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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of the Korean Institute of Power Electronics
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Journal DOI :
The Korean Institute of Power Electronics
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Volume & Issues
Volume 15, Issue 6 - Dec 2010
Volume 15, Issue 5 - Oct 2010
Volume 15, Issue 4 - Aug 2010
Volume 15, Issue 3 - Jun 2010
Volume 15, Issue 2 - Apr 2010
Volume 15, Issue 1 - Feb 2010
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Technology and Development Trend of High Efficiency and High Power Density Server Power System
Cho, Kyu-Min ; Kim, Young-Do ; Moon, Gun-Woo ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 87~95
DOI : 10.6113/TKPE.2010.15.2.87
As the information oriented society is developing, computer is one of the necessities in our daily life. Especially, the client-server system based on internet is widely used due to the enormous amounts of data and the increasing awareness of the data security. Under these circumstances, the market of the server computer with the $57 billion global market is increasing steadily regardless of economic conditions. However, the domestic server market entirely depends on overseas companies with high technical skills and production power. Therefore, we investigates technology and development trends of the server power system to assist domestic companies in entering the global server power system market in this special paper.
Hold up Time Extension Technique for high efficiency, high power density server power supply
Kim, Young-Do ; Cho, Kyu-Min ; Moon, Gun-Woo ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 96~102
DOI : 10.6113/TKPE.2010.15.2.96
Nowadays, climate change becomes serious problem in all around country. Especially because of global warming problem, every country is suffered from various natural disasters. To prevent these changes, every industry are keep requiring the increase in energy efficiency. Recently, in the regulation of CSCI (climate savers computing initiate), the efficiency of server power supply should meet the demand of 94% at 50% load condition by 2010, which is called platinum level. Hence, server power system has been dramatically developed with the various technique for the high efficiency of it. Among those technique, hold up time extension technique has received wide attention and has been researched for a long time. In this paper, technical trend of hold up time extension circuit will be covered for the high efficiency, high power density server power supply.
A New Mode Changable Asymmetric Full Bridge DC/DC Converter having 0 ~ 100 % Duty Ratio
Shin, Yong-Saeng ; Roh, Chung-Wook ; Hong, Sung-Soo ; Han, Sang-Kyoo ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 103~110
DOI : 10.6113/TKPE.2010.15.2.103
In this paper, a new mode changeable asymmetric full bridge dc/dc converter is proposed to solve the freewheeling current problem of the conventional zero voltage switching(ZVS) phase shift full bridge(PSFB) dc/dc converter of low output voltage and high output current applications. The proposed converter is operated as an asymmetric full bridge converter when the duty cycle is less than 50% and active clamp full bridge converter when the duty cycle is greater than 50%. As a result, since its freewheeling current is eliminated, the conduction loss is lower than that of the conventional ZVS PSFB dc/dc converter. Moreover, ZVS of all power switches can be ensured along a wide load ranges and output current ripple is very small. Therefore, high efficiency of the proposed converter can be achieved. Especially since its operation mode is changed to the active clamp full bridge converter during hold up time and can be operated with 50~100% duty ratio, it can produce the stable output voltage along wide input voltage range. The operational principles, theoretical analysis and design considerations are presented. To confirm the operation, validity and features of the proposed converter, experimental results from a 1.2kW(
) prototype are presented.
A New Current-Balancing Multi-Channel LED Driver for a Large Screen LCD Backlight Unit
Lee, Sang-Hyun ; Cho, Sang-Ho ; Roh, Chung-Wook ; Hong, Sung-Soo ; Han, Sang-Kyoo ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 111~118
DOI : 10.6113/TKPE.2010.15.2.111
Recently, LCD TV using LED backlight has a great attention due to its low power consumption, slim construction, mercury free, wide color gamut and fast response. For the uniform brightness of the LCD panel, multi channel LEDs and DC/DC converter for each LED are required in conventional system. Therefore energy conversion efficiency is poor, the system size bulky and the cost of production high. To overcome these above mentioned drawbacks, a new current-balancing multi-channel LED driver is proposed in this paper. It can not only drive multi-channel LEDs with one DC/DC converter but also provide all LEDs with constant balanced current. To confirm the validity of the proposed driver, its operation and performance are verified on a prototype for 46" LCD TV.
Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter
Li, Xin-Lan ; Shin, Yong-Hwan ; Won, Jae-Sun ; Kim, Jong-Sun ; Shin, Hwi-Beom ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 119~126
DOI : 10.6113/TKPE.2010.15.2.119
An integrated magnetic (IM) transformer is proposed for a phase shifted full bridge (PSFB) converter with zero voltage switching (ZVS). In a proposed IM transformer, the transformer is located on the center leg of E-core and the output inductor is wound on two outer legs with air gap. The proposed IM transformer is analyzed by using the magnetic capacitor model. For reducing the core size, EE core is redesigned. The proposed IM transformer is experimentally verified on a 1.2 kW prototype converter. The converter efficiency with the proposed IM transformer is about 93 % at full load and its volume size can be reduced. It can be expected that the power density can be largely increased with the proposed IM transformer.
Development Of High Efficiency Boost DC/DC Converter For EV
Choi, Mi-Seon ; Song, Sung-Geun ; Park, Sung-Jun ; Kim, Dae-Kyong ; Kim, Yong-Gu ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 127~133
DOI : 10.6113/TKPE.2010.15.2.127
In the paper, reactorless high efficiency boost DC/DC converter for EV is proposed. In proposed converter, improves efficiency because decrease power loss when the switches are turned on/off using zero current switching (ZCS) at all switch of primary full bridge. By replacing reactance ingredients of L-C resonance circuit for ZCS with leakage inductance ingredients of high frequency transformer, it reduces system size and expense because of not add special reactor. For validity verification of proposed converter, in the paper implements simulation using PSIM and perform experiment by making 5KW DC/DC converter. In experimental results, efficiency of proposed converter conformed superiority.
Development of the Control Algorithm for the Small PEM Fuel Cell Stack
Kim, Tae-Hoon ; Choi, Woo-Jin ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 134~141
DOI : 10.6113/TKPE.2010.15.2.134
Small PEM (Proton Exