Upper Bound of Power Harvested by an On-Off Electrical Damping in a State Space System

2021 ◽  
Author(s):  
Viet, Duc La
Keyword(s):  
Upper Bound ◽  
Switching Time ◽  
Linear Time ◽  
Optimal Switching ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Linear Time Invariant ◽  
Piezoelectric Energy ◽  
Variable Function ◽  
Electrical Damping

Abstract This paper presents the theoretical upper bound of the harvested power, which is amplified by a generalized electrical damping switching controller in a linear time invariant system. The upper bound is found by maximizing a single-variable function with respect to the switching time. The upper bound shows the possibility of raising the power-frequency curve over the optimal passive curves reported in literature. The optimal switching time of the upper bound shows the mechanics that determine the optimality. The upper bound solution is not only a good benchmark to evaluate but also a clear guide to design any other practical controllers. To demonstrate these two benefits, four examples in literature were revisited: the Single DOF electromagnetic and piezoelectric energy harvesters, the Dual-mass vibration energy harvester and the quarter car hybrid electromagnetic suspension. A demonstration controller is proposed in all examples. The upper bound is used to evaluate the demonstration controller. The optimal switching time is used to explain the reason of a good or bad controller.

On Mathematical Modeling of Piezoelectric Energy Harvesters

2014 ◽  
Vol 953-954 ◽  
pp. 655-658 ◽  
Author(s):  
Guang Qing Shang ◽  
Hong Bing Wang ◽  
Chun Hua Sun
Keyword(s):  
Mathematical Modeling ◽  
Energy Harvesting ◽  
Energy Harvester ◽  
Vibration Energy ◽  
Piezoelectric Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Energy Harvesting System ◽  
Piezoelectric Vibration

Energy harvesting system has become one of important areas of ​​research and develops rapidly. How to improve the performance of the piezoelectric vibration energy harvester is a key issue in engineering applications. There are many literature on piezoelectric energy harvesting. The paper places focus on summarizing these literature of mathematical modeling of piezoelectric energy harvesting, ranging from the linear to nonlinear, from early a single mechanical degree to piezoaeroelastic problems.

Heartbeat Energy Harvesting Using the Fan-Folded Piezoelectric Beam Geometry

2015 ◽  
Author(s):  
M. H. Ansari ◽  
M. Amin Karami
Keyword(s):  
Natural Frequency ◽  
Energy Harvester ◽  
Low Frequency ◽  
Mode Shapes ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Mechanical Coupling ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam

A three dimensional piezoelectric vibration energy harvester is designed to generate electricity from heartbeat vibrations. The device consists of several bimorph piezoelectric beams stacked on top of each other. These horizontal bimorph beams are connected to each other by rigid vertical beams making a fan-folded geometry. One end of the design is clamped and the other end is free. One major problem in micro-scale piezoelectric energy harvesters is their high natural frequency. The same challenge is faced in development of a compact vibration energy harvester for the low frequency heartbeat vibrations. One way to decrease the natural frequency is to increase the length of the bimorph beam. This approach is not usually practical due to size limitations. By utilizing the fan-folded geometry, the natural frequency is decreased while the size constraints are observed. The required size limit of the energy harvester is 1 cm by 1 cm by 1 cm. In this paper, the natural frequencies and mode shapes of fan-folded energy harvesters are analytically derived. The electro-mechanical coupling has been included in the model for the piezoelectric beam. The design criteria for the device are discussed.

scholarly journals Crack Protective Layered Architecture of Lead-Free Piezoelectric Energy Harvester in Bistable Configuration

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5808
Author(s):  
Ondrej Rubes ◽  
Zdenek Machu ◽  
Oldrich Sevecek ◽  
Zdenek Hadas
Keyword(s):  
Energy Harvester ◽  
Lead Free ◽  
Vibration Energy Harvester ◽  
Ultra Low Power ◽  
Energy Harvesters ◽  
Layered Architecture ◽  
Piezoelectric Energy ◽  
Wide Range ◽  
Ultra Low Power Devices ◽  
Novel Design

Kinetic piezoelectric energy harvesters are used to power up ultra-low power devices without batteries as an alternative and eco-friendly source of energy. This paper deals with a novel design of a lead-free multilayer energy harvester based on BaTiO3 ceramics. This material is very brittle and might be cracked in small amplitudes of oscillations. However, the main aim of our development is the design of a crack protective layered architecture that protects an energy harvesting device in very high amplitudes of oscillations. This architecture is described and optimized for chosen geometry and the resulted one degree of freedom coupled electromechanical model is derived. This model could be used in bistable configuration and the model is extended about the nonlinear stiffness produced by auxiliary magnets. The complex bistable vibration energy harvester is simulated to predict operation in a wide range of frequency excitation. It should demonstrate typical operation of designed beam and a stress intensity factor was calculated for layers. The whole system, without presence of cracks, was simulated with an excitation acceleration of amplitude up to 1g. The maximal obtained power was around 2 mW at the frequency around 40 Hz with a maximal tip displacement 7.5 mm. The maximal operating amplitude of this novel design was calculated around 10 mm which is 10-times higher than without protective layers.

scholarly journals The Effect of Axial Displacement of Magnets in Piezoelectric Energy Harvester

2018 ◽  
Vol 7 (3.7) ◽  
pp. 95
Author(s):  
Li Wah Thong ◽  
Yu Jing Bong ◽  
Swee Leong Kok ◽  
Roszaidi Ramlan
Keyword(s):  
Frequency Spectrum ◽  
Power Output ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Operational Frequency ◽  
And Performance

The utilization of vibration energy harvesters as a substitute to batteries in wireless sensors has shown prominent interest in the literature. Various approaches have been adapted in the energy harvesters to competently harvest vibrational energy over a wider spectrum of frequencies with optimize power output.   A typical bistable piezoelectric energy harvester, where the influence of magnetic field is induced into a linear piezoelectric cantilever, is designed and analyzed in this paper. The exploitations of the magnetic force specifically creates nonlinear response and bistability in the energy harvester that extends the operational frequency spectrum for optimize performance.  Further analysis on the effects of axial spacing displacement between two repulsive magnets of the harvester, in terms of x-axis (horizontal) and z-axis (vertical) on its natural resonant frequency and performance based on the frequency response curve are investigated for realizing optimal power output. Experimental results show that by selecting the optimal axial spacing displacement, the vibration energy harvester can be designed to produce maximized output power in an improved broadband of frequency spectrum.  

An upper bound of mean-square error in state estimation with quantized measurements

2018 ◽  
Vol 41 (2) ◽  
pp. 582-590 ◽  
Author(s):  
Bin Hu ◽  
Zhiping Shen ◽  
Weizhou Su
Keyword(s):  
State Estimation ◽  
Upper Bound ◽  
Linear Time ◽  
Estimation Error ◽  
Data Rate ◽  
The State ◽  
Design Parameters ◽  
Discrete Time System ◽  
State Estimator ◽  
Linear Time Invariant

In this paper, we study the state estimation for a linear time-invariant (LTI) discrete-time system with quantized measurements. The quantization law under consideration has a time-varying data rate. To cope with nonlinearities in quantization laws and to analyse stability in the state estimation problem, a Kalman-filter-based sub-optimal state estimator is developed and an upper bound of its estimation error covariance is minimized. It turns out that, to guarantee the convergence of the upper bound, the averaged data rate of the quantization law must be greater than a minimum rate. This minimum data rate for the quantization law is presented in terms of the poles of the system and design parameters in the state estimator. Numerical examples are presented to illustrate the results in this work.

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