Piezoelectric Vibration Energy Harvesting System Research Articles

System-Level Coupled Modeling of Piezoelectric Vibration Energy Harvesting Systems by Joint Finite Element and Circuit Analysis

A practical piezoelectric vibration energy harvesting (PVEH) system is usually composed of two coupled parts: a harvesting structure and an interface circuit. Thus, it is much necessary to build system-level coupled models for analyzing PVEH systems, so that the whole PVEH system can be optimized to obtain a high overall efficiency. In this paper, two classes of coupled models are proposed by joint finite element and circuit analysis. The first one is to integrate the equivalent circuit model of the harvesting structure with the interface circuit and the second one is to integrate the equivalent electrical impedance of the interface circuit into the finite element model of the harvesting structure. Then equivalent circuit model parameters of the harvesting structure are estimated by finite element analysis and the equivalent electrical impedance of the interface circuit is derived by circuit analysis. In the end, simulations are done to validate and compare the proposed two classes of system-level coupled models. The results demonstrate that harvested powers from the two classes of coupled models approximate to theoretic values. Thus, the proposed coupled models can be used for system-level optimizations in engineering applications.

Chaotic Dynamics-Based Analysis of Broadband Piezoelectric Vibration Energy Harvesting Enhanced by Using Nonlinearity

Nonlinear magnetic forces are always used to enlarge resonant bandwidth of vibration energy harvesting systems with piezoelectric cantilever beams. However, how to determine properly the distance between two magnets is one of the key engineering problems. In this paper, the Melnikov theory is introduced to overcome it. Firstly, the Melnikov state-space model of the nonlinear piezoelectric vibration energy harvesting (PVEH) system is built. Based on it, chaotic dynamics mechanisms of achieving broadband PVEH by nonlinearity are exposed by potential function of the unperturbed nonlinear PVEH system. Then the corresponding Melnikov function of the nonlinear PVEH system is defined, based on which two Melnikov necessary conditions of determining the distance are obtained. Finally, numerical simulations are done to testify the theoretic results. The results demonstrate that the distance is closely related to the excitation amplitude and frequency once geometric and material parameters are fixed. Under a single-frequency excitation, the nonlinear PVEH system can generate a periodic vibration around a stable point, a large-amplitude vibration around two stable points, or a chaotic vibration. The proposed method is very valuable for optimally designing and utilizing nonlinear broadband PVEH devices in engineering applications.

Vehicle Sensor Self-Powered Technology Research Based on Piezoelectric

As a result of the electric vehicles popularity and the development of vehicles intelligent, the number of vehicle sensors surge, meanwhile, many defects of traditional energy supply are increasingly prominent, such as pollution and maintenance difficulties. Taking into account the vehicle vibration exist everywhere, we use the piezoelectric technology to collect vibration energy, and designs a piezoelectric vibration energy harvesting system to be used to solve the energy problem of micro-power sensor. In this paper, the system structure and the theoretical model are analyzed, and the mathematical model of the system vibration frequency and the piezoelectric output have been put forward, then a piezoelectric energy harvesting device is designed on the basis of simulation analysis. Experiments have been done to test the performance of its power generation in the case of resonance. The results showed that the theoretical model proposed in this paper can be a good predictor of the output characteristics of the system. As the resonance frequency is 16.5 Hz, acceleration is 0.5g, the maximum open circuit voltage of the system obtained is 3.5 volts, the optimum load resistance is 425kΩ, and the vibration energy collection device maximum load power is 14 uW. Conclusion: Greater energy could be caught to meet the vehicle sensor power supply needs with the use of super capacitor.

Vehicle Sensor Self-Powered Technology Research Based on Piezoelectric

As a result of the electric vehicles popularity and the development of vehicles intelligent, the number of vehicle sensors surge, meanwhile, many defects of traditional energy supply are increasingly prominent, such as pollution and maintenance difficulties. Taking into account the vehicle vibration exist everywhere, we use the piezoelectric technology to collect vibration energy, and designs a piezoelectric vibration energy harvesting system to be used to solve the energy problem of micro-power sensor. In this paper, the system structure and the theoretical model are analyzed, and the mathematical model of the system vibration frequency and the piezoelectric output have been put forward, then a piezoelectric energy harvesting device is designed on the basis of simulation analysis. Experiments have been done to test the performance of its power generation in the case of resonance. The results showed that the theoretical model proposed in this paper can be a good predictor of the output characteristics of the system. As the resonance frequency is 16.5 Hz, acceleration is 0.5g, the maximum open circuit voltage of the system obtained is 3.5 volts, the optimum load resistance is 425kΩ, and the vibration energy collection device maximum load power is 14 uW. Conclusion: Greater energy could be caught to meet the vehicle sensor power supply needs with the use of super capacitor.

A multi-degree of freedom piezoelectric vibration energy harvester with piezoelectric elements inserted between two nearby oscillators

A novel piezoelectric vibration energy harvesting system is proposed whose harvesting performance could be significantly enhanced by introducing one or multiple additional piezoelectric elements placed between every two nearby oscillators. The proposed two degree-of-freedom piezoelectric vibration harvester system is expected to extract 9.78 times more electrical energy than a conventional two degrees of freedom harvester system with only one piezoelectric element inserted close to the base. A parameter study of a multiple degree-of-freedom piezoelectric vibration energy harvester system has been conducted to provide a guideline for tuning its harvesting bandwidth and optimizing its design. Based on the analysis method of the two degrees of freedom piezoelectric vibration harvester system, a generalised MDOF piezoelectric vibration energy harvester with multiple pieces of piezoelectric elements inserted between every two nearby oscillators is studied. The harvested power values of the piezoelectric vibration energy harvesters of 1 to 5 degree-of-freedom have been compared while the total mass and the mass ratio of the oscillators are kept as constants. It is found that the greater numbers of degree-of-freedom of a PVEH with the more additional piezoelectric elements inserted between every two nearby oscillators would enable that system to harvest more energy. The first mode resonant frequency will be shifted to a low-frequency range when the numbers of degree-of-freedom increase.

