阅读说明：本技术 基于准比例谐振的自适应观测器及永磁同步电机位置估算方法 (Adaptive observer based on quasi-proportional resonance and permanent magnet synchronous motor position estimation method ) 是由 安群涛 安琦 刘兴亚 张建秋 谢成龙 李帅 于 2018-06-28 设计创作，主要内容包括：本发明公开了基于准比例谐振的自适应观测器及永磁同步电机位置估算方法,涉及电机控制领域。基于准比例谐振的自适应观测器的观测单元用以根据电压、反电势估计值和电机转速估计值计算,以获取电流观测值；比较单元用以将所述电流观测值与电流检测值进行比较,获取电流差值；准比例谐振控制单元用以根据所述电流差值和所述电机转速估计值计算,以获取所述反电势估计值；锁相环用以根据所述反电势估计值获取所述电机转速估计值和电机转子角度。通过准比例谐振控制单元代替滑模观测器中的切换函数,消除了抖振问题,并省去了低通滤波器,避免了低通滤波带来的相位延迟,提高了永磁同步电机位置和速度估算的精度。(The invention discloses a quasi-proportional resonance-based adaptive observer and a permanent magnet synchronous motor position estimation method, and relates to the field of motor control. The observation unit of the adaptive observer based on the quasi-proportional resonance is used for calculating according to the voltage, the back electromotive force estimated value and the motor rotating speed estimated value so as to obtain a current observed value; the comparison unit is used for comparing the current observation value with a current detection value to obtain a current difference value; the quasi-proportional resonance control unit is used for calculating according to the current difference value and the motor rotating speed estimated value so as to obtain the counter electromotive force estimated value; and the phase-locked loop is used for acquiring the motor rotating speed estimated value and the motor rotor angle according to the back electromotive force estimated value. The quasi-proportional resonance control unit replaces a switching function in the sliding mode observer, the problem of buffeting is eliminated, a low-pass filter is omitted, phase delay caused by low-pass filtering is avoided, and the position and speed estimation accuracy of the permanent magnet synchronous motor is improved.)

1. An adaptive observer based on quasi-proportional resonance, comprising:

the observation unit is used for calculating according to the voltage, the counter electromotive force estimated value and the motor rotating speed estimated value so as to obtain a current observed value;

the comparison unit is connected with the observation unit and used for comparing the current observation value with a current detection value to obtain a current difference value;

it is characterized by also comprising:

the quasi-proportional resonance control unit is connected with the observation unit and the comparison unit and used for calculating according to the current difference value and the motor rotating speed estimated value so as to obtain the counter electromotive force estimated value;

and the phase-locked loop is respectively connected with the observation unit and the quasi-proportional resonance control unit and is used for acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

2. The quasi-proportional resonance-based adaptive observer according to claim 1, wherein the observation unit employs a current state observer.

3. The quasi-proportional resonance-based adaptive observer according to claim 2, wherein the current state observer obtains the current observation by calculating using the following formula:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;

4. The quasi-proportional resonance-based adaptive observer according to claim 1, wherein the comparison unit employs a comparator.

5. The quasi-proportional resonance-based adaptive observer according to claim 1, wherein the quasi-proportional resonance control unit employs a quasi-proportional resonance controller.

6. The quasi-proportional resonance-based adaptive observer according to claim 5, wherein the quasi-proportional resonance controller obtains the back emf estimate using a transfer function calculation, the transfer function being:

wherein k is_pIs the proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;the estimated value of the motor rotating speed is obtained; t is a sampling period; z is a discretized process variable, i.e., a Z-transform operator.

