Control of rotor torque and rotor electric power in a reluctance wound rotor brushless doubly fed machine

In this paper, decoupled control of rotor torque and rotor electric power in a reluctance wound rotor brushless doubly fed machine, (BDFM), is presented. The machine stator windings are fed from two separate voltage source inverters. The proposed control technique is applied to the inverters such that the BDFM is capable of producing mechanical torque at any desired synchronous speed and simultaneously delivers n-phase rotor electric power through the rotor terminals independent of the mechanical loading. This technique can eliminate the need for slip-rings and can be used in applications such as rotational antennas and turret systems. An existing slip-ring induction motor is modified to build up the proposed prototype BDFM. Simulation and experimental results validate the proposed control technique.