Sensorless control on a dual-fed flux modulated electric motor

This paper proposes the operation principle and a new flux estimation method for sensorless control strategy for the dual-fed flux modulated electric motor (DFFM). The DFFM is designed based on the flux modulation theory, it includes two stator windings and one rotor which simplify the mechanical structure. The rotor has only modulation iron and no permanent magnets on it, so there is no cogging torque problem in this motor. With adjustment of the outer and inner stator flux rotating frequency and amplitude, different rotation speed and torque of the sandwiched rotor can be gained for the DFFM. Furthermore, an improved flux estimation based sensorless control strategy is performed on the proposed machine to fit the two winding set control situation. The startup and performance of the proposed control strategy is verified by the simulation and experiments.