Simple, fast and accurate maximum power point tracking converter for thermoelectric generators

Thermoelectric generators (TEGs) can harvest thermal energy producing electrical power from a temperature gradient. They are often employed in dynamic thermal environments, therefore it is important to quickly and precisely track the best operating point to maximize the power production. This paper presents an innovative way to measure the open-circuit TEG voltage without disconnecting the load, to be used in a Maximum Power Point Tracking (MPPT) algorithm based on the open-circuit voltage method. The proposed system is composed of a buck converter with embedded microcontroller, which is used both to compute the MPPT algorithm and to control the charging of a lead-acid battery. The prototype converter is tested using a TEG system and it can accurately set the optimum operating point almost instantaneously and without significant computational power requirements.