Active DC-Power Filters for Switched Reluctance Drives based on Dual- Active Bridge Converters

Switched reluctance machines receive increased attention by the automotive industry because of their cost efficiency. However, the independent phase excitation and the resulting current reversal demand a comparatively large dc-link capacitance to meet the requirements regarding the ripple on the dc-link voltage and current. A large dc-link capacitance increases the size, weight and cost of the machine inverter. The dc-link capacitance can be reduced by active filtering of the source current. Previously investigation showed, that a reduction of 80 % is possible. This paper proposes a galvanically isolated filter based on a dual-active bridge converter. All presented results are evaluated on a 20 kW switched reluctance generator for an automotive range-extender application.