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.