Modeling and simulation of point-on-line switching of VSI-fed induction motor

A method of mathematical solution to simulate point-on-line switching of an induction motor after a brief moment of disconnection is presented. A comparative simulation study of an induction motor transient air-gap torque with delayed reclosing on to a sinusoidal and voltage source inverter (VSI), six-step, and pulse-width modulated (PWM) supplies for various delayed reclosing times is outlined. The three phases supplying the motor are simultaneously disconnected and are reconnected back to the motor simultaneously or in some sequence. The effect of such an operation on the transient air-gap torque is analyzed. The authors investigate simultaneous and sequential reclosing mechanisms of a motor to sinusoidal or VSI supplies to ameliorate switching transients