Evaluation, application and comparison of a double-rotor toothed toroidal winding wind generator over a wide power range

The double rotor, toothed, toroidal winding permanent magnet machine is not a well known concept and has received very limited attention in literature. In this study the concept is proposed for use as a direct-drive wind generator. The permanent magnet generator is optimised by means of finite element analysis over a wide range of wind power levels. For each power level the optimum design is compared with optimum non overlap winding and conventional overlap winding permanent magnet machine designs. Although the electromagnetic design of the generator is the main focus of the paper, some of the implementation issues are also discussed. An existing 15 kW double rotor permanent magnet wind generator is modified to include a toroidal winding, which is used as a case study. Both simulated results and practical measurements in the laboratory for the 15 kW case study toroidal winding PM generator are presented in the paper.