Research On Rotor Position Estimation Method Of PMSM Based On Sliding Mode Observer

In comparison with other motors,PMSM has many advantages,such as compact structure,reliable perform,high efficiency,high power density,low loss and flexible shape design,which make it more and more widely used.Recently,to reduce the cost of speed control system,to improve the reliability and to extend PMSM application field,sensorless control has become a research hotspot gradually.However,the velocity,accuracy and stability of rotor estimation directly influence the performance of the sensorless control system.To solve this problem,a improved PLL is proposed to estimate the rotor position of PMSM sensorless control system.Firstly,the mathematical model is deduced respectively in α-β stationary reference frame and d-q synchronous reference frame.Analyse and study vector control with feed forward compensation.On this basis,a SMO is designed in stationary reference frame.To solve the problem of vibration in SMO,sign function is replaced by saturation function and the Matlab/Simulink model is built to verify the performance of the improved SMO.Then,the harmonic of back-electromotive force of SPMSM is analyzed,and the form of harmonic in synchronous reference frame is defined.Design a novel cascade filter in which an ANF and LPF are combined for the specific harmonic.Compared with the type-2 PLL which is based on PI control,the novel PLL achieves faster response and wider phase margin.Finally,verify the availability and the feasibility of the proposed method with simulation.The experiments shows that the novel PLL,compared with SRF-PLL which is based on PI control,achieves not only higher estimation accuracy,but also faster tracking speed and better filtering performance.Build the PMSM sensorless control Semi-physical simulation platform.The results of experiments confirm the superiority of the improved PLL in PMSM rotor estimation.