Speed Control of Doubly-Fed Induction Generator Based on a Improved Reaching Law Integral Sliding Mode Structure

As a nonlinear system with various uncertainties, doubly-fed induction generator(DFIG) is very sensitive to external disturbances and internal parameter variations. In order to suppress the external disturbances and system uncertainties and improve the dynamic quality of the motor speed control system, an improved integral sliding mode control is proposed, which based on a improved variable exponential reaching law. The reaching law introduces a variable speed reaching term on the basis of the conventional exponential reaching law and combines it with the integral sliding mode surface, which overcomes the shortcomings of the conventional exponential reaching law, improves the speed of the sliding mode reaching, and effectively suppresses the inherent chatter of the sliding mode control. The stability of the improved exponential reaching law is analyzed by Lyapunov function, and applied to the design of sliding mode controller for DFIG control system, and compared with some other classical methods to prove its effectiveness. The simulation results show that the designed sliding mode controller has better load disturbance resistance and robustness, effectively mitigating external disturbances and system uncertainties.