Self-Oscillatory DC-DC Converter Circuits for Energy Harvesting in Extreme Environments

Abstract

A novel self-starting converter circuit technology is described for energy harvesting and powering wireless sensor nodes, constructed from silicon carbide devices and proprietary high temperature passives for deployment in hostile environments. After a brief review of the advantages using Silicon Carbide (SiC) over other semiconductors in extreme environments, the chapter will describe the advantages and principles when designing circuitry and architectures using SiC for power electronics. The practical results from a novel self-starting DC-DC converter are reported, which is designed to supply power to a WSN for deployment in high temperature environments. The converter operates in the boundary between continuous and discontinuous mode of operation and has a Voltage Conversion Ratio (VCR) of 3 at 300C. This topology is able to self-start and so requires no external control circuitry, making it ideal for energy harvesting applications, where the energy supply may be intermittent. Experimental results for the self-starting converter operating from room temperature up to 300C are presented. The converter output voltage, switching frequency, total power loss and efficiency were presented at temperatures up to 300°C.