Design and control for an intensity controllable uni-polar magnetic field supplying unit for magnetic refrigeration

Magnetic refrigeration (MR) is making use of magnetocaloric (MCE) effect to refrigerate with the advantages of high efficiency, low energy consumption, and being environmentally benign. In this paper, the design of a uni-polar controllable intensity of magnetic field supply unit is described and implemented to improve the adjusting capability of magnetic field, H, for generating the related effect of magnetic field that is applied and the removal in MR to cool down systems. The proposed magnetic field supply unit, taking the coils as loading, is composed of a full-bridge PWM control inverter circuit, a coupling transformer, and a rectifier; thereby the controllable DC current can be outputted to regulate the total magnetic field by the produced H based on the magnetic core with wound coils. Simulation results demonstrate the feasibility of the presented structure, and the experimental results show the effectiveness of the controllable H ranges from 0.667 Tesla to 1.07 Tesla as well.