Topology Study And Optimal Design Of Magnetic Gears

Non-contact magnetic transmission devices offer advantages in terms of low vibration and noise,no lubrication demand,and long service life,resulting in vast prospects in industrial applications.Among the numerous devices,the magnetic gear based on magnetic field modulation has high torque density and inherent overload protection,and it has attracted great interests of researchers over the past decade.The study on new topology of magnetic gear is of great significance to improve its torque density,thus,making magnetic gear more sutiable in practical industrial fileds,especially for low-cost and high-reliability applications.This paper reviews the development and current research focus of magnetic gear at the beginning.Then,the field modulation principle of the conventional surface mounted magnetic gear is verified with the finite element analysis.The general design procedure is also summarized after multi parameter coupling simulation.The consequent-pole-type magnetic gear is proposed next.This new topology effectively improves the rotor mechanical strength and brings much convenience of installing the permanent magnets,and it also improves the torque density with an additional increase of reluctance torque.Furthermore,the analytical method of both magnetic gear topologies are deduced by dividing the magnetic gear into several sub-domains.In addition,a total of eleven topologies of magnetic gear are proposed by changing internal and/or external rotor structures and placing extra permanent magnets on the modulation ring.The performance variation of these topologies for different permanent magnet materials and size constraints are investigated,revealing the superiority of several typical structures.Finally,two magnetic gear prototypes are fabricated according to the previous optimization results.The good coherence between the test results of prototypes and simulation results verifies the validity of the new topology and its optimal design procedure as well.