Theory and design of hybrid excitation permanent magnet synchronous generators

It is difficult to control the air gap magnetic flux of a permanent magnet synchronous generators, because the magnetic flux is determined by the property of permanent magnet and is approximately kept constant. In this paper, a novel hybrid excitation permanent magnet synchronous generator is presented, which takes the advantages of both electrically excitation and permanent magnet machines:1)it has no brushes; 2)the magnetic flux is easy to be controlled. The structure and operating principle are described. An example is given in the paper and the results are confirmed by experiments.