disclosure.

FIG. 7 is a block diagram of a multi-mode modulation strategy of the pulse modulation module of the present disclosure.

Detailed ways

1 to 7 , a method for controlling a permanent magnet assisted synchronous reluctance motor described in the present disclosure will be described in detail.

A control method of a permanent magnet assisted synchronous reluctance motor, as shown in Figure 1, adopts a temperature sensor, a current sensor, a resolver, a Clark transformation module, a Park transformation module, a torque command processing module, an MTPA look-up table module, an AC-DC Shaft flux linkage look-up table module, voltage calculation module, harmonic current suppression module and pulse modulation module;

The temperature sensor is fixed on the stator of the permanent magnet assisted synchronous reluctance motor, and the temperature sensor collects the stator temperature T of the permanent magnet assisted synchronous reluctance motor in real time; the acquisition method of the stator temperature T of the permanent magnet assisted synchronous reluctance motor is as follows: In the drag test environment, make the permanent magnet auxiliary synchronous reluctance motor run at the rated speed, load the motor under test, and test the temperature of the motor winding or iron core with the temperature sensor, as the inductance ambient temperature, at [-20℃, 160℃] The interval motor is tested once every 10°C rise. When the motor temperature value is stable, the temperature recorded at this moment is the temperature T of the stator of the permanent magnet assisted synchronous reluctance motor. In the interval [-20°C, 160°C], a total of nineteen test temperature point;

The given torque T _e * is input to the MTPA table look-up module. After the MTPA table look-up module is processed according to the calibrated maximum torque-current ratio strategy, the direct-axis command current i ^* _d and the quadrature-axis command current i ^* _q are output; specifically, MTPA The MTPA table in the table look-up module is implemented by a calibration method, which includes, for each current amplitude is, setting the interval of is to [0, _imax ], _where _imax is the maximum phase current _of the motor, and the current vector The interval of angle β is [90°, 180°], the step size of is is set to 0.25 times of _i _max , and the step size of current vector angle β is set to 1°, for each is according to formula ( ₅ ) Calculate i ^* _d and i ^* _q :

The host computer gives different d and q axis currents i ^* _d and i ^* _q , and adjusts the PI parameters of the first closed-loop PI regulator and the second closed-loop PI regulator respectively. When the d and q axis currents achieve good follow-up, record T _e and the output values _ud and u _q of the voltage calculation module; find the different combinations under each is _s

The maximum torque T _emax corresponding to the torque, and then the maximum torque-current ratio curve is fitted by the T _emax value corresponding to _each is to construct T _emax respectively with

The one-dimensional table of the MTPA module is written in the program in the form of a one-dimensional array as the table lookup basis of the MTPA module;

and quadrature flux linkage

and

It is the output of the quadrature-axis flux linkage look-up module; the quadrature-axis flux linkage table can be obtained through the bench experiment. The method of obtaining the table in the bench experiment is as follows: At each test temperature point, different d-axis are given by the host computer. Current id and q-axis current i _q , respectively adjust the PI parameters of the first closed-loop PI regulator and the second closed-loop PI regulator, when the _d -axis current _id and q-axis current _i _q achieve good follow-up, record Te and The output values _ud and u _q of the voltage calculation module, and then R _s , ψ _d , and ψ _q are calculated by formula (6), and formula (6) is specifically:

