An `electrolyser' is a cell which breaks water down into hydrogen and oxygen gasses by passing an electric current through the water. A dc-to-dc converter is needed to couple the system bus to the electrolyser. In this paper a fixed frequency, integrated boost-dual half-bridge LCL series resonant converter (SRC) with capacitive output filter is proposed for this application. In this converter, individual resonant converter modules operate with fixed frequency, fixed duty-cycle. The phase-shift between the resonant converter modules creates a potential difference across the primary winding of the boost transformer and thus induces voltage in the secondary winding which adds with the input voltage and thus boosts the input voltage to Vbus, depending upon the voltage required to regulate the output voltage of the converter. A systematic design procedure is given followed by detailed PSIM simulation and loss calculations for the designed 2.4 kW converter cell to show the performance of the proposed converter configuration.