Two-stage interleaved power conditioner for connecting a 5 kW el. SOFC with a 750 V dc link

A power conditioner with a high voltage gain for a combined heat and power generation system based on a solid oxide fuel cell is presented in this paper. The power conditioner consists of two dc-to-dc stages: an interleaved boost converter with minimized input current ripple and a series resonant converter. By analytic investigation, a pre-estimation of the converter´s efficiency is shown and a method for calculating the current ripple of multi-phase interleaved converters is presented. The analytic results are used for an optimized converter design of a 5 kW prototype. An efficiency of 94.6% at nominal operation is reached.