7. A permanent magnet synchronous motor position estimation method of an adaptive observer based on quasi-proportional resonance is characterized by comprising the following steps:

s1, calculating according to the voltage, the counter potential estimated value and the motor rotating speed estimated value to obtain a current observed value;

s2, comparing the current observation value with a current detection value to obtain a current difference value;

s3, calculating according to the current difference value and the motor rotating speed estimated value to obtain the back electromotive force estimated value;

and S4, acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

8. The method for estimating the position of the permanent magnet synchronous motor of the adaptive observer based on quasi-proportional resonance according to claim 7, wherein the step S1 of calculating according to the voltage, the back electromotive force estimated value and the motor rotation speed estimated value to obtain the current observed value comprises:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;is an alpha axis current observed value under an alpha beta coordinate system;

9. The method for estimating the position of the PMSM based on the adaptive observer of quasi-proportional resonance (SPR) according to claim 7, wherein the step S3 of calculating according to the current difference value and the estimated value of the motor speed to obtain the estimated value of the back electromotive force comprises:

the quasi-proportional resonance controller obtains the estimated back emf value by adopting a transfer function calculation, wherein the transfer function is as follows:

wherein k is_pIs the proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;

Technical Field

The invention relates to the field of motor control, in particular to a self-adaptive observer based on quasi-proportional resonance and a position estimation method of a permanent magnet synchronous motor.

Background

Position sensorless control techniques are widely used in low cost and high sensor environment requirements. The position estimation method of the permanent magnet synchronous motor is generally classified into a low-speed section estimation method and a medium-high speed section estimation method. The observer is a common method for estimating the position and the speed of a middle-high speed section by observing the back electromotive force or flux linkage of a motor related to the rotor angle in real time and extracting the rotor angle and speed information from the back electromotive force or flux linkage, and the methods comprise a sliding-mode observer, a Longbeige observer, an extended Kalman filter and the like. The sliding-mode observer has the advantages of simple structure, good robustness and the like, and is a more common position estimation method. However, the sliding mode surface switching function constructed by the sliding mode observer is usually a sign function, which causes a serious buffeting problem. Although the buffeting can be suppressed by using a saturation function or the like, it cannot be eliminated.

Disclosure of Invention

Aiming at the problems, the invention provides a self-adaptive observer based on quasi-proportional resonance and a position estimation method of a permanent magnet synchronous motor, which can eliminate the buffeting problem.

An adaptive observer based on quasi-proportional resonance, comprising:

the observation unit is used for calculating according to the voltage, the counter electromotive force estimated value and the motor rotating speed estimated value so as to obtain a current observed value;

the comparison unit is connected with the observation unit and used for comparing the current observation value with a current detection value to obtain a current difference value;

the invention also discloses a quasi-proportional resonance-based adaptive observer, which comprises:

the quasi-proportional resonance control unit is connected with the observation unit and the comparison unit and used for calculating according to the current difference value and the motor rotating speed estimated value so as to obtain the counter electromotive force estimated value;

and the phase-locked loop is respectively connected with the observation unit and the quasi-proportional resonance control unit and is used for acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

Preferably, the observation unit employs a current state observer.

Preferably, the current state observer calculates and obtains the current observed value by using the following formula:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;

is an alpha axis current observed value under an alpha beta coordinate system;

is a beta axis current observed value under an alpha beta coordinate system; z is a radical of_αIs the output value of the alpha axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the alpha axis

z_βIs the output value of the beta axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the beta axis

And the estimated value of the motor rotating speed is obtained.

Preferably, the comparison unit adopts a comparator.

Preferably, the quasi-proportional resonance control unit adopts a quasi-proportional resonance controller.

Preferably, the quasi-proportional resonant controller obtains the estimated back emf value by calculating a transfer function, where the transfer function is:

wherein k is_pIs the proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;

the estimated value of the motor rotating speed is obtained; t is a sampling period; z is a discretized process variable, i.e., a Z-transform operator.

The invention also provides a method for estimating the position of the permanent magnet synchronous motor of the adaptive observer based on quasi-proportional resonance, which comprises the following steps:

s1, calculating according to the voltage, the counter potential estimated value and the motor rotating speed estimated value to obtain a current observed value;

s2, comparing the current observation value with a current detection value to obtain a current difference value;

s3, calculating according to the current difference value and the motor rotating speed estimated value to obtain the back electromotive force estimated value;

and S4, acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

Preferably, the step S1 of calculating according to the voltage, the back electromotive force estimated value and the motor rotation speed estimated value to obtain a current observed value includes:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;

is an alpha axis current observed value under an alpha beta coordinate system;is a beta axis current observed value under an alpha beta coordinate system; z is a radical of_αIs the output value of the alpha axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the alpha axisz_βIs the output value of the beta axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the beta axisAnd the estimated value of the motor rotating speed is obtained.

