Research On The Intelligent Control System Of High Voltage Liquid Soft Starter

Motor soft starter has multi-function of starting motor,energy-saving and various protection. Motor starting current is large, and the impulse current can easily damage power grid and motor. Soft starter can effectively control starting current of motor, realize smooth motor starting, enhance utilization of power grid and extend the service life of motor.Based on consulting plenty of technological literature materials of domestic and overseas motor soft starter. By comparing characteristics of several methods of soft starter, and by comprehensive consideration of technology, reliability and economy, liquid soft starter is selected as the solution of motor soft starting. Through the analysis of principle of liquid soft starter, liquid soft starting system is constructed.This thesis designs a LPC2290 processor with embedded microcontroller as the core of hardware of liquid soft starting controller, including minimum controller hardware system, digital-to-analog and analog-to-digital circuit, switching input and output circuit, CAN bus communication circuit, I/O expansion circuit, buttons and light circuit, interface circuit of touch screen, Nand Flash storage circuit, power circuit. Based on the hardware circuit, software of liquid soft starting controller is designed with modularizing design method, the software flow of the module is described and the important parts of the program are given. As motor has the characteristic of nonlinear and time-varying when starting, control algorithm of liquid soft starting control is analyzed. Fuzzy control and PID control is combined with segmented control on liquid soft starting, which is based on advantages of both control, and the system has a good dynamic and static characteristics.Based on analysis of experimental data and problems solved in the experiment, It is verified that microprocessors embedded as control core of liquid soft starting control scheme is feasible. In the meanwhile, experiments results show that liquid soft starter with microprocessors embedded can effectively control motor starting current. The operation of control is convenient. The liquid soft starting system basically meets the requirements of motor soft starting performance.