阅读说明：本技术 一种表贴式永磁同步电机无传感器控制方法 (Surface-mounted permanent magnet synchronous motor sensorless control method ) 是由 彭思齐 贺旻逸 于 2019-10-08 设计创作，主要内容包括：本发明公开了一种表贴式永磁同步电机无传感器控制方法,针对传统滑模控制所存在的抖动和谐波干扰等问题,提出一种滑模控制和基于自适应滤波器与正交锁相环相结合的滑模观测器相结合的控制方法。首先将滑模速度控制代替传统的PI控制来避免参数调节时出现的扰动,提高了电机运行时抗扰动性,一定程度提高了鲁棒性；接下来根据电机数学模型构建出滑模观测器,利用改进后的滑模观测器观测转子位置后使用自适应滤波器滤除反电动势中大量谐波,通过正交锁相环得到的信息进行自适应的调节带通截止频率,从而达到提高位置和转速的估计精度。(The invention discloses a sensorless control method of a surface-mounted permanent magnet synchronous motor, and provides a control method combining sliding mode control and a sliding mode observer based on combination of an adaptive filter and an orthogonal phase-locked loop aiming at the problems of jitter, harmonic interference and the like in the traditional sliding mode control. Firstly, the sliding mode speed control replaces the traditional PI control to avoid disturbance during parameter adjustment, so that the disturbance resistance of the motor during operation is improved, and the robustness is improved to a certain extent; and then, a sliding mode observer is constructed according to a motor mathematical model, a large number of harmonic waves in back electromotive force are filtered by using an adaptive filter after the position of the rotor is observed by using the improved sliding mode observer, and the band-pass cut-off frequency is adaptively adjusted through information obtained by an orthogonal phase-locked loop, so that the estimation precision of the position and the rotating speed is improved.)

1. A surface-mounted permanent magnet synchronous motor sensorless control method is characterized by comprising the following steps:

(1) establishing a sliding mode speed control expression based on an alpha beta coordinate;

(2) according to a mathematical model of the surface-mounted permanent magnet synchronous motor under an alpha beta coordinate, taking an observation error of a stator current as a sliding mode surface, and writing a sliding mode current observer equation in a row;

(3) because the back electromotive force contains a large amount of harmonic waves and buffeting, the accuracy of the speed and position estimation of the rotor can be seriously influenced, and an adaptive synchronous filter is proposed to filter the back electromotive force;

(4) the rotating speed and rotor position information obtained by the traditional sliding mode observer contains a large amount of harmonic waves and buffeting, and the rotating speed and the rotor position which are more accurate and smaller in buffeting are obtained through the orthogonal phase-locked loop.

2. The sensorless control method of a surface-mounted permanent magnet synchronous motor according to claim 1, wherein the sliding mode speed control is combined with a sliding mode observer based on an adaptive filter and a quadrature phase-locked loop.

3. The sensorless control method of the surface-mounted permanent magnet synchronous motor according to claim 1, wherein the expression is controlled based on the sliding mode speed in α β coordinate in step (1) as follows:

4. the sensorless control method of the surface-mounted permanent magnet synchronous motor according to claim 2, wherein the sliding mode speed control is combined with a sliding mode observer based on an adaptive filter and a quadrature phase-locked loop, and the method is characterized in that the input of the speed controller of the sliding mode controller module is external speed given and a permanent magnet synchronous motor rotor speed signal output by the quadrature phase-locked loop module in the sliding mode observer module, the rotating speed error is calculated by a sliding mode surface function and an approach law thereof, and a quadrature axis current given signal obtained by calculation is used as the output of the speed controller module; the input of the later-described sliding mode observer module is the stator voltage and current of the permanent magnet synchronous motor under the two-phase static coordinate, the back electromotive force estimated value under the two-phase static coordinate system is output to the adaptive filter module for filtering, and then the back electromotive force estimated value is output to the orthogonal phase-locked loop module and then the rotor position and speed estimated value of the permanent magnet synchronous motor is output.

Technical Field

The invention relates to the field of permanent magnet synchronous motor control, in particular to a surface-mounted permanent magnet synchronous motor vector control method based on double sliding mode surfaces.

Background

The permanent magnet synchronous motor has the characteristics of high torque ratio, high efficiency, high power density and the like, and is widely applied to a high-performance speed regulating system. Accurate information of the speed and the position of the motor rotor is obtained through installing a sensor in engineering, so that the size and the cost of a system are increased, and the reliability of the system is reduced. Therefore, the research on the sensorless control technology of the permanent magnet synchronous motor has extremely important significance.

In recent years, the sliding mode observer is popular among people due to the characteristics of simple calculation, good robustness, easy realization and the like. However, the conventional sliding mode observer has a large buffeting value in a control system, and a phase delay problem is caused by the application of a low-pass filter. The conventional sensorless control system of the sliding mode observer cannot accurately estimate the rotating speed of the rotor at low speed, so that the application of the conventional sliding mode observer in actual control is limited in some aspects.

