A Switched Capacitor Converter with Open Circuit Voltage MPPT Method for Piezoelectric Energy Harvesting

This paper presents a 7-phase switched capacitor converter with maximum power point tracking (MPPT) for piezoelectric energy harvester. The switched capacitor converter achieves the fractional open-circuit voltage MPPT method by reconstructing the capacitor array according to the appropriate voltage conversion ratio (VCR) to improve the mechanical energy harvesting efficiency in complex scenarios. The 7-phase switched capacitor converter designed in this paper can achieve voltage conversion ratios of 1/5, 1/3, 2/5, 1/2, 3/5, 2/3, and 4/5. Designed the switched capacitor converter in a 180 nm CMOS process. The simulation result shows when the vibration frequency changes, the overall efficiency of the proposed circuit can reach 80.66%.