Study On Intelligent Soft-Starter Of Ac Motor

To reduce the high starting current as asynchronous motors start up directly and eliminate the negative influence that brought about by switching of contact when it starts up with reduced-voltage means, A new method based on power electronics technology for improving the starting characteristics of 3-phase asynchronous motor is presented.The 3-phase regulating circuit of asynchronous motors system is analyzed and simulated in MATLAB. The simulation results present that the system based on the 3-phase regulating circuit can reduce the high starting current as asynchronous motors start up directly. Based on the 3-phase regulating circuit in MATLAB, an adaptive single neuron PID control algorithm is presented in this paper. This algorithm is simulated in the system built by MATLAB, and the simulation results show that this control algorithm is not only effective to limit the starting current, but also robust against parameters variation and load change.A soft-starter based on DSP is implemented in this paper. The soft-starter employs high performance microprocessor TMS320F240 DSP as control core and its synchronous circuit can endure strong electromagnetism interference and it has the intelligence to judge the phase order. It has two kinds of starting modes: the slope voltage starting, the limiting current starting. The experiment consequently prove that the soft-starter can reduce the current impact for motor starting. In the thesis, the analyzing and designing process of hardware and software in the system are given.