Influence of contact thermal resistances on the Open Circuit Voltage MPPT method for Thermoelectric Generators

The thermoelectric effect has been appeared as an alternative source for electrical power generation. It has been used in Thermoelectric Generators (TEGs) to supply electronic circuits with the recovered thermal energy dissipated in an environment. A TEG is a device formed by the association of semiconductors that convert heat into electrical energy proportional to the temperature difference across it. In a simplified approach, a TEG can be modeled by a constant DC voltage source in series with its internal resistance; however, in a more accurate model, real internal contact thermal resistances must be considered. Maximum Power Point Tracking (MPPT) algorithms are used to extract the maximum power from a TEG during its operation. In the literature, the MPPT method relying on the Open-Circuit Voltage (OCV) is the most widely used and suitable for TEGs. The aim of the present paper is to evaluate the influence of contact thermal resistances on the OCV method used for the MPPT. Simulation results show that the OCV method tracks efficiently the maximum power point even when the contact thermal resistances in the TEG model, under constant temperature gradient conditions, are considered.