Strategy On Speed Sensor-less Control Of Permanent Magnet Synchronous Motor

In the high-performance AC regulating speed system consisting of permanent magnet synchronous motors,in order to accurately measure the rotor position and speed of the motor,the mechanical speed sensor is mounted on the rotor shaft,such as photoelectric encoder.The use of such mechanical sensors can bring about such as reducing system reliability,improving costs and other defects,so the control technology of speed sensor-less has been researched and developed.At present,there is no single speed sensor-less control method to achieve the motor in the full range of control,and most of the speed sensor-less control method is based on the salient pole permanent magnet synchronous motor research,the research on the surface mount permanent magnet synchronous motor is relatively small.In the thesis,the speed sensor-less control method of the permanent magnet synchronous motor in both low speed and high speed is used to compose of a compound control method to realize the control of the motor in full speed range,and the simulation verifies that the system can achieve smooth and effective switching in the speed transition interval.Firstly,the mathematic model of the permanent magnet synchronous motor is deduced.Based on the principle of space vector modulation,the corresponding motion equation of the motor in each coordinate system are established.Moreover,the vector control simulation model is set up,and the simulation results are analyzed.Then,a sensor-less speed control method to optimize the fluctuating high frequency voltage signal injection is proposed.The basic principle of the fluctuating high frequency voltage signal injection method for low speed running pulse is introduced.The mathematic model of each module in this control method is analyzed carefully and the current signal processing process is optimized,and the control method of the speed sensor-less is proposed for optimizing the fluctuating high frequency voltage signal injection,and the simulation model of the fluctuating high frequency voltage signal injection method before and after the optimization is constructed and compared.Furthermore,the simulation results show that the model reference adaptive system has good operation performance in high speed section.The basic principle of model reference adaptive control for high speed operation is introduced.The stability of the whole adaptive system is verified by Popov stability principle.A corresponding reference adaptive simulation model is established.By comparing with the method of the speed sensor control,it shows that model reference adaptive has good motor speed tracking performance in high speed section.Finally,according to the combination of the fluctuating high frequency method and model reference adaptive method,a composite speed sensor-less control method is proposed to realize the motor running in full speed range.The simulation model of compound control method is set up to verify that the switching process can smooth and effectively transit from low speed to high speed.