An equivalent circuit model parameter extracting method for a piezoelectric bimorph

Abstract

An equivalent circuit model parameter extracting method for a piezoelectric bimorph includes such steps as fixing one end of piezoelectric bimorph on vibration source, freeing that other end, keepingconstant sinusoidal vibration acceleration amplitude a, sweeping frequency to obtain relationship curve between output voltage of piezoelectric generator and vibration frequency under different load resistances RL, and extracting parameters of equivalent circuit model of piezoelectric bimorph. The short-circuit resonant frequency fsc, open-circuit resonant frequency foc, static capacitance Cmc, mechanical quality factor Qoc, mechanical quality factor QML, maximum power value Popt, short-circuit resonant voltage VML (Omega sc) are determined. The equivalent inductance Lm, the equivalent capacitance Cm, the equivalent resistance Rm, the equivalent input stress VF, the piezoelectric coupling coefficient A and the static capacitance Cmc are obtained. The invention can accurately describe the relationship between the output voltage characteristic of the piezoelectric bimorph and the load, the ambient vibration frequency and the acceleration, and the electric measuring instrument required for measuring is low in cost.

Description

technical field [0001] The invention relates to the field of vibration environment energy collection technology and circuit design, more specifically, relates to a piezoelectric bimorph equivalent circuit model parameter extraction method. Background technique [0002] Vibration energy harvesting devices can convert the vibration energy widely present in the environment into electrical energy. The energy conversion methods are divided into three types: electrostatic, electromagnetic and piezoelectric according to the different electromechanical conversion principles. The electrostatic type is realized by the capacity change of the variable capacitor due to vibration. The most attractive feature of this method is that it has IC compatibility, and it can be manufactured by silicon micro-processing technology and mass-produced. But in order to realize voltage constraint or charge constraint across the capacitor, independent power supply support is required. Electromagnetics ge...

AI Technical Summary

Problems solved by technology

Some existing circuit parameter extraction methods rely on measuring the vibration state of the piezoelectric bimorph to calculate and determine the parameters, and the required measuring instruments such as Doppler laser vibrometers are expensive

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