Parameter Identification, Non-linearity, and Harmonic Effects in a Vernier Machine of the MAGNUS Type

This paper discusses the parameter identification of MAGNUS, a dual-stator Vernier-type axial-flux machine. MAGNUS machine can operate with the minimum number of stator slots at an extremely high polarity and is designed with a spoke-type permanent magnet rotor which is capable of achieving a very high flux concentration ratio. The direct and quadrature axis inductances are obtained through multiple methods, and it is shown that despite having the spoke-type rotor, MAGNUS has a non-salient behavior. The paper also examines the effects of non-linearity and very high content of mechanical harmonics on the operation of the machine through finite element analysis (FEA). Results from the experimental tests on the MAGNUS prototype are used for validation of the analytical calculations and the 3-D FEA results.