Search

In this paper, the electromagnetic interference reduction effect of a magnetorheological (MR) fluid-gap inductor in a dc/dc converter is investigated. For a realistic electromagnetic simulation, a prototype MR fluid-gap inductor is built and put in a typical buck converter setup, and the current waveform of the inductor is measured. Based on the measured current waveform, a 3-D time domain finite element electromagnetic analysis is performed considering non-linearity of an MR fluid and complex geometry of the winding. The rms and maximum values of the leakage flux and eddy current losses of the MR fluid-gap inductor are calculated and compared with those of the air-gap inductor. It is predicted that the eddy current heat source due to the leakage flux from the gap is reduced by as much as 75.6% for the MR fluid-gap inductor. To verify the simulation data, the leakage fluxes of both MR fluid-gap and air-gap types of inductors are measured in a dc/dc converter setup, and their experimental results are compared with calculated ones. [ABSTRACT FROM PUBLISHER]

This paper proposes a new variable inductor for efficient power conversion which consists of the ferrite core and the gap filled with a magnetorheological fluid. Its main feature is to show a large inductance variation versus inductor currents even with a simple inductor structure and so it leads to improving light and intermediate load efficiency of power conversion systems compared with the conventional inductor with an air gap. To predict the characteristics of the variable inductor, the nonlinear magnetic permeability of the magnetorheological fluid used is accurately measured because the inductance value strongly depends on the magnetic nonlinearity of the fluid. With the obtained B-H curve, a 1 kVA variable inductor is designed and analyzed with three-dimensional finite element method taking into account the losses of the core and the fluid. Finally, to prove the feasibility and usefulness of the proposed inductor, a prototype inductor is fabricated and its experimental results are compared with numerical ones. [ABSTRACT FROM PUBLISHER]