Research On Position Sensorless Control Of Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection Method

The position sensorless control algorithm for a permanent magnet synchronous motor(PMSM)has been extensively studied,since it can eliminate the mechanical position sensor,which not only reduces the device cost and installation cost of the motor drive system,but also improves the mechanical robustness of the system.At present,the research on position sensorless control algorithm based on back electromotive force(back-EMF)is very mature and has been successfully applied to some general-purpose inverters.However,the algorithm based on back-EMF detection cannot be extended to zero-low speed zone.Therefore,it is of great significance to investigate the position sensorless control algorithm of PMSM in zero-low speed zone.In this thesis,an interior permanent magnet synchronous motor(IPMSM)is used to realize its position sensorless control based on a high frequency square wave voltage injection(HFSVI)algorithm.The main contents of this thesis are as follows:(1)The matrix form and the complex vector form are used to analyze the mathematical model of a PMSM respectively,and the transformation method among different coordinate systems are given.(2)The principle of PMSM field oriented control is briefly described.Then the parameter tunning methods of the current controller and the speed controller based on classical control theory are given.And the system bandwidth test method is presented.(3)The principle of HFSVI algorithm is given.The equivalence of the two demodulation methods is analyzed,and the steady-state performance and dynamic performance based on PLL and extended state observer are compared.(4)The principle of the initial position detection algorithm based on low frequency virtual position is given and the method of selecting the frequency and amplitude of the high frequency voltage signal is given.A modeling method of PMSM with inductance saturation effect is proposed and based on this,the simulation and experiment of the initial position detection algorithm are carried out.Finally,the effect of DC offset of the current sensor on the initial position detection algorithm is analyzed.(5)The principle of the hybrid seamless algorithm between the zero-low speed zone and the medium-high speed zone without position sensors is given.The mid-high speed zone adopts the sliding mode observer and the transition zone adopts a linear weighted switching algorithm.In order to ensure the stable operation of the transition zone,the position observer is designed to resist saturation and the motor acceleration and deceleration control is optimized.Finally the whole position sensorless control of the PMSM drive system is realized.(6)A PMSM test platform,including DSP-based hardware and CCS-based software,is constructed.The above algorithms are all verified by experiments.