Record the parameters obtained from the test, and draw the two-dimensional tables of ψ _d and ψ _q about the _d -axis current id and q-axis current i _q , respectively. For each test temperature point, there is a two-dimensional table of ψ _d and one of ψ _q . Two-dimensional table; several two-dimensional tables of ψ _d and ψ _q are written in the program in the form of two-dimensional arrays for table look-up; the method of looking up the table of orthogonal axis flux linkage parameters is as follows, see Figure 3 for details: real-time acquisition of temperature sensors The temperature T of the stator, each real-time acquisition temperature T, corresponds to two look-up table temperatures T _s and T _s+10 , T _s and T _s+10 are two phases in the interval [-20°C, 160°C]. Adjacent test temperature point, T is a value in the interval [T _s , T _s+10 ], the relationship between T _s+10 and T _s is: T _S+10 =T _S +10, where T _s is 10 Integer multiples, and the value range of T _s is [-20°C, 160°C]; for each table look-up temperature T _s , there is a two-dimensional table of ψ _d on i _q and _id and a ψ _q on i Two-dimensional table of _q and _id ; wherein the table look-up interval of i _q and id is set to 0.05 times of the maximum current _; at each table look-up temperature T _s , the real-time values of ψ _d and ψ _q are determined by the time The _i ^* _d and _i ^* _q output by the MTPA look-up table module are obtained by two-dimensional linear interpolation based on the two-dimensional table of ψ _d and ψ _q parameters. parameters ψ _d ( _id , i _q , T _s ), ψ _d ( _id , i _q , T _s+10 ), and two parameters of the q-axis flux linkage ψ _q ( _id , i _q , T _s ) ), ψ _q (id , i _q , T _s+10 ), then ψ _d ( _id , i _q , T _s ) and ψ _d ₍ _id , i _q , T _s+10 ), ψ _q (i _d , i _q , T _s ) and ψ _q ( _id , i _q , T _s+10 ) perform one-dimensional linear interpolation with respect to the temperature T _s and T _s+10 respectively according to the real-time collected temperature T to obtain the direct-axis flux linkage The value ψ _d ( _id , i _q , T) and the quadrature axis flux linkage value ψ _q ( _id , i _q , T); in the calculation of the quadrature axis flux linkage look-up table module, ψ _d , ψ _q and the motor parameter L _d , L _q , ψ _f have the following relationship, which is expressed as formula (7):

The input to the current regulator block is

The control method adopts feedforward decoupling control, injects corresponding harmonic voltage components into the three-phase voltage to offset the harmonics in the motor current, and obtains high harmonic content of the 5th and 7th order through fast Fourier transform, and rotates the coordinate system synchronously. As shown in Figure 2, the rotation direction of the 5th harmonic voltage is opposite to the rotation direction of the fundamental wave vector, and the angular velocity is 5 times that of the fundamental wave. In addition, the permanent magnet-assisted synchronous reluctance motors of different powers may contain different harmonic contents of different frequencies. Therefore, the harmonic orders that can be suppressed by the harmonic current suppression module in the present disclosure can be extended to 5, 7, 11, 13 order; therefore, the three-phase current expression including the 5th and 7th harmonics is shown in equation (8):

In formula (8), i ₁ is the amplitude of the fundamental wave, i ₅ is the amplitude of the 5th current harmonic, i ₇ is the amplitude of the 7th current harmonic,

are the initial phases, respectively;

The rotating coordinate system of the 5th harmonic component and the 7th harmonic component is established. According to the principle of Clark and Park transformation, equal-amplitude transformation is adopted. The flow rate is DC in this coordinate system. Therefore, the 5th harmonic current component is a DC amount in the 5th harmonic d-q synchronous rotating coordinate system, and the 7th harmonic current component is in the 7th harmonic d-q synchronous rotating coordinate system. is the direct current;

The steady-state voltage equation of the fifth harmonic in the d-q synchronous rotating coordinate system of the fifth harmonic is equation (9):

In formula (9), u _d5th and u _q5th are the d and q-axis voltage values of the 5th harmonic voltage in the 5th synchronous coordinate, respectively, where i _d5th and i _q5th are the 5th harmonic current in the 5th synchronous coordinate, respectively. d and q-axis current values below;

The steady-state voltage equation of the seventh harmonic in the d-q synchronous rotating coordinate system of the seventh harmonic is equation (10):

In formula (10), u _d7th and u _q7th are the d and q-axis voltage values of the 7th harmonic voltage at the 7th synchronous coordinate, respectively, where i _d7th and i _q7th are the 7th harmonic current at the 7th synchronous coordinate, respectively. d and q-axis current values below;

