Hysteresis controller based maximum power point tracking energy harvesting system for microbial fuel cells

Microbial fuel cell (MFC) is a new approach to accomplish simultaneous waste treatment and alternative energy production. An MFC employs exoelectrogenic bacteria to directly convert biodegradable substrates to electricity. The electricity production from MFCs can be maximized at a certain operating condition, which is defined as the maximum power point (MPP). However, it is difficult to maintain an MFC at its MPP during operation, because the power output from MFCs fluctuates constantly due to the changes of microbial activities or environmental conditions. This study developed a maximum power point tracking (MPPT) technique using digitally controlled potentiometers for hysteresis controller based energy harvesting system. Results with lab scale MFC reactors have shown that the system can track the MPP and maintain the maximum energy harvesting in real-time, suggesting that the proposed system can capture the most available energy from MFCs at the most efficient operating point.