Circuit design for an impact-type piezoelectric system for micro-wind energy harvesting

In this paper, a power management circuit with sleep mode for impact-type piezoelectric micro-wind energy harvesting system was proposed. Based on the analysis of the output characteristics of impact-type piezoelectric energy harvester, a new resistive matching impedance strategy was proposed to obtain maximum power. Besides, a low-power oscillator was presented to realize sectionalized frequencies. Finally, experimental results show that the controller for sectionalized matching impedance consumes 9.9% of the harvested power when the input average power is 0.9mW, and only 3.7% when the input average power is 2.1mW. The efficiency of the proposed sectionalized matching impedance energy harvesting circuit is around 76 %, which is increased by 59% and 22% at the strike frequency of 0.5Hz, as compared with the constant resistive matching circuit and with the constant resistive matching circuit having sleep mode, respectively.