A General Equivalent Circuit Model for Piezoelectric Generators

Abstract

This article presents an equivalent circuit model for a piezoelectric generator which can include any number of vibrational modes. First the electromechanical equations are formulated using an assumed mode (for example, the Rayleigh-Ritz method), the mechanical equations are then decoupled by the standard eigenvector approach. A set of single degree of freedom equations are thus produced. The electromechanical coupling terms are modeled in the equivalent circuit using an ideal transformer, or a set of current-and voltage-dependent sources. To validate the equivalent circuit model, the results show excellent agreement with published analytical solutions for the first three vibration modes of a cantilever unimorph generator. The main advantage of the new method is that it can be used to simulate any circuit topology, for which there is no analytical solution, using a standard electronic simulation program. To demonstrate this, the analysis and design of a more complicated diode bridge circuit is presented.

Piezoelectric energy harvesting from vertical piezoelectric beams in the horizontal fluid flows

“…In this method the mesh vertices displacement,û, is computed by solving the Laplacian equation in the following form [43,44]: r ( rû) = 0; (16) where is the di usion coe cient. The boundary condition for this equation is: u = ( u s for uid solid interface boundary 0 for other boundaries (17) 3. Numerical results 3.1.…”

“…Therefore, the mechanical vibrations are one of the most important sources for EH. The mechanical vibration energy can be converted to electrical energy by using electromagnetic [14][15][16], piezoelectric [17][18][19], and electrostatic [20][21][22] mechanisms. The piezoelectric transduction has some advantages such as high power density, very simple design, and very small size [23][24][25][26] in comparison with other alternatives.…”

Numerical Modeling of Flow-Driven Piezoelectric Energy Harvesting Devices

“…This gives rise to ongoing transfer of flow energy to the structural oscillator and is called dynamic instability. Flutter response of a piezoelectrically damped cantilever pipe utilizing such flow instabilities was studied by [6]. Energy harvesting from fluid flows with attached electrical circuit was studied with a more comprehensive model by [19].…”

“…This prevented accounting for any change in harvester's properties during operating conditions. In another model developed in [6], a coupled FEM-circuit method was presented to account for the modeling of electrical circuits where the energy harvester was modeled using finite elements and the coupled to the electrical part modeled using a SPICE simulator. This method had comparable advantages to the model in [5] but is computationally expensive and does not provide a realistic representation of the strongly-coupled physics.…”

Optimization of the Electrical and Mechanical Parameters of a Vibration Energy Harvester

“…However, many of these models usually simplify either the mechanical domain, considering a SDOF spring-mass-damper models and equivalent circuit techniques [2,3,20], or the electrical domain, using a single resistor to represent the external load. Such models may not correspond to reality.…”