Research On The Significant Technology Of Position Sensorless Control Of IPMSM

Nowadays,permanent magnet synchronous motor(PMSM)has been widely used in many application areas because of its advantages of simple structure,power density,fast dynamic response,etc;on this basis,interior PMSM(IPMSM)has higher efficiency and wider speed range,so it has higher research value.In order to overcome the difficult installment,higher cost,and lower reliability caused by traditional mechanical position sensor,this paper will make a deep research on the significant technology of sensorless control of IPMSM focusing on the stages of initial positon detection,low-speed openloop start-up,medium and high-speed stable operation.First of all,by analyzing the current response excited by rotating voltage,it is concluded that the current response contains the rotor initial position information under the rotor micro-movement state,so the method of initial position detection based on rotor micro-movement has been proposed.The amplitude of the injected voltage signal is determined by the change of current amplitude.This method is able to detect the motor initial position under different load situation and the results can always satisfy the startup condition,which proves its wide applicability.Secondly,in order to improve the stability of the system during openloop start-up stage,a damping loop based on instantaneous active power is used to compensate for load disturbances,which improves the anti-interference capability.The method of changing the amplitude of the given current by adjusting the instantaneous reactive power is adopted to accomplish the switching of the control strategy,which makes the switching process more smooth and reliable.Then,in view of the problems of traditional second-order sliding mode observer(SMO),a full-order SMO based on the extended back-EMF model has been studied,which improves the observation performance.The value range of sliding mode gain has been constrained by the conditions of accessibility and stability,so accurate observation results can be obtained at different speeds.Finally,on purpose of verifying the correctness and effectiveness of the proposed key technology of sensorless control,a simulation model has been built in the Matlab/Simulink environment for simulation verification,and an experimental platform has been built based on a 1k W IPMSM for experimental verification.The simulation and experimental results prove that the stability of sensorless operation of IPMSM can be effectively improved while the control strategy proposed in this paper is adopted.