Research And Implementation Of Sensorless Vector Control For High Speed Permanent Magnet Synchronous Motor

In this paper,sensorless vector control of the surface mount high speed permanent magnet synchronous motor(HSPMSM)is comprehensively studied by theoretical analysis,simulation and experiment.Accurate observation of flux is important for high performance control of HSPMSM.In this paper,the flux correction is introduced into the conventional back EMF flux observe.That improves the observation accuracy of the motor flux.This paper focuses on a correction method of rotor positions based on the current error.Because the output of the d-axis current loop regulator is related to the error of rotor's positions with feedforward terms,the output is assigned to the error signal of the PI regulator to form a closed loop observation of the position error.Then the error is used to correct the estimated rotor position in real time.Compared with the conventional sensorless control method,the proposed method solves the problem of the error caused by sampling,data refreshing and so on,converges the error to zero,improves the accuracy of rotor position observation greatly,and enhances the anti-interference ability of the system.At the same time,the current of dq axis is offset from the given value and the current is effectively utilized.The method has important engineering application value for the high precision control of HSPMSM under the condition of sensorless.A kind of power droop I/fclosed-loop vector control strategy,based on open loop I/f vector control,is proposed in this paper at starting.Because variation of reference frequency is positively correlated with power variation,power variation can be assigned to the error signal of the P regulator to form a closed loop observation of reference frequency.In this method,power variation is obtained based on the power by high pass filtering.Compared with open loop I/f vector control,the proposed method raises the speed of convergence,enhances the anti-interference ability and solves motor faults at starting,such as speed fluctuation easily,easily out of motor'step when loading and unloading suddenly.In this paper,the method of current vector multi-directional injection is used to realize the initial position of the rotor,the method of weighting coefficient is used to correct the position of the rotor to ensure the smooth switching of the control process,and the dead time compensation strategy is adopted to reduce the system failure rate.Simulation and experiment results show that the proposed metheds can practicably improve observation accuracy of rotor position,improve motor starting performance,enhance the anti-interference ability of system,and have high practical value.