阅读说明：本技术 一种采用改进滑模观测器的永磁同步电机转子位置和速度估算系统及方法 (Permanent magnet synchronous motor rotor position and speed estimation system and method adopting improved sliding-mode observer ) 是由 安群涛 张建秋 安琦 刘兴亚 李帅 谢成龙 于 2018-07-25 设计创作，主要内容包括：本发明提出了一种采用改进滑模观测器的永磁同步电机转子位置和速度估算系统及方法,属于电机控制技术领域。所述系统采用由电流状态观测器、比较器、改进复矢量PI控制器和锁相环组成滑模观测器,电流状态观测器的输入为α和β轴电压、α和β轴反电势估计值和转速估计值,观测出的电流值与检测的电流值求差后,经过改进复矢量PI控制器得到估计的反电势,再输入到锁相环得到转子位置和速度。所述系统及方法提高了观测器的稳定性。(The system adopts a sliding mode observer consisting of a current state observer, a comparator, an improved complex vector PI controller and a phase-locked loop, wherein the current state observer inputs α and β shaft voltages, α and β shaft back electromotive force estimated values and rotating speed estimated values, the estimated back electromotive force is obtained through the improved complex vector PI controller after the difference between the observed current value and the detected current value is solved, and then the estimated back electromotive force is input to the phase-locked loop to obtain the position and the speed of the rotor.)

1. A permanent magnet synchronous motor rotor position and speed estimation system adopting an improved sliding-mode observer is characterized in that the system adopts a sliding-mode observer which comprises a current state observer, a comparator, an improved complex vector PI controller and a phase-locked loop; the signal output end of the current state observer is connected with the signal input end of the comparator; the signal output end of the comparator is connected with the signal input end of the improved complex vector PI controller; the signal output end of the improved complex vector PI controller is connected with the signal input end of the phase-locked loop; and the feedback signal output end of the improved complex vector PI controller is connected with the feedback signal input end of the current state observer.

2. The PMSM rotor position and speed estimation system of claim 1, wherein the PMSM rotor position and speed estimation system adjusts for deviations between current observations and current detections by the modified complex vector PI controller, the modified complex vector PI controller being of the form:

wherein, K_p、K_iRespectively a proportional coefficient and an integral coefficient of the improved complex vector PI controller; s is a laplace operator;

3. The PMSM rotor position and speed estimation system of claim 1, wherein the modified complex vector PI controller obtains back emf estimates for the α and β axes through an estimate model that is:

wherein the content of the first and second substances,

4. A permanent magnet synchronous motor rotor position and speed estimation method adopting an improved sliding mode observer is characterized by comprising the following steps:

firstly, inputting the α and β shaft voltages of the permanent magnet synchronous motor into a current state observer, and processing by the current state observer to obtain α and β shaft current observed values

Secondly, current observed values of the α and β axes

Thirdly, deviating the current of the α and β axes by delta i_α、Δi_βInputting the input signal into an improved complex vector PI controller; deviation of the current by Δ i_α、Δi_βMultiplying with improved complex vector PI controller, and substituting into motor rotor angular frequencyFurther obtain the back electromotive force estimated values of α and β axes

Fourthly, estimating the back electromotive force of the α and β axes

5. The method of estimating rotor position and speed of a PMSM according to claim 4, wherein the modified complex vector PI controller is of the form:

wherein, K_p、K_iRespectively a proportional coefficient and an integral coefficient of the improved complex vector PI controller; s is a laplace operator;

6. The PMSM rotor position and speed estimation method of claim 4, wherein the modified complex vector PI controller obtains back emf estimates for the α and β axes through an estimate model that is:

wherein the content of the first and second substances,estimated back-emf on the α and β axes, respectively,. DELTA.i_α、Δi_βα and β axis current offsets respectively,

Technical Field

The invention relates to a system and a method for estimating the position and the speed of a permanent magnet synchronous motor rotor by adopting an improved sliding-mode observer, belonging to the technical field of motor control.

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 extracts the rotor angle and speed information from the motor back electromotive force or flux linkage related to the rotor angle through real-time observation, and the observer is a common method for estimating the position and speed of a middle-high speed section, and the methods comprise a sliding mode observer, a Longbeige observer, a self-adaptive 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 many researchers have proposed methods such as saturation function to suppress the chattering, the methods cannot be eliminated.

Disclosure of Invention

The invention provides a system and a method for estimating the position and the speed of a permanent magnet synchronous motor rotor by adopting an improved sliding mode observer, aiming at solving the problems of buffeting of the permanent magnet synchronous motor sliding mode position observer and phase delay caused by adopting a low-pass filter in the traditional estimation system, and comprising the following steps:

a permanent magnet synchronous motor rotor position and speed estimation system adopting an improved sliding-mode observer adopts the following technical scheme:

the system adopts a sliding-mode observer, the sliding-mode observer comprises a current state observer, a comparator, an improved complex vector PI controller and a phase-locked loop, the signal output end of the current state observer is connected with the signal input end of the comparator, the signal output end of the comparator is connected with the signal input end of the improved complex vector PI controller, the signal output end of the improved complex vector PI controller is connected with the signal input end of the phase-locked loop, the feedback signal output end of the improved complex vector PI controller is connected with the feedback signal input end of the current state observer, the input of the current state observer is α, β shaft voltage, α and β shaft back electromotive force estimated values and rotating speed estimated values, after the difference between the observed current value and the detected current value is obtained, the estimated back electromotive force is obtained through the improved complex vector PI controller, and then the estimated back electromotive force is input to the phase-locked loop to obtain the position and the speed.

