Mitigation of voltage regulation problem in flux reversal machine

Flux reversal machine (FRM) is a permanent magnet (PM) machine in which the magnets are on the stator, while the rotor consists of laminated steel. Therefore, this machine is simple in construction. Also, it is easier to remove the heat due to losses in PMs from this machine, as compared to conventional PM machines. Recent work on FRM used full pitch winding in lieu of concentric winding to increase its power density. EMF generated on no-load is about double when concentric winding is replaced by full pitch winding. However, this machine has very poor voltage regulation. Voltage on load falls to less than half of that on no-load. Therefore, it must be used along with auxiliary reactive power generating equipment. This reduces reliability and increases cost. In this paper, it is shown that flux switching machine (FSM), which shares the other attributes of FRM also has good voltage regulation characteristics. A machine, which has geometry similar to FSM, but with full pitch winding is proposed. The flux paths of this machine are similar to those of FRM. This machine has low voltage regulation. The generated emf is higher than that in FRM due to flux concentration. These claims are verified through detailed finite element based simulation study.