A Permanent Magnet Synchronous Machine with Mechanically Controlled Excitation Flux

This paper presents the initial design of a permanent magnet synchronous machine with mechanically controlled excitation flux using the linear sliding motion of an additional excitation source placed inside a hollow shaft in the rotor. A new rotor design concept and assembling method are described and presented in detail. On the basis of 3D-FE analysis results, the principle of adjusting reluctance, magnetic flux distribution, flux linkage, field weakening rate, no-load back EMF waveforms, electromagnetic torque, magnetic tension, and the effectiveness of the excitation adjustment of the presented machine design are discussed. The presented machine concept enables the design of permanent magnet excited machines with a good flux control range operating in changing load conditions under variable rotor speed.