Research On Current Controller And Flux Observer Of Vector Control System For PMSM

Permanent magnet synchronous motor(PMSM)has been widely used in rail transit because its high efficiency and small volume compared to induction motor.It is of great significance to study the control of PMSM.The current regulators and the flux observers of PMSM are mainly studied separately in this paper.Transformation to the synchronous reference frame yields the speed-dependent cross-coupling term between d and q-axis in the voltage equation due to armature reaction.The traditional decoupling methods are studied in detail in this paper,including feed-forward decoupling,feedback decoupling,internal model decoupling and deviation decoupling.The performance of these decoupling systems is compared and analyzed through Pole-Zero map and Bode,and the influence of parameter estimation error,system delay and system time delay compensation on control performance is also considered.The state feedback decoupling with two degrees is designed to improve the decoupling effect on the basis of these traditional decoupling methods.Since the optimal structure of the state feedback decoupling can not be designed by the existing methods,this paper introduces the Dynamic Relative Gain Array(DRGA)into the decoupling analysis of different regulators and the decoupling performances are intuitively expressed.DRGA was introduced as a measure of interactions for multivariable,and has been mainly used in process engineering areas.The decoupling optimal structure of state feedback decoupling can be designed by DRGA,and the analysis was verified by simulation and experimental results.The flux observer is used to improve the torque control precision and reduce the risk of irreversible demagnetization.Two kinds of permanent magnet flux observers based on sliding mode and model reference adaptive are designed respectively.Both of them are compared and verified through simulation and experimental results.