Magneto-Thermal Analysis of an Axial-Flux Permanent-Magnet-Assisted Eddy-Current Brake at High-Temperature Working Conditions

Abstract

This paper proposes an analytic coupled magneto-thermal analysis of an axial-flux (AF) permanent-magnet-assisted (PMA) eddy-current brake (ECB) at high-temperature working conditions. In the topology investigated, permanent magnets (PMs) are placed into stator slot openings to increase the braking torque production capability. This modification enables to control the magnet flux by altering the DC excitation current. However, the utilization of PMs will make the construction vulnerable at high operating temperatures simply because the magnet properties and the brake capability are strongly dependent on temperature. Such problems require complex coupled multiphysics finite element analyses (FEA) to obtain the actual brake performance. The proposed approach offers a simple and effective solution that consists of magnetic and thermal models, which are coupled to each other in the time domain. The nonlinear electrical, magnetic and thermal properties are influenced by the temperature variation in time. An AF-PMA-ECB prototype is manufactured to validate the proposed coupled models and the experimental studies confirm that the proposed approach provides very practical results to determine the working conditions of the AF-PMA-ECB at high-temperature operations.