scholarly journals A self-oscillating h.f. power generator with a Class E resonant amplifier

2013 ◽  
Vol 61 (2) ◽  
pp. 527-534 ◽  
Author(s):  
M. Mikołajewski
Keyword(s):  
High Efficiency ◽  
Control Method ◽  
Power Sources ◽  
Power Generator ◽  
Power Generators ◽  
Theoretical Predictions ◽  
Proposed Modification ◽  
Generator Design ◽  
Good Agreement ◽  
Class E

Abstract Self-oscillating h.f. power generators with a Class E amplifier are used as industrial high-efficiency h.f. power sources. In the paper a modification of the classic Class E generator by applying an additional capacitor in the matching and feedback circuit is presented. The proposed solution increases the degree of freedom in the generator design and can noticeably reduce its cost by eliminating the need for the use of high-value h.f. capacitors in the feedback loop divider. The self-oscillating Class E generator (150 W/6.78 MHz) with the proposed modification has been designed, built and its parameters were measured. Theoretical predictions were in a good agreement with experimental results. Moreover, the burst control method of the output power in the generator has also been presented

scholarly journals Design of a High-Power High-Efficiency Multi-Receiver Wireless Power Transfer System

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1308
Author(s):  
Yuyu Zhu ◽  
Hanyu Zhang ◽  
Zuming Wang ◽  
Xin Cao ◽  
Renyin Zhang
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
High Efficiency ◽  
Control Method ◽  
Experimental Models ◽  
Wireless Power ◽  
Multiple Receivers ◽  
Combined Operation ◽  
Wireless Power Transfer System ◽  
Good Agreement

This paper proposes a new control method to regulate the power flow into multiple receivers. This system consists of one transmitter controller and three receiver controllers. They work independently to decide the power distribution with their combined operation. The simulated and experimental models have been built, and the experimental results are in good agreement with the theoretical analysis results. The proposed method is robust, flexible, and generalizable, and can be employed under various wireless charging conditions.

Theoretical and Experimental Investigation of Elevator Cable Dynamics and Control

2005 ◽  
Vol 128 (1) ◽  
pp. 66-78 ◽  
Author(s):  
W. D. Zhu ◽  
Y. Chen
Keyword(s):  
Control Method ◽  
Upward Movement ◽  
High Rise ◽  
Cable Dynamics ◽  
Theoretical Predictions ◽  
Dynamics And Control ◽  
And Control ◽  
Elevator Cable ◽  
Parameter Estimation Techniques ◽  
Good Agreement

The vibratory energy of a moving cable in an elevator increases in general during upward movement. A control method is presented to dissipate the energy associated with the lateral vibration of the cable. A novel experimental method is developed to validate the theoretical predictions for the uncontrolled and controlled lateral responses of a moving cable in a high-rise elevator. This includes the design and fabrication of a scaled elevator, experimental setup, and development of measurement and parameter estimation techniques. Experimental results show good agreement with the theoretical predictions.

Evaluation and Modeling of Power Generator with Bimorph PZT Cantilever

2006 ◽  
Vol 966 ◽  
Author(s):  
Dongna Shen ◽  
Jyoti Ajitsria ◽  
Song-Yul Choe ◽  
Dong-Joo Kim
Keyword(s):  
Resonant Frequency ◽  
Energy Conversion ◽  
High Efficiency ◽  
Proof Mass ◽  
Large Strain ◽  
Power Generator ◽  
Power Generators ◽  
Operation Conditions ◽  
Remote Sensor ◽  
Cantilever Structure

