Adaptive Speed Tracking Control For Sensorless Permanent Magnet Synchronous Motor

Due to its small size, good reliability, high efficiency and good characteristics, permanent magnet synchronous motor has been widely used in a variety of high-performance requirements of the system. Under normal circumstances, mechanical sensors are used to drive permanent magnet synchronous motor on the motor speed and the position of the rotor poles detected. However, the presence of a mechanical sensor system could reduce the reliability of the system, make rotor system more complicated and increase the cost. It also limits the motor on special occasions. In order to overcome the lack of mechanical sensors, sensorless control has become one of the hot research field of motor control. The sensorless control means in the AC motor control system, without speed and position sensors, the use of variable substitution of the stator voltage or the stator current instead of position and speed estimation sensor system, are used to achieve the purpose of controlling the motor. In this thesis, in order to achieve the purpose of speed tracking control, an adaptive controller is designed for the sensorless permanent magnet synchronous motor. Adaptive control system is a structure which has the ability to adapt to the system. It could regulate itself automatically according to the environmental changes and the change of system parameters to maintain optimal or near-optimal working condition.This thesis first briefly describes the advantages, development status and the application of permanent magnet synchronous motor, permanent magnet synchronous motor control method are summarized, it also introduces the future trend of permanent magnet synchronous motor. And then we describe the structure and classification of permanent magnet synchronous motor, and focus on the mathematical model of the permanent magnet synchronous motor in the three-phase stationary coordinate system, two stationary coordinate systems and the mathematical model of two-phase rotating coordinate system, then we describe CLARKE transformation and PARK transformation of the rotor model between the coordinate systems. After the introduction of definitions, principles and research for sensorless control and adaptive control systems, according to actual model of the permanent magnet synchronous motor, assuming that only stator currents and voltages are available for feedback, a sixth-order nonlinear adaptive control algorithm is designed to achieve the propose of rotor speed tracking and rotor position closed-loop estimation, it is improved for the previously estimated rotor position of the open-loop structure. Finally, according to the adaptive controller designed before, simulation results of the motor system in the MATLAB environment prove that the adaptive controller has good control characteristics, and could be able to achieve the speed tracking. In the presence of interference, it still be able to achieve speed tracking which proves that the controller has good robustness.