Disclosure of Invention

The invention aims to provide a sensorless control method of a surface-mounted permanent magnet synchronous motor, which not only greatly filters out harmonic waves existing in the information of the rotating speed and the position of a rotor, weakens buffeting of a system, but also improves the accuracy of the estimation of the rotating speed and the position information.

In order to achieve the above object, according to an aspect of the present invention, a sensorless control method for a surface-mounted permanent magnet synchronous motor is provided, which specifically includes the following steps:

(1) establishing a sliding mode speed control expression based on an alpha beta coordinate;

(2) according to a mathematical model of the surface-mounted permanent magnet synchronous motor under an alpha beta coordinate, taking an observation error of a stator current as a sliding mode surface, and writing a sliding mode current observer equation in a row;

(3) because the back electromotive force contains a large amount of harmonic waves and buffeting, the accuracy of the speed and position estimation of the rotor can be seriously influenced, and an adaptive synchronous filter is proposed to filter the back electromotive force;

(4) the rotating speed and rotor position information obtained by the traditional sliding mode observer contains a large amount of harmonic waves and buffeting, and the rotating speed and the rotor position which are more accurate and smaller in buffeting are obtained through the orthogonal phase-locked loop.

The voltage equation of the SPMSM in the stator two-phase static alpha and beta coordinate system is as follows:

and the equation of a rotor two-phase rotation dq coordinate system obtained through coordinate conversion is as follows:

in the formula u_α，u_β，u_d，u_qStator voltage α β axis and dq axis components, respectively; i.e. i_α，i_β，i_d，i_qThe components of the electron current α β axis and dq axis, respectively; r, L_dRespectively a stator resistor and an inductor; omega is the rotor speed; θ is the rotor position; psi_fA rotor permanent magnet flux linkage; p is a differential operator.

The method is characterized in that the input of a speed controller of a sliding mode controller module is external speed given and a permanent magnet synchronous motor rotor speed signal output by an orthogonal phase-locked loop module in the sliding mode observer module, a rotating speed error is calculated by a sliding mode surface function and an approximation law thereof, and a quadrature axis current given signal obtained by calculation is used as the output of the speed controller module; the input of the later-described sliding mode observer module is the stator voltage and current of the permanent magnet synchronous motor under the two-phase static coordinate, the back electromotive force estimated value under the two-phase static coordinate system is output to the adaptive filter module for filtering, and then the back electromotive force estimated value is output to the orthogonal phase-locked loop module and then the rotor position and speed estimated value of the permanent magnet synchronous motor is output.

To facilitate the design of the sliding-mode observer, the formula (2) is further changed into:

where J is the moment of inertia.

Defining a sliding mode surface function as:

s＝cx₁+x₂ (4)

wherein: c > 0 is a parameter to be designed. The derivation of equation (10) can be:

compared with the conventional sign function sgn (x), sigmoid (x) is used instead, and is defined as:

the expression for the controller is thus obtained as:

the sliding mode observer part based on the adaptive filter and the quadrature phase-locked loop is composed of the following parts: the sliding mode observer method, the adaptive filter and the quadrature phase-locked loop are improved.

Firstly, constructing a sliding mode current observer based on a mathematical model of the permanent magnet synchronous motor to obtain back electromotive force (z)_α,z_β)。

Secondly, the self-adaptive synchronous filter self-adaptively filters out harmonic waves and buffeting in the back electromotive force according to the position signal fed back by the phase-locked loop and synchronously outputs fundamental wave back electromotive force

Finally, the orthogonal phase-locked loop is based on the back electromotive force and the rotation speed omega of the fundamental wave₀ ^*And calculating the position and the speed of the rotor.

The sliding-mode observer can be designed as follows:

where k is the feedback gain.

The adaptive filter is different from a common low-pass filter and can adaptively extract the fundamental component of the back electromotive force along with the change of the estimated motor rotating speed under the synchronous condition.

The most important of which is given a value of:

b₁(t)＝δsin(ω₀t)[∫e(t)sin(ω₀t)dt] (10)

the orthogonal phase-locked loop performs normalization processing to avoid errors caused by an arc tangent function algorithm in the traditional sliding mode observer so as to achieve the effect of reducing error rotating speed and position information errors, and inputs a fundamental rotating speedTo improve the response speed of the system.

WhereinThe definition is as follows:

compared with the prior art, the invention has the beneficial effects that:

when a control system is subjected to external interference, the traditional PI control has poor disturbance resistance, and a large amount of harmonic waves and buffeting exist in the rotating speed and rotor position information obtained under a traditional sliding mode observer based on a tangent function, and large phase delay exists. The invention relates to a surface-mounted permanent magnet synchronous motor vector control method based on double sliding mode surfaces, namely sliding mode speed control is combined with a sliding mode observer based on an adaptive filter and an orthogonal phase-locked loop, the sliding mode speed control is firstly used for replacing the traditional PI control to avoid disturbance which possibly occurs during parameter adjustment, the disturbance resistance of a motor during operation is improved, and the robustness is improved to a certain extent; and then observing the position of the rotor by using the improved sliding mode sensor, filtering a large number of harmonic waves in the back electromotive force by using a self-adaptive filter, and carrying out self-adaptive adjustment on the band-pass cut-off frequency by using the orthogonal phase-locked loop according to the obtained information so as to improve the estimation precision of the position and the rotating speed.