The three-phase current of the permanent magnet-assisted synchronous reluctance motor during operation is obtained through the current extraction module. First, Clark and Park transformations are performed under the 5th and 7th synchronous rotation coordinates. The DC quantity can be generated under the condition, and the other sub-harmonic components are still the AC quantity after transformation, so the AC signal in the DC signal can be filtered out through a low-pass filter, and the _id5th , i _q5th , _id7th , and i _q7th signals can be extracted, such as As shown in Figure 4;

The i _d5th , i _q5th , i _d7th , i _q7th signals are input to the current harmonic suppression adjustment module as the feedback link, and the current harmonic suppression adjustment module outputs the corresponding harmonic voltage components u _d5th , u _q5th , u _d7th , u _q7th , because It is expected that the 5th and 7th harmonic currents are zero, so the given i ^* _d5th , i ^* _q5th , i ^* _d7th , i ^* _q7th of the current harmonic suppression regulator are 0, and the current harmonic suppression regulator is calculated by the following formula u _d5th and u _q5th , u _d7th and u _q7th respectively formula (3), formula (4) are as follows, as shown in Figure 5 and Figure 6:

where k _pd5th , k _pq5th , k _id5th and k _iq5th are the control parameters of the 5th harmonic current suppression module, respectively, and their values are adjusted based on engineering experience, where k _pd7th , k _pq5th , k _id7th , and k _iq7th are respectively 7 The control parameters of the sub-harmonic current suppression module are adjusted based on engineering experience; when the current harmonic suppression adjustment module calculates the harmonic voltage components u _d5th and u _q5th , first adjust k _pd5th and k _pq5th , and then adjust k _id5th , The initial values of k _iq5th , k _pd5th and k _pq5th are set to 1.0, and the initial values of k _id5th and k _iq5th are set to 10; when the current harmonic suppression adjustment module calculates the harmonic voltage components u _d7th and u _q7th , it first adjusts the k _pd7th and k _pq7th , and then adjust k _id7th and k _iq7th . The initial values of k _pd5th and k _pq7th are set to 1.0, and the initial values of k _id7th and k _iq7th are set to 10;

u _d5th , u _q5th and u _d7th , u _q7th respectively perform inverse Clark transformation and inverse Park transformation through the voltage transformation module to generate u _a5-7th , u _b5-7th and u _c5-7th ; The angle used by Park transform is -5θ, and the angle used by the inverse Park transform of the 7th harmonic voltage component is 7θ;

The input of the pulse modulation module is u _a *, u _b * and u _c *, u _a *, u _b * and u _c * are the outputs of _ud and u _q after inverse Park and inverse Clark transformation, u _a , u _b and uc are generated by superimposing the outputs u _a5-7th , u _b5-7th and u _c5-7th of the harmonic current suppression module; the calculation formulas of u _a , _ub and uc are formula ₍ 11 ₎ :

The output of the pulse modulation module is the conduction time T _a , T _b and T _c of the three-phase inverter bridge IGBT. The IGBT is turned on to drive the motor to run. The diesel locomotive traction system belongs to a high-power electric drive system. High current, the peak power of the motor reaches 700kW. Due to the limitation of heat dissipation conditions, the maximum switching frequency of IGBT is only 750Hz, but the output frequency of the inverter can be as high as 200Hz. The traditional svpwm modulation algorithm cannot meet the demand, and the modulation algorithm adopts multi-mode The modulation strategy, as shown in Figure 7, is to use asynchronous modulation when the motor frequency is [0～30Hz), synchronous modulation when the motor frequency is [30～62Hz), and intermediate when the motor frequency is [62～90Hz). 60 degree modulation, when the motor frequency is in [90Hz～200Hz], square wave control is adopted.

The above specific structure is a specific description of the preferred embodiment of the present disclosure, but the invention of the present disclosure is not limited to the embodiment, and those skilled in the art can make various equivalents without departing from the spirit of the present disclosure. Modifications or substitutions, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present application.

