Research On Sensorless Control System Of Pmsm Based On EKF

With its special advantages of small size,light weight,low price and high efficiency Permanent magnet synchronous motor(PMSM)occupies a very important position in AC adjustable-speed system.In the actual operation of the motor,no matter what algorithm is used,the exact location of the rotor and speed information should be informed,the general strategy is to install the mechanical position sensor.However,position sensor with high-performance and high-precision causes high cost.Meanwhile,the permanent magnet synchronous motor can not be utilized widely because of its much too strict requirements for using conditions.This thesis discusses a control method of position sensorless permanent magnet synchronous motor based on extended Kalman filter,and analyzes it in detail.First of all,based on analyzing PMSM numerial model,combination thetory of vector control with technology of space vector pulse width modulation(SVPWM),paper constructrs PMSM vector control system based on rotor flux orientation.A new method is used to design the parameters of the PI regulator,and the simulation is performed in the MATLAB environment of SIMULINK.The simulation results show that the control system designed by this method can get good performance.The system simulation model is built and the principle of SVPWM algorithm is demonstrated.Secondly,paper analyzes the basic principle of Kalman filter theory,focusing on the optimal estimation of state equation and the linearization of nonlinear system.The extended Kalman filter(EKF)algorithm is applied to the PMSM control system and the EKF equation of the permanent magnet synchronous motor in the two-phase stationary coordinate system is derived.In the MATLAB simulation environment of SIMULINK,the rotor position and speed change curve are analyzed.The results show that the control system designed by EKF algorithm has good performance of speed and position tracking.This paper analyzes the influence of load variation and covariance matrix coefficient variation on the performance of EKF control system,and gives the design rules of covariance matrix.Finally,the paper uses TMS320F28335 model DSP from company TI as the core of themotor control.The principle and realization method of the control system software and hardware structure and main function modules are designed.The control circuit and other auxiliary circuit of the control system are designed for hardware.As for the software part,the main program,interruption subroutine and software realization program of each part are written,and the system debugging is finished on the experimental platform.