Reduced switch count double converter fed wound rotor induction machine drive for wind energy application

A reduced switch count double side converter fed wound rotor induction machine control for a wind energy application is proposed in this paper. The outputs of two converters are combined electromechanically in the machine and are capable of sharing the power equally both from stator and rotor simultaneously. In order to reduce the cost a new configuration using two half controlled converters for both the stator and rotor circuit is proposed. The proposed controller reduces the required kVA rating of both machine side converters, improves the efficiency and helps operating over a wide speed range. It is shown that the combined kVA rating of both the machine side converters are even less than that of the machine side converter for a conventional rotor side control configuration. Also, the proposed configuration is suitable for use with a rotary transformer since neither the stator nor the rotor winding will encounter zero frequency over the entire operating speed range. The proposed configuration is simulated for a 30 kW wound rotor machine in SABER and the simulation results are presented.