Claims

A control method for a permanent magnet assisted synchronous reluctance motor, which adopts a temperature sensor, a current sensor, a resolver, a Clark transformation module, a Park transformation module, a torque command processing module, an MTPA look-up table module, and an A/C-axis flux linkage look-up table module. , voltage calculation module, harmonic current suppression module and pulse modulation module;

The temperature sensor is fixed on the stator of the permanent magnet auxiliary synchronous reluctance motor, and the temperature sensor collects the stator temperature T of the permanent magnet auxiliary synchronous reluctance motor in real time;

The current sensor is configured to collect two-phase currents i a and i b of the permanent magnet assisted synchronous reluctance motor;

The resolver is configured to collect the rotor position θ of the permanent magnet assisted synchronous reluctance motor, and after the rotor position θ is differentiated, the rotational speed we of the permanent magnet assisted synchronous reluctance motor is obtained;

The two-phase currents i a and i b of the permanent magnet assisted synchronous reluctance motor are processed by the Clark transformation module to obtain the stator currents i α and i β , and the stator currents i α and i β are processed by the Park transformation module to obtain the dq rotating coordinate system The current id and i q under ;

The input of the torque command processing module is the target torque T e , which is derived from the vehicle control unit VCU , and the target torque T e is processed by the limit and torque ramp of the torque command processing module to obtain the given torque T e *;

The given torque T e * is input to the MTPA table look-up module, and after the MTPA table look-up module is processed according to the calibrated maximum torque-current ratio strategy, the direct-axis command current i * d and the quadrature-axis command current i * q are output;

The input of the direct-axis flux linkage look-up table module is the direct-axis command current i * d , the quadrature-axis command current i * q and the stator temperature T of the motor . The motor stator temperature T performs a look-up table interpolation algorithm in real time, and firstly obtains the direct-axis flux linkage that changes with i * d and i * q
and quadrature flux linkage
Secondly, the flux linkage value is obtained based on the real-time motor temperature
and

and
That is, the output of the quadrature-axis flux linkage look-up table module;

The voltage calculation module consists of a feedforward voltage module and a current regulator module; the input of the feedforward voltage module is
and w e ; the outputs of the feedforward voltage module are u dfw and u qfw ; ignoring the electronic resistance, the calculation formulas of u dfw and u qfw are shown in formula (1):

The input to the current regulator module is
id and i q , the outputs of the current regulator module are Δu d and Δu q ;
Form a first closed-loop PI regulator with id , and the output of the first closed-loop PI regulator is Δud ,
A second closed-loop PI regulator is formed with i q , and the output of the second closed-loop PI regulator is Δu q ;

The output of the voltage calculation module is the direct-axis command voltage ud and the quadrature-axis command voltage u q , and the calculation formula is shown in the following formula (2):

The inputs of the harmonic current suppression module are i * d5th , i * q5th , i * d7th , i * q7th , i d5th , i q5th , i d7th , and i q7th ; the outputs of the harmonic current suppression module are u a5-7th , u b5-7th , u c5-7th ; the harmonic current suppression module includes a current extraction module, a current harmonic suppression adjustment module and a voltage conversion module;

The control method adopts feedforward decoupling control, injects corresponding harmonic voltage components into the three-phase voltage to offset the harmonics in the motor current, obtains high harmonic content of the 5th and 7th times through fast Fourier transform, and obtains high harmonic content through the current extraction module. To obtain the three-phase current of the permanent magnet-assisted synchronous reluctance motor during operation, firstly perform Clark and Park transformation under the coordinates of 5th and 7th synchronous rotation, and then filter out the AC signal in the DC signal through a low-pass filter, and extract the id5th , i q5th , i d7th , i q7th signals;

