Investigation of the gear ratio number impact on the cogging-torque of concentric magnetic gears with surface-inset permanent-magnets using an analytical model

This paper investigates the impact that gear ratio has on the cogging-torque signal of concentric magnetic gears with surface-inset permanent-magnets. Initially, a generalized 2-dimensional analytical solution for the magnetic field distribution is derived, and later on the electromagnetic and cogging-torque distributions are calculated using the magnetic flux density components under different conditions. The magnetization distribution pattern used for this analysis is parallel. The analytical model is used to generate quick results with the purpose to investigate the effect of the gear ratio number on the cogging-torque amplitude of each rotor. The results showed that magnetic gears with surface-inset magnets have low torque ripple for certain gear ratios.