Performance Evaluation of Suspended Energy Harvesting Backpack Using Half-Wave Mechanical Rectification

Author(s):  
Jia Mi ◽  
Qiaofeng Li ◽  
Mingyi Liu ◽  
Xiaofan Li ◽  
Lei Zuo

Abstract Human beings are becoming more and more dependent on electronic devices, such as smart phones, smart watches, GPS, etc. This paper presents the design, modeling and testing of a novel suspended energy harvesting backpack using half-wave mechanical rectification. The proposed half-wave rectification mechanism can convert bidirectional linear vibration into unidirectional rotation with nonlinear inertia. Compared with full-wave mechanical rectification, the proposed half-wave rectification is designed only to convert the motion in one of the vibration directions while remaining idle in the other direction. Numerical simulation shows the proposed half-wave rectification based suspended energy harvesting backpack can obtain about two times of the average output power as the previous full-wave rectification design while also maintaining larger output power in the wideband frequency range. Bench test results indicate that the proposed half-wave rectification-based energy harvesting backpack can harvest 6.7 W (peak)/2.1 W (average) under 2 Hz and 6 mm excitation with a 31.8 kg payload, which is a significant improvement compared with 1.9 W(peak)/0.9 W (average) for the counterpart of full-wave rectification system. In addition, bench test results also validate the energy harvesting in wideband frequency range. Treadmill tests demonstrate an average power range of 1.2–11.0 W under walking speeds of 3.2–6.4 km/h with a 13.6 kg payload.

Author(s):  
Ziheng Zhu ◽  
Lin Xu ◽  
Mohamed A. A. Abdelkareem ◽  
Junyi Zou ◽  
Jia Mi

Abstract With the recent energy crisis, the new energy harvesting technologies have become one of the hot spots in engineering academic research and industrial applications. By its wide range of application fields, vibration energy harvesting technologies have been gradually developed and utilized in which an efficient and stable harvester technology is one of the recent key problems. In order to improve energy harvesting efficiency and reduce energy loss caused by motor inertial commutation, many mechanical structures or hydraulic structures that convert reciprocating vibration energy into single direction rotation of motor are proposed. Although these methods can improve energy harvesting efficiency, they can have negative effects in some cases, especially in the case of vibration energy harvesting from human beings. This paper proposes a vibration harvesting mechanism with mechanical rectification filter function applied to backpack. The prototype model of the system was established in SolidWorks and imported into ADAMS. Thereafter, dynamic analyses of mechanical rectification filtering characteristics and meshing characteristics of one-way clutch were simulated in ADAMS. Based on ADAMS, parametric design analysis and its influence on the mechanical rectification characteristics were investigated. The simulation results were validated by bench test results. Simulation results is done by ADAMS and the results match well with bench test results.


2019 ◽  
Vol 19 (09) ◽  
pp. 1950102 ◽  
Author(s):  
Xiaobiao Shan ◽  
Haigang Tian ◽  
Tao Xie

This paper focuses on the aeroelastic vibration energy harvesting performance of a wing panel. A nonlinear mathematical model of fluid-structure-electric coupling field was established based on the aeroelastic vibration equation and piezoelectric equation. Numerical analysis was performed to explore the influences of the airflow velocity and the piezoelectric material structural parameters on both the dynamic response and the energy harvesting performance. A small experimental wind tunnel and several prototypes of energy harvesters of the wing panel were designed and fabricated. The experimental results show that the vibration amplitude and output power of the wing panel increase with the airflow velocity; the average output power first increases until it attains the maximum values, and then decreases with the increase of the dimensionless length ([Formula: see text]/[Formula: see text] and the thickness of the piezoelectric patch. It shows that the theoretical and experimental results are in good agreement. The experimental optimal output power is 3[Formula: see text]mW at the airflow velocity of 12[Formula: see text]m/s, and the piezoelectric patch length, width and thickness of 40, 20 and 0.2[Formula: see text]mm, respectively. This work provides an effective theoretical and experimental basis for studying energy harvesting and vibration control of airfoil aircrafts.


Author(s):  
Ildu Kim ◽  
Junghwan Moon ◽  
Jungjoon Kim ◽  
Seunghoon Jee ◽  
Junghwan Son ◽  
...  

