阅读说明：本技术 一种永磁电机定子磁链检测方法、转矩检测方法及其装置 (Permanent magnet motor stator flux linkage detection method, torque detection method and device ) 是由 杨大成 梅文庆 周志宇 丁晓帆 于 2020-05-26 设计创作，主要内容包括：本发明提供了一种永磁电机定子磁链的检测方法,具体包括：基于电压磁链模型确定上一采样时刻的第一定子磁链；基于电流磁链模型确定上一采样时刻的第二定子磁链；基于上述第一定子磁链和上述第二定子磁链确定补偿值；以及至少以上述补偿值为上述电压磁链模型的输入确定当前时刻的定子磁链。本发明还提供了基于上述定子磁链检测方法的转矩检测方法。根据本发明所提供的永磁电机定子磁链检测方法及转矩检测方法,能够在全速度范围内提高永磁电机定子磁链的计算精度,从而实现了转矩的精确控制。(The invention provides a method for detecting a permanent magnet motor stator flux linkage, which specifically comprises the following steps: determining a first stator flux linkage at the last sampling moment based on the voltage flux linkage model; determining a second stator flux linkage at the last sampling moment based on the current flux linkage model; determining a compensation value based on the first stator flux linkage and the second stator flux linkage; and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the voltage flux linkage model. The invention also provides a torque detection method based on the stator flux linkage detection method. According to the permanent magnet motor stator flux linkage detection method and the torque detection method provided by the invention, the calculation precision of the permanent magnet motor stator flux linkage can be improved in the full speed range, so that the accurate control of the torque is realized.)

1. A method for detecting a permanent magnet motor stator flux linkage is characterized by comprising the following steps:

determining a first stator flux linkage at the last sampling moment based on the voltage flux linkage model;

determining a second stator flux linkage at the last sampling moment based on the current flux linkage model;

determining a compensation value based on the first stator flux linkage and the second stator flux linkage; and

and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the voltage flux linkage model.

2. The detection method of claim 1, wherein determining the compensation value further comprises:

determining the compensation value as a flux linkage offset value between the first stator flux linkage and the second stator flux linkage.

3. The detection method of claim 1, further comprising:

determining a compensation coefficient at the current moment according to the current rotating speed of the permanent magnet motor;

determining the compensation value further comprises:

and correcting the compensation value by taking the compensation coefficient as weight.

4. The detection method of claim 3, wherein k is a function of_ω＝1-abs(ω)/ω_MAXDetermining the compensation factor, wherein

k_ωFor the compensation factor abs (ω) is the absolute value of the current speed of rotation, ω_MAXIs the maximum rotational speed of the permanent magnet motor.

5. The detection method of claim 1, wherein the voltage flux linkage model comprises an initial model and a non-initial model;

in response to the current time being an initial time, the detection method further includes:

and determining the stator flux linkage at the current moment as an initial stator flux linkage based on the initial model.

6. The detection method of claim 5, wherein in response to the last sampling time being an initial time, determining the first stator flux linkage further comprises:

determining the first stator flux linkage as the initial stator flux linkage;

determining the stator flux linkage at the current time further comprises:

and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the non-initial model.

7. The detection method of claim 5, wherein the initial model is:

and

wherein

ψ_sα(0) For the alpha axis to initiate the stator flux linkage, psi_sβ(0) The stator flux linkage is initiated for the beta axis,is a rotor permanent magnet of the permanent magnet motorAnd magnetic flux, theta, is the rotor magnetic field position at the initial moment.

8. The detection method of claim 5, wherein in response to neither the current time nor the last sampling time being an initial time, determining the first stator flux linkage further comprises:

determining a first stator flux linkage at a last sampling moment based on the non-initial model;

determining the stator flux linkage at the current time further comprises:

and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the non-initial model.

9. The detection method of claim 5, wherein the non-initial model is:

ψ_sα＝∫(u_sα-R_si_sα+Δψ_sα) (ii) a And

ψ_sβ＝∫(u_sβ-R_si_sβ+Δψ_sβ) (ii) a Wherein

ψ_sαIs an alpha-axis first stator flux linkage, psi_sβIs a beta-axis first stator flux linkage, u_sαIs the stator voltage of the alpha axis u_sβIs the stator voltage of the beta axis i_sαIs an alpha-axis stator current, i_sβIs a stator current of beta axis, R_sAs stator resistance,. DELTA.. psi_sαFor compensation of the alpha axis, Δ ψ_sβIs a beta axis offset value.