The i d5th , i q5th , i d7th , i q7th signals are input to the current harmonic suppression adjustment module as the feedback link, and the current harmonic suppression adjustment module outputs the corresponding harmonic voltage components u d5th , u q5th , u d7th , u q7th , because It is expected that the 5th and 7th harmonic currents are zero, so the given i * d5th , i * q5th , i * d7th , i * q7th of the current harmonic suppression regulator are 0, and the current harmonic suppression regulator is calculated by the following formula u d5th and u q5th , u d7th and u q7th respectively formula (3), formula (4) are as follows:

where k pd5th , k pq5th , k id5th and k iq5th are the control parameters of the 5th harmonic current suppression module, respectively, and their values are adjusted based on engineering experience, where k pd7th , k pq5th , k id7th , and k iq7th are respectively 7 The control parameters of the sub-harmonic current suppression module are adjusted based on engineering experience;

u d5th , u q5th and u d7th , u q7th are respectively superimposed to generate u a5-7th , u b5-7th , u c5-7th after performing inverse Clark transformation and inverse Park transformation through the voltage transformation module;

The input of the pulse modulation module is u a *, u b * and u c *, u a *, u b * and u c * are the outputs of ud and u q after inverse Park and inverse Clark transformation, u a , u b , uc is generated by superimposing the output u a5-7th, u b5-7th, u c5-7th of the harmonic current suppression module; the output of the pulse modulation module is the conduction time T a , T b of the three-phase inverter bridge IGBT and T c , the IGBT is turned on to drive the motor to run.
The method for controlling a permanent magnet-assisted synchronous reluctance motor according to claim 1, wherein the MTPA table in the MTPA table look-up module is implemented by a calibration method, which includes, for each current amplitude is, setting The interval of i s is [0, i max ], i max is the maximum phase current of the motor, the interval of the current vector angle β is [90°, 180°], the step size of is s is set to 0.25 times i max , The step size of the current vector angle β is set to 1°, and i * d and i * q are calculated according to equation (5) for each is s :

The host computer gives different d and q axis currents i * d and i * q , and adjusts the PI parameters of the first closed-loop PI regulator and the second closed-loop PI regulator respectively. When the d and q axis currents achieve good follow-up, record T e and the output values ud and u q of the voltage calculation module; find the different combinations under each is s
The maximum torque T emax corresponding to the torque, and then the maximum torque-current ratio curve is fitted by the T emax value corresponding to each is to construct T emax respectively with
The one-dimensional table of the MTPA module is written in the program in the form of a one-dimensional array, which is used as a table lookup basis for the MTPA module.
The method for controlling a permanent magnet assisted synchronous reluctance motor according to claim 1, wherein the method for collecting the temperature T of the permanent magnet assisted synchronous reluctance motor stator is: first, in a drag test environment, make the permanent magnet assisted synchronous reluctance motor The synchronous reluctance motor runs at the rated speed, loads the motor under test, and the temperature sensor tests the temperature of the motor winding or iron core as the inductance ambient temperature. In the [-20℃, 160℃] interval, the motor is tested every 10℃. When the motor temperature value is stable, the temperature recorded at this moment is the temperature T of the stator of the permanent magnet assisted synchronous reluctance motor. A total of nineteen test temperature points are obtained in the [-20℃, 160℃] interval.
The control method of a permanent magnet-assisted synchronous reluctance motor according to claim 3, wherein the orthogonal axis flux linkage table can be obtained through a bench experiment, and the method for obtaining the table in the bench experiment is as follows: at each test temperature point, Different d -axis current id and q-axis current i q are given by the host computer to adjust the PI parameters of the first closed-loop PI regulator and the second closed-loop PI regulator respectively. When the d -axis current id and q-axis current i q After achieving good follow-up, record Te and the output values ud and u q of the voltage calculation module, and then calculate R s , ψ d , ψ q by formula (6), and formula (6) is specifically:

