An Asynchronous Motor Soft-Starter with Discrete Variable Frequency Technology

This paper analysis the control principle of the asynchronous motor soft-start with discrete variable frequency technology. A simulation model for the asynchronous motor soft-starter using discrete variable frequency technology is built based on MATLAB SEMUUNK/POWER SYSTEM. In start process, positive sequence sub - frequency such as 13, 10, 7, 4 discrete variable frequency is used in the soft-starter to simplified power circuit and its control. While on the power frequency time slice,a single neuron PID algorithm is used to limit the current. The simulation results verify the asynchronous motor soft-starter with discrete variable frequency technology not only reduces the initial firing current but also has bigger start torque, which has a faster start speed compared with the normal soft starter with current limit starting control technology.