Numerical simulation of DMFC-capacitor hybrid power supply system for small electronic devices

A simple numerical simulation of current flowing through electronic devices was examined for a hybrid power supply system composed of a DMFC and a capacitor connected in parallel. The simulation was investigated by representing a combination of ohmic resistance, charge transfer reaction resistance, mass transfer resistance and double layer capacitance of a DMFC as a simple ideal resistor, based on measured data when DMFC was generating electricity. The simulation result was found to agree with experimental measured current flowing through the DMFC and the capacitor, although a slight disagreement was observed because of the presence of ohmic resistance between circuit components. The simulation of DMFC-capacitor hybrid power supply system indicated the importance of the inner resistance of the capacitor. The hybrid simulation was also applied to a system assumed to consist of μDMFC and micro electrochemical capacitor (MECC) system. The effect of applying a DC-DC converter to the system was indicated. The simulation allows to predict the degree of improvement required without performing actual fabrication of μDMFC and MECC.