A thermoelectric energy harvester with a single switch unified control for autonomous applications

Abstract

In the past decades, due to the increasing environmental concerns, many research works have targeted the use of energy harvesting technologies as an alternative to the fossil fuels. Free availability of heat makes harvesting energy from Thermoelectric Generators (TEGs) as one of the most viable sources of electricity. In a thermoelectric energy harvester, it is mandatory to perform Maximum Power Point Tracking (MPPT), aiming at maximizing the extracted energy irrespective of the temperature gradient conditions. The Open Circuit Voltage (OCV) MPPT method appears as the most widely used and suitable for TEGs. Moreover, the output voltage across the load must also be regulated. To perform MPPT and output voltage control simultaneously, conventional two-stage DC-DC converters are usually used. In this paper, we propose an unified control for a Single Switch DC-DC Converter (SSC), performing both, the MPPT and the output voltage control. Moreover, the reduction of the number of switches decreases the cost of the harvester as well as the size and the control complexity. The resulting harvester has been modeled and simulated; the results confirm the effectiveness and the robustness of the simultaneous MPPT and output voltage regulation.