Torque Harmonics Minimization of Double-Stage Magnetic Gear Transmission System

An optimization study to reduce the harmonic components of the magnetic flux density due to the modulation effect in a coaxial Magnetic Gear Transmission system (MaGT) is presented in this paper. The results of the harmonic content analysis of a MaGT are used to optimize the design of a double-stage MaGT configuration for automotive applications presented in previous works. In particular, pole arc to pole pitch ratios of the two rotors and of the modulation ring have been tuned in order to reduce the harmonic content of the magnetic flux density. The comparison between two different case studies is presented in regard to core losses, maximum temperatures and overall MaGT efficiency. These analyses have been carried out by means of analytical formulations and finite element simulations using the FEMM software.