Research Of Intelligent Controller Of Soft Starter

Starting AC motor directly will produce large impact current which make significant increase harmonic of power gird.The increase in harmonic component. will shorten the life span of electrical equipment,increased the network energy loss and increased possibility of the occurrence of resonance on power system.Intelligent solid soft starter is based on the variable reactance technique,which is designed especially for large and medium electromotor in order to decline the maximum current during the starting.In order to reduce the influence and damage by the direct starting of 3-phase asynchronism motor,the soft start based on variable reactance technique is analyzed and the intelligent controller of this soft starter system is especially studied.In order to find a solution to reduce the influence and the damage of the motors, electrical load,power gird and electric equipments casused by impact current which is produced by starting three-phase asynchronous motor directly.We make a detailed analysis of the intellengent soft-start controller which is based on variable reactance technique.Also we describe the characteristics of the soft-starter.According to the requirements of the system of solid soft starter which is based on variable reactance technique,we discussed the construction and design of the intelligent soft-start controller.In order to adjust the voltage of variable reactor,thyristor power conversion unit is applied in soft starter.By changing the trigger angle of thyristor in secondary circuit of the variable reactor,we achieved adjustment of the stator voltage on motor. Intenligent solid soft start controller composed by DSP,man-machine conversation module,power supply circuit,communication line are analyzed and explored.Aslo we discussed the modular design method of the control software.In the end,the model of the soft start system is set up and simulated by Matlab/Simulink.The simulation and the experimental results shows that this soft starter can reduced the impact on power grid effectively.