High frequency injection maximum power point tracking for thermoelectric generators

Thermoelectric generators (TEGs) can harvest thermal energy from waste heat sources to supply various power levels due to the Seebeck effect. The power generated by a TEG is dependent not only on the temperature difference across them but also on the electrical load applied. Typically, waste heat sources have variable operating conditions which means maximum power point tracking (MPPT) must be employed through the use of power converters to produce the desired operating point of the system and thus increase the system efficiency. This paper presents a new MPPT scheme which has not been previously applied to thermoelectric generators, the high frequency injection (HFI) scheme to achieve a fast and accurate tracking of the maximum power operation point for TEGs. The proposed MPPT scheme is implemented with a power converter, and the tracking scheme performance is experimentally evaluated on a commercial TEG module through three different experiments. The proposed scheme is also compared to the most commonly used MPPT scheme for TEGs, Perturb & Observe. The experimental results show that the tracking efficiency of the proposed MPPT scheme is 99.73% at steady-state compared to the ∼ 90% tracking efficiency achieved by the Perturb & Observe scheme, as well as a 3 times faster dynamic response compared to the fastest method recorded in literature.