engleski

Design considerations of the multi-resonant converter as a constant current source for electrolyser utilisation

An electrolyser is a current driven device, and the volume of produced hydrogen is proportional to the applied current density. To achieve optimal and efficient hydrogen production, it is necessary to calculate current to feed electrolyser and keep it constant despite the input voltage change, number of stacks, temperature, pressure or resistance change of each stack. A systematic design procedure of high frequency DC-DC multi -resonant converter as a constant current source optimized for interfacing electrolyser stack to DC voltage source is presented. The multi resonant converter can operate in four different modes of operation. Each mode of operation represents a specific four-stage sequence characterized by resonating specific part of multi element resonant network. The advantage of this type of converter is that all major parasitic reactances are included in resonant processes. The converter performs Zero Voltage Switching and Zero Current Switching on all switching components depending on the operation mode. The favourable switching conditions are not achievable throughout the whole operating range. The optimal switching region in DC conversion ratio characteristics is calculated and emphasized. The design presented in this paper is based on the mapping of the desired converter operating area in DC conversion ratio characteristic and the calculation of component values using parameters that derive from the selected operating area. The realized converter prototype operates in Mode I with high full load efficiency. The high partial load efficiency is maintained down to 50% of the full load. The realized converter maintains a constant output current with low switching frequency change. The zero voltage switching is achieved both for the power switches and rectifier diodes throughout the load range.

water electrolysis ; constant current ; resonant DC-DC converters ; load current characteristic ; zero voltage switching (ZVS)

nije evidentirano