A stator-flux-based vector control method for parallel-connected multiple induction motors fed by a single inverter

This paper presents a novel vector control method for a parallel-connected multiple motor drive system. The proposed control method is based on the stator-flux, and is capable of accurate and responsive torque control even if there are the rotor velocity differences among the motors. To confirm the validity of the proposed control method, the authors compare a simulation result of the proposed control method with that of the conventional V/f control method. The simulation results show that the proposed control method is effective for the step change in load torque, the rotor velocity differences among the motors and the rotor resistance variation. In addition, experiments on the acceleration and deceleration, and the step change in load torque using four test motors yield satisfactory results