10. The detection method of claim 1, wherein determining the second stator flux linkage further comprises:

obtaining alpha axis stator current i_sαAnd beta axis stator current i_sβ；

Converting the alpha-axis stator current i according to the rotor magnetic field position theta_sαAnd beta axis stator current i_sβConverted into weak magnetic current i_dAnd torque current i_q；

With said field weakening current i_dAnd rotatingMoment current i_qDetermining a d-axis flux linkage psi for the input of the current flux linkage model_dAnd q-axis flux linkage psi_q(ii) a And

the d-axis magnetic linkage psi is determined according to the rotor magnetic field position theta_dAnd q-axis flux linkage psi_qSecond stator flux linkage converted into alpha axisAnd a beta axis second stator flux linkage

11. The detection method of claim 10, wherein the current flux linkage model is:

and

ψ_q＝L_qi_q(ii) a Wherein

Is the rotor permanent magnet flux, L, of the permanent magnet motor_dIs a direct axis inductor, L_qIs a quadrature axis inductor.

12. The detection method according to claim 10, wherein the α -axis stator current i is converted according to a rotor magnetic field position θ_sαAnd beta axis stator current i_sβConverted into weak magnetic current i_dAnd torque current i_qFurther comprising:

i_d＝cosθ*i_sα+sinθ*i_sβ(ii) a And

i_q＝-sinθ*i_sα+cosθ*i_sβ；

converting the d-axis flux linkage and the q-axis flux linkage into an alpha-axis second stator flux linkage according to the rotor magnetic field position thetaAnd a beta axis second stator flux linkageFurther comprising:

and

13. a torque detection method of a permanent magnet motor is characterized by comprising the following steps:

the method for detecting the stator flux linkage of the permanent magnet motor according to any one of claims 1-12, wherein the stator flux linkage at the current moment is determined; and

calculating a torque of the permanent magnet motor based on the stator flux linkage.

14. A torque detection device for a permanent magnet motor, comprising: a memory; and

a processor coupled to the memory, the processor configured to implement the method of torque detection for a permanent magnet motor of claim 13.

15. A detection device for permanent magnet motor stator flux linkage is characterized by comprising: a memory; and

a processor coupled to the memory, the processor configured to implement the method of detecting permanent magnet motor stator flux linkage of any of claims 1-12.

16. A computer readable medium having stored thereon computer readable instructions which, when executed by a processor, carry out the steps of the method of detecting permanent magnet motor stator flux linkage according to any of claims 1-12.

Technical Field

The invention relates to the field of control of permanent magnet motors, in particular to stator flux linkage detection and torque control based on the stator flux linkage of a permanent magnet motor.

Background

The permanent magnet motor control system has the main function of converting electric energy into mechanical energy by taking a magnetic field as a medium through controlling the permanent magnet motor in real time to drive equipment to operate. The torque control of the permanent magnet motor is the core of a permanent magnet motor control system, and the accuracy of the torque control is the most core index of the torque control. The torque of a permanent magnet motor is generally calculated by two methods, namely a rotor side torque calculation method and a stator side torque calculation method.

The calculation formula of the rotor-side torque calculation method is as follows:

in the above formula, T_eIs an electromagnetic torque, P_nThe number of the pole pairs of the motor is,is the rotor permanent magnet flux of a permanent magnet motor, L_dIs a direct axis inductor, L_qIs a quadrature axis inductor, i_dFor weak magnetic current, i_qIs the torque current.

From the above formula, it can be seen that the rotor side torque calculation method depends on the direct axis inductance L_dQuadrature axis inductor L_qAnd a weak magnetic current i_dTorque current i_q. Shaft inductance L of permanent magnet motor_dQuadrature axis inductor L_qCan change along with the saturation of magnetic flux, and the weak magnetic current i_dTorque current i_qThe calculation of (b) depends on the rotor angle, and the rotor angle measurement tends to have disturbances and fluctuations. Application experience shows that all parameters in the rotor side torque calculation method at medium and low speeds are accurate, the precision is high, and the application requirements can be met. However, the error of each parameter is large at high speed, and the final torque error can reach 20%, which is far from meeting the application requirement. The general solution is to perform motor combination tests on i in the full speed range_d，i_qVarious combinations of accurately measuring torque T by torquemeters_eForm i_d，i_q-T_eTable, in anticipation of the torque being able to meet accuracy requirements over the full speed range. However, the method needs to perform a long-time calibration test on each motor, and consumes a lot of manpower and material resources.

