Load-Tolerant, High-Efficiency Self-Powered Energy Harvesting Scheme Using a Nonlinear Approach

Small-scale energy harvesting has become a particularly hot topic for replacing batteries in autonomous or nomad systems. In particular, vibration energy harvesting using piezoelectric elements has experienced a significant amount of research over the last decade as vibrations are widely available in many environments and as piezoelectric materials can be easily embedded. However, the energy scavenging abilities of such systems are still limited and are very sensitive to the connected load. The purpose of this paper is to expose a new approach based on synchronous switching on resistive load, which allows both a significant enhancement of the energy harvesting capabilities as well as a high tolerance to a change of the impedance of the connected system, especially in the low value region. It is theoretically and experimentally shown that such an approach permits increasing the energy harvesting abilities by a factor 4 compared to classical DC energy harvesting approach. Furthermore, the self-powering possibility and automatic load adaptation of the proposed method is experimentally discussed, showing the realistic viability of the technique.