关键词: 关断角控制, 晶闸管, 软启动器, 等效电路

Abstract:

For the three-phase ac regulation voltage circuit of soft starter with turn-off angle controlled type using thyristor,the circuit is equivalent to a reactance which changed with turn-off angle.In combination with asynchronous motor's simplified equivalent circuit model,an equivalent circuit of the soft-start main circuit is obtained.On this basis,this paper analyzes the relation between turn-off angle,stator current,electromagnetic torque,maximum electromagnetic torque,and critical slip ratio,with the conclusion that turn-off angle could effectively control starting current of the motor.The simulation results show that theoretical analysis is effective and feasible.

Key words: turn-off angle control;thyristor;soft starter;equivalent circuit