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 5V, the output power achieves upward of 2W when the temperature difference Delta T = 75 degrees 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%.