A Piezoelectric Energy-Harvesting System with Parallel-SSHI Rectifier and Integrated Maximum-Power-Point Tracking

A piezoelectric energy-harvesting system, including a parallel-synchronized-switch harvesting-on-inductor (SSHI) rectifier and integrated maximum-power-point tracking (MPPT), is presented. The perturb & observe (P&O) algorithm is adopted for the MPPT of the parallel-SSHI rectifier. Furthermore, an output power evaluation algorithm for the P&O MPPT is proposed and its detailed implementation in the full analog domain is analyzed. Fabricated in 130-nm CMOS, measurement results show the piezoelectric harvesting system achieves a 417% energy-extraction improvement for the rectifier and a maximum 97% tracking efficiency for the MPPT, which makes the system achieve high energy-extraction improvement and MPPT efficiency simultaneously.