Design and Analysis of Electromagnetic Gears With Variable Gear Ratios

In this paper, the electromagnetic gear (EMG) with variable gear ratios has been proposed. With proper excitation of dc field windings, various pole pairs or gear ratios can be obtained, while its transmitting torque can be also adjusted in response to different applications. Hence, the proposed EMG takes definite advantage over the recently developed magnetic variable gear in terms of gear-changing controllability and torque capability. Meanwhile, with the field-modulated topology, the proposed EMG enjoys the merit of overloading protection compared with the conventional mechanical variable gear. Both steady-state and transient performances are simulated, which well verifies the validity of the proposed EMG.