Sensorless Control of the Surface PMSM

The positions sensors not only increase the cost,but also degrades the performance and reliability of the drive system in some implements.A estimation method of position detecting based on back electromotive force(EMF)is proposed according to the sensorless control strategy of surface permanent-magnet synchronous motor(SPMSM)in this paper.First,the error angle of the rotor position is calculated by using back electromotive force which in the two-phase rotating frame and the feed-forward control.Then,the speed and the rotor position of SPMSM are estimated by the phase locked loop(PLL).Besides,the structure of PLL is improved in low-speed to keep the accuracy of the estimation and dynamic performance.The simulation model is built to verify the feasibility of the control method.Finally,the proposed method is complied on an experimental platform with a controlling chip STM32F103X(ARM).The results show that the approach has good performance in motor speed and rotor position estimation,The algorithm is simple,and of high precision of steady state and fast response.