scholarly journals Improved Interface Circuit for Enhancing the Power Output of a Vibration-Threshold-Triggered Piezoelectric Energy Harvester

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3830
Author(s):  
Jiqiang Liu ◽  
Junjie Yang ◽  
Ruofeng Han ◽  
Qisheng He ◽  
Dacheng Xu ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Piezoelectric Material ◽  
Output Power ◽  
Energy Harvester ◽  
Equivalent Circuit Model ◽  
Stage Structure ◽  
Circuit Model ◽  
Interface Circuit ◽  
Piezoelectric Energy ◽  
Vibration Threshold

The vibration-threshold-triggered piezoelectric energy harvester is a new type of piezoelectric energy harvester with a two-stage structure, which can generate electricity in a low frequency environment and recognize vibration intensity at the same time. In this study, a theoretical model of a vibration-threshold-triggered energy harvester was examined, and an equivalent circuit model of the energy harvester was obtained. Then, an interface circuit was proposed that can significantly improve the output power of the energy harvester. The interface circuit achieved impedance matching with the piezoelectric material to maximize the energy collected from the energy harvester. First, we calculated and analyzed the impedance characteristics of the energy harvester, based on the equivalent circuit model. It was found that because the piezoelectric material is in resonance as the energy harvester is in operation, the corresponding impedance is almost resistance. Therefore, a resistance-matching strategy was proposed. Last, we proposed an interface circuit with adjustable input impedance to achieve resistance matching. The experimental results show that the proposed interface circuit can increase the output power of the energy harvester by 48.1–55.7% over that achieved with the standard interface circuit.

Investigation of Output Power and Efficiency of Wound-Rotor Brushless Doubly-Fed Machine

2012 ◽  
Vol 516-517 ◽  
pp. 1604-1609
Author(s):  
Jun Zhang ◽  
Xue Fan Wang
Keyword(s):  
Equivalent Circuit ◽  
Output Power ◽  
Power Distribution ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Maximum Output ◽  
The Core ◽  
Doubly Fed ◽  
Doubly Fed Machine ◽  
The Relationship

Brushless Doubly-fed Machine (BDFM) is a new type of the induction machine, which has wide application in the fields of variable-speed generator and drive systems. The key factor affecting its performance is the rotor structure. In this paper, taking wound-rotor BDFM for instance, firstly, according to the relationship between the equivalent circuit parameters of the BDFM, the core equivalent circuit model of the BDFM has been derived. Secondly, based on the core equivalent circuit model and the constraints of electromagnetic load, the power distribution between the power and control windings and the constraint condition of maximum output of active power has been obtained. Thirdly, according to the simplified model of the equivalent circuit, the copper loss and the relationship between the output power and efficiency of the machine have been investigated. Finally, the anlysis results are verified by the experimental data.

scholarly journals Bandwidth Broadening of Piezoelectric Energy Harvesters Using Arrays of a Proposed Piezoelectric Cantilever Structure

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 973
Author(s):  
Marwa S. Salem ◽  
Shimaa Ahmed ◽  
Ahmed Shaker ◽  
Mohammad T. Alshammari ◽  
Kawther A. Al-Dhlan ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Piezoelectric Material ◽  
Output Power ◽  
Energy Harvester ◽  
Vibration Source ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Narrow Bandwidth ◽  
Cantilever Structure ◽  
Bandwidth Broadening

One of the most important challenges in the design of the piezoelectric energy harvester is its narrow bandwidth. Most of the input vibration sources are exposed to frequency variation during their operation. The piezoelectric energy harvester’s narrow bandwidth makes it difficult for the harvester to track the variations of the input vibration source frequency. Thus, the harvester’s output power and overall performance is expected to decline from the designed value. This current study aims to solve the problem of the piezoelectric energy harvester’s narrow bandwidth. The main objective is to achieve bandwidth broadening which is carried out by segmenting the piezoelectric material of the energy harvester into n segments; where n could be more than one. Three arrays with two, four, and six beams are shaped with two piezoelectric segments. The effect of changing the length of the piezoelectric material segment on the resonant frequency, output power, and bandwidth, as well as the frequency response is investigated. The proposed piezoelectric energy harvesters were implemented utilizing a finite element method (FEM) simulation in a MATLAB environment. The results show that increasing the number of array beams increases the output power and bandwidth. For the three-beam arrays, at n equals 2, 6 mW output power and a 9 Hz bandwidth were obtained. Moreover, the bandwidth of such arrays covered around 5% deviation from its resonant frequency. All structures were designed to operate as a steel wheel safety sensor which could be used in train tracks.

scholarly journals Orthogonal Piezoelectric Energy Harvester for Low Frequency Applications: Modeling and Experimental Validation

2019 ◽  
Vol 8 (4) ◽  
pp. 6268-6274
Keyword(s):  
Piezoelectric Material ◽  
Output Power ◽  
Experimental Validation ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Galvanized Steel ◽  
Rotational Inertia ◽  
Acceptable Error ◽  
Piezoelectric Energy

The use of piezoelectric energy harvesters in low frequency applications is a classic problem due to the high elastic modulus of currently available piezoelectric materials. Furthermore, the output power is proportional to the third power of the excitation frequency. Higher excitation amplitudes or an increase in the piezoelectric material can produce a high output power. However, this is not feasible for weak environmental vibration, and using more piezoelectric material would incur a higher cost so this is not an attractive option. This article proposes an L-shaped piezoelectric energy harvester that amplifies the excitation amplitude with the aid of an extension arm. The effects of bending and rotational inertia are considered when modelling the open-circuit voltage that can be generated by the harvester. Experimental validation is carried out using zinc, aluminium and galvanized steel extension arms. The prediction model provides a good estimation of the results with acceptable error percentages for linear elastic extension arms. It is found that the proposed harvester geometry generates more output voltage for all lengths of extension arm, and the optimum lengths are different for each material. The use of a zinc extension arm generated 290 µW at 49 Hz, which is 55% greater than the power generated by a harvester without an extension arm that had a power density of 1.41 µW/mm3 .

SPICE Equivalent Circuit Model of Electrostatic Energy Harvester including Electrostatic Force

2016 ◽  
Vol 136 (8) ◽  
pp. 323-329
Author(s):  
Koji Sonoda ◽  
Keidai Minami ◽  
Naoki Miwatani ◽  
Kensuke Kanda ◽  
Takayuki Fujita ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Energy Harvester ◽  
Electrostatic Force ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Electrostatic Energy
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