ABSTRACTBattery, the traditional power source in present wireless remote sensor systems, has large volume and requires large amount of maintenance. Therefore, piezoelectric power generator has been studied for a potential alternative to battery by scavenging or harvesting energy from its operating environment. The efforts for investigating such piezoelectric device have been especially enhanced by the miniaturization requirement and low energy consumption of advanced devices as well as the sufficient vibration energy sources and its high conversion efficiency. To utilize piezoelectric material as energy conversion transducer, the device should be designed to operate with high efficiency and simple configuration. PZT (Lead Zirconium Titanate) is an excellent candidate for energy conversion because of its large piezoelectric constant and coupling coefficient.In this study, power generators based on bimorph cantilever structure were designed and fabricated using PZT ceramic benders due to accessible large strain or energy. The parameters influencing the output energy of piezoelectric bimorph cantilevers including the dimensions of the cantilever and the proof mass, the loading ways of the proof mass, and the resonant frequency of the cantilever were systematically investigated. The robustness of cantilever structure was also considered for implementing piezoelectric power conversion devices in harsh environments. The final optimal design was realized by considering the balance between the output power and the safety factor through numerical analysis. The energy density generated by the optimized piezoelectric devices was higher than 1 mW at 1-g vibration, which could be enough to operate microsensor systems. To broaden the operation conditions, multiple-resonant frequency device was also explored.

scholarly journals A Transformer Class E Amplifier

2014 ◽  
Vol 63 (4) ◽  
pp. 621-633 ◽  
Author(s):  
Miroslaw Mikolajewski
Keyword(s):  
Output Power ◽  
High Efficiency ◽  
Supply Voltage ◽  
Maximum Output Power ◽  
Switching Frequency ◽  
Maximum Output ◽  
Theoretical Predictions ◽  
Inductive Component ◽  
Isolation Transformer ◽  
Class E

Abstract In a high-efficiency Class E ZVS resonant amplifier a matching and isolation transformer can replace some or even all inductive components of the amplifier thus simplifying the circuit and reducing its cost. In the paper a theoretical analysis, a design example and its experimental verification for a transformer Class E amplifier are presented. In the experimental amplifier with a transformer as the only inductive component in the circuit high efficiency ηMAX = 0.95 was achieved for supply voltage VI = 36 V, maximum output power POMAX = 100 W and the switching frequency f = 300 kHz. Measured parameters and waveforms showed a good agreement with theoretical predictions. Moreover, the relative bandwidth of the switching frequency was only 19% to obtain output power control from 4.8 W to POMAX with efficiency not less than 0.9 in the regulation range.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Main problems of import subsumption in domestic engineering, applicable to small-power electric generator installations

2018 ◽  
Vol 1 (1) ◽  
pp. 46-51 ◽  
Author(s):  
A. V. Shelgunov
Keyword(s):  
Low Power ◽  
Import Substitution ◽  
Power Generator ◽  
Small Power ◽  
Domestic Production ◽  
Power Generators ◽  
Electric Generator ◽  
Generating Sets ◽  
Current State ◽  
Generator Sets

Subject: the subject of the study are low-power generator sets with a power of up to 30 kW.Materials and methods: in this paper, the main domestic legislative documents regulating the requirements for products. An assessment is made of the current state of Russian engine building.Results: the detailed analysis of the modern domestic market of power generating units with a capacity of up to 30 kW is made, the main problems in the field of domestic production of  electric power generators in the range up to 30 kW are revealed, and the prospects for import substitution of gasoline and diesel engines are noted.Conclusions: almost complete absence of the market of domestic low-power generating sets is established, insufficient measures taken to support domestic producers are noted, measures are  proposed for the development of domestic production of power units in the range of up to 30 kW.

A High Efficiency Class-E Power Amplifier Over a Wide Power Range Using a Look-Up Table Based Dynamic Biasing Scheme

2015 ◽  
Vol E98.C (4) ◽  
pp. 377-379
Author(s):  
Jonggyun LIM ◽  
Wonshil KANG ◽  
Kang-Yoon LEE ◽  
Hyunchul KU
Keyword(s):  
Power Amplifier ◽  
High Efficiency ◽  
Look Up Table ◽  
Dynamic Biasing ◽  
Class E

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

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