A restart method is based on current injection for Induction Motor

Induction motor in the power failure, the inverter will block the pulse, the motor into the idling condition, after restoring the power supply, if the speed is unknown at this time, directly into operation will produce a lot of problems, so the detection of the initial speed is extremely important. In this paper, we propose to calculate the magnetic chain conductance under double closed-loop current injection based on the MRAS double closed-loop current injection initial speed estimation scheme, where the initial speed is obtained by calculating the q-axis magnetic chain conductance to be 0, avoiding the problem of possible errors in the frequency extraction process.