The calculation formula of the stator-side torque calculation method is as follows:

T_e＝1.5*P_n*(ψ_sαi_sβ-ψ_sβi_sα)； (2)

in the above formula, i_sαIs stator current i_sAlpha-axis current component in stationary coordinate system, i_sβIs stator current i_sBeta-axis current component, psi, in a stationary coordinate system_sαIs alpha-axis flux linkage psi under a static coordinate system_sβIs a beta axis magnetic linkage under a static coordinate system.

The formula can know that the stator side torque calculation method depends on stator flux linkage, and the calculation of the stator flux linkage can be based on a voltage flux linkage model, namely only depends on stator resistance parameters except stator voltage and stator current, so that the calculation is simple and has high applicability. Although the calculation of the stator side torque is simple, the application experience shows that the calculation of the stator flux linkage has deviation due to large errors in voltage measurement of the permanent magnet motor at low speed, and the calculation accuracy of the stator side torque at low speed is low. However, the stator flux linkage calculated based on the voltage flux linkage model and the stator-side torque calculated based on the stator flux linkage have high accuracy in a high-speed state, and can meet application requirements.

Based on this, a stator flux linkage detection method suitable for a permanent magnet motor is needed, which can solve the problem that a voltage flux linkage model has low calculation accuracy at a low speed, so that a torque detection method of the permanent magnet motor is provided, and the possibility is provided for realizing accurate control of the permanent magnet motor by obtaining a high-accuracy torque amount in real time.

Disclosure of Invention

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In order to solve the above problem, the present invention provides a method for detecting a stator flux linkage of a permanent magnet motor, which specifically includes:

determining a first stator flux linkage at the last sampling moment based on the voltage flux linkage model;

determining a second stator flux linkage at the last sampling moment based on the current flux linkage model;

determining a compensation value based on the first stator flux linkage and the second stator flux linkage; and

and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the voltage flux linkage model.

In an embodiment of the detection method, optionally, the determining the compensation value further includes:

and determining the compensation value as a flux linkage deviation value between the first stator flux linkage and the second stator flux linkage.

In an embodiment of the foregoing detection method, optionally, the detection method further includes:

determining a compensation coefficient at the current moment according to the current rotating speed of the permanent magnet motor;

determining the compensation value further comprises:

and correcting the compensation value by taking the compensation coefficient as a weight.

In an embodiment of the above detection method, optionally, according to k_ω＝1-abs(ω)/ω_MAXDetermining the above compensation coefficient, wherein

k_ωFor the compensation factor, abs (ω) is the absolute value of the current speed, ω_MAXThe maximum rotational speed of the permanent magnet motor.

In an embodiment of the detection method, optionally, the voltage flux linkage model includes an initial model and a non-initial model;

in response to the current time being an initial time, the detecting method further includes:

determining the stator flux linkage at the current moment as an initial stator flux linkage based on the initial model;

determining the stator flux linkage at the current time further comprises:

and determining the stator flux linkage at the current moment by using at least the compensation value as the input of the non-initial model.

In an embodiment of the detection method, optionally, in response to that the last sampling time is an initial time, determining the first stator flux linkage further includes:

and determining the first stator flux linkage as the initial stator flux linkage.

In an embodiment of the detection method, optionally, the initial model is:

and

wherein

ψ_sα(0) For the alpha axis to initiate the stator flux linkage, psi_sβ(0) The stator flux linkage is initiated for the beta axis,θ is the rotor permanent magnet flux of the permanent magnet motor, and θ is the rotor magnetic field position at the initial time.

In an embodiment of the detection method, optionally, in response to that neither the current time nor the last sampling time is an initial time, determining the first stator flux linkage further includes:

determining a first stator flux linkage at the last sampling moment based on the non-initial model;

determining the stator flux linkage at the current time further comprises:

and determining the stator flux linkage at the current moment by using at least the compensation value as the input of the non-initial model.

