We propose a new mechanism of electric power generation in which mechanical impact energy is transformed to electric energy by a piezoelectric transducer. To clarify the relationship between the input mechanical impact energy and the output electric energy in this method, we measured the electric output of a piezoelectric vibrator stimulated by an impact with a steel ball. An electrical equivalent model of the phenomenon is proposed to analyze the transformation efficiency as functions of the electromechanical coupling coefficient, the mechanical loss and the dielectric loss of the vibrator.

No abstract

This paper presents theoretical and experimental considerations of the energy storage characteristics of a piezoelectric generator developed previously by the authors. In this paper, the oscillating output voltage induced by mechanical impact via the piezoelectric effect is rectified, and the electrical energy is stored in a capacitor. The effect of the capacitance of the capacitor and the initial voltage is investigated using an equivalent circuit model. A maximum efficiency over 35% has been achieved with a prototype generator.

In this paper, the theoretical and experimental considerations on the high-power characteristics of a piezoelectric transducer are presented. First, we propose a new measurement method for the large vibration amplitude region using an electrical transient response to eliminate the effect of temperature rise. Then, a new loss mechanism concerning the piezoelectric effect is explained by observing the relationship between the vibration velocity and the current and their harmonics. A `piezoelectric loss' is newly introduced in the equivalent circuit model to describe the real loss phenomena clearly.