Variable Flux Reluctance Generator: Analysis, Design and Comparison

This paper deals with the analysis of the potentials and limits of the Variable Flux Reluctance Generator (VFRG). This is a synchronous generator whose stator and rotor are salient. Two windings are addressed in the stator, the first one is supplied by a DC current and creates the excitation flux, the second one is a three-phase AC winding. The salient rotor modulates the flux so that an electro-motive force is induced in the three-phase winding. Some advantages of such a configuration are the robust rotor structure, which does not incorporate any permanent magnet or field winding, and the possibility to vary the induced electro-motive force by means of the current in the excitation DC winding. Therefore there is an increasing interest on such a VFRG. This paper deals with the analysis of the VFRG highlighting advantages and drawbacks. Some suggestions for a proper design are also discussed.