A modular permanent magnet brushless generator for wind power

In this paper, a permanent magnet brushless machine for wind power with novel concentrated windings, is introduced, in which the special combination of stator slots/rotor poles is employed, resulting in high power density and low cogging torque. The distinct topology and operation principle are analyzed by using a 3-phase 24/22-pole prototyped machine as an example. Based on finite element method, the design aspects of the prototyped generator are presented. Finally, the experimental results from the prototyped machine, including electro-motive-force (EMF), electromagnetic torque, output power and efficiency validate the design. It shows that the open-circuit EMF waveforms are inherently sinusoidal with concentrated windings and without skewing of stator slots or rotor poles, and hence it exhibits significantly higher torque density and efficiency. The results lay a new choice for small wind power generation systems.