Preferably, step S3 is performed to obtain the back electromotive force estimation value according to the current difference and the motor rotation speed estimation value, and includes:

the quasi-proportional resonance controller obtains the estimated back emf value by adopting a transfer function calculation, wherein the transfer function is as follows:

wherein k is_pIs the proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;

the estimated value of the motor rotating speed is obtained; t is a sampling period; z is a discretized process variable, i.e., a Z-transform operator.

The beneficial effects of the above technical scheme are that:

in the technical scheme, the quasi-proportional resonance control unit replaces a switching function in the sliding mode observer, so that the problem of buffeting is solved, a low-pass filter is omitted, phase delay caused by low-pass filtering is avoided, and the position and speed estimation accuracy of the permanent magnet synchronous motor is improved.

Drawings

FIG. 1 is a block diagram of a permanent magnet synchronous motor position-free control system based on a sliding-mode observer;

FIG. 2 is a block diagram of a conventional sliding mode observer;

FIG. 3 is a block diagram of the quasi-proportional resonance-based adaptive observer according to the present invention;

FIG. 4 is a block diagram of one embodiment of a quasi-proportional resonance-based adaptive observer of the present invention;

FIG. 5a is a graph of amplitude-frequency characteristics of a quasi-proportional resonant controller;

FIG. 5b is a phase-frequency characteristic diagram of the quasi-proportional resonant controller;

FIG. 6a is a current observation waveform of a conventional sliding mode observer;

FIG. 6b is a current observation waveform diagram of the adaptive observer based on quasi-proportional resonance according to the present invention;

FIG. 7a is a diagram of a back-emf observation waveform of a conventional sliding-mode observer;

FIG. 7b is a diagram of a back emf observation waveform of the quasi-proportional resonance-based adaptive observer of the present invention;

FIG. 8a is a graph of a position estimation error of a conventional sliding mode observer;

FIG. 8b is a graph of the error of position estimation of the adaptive observer based on quasi-proportional resonance according to the present invention;

FIG. 9a is a graph of the speed estimation error of a conventional sliding mode observer;

FIG. 9b is a graph of the error of velocity estimation of the adaptive observer based on quasi-proportional resonance according to the present invention;

fig. 10 is a flowchart of a method for estimating a position of a permanent magnet synchronous motor based on a quasi-proportional resonance adaptive observer according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

Fig. 1 is a block diagram of a permanent magnet synchronous motor position vector-free control system based on a sliding-mode observer. The device comprises a speed controller 1, a q-axis current controller 2, a d-axis current controller 3, Park inverse transformation 4, a space vector PWM 5, a three-phase inverter 6, a permanent magnet synchronous motor 7, a Clarke transformation 8, a Park transformation 9, a sliding mode position and speed estimation module 10 and the like. The system is a speed and current double closed-loop structure, the outer ring is a rotating speed ring, and the inner ring is a d-axis current ring and a q-axis current ring under vector decoupling. Sliding mode position and speed estimation module 10 for estimating rotor position of an electric machine in real time

And velocity

Instead of a mechanical rotor position sensor. Wherein the estimated rotor position of the electric machine

Park transformation 9 and Park inverse transformation 4 for use in vector control systems, estimated motor rotor speed

As a feedback quantity for the speed loop. The input quantity of the sliding mode position and speed estimation module 10 is a given value u of alpha and beta axis voltage_αAnd u_βAlpha beta axis currentDetection value i_αAnd i_βThe output being an estimate of rotor position

And rotor speed estimate

Fig. 2 is a block diagram of a conventional sliding mode observer for the sliding mode position and velocity estimation module 10 of fig. 1. It consists of a current state observer 11, a comparator 12, a switching function 13, a low-pass filter 14 and a phase locked loop 15.

The current state observer 11 is implemented in the following way:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;is an alpha axis current observed value under an alpha beta coordinate system;

is a beta axis current observed value under an alpha beta coordinate system; z is a radical of_αIs the output value of the alpha axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the alpha axis

z_βIs the output value of the beta axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the beta axis

And the estimated value of the motor rotating speed is obtained.