This paper demonstrates a highly efficient 3-stage Doherty power amplifier (PA) employing an envelope tracking (ET) technique. The ‘3-stage’ Doherty PA is the most efficient architecture for a high peak-to-average power ratio (PAPR) signal among the various Doherty PAs. However, because of the lower peaking biases than those of the ‘N-way’ Doherty PA, the proper load modulation is hard to be achieved. To get proper modulation, the peaking PAs' gate biases have been adaptively controlled using the ET technique, and the peak power and maximum efficiency characteristic along the backed-off output power region is successfully achieved. By ADS and Matlab simulations, the overall behavior of the 3-stage Doherty PA employing the ET technique has been fully analyzed. To maximize the overall efficiency of the proposed 3-stage Doherty PA, the unit PA has been designed using class F−1 PA. For verification, the amplifier is implemented using 5 W and 10 W PEP LDMOSFETs for the 802.16e mobile world interoperability for microwave access (WiMAX) at 1 GHz with a 8.5 dB PAPR. The measured drain efficiency of the proposed 3-stage Doherty PA is 55.5% at an average output power of 37 dBm, which is a 7.54 dB backed-off output power. The digital feedback predistortion (DFBPD) algorithm has been used to linearize the proposed PA considering the ET technique. After linearization, the −33.15 dB of relative constellation error (RCE) performance is achieved, satisfying the system specification. These results show that the 3-stage Doherty employing the ET technique and saturated PA is the most suitable PA for the highly efficient and linear transmitter.


2021 ◽  
Vol 31 (1) ◽  
pp. 27-39
Author(s):  
Essa Ibrahim Essa ◽  
Mshari A. Asker ◽  
Fidan T. Sedeeq

Abstract Using optical add–drop multiplexer/remover multiplexer (OADM), it is possible to add or remove wavelengths and change or route them through the various nodes and networks. At this moment, key problems in add–drop multiplexer (ADM) are the bandwidth, modulation format, and reuse wavelength. In this article, the Optisystem software simulation is used as a platform to design, test, and verify the method applied to the current work; the OADM is proposed based on the metro network to get distribution between nodes over a transmission link; OADM analysis was presented with four channels (193.1, 193.2, 193.3, and 193.4 THz) at total bandwidth of 1.6 Tb/s, none-return-to-zero (NRZ), and return to zero coding types. Experiment one shows that the average output power is −17.997 dBm, the average drop power is −17.997 dBm, and the average add power is −18.338 dBm, the average gain is −0.0429 dB, the average noise figure is 0 dB, the average power input signal is 10.679 dBm, the average of power output signal is 10.633 dBm, and the average output optical signal-to-noise ratio (OSNR) is 0 dB, However, the second experiment shows that the average output power is −24.238 dBm, the average drop power is −24.288 dBm, and the average add power is −24.753 dBm, the average gain is −0.0417 dB, the average noise figure is 0 dB, average power input signal is 7.691 dBm, average of power output signal is 7.677 dBm, and the average output OSNR 0 dB. The system supports four input channels, four add channels, four output channels, and four drop channels. The results are acceptable after three spans of Solitons fiber with 600 km length, 200 km for each span. Nonetheless, it is believed that it is well justified to adopt these schemes in the current optical network with a low cost for overall expenditure.


Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2005 ◽  
Author(s):  
Catalina-Alice Brandus ◽  
Stefania Hau ◽  
Alin Broasca ◽  
Madalin Greculeasa ◽  
Flavius-Marian Voicu ◽  
...  

A 5.0-at.% Nd-doped La0.64Gd0.41Sc2.95(BO3)4 (Nd:LGSB) borate laser crystal was successfully grown by the Czochralski method, for the first time to our knowledge. The spectroscopic properties of the grown crystal are discussed and 1 µm laser emission, under end-pumping with a fiber-coupled diode laser at 807 nm, is reported. A c-cut Nd:LGSB medium yielded 1.35 W continuous-wave output power at 0.63 overall optical-to-optical efficiency, with respect to the absorbed pump power, together with the high 0.68 slope efficiency. With an a-cut Nd:LGSB sample, 0.81 W output power at 0.52 optical-to-optical efficiency was obtained. The laser emission performances under quasi-continuous wave pumping are presented as well, for both c-cut and a-cut crystals. Passive Q-switching was investigated with a semiconductor saturable absorber mirror (SESAM). Laser pulses with 2.2 µJ energy and 32.8 ns durations were recorded from a-cut Nd:LGSB. The average output power reached 0.36 W at 1.55 W absorbed pump power. Passive mode-locking with SESAM was achieved in a long Z-type resonator. Ultrashort pulses with 0.19 W average power, 1.63 nJ energy, and 1.43 ps pulse duration, at 118 MHz repetition rate, are demonstrated for the a-cut Nd:LGSB medium.


