Research On Permanent Magnet Synchronous Control System Based On The Method Of High-frequency Signal Injection And Sliding Mode Observer

There are many advantages in permanent magnet synchronous motor(PMSM),such aslight weight，small size, small loss, simple structure, reliable operation, high efficiency and soon. At the same time, it can conveniently be maintained and controlled. Compared with theinduction motor, the structure of its rotor is largely simplified, and the stability of the motor isenhanced when it is running. There are many advantages in PMSM, such as high precision,wide speed range and high dynamic property, so the vector control system of PMSM has beenwidely applied in industry, agriculture, national defense and other fields.In this paper, vector control system of PMSM is structured based upon the method ofid=0control and vectored control of rotor flux. This measure possesses simple controlalgorithm, it can not only accomplish control of decoupling to the stator current and rotor flux,but also achieve the ratio of torque to current to the maximum. In order toavoid the trouble which is brought because of the use of speed sensor, and save the cost, themethod of high-frequency signal injection and sliding mode observer is used at the same timeto estimate the rotor position, which is used to make the motor normally operate. The methodof spin high-frequency signal injection can maintain the following performance well in widespeed range, the rotor position estimated by this method can accurately reflect the actualposition of the rotor. However, the error of the rotor speed will increase when the rotor speedincrease. And the error in the method of sliding mode observer will increase when running inlow speed, meanwhile, the error in this method will reduce when running in high speed. Inorder to make up each other, a novel method of estimating rotor position control system isstructured in this paper. That is to say, the method of high-frequency signal injection is used toguarantee the measurement accuracy of the rotor position in low speed, while the method ofsliding mode observer is used to guarantee dynamic performance in high speed. To solve theproblem of the high-frequency jitter, which is caused by the discontinuous control ofBang-bang in the sliding mode observer, the continuous saturation function is used insteadof the discontinuous switching function.Finally, the method of sliding mode observer and the method ofhigh-frequency signal injection and sliding mode observer are analyzed in theMatlab/Simulink environment. The results of simulation show that the method ofhigh-frequency signal injection and sliding mode observer can not only be applied in lowspeed, but also be applied in high speed, it greatly extend the application of the method aboutestimating the rotor speed. It not only avoid the poor performance when using the method ofsliding mode observer in low speed, but also avoid the poor performance when using the method of high-frequency signal injection in high speed. The experiment verifies it very well.