Comparator 12 compares the current observed value

And a detection value i_α、i_βAnd calculating a difference value, namely:

the switching function 13 typically takes the sign function, i.e.:

wherein k is a gain, and the value of k is larger than the maximum value of counter potential amplitude values of an alpha axis and a beta axis; sgn () is a sign function.

The low pass filter 14 typically uses a first order low pass filter to obtain the back emf estimate

Namely:

wherein, ω is_cfThe cut-off frequency of the low-pass filter.

Because the sliding mode surface switching function constructed by the sliding mode observer is a sign function, the problem of severe buffeting is caused. Although the buffeting can be suppressed by using a saturation function or the like, it cannot be eliminated.

Based on the problems, the quasi-proportional resonance control unit is adopted to replace a switching function in the sliding mode observer, so that the problem of buffeting is solved, a low-pass filter is omitted, phase delay caused by low-pass filtering is avoided, and the position and speed estimation accuracy of the permanent magnet synchronous motor is improved.

As shown in fig. 3, an adaptive observer based on quasi-proportional resonance includes:

the observation unit is used for calculating according to the voltage, the counter electromotive force estimated value and the motor rotating speed estimated value so as to obtain a current observed value;

the comparison unit is connected with the observation unit and used for comparing the current observation value with a current detection value to obtain a current difference value;

the invention also discloses a quasi-proportional resonance-based adaptive observer, which comprises:

the quasi-proportional resonance control unit is connected with the observation unit and the comparison unit and used for calculating according to the current difference value and the motor rotating speed estimated value so as to obtain the counter electromotive force estimated value;

and the phase-locked loop is respectively connected with the observation unit and the quasi-proportional resonance control unit and is used for acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

Further, the observation unit may employ a current state observer, and the comparison unit may employ a comparator; the quasi-proportional resonant control unit may employ a quasi-proportional resonant controller.

Fig. 4 is a block diagram of an embodiment of the adaptive observer based on quasi-proportional resonance of the present invention, in which the switching function 13 and the low-pass filter 14 are replaced by a quasi-proportional resonance controller 16 on the basis of the conventional sliding mode observer shown in fig. 2.

In this embodiment, the current state observer calculates and obtains the current observed value by using the following formula:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;

is an alpha axis current observed value under an alpha beta coordinate system;

is a beta axis current observed value under an alpha beta coordinate system; z is a radical of_αIs the output value of the alpha axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the alpha axisz_βIs the output value of the beta axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the beta axis

And the estimated value of the motor rotating speed is obtained.

The quasi-proportional resonance controller adopts a transfer function to calculate and obtain the back electromotive force estimated value, and the transfer function is as follows:

when the quasi-proportional resonant controller is digitally implemented, the following bilinear transformation is adopted for discretization:

wherein k is_pIs the proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;

the estimated value of the motor rotating speed is obtained; t is a sampling period; z is a discretized process variable, i.e., a Z-transform operator.

The transfer function of the quasi-proportional resonant controller is transformed into:

wherein:

t is the sampling period.

The quasi-proportional resonant controller of the invention contains a proportional coefficient k_pIntegral coefficient k_rAnd a cut-off frequency omega_cThree adjustable parameters that will affect the performance of the observer.

In actual operation, for the surface-mounted permanent magnet synchronous motor, parameter selection can be performed according to the following methodTaking: consider when k is_pWhen the gain is more than or equal to 1, the gain of the quasi-proportional resonant controller at each frequency point is 1 at the minimum, harmonic signals including higher harmonics near the switching frequency are amplified, and the performance of the observer is reduced. To suppress harmonics, k, in the observer at low carrier ratios_pIs selected from 0 to 1. At design time k_iAccording to the derived observer open-loop transfer function:

in the formula, R is the phase resistance of the motor winding; l is winding phase inductance, L_d＝L_q＝L；r₁+r₂＝(1+k_r/k_p)ω_c；Adopting the zero-pole cancellation idea to make r₁＝R/L，

