A Consequent Pole Single Rotor Single Stator Vernier Design to Effectively Improve Torque Density of an Industrial PM Drive

The vernier machine can utilize magnetic-gear effect, which conspicuously improves the torque production over other type of synchronous machines. However, a dual-rotor/dual-stator structure enabled high torque density vernier design is often unfavorable for industrial applications, due to manufacturing complexity and thermal management challenges. This paper successfully addresses this problem, by building magnetic-gear effect into a consequent pole enabled alternating flux barrier structure with single-rotor single-stator (SRSS). In this way, the proposed machine can achieve a superior torque density as a vernier machine does, while maintaining an equivalent manufacturing complexity as a conventional SRSS synchronous machine. This paper begins with elaborating generic analytical equations, that can transform into a vernier machine or a SRSS synchronous machine. More specifically, the magnetic-gear effect is manifested via stator teeth originating flux modulation concept and resulting multi-harmonic field coupling effects in the equations. A SRSS vernier topology with consequent pole and V-shape magnet is then proposed. A considerable 52.6% improvement on the torque production with comparable efficiency are validated by experiments, where the comparison is made over that of a benchmark rare earth PM machine. Power factor would fall behind with increasing current load. Overall, this new design achieves outstanding torque density, showing solid potential for industry adoption.