阅读说明：本技术 一种自适应滑模增益永磁同步电机无速度传感器控制方法 (Speed sensorless control method of self-adaptive sliding mode gain permanent magnet synchronous motor ) 是由 申永鹏 王延峰 叶晨光 胡智宏 刘普 杨小亮 张志艳 邱洪波 赵俊 杜海明 武洁 于 2020-07-23 设计创作，主要内容包括：本发明公开了一种自适应滑模增益永磁同步电机无速度传感器控制方法,包括以下步骤：采集被测电机的三相定子电流,分别为<Image he="46" wi="30" file="DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>、<Image he="42" wi="28" file="DEST_PATH_IMAGE004.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>、<Image he="39" wi="27" file="DEST_PATH_IMAGE006.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>；并通过Clark变换得到测量电流<Image he="43" wi="27" file="DEST_PATH_IMAGE008.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>、<Image he="45" wi="31" file="DEST_PATH_IMAGE010.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>；利用电机数学模型计算出观测电流值<Image he="51" wi="39" file="DEST_PATH_IMAGE012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>、<Image he="47" wi="35" file="DEST_PATH_IMAGE014.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,计算滑模增益自适应率K,并将滑模增益自适应率应用到S2中的电机数学模型中用来校正测量电流值和观测电流值之间的电流误差值<Image he="37" wi="27" file="DEST_PATH_IMAGE016.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,使其逐渐接近于零。本发明专利采用的自适应滑模增益观测器可以使被测电机实时地配置自适应增益因子,更好的改善滑模抖振现象,提高了观测精度；同时自适应滑模增益观测器得到的电流曲线更加平滑,抖振含量较少,运行更加稳定。(The invention discloses a speed sensorless control method of a self-adaptive sliding mode gain permanent magnet synchronous motor, which comprises the following steps of: collecting three-phase stator currents of a tested motor respectively 、 、 (ii) a And obtaining the measured current by Clark transformation 、 (ii) a Calculating the observed current value by using a motor mathematical model 、 Calculating a sliding mode gain adaptation rate K, and applying the sliding mode gain adaptation rate to the mathematical model of the motor in S2 for correcting the current error value between the measured current value and the observed current value Gradually approaching zero. The adaptive sliding mode gain observer adopted by the invention can enable a measured motor to be configured with an adaptive gain factor in real time, better improve the phenomenon of sliding mode buffeting and improve the observation precision; meanwhile, a current curve obtained by the adaptive sliding mode gain observer is smoother, buffeting content is less, and operation is more stable.)

1. A speed sensorless control method of a self-adaptive sliding mode gain permanent magnet synchronous motor is characterized by comprising the following steps:

s1, collecting three-phase stator currents of the tested motor, wherein the three-phase stator currents are i_a、i_b、i_c(ii) a And obtaining the measurement current i through Clark transformation_α、i_β；

S2, utilizing the number of motorsThe observed current value i is calculated by the mathematical model_α ^*、i_β ^*，

S3, calculating a sliding mode gain adaptive rate K, and applying the sliding mode gain adaptive rate to the motor mathematical model in S2 to correct the current error value between the measured current value and the observed current value to gradually approach zero.

2. The adaptive sliding mode gain permanent magnet synchronous motor speed sensorless control method according to claim 1, wherein the motor mathematical model formula in S2 is:

3. the method for controlling the non-speed sensor of the adaptive sliding mode gain permanent magnet synchronous motor according to claim 1 or 2, wherein the calculation formula of the sliding mode adaptive rate K in S3 isWherein

4. An adaptation as claimed in claim 1The control method of the sliding mode gain permanent magnet synchronous motor without the speed sensor is characterized in that a calculation formula of a current error value in S3 is as follows:

5. the adaptive sliding mode gain PMSM speed sensorless control method of claim 3, wherein the effective value of current over the entire cycle number

Technical Field

The invention belongs to the technical field of motor control, and particularly relates to a speed sensorless control method of a self-adaptive sliding mode gain permanent magnet synchronous motor.

