scholarly journals Load Resistance Optimization of a Magnetically Coupled Two-Degree-of-Freedom Bistable Energy Harvester Considering Third-Harmonic Distortion in Forced Oscillation

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2668
Author(s):  
Jinhong Noh ◽  
Pilkee Kim ◽  
Yong-Jin Yoon
Keyword(s):  
External Load ◽  
Energy Harvester ◽  
Impedance Matching ◽  
Harmonic Distortion ◽  
Load Resistance ◽  
Third Harmonic ◽  
The Third ◽  
Power Outputs ◽  
Two Degree Of Freedom ◽  
Bistable Energy Harvester

In this study, the external load resistance of a magnetically coupled two-degree-of-freedom bistable energy harvester (2-DOF MCBEH) was optimized to maximize the harvested power output, considering the third-harmonic distortion in forced response. First, the nonlinear dynamic analysis was performed to investigate the characteristics of the large-amplitude interwell motions of the 2-DOF MCBEH. From the analysis results, it was found that the third-harmonic distortion occurs in the interwell motion of the 2-DOF MCBEH system due to the nonlinear magnetic coupling between the beams. Thus, in this study, the third-harmonic distortion was considered in the optimization process of the external load resistance of the 2-DOF MCBEH, which is different from the process of conventional impedance matching techniques suitable for linear systems. The optimal load resistances were estimated for harmonic and swept-sine excitations by using the proposed method, and all the results of the power outputs were in excellent agreements with the numerically optimized results. Furthermore, the associated power outputs were compared with the power outputs obtained by using the conventional impedance matching technique. The results of the power outputs are discussed in terms of the improvement in energy harvesting performance.

scholarly journals Load Resistance Optimization of Bi-Stable Electromagnetic Energy Harvester Based on Harmonic Balance

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1505
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
External Load ◽  
Harmonic Balance ◽  
Energy Harvester ◽  
Load Resistance ◽  
Electromagnetic Energy ◽  
Analytic Approach ◽  
Accurate Estimation ◽  
Vibration Source ◽  
Optimal Load ◽  
Matching Techniques

In this study, a semi-analytic approach to optimizing the external load resistance of a bi-stable electromagnetic energy harvester is presented based on the harmonic balance method. The harmonic balance analyses for the primary harmonic (period-1T) and two subharmonic (period-3T and 5T) interwell motions of the energy harvester are performed with the Fourier series solutions of the individual motions determined by spectral analyses. For each motion, an optimization problem for maximizing the output power of the energy harvester is formulated based on the harmonic balance solutions and then solved to estimate the optimal external load resistance. The results of a parametric study show that the optimal load resistance significantly depends on the inductive reactance and internal resistance of a solenoid coil––the higher the oscillation frequency of an interwell motion (or the larger the inductance of the coil) is, the larger the optimal load resistance. In particular, when the frequency of the ambient vibration source is relatively high, the non-linear dynamic characteristics of an interwell motion should be considered in the optimization process of the electromagnetic energy harvester. Compared with conventional resistance-matching techniques, the proposed semi-analytic approach could provide a more accurate estimation of the external load resistance.

scholarly journals Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors

2021 ◽  
Vol 13 (5) ◽  
pp. 2865 ◽  
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
Energy Harvester ◽  
Load Resistance ◽  
Oscillation Period ◽  
Ambient Vibration ◽  
Ambient Vibrations ◽  
Frequency Dependency ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Bistable Energy Harvester

In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.

A method to reduce harmonic distortion of MEMS accelerometer

2018 ◽  
Vol 32 (21) ◽  
pp. 1850246 ◽  
Author(s):  
Yi Hang Wang ◽  
Liang Yin ◽  
Dong Liang Chen ◽  
Ling Li ◽  
Xiao Wei Liu
Keyword(s):  
Harmonic Distortion ◽  
Effective Number ◽  
Interface Circuit ◽  
Mems Accelerometer ◽  
Third Harmonic ◽  
The Third ◽  
Noise Density ◽  
Sensitive Structure ◽  
Fifth Order ◽  
Unstable Problem

This paper recommends a method to reduce harmonic distortion of MEMS accelerometer. The fifth-order MEMS accelerometer interface circuit designed in this work used the Cascade-of-Integrators, Feedforward modulation structure. This paper analyzes and calculates the main sources of HD, the unstable problem brought by the vacuum encapsulation sensitive structure. The use of front-phase compensation and the increase in loop forward gain helps ensure the system’s stability as well as reduce the system harmonic distortion. Simulink is used to get the simulation results. After harmonic optimization, the third harmonic reached −141.83 dB, the Signal-to-Noise-and-Distortion-Ratio rose to 118.1 dB, the noise density is under 200 ng/Hz[Formula: see text], the effective number of bits rose up to 19.33 bits.

scholarly journals Design of 0.8–2.7 GHz High Power Class-F Harmonic-Tuned Power Amplifier with Parasitic Compensation Circuit

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiqun Cheng ◽  
Xuefei Xuan ◽  
Huajie Ke ◽  
Guohua Liu ◽  
Zhihua Dong ◽  
...  
Keyword(s):  
Power Amplifier ◽  
High Power ◽  
High Efficiency ◽  
Impedance Matching ◽  
Harmonic Suppression ◽  
Compensation Circuit ◽  
Third Harmonic ◽  
The Third ◽  
Saturated Output Power ◽  
Class F

