Robust vibration invariant SSHI rectifier circuit for piezoelectric device

Abstract

Rectifier is the most critical block of the power conditioning circuit designed for the Piezoelectric Energy Harvester (PZEH). Maintaining high rectification efficiency under the variable ambient conditions is the major design challenge. This paper presents a novel topology of self tuned Synchronized Switch Harvesting on Inductor (SSHI) based rectifier circuit for PZEH which provides high power extraction efficiency over a wide range of frequency and magnitude of input vibrations available. The high rectification efficiency is maintained for different PZ devices also. The synchronization of SSHI block under different ambient conditions is achieved by an adaptively controlled pulse generator circuit which uses internal voltage sensing. An active diode circuit to reduce the conduction loss in SSHI block and forward voltage drop of rectifier is used. The proposed circuit is working from 100 to 350 Hz with flipping efficiency above 90% and power extraction efficiency around 50%. A maximum power conversion efficiency of 58 % and maximum flipping efficiency of 93.6% is obtained with a figure of merit of 467% and output power of 72:6 lW.