Design and Analysis of Contra-Rotating Permanent Magnet Vernier Machine

With the increasing trends in renewable energy technologies, wind energy is becoming a vital player in meeting renewable energy targets. This technology has vividly made progress, and over the years it is getting economical against fossil-fuel alternatives. As a result, wind-powered machines have gotten much attention, and with the rapid upsurge in turbine ratings beyond the 10 MW power generation level, an unceasing effort is crucial to increase the torque/power density of these machines. The permanent magnet vernier machines (PMVM) are very well-known high torque density wind-powered machines, this paper investigates the design and analysis of a PMVM with contra-rotating rotors to further improve the torque density of the machine. The contra-rotation provides more torque i.e. 532.61 Nm than conventional PMVM that provides 427.045 Nm torque, with less volume consumption. The toroidal windings used in the design have short end-winding lengths hence, making the overall design simple and compact. The proposed design is compared with the conventional design having the same structure except the rotors are rotating in the same direction and the windings used are distributed windings. The analysis shows a 24.72% improvement in the instantaneous torque of the proposed PMV machine. Further, the proposed PMVM has 96.5% efficiency whereas, in conventional PMVM it is 88.8%.