Wide Speed Range Sensorless Control Of Surface Permanent Magnet Synchronous Motor

Permanent Magnet Synchronous Motor is widely used in servo systems with the advantages of high power density and high efficiency. Position and speed information of rotor is key to the implementation of PMSM's vector control, which is usually collected by mechanical position sensor. However, the sensors not only increase the cost and complexity of the system, but also limits the some applications of PMSM, such as high temperature, and high corrosion. In order to solve this problem, the sensorless control of PSMS has emerged and become the research hot spot.A brief introduction of PMSM and its control strategy is firstly presented, during which the sensorless control methods was put emphasis on.Then, the mathematical model of PMSM and the principle of vector control are analyzed. Based on the analysis and comparison of three vector control strategies, the strategy of id= 0 is adopted. In addition, the simulation model is established to demonstrate the validity of PMSM's vector control strategy.In addition, the wide speed range sensorless control strategy of SPMSM is proposed. In low speed range, the High Frequency Signal Injection Method is adopted. With the speed increasing, the Back EMF based on PLL is used to detect the position information of PMSM. The combination of these two methods requires a shifting strategy to transfer from low speed method to high speed range. In this paper, a novel combination strategy is proposed. In addition, the choosing method of threshold value is discussed based on the analysis of the High Frequency Signal Injection Method's estimation error. Simulation models are constructed and the simulation results demonstrate the validity of proposed scheme.Finally, the hardware platform and the software system of the PMSM control system is introduced. The experimental researches are carried out, including vector control with position sensor, High Frequency Signal Injection Method and wide-speed range sensorless control method. The experimental results indicate that the proposed method could quickly and accurately estimate the rotor position to ensure the wide-speed range sensorless control of SPMSM, and verify the feasibility of the strategy.