In an embodiment of the detection method, optionally, the non-initial model is:

ψ_sα＝∫(u_sα-R_si_sα+Δψ_sα) (ii) a And

ψ_sβ＝∫(u_sβ-R_si_sβ+Δψ_sβ) (ii) a Wherein

ψ_sαIs an alpha-axis first stator flux linkage, psi_sβIs a beta-axis first stator flux linkage, u_sαIs the stator voltage of the alpha axis u_sβIs the stator voltage of the beta axis i_sαIs an alpha-axis stator current, i_sβIs a stator current of beta axis, R_sAs stator resistance,. DELTA.. psi_sαFor compensation of the alpha axis, Δ ψ_sβIs a beta axis offset value.

In an embodiment of the detection method, optionally, the determining the second stator flux linkage further includes:

obtaining alpha axis stator current i_sαAnd beta axis stator current i_sβ；

According to the rotor magnetic field position theta, the alpha-axis stator current i is converted_sαAnd beta axis stator current i_sβConverted into weak magnetic current i_dAnd torque current i_q；

With the above-mentioned weak magnetic current i_dAnd torque current i_qDetermining d-axis flux linkage psi for input to the current flux linkage model_dAnd q-axis flux linkage psi_q(ii) a And

the d-axis flux linkage psi is generated according to the rotor magnetic field position theta_dAnd q-axis flux linkage psi_qSecond stator flux linkage converted into alpha axisAnd a beta axis second stator flux linkage

In an embodiment of the detection method, optionally, the current flux linkage model is:

and

ψ_q＝L_qi_q(ii) a Wherein

Is the rotor permanent magnet flux, L, of the permanent magnet motor_dIs a direct axis inductor, L_qIs a quadrature axis inductor.

In an embodiment of the above detection method, optionally, the α -axis stator current i is adjusted according to the rotor magnetic field position θ_sαAnd beta axis stator current i_sβConverted into weak magnetic current i_dAnd torque current i_qFurther comprising:

i_d＝cosθ*i_sα+sinθ*i_sβ(ii) a And

i_q＝-sinθ*i_sα+cosθ*i_sβ；

converting the d-axis flux linkage and the q-axis flux linkage into an alpha-axis second stator flux linkage according to the rotor magnetic field position thetaAnd a beta axis second stator flux linkageFurther comprising:

and

the invention also provides a torque detection method of the permanent magnet motor, which specifically comprises the following steps:

determining the stator flux linkage at the current moment according to any one embodiment of the detection method of the stator flux linkage of the permanent magnet motor; and

and calculating the torque of the permanent magnet motor based on the stator flux linkage.

The invention also provides a torque detection device of the permanent magnet motor, which specifically comprises: a memory; and

and a processor coupled with the memory, the processor being configured to implement the torque detection method of the permanent magnet motor as described above.

The invention also provides a device for detecting the permanent magnet motor stator flux linkage, which specifically comprises: a memory; and

and a processor coupled with the memory, wherein the processor is configured to implement any one of the embodiments of the method for detecting the stator flux linkage of the permanent magnet motor.

The invention also provides a computer readable medium on which computer readable instructions are stored, which when executed by a processor implement any one of the embodiments of the method for detecting stator flux linkage of a permanent magnet motor as described above.

According to the permanent magnet motor stator flux linkage detection method provided by the invention, the stator flux linkage of the permanent magnet motor is calculated based on the current flux linkage model and the voltage flux linkage model simultaneously, so that the compensation value can be determined based on the stator flux linkage calculated by the two models, the stator flux linkage obtained based on the voltage flux linkage model can be compensated in a closed loop manner, the detection precision of the permanent magnet motor stator flux linkage can be improved in the full speed range, the torque precision obtained based on the stator flux linkage can be effectively improved, and the control of the permanent magnet motor can be realized more accurately. The invention also provides a torque detection method of the permanent magnet motor, and based on the detection method of the stator flux linkage provided by the invention, the torque detection method provided by the invention can effectively realize accurate detection of the torque, thereby more accurately realizing the control of the permanent magnet motor.

Drawings

The above features and advantages of the present disclosure will be better understood upon reading the detailed description of embodiments of the disclosure in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale, and components having similar relative characteristics or features may have the same or similar reference numerals.

Fig. 1 is a schematic flow chart illustrating an embodiment of a method for detecting a stator flux linkage of a permanent magnet motor according to an aspect of the present invention.

Fig. 2 shows a model block diagram of an embodiment of a permanent magnet motor stator flux linkage detection method according to an aspect of the present invention.

