Adaptive sliding mode observer and loss minimization for sensorless field orientation control of induction machine.

摘要

Induction machines are widely used in industry application. Consequently more and more attention has been given to design and development of induction machine control. High performance of induction machine control is achieved by so called field orientation control (FOC). Speed sensorless technology has also been proposed for decades to overcome the disadvantages of cost and fragility of a mechanical speed sensor. However, due to the high order, multiple variables and nonlinearity of induction machine dynamics, the development of advanced induction machine control is still a challenging task.; In this research, a sliding mode based flux and speed estimation technique for speed sensorless control of field oriented induction machine is first investigated. The parameter sensitivity of the control method is also analyzed. A robust sliding mode speed controller is also presented, which has the advantage of disturbance rejection and avoiding re-tuning gains comparing to traditional PI controller.; Then an adaptive sliding mode observer is proposed and the stability is verified by Lyapunov theory. Two sliding mode current observers are utilized to compensate the effects of parameter variation on the rotor flux estimation, which make flux estimation more accurate and insensitive to parameter variation. The convergence of the estimated flux to actual rotor flux is proved by the Lyapunov stability theory.; Finally, an efficiency optimization method which does not require extra hardware and is insensitive to motor parameters is presented. The relationship between stator current minimization and motor loss minimization in the induction motor vector control system is investigated. A fuzzy logic based search method is simulated and implemented. It is determined that the motor loss minimization can be achieved by minimizing stator current in practice.; An experimental setup is presented in the appendix to verify the proposed approaches. The simulation and experimental results are presented to demonstrate the potential and practicality of the presented approaches.