Efficiency of piezoelectric mechanical vibration energy harvesting

Harvesting efficiency of a piezoelectric vibration energy harvesting system is investigated to provide design guidelines for harvesting devices with optimal performance. Harvesting power efficiency (η), defined as the ratio of device output power (Pout) to mechanical input power (Pin), is an essential but unexplored metric for comparison of harvesters operating in different power-input environments. Power extracted from piezoelectric harvesters has been of primary interest and proper accounting of mechanical input power and efficiency metrics has not been considered. Here, we present a closed form solution for harvesting efficiency that allows device comparison and furthermore, efficiency-optimized versus power-optimized electrical loading conditions are compared along with a case study. A key finding is that optimal design parameters for efficiency are quite different than optima for output power (e.g., a single optimum versus dual optima at different frequencies), requiring multi-objective design. These new findings provide guidelines on system parameters that can be manipulated for optimized performance in different ambient source conditions.

An Enhanced Piezoelectric Vibration Energy Harvesting System with Macro Fiber Composite

Self-power supply is a promising project in various applied conditions. Among this research area, piezoelectric material-based energy harvesting (EH) method has been researched in recent years due to its advantages. With the limitation of energy form acceptance range of EH circuit system, a sum of energy is not accessible to be obtained. To enlarge the EH quantity from the vibration, an enhanced piezoelectric vibration EH structure with piezoelectric film is developed in this work. Piezoelectric-based energy harvesting mechanism is primarily proposed in this work. The special-designed electric circuit for EH from macro fiber composite (MFC) is proposed and then analyzed. When the structure vibrates in its modes of frequencies, the experiments are developed to measure the EH effect. The energy harvested from the vibrating structure is analyzed and the enhanced effect is presented. The results indicate that, with the enhanced EH structure in this work, vibration energy from structure is obtained in a larger range, and the general EH quantity is enlarged.

PSPICE-Based Analyses of the Vibration Energy Harvester System With Multiple Piezoelectric Units

It has been a challenge to determine the optimal energy-storage capacitance in piezoelectric vibration energy harvesting (VEH) systems for a given working time. In this paper, the PSPICE software is used to determine the optimal energy-storage capacitance in a VEH system with one or more piezoelectric modules, for maximizing the energy harvesting capability, and to investigate the dependence of this optimum energy-storage capacitance on the device and working parameters. The simulation method is verified by experimental results. It is found that the optimal energy-storage capacitance increases with an increase of the clamped capacitance, working frequency, and working time of the piezoelectric modules. It is also found that the optimal energy-storage capacitance is proportional to the number of the piezoelectric modules used in the VEH system if the piezoelectric modules have close parameters.

Modeling and analysis of piezoelectric vibration energy harvesting system using permanent magnetics

Modeling and analyzing of the piezoelectric vibration energy harvester using permanent magnets are systematically investigated to facilitate the evaluation and optimization of such a harvester. We set up a distributed-parameter model for describing nonlinear dynamic behaviors of these harvesters，and present harmonic analytical solution by using harmonic balance method. An analysis is performed using the simulation model to determine the effects of the distance between two magnets, amplitude of acceleration, electrical load resistance on the level of the output power. The optimum resistive loads under different vibration frequencies and accelerations are also compared. The results show that the bistable configuration is applicable to a small excitation case, and the closer to the transition region the small excitation position, the more the power can be harvested. Conversely, the monostable hardening configuration is suited for the large excitation case, the corresponding optimal magnet distance is not close to the transition region. Furthermore, the large amplitude oscillation between two potential wells and small amplitude oscillation within one potential well also bring forth coexisting phenomena of high-energy response and low-energy response; the closer to the transition region the oscillation position, the more obivious the coexisting phenomenon is. It is also demonstrated that exciting frequency is a decisive factor of optimum load resistance.

Piezoelectric vibration energy harvesting system with an adaptive frequency tuning mechanism for intelligent tires

The high vibration levels inside a tire have the potential to generate electrical power using vibration based energy harvesting techniques. In this paper, the feasibility of using an inertial vibrating energy harvester unit to power a sensor module inside the tire is assessed. The harvester unit is adapted to the tire vibration spectra and the superimposed acceleration signal. First prototypes demonstrate power generation capabilities sufficient enough to transmit tire sensor data multiple times per minute. To optimize the harvester performance with changing dominant tire vibration frequencies, a novel artificial neural network (ANN) based closed loop system capable of ensuring broad band operations has been proposed. By presenting a batteryless power supply unit, the proposed system addresses one of the key challenges in the realization of the intelligent tire concept.

An Integrated High-Performance Active Rectifier for Piezoelectric Vibration Energy Harvesting Systems

In this letter, a highly efficient active full-bridge rectifier is proposed for piezoelectric (PE) vibration energy harvesting systems. By replacing the passive diodes with an operational amplifier-controlled active counterpart and adding a switch in parallel with the transducer, the proposed rectifier solves the dc-offset problem of the comparator-based active diode, minimizes the voltage drop along the conduction path, and extracts more power from the transducer, all of which lead to better power extraction and conversion capability. The proposed rectifier, implemented in 0.18-μm CMOS technology, shows 90% power conversion efficiency and 81 μW output power, with values corresponding to 1.5 times and 3.4 times the values for a conventional full-bridge rectifier.