Fig. 3 is a schematic flow chart illustrating an embodiment of a method for detecting a stator flux linkage of a permanent magnet motor according to an aspect of the present invention

Fig. 4 shows a schematic structural diagram of a permanent magnet motor stator flux linkage detection device provided by another aspect of the present invention.

Fig. 5 shows a schematic structural diagram of a permanent magnet motor torque detection device provided by another aspect of the invention.

Reference numerals

400 stator flux linkage detection device

410 processor

420 memory

500 torque detection device

510 processor

520 memory

Detailed Description

The following description is presented to enable any person skilled in the art to make and use the invention and is incorporated in the context of a particular application. Various modifications, as well as various uses in different applications will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to a wide range of embodiments. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the practice of the invention may not necessarily be limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All the features disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Note that where used, the designations left, right, front, back, top, bottom, positive, negative, clockwise, and counterclockwise are used for convenience only and do not imply any particular fixed orientation. In fact, they are used to reflect the relative position and/or orientation between the various parts of the object. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

It is noted that, where used, further, preferably, still further and more preferably is a brief introduction to the exposition of the alternative embodiment on the basis of the preceding embodiment, the contents of the further, preferably, still further or more preferably back band being combined with the preceding embodiment as a complete constituent of the alternative embodiment. Several further, preferred, still further or more preferred arrangements of the belt after the same embodiment may be combined in any combination to form a further embodiment.

The invention is described in detail below with reference to the figures and specific embodiments. It is noted that the aspects described below in connection with the figures and the specific embodiments are only exemplary and should not be construed as imposing any limitation on the scope of the present invention.

As described above, accurate control of the torque of the permanent magnet motor can be achieved by obtaining accurate stator end flux linkage. The method is a basic method for observing the stator flux linkage through a voltage flux linkage model in an alternating-current speed regulation system, and the voltage flux linkage model has the advantages of simple algorithm, small dependence on motor parameters and the like (only stator resistance parameters are needed), so that the voltage model flux linkage observation method is always valued by people.

A common voltage flux linkage model is as follows:

ψ_s＝∫(u_s-R_si_s)dt

the digitized form of the voltage flux linkage model of the permanent magnet motor stator flux linkage under the static coordinate system is as follows:

ψ_s(N)＝ψ_s(N-1)+(u_s-R_si_s)*dt

in the voltage flux linkage model method, the precision of the acquired voltage flux linkage depends on the sampling voltage u_sAnd stator resistance R_s. As mentioned above, the model is simple and reliable, although at low speed of the permanent magnet motor the voltage u is sampled_sThe large occupancy ratio results in low magnetic flux linkage calculation accuracy, but the magnetic flux linkage calculation accuracy is high at medium and high speeds.

In order to solve the problem of low precision of the stator end flux linkage at low speed, the present invention provides a stator flux linkage detection method, and referring to fig. 1, fig. 1 shows a schematic flow diagram of an embodiment of a permanent magnet motor stator flux linkage detection method provided in an aspect of the present invention.

As shown in fig. 1, the stator flux linkage detection method provided by the present invention includes step S110: determining a first stator flux linkage at the last sampling moment based on the voltage flux linkage model; step S120: determining a second stator flux linkage at the last sampling moment based on the current flux linkage model; step S130: determining a compensation value based on the first stator flux linkage and the second stator flux linkage; and step S140: and determining the stator flux linkage at the current moment by taking at least the compensation value as the input of the voltage flux linkage model.

The above steps S110 to S140 can be understood by referring to the model block diagram of the flux linkage detection method shown in fig. 2. In the model block diagram as shown in fig. 2, the following definitions are provided:

u_s(u_sα，u_sβ) Is the stator voltage u_sαIs u_sVoltage component of alpha axis, u, in a stationary coordinate system_sβIs u_sA beta axis voltage component in a stationary coordinate system;

i_s(i_sα，i_sβ) Is a statorCurrent, i_sαIs i_sAlpha-axis current component, i, in a stationary coordinate system_sβIs i_sA beta axis current component in a stationary coordinate system;

ψ_sαalpha-axis stator flux linkage psi in a stationary coordinate system calculated for a voltage flux linkage model_sβCalculating a beta-axis stator flux linkage under a static coordinate system for the voltage flux linkage type;

alpha-axis stator flux linkage in a stationary coordinate system calculated for the current flux linkage model,calculating a beta-axis stator flux linkage under a static coordinate system for the current model;

Δψ_sαfor stator flux linkage deviation of the alpha axis, Delta psi_sβIs the beta axis stator flux linkage deviation;

ψ_dfor d-axis flux linkage, psi, under orientation of rotor field_qA q-axis flux linkage oriented for the rotor field;

i_dfor weak magnetic current, i_qIn order to be the torque current,is the permanent magnet flux of the permanent magnet motor rotor, L_dIs a direct axis inductor, L_qIs a quadrature axis inductor, R_sIs stator resistance, theta is rotor field position, coefficient k_ωAre error compensation coefficients.

