Sensorless Vector Control Research And Simulation Of Permanent Magnet Synchronous Motor

The motion control of PMSM needs precise rotor magnetic pole position. Traditional method is using mechanical sensors to detect magnetic motor speed and location, but it has some problems such as: high cost, low reliability and poor adaptive capacity with adverse environment. Therefore, the research of a reliable, low-cost control method without mechanical sensors has become a hotspot in the field of motor control technology.Model Reference Adaptive System is a method based on fundamental excitation to estimate the rotor speed and position. It does well in usual and high speed control. The method based on fluctuating high frequency voltage signal injection is using the magnetic saturation of PMSM to estimate the rotor speed and position. It does well in low speed control.Based on the study of these two methods, the paper mainly completed the following works:An improved MRAS based on online rotor resistance identification is introduced. This model can estimate the rotor speed,position and resistance well, and it has good robust ability to adapt the change of rotor resistance. Basically, the estimation accuracy can satisfy the request of vector control system. It has good static and dynamic performance in usual and high speed control.Based on the improved MRAS and the vector control method which is based on id=0, a simplified MRAS is introduced. It has simple structure,small amount of calculation and good dynamic performance. The simulation results show the feasibility of the method. The simplified MRAS and the improved MRAS can be chosen with different request.To solve the limitation of MRAS in low speed control, the method based on fluctuating high frequency voltage signal injection is introduced which is particularly applicable to low speed control. By the weighted algorithm, these two methods are switched smoothly. This composite method is not only does well in low speed control but also in usual and high speed control. The simulation results show the feasibility of the composite method.