Record the parameters obtained from the test, and draw the two-dimensional tables of ψ d and ψ q about the d -axis current id and q-axis current i q , respectively. For each test temperature point, there is a two-dimensional table of ψ d and one of ψ q . Two-dimensional table; write several two-dimensional tables of ψ d and ψ q in the program in the form of two-dimensional arrays for table look-up.
The method for controlling a permanent magnet-assisted synchronous reluctance motor according to claim 4, wherein the method of looking up the table of the orthogonal axis flux linkage parameters is as follows; the temperature sensor collects the temperature T of the stator in real time, and each real-time temperature T Corresponding to two table look-up temperatures T s and T s+10 , T s and T s+10 are two adjacent test temperature points within the interval of [-20°C, 160°C], T is in [T s , T s+10 ] a value in the interval, the relationship between T s+10 and T s is: T S+10 =T S +10, where T s is an integer multiple of 10, and the value range of T s is [-20 °C, 160 °C]; for each table lookup temperature T s , there is a two-dimensional table of ψ d about i q , id and a two-dimensional table of ψ q about i q , id ; where i q , i The table lookup interval of d is set to be 0.05 times of the maximum current; at each table lookup temperature T s , the real-time values of ψ d and ψ q are respectively based on i * d and i * q output by the MTPA lookup table module at this moment. The two-dimensional table of ψ d and ψ q parameters is obtained by two-dimensional linear interpolation; the two parameters ψ d ( id , i q , T s ) of the d-axis flux linkage are obtained under the table temperature T s and T s+10 respectively. , ψ d ( id , i q , T s+10 ), and the two parameters of the q-axis flux linkage ψ q ( id , i q , T s ), ψ q ( id , i q , T s+ 10 ), then ψ d ( id , i q , T s ) and ψ d ( id , i q , T s+10 ), ψ q ( id , i q , T s ) and ψ q (id ) , i q , T s+10 ) according to the temperature T collected in real time, perform one-dimensional linear interpolation with respect to the temperatures T s and T s+10 , respectively, to obtain the direct-axis flux linkage value ψ d ( id , i q , T) and the intersection Axial flux linkage value ψ q ( id , i q , T).
The control method for a permanent magnet-assisted synchronous reluctance motor according to claim 5, wherein, in the calculation of the quadrature axis flux linkage look-up table module, ψ d , ψ q and motor parameters L d , L q , ψ f exist The following relationship, specifically formula (7):
The method for controlling a permanent magnet assisted synchronous reluctance motor according to claim 1, wherein the harmonic orders that can be suppressed by the harmonic current suppression module are expanded to 5th, 7th, 11th and 13th.
The method for controlling a permanent magnet assisted synchronous reluctance motor according to claim 1, wherein when calculating the harmonic voltage components u d5th and u q5th , the current harmonic suppression adjustment module firstly adjusts k pd5th and k pq5th , and then adjusts the Adjust k id5th , k iq5th , the initial values of k pd5th and k pq5th are set to 1.0, and the initial values of k id5th and k iq5th are set to 10; the current harmonic suppression adjustment module is calculating the harmonic voltage components u d7th , u q7th When , first adjust k pd7th and k pq7th , and then adjust k id7th and k iq7th . The initial values of k pd5th and k pq7th are set to 1.0, and the initial values of k id7th and k iq7th are set to 10.
The control method for a permanent magnet assisted synchronous reluctance motor according to claim 1, wherein, in the processing process of the voltage conversion module, the angle used by the inverse Park transformation of the 5th harmonic voltage component is -5θ, and the 7th harmonic voltage is The angle used by the component inverse Park transform is 7θ.
The control method of a permanent magnet assisted synchronous reluctance motor according to claim 1, wherein the pulse modulation module adopts a variety of mode modulation strategies, specifically, when the motor frequency is in [0～30Hz), asynchronous modulation is adopted, and the motor When the frequency is in [30~62Hz), synchronous modulation is adopted, when the motor frequency is in [62 ~ 90Hz), the middle 60 degree modulation is adopted, and when the motor frequency is in [90Hz ~ 200Hz], square wave control is adopted.