The observer open-loop transfer function after zero-pole cancellation is:

so that:

controller bandwidth omega_cThe value of (2) is related to the fluctuation range of the rotating speed, and the bandwidth omega of the controller can be selected according to the control precision of the rotating speed_c. For example, if the rotational speed control accuracy is 5%, the bandwidth of the quasi-proportional resonant controller is selected to be

Fig. 5(a-b) show the frequency characteristics (i.e., amplitude, phase characteristics) of the quasi-proportional resonant controller of the present invention. Quasi-proportional resonant controller 16 at resonant frequency

Has larger gain and zero phase shift, thereby realizing the frequency of

Is controlled without dead-beat so that the current estimate is madeTracking the actual values i separately_α、i_βTo obtain accurate back electromotive force estimation value

FIG. 6(a-b) is a comparison of current observation waveforms of the adaptive observer based on quasi-proportional resonance and the conventional sliding-mode observer according to the present invention; FIG. 7(a-b) is a comparison of the back emf observed waveforms of the quasi-proportional resonance based adaptive observer of the present invention and a conventional sliding mode observer; FIG. 8(a-b) is a comparison of the position estimation error of the adaptive observer based on quasi-proportional resonance of the present invention and a conventional sliding-mode observer; fig. 9(a-b) is a comparison of the speed estimation error of the adaptive observer based on quasi-proportional resonance of the present invention and a conventional sliding-mode observer. Therefore, by adopting the adaptive observer based on the quasi-proportional resonance, the buffeting of the observed values of the current and the counter potential is reduced, the estimation errors of the position and the speed are reduced, and the estimation accuracy of the position and the speed of the system is improved.

As shown in fig. 10, the present invention further provides a method for estimating a position of a permanent magnet synchronous motor based on a quasi-proportional resonance adaptive observer, comprising the following steps:

s1, calculating according to the voltage, the counter potential estimated value and the motor rotating speed estimated value to obtain a current observed value;

s2, comparing the current observation value with a current detection value to obtain a current difference value;

s3, calculating according to the current difference value and the motor rotating speed estimated value to obtain the back electromotive force estimated value;

and S4, acquiring the motor rotating speed estimated value and the motor rotor angle according to the counter electromotive force estimated value.

Further, the step S1 is to calculate according to the voltage, the back electromotive force estimated value and the motor rotation speed estimated value to obtain a current observed value, and includes:

wherein, R is the phase resistance of the motor winding; l is winding phase inductance;

is an alpha axis current observed value under an alpha beta coordinate system;

is a beta axis current observed value under an alpha beta coordinate system; z is a radical of_αIs the output value of the alpha axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the alpha axis

z_βIs the output value of the beta axis of the quasi-proportional resonance control unit, which is equal to the back electromotive force estimated value of the beta axis

And the estimated value of the motor rotating speed is obtained.

Step S3 is calculated according to the current difference and the motor speed estimation value to obtain the back electromotive force estimation value, and includes:

the quasi-proportional resonance controller obtains the estimated back emf value by adopting a transfer function calculation, wherein the transfer function is as follows:

wherein k is_pIs a stand forA proportionality coefficient of the quasi-proportional resonant controller; k is a radical of_rIs the integral coefficient of the quasi-proportional resonant controller; omega_cIs the cut-off frequency of the quasi-proportional resonant controller;

the estimated value of the motor rotating speed is obtained; t is a sampling period; z is a discretized process variable, i.e., a Z-transform operator.

In specific application, the method for estimating the position of the permanent magnet synchronous motor of the adaptive observer based on the quasi-proportional resonance is realized by the adaptive observer based on the quasi-proportional resonance, and the adaptive observer based on the quasi-proportional resonance can comprise a current state observer, a comparator, a quasi-proportional resonance controller and a phase-locked loop. The input of the current state observer is alpha beta axis voltage, an alpha beta axis back electromotive force estimated value and a rotating speed estimated value, after the difference between the observed current value and the detected current value is obtained, the estimated back electromotive force is obtained through a quasi-proportional resonance controller, and then the estimated back electromotive force is input into a phase-locked loop to obtain a motor rotating speed estimated value and a motor rotor angle.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.