The design, implementation, and measurements of a high efficiency and high power wideband GaN HEMT power amplifier are presented. Package parasitic effect is reduced significantly by a novel compensation circuit design to improve the accuracy of impedance matching. An improved structure is proposed based on the traditional Class-F structure with all even harmonics and the third harmonic effectively controlled, respectively. Also the stepped-impedance matching method is applied to the third harmonic control network, which has a positive effect on the expansion bandwidth. CGH40025F power transistor is utilized to build the power amplifier working at 0.8 to 2.7 GHz, with the measured saturated output power 20–50 W, drain efficiency 52%–76%, and gain level above 10 dB. The second and the third harmonic suppression levels are maintained at −16 to −36 dBc and −16 to −33 dBc, respectively. The simulation and the measurement results of the proposed power amplifier show good consistency.

scholarly journals Electromechanical Performance Analysis of the Hybrid Piezoelectric-Electromagnetic Energy Harvester under Rotary Magnetic Plucking Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Hongyan Wang ◽  
Jiarui Hu ◽  
Gang Sun ◽  
Liying Zou
Keyword(s):  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Average Power ◽  
Load Resistance ◽  
Electromagnetic Energy ◽  
Lumped Parameter Model ◽  
Model Parameters ◽  
Piezoelectric Energy ◽  
Power Inputs ◽  
Power Outputs

This paper presents an analysis of the hybrid piezoelectric-electromagnetic energy harvester (P-EMEH) driven by contactless rotary magnetic plucking. A lumped-parameter model of the hybrid P-EMEH is developed, and the model parameters are determined from the finite element analysis (FEA) method. A parametric study is conducted to investigate the effects of driving force parameters, load resistance, and electromechanical coupling strengths (EMCSs) on the maximal displacements and velocities, average power inputs and outputs, and energy efficiencies of the system for indicating the performance of the hybrid P-EMEH. The results show that the hybrid P-EMEH can obtain the improved power inputs by reducing the gyration radii of the rotary magnet and shortening the gaps between the two magnets. The structural vibrations can be strongly suppressed owing to the optimal piezoelectric power outputs, which can lead to the occurrence of valleys’ power of the electromagnetic element. At weak coupling, the hybrid P-EMEH can achieve higher power outputs than the single piezoelectric energy harvester (PEH) and the single electromagnetic energy harvester (EMEH). At strong coupling, the use of the PEH is more advantageous for energy harvesting due to wider power bandwidths at high dimensionless frequencies when compared with the hybrid P-EMEH. This work provides a fundamental understanding on the effect of load resistance and EMCSs on the dynamic and electrical characteristics of the magnetically plucked hybrid P-EMEH.

scholarly journals Phase-dependent dynamic potential of magnetically coupled two-degree-of-freedom bistable energy harvester

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Pilkee Kim ◽  
Minh Sang Nguyen ◽  
Ojin Kwon ◽  
Young-Jin Kim ◽  
Yong-Jin Yoon
Keyword(s):  
Energy Harvester ◽  
Degree Of Freedom ◽  
Dynamic Potential ◽  
Two Degree Of Freedom ◽  
Bistable Energy Harvester

Analysis of delamination of unimorph cantilever piezoelectric energy harvesters

2018 ◽  
Vol 29 (9) ◽  
pp. 1875-1883 ◽  
Author(s):  
Shan Zeng ◽  
Chunwei Zhang ◽  
Kaifa Wang ◽  
Baolin Wang ◽  
Li Sun
Keyword(s):  
Power Output ◽  
Failure Modes ◽  
Energy Harvester ◽  
Present Model ◽  
Load Resistance ◽  
Active Length ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Unimorph Cantilever ◽  
Power Outputs

Unimorph piezoelectric energy harvesters are typically a unimorph cantilever beam located on a vibrating host structure. Delamination is one of the major failure modes of such unimorph cantilevers and therefore is studied in this article. The delaminated cantilever unimorph is modeled with one through-width crack using four Euler beams connected at delamination edges. The governing equations, the corresponding boundary conditions, and the kinematic continuity conditions are derived based on the Hamiltonian principle. The solutions of the voltage and power output for the present model are derived. The influence of the position and the length of the delamination, frequency of input base excitation, and load resistance on the voltage and power output are discussed in detail. The results show that delamination in the unimorph of the energy harvester will impressively decrease the voltage and power outputs. Influences of the delamination located at the free end of the cantilever are more obvious. For a given active length of the delaminated cantilever energy harvester, it is useful to increase the overall length of the cantilever to obtain a higher voltage and power outputs.

scholarly journals Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3194
Author(s):  
Adrian Petris ◽  
Petronela Gheorghe ◽  
Tudor Braniste ◽  
Ion Tiginyanu
Keyword(s):  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Laser Pulses ◽  
Third Harmonic Generation ◽  
High Repetition Rate ◽  
Third Order ◽  
Third Harmonic ◽  
The Third ◽  
High Repetition ◽  
Gan Crystal

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.

Sign in / Sign up

Export Citation Format

Share Document