Development of a simplified hybrid ambient low frequency, low intensity vibration energy scavenger system

The design, fabrication, and characterization of a hybrid energy scavenger system, combining simultaneous piezoelectric and electrostatic energy conversion, is reported. A piezoelectric resonator beam (PZT) is integrated with an electrostatic scavenger whose variable capacitor (CVAR) doubles as the proof mass as shown in Fig. 1. This paper focuses on the piezoelectric component, which provides an inherent displacement feedback signal and a rectified 3.3 V DC rail with a 2.68 mW/cm³ power density to operate signal conditioning, and initial electrostatic charge control circuits. The system is mechanically robust with no change in operation after 30 million cycles at 2.5 m/s² of 120 Hz sinusoidal excitation.