A new series of brushless and permanent magnetless synchronous machines

Abstract

This paper proposes a new series of brushless and permanent magnet-less synchronous machines. The main synchronous machine (SM) and the exciter machine are embedded in the same machine structure. Thus two different windings are put in the stator and rotor respectively. The exciter machine may be an induction or a synchronous machine but wound with different number of poles to have magnetic decoupling. Thus, these two machines can be independently controlled. However, the rotor winding (i.e. the field or excitation coils of the synchronous machine) is fed from the rotor windings of the exciter machine through a rotating rectifier. The rectifier converts the induced ac voltage/current to dc to feed the field of the SM. Depending on the type of exciter machine, two different types of machines result. This paper shows the performance of such machines. While details of performance in generating mode are considered, motoring operation is also possible. This paper shows some preliminary analytical and simulation results. Proposed machines have good potential and will definitely increase the use of synchronous machines in future.