A Simple Method for Performance Prediction of Permanent Magnet Eddy Current Couplings Using a New Magnetic Equivalent Circuit Model

TLDR

The paper discusses the limitations of the proposed approach and investigates the underlying reasons. The study presents a simple magnetic equivalent circuit technique to calculate performance parameters of permanent magnet eddy current couplings. The MEC model uses lumped parameters and a branch magnetic circuit to account for eddy currents, deriving a complete formulation for the reaction (leakage) flux. Verification shows the method’s torque predictions agree closely with 3D FEM and experimental data over a wide slip‑speed range, and it performs well in simulating couplings with varied design parameters.

Abstract

A simple and practical magnetic equivalent circuit (MEC) based analytical technique for calculating the performance parameters of the permanent magnet (PM) eddy current coupling is presented. In the proposed MEC model built with the lumped parameters, the eddy current effects are inherently taken into account by introducing a branch magnetic circuit allowing for the magnetomotive force and the reaction magnetic flux. A complete formulation for the reaction flux which is treated as a kind of leakage flux is derived. A verification process is conducted and it is shown that in a considerably wide range of slip speeds, the torques predicted by the presented method match well with those obtained by both the three-dimensional finite element analysis and experimental measurement. The new MEC-based method also proves to be effective in the performance simulation of the PM eddy current coupling with different design parameters. In addition, the limitation of the proposed approach is also discussed and the reasons are fully investigated.