Electromechanical switching voltage converters with application to cold start for thermoelectric generators

Abstract

Abstract This work proposes a novel technique for the control of modern inductor-based switching voltage converters (SVC) (e.g., boost, or buck converter), which is inspired by an old self-oscillating mechanical converter topology. According to the proposed technique, a relay component replaces both the inductor and the semiconductor switch of the SVC. The magnetic coupling between the switch and the inductor eliminates the need for a separate oscillating control circuit, which is usually required for the operation of an SVC, leading to a very simple converter topology. The electromechanical SVC (EMSVC) is self-oscillating, operating automatically whenever sufficient power is applied at its input. In this work a boost converter EMSVC design, as well as a buck converter EMSVC design are presented. Additionally, a boost converter EMSVC implementation, optimized towards thermoelectric cold start applications, is presented with experimental results. The converter can operate with an input of only 25 mV and 6.5 mA, and if combined with a thermoelectric harvester, it can be used for heat energy harvesting from temperature difference as low as 1 °C.