Mathematical sizing and design analysis of permanent magnet vernier machine for contra‐rotating wind power applications

Abstract Over the years, wind energy technology has vividly made progress, as it is economical and cleaner against fossil‐fuel alternatives. With the rapid upsurge in turbine ratings up to the MW‐power generation level, an unceasing effort is crucial to increase the torque/power density and power factor of the wind‐powered machines. Amongst wind‐powered machines, the permanent magnet vernier machine (PMVM) is renowned for its high torque density. This paper discusses the detailed design flow of a novel contra‐rotating PMVM including sizing equation, geometric relationships, and FEA‐based electromagnetic performance analysis compared to the conventional PMVM. The proposed contra‐rotating PMVM is analysed with two different winding configurations that is, first with crossed‐toroidal and later with concentrated winding configuration, and a comprehensive comparative analysis is made between proposed and conventional PMVM topologies. The contra‐rotation of rotors provides more torque/power than the co‐rotation within the given machine's size. This comparative analysis provides noteworthy insights into the superior performance of the proposed contra‐rotating PMVM topologies regarding torque/power, power factor, and efficiency. A superior torque/power of value 538.23 Nm/1.6 kW is achieved in the case of the design with crossed‐toroidal winding configuration with an efficiency of 97.82% whereas, a high‐power factor of 0.98 with an efficiency of 91.36% is achieved in the case of the design with concentrated winding configuration.