Research On Sensorless Speed Control Methodes Of Permanent Magnet Synchronous Motor

With the enlarging range of the application of permanent magnet synchronous motor(PMSM),the limitation of mechanical speed sensor is becoming more and more obvious.Developing a sensorless control system with excellent performance has become one of the focuses in the field of AC drive.In this paper,three sensorless control algorithms,based on flux algebra calculus,model reference adaptive system and rotating high frequency voltage injection method,are researched.The mathematical principle of the method based on flux linkage algebra is expounded in this paper.The zero drift of integrator in the process of flux linkage calculation is discussed.In order to overcome this problem,a frequency adaptive negative feedback integrator is introduced.After the parameters are adjusted properly,the ideal integral effect can be achieved.At the same time,the correction algorithm for the direct compensation of zero drift error of integrator is discussed.In this paper,the mathematical model of the model reference adaptive system(MRAS)based on flux linkage is constructed for the salient pole PMSM under the control strategy of id=0.The correction of the model is proved based on the Popov super stability theory.Compared with the model reference adaptive method with current as the state variable,the algorithm with the flux linkage as the state variable has less computation.The mathematical model of PMSM under high frequency voltage is established.Salient pole tracking algorithm based on single synchronous rotating coordinate filter is discussed.The algorithm principle of rotor polarity discrimination based on magnetic saturation effect is expounded.The mathematical explanation of the error between the rotor position estimation and the truth in the process of motor acceleration is given,and the necessity of the slope function in the process of speed given is pointed out.In this paper,a salient pole tracking algorithm based on dual rotating coordinate system filter is proposed.This algorithm can better extract the positive sequence component in the high frequency response current,and further improve the rotor position and speed estimation accuracy.Based on the MATLAB/Simulink simulation platform,the simulation model based on flux linkage algebra method,model reference adaptive method and rotating high frequency injection method is built.Simulation verification is carried out for different working conditions.The experimental platform based on 7.5kW permanent magnet synchronous motor and NPC three level inverter is built.The platform uses DSP28335 as the core of the control circuit.The simulation and experimental results verify the correctness and effectiveness of the theoretical analysis.