Two-stage soft-switched converter for the electrolyser application

An ´electrolyser´ is part of a renewable energy system (RES), which breaks water down into hydrogen and oxygen gases by passing an electric current through water. A dc-to-dc converter is needed to couple the electrolyser to the system dc bus of the RES. This study proposes a two-stage soft-switched high-frequency transformer isolated dc-to-dc converter for this application. A zero-voltage transition boost converter is used as the front stage followed by an inductor-capacitor-inductor (LCL)-type series resonant converter (SRC) with a capacitive output filter. Since the boost converter maintains almost a constant bus voltage, the LCL SRC can operate with zero-voltage switching (ZVS) for the specified supply and load variations. A systematic design procedure is given followed by a detailed personal simulation program with integrated circuit emphasis (PSPICE) simulation and experimental results for the designed 2.4 kW converter cell to show the performance of the proposed converter configuration.