Design and Evaluation of PM Vernier Machine for Urban Air Mobility Propulsion Applications

초록

For aircraft propulsion motors, the torque and power density requirements are highly demanding and beyond what is currently achievable. This article intends to thoroughly examine the feasibility of a surface PM vernier machine (SPMVM) for electrical vertical takeoff and landing (eVTOL) applications, where very high specific torque (torque per mass) is required. It was shown that, in contrast to conventional PM machines, the performance of SPMVM is quite sensitive to certain design parameters, including stator slot geometry and PM dimensions. The implications of various design characteristics of SPMVM are discussed, which ultimately guides the necessary design philosophy in order to attain higher specific torque levels as well as improved power factor. The achievable specific torque, efficiency, and power factor were also shown to vary with the choice of the slot-pole combination. Following the outlined design guidelines, two DD SPMVMs featuring distinct slot-pole combinations have been designed, together with a conventional PM machine serving as a reference model, all rated at 204 kW at 1300 r/min. A comprehensive comparison of the electromagnetic performance between the designed SPMVMs and the reference model is presented. The designed SPMVMs can attain a specific torque of approximately 50 Nm/kg, nearly double the specific torque obtainable from a conventional PM machine. To further assess the feasibility of the designed SPMVMs, a thermal analysis of the designed machines is also conducted.

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