Background

A control method of a permanent magnet synchronous motor self-adaptive sliding mode observer is a very common use method in the control of the existing permanent magnet synchronous motor. The sliding-mode observer is a dynamic system that derives state variable estimates from measured values of external variables (input variables and output variables) of the system, also known as a state reconstructor. The sliding-mode observer not only provides practical possibility for the technical realization of state feedback, but also is practically applied to many aspects of control engineering. The sliding mode observer can obtain an estimated value of the internal state of a given system by measuring the input and the output of the actual system. The sliding-mode observer uses nonlinear high-gain feedback to force the estimated state to approach the hyperplane, so that the estimated output is equal to the measured output. The performance of the control system is tested by building a control experiment platform of the self-adaptive sliding mode observer of the permanent magnet synchronous motor, collecting and analyzing related data according to the operation of the motor under different working conditions. As shown in fig. 1, the conventional control method of the adaptive sliding mode observer is composed of a measured current output link of a motor, an observed current output link estimated by a motor model, and a sliding mode adaptive control part, and an error value is fed back to the motor model in a closed-loop manner. The existing control method of the permanent magnet synchronous motor self-adaptive sliding mode observer has the following defects: 1. the sliding mode buffeting existing in the sliding mode observation control system is large; 2. the phase current output is unstable, and a sawtooth waveform exists around the peak value of the phase current curve; 3. the observation precision of the sliding-mode observer is low; 4. a fixed adaptation factor is employed throughout the system, however, the adaptation factor is not made to vary in accordance with changes in the control system using an adaptive sliding mode gain.

Disclosure of Invention

The invention aims to provide a speed sensorless control method of a self-adaptive sliding mode gain permanent magnet synchronous motor, which can better improve the sliding mode buffeting phenomenon and improve the observation precision.

In order to achieve the purpose, the invention adopts the following technical scheme:

a speed sensorless control method of a self-adaptive sliding mode gain permanent magnet synchronous motor comprises the following steps: s1, collecting three-phase stator currents of the motor to be detected through a current sensor, wherein the three-phase stator currents are i_a、i_b、i_c(ii) a And the three-phase stator current is converted by Clark to obtain the measured current i_α、i_β(ii) a Finally, outputting the measured current;

s2, calculating the observed current value i by using a motor mathematical model_α ^*、i_β ^*，

S3, calculating a sliding mode gain adaptive rate K, and applying the sliding mode gain adaptive rate to the motor mathematical model in S2 to correct the current error value between the measured current value and the observed current value to gradually approach zero.

Further, in S2, the mathematical model formula of the motor is:wherein i_α ^*、i_β ^*Respectively, are the observed current components of the current,

respectively, a back electromotive force component, Z_α、Z_βIs the output correction factor component of the sliding mode controller, R is the stator resistance, L is the stator inductance, u is the output correction factor component of the sliding mode controller_α、u_βStator voltages on an alpha coordinate system and a beta coordinate system;estimating the observed current value i by using a motor mathematical model_α ^*、i_β ^*Then, the self-adaptive gain factor is fed back to the motor model, the difference value of the measured current and the observed current is judged, and the difference value of the measured current and the observed current is corrected through the self-adaptive gain factor to gradually approach zero, so that the observed current is closer to the measured current.

Further, the sliding mode observer is required to control when the sliding mode gain adaptive rate K is calculated in S3, when the sliding mode observer is adopted to control, it is observed that a large ripple chattering appears in an output waveform of the motor current in a sampling frequency period, the chattering is a real error existing between an observed current and a measured current when the permanent magnet synchronous motor operates, and the formula is

In order to overcome the current error existing in the control system, a sliding mode gain adaptive factor is introduced, an output error is utilized to drive an adaptive structure, a sliding mode gain adaptive rate K is obtained, and the sliding mode gain adaptive rate K is obtained according to a formula

The current output error is made to vary with the adaptation rate. The parameters to be estimated can be continuously corrected under the action of the self-adaptive rate, so that the output error of the sliding mode observation model tends to zero.

