An efficiency droop in GaN-based light-emitting diodes (LED) was characterized by examining its general thermophysical parameters. An effective suppression of emission degradation afforded by the introduction of InGaN/GaN heterobarrier structures in...
Efficiency droop in GaN-based light emitting diodes (LEDs) under high injection current density perplexes the development of high-power solid-state lighting. Although the relevant study has lasted for about 10 years, its mechanism is still not thorou...
The effect of strongly-imbalanced carrier concentration and mobility on efficiency droop is studied by comparing the onset voltage of high injection, the onset current density of the droop, and the magnitude of the droop, as well as their temperature...
We compared the efficiency droop of InGaN multiple-quantum-well (MQW) blue light-emitting diode (LED) structures grown on silicon(111) and c-plane sapphire substrates and analyzed the efficiency droop characteristics using the rate equation model wit...
In this study, wavelength-dependent efficiency droop phenomena in InGaN-based light-emitting diodes (LEDs) by a reduced effective active region volume were investigated. Different effective active region volumes can be extracted from theoretical fitt...
This paper reports an AlGaN-based ultraviolet-B light-emitting diode (UVB-LED) with a peak wavelength at 293 nm that was almost free of efficiency droop in the temperature range from 298 to 358 K. Its maximum external quantum efficiencies (EQEs), whi...
Carrier recombination behavior in c-plane GaN-based laser diodes (LDs) is numerically investigated by using the commercial software LASTIP. It is found that efficiency droop phenomenon does exist in GaN-based LDs before lasing, which is confirmed by...
In this study, GaN-based blue InGaN/GaN light-emitting diodes (LEDs) with different growth rates of the quantum barriers were fabricated and investigated. The LEDs with quantum barriers grown with a higher growth rate exhibit a lower leakage current...
We demonstrate an ultra-low efficiency droop in c-plane polar InGaN blue light-emitting diodes (LEDs) by reducing the carrier density using a wide InGaN last quantum well (LQW). It is found that the LEDs with a 5.2 nm thick LQW show a negligible effi...
In this study, we found that the current droop (J-droop) in AlGaN-based UVB light-emitting diodes was more obvious at higher temperatures, despite both the main and parasitic peaks undergoing monotonic decreases in their intensity upon an increase in...
We investigated the efficiency droop phenomenon in blue and green GaN-based light-emitting diodes (LEDs) and laser diodes (LDs), which poses a significant challenge in high-power LEDs and is characterized by a reduction in external quantum efficiency...
Modern deep neural network (DNN) accelerators must sustain high throughput while avoiding performance degradation from supply voltage (VDD) droop, which occurs when large arrays of multiply–accumulate (MAC) units switch concurrently and induce...
We study recombination processes in nitride LEDs emitting from 270 to 540 nm with EQE ranging from 4% to 70%. We found a significant correlation between the LEDs’ electro-optical properties and the degree of nanomaterial disorder (DND) in quant...
The serious separation of electron–hole wavefunctions, which is caused by the built-in electric field, prevents electron–hole radiative recombination in quantum wells (QWs) in high-In-content InGaN-based red light-emitting diodes (LEDs)....
A novel Multi-Quantum-Well Deep Ultra Violet Light Emitting Diode (DUV-LED) device with a near-pole hole insertion layer and far-pole hole insertion layer was proposed and carefully studied. It was found that remarkable enhancements both in the light...
This paper addresses the challenges of efficient electric vehicle (EV) charging integration in Direct Current (DC) microgrids (MGs), particularly the impact of intermittent EV loads on power sharing and voltage regulation. Traditional droop control m...
In this study, we compared the device performance of GaInN-based green LEDs grown on c-plane sapphire substrates with a conventional low temperature GaN buffer layer to those with a sputtered-AlN buffer layer. The light output power and leakage curre...
Light-emitting diodes (LEDs) based on Gallium Nitride (GaN) have been revolutionizing various applications in lighting, displays, biotechnology, and other fields. However, their energy efficiency is still below expectations in many cases. An unpreced...
Silicon carbide (SiC) three-phase converters are widely adopted in parallel power distribution systems for their high efficiency, yet their performance is challenged by high switching frequency and communication constraints. For the parallel inverter...
This paper introduces the Exponent Droop Function (EDF), a nonlinear grid-forming (GFM) control paradigm that enhances the flexibility and performance of droop-based control in microgrids. Unlike conventional droop mechanisms, the EDF establishes a g...
The interline power flow controller (IPFC) presents a promising solution for managing the directional and quantitative interaction of power between different lines, facilitating a significant improvement in power system stability. Based on such a bac...
High-voltage direct current (HVDC) systems, with their advantages of large capacity, long distance, high efficiency, and low loss, are becoming the core support of new power systems. However, in conventional droop control, the fixed droop coefficient...
Converter-based generators (CBGs) that use renewable energy sources (RESs) are replacing traditional aging coal and nuclear power generators. Increasing the penetration of CBGs into the entire power generation process reduces both the inertia constan...
In order to achieve the flexible and efficient utilization of distributed energy resources, microgrids (MGs) can enhance the self-healing capability of distribution systems. Conventional primary droop control in microgrids exhibits deviations in volt...
