Analysis on a Novel Flux Adjustable Permanent Magnet Coupler With a Double-Layer Permanent Magnet Rotor

This paper proposes a novel flux adjustable permanent magnet coupler (PMC) with a double-layer permanent magnet rotor (PMR). The PMR, as the only excited source, is divided into the inner and outer parts. The PMs in both parts are, respectively, staggered arrangement by N- and S-poles with tangentially magnetized direction. The inner part can be controlled to rotate to adjust the relative position with the outer part to offer a controllable excitation magnetic field. Therefore, the eddy current intensity and torque can also be adjustable. The structure and operation principle of the proposed PMC are illustrated in detail. Then, to analyze the field and torque at each different relative position of the two parts of PMRs, the change period of the relative position, from N-N (and S-S) to N-S state, is divided into seven steps. The distribution of magnetic field and air-gap flux density of each relative position is analyzed in static field, and the torque-speed curves are calculated in transient field by using the 2-D finite-element method. Finally, based on the torque-speed characteristics, the influences of the structural parameters on the torque are analyzed and calculated, which can provide a reference for structural optimization design of this kind of PMC.