A maximum power point tracking controller for thermoelectric generators

Thermoelectric generators (TEGs) directly convert heat energy into electricity for power-supplying sensors and other portable electronic devices. In this paper, a maximum power point tracking (MPPT) controller in the modified perturb and observe (P&O) algorithm was designed on the basis of analyzing the output characteristics of the TEG modules. The MPPT controller consists of a voltage sensor, a current sensor, a microcontroller and a SEPIC converter, which keeps the operating point of the thermoelectric generator tracking the maximum power point (MPP). The thermoelectric generator was heated to generate electricity, and a supercapacitor accumulated that energy. Experimental results using the MPPT controller present that the thermoelectric generator's output voltage achieves around 5 V, the output power achieves upward of 2W when the temperature difference ΔT=75°C and the operating point of the thermoelectric generator accurately tracks the MPP with a tracking efficiency of 99.8%; the charging power can be improved 89.65%.