Research On Structure And Performance For Field Modulated Permanent Magnetic Gear

Compared to mechanical gear,many significant advantages are owned by magnetic gear according to the principle of magnetic coupling.Such as high reliability,reduced maintenance, overload protection by itself,non-contact input and output,low noise,small vibration etc.Because of lower torque density is delivered by conventional magnetic gear,high utilization,high torque density(up to 400) are provided by new FMPMG,so it can be compared with mechanical gear.In this paper, FMPMG is deeply studied.Based on special structure of FMPMG,detailed analysis and derivation for working principle are done by using analytical method,it’s considered that certain mathematical relationships must be meet between number of pole pairs of inner and outer rotor’s permanent magnet,magnetic blocks of modulator ring.Four operating modes of FMPMG are put forward,for operating mode of stationary modulator ring,rotated inner and outer rotor,torque and speed mathematical model are established between inner rotor,outer rotor and modulator ring.Based on the design requirements of FMPMG structure parameters,electromagnetic simulation models are designed and built by finite element software Ansoft,magnetic field cloud picture and magnetic field lines picture are got,harmonic picture is got by disintegrating inner and outer flux density in the air gap by fast fourier transform.Static torque characteristics,stable torque characteristics and magnetic field modulation mechanism of FMPMG are researched,static torque characteristics is summarized,the reasons for the torque ripple are analyzed in depth.and appropriate solutions are put forward,the established mathematical model is to be validated.Iron loss is main job losses of FMPMG,according to generating mechanism of iron loss,the distribution of inner and outer rotor yoke,inner permanent magnet and magnetic field in modulator ring with its variation is studied.Distribution of iron loss is summarized to provide a theoretical basis for efficiency calculation of FMPMG.The amount of iron loss at different speed is studied,iron loss and speed relationship are summarized,effective method of dividing permanent magnet block to reduce eddy current losses is raised.Based on mathematical model and solution method to FMPMG,mechanical properties is studied,the relationship between maximum output torque and transmission ratio,parameters of modulator ring,inner and outer air gap,thickness of yoke is analyzed.