The Research Of Fuzzy Adaptive Soft Start Control On AC Asynchronous Motor

Motor starting directly has large current inpulse which would bring not only serious impact on electrifield wire neting,causing the quality drop of power supply, but also negative effect of the motor llife itself.In order to reduce the motor starting current and make equipment run steadily, soft starter arises at this time.Thyristor series connection voltage control soft start is contactless control mode and have perfect starting performance,low failure rate and can receive flexible start characteristics, comparing with the traditional"Y -Δ"and autotransformer start.Starting current and torque is the main indexes for evaluating the AC asynchronous motor soft startting performance,how to improve the two indeses and design high-performance control algorithm become a recent study hotpot in the field.The using of PID control algolithm is difficult to reach satisfactory control effectt for asynchronous motor soft starter system,which is time-varying systems system of not having accurate mathematical model.Fuzzy control is especially suitable for asynchronous motor soft starter complex system of nonlinear and strong coupling,which uses its own konwledge and experience and don't rely on the mathematical model of control system.Adaptive fuzzy control algorithm improves and optimizes the fuzzy control algorithm to improve the control performance of control system,which improves itself in parameter or rules during the control process.This paper make thyristor series connection soft start control system as the research object.Firstly.the technology research situation and development condition of motor soft start is introduced.Secondly, thyristor series connection soft start principle and soft start mode are analyzed;Thirdly,based on the principle of asynchronous motor start and nonlinear, time-variant properties,a kind of adaptive fuzzy contro algorithm has been designed.Finally,the sumulation and comparison has been made about the direct start and soft start system of PID control, fuzzy constant-current control and Torque fuzzy adaptive control,testing the torque fuzzy adaptive starting performance excellence.