Drawings

Fig. 1 is a structural block diagram of a surface-mounted permanent magnet synchronous motor sensorless control system based on double sliding mode surfaces.

Fig. 2 is a block diagram of an adaptive filter.

Fig. 3 is a block diagram of a quadrature phase locked loop.

FIG. 4 shows the fundamental rotation speedAnd (5) extracting a block diagram.

Fig. 5 is a diagram of an improved sliding mode observer.

Fig. 6 is a waveform diagram of the lower speed and position of a conventional sliding-mode observer.

FIG. 7 is a waveform diagram of velocity and position under the control method of the present invention

Detailed Description

The invention is further illustrated below with reference to the accompanying drawings.

As shown in fig. 1, a block diagram of a surface-mounted permanent magnet synchronous motor control system based on a double sliding mode surface includes an SPMSM (surface-mounted permanent magnet synchronous motor), a three-phase inverter module, an SVPWM (space vector pulse width modulation) module, a vector control module, a sliding mode speed controller module, a sliding mode observer module, an adaptive filter module, and an orthogonal phase-locked loop module.

The specific control process is as follows: given rotation speed omega of motor_refOmega output by the improved sliding mode observer is used as input of the sliding mode controller, and calculation results are sequentially transmitted to the next module through calculation of a sliding mode surface function in the sliding mode controller; obtaining two-phase voltage and current u after vector conversion and other modules_α，u_β，i_α，i_βInputting the signal into a sliding-mode observer to obtain back electromotive force (z)_α,z_β) At the moment, the counter electromotive force contains the information of the rotating speed and the position of the rotor, but simultaneously contains a large amount of harmonic waves and buffeting; then inputting the signal into a self-adaptive filter to filter out harmonic waves, outputting the obtained result to an orthogonal phase-locked loop, and finally obtaining the position of a rotorProviding omega for the closed loop of the rotation speed.

As shown in fig. 2, a block diagram of an adaptive filter.

The input signal is x (t), the output signal is Rotor position calculated for a quadrature phase-locked loop, an

Wherein the closed loop transfer function of the adaptive synchronous filter is:

the closed-loop characteristic equation of the method can be obtained by the formula (11):

according to the Laos-Helverz stabilization criterion, the sufficient requirements for the filter to stabilize are:

the filter is therefore stable over the full speed range (except in the quiescent state) as long as conditional expression (13) is satisfied.

As can be seen from the block diagram of FIG. 2, the filter calculates the position signal with a phase-locked loopAnd adaptively filtering harmonic waves and buffeting of the back electromotive force for reference, outputting fundamental wave back electromotive force, and calculating the position of the rotor by the phase-locked loop according to the fundamental wave back electromotive force.

As shown in FIG. 3, the quadrature phase-locked loop block diagram adds a fundamental wave rotation speed on the basis of the common phase-locked loop

The back electromotive force containing harmonic components obtained from the adaptive filter is defined as:

the back electromotive force is normalized to obtain a transfer function as follows:

in the formula, k_pIs the phase-locked loop proportional gain; k is a radical of_iIs the integral gain.

As shown in fig. 4, the fundamental rotation speedAnd (5) extracting a block diagram. By performing two-stage low-pass filtering on the counter electromotive force, and calculating by equation (15)The expression is as follows:

in the formula, #_fIs the magnetic flux of the rotor permanent magnet;respectively, back electromotive force (z)_α,z_β) The counter electromotive force after passing through the two-stage low-pass filter has small buffeting and relatively low amplitude.

As shown in fig. 5, the modified sliding-mode observer is a block diagram, which is different from the conventional sliding-mode observer in that the sliding-mode observer is combined with an adaptive filter and a quadrature phase-locked loop, so as to achieve the effects of eliminating most of harmonics and buffeting and improving estimation accuracy.

FIG. 6 is a waveform diagram of the sensorless control method of the conventional sliding mode observer when the given speed value of the motor is 1000 rad/s: (a) the actual value and the estimated value of the rotating speed are obtained, and (b) the actual value and the estimated value of the rotor position are obtained. FIG. 7 is a waveform diagram of the control method of the present invention when the motor has a set speed of 1000 rad/s: (a) the actual value and the estimated value of the rotating speed are obtained, and (b) the actual value and the estimated value of the rotor position are obtained. As can be seen from the waveform diagrams of the rotating speed and the rotor position in fig. 6 and 7, compared with the sensorless control method of the conventional sliding-mode observer, the control method provided by the invention not only greatly filters out the harmonic waves existing in the information of the rotating speed and the rotor position of the rotor, weakens the buffeting of the system, but also improves the accuracy of the estimation of the rotating speed and the position information.