Further, the PMSM rotor position and speed estimation system adjusts a deviation between the current observation value and the current detection value through the modified complex vector PI controller, which is in the form of:

wherein, K_p、K_iRespectively a proportional coefficient and an integral coefficient of the improved complex vector PI controller; s is a laplace operator;

the angular frequency of the motor rotor is output by a phase-locked loop; omega_cIs the bandwidth frequency; j is an imaginary unit.

The improved complex vector PI controller is an improvement of the following traditional complex vector PI controllers:

further, the modified complex vector PI controller obtains estimated values of back electromotive forces of the α and β axes through an estimated value model which is:

wherein the content of the first and second substances,

estimated back-emf on the α and β axes, respectively,. DELTA.i_α、Δi_βα and β axis current offsets respectively,

observed values of α and β axis currents, i, respectively_α、i_βα and β axis current detection values, respectively.

A permanent magnet synchronous motor rotor position and speed estimation method adopting an improved sliding-mode observer adopts the following technical scheme:

the method for estimating the position and the speed of the rotor of the permanent magnet synchronous motor comprises the following steps:

firstly, inputting the α and β shaft voltages of the permanent magnet synchronous motor into a current state observer, and processing by the current state observer to obtain α and β shaft current observed values

Secondly, current observed values of the α and β axes

Input to a comparator where the current observed through the α and β axesThe current detection values i of α and β of the α and β axes_α、i_βComparing to obtain α and β axis current deviation delta i_α、Δi_β；

Thirdly, deviating the current of the α and β axes by delta i_α、Δi_βInputting the input signal into an improved complex vector PI controller; deviation of the current by Δ i_α、Δi_βMultiplying with improved complex vector PI controller, and substituting into motor rotor angular frequency

Further obtain the back electromotive force estimated values of α and β axes

Fourthly, estimating the back electromotive force of the α and β axes

And inputting the signals into a phase-locked loop, and obtaining a rotor position estimated value and a speed estimated value of the magnetic synchronous motor through phase-locked loop processing.

Further, the improved complex vector PI controller is of the form:

wherein, K_p、K_iRespectively a proportional coefficient and an integral coefficient of the improved complex vector PI controller; s is a laplace operator;

the angular frequency of the motor rotor is output by a phase-locked loop; omega_cIs the bandwidth frequency; j is an imaginary unit.

The improved complex vector PI controller is an improvement of the following traditional complex vector PI controllers:

further, the modified complex vector PI controller obtains estimated values of back electromotive forces of the α and β axes through an estimated value model which is:

wherein the content of the first and second substances,

estimated back-emf on the α and β axes, respectively,. DELTA.i_α、Δi_βα and β axis current offsets respectively,

observed values of α and β axis currents, i, respectively_α、i_βα and β axis current detection values, respectively.

The invention has the beneficial effects that:

the system and the method for estimating the position and the speed of the permanent magnet synchronous motor rotor by adopting the improved sliding mode observer replace a switching function and a low-pass filter in the traditional sliding mode observer by an improved complex vector PI controller on the basis of the traditional sliding mode observer, and achieve the purpose of eliminating buffeting and phase delay. According to the system and the method for estimating the position and the speed of the permanent magnet synchronous motor rotor by adopting the improved sliding-mode observer, a low-pass filter is omitted, phase delay caused by the low-pass filter is avoided, and the position and speed estimation accuracy of the permanent magnet synchronous motor is improved. Compared with the traditional PI controller, the complex vector PI controller is equivalent to a PI controller

Based on the center frequency is shifted to the right

Making the complex vector PI controller at the center frequency

Where the gain is infinite and the phase shift is zero, thus achieving a frequency of

No-static control of the signal of (1); but has the problems of difficult parameter selection, poor stability and the like. The improved complex vector PI controller designed by the invention increases the controller bandwidth on the basis of the traditional complex vector PI controller, is suitable for the fluctuation of the rotating speed, and improvesThe stability of the observer is improved.

Drawings

FIG. 1 is a block diagram of an improved sliding mode observer of the present invention.

Fig. 2 is a structural view of a conventional sliding-mode observer.

Fig. 3 is a frequency characteristic of a conventional complex vector PI controller.

Fig. 4 shows the frequency characteristic of the improved complex vector PI controller of the present invention.

Fig. 5 is a block diagram of an improved complex vector PI controller of the present invention.

Fig. 6 is a block diagram of a phase locked loop according to the present invention.

Fig. 7 shows a back electromotive force observation value, a position and speed observation value, and a position and speed observation error of a permanent magnet synchronous motor using a conventional sliding-mode observer.

Fig. 8 shows a switching function of the sliding-mode observer by replacing a back permanent magnet synchronous motor back electromotive force observation value, a position and speed observation value, and a position and speed observation error with a conventional complex vector PI controller.

Fig. 9 shows a back electromotive force observation value, a position and speed observation value, and a position and speed observation error of the permanent magnet synchronous motor of the improved sliding-mode observer according to the present invention.

Detailed Description

The present invention will be further described with reference to the following specific examples, but the present invention is not limited to these examples.