Research On Low Speed Sensorless Control Of Surface Mounted Permanent Magnet Synchronous Motor

With the development of power electronics and motor control technology, permanent magnet synchronous motor (PMSM) is widely used in the field of AC drive. In PMSM control system, the precise information of rotor position and speed is required. For this purpose, the mechanical sensor is installed. However, the additional sensor not only increases the cost and complexity of the system, but also reduces the reliability. In order to solve this problem, the sensorless control technology has emerged and become the research focus in the field of motor control.Low speed sensorless control technology is the key to achieve full speed range sensorless control, attracting widespread concern of scholars. Therefore, the principles and implementations of SPMSM low speed sensorless control are presented in this paper. Using the method of fluctuating high frequency voltage injection, rotor position estimation and sensorless control from stating to low speed running could be achieved.First of all, the mathematical model of PMSM and the principle of vector control are analyzed, while the id=0 strategy is adopted. The simulation results demonstrate the good performance of vector control system. Then, the principles of magnetic saturated saliency and fluctuating high frequency voltage injection are researched, while the implementations of initial rotor position estimation and low speed sensorless running are presented. The simulation results show that the proposed scheme is feasible. Additionally, the hardware platform based on the TMS320LF2407A DSP and PS21865 IPM is introduced, while the design processes of software are presented. Finally, the experimental researches aiming at a SPMSM which power is 800W are carried out, including motor starting and low speed sensorless running. The experimental results indicate that the rotor position could be estimated effectively and the sensorless control method is practical.