Compensation of harmonics and unbalance caused by a variable load using a dynamic phase balancer

2005 ◽  
Author(s):  
G. ó hEidhin
Keyword(s):  
Variable Load ◽  
Dynamic Phase

Leadership and member voice in action teams: Test of a dynamic phase model.

2018 ◽  
Vol 103 (1) ◽  
pp. 97-110 ◽  
Author(s):  
Crystal I. C. Farh ◽  
Gilad Chen
Keyword(s):  
Phase Model ◽  
Dynamic Phase

ENERGY SAVING MODES OF INDUCTION MOTORS WITH VARIABLE LOAD

2019 ◽  
Vol 19 (3) ◽  
pp. 142-150
Author(s):  
С.О. Квітка ◽  
◽  
О.Ю. Вовк ◽  
О.А. Стребков ◽  
А.А. Волошина ◽  
...  
Keyword(s):  
Energy Saving ◽  
Induction Motors ◽  
Variable Load

scholarly journals Optimization of the Fuel Cell Renewable Hybrid Power System Using the Control Mode of the Required Load Power on the DC Bus

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1889 ◽  
Author(s):  
Nicu Bizon ◽  
Valentin Alexandru Stan ◽  
Angel Ciprian Cormos
Keyword(s):  
Energy Source ◽  
Fuel Cell ◽  
Power System ◽  
Control Mode ◽  
Variable Load ◽  
Hybrid Power System ◽  
Hybrid Power ◽  
Load Power ◽  
Load Demand ◽  
Dc Bus

In this paper, a systematic analysis of seven control topologies is performed, based on three possible control variables of the power generated by the Fuel Cell (FC) system: the reference input of the controller for the FC boost converter, and the two reference inputs used by the air regulator and the fuel regulator. The FC system will generate power based on the Required-Power-Following (RPF) control mode in order to ensure the load demand, operating as the main energy source in an FC hybrid power system. The FC system will operate as a backup energy source in an FC renewable Hybrid Power System (by ensuring the lack of power on the DC bus, which is given by the load power minus the renewable power). Thus, power requested from the batteries’ stack will be almost zero during operation of the FC hybrid power system based on RPF-control mode. If the FC hybrid power system operates with a variable load demand, then the lack or excess of power on the DC bus will be dynamically ensured by the hybrid battery/ultracapacitor energy storage system for a safe transition of the FC system under the RPF-control mode. The RPF-control mode will ensure a fair comparison of the seven control topologies based on the same optimization function to improve the fuel savings. The main objective of this paper is to compare the fuel economy obtained by using each strategy under different load cycles in order to identify which is the best strategy operating across entire loading or the best switching strategy using two strategies: one strategy for high load and the other on the rest of the load range. Based on the preliminary results, the fuel consumption using these best strategies can be reduced by more than 15%, compared to commercial strategies.

scholarly journals Code Calibration of the Eurocodes

2021 ◽  
Vol 11 (12) ◽  
pp. 5474
Author(s):  
Tuomo Poutanen
Keyword(s):  
High Reliability ◽  
High Accuracy ◽  
Variable Load ◽  
Reliability Model ◽  
Safety Factors ◽  
Rounding Errors ◽  
Code Calibration ◽  
Load Factors ◽  
Characteristic Values

This article addresses the process to optimally select safety factors and characteristic values for the Eurocodes. Five amendments to the present codes are proposed: (1) The load factors are fixed, γG = γQ, by making the characteristic load of the variable load changeable, it simplifies the codes and lessens the calculation work. (2) Currently, the characteristic load of the variable load is the same for all variable loads. It creates excess safety and material waste for the variable loads with low variation. This deficiency can be avoided by applying the same amendment as above. (3) Various materials fit with different accuracy in the reliability model. This article explains two options to reduce this difficulty. (4) A method to avoid rounding errors in the safety factors is explained. (5) The current safety factors are usually set by minimizing the reliability indexes regarding the target when the obtained codes include considerable safe and unsafe design cases with the variability ratio (high reliability/low) of about 1.4. The proposed three code models match the target β50 = 3.2 with high accuracy, no unsafe design cases and insignificant safe design cases with the variability ratio 1.07, 1.03 and 1.04.

scholarly journals Generation of terahertz vector beams using dielectric metasurfaces via spin-decoupled phase control

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3393-3402 ◽  
Author(s):  
Yuehong Xu ◽  
Huifang Zhang ◽  
Quan Li ◽  
Xueqian Zhang ◽  
Quan Xu ◽  
...  
Keyword(s):  
High Performance ◽  
Special Kind ◽  
Phase Control ◽  
High Resolution Imaging ◽  
Plasmon Excitation ◽  
Bessel Beams ◽  
Dynamic Phase ◽  
Vector Beams ◽  
Resolution Imaging ◽  
Spatially Variant

AbstractCylindrical vector beams (CVBs), being a special kind of beams with spatially variant states of polarizations, are promising in photonics applications, including high-resolution imaging, plasmon excitation, optical trapping, and laser machining. Recently, generating CVBs using metasurfaces has drawn enormous interest owing to their highly designable, multifunctional, and integratable features. However, related studies remain unexplored in the terahertz regime. Here, a generic method for efficiently generating terahertz CVBs carrying orbital angular momentums (OAMs) is proposed and experimentally demonstrated using transmission-type spatial-variant dielectric metasurfaces, which is realized by designing the interference between the two circularly polarized transmission components. This method is based on spin-decoupled phase control allowed by simultaneously manipulating the dynamic phase and geometric phase of each structure, endowing more degree of freedom in designing the vector beams. Two types of metasurfaces which respectively generate polarization-dependent terahertz vector vortex beams (VVBs) and vector Bessel beams (VBBs) are experimentally characterized. The proposed method opens a new window to generate versatile vector beams, providing new capabilities in developing novel, compact, and high-performance devices applicable to broad electromagnetic spectral regimes.

scholarly journals Maximizing Transfer Efficiency with an Adaptive Wireless Power Transfer System for Variable Load Applications

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1417
Author(s):  
Jung-Hoon Cho ◽  
Byoung-Hee Lee ◽  
Young-Joon Kim
Keyword(s):  
Loading Condition ◽  
Wireless Power Transfer ◽  
Input Voltage ◽  
Transfer Efficiency ◽  
Maximum Efficiency ◽  
Variable Load ◽  
Power Transfer ◽  
Wireless Power ◽  
Variable Loading ◽  
Power Transfer Efficiency

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.

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