Electromagnetic field coupled circuits and open-loop control of fast starting processes in induction motors

To solve the problems of difficulty in speed measurement and low accuracy of speed measurement of induction motor (IM) during fast starting, the electromagnetic field coupling circuit (EFCC) and open-loop control of IM considering rapid speed change are proposed. First, the EFCC of IM is established through the stator circuit, air gap magnetic field circuit and rotor circuit, and the stator voltage and electromagnetic torque of the fast starting process are deduced from the air gap magnetic density on the basis of constant slip angular velocity, and then the open-loop control method based on the EFCC is given. Finally, compared with the open-loop control based on the TEC, the results of simulation and experiment show that the open-loop control based on the EFCC can follow the acceleration starting more quickly and the starting current is smaller, which is conducive to reducing the cost of the drive.