Essentially, a constant boundary layer thickness is the root cause for poor performance of the saturation function. Therefore, in order to improve the control performance of the saturation function, a continuously variable adaptive coefficient is required to control the change of the function, so that the thickness of the boundary layer can be narrowed along with the convergence of the system state trajectory, and finally the boundary layer is overlapped with the switching plane, and the aim of converging the system trajectory on the given switching plane is fulfilled. When the control function is continuously changed, an approach angle is formed between the control function and the abscissa axis, the approach angle is an included angle between the system state track and the switching plane and is reduced along with the approach of the state track to the switching plane, so that the approach angle is the most intuitive variable for measuring the convergence degree of the state track, and the approach angle is used as a self-adaptive coefficient of function change to construct a boundary layer thickness function.

The internal relation among the effective value of the current, the current error value and the adaptive factor is found out by calculating the effective value of the measured current, and the sliding mode gain adaptive rate is obtained, so that the error amount of the current in the control system is effectively reduced.

The calculation formula of the sliding mode self-adaptive rate K in S3 is

Wherein

The effective value of the current in the whole period number. Where r is the adaptive rate coefficient of the functional relation. Using current error value () and current effective valueThe change relation exists between the sliding mode control system and the sliding mode control system, the value of the coefficient r is determined, and the self-adaptive rate is always controlled within a fixed range, so that the error between the measured current and the observed current is effectively overcome, and the whole sliding mode control system is in a stable and accurate observation state.

Further, the effective value of the current in the whole period number

The calculation formula of (2) is as follows:

wherein _jIs a data sample index; p is the number of periodic cycles; m is the sampling number in the period defined by the filtered synchronous signal; m_pThe number of sampling points in the cycle number; m is an initial sampling point index;_mpis the index of the initial sampling point of the cycle number; n is the number of cycles (defined by the selected sync source signal);is the effective value of the current in each period.

Effective value of phase current under different working conditions

The permanent magnet synchronous motor can be operated under different working conditions according to the formula in the simulation process, so that the operation is solved.

According to the method, the sliding mode gain self-adaptive factor is introduced by utilizing the current error value between the measured current and the observed current, so that the sliding mode gain self-adaptive rate K is obtained, the self-adaptive gain factor can change along with the magnitude of the current error in the control system, the current error can be better reduced and approaches to zero, the measured current is closer to the actual current, and the sliding mode buffeting phenomenon is better improved.

The method of the invention has the following advantages:

firstly, compare in traditional sliding mode observer control method. The adaptive sliding mode gain observer adopted by the invention can enable the measured motor to be configured with the adaptive gain factor in real time, better improve the phenomenon of sliding mode buffeting and improve the observation precision.

Compared with the traditional sliding mode observer, the self-adaptive sliding mode gain observer has the advantages that the obtained current curve is smoother, the buffeting content is less, and the operation is more stable.

Drawings

FIG. 1 is a schematic diagram of a control structure of a conventional permanent magnet synchronous motor adaptive sliding mode observer;

FIG. 2 is a diagram of a non-speed sensor control design for an adaptive sliding film gain PMSM according to the present invention;

FIG. 3 is a control flow chart of the present invention;

FIG. 4 is a waveform of a stator current at a rotation speed of 1500 r/min;

FIG. 5 shows the waveform changes of the actual rotation speed and the observed rotation speed at the steady state rotation speed of 1500 r/min;

FIG. 6 shows the waveform and error of the rotor position at 1500 r/min.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, 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.

As shown in fig. 2, a method for controlling a speed sensorless adaptive sliding mode gain permanent magnet synchronous motor. The method comprises the following steps: the motor error correction method comprises a measuring current output link of a motor, an observation current output link estimated by a motor model and a self-adaptive sliding mode gain control part, wherein in order to enable the measuring current to be matched with the observation current, an error value is fed back to the motor model in a closed-loop mode, so that the current error value is corrected. The specific embodiment is implemented as follows:

and S1, outputting the measured current of the motor. The three-phase stator current of the tested motor is acquired through a current sensor and is i respectively_a、i_b、i_c(ii) a And the three-phase stator current is converted by Clark to obtain the measured current i_α、i_β(ii) a Finally, outputting the measured current;

and S2, estimating an observation current output link by the motor model. Calculating an observed current value i by using a motor mathematical model_α ^*、i_β ^*，