2018 ◽  
Vol 150 ◽  
pp. 01012
Author(s):  
Muhamad Syazmie Bin Sepeeh ◽  
Farahiyah Binti Mustafa ◽  
Anis Maisarah Binti Mohd Asry ◽  
Sy Yi Sim ◽  
Mastura Shafinaz Binti Zainal Abidin

In this study, the development of operational amplifier (op-amp) based rectifier for piezoelectric energy harvesting applications was studied. The two stage op-amp full wave rectifier was used to convert the AC signal to DC signal voltage received by piezoelectric devices. The inverted half wave rectifier integrated with full wave rectifier were designed and simulated using MultiSIM software. The circuit was then fabricated onto a printed circuit board (PCB), using standard fabrication process. The achievement of this rectifier was able to boost up the maximum voltage of 5 V for input voltage of 800 mV. The output of the rectifier was in DC signal after the rectification by the op-amp. In term of power, the power dissipation was reduced consequently the waste power decreases. Future work includes optimization of the rectifying circuit to operate more efficiently can be made to increase the efficiency of the devices.


2018 ◽  
Vol 8 (6) ◽  
pp. 3530-3535
Author(s):  
A. Kumar ◽  
D. Sarkar ◽  
P. K. Sadhu

An efficacious and reliable power control technique has been developed which can be used to regulate the output power of a high-frequency full bridge series resonant inverter (HF-FBSRI) in an induction heating (IH) system. In this paper, a modified buck-boost converter is presented to control the DC link/bus voltage which maintains the IH system under resonant mode and optimizes the performance of the IH system. Controlled DC link/bus voltage has been applied to this HF- FBSRI to control the average output power in the IH system. Using this aimed control technique, a wide range of output powers has been controlled and consistent performance of the IH system has been achieved. ZVS switching technique has been used to reduce the switching losses. Varying average power has been obtained at different duty cycles ranging from 0.2 to 0.8 with variable DC link voltage and it has been corroborated using PSIM environment for an IH system rated at 5500W.


Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 621
Author(s):  
Tao Cao ◽  
Youjiang Liu ◽  
Wenhua Chen ◽  
Chun Yang ◽  
Jie Zhou

An analytical method to design a power amplifier (PA) with an optimized power added efficiency (PAE) trajectory for envelope tracking (ET) architecture is proposed. To obtain feasible matching solutions for high-efficiency performance of the PA in the dynamic supply operation, hybrid continuous modes (HCM) architecture is introduced. The design space for load impedances of the HCM PAs with nonlinear capacitance is deduced mathematically using the device’s embedding transfer network, without the necessity of using load-pull. The proposed design strategy is verified with the implementation of a GaN PA operating over the frequency range of 1.9 GHz to 2.2 GHz with PAE between 67.8% and 72.4% in the 6.7 dB back-off power region of the ET mode. The ET experimental system was set up to evaluate the application of the PA circuit. Measurement results show that the ET PA at 2.1 GHz reaches the efficiency of 61%, 54%, 44% and an error vector magnitude (EVM) of 0.32%, 0.60%, 0.67% at an average output power of 34.4 dBm, 34.2 dBm, 34.1 dBm for 6.7 dB peak-to-average power ratios (PAPR) signals with 5 MHz, 10 MHz, and 20 MHz bandwidths, respectively. Additionally, tested by a 20 MHz bandwidth 16 quadrature amplitude modulation (QAM) signal, 41.8% to 49.2% efficiency of ET PA is achieved at an average output power of 33.5 dBm to 35.1 dBm from 1.9 GHz to 2.2 GHz.


Fuels ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 168-178
Author(s):  
Marzia Quaglio ◽  
Daniyal Ahmed ◽  
Giulia Massaglia ◽  
Adriano Sacco ◽  
Valentina Margaria ◽  
...  

Sediment microbial fuel cells (SMFCs) are energy harvesting devices where the anode is buried inside marine sediment, while the cathode stays in an aerobic environment on the surface of the water. To apply this SCMFC as a power source, it is crucial to have an efficient power management system, leading to development of an effective energy harvesting technique suitable for such biological devices. In this work, we demonstrate an effective method to improve power extraction with SMFCs based on anodes alternation. We have altered the setup of a traditional SMFC to include two anodes working with the same cathode. This setup is compared with a traditional setup (control) and a setup that undergoes intermittent energy harvesting, establishing the improvement of energy collection using the anodes alternation technique. Control SMFC produced an average power density of 6.3 mW/m2 and SMFC operating intermittently produced 8.1 mW/m2. On the other hand, SMFC operating using the anodes alternation technique produced an average power density of 23.5 mW/m2. These results indicate the utility of the proposed anodes alternation method over both the control and intermittent energy harvesting techniques. The Anode Alternation can also be viewed as an advancement of the intermittent energy harvesting method.


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