A Photovoltaic and Thermal Energy Combining Harvesting Interface Circuit with MPPT and Single Inductor

Abstract

This paper proposed a photovoltaic and thermal energy combining harvesting interface circuit. The time-multiplexed operating of the power stage circuit can harvest thermal energy and photovoltaic energy simultaneously in a cycle, obtaining high efficiency and a smaller volume of the system. Combined with the open-circuit voltage algorithm, the interface circuit outputs energy at the maximum power point. The proposed interface circuit is implemented in a 0.18 µm standard CMOS process. The simulation results show that the conduction time of the thermal energy path occupies about 50% of the cycle and the conduction time of the photovoltaic energy path occupies about 5% of the cycle. The peak tracking efficiency of photovoltaic energy is 99.1 % and the peak tracking efficiency of thermal energy is 99%. The peak power conversion efficiency of the overall circuit is 89%.