Research On Rotor Speed Identification Method For Permanent Magnet Synchronous Motor Based On Improved Model Reference Adaptive System

Permanent magnet synchronous motor (PMSM) with its advantages of smallvolume, high efficiency, simple rotor structure, reliable operation, are widely used inelectric drive field. In recent years, using the vector control technology caneffectively improve the dynamic performance of PMSM speed control system and theresponse speed of PMSM, the speed control performance of PMSM can be comparablewith the DC motor’s.In this paper, the rotor field-oriented and id=0control are adopted in vectorcontrol system of surface mounted PMSM, this control method is simple, can realizeflux decoupling control of stator current and rotor flux, when applied in surfacemounted permanent magnet synchronous motor, the method can achieve the maximumratio of torque to current.According to the installation of speed sensor increases the cost, volume, lowreliability, easily influenced by the environment and other defects, the modelreference adaptive system (MRAS) based on stator flux observer is adopted toestimate the rotor speed and position. The method applied to vector control system ofpermanent magnet synchronous motor has good dynamic respo nse performance,strong robustness to disturbance of the motor parameters and uncertain factors, canestimate the motor rotor position and speed effectively when the motor is at middleand high speed, but the traditional MRAS brings error accumulation and DC biasproblems that seriously affect the estimation accuracy, which is caused by the pureintegrator flux observation. the situation is particularly evident at low speed.Therefore, aiming at the existing problems of traditional MRAS, this paper putsforward an improved MRAS method, Introducing the high-pass filter links toeliminate the pure integral effect in the voltage model, while introdu cing the samefilter in the current model to balance the phase and amplitude deviation caused by thepure integral, which can basically eliminate the influence of DC bias. besides, Avolume of feedback is used in stator flux observation, it can obtain an error valuewhen the stator flux value of the voltage model compared with the flux value of thecurrent model, then the error can be corrected by PI regulator, so that greatlyimproves the accuracy of flux observation.Finally, the simulation models of speed identification system of permanentmagnet synchronous motor based on traditional MRAS and improved MRAS are built in the Matlab/Simulink environment. The simulation results show that the improvedMRAS method greatly correct the error of the traditional MRAS caused by integral atlow speed, it has good recognition precision and dynamic performance in vectorcontrol system of PMSM. can accurately identify the rotor speed and position. Andthen the experimental platform for experimental verification is built, experimentalresults show the feasibility of rotor speed and position identification by the improvedMRAS.