• Journal of Korea Multimedia Society
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• v.25 no.11
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• pp.1572-1581
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• 2022

Energy conversion to renewable energy is being promoted to solve the recently serious environmental pollution problem. Solar energy is one of the promising natural renewable energy sources. Compared to other energy sources, it is receiving great attention because it has less ecological impact and is sustainable. It is important to predict power generation at a future time in order to maximize the output of solar energy and ensure the stability and variability of power. In this paper, solar power generation data and sensor data were used. Using the PCC(Pearson Correlation Coefficient) analysis method, factors with a large correlation with power generation were derived and applied to the GAM(Generalized Additive Model). And the prediction accuracy of the power generation prediction model was judged. It aims to derive efficient solar power generation in the future and improve power generation performance.

• Journal of the Korean Electrochemical Society
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• v.26 no.2
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• pp.19-34
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• 2023

Due to the intermittency of renewable energy sources, a need to store and transport energy will increase. Hydrogen production through water electrolysis will provide an excellent way to supplement the intermittency of renewable energy sources. While alkaline water electrolysis is currently the most mature technology, it has drawbacks of low current density, large footprint, gas crossover, etc. The PEM water electrolysis has potential to replace the alkaline electrolysis. However, expensive catalyst material used in the PEM electrolysis has been the bottleneck of widespread use. In this review, we have reviewed recent efforts to reduce catalyst loading in PEM water electrolysis. In core-shell nanostructures, the precious metal catalyst forms a shell while heteroatoms form a core. In this way, the catalyst loading can be significantly reduced while maintaining the catalytic activity. In another approach, a corrosion-resistant support is utilized, which provides a stable platform to impregnate precious metal catalyst.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1367-1379
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• 2015

A hybrid HVDC system that is composed of line commutated converter (LCC) at the rectifier side and voltage source converter (VSC) in series with LCC at the inverter side is studied in this paper. The start-up strategy, DC fault ride-through capability, and fault recovery strategy for the hybrid HVDC system are proposed. The steady state and dynamic performances under start-up, AC fault, and DC fault scenarios are analyzed based on a bipolar hybrid HVDC system. Furthermore, the immunity of the LCC inverter in hybrid HVDC to commutation failure is investigated. The simulation results in PSCAD/EMTDC show that the hybrid HVDC system exhibits favorable steady state and dynamic performances, in particular, low susceptibility to commutation failure, excellent DC fault ride-through, and fast fault recovery capability. Results also indicate that the hybrid HVDC system can be a good alternative for large-capacity power transmission over a long distance byoverhead line.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1111-1126
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• 2018

In modern power systems, distributed generators (DGs) result in high stress on system frequency stability. Apart from the intermittent nature of DGs, most DGs do not contribute inertia or damping to systems. As a result, a new control method referred to as a virtual synchronous machine (VSM) has been proposed, which brought new characteristics to inverters such as synchronous machines (SM). DGs employing an energy storage system (ESS) provide inertia and damping through VSM control. Meanwhile, energy storage presents some physical constraints in the VSM implementation level. In this paper, a VSM mathematical model is built and analyzed. The dynamic responses of the output active power are presented when a step change in the frequency occurs. The influences of the inertia constant, damping factor and operating point on the ESS volume margins are investigated. In addition, physical constraints are proposed based on these analyses. The proposed physical constraints are simulated using PSCAD/EMTDC software and tested through RTDS experiment. Both simulation and RTDS test results verify the analysis.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1479-1488
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• 2018

Power packet (PP) distribution system distributes power to different loads that share the same distribution cable in a packetized form. When compared with conventional power systems, a PP distribution system (PPDS) can reduce standby power, eliminate Point-of-Load (PoL) power conversion, and intelligently control the load demand from the source side. Due to the absence of PoL conversion, when multiple power sources at different voltage levels and conditioning requirements jointly send power to various loads at different voltage ratings, the generated voltage has an irregular shape. A large filter at each of the load sides is required to reduce such a large voltage ripple. In this paper, a single-inductor, multiple-input-single-output converter structure based multiple-energy-source mixer is proposed. It combines PP generation, maximum power point tracking (MPPT) of renewable energy sources (RESs) and filtering at the source side. To demonstrate the possible renewable energy integration, a PV panel is used as a power source together with other constant voltage sources. The PV power is approximately tracked using the constant voltage method and it is used for each of the PP generations. The proposed PP distribution system is experimentally verified and it is shown that a conventional PI controller is sufficient for stable system operation.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1698-1705
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• 2016

In this paper, a hardware-in-the-loop simulation platform for MMCs is established, which connects a real time digital simulator (RTDS) and a designed MMC controller with optical fiber. In this platform, the converter valves are simulated with a small time step of 2.5 microsecond in the RTDS, and multicore technology is implemented for the controller so that the parallel valve control is distributed between different cores. Therefore, the designed controller can satisfy the requirements of real-time control. The functions of the designed platform and the rationality for the designed controller are verified through experimental tests. The results show that different modulation modes and various control strategies can be implemented in the simulation platform and that each control objective can been tracked accurately and with a fast dynamic response.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.140-140
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• 2011

Korea's RPS, which requires that power generation companies obtain a minimum percentage of their generation by using renewable energy, will take effect in 2012. Based on the first-year law enforcement, generation companies have to satisfy 2% of RPS compliance ratio in 2012. Then, the required RPS compliance ratio will increase up to 10% in 2022. Thus generation companies need to construct power plants that utilize various types of renewable energy sources such as PV and wind power. This work is aimed to analyze the cost of such a renewable power source in terms of capital cost, capacity factor, and fuel cost. We provide the analytical expectation on the renewable power generation cost of 2012 focusing on PV, onshore/offshore wind, fuel cell, and IGCC, which are focused by government policy.

• Journal of the Korean Professional Engineers Association
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• v.39 no.5 s.188
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• pp.20-24
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• 2006

The energy of 97% consumed by our country depends on it's import from foreign market. This article covers hydrogen, fuel-cell, coal liquefaction gasification energy, and solar, wind, photovoltaic, hydro power, ocean, waste, geothermal, bio energy that is renewable energy, and so on, which are new-generation energy sources, increasing the concern on new & renewable source of enenrgy in future.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.608-609
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• 2008

Photovoltaics and wind energy sources are being increased recognised as cost effective generation sources in small isolated power systems(SIPS) primarily supplied by costly diesel fuel. Deterministic and probabilistic techniques are combined using a system well-being approach to provide useful reliability indices for SIPS containing renewable energy. An evaluation of the contribution from photovoltaics and wind energy sources to SIPS reliability is presented. The practicality and effectiveness of the methodology is illustrated by a case study.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.741-748
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• 2022

Policy literacy plays a critical role in enhancing deliberative communication among the public, policymakers, and experts. It also helps develop a positive view of policy by the public, which facilitates public acceptance. Despite its importance, however, policy literacy has received little attention in energy policy practice. Therefore, this study explores factors affecting the public's understanding and knowledge (i.e., policy literacy) of nuclear and new-renewable energy policies. Accordingly, we analyzed data from an online survey of 790 laypeople in Korea. Specifically, we examined the effects of trust, transparency, and policy public relations (PR) on the policy literacy of the public regarding the two alternative energy sources. The analysis revealed that people showed higher policy literacy about the alternative sources when provided with more transparent information and exposed to more policy PR activities. However, we found that trust in energy plant operators played a negligible role in improving policy literacy for both energy sources. Based on these findings, we developed some policy suggestions to secure the energy policy literacy of the public.