Self-starting DC-DC converter for low-power and low-voltage microbial fuel cells

Abstract

Consulta en la Biblioteca ETSI Industriales (Riunet)

[EN] Microbial fuel cells (MFCs) take advantage of the metabolism of micro-organisms and utilize organic matter to generate electrical energy. They are interesting because they accept a wide range of organic matter as fuel. The most important applications include autonomous wastewater treatment, bio-batteries and biosensor. MFCs are low-voltage and very low-power devices that are influenced the kind of substrate and bacteria used. In this report, we develop a method to obtain electrical energy efficiently. The voltage at which energy is harvested from MFCs influences their operation and electrical performance. The output power is maximum for a certain voltage value. This noteworthy operating point is favorable in some applications where MFCs are used as a power supply. Getting energy at maximum power point is the main point of the report. It is possible with the correct energy processing circuit that permits regulate the MCF voltage with a feedback control. Within this project, an ultra-low power and fully-autonomous power management system dedicated to MFCs has been developed and optimized. It allows to guarantee the highest MFC performances independently of the power input and the output load conditions. In addition, this power management system allows to provide a conventional voltage level to the load. The first step has been the development of a resonant DC/DC converter which plays the role of startup circuit. This kind of circuit does not require a external energy source, even for low voltage and ultra-low power source conditions. Due to its low energy performances, this resonant converter will be used only during the start-up phase. The second step has been the development of a Flyback converter, which has the role of the main converter in the system. This converter is able to work with a stable MFC impedance, thus it obtains the maximum available power regardless the input and the output conditions. Finally, the converter provides an excellent performance even for low power and its output voltage archives the conventional level of the power electronics devices.