A microelectromechanical system (MEMS) piezoelectric energy harvesting device, a unimorph PZT cantilever with an integrated Si proof mass, was designed for low vibration frequency and high vibration amplitude environment. Pt/PZT/Pt/Ti/SiO 2 multilayered films were deposited on a Si substrate and then the cantilever was patterned and released by inductively coupled plasma reactive ion etching. The fabricated device, with a beam dimension of about 4.800 mm × 0.400 mm × 0.036 mm and an integrated Si mass dimension of about 1.360 mm × 0.940 mm × 0.456 mm produced 160 mV pk , 2.15 µW or 3272 µW cm −3 with an optimal resistive load of 6 k from 2g (g = 9.81 m s −2 ) acceleration at its resonant frequency of 461.15 Hz. This device was compared with other demonstrated MEMS power generators.

Piezoelectric materials (PZT) have shown the ability to convert mechanical forces into an electric field in response to the application of mechanical stresses or vice versa. This property of the materials has found extensive applications in a vast array of areas including sensors and actuators. The study presented in this paper targets the modeling of a PZT bender for voltage and power generation by transforming ambient vibrations into electrical energy. This device can potentially replace the battery that supplies the power in a microwatt range necessary for operating sensors and data transmission. One of the advantages is that it is maintenance-free over a long time span. The feasibility of this application has been repeatedly demonstrated in the literature, but a real demonstration of a working device is partially successful because of the various design parameters necessary for a construction of the PZT bender. According to a literature survey, the device can be modeled using various approaches. This paper focuses on the analytical approach based on Euler–Bernoulli beam theory and Timoshenko beam equations for the voltage and power generation, which is then compared with two previously described models in the literature: the electrical equivalent circuit and energy method. The three models are then implemented in a Matlab/Simulink/Simpower environment and simulated with an AC/DC power conversion circuit. The results of the simulation and the experiment have been compared and discussed.

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We analyzed the miniaturized energy harvesting devices (each volume within 0.3 cm 3 ) fabricated by using three types of piezoelectric materials such as lead zirconium titanate (PZT) ceramic, macro fiber composite (MFC) and poly(vinylidene fluoride) (PVDF) polymer to investigate the capability of converting mechanical vibration into electricity under larger vibration amplitudes or accelerations conditions (! 1g, gravitational acceleration). All prototypes based on a bimorph cantilever structure with a proof mass were aimed to operate at a vibration frequency of 100 Hz. PZT-based device was optimized and fabricated by considering the resonant frequency, the output power density, and the maximum operating acceleration or safety factor. PVDF-and MFC-prototypes were designed to have same resonant frequency as well as same volume of the piezoelectric materials as the PZT prototype. All three devices were measured to determine if they could generate enough power density to provide electric energy to power a wireless sensor or a microelectromechanical systems (MEMS) device without device failure.