An Adjustable Electromagnetic Reducer with Three-Phase Stator Winding

Abstract

A magnetic reducer with a three-phase stator winding supplied by a static frequency converter with sinusoidal current, which is in phase or opposite phase with the EMF of the no-load winding, will have in this mode the maximum values of the electromagnetic moments of the shafts, proportional to the stator current. Rotors of such a reducer will not “stall” as long as the frequency converter is able to increase its current with the load increase. The electromagnetic moments of the rotors of the magnetic reducer exist due to the presence of the electromagnetic moment of the stator. The electromagnetic moments of the rotors are rigidly bound with the electromagnetic moment of the stator through constant coefficients. In a magnetic reducer with a frequency converter, all three electromagnetic moments are directly proportional to the active current of the stator winding. In the absence of active current in the stator, the electromagnetic moments of the stator and rotors are zero. In such a reducer, the electric channel can work in the motor and generator modes and convey the properties of a synchronous compensator to the reducer. A mathematical model of a magnetic reducer with a three-phase stator winding focused on the functional mode of a wind farm is proposed: the slow-speed shaft takes the external torque from the wind wheel, and the high-speed shaft transfers the torque to the generator. The model contains four equations of state.