Association of Flyback Converters to Harvest Energy from Multiple Hydraulically Connected Biofuel Cells

Biofuel cells use catalysts (chemical, enzymatic or microbial) to convert chemical energy from organic substrates into electrical energy. This paper investigates energy harvesting from several low-power biofuel cells to power a load under several volts. As biofuel cells can share the same fuel source, an isolation is required to aggregate energy towards high voltages (compared to a cell voltage). The proposed converter is based on the well known fly back topology. The efficiency of the fly back converter is about 60 % for an input power of 10 mW. The PCB area is 29 cm² compared to around 74 cm² for a previously built boost converter. The topology of the fly back converter includes a control circuit which allows a regulation of the input voltage to keep it around the maximum power point (MPP at around 0.3 V). This control circuit is powered internally through an auxiliary sub-circuit.