Analysis on a Novel Flux Adjustable Permanent Magnet Eddy Current Coupler with a Double-layer Permanent Magnet Rotor.

Permanent magnet coupler (PMC) acts as a magnetic transmission device, the motivation and torque are transmitted through the interaction between the conductor rotor (CR) and permanent magnet rotor (PMR), the mechanical contact between the motor and load is eliminated. And for the effective suppression of the vibration, high reliability and efficient operation, it has been applied in electric power, petrochemical industry, pumps, blowers, water treatment and other fields [1]–[3]. Many structures of the PMCs had been designed, considering the rotational couplers, configurations as radial and axial magnetic flux represent two possible solutions [4]. For the typical axial flux coupler (i.e., disk type) and radial flux coupler (i.e., cylindrical type), the produced torque was controlled by adjusting the length of air gap or the coupling area between the CR and PMR [5]. However, the magnetic field utilization is lower for disk type, and additional mechanical devices are also needed to adjust the axial relative position between the CR and PMR for both types, the reliability is reduced and the space volume is increased. In [6], a flux adjustable PMC with a movable stator ring, whose slip speed can be adjusted by shifting the movable stator ring along the axial direction, was proposed, and the complicated mechanical devices can be avoided. In this paper, a novel flux adjustable PMC with a double-layer PMR is presented. The magnetic flux is adjusted by circumferentially controlling the relative position of the PMR’s two layers, the axial movement is replaced.