56 research outputs found
Communicating about the Middle East respiratory syndrome outbreak to the international community and in-country foreigners, Republic of Korea, 2015
During the Middle East respiratory syndrome (MERS) outbreak in 2015, the Ministry of Health and Welfare (MOHW) of the Republic of Korea provided outbreak information targeting international visitors and foreign residents through multiple channels. The MOHW created a MERS portal website in Korean and English on 10 June 2015; in addition, the existing MOHW website provided English-language press releases beginning 28 May. A toll-free telephone hotline also started service in English on 12 June; it expanded to include 18 other foreign languages on 15 June. This report describes the usage of these multi-language communication channels during this MERS outbreak
A Low-Cost and High-Efficiency Active Cell-Balancing Circuit for the Reuse of EV Batteries
In this paper, a high-efficiency and low-cost active cell-to-cell balancing circuit for the reuse of electric vehicle (EV) batteries is proposed. In the proposed method, a battery string is divided into two legs to transfer the charge from each cell in one leg to that in the other and a bidirectional CLLC resonant converter is used to transfer energy between the selected cells. Thanks to the proposed structure, the number of bidirectional switches and gate drivers can be reduced by half compared to the conventional direct cell-to-cell topologies, thereby achieving lower cost for the system. The CLLC converter is used to transfer the charge, and it is designed to work at resonant frequencies to achieve zero-voltage zero-current switching (ZVZCS) for all the switches and diodes. Consequently, the system’s efficiency can be enhanced, and hence, the fuel economy of the system can also be improved significantly. To verify the performance of the proposed active cell-balancing system, a prototype is implemented for balancing the three EV battery modules that contain twelve lithium-ion batteries from xEV. The maximum efficiency achieved for the charge transfer is 89.4%, and the balancing efficiency is 96.3%
Engaging the international community during the 2015 Middle East respiratory syndrome outbreak in the Republic of Korea
The 2015 Middle East respiratory syndrome (MERS) outbreak in the Republic of Korea, which started with an imported case and spread throughout the country with a total of 186 cases, revealed the vulnerabilities of the health-care system of the country. The situation was compounded by the unique health-care settings in the Republic of Korea, including crowded emergency departments and large numbers of hospital visitors seeking care at multiple hospitals. To assist with the outbreak response, the Ministry of Health and Welfare of the Republic of Korea hosted several international joint missions that provided valuable information and recommendations for MERS control and prevention of future outbreaks. This report briefly summarizes the missions’ outcomes and discusses their positive impacts
Combining finite element and reinforcement learning methods to design superconducting coils of saturated iron-core superconducting fault current limiter in the DC power system
Rtds-based modelling and analysis of grid-connected fixed speed wind generator system
This paper proposes RTDS (Real Time Digital Simulator) based modeling and simulation analysis of grid connected fixed speed wind generator system. A 3MW wind generator system connected to the power grid is modeled by using RSCAD. Then the developed wind generator system in RSCAD program is interfaced with the RTDS in order to carry out simulations in real time. For the purpose of accurate simulation, real wind speed data extracted by an anemometer is used in this work. Through the simulation results, the validity of the developed wind generator system is confirmed
Improvement of wind generator stability by fuzzy logic-controlled SMES
This paper proposes a fuzzy logic-controlled SMES (superconducting magnetic energy storage) scheme for the stabilization of grid connected wind generator system. The control scheme of SMES is based on a sinusoidal PWM (Pulse Width Modulation) voltage source converter (VSC) and a twoquadrant DC-DC chopper using insulated-gate-bipolar-transistor (IGBT). A comparative study is carried out between the proposed fuzzy logic-controlled SMES and fuzzy logic-based pitch controller to improve the wind generator stability. Simulation results demonstrate that the performance of the proposed fuzzy logic-controlled SMES is better than that of the fuzzy logic-based pitch controller in order to stabilize the wind generator
A novel real time simulation method for grid-connected wind generator system by using RTDS
This paper presents a novel real time simulation method of grid connected wind generator system using RTDS (Real Time Digital Simulator). A 3MW wind generator system connected to power grid is modeled by using RSCAD. Then the developed wind generator system in RSCAD program is interfaced with the RTDS in order to carry out simulations in real time. For the purpose of accurate simulation, real wind speed data extracted by anemometer is used in this work. Through the simulation results, the validity of the developed wind generator system is confirmed
Coordination of fuzzy controlled braking resistor and optimal reclosing for damping shaft-torsional oscillations of synchronous generator
This paper proposes the coordination of fuzzy logiccontrolled braking resistor (BR) and optimal reclosing to damp turbine-generator shaft torsional oscillations during unsuccessful reclosing of circuit breakers. The performance of the coordination of fuzzy controlled braking resistor and optimal reclosing is compared to that of the coordination of fuzzy controlled braking resistor and conventional autoreclosing. Simulation results show that the proposed coordination of fuzzy controlled braking resistor and optimal reclosing is more effective than that of the coordination of fuzzy controlled braking resistor and conventional auto-reclosing in damping shaft torsional oscillations during unsuccessful reclosing of circuit breakers
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