The mathematical model formula of the motor is as follows:wherein i_α ^*、i_β ^*Respectively, are the observed current components of the current,

respectively, a back electromotive force component, Z_α、Z_βIs the output correction factor component of the sliding mode controller, R is the stator resistance, L is the stator inductance, u is the output correction factor component of the sliding mode controller_α、u_βStator voltages on an alpha coordinate system and a beta coordinate system;

according to the formula, the self-adaptive gain factor is fed back to the motor model through the sliding mode gain self-adaptive rate K, the difference value of the measured current and the observed current is judged, and the difference value of the measured current and the observed current is corrected through the self-adaptive gain factor to enable the difference value to gradually approach zero.

And S3, adaptive sliding mode gain control. Calculating the self-adaptive rate K of the sliding mode gain, and controlling by using a sliding mode observer during calculation according to the formulaWhereinThe effective value of the current in the whole period number,where r is the adaptive rate coefficient of the functional relation. Using current error value () and current effective valueThe change relation exists between the current and the current, the value of the coefficient r is determined, the self-adaptive rate is always controlled in a fixed range, the error between the measured current and the observed current is effectively overcome, and the whole sliding mode control is realizedThe system is in a stable and accurate observation state.

Effective value of current in the whole periodThe calculation formula of (2) is as follows:

whereinj is the data sample index; p is the number of periodic cycles; m is the sampling number in the period defined by the filtered synchronous signal; m_pThe number of sampling points in the cycle number; m is an initial sampling point index; m is_pIs the index of the initial sampling point of the cycle number; n is the number of cycles (defined by the selected sync source signal);

is the effective value of the current in each period.

After calculating the self-adaptive rate K of the sliding mode gain, the formula is used

The sliding mode gain adaptation rate is applied to the mathematical model of the motor in S2 to correct the current error value between the measured current value and the observed current value to gradually approach zero. At the moment, the sliding mode gain factor can be changed according to the change of the control system, and is not fixed, so that the observation precision of the system is better improved.

Fig. 3 shows a specific control flow chart of the present invention, wherein the stator voltage value of the motor is inputted into the computer input interface before the steps in fig. 2 are implemented, the computer sends the electronic voltage value to the motor controller, and the controller drives the motor to operate and obtains the measured current value through the current sensor.

In order to verify the speed sensorless control system of the permanent magnet synchronous motor based on the self-adaptive sliding mode observer, the method disclosed by the invention is adopted, and a simulation model is built according to the control system, wherein the main specification parameters of the adopted PMSM are shown in table 1.

TABLE 1 PMSM Specification parameters

The experimental results are as follows:

the A-phase stator current waveform is obtained by using an adaptive sliding mode gain observer and a traditional sliding mode observer at the rotating speed of 1500r/min as shown in figure 4. According to the simulation result, the buffeting amplitude of the simulation waveform obtained by the adaptive sliding mode gain observer is small under a certain rotating speed, and the buffeting amplitude is effectively weakened.

The motor rotating speed waveform at the steady state is obtained by using an adaptive sliding mode gain observer and a traditional sliding mode observer at the rotating speed of 1500r/min as shown in figure 5. By comparison, the rotating speed error obtained by the traditional sliding mode observer is at least 8r/min, the rotating speed error obtained by the adaptive sliding mode gain observer is 5r/min, and meanwhile, the rotating speed curve obtained by the adaptive sliding mode gain observer has less buffeting content and higher observation precision.

FIG. 6 shows the target rotor position, observed rotor position, and rotor position error waveforms obtained using an adaptive sliding mode gain observer and a conventional sliding mode observer at a rotation speed of 1500 r/min. According to the waveform comparison, the buffeting amplitude and the rotor position error of the observed rotor position of the traditional sliding mode observer are large, the self-adaptive sliding mode gain observer effectively improves the observation precision, weakens the buffeting amplitude, reduces the rotor position error and has good dynamic performance.