A bipolar self-start up boost converter for thermoelectric energy harvesting

Abstract

This paper proposes a transformer based self-starting boost converter for thermoelectric energy harvesting, which operates even when polarity inversion of thermoelectric generator (TEG) occurs. TEG is used to convert thermal energy into electrical energy. Due to the Seebeck effect, an open circuit voltage of the TEG is proportional to the number of thermocouples in series and to the temperature difference between cold and hot sides. A boost converter is needed when an output voltage of the TEG is low. Power converters generally need a control circuit. When initial energy in storage device is not enough, a start up circuit is needed. Start up circuits for TEG are generally designed for a unipolar input voltage. The proposed topology combines a boost converter with a cross-coupled CMOS rectifier which accepts polarity inversion of TEG, and includes a self-oscillating circuit for autonomous operation using a transformer. The circuit operation has been confirmed by simulation and circuit experiment.