Research On The Robust Adaptive Maximum Power Point Tracking Control For Variable-speed Wind Energy Conversion System

With the environment issues and energy crisis becoming more serious these days,it is high time to seek sustainable energies to replace the conventional ones.So far,wind energy has become one of the most promising and popular renewable energies due to its abundant energy resources and technical maturity.For a wind energy conversion system(WECS),in order to increase its annual energy yield,maximum power point tracking control(MPPT)is always needed.However,on the one hand,because a WECS is a highly nonlinear system with parameter uncertainties and disturbances,the conventional linear controls are unable to handle such issues;on the other hand,although there are lots of existing nonlinear control strategies available for WECS to solve the problems related to parameter uncertainties and disturbances,the tracking speed can hardly be guaranteed.In this event,new nonlinear method that can handle these two problems at the same time is still needed.In this paper,efforts are made to solve the control problems related to MPPT control of WECS.The researches include:(1)The system structure has been selected based on the review of the current structures.The research goal are settled according to the result of a systematic review of the state-of-the-art MPPT technologies.(2)Model of a direct-drive WECS based on permanent magnet synchronous generator(PMSG)has been established.A robust adaptive control method has been designed and applied to the WECS to handle the issue related to parameter uncertainties and disturbances.(3)Based on the conventional Prescribed Performance Bounded(PPB)adaptive control method,a modified robust adaptive control strategy has been deduced and implemented to the WECS.With this method,the MPPT performance can be guaranteed.The purpose of designing MPPT speed according to real need is then achieved.(4)A simulation model of a 10 kW WECS based on PMSG is established in Matlab/Simulink.The effectiveness and validity of the two methods,namely robust adaptive control and modified robust adaptive control with guaranteed MPPT performance,has been verified through simulations.(5)The novelty and shortcomings of this paper are summarized.Based on the shortcomings,possible future works,which may improve the current methods,have been stated.