Self-Powered Multiinput Hybrid Rectifier With Arbitrary Phase Difference and Low Start-Up Voltage for Piezoelectric Energy Harvesting

Harvesting vibration energy from multiple piezoelectric transducers (PZTs) can significantly enhance output power. However, prevailing methods either employ time-division multiplexing of the inductor to harvest energy or rely on complex external circuits to control switches, resulting in low energy conversion efficiency. A self-powered multi-input hybrid rectifier (SP-MIHR) with arbitrary phase difference and low start-up voltage is proposed in this article. There are both voltage bias flip and series synchronous switch harvesting on inductor (S-SSHI) operating modes, enabling energy harvesting from multiple PZTs with arbitrary phase difference using a single inductor. Experimental results show that the SP-MIHR circuit has a maximum end-to-end energy conversion efficiency of 67.3% and a maximum output power that is 1.47 times higher than that of the classical S-SSHI circuit, with a start-up voltage that is 0.5 V lower than that of the S-SSHI circuit. Compared with the multi-input standard energy harvesting circuit, the SP-MIHR circuit can achieve 4.12× power improvement and 1.3× voltage improvement with a simple structure and excellent scalability for multiple PZTs energy harvesting.

I. Introduction

With the continuous advancement of Internet of Things technology and wireless communication technology, wireless sensor networks (WSNs) have been widely employed in areas of society, including smart cities, environmental monitoring, telemedicine, and beyond [1]. However, the long-term operation of WSN nodes is limited by sustainable energy supply. Traditional methods utilizing batteries or wired power sources not only contribute to environmental pollution but also face limitations in terms of time and spatial scales. Hence, converting environmental energy into electrical energy to power WSN nodes has emerged as an effective solution to address this challenge [2].