Vibration model and frequency characteristics of the piezoelectric transducer in airflow-induced acoustic generator

Abstract

Piezoelectric transducers, which convert airflow induced vibrational energy into electrical energy, can be applied to self-powered supply and auxiliary power supply for various aircraft electronic systems. Micro-ringtone airflow piezoelectric generator, designed by the principle of airflow induced acoustic, is one kind among them. The vibrating piezoelectric generator, is usually mounted on the aircraft during the flight. The incoming airflow produces hydrodynamic acoustic source, which is the vibration source of the piezoelectric generator, actively vibrates the piezoelectric plate to convert energy. According to the vibration theory, a one-dimensional vibration model of piezoelectric generator with fixed peripheral pressure, under hydrodynamic excitation is established. The vibration and frequency characteristics of the piezoelectric transducers are analyzed by measuring the sound pressure and the piezoelectric generator voltage. Theoretical analysis and experimental results show that the frequency of hydrodynamic acoustic source is slightly lower than that of piezoelectric generator’s natural frequency. Maximum output power is obtained when the inflow speed is in the range of 128 m/s-148 m/s, the corresponding hydrodynamic acoustic source frequency is 6.9 %-8.7 % lower than the natural frequency of the piezoelectric generator. Excitation force Fex and the displacements of piezoelectric plate are in same frequency. But Fex is ahead of phase angle Ψ than the displacement of piezoelectric plate.