Analysis and comparison of two brushless DC generators with doubly salient structure and stator field winding

In this paper, comparison of 12/8-pole doubly salient electro-magnetic generator (DSEG) and 12/10-pole flux-switching electro-magnetic generator (FSEG) for dc generator application is performed. The configuration, operation principle and electromagnetic performance (i.e. field distribution, phase flux linkage, phase voltage, winding inductance and cogging torque) are comparatively studied with finite element analysis (FEA) based on simulation. Besides, the copper loss and iron loss are considered as the key features. The simulation results indicate that the FSEG has good sinusoidal and symmetric output voltage, hence the rectified output voltage ripple is smaller. Although the maximum output power of the FSEG is approaching to that of the DSEG, the field current of the DSEG is better utilized. The total losses and efficiencies of the two generators are very close, whereas the copper consumption of the FSEG is around 10% larger. With the merits of robustness and flexible control, both the FSEG and the DSEG can be a potential low-cost candidate for DC generation system.