A Study Of PMSM System Key Issues Based On High Order Sliding Mode Methods

Permanent-magnet synchronous motor(PMSM)has been widely used in various aspects of the national economy due to its superior performance.How to improve the motor control performance,reduce the cost of control of the motor and solving the application problem in some certain circumstances has been the key issues in the field of motor control research.Combining with high order sliding mode technology,this paper studies the above problems from two aspects about sensorless technology and inverter harmonic restraining technology.As far the low precision problem of traditional sliding mode observer,a high-order terminal sliding mode observer is proposed in this paper.This method uses the high order sliding mode technique to suppress the sliding mode chattering phenomenon.The output of the observer can be used directly to calculate the rotor position,which avoids the phase lag problem caused by the low-pass filter through the traditional sliding mode observer.Simulation show,the designed observer can obtain satisfactory observation performance.In the PMSM control system,the present of inverter nonlinearities such as dead-time effect and turn-on drop result in distortion of stator current vector,and generate large harmonic current,seriously influence the dynamic performance of motor.To solve this problem,a harmonic suppression method based on generalized notch filter is proposed in this paper,the selective harmonic components of stator current can be eliminated through notch,as such,the adverse effect of control system because of inverter nonlinearities can be eliminated.On this basis,in order to solve the periodic disturbance problem in current loop of PMSM system,a controller based on high-order sliding mode technique is proposed in this paper.This controller have high robustness about the current disturbance,and can effectively weaken the high-frequency chattering signal introduced by the discontinuous controlling caused by traditional sliding mode.Simulation show the designed notch can effectively reduce the total amount of internal harmonics of the motor control system,and obviously improve the sine degrees of the current waveform;the designed controller can effectively improve the anti-disturbance performance of PMSM system.