Design and control of a PM brushless hybrid generator for wind power application

In this paper, a new permanent magnet (PM) brushless hybrid machine is proposed and implemented for wind power generation. The originality is that a small de field winding and an extra air-bridge are incorporated in the machine so that the air-gap flux can be effectively strengthened or weakened to online keep the output voltage constant throughout the whole wind speed range. The characteristics of flux linkage and no-load electromotive force (EMF) are analyzed by using the finite element method (FEM), and these results agree well with those from magnetic circuit analysis. Experimental results also verify that the proposed machine can produce a constant output voltage over a wide wind speed range.