Wavelet fuzzy based self tuning controller for speed control of induction motor drives

Abstract

Threephase induction motors are the most widely used electrical newlinemotors in industrial applications due to their high reliability simple newlineconstruction relatively low cost and modest maintenance requirements newlineHowever for high dynamic performance industrial applications their control newlineremains a challenging problem because they exhibit significant nonlinearities newlineand many of the parameters mainly the rotor resistance and hence the rotor newlinetime constant vary with the operating conditions Field oriented control newlineFOC of induction motor drives is becoming a major candidate in high newlineperformance motion control applications Decoupling effect of torque and newlineflux dynamics leads to independent control of the torque and flux as in the newlinecase of a separately excited dc motor Though attractive FOC methods suffer newlinefrom disadvantages of sensitiveness to motor parameter variations such as the newlinerotor time constant and incorrect flux measurement newlineVariable speed issues of electrical drives are traditionally handled newlineby proportionalintegral PI and proportionalintegralderivative PID newlinecontrollers PI controller even though is simple has difficulty in dealing with newlinedynamic speed tracking parameter variations and load disturbances since the newlinecontrollers gain values are fixed The performance of the speed control newlinesystem also depends on the accuracy of the slip calculation Unfortunately newlinethe slip calculation depends on the rotor time constant which varies newlinecontinuously according to the operating conditions Thus the control newlineparameters of PI controller are not adaptive newlineIn the past two decades artificial intelligence techniques such as newlinefuzzy logic and neural network control have been applied for the speed newlinecontrol of electrical drives Fuzzy control provides a systematic way to newlineincorporate human experience and implement nonlinear algorithms newlinecharacterized by a series of linguistic statements into the controller newlinethe system is ill defined or too complex to have a mathematical newlinemodel the fuzzy controller provides an effective way to design the control newlinesystem newline newline