Study Of Intelligent Soft Starter For Asynchronous Motor Based On Embedded

Huge impact current will appear when three-phase asynchronous motor starts directly, whichseriously affects the State Grid and motor performance. In order to solve this problem, at present, avariety of soft starters has appeared. Traditional asynchronous motor soft starter, whose structureand function are very single, most of which use series resistance, series reactance and so on. So,traditional soft starter has poor immunity, and control algorithm is very simple, complex andchangeable start current is not easy to control. For the above shortcomings, this paper designs anintelligent soft starter which uses32-bit high performance microprocessor LPC2378as core.The hardware modules of soft starter which this paper design include synchronization signaldetection circuit, signal processing circuit, voltage pulse trigger circuit, protection circuit, Ethernetcontrol circuit, LCD and key circuits, power circuits, etc. For the hardware immunity study: designswitch power and Linear power to supply the entire control system with power to make immunitygood, and output voltage ripple coefficient small. Thyristor trigger section use SCR-type coupler toprovides a pulse signal. Three-phase AC voltage, current zero-crossing detection circuit use high-speed optocoupler for capture, and multi-step timing circuit is used to process zero-crossing signalin order to reduce external electromagnetic interference signals.Soft starter software program use modular design, including main program module, signalacquisition and processing module, parameter setting module and data communication module. Allsoftware program modules are based on real-time multi-tasking preemptive μC/OS embeddedoperating system. Fuzzy adaptive PI control algorithm is used to control motor starting voltage,current. Build a small embedded WEB server and TFT color LCD, through PC web browser andLCD buttons to set the motor starting voltage, current, power, speed and other parameters.providing users with simple, clear human-machine interface to control motor soft start intelligently.By simulink software simulation, depth study fuzzy PI control algorithm to control motorstarting voltage, current, and on this basis, completed experimental study of intelligent soft starterwith32-bit high performance microprocessor LPC2378. Experimental results show that the softstart motor control system has good dynamic and static characteristics.