A Novel Self-Power SSHI Circuit for Piezoelectric Energy Harvester

Piezoelectric energy harvester (PEH) has been used to feed loads in military, health, animal tracking, and many other applications. A considerable amount of energy is dissipated in PEH to flip the output voltage through the internal capacitor and resistor of piezoelectric (PZT) material. One of the most effective techniques to harvest this power loss is called a synchronized switch harvesting on inductor (SSHI) technique. A parallel SSHI technique has been used to flip the terminal voltage of the PEH through external inductor. A new, simple, and effective circuit has been introduced in this paper for this purpose. The new circuit uses two capacitors only to detect the flipping points of terminal voltage replacing two resistors, eight diodes, and two capacitors in the state of the art circuit (SAC). The new proposed circuit (NPC) showed about 26% reduction in losses, 18% increased output power, and 10% increase in efficiency compared to the SAC in normal operating condition. Also, the NPC showed 38% improvement in output power compared to the SAC in different operating conditions. Besides these benefits, the NPC extends the vibration frequency operating range 10 times higher than the circuit without the SSHI and 2.5 times the SAC. The simulation and experimental results showed the superiority of the NPC.