Design and Analysis of Double Voltage Self-Powered Synchronous Switch Interface Circuit for High Impedance Piezoelectric Energy Harvesting

Although the synchronized switch harvesting on inductor (SSHI) circuit can obtain eight times the energy of the standard energy harvesting (SEH) circuit at its optimal impedance, the energy collected is much lower than its optimal value due to the influence of the load at high impedance, and even less than the max collection power of SEH. This article devises a double-voltage self-powered synchronous switch interface (DSPSS) circuit for piezoelectric (PZT) energy harvesting, which combines a double-voltage circuit and SSHI technology. Double voltage technology is used to increase the energy output under high impedance. The SSHI technology is used to reverse the voltage of the PZT to decrease the energy waste generated by the natural inversion of the PZT voltage. Finally, it is verified by simulation and experiment that when the internal equivalent capacitance value of PZT in the DSPSS circuit is 490 nF and the vibration is the same, the DSPSS circuit can obtain nearly two times of the SEH output energy. The optimal load value of this circuit is close to eight times of the SEH circuit. When the vibration frequency is 50 Hz, the open circuit voltage of the DSPSS circuit can reach two times of the SEH circuit.