In the above model, 1, the stator current i is first collected by the sensor_sAnd the rotor magnetic field position theta is obtained, and the given voltage u of the motor stator is obtained_s；

2. I is converted according to the theta position by a current coordinate conversion unit_sIs converted into i_d，i_q；

3. Find psi_d，ψ_q；

4. By means of a coordinate transformation unit, according to the theta position_d，ψ_qIs converted into

5. Calculating the deviation delta psi_sα，Δψ_sβAnd obtaining the current rotating speed of the permanent magnet motor to obtain the correction delta psi_sα，Δψ_sβThe error compensation coefficient of (1);

6. will i_s，u_sAnd corrected Δ ψ_sα，Δψ_sβSubstituting the voltage flux linkage model to calculate psi_sα，ψ_sβ。

The stator flux linkage detection method provided by the invention can be considered as compensating the voltage flux linkage model through the current flux linkage model on the basis of the voltage flux linkage model. That is, the stator flux linkage is obtained based on a voltage flux linkage model with a compensation amount. The voltage flux linkage model provided by the invention has compensation quantity, so that the obtained stator flux linkage is corrected, and the corrected stator flux linkage is ensured to always keep higher precision in the low-speed running state of the motor.

In the present invention, the voltage flux linkage model further includes an initial model and a non-initial model. And in response to the current moment being the initial moment, initializing by using an initial model to obtain an initial stator flux linkage. And in response to any time after the initial time at the present time, adopting a non-initial model, namely a voltage flux linkage model with a compensation quantity, to obtain the corrected stator flux linkage.

For the initial model, please refer to fig. 3, in the initial state, the initial stator flux linkage needs to be obtained through the initial model first. Specifically, in the initial state, the rotor magnetic field position θ is read as an input of the initial model to_sα，ψ_sβInitialization is performed. The initial model specifically comprises:

and

wherein

ψ_sα(0) For the alpha axis to initiate the stator flux linkage, psi_sβ(0) The stator flux linkage is initiated for the beta axis,is the rotor permanent magnet flux of a permanent magnet motor.

The non-initial model in the voltage flux linkage model gives a voltage u with the stator at the current moment_sStator current i_sThe compensation quantity delta phi determined at the last sampling instant_sα，Δψ_sβThe corrected stator flux linkage at the current time is obtained as an input. The non-initial model is specifically as follows:

ψ_sα＝∫(u_sα-R_si_sα+Δψ_sα) (ii) a And

ψ_sβ＝∫(u_sβ-R_si_sβ+Δψ_sβ) (ii) a Wherein

ψ_sαIs an alpha-axis first stator flux linkage, psi_sβIs a beta-axis first stator flux linkage, u_sαIs the stator voltage of the alpha axis u_sβIs the stator voltage of the beta axis i_sαIs an alpha-axis stator current, i_sβIs a stator current of beta axis, R_sAs stator resistance,. DELTA.. psi_sαFor compensation of the alpha axis, Δ ψ_sβIs a beta axis offset value.

Please refer to fig. 2 to understand the non-initial model of the voltage flux linkage model. Specifically, fig. 2 shows a preferred embodiment of the non-initial model, that is, in the non-initial model shown in fig. 2, the compensation value is further modified.

As can be seen from fig. 2, a preferred embodiment of the non-initial model of the voltage flux linkage model provided by an aspect of the present invention is:

ψ_sα＝∫(u_sα-R_si_sα+k_ω*Δψ_sα) (ii) a And

ψ_sβ＝∫(u_sβ-R_si_sβ+k_ω*Δψ_sβ) (ii) a Wherein

k_ωFor supplementingBy compensating for the coefficient k_ωCorrecting the compensation amount delta phi for the weight_sα，Δψ_sβThe error of the stator flux linkage can be further reduced.