Due to the mismatch of line impedance, the traditional droop control of parallel inverters in microgrids has limitations. It is difficult to achieve uniform distribution of reactive power and reduce voltage deviation. This paper proposes a droop cont...
The emergence of highly efficient and cost-effective power converters, coupled with the growing diversity of DC loads, has elevated the importance of DC microgrids to a level comparable with AC microgrids in the modern power industry. DC microgrids a...
This paper presents a new control strategy for isolated micro-grids including wind turbines (WT), fuel cells (FC), photo-voltaic (PV) and battery energy storage systems (BESS). FC have been used in parallel with BESSs in order to increase their lifet...
A DC microgrid is an efficient way to combine diverse sources; conventional droop control is unable to achieve both accurate current sharing and required voltage regulation. This paper provides a new adaptive control approach for DC microgrid applica...
Highly efficient indium gallium nitride (InGaN)-based yellow light-emitting diodes (LEDs) with low efficiency droop have always been pursued for next-generation displays and lighting products. In this work, we report an InGaN quantum barrier (QB) wit...
The AC power system is leading due to its established standards. The depleting thread of fossil fuels, the significant increase in cost and the alarming environmental situation raises concerns. An Islanded DC microgrid, due to its novel characteristi...
This article aims to develop a smart isolated energy community (EC) by coupling the neighbouring rural community microgrids (CMGs) with enhanced droop control for efficient power sharing. This recommended solution employs a power management (PM) base...
The differences in spatially optical properties between blue and green quantum wells (QWs) in a monolithic dual-wavelength semipolar (20-21) structure were investigated by scanning near-field optical microscopy (SNOM). The shortest wavelength for gre...
The phase circulating current (PCC) of the parallel three-phase inverter systems dramatically affects the power quality and conversion efficiency of the power grid. In this paper, a composite suppression strategy is proposed to solve the PCC issue by...
The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by...
The increase in demand for clean, safe, and environmentally friendly renewable energy sources faces several challenges such as system design and reliable operations. DC microgrid (MG) is a promising system due to higher efficiency and natural interfa...
Ancillary frequency controllers such as droop controllers are beneficial for frequency regulation of a microgrid with high penetration of wind generators. However, the use of such ancillary frequency controllers may cause torsional oscillation in the...
Managing parallel−connected single−phase distributed generators in low−voltage microgrids is challenging due to the volatility of renewable energy sources and fluctuating load demands. Traditional droop control struggles to maintain...
The paper presents a new maximum power point tracking (MPPT) method for photovoltaic (PV) battery chargers. It consists of adding a low frequency modulation to the duty-cycle and then multiplying the ac components of the panel voltage and power. The...
Provision of an efficient water supply system (WSS) is one of the top priorities of all municipals to ascertain adequate water supply to the city. Intake is the lifeline of the water supply system and largely effects the overall plant efficiency. The...
This study introduces novel stochastic distributed cooperative control (SDCC) in the context of island microgrids (MGs). A proportional resonant (PR) controller and virtual impedance droop control in stationary reference frames are employed in cooper...
Joining of pure copper C1100 and aluminum alloy A6061-T6 plates of 5 mm thickness was investigated. The method was developed by one of the authors, in which the newly created surfaces of a pair of plates obtained by high-speed shear were immediately...
Bidirectional energy storage inverters serve as crucial devices connecting distributed energy resources within microgrids to external large-scale power grids. Due to the disruptive impacts arising during the transition between grid-connected and isla...
Renewable-based sources can be interconnected through power electronic converters and connected with local loads and energy storage devices to form a microgrid. Nowadays, DC microgrids are gaining more popularity due to their higher efficiency and re...
This paper proposes a bidirectional boost–buck converter employing a six-pack SiC intelligent power module using droop control in DC nano-grids. The topology is constructed as a cascaded structure of an interleaved boost converter and buck conv...
The microgrid has two main steady-state modes: grid-connected mode and islanded mode. The microgrid needs a high-performance controller to reduce the overshoot value that affects the efficiency of the network. However, the high voltage value causes t...
Models describing the tunneling of electrons and holes through parabolic InxGa1−xN/GaN quantum well/LED structures with respect to strain were developed. The transmission coefficient, tunneling lifetime, and efficiency of LED structures were evaluate...
The missions of modern aircraft require multiple abilities, such as highly efficient taking-off and landing, fast arrival, and long-endurance hovering. It is difficult to achieve all technical objectives using traditional aircraft design technology....
The increase in the use of converter-interfaced generators (CIGs) in today’s electrical grids will require these generators both to supply power and participate in voltage control and provision of grid stability. At the same time, new possibili...
Floating photovoltaic (FPV) power generation technology has gained widespread attention due to its advantages, which include the lack of the need to occupy land resources, low risk of power limitations, high power generation efficiency, reduced water...
Droop-controlled inverters, which are the main interfaces between distributed generators (DGs) and grid AC bus, are widely adopted in today’s microgrids. Because the DGs are usually dispersed along with the microgrids, which may spread out in a...
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