Specifically, in one embodiment, the compensation factor k_ωIs determined based on the current rotational speed of the permanent magnet motor. That is to say the compensation factor k_ωAnd dynamically taking values along with the change of the rotating speed. Compensation factor k_ωThe value is larger when the permanent magnet motor is in a low-speed state so as to increase torque error compensation; and when the permanent magnet motor is in a medium-high speed state, the value is small so as to reduce the torque error compensation.

More preferably, another aspect of the present invention further provides the above compensation coefficient k_ωA setting method of (1), namely:

k_ω＝1-abs(ω)/ω_MAXwherein

abs (omega) is the absolute value of the current speed of rotation, omega_MAXThe maximum rotation speed of the permanent magnet motor is obtained in advance.

According to the compensation coefficient k_ωWhen ω is 0, k is set to_ω1 is ═ 1; when ω is ω ═ ω_MAXWhen k is_ω＝0。

Since one of the inputs of the non-initial model of the voltage flux linkage model provided by the aspect of the present invention is the compensation amount determined at the last sampling time, the aspect of the present invention further includes determining the compensation amount at the last sampling time. Specifically, in the invention, the compensation value is determined according to the first stator flux linkage determined based on the voltage flux linkage model at the last sampling moment and the second stator flux linkage determined based on the current flux linkage model.

As for step S110 in fig. 1, as described above, when the previous sampling time is the initial time, the first stator flux linkage at the previous sampling time is determined through the initial model of the voltage flux linkage model, and if the previous sampling time is not the initial time, the first stator flux linkage at the previous sampling time is iteratively determined through the non-initial model of the voltage flux linkage model.

For step S120 in fig. 1, please refer to the model block diagram in fig. 2 to understand the calculation based on the current flux linkage modelSecond stator flux linkage at last sampling momentAndas shown in fig. 2, the calculating the stator flux linkage according to the current flux linkage model specifically includes:

1. collecting stator current i at last sampling moment through sensor_sAnd rotor field position θ.

2. Stator current i_sAnd the rotor magnetic field position theta is used as the input of current coordinate conversion to obtain weak magnetic current i_dAnd torque current i_qWherein

i_d＝cosθ*i_sα+sinθ*i_sβ；

i_q＝-sinθ*i_sα+cosθ*i_sβ。

3. Will weaken magnetic current i_dTorque current i_qRotor permanent magnet flux of permanent magnet motorStraight axis inductance L_dAnd quadrature axis inductance L_qObtaining d-axis flux linkage psi under rotor magnetic field orientation as input of current flux linkage model_dQ-axis flux linkage psi with rotor field orientation_q(ii) a Wherein the current flux linkage model is specifically

And

ψ_q＝L_qi_q。

4. d-axis flux linkage psi for orienting rotor magnetic field_dQ-axis flux linkage psi with rotor field orientation_qObtaining a second stator flux linkage obtained through a current flux linkage model as an input of coordinate transformationAndwherein

And

first stator flux linkage psi when the last sampling instant has been determined by the voltage flux linkage model_sαAnd psi_sβDetermining the second stator flux linkage of the last sampling moment through the current flux linkage modelAndafter that, step S130 is executed: a compensation value is determined based on the first stator flux linkage and the second stator flux linkage.

In an embodiment, the compensation value is determined as the first stator flux linkage ψ_sα、ψ_sβAnd a second stator flux linkage The flux linkage deviation value therebetween, i.e.

And

the compensation value delta phi at the moment when the last sample has been determined_sα、Δψ_sβThen, at least by the offset value Δ ψ_sα、Δψ_sβAnd determining the stator flux linkage at the current sampling moment for the input of the non-initial model in the voltage flux linkage model, wherein the stator flux linkage is corrected, the error is small, and the precision is high. As mentioned above, in a preferred embodiment, the offset Δ ψ may be corrected_sα、Δψ_sβCorrection is performed to further reduce the error.

Specifically, after digitizing a preferred embodiment of the non-initial model in the voltage flux linkage model, the following model can be obtained:

ψ_sα(N)＝ψ_sα(N-1)+(u_sα-R_si_sα+k_ω*Δψ_sα) Dt; and

ψ_sβ(N)＝ψ_sβ(N-1)+(u_sβ-R_si_sβ+k_ω*Δψ_sβ)*dt。

according to the permanent magnet motor stator flux linkage detection method provided by the invention, the stator flux linkage of the permanent magnet motor is calculated based on the current flux linkage model and the voltage flux linkage model simultaneously, so that the compensation value can be determined based on the stator flux linkage calculated by the two models, the stator flux linkage obtained based on the voltage flux linkage model can be compensated in a closed loop manner, the detection precision of the permanent magnet motor stator flux linkage can be improved in the full speed range, the torque precision obtained based on the stator flux linkage can be effectively improved, and the control of the permanent magnet motor can be realized more accurately.

The invention further provides a device for detecting the stator flux linkage of the permanent magnet motor, please refer to fig. 4, and fig. 4 shows a schematic diagram of the device for detecting the stator flux linkage of the permanent magnet motor. As shown in fig. 4, the stator flux linkage detection apparatus 400 includes a processor 410 and a memory 420. The processor 410 of the stator flux linkage detection apparatus 400 can implement the above described stator flux linkage detection method when executing the computer program stored in the memory 420, for which reference is specifically made to the above description of the stator flux linkage detection method, which is not described herein again.

The method and the device for detecting the stator flux linkage of the permanent magnet motor provided by the aspect of the invention have been described so far. The invention also provides a computer storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method of detecting a stator flux linkage of a permanent magnet motor as described above. Specifically, please refer to the above description of the method for detecting the stator flux linkage of the permanent magnet motor, which is not repeated herein.

The invention also provides a torque detection method of the permanent magnet motor, which is based on the detection method of the stator flux linkage. After the stator flux linkage of the permanent magnet motor is obtained through any one of the embodiments of the method for detecting the stator flux linkage of the permanent magnet motor provided by the aspect of the invention, the stator side torque of the permanent magnet motor is obtained based on the stator side torque calculation method. Namely:

T_e＝1.5*P_n*(ψ_sαi_sβ-ψ_sβi_sα) (ii) a Wherein

T_eIs stator side electromagnetic torque, P_nIs the number of pole pairs, i, of the motor_sαIs stator current i_sAlpha-axis current component in stationary coordinate system, i_sβIs stator current i_sBeta-axis current component, psi, in a stationary coordinate system_sαThe method for detecting the stator flux linkage of the permanent magnet motor determines the alpha-axis stator flux linkage psi under the static coordinate system_sβThe invention provides a method for detecting stator flux linkage of a permanent magnet motor, which is used for determining the stator flux linkage of a beta axis in a static coordinate system. According to the torque detection method provided by the invention, the accurate detection of the torque can be effectively realized, so that the control on the permanent magnet motor can be more accurately realized.

The invention further provides a torque detection device of a permanent magnet motor, please refer to fig. 5, and fig. 5 shows a schematic diagram of the torque detection device of the permanent magnet motor. As shown in fig. 5, torque detection device 500 includes a processor 510 and a memory 520. The processor 510 of the torque detection apparatus 500 can implement the above described torque detection method of the permanent magnet motor when executing the computer program stored in the memory 520, and please refer to the above description of the torque detection method of the permanent magnet motor, which is not described herein again.

The present invention provides a method and apparatus for detecting stator flux linkage of a permanent magnet motor, a method and apparatus for detecting torque of a permanent magnet motor. According to the permanent magnet motor stator flux linkage detection method provided by the invention, the stator flux linkage of the permanent magnet motor is calculated based on the current flux linkage model and the voltage flux linkage model simultaneously, so that the compensation value can be determined based on the stator flux linkage calculated by the two models, the stator flux linkage obtained based on the voltage flux linkage model can be compensated in a closed loop manner, the detection precision of the permanent magnet motor stator flux linkage can be improved in the full speed range, the torque precision obtained based on the stator flux linkage can be effectively improved, and the control of the permanent magnet motor can be realized more accurately. Based on the method for detecting the stator flux linkage provided by the invention, the method for detecting the torque provided by the invention can effectively realize accurate detection of the torque, so that the control on the permanent magnet motor can be realized more accurately.

The various illustrative logical modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk (disk) and disc (disc), as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks (disks) usually reproduce data magnetically, while discs (discs) reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. It is to be understood that the scope of the invention is to be defined by the appended claims and not by the specific constructions and components of the embodiments illustrated above. Those skilled in the art can make various changes and modifications to the embodiments within the spirit and scope of the present invention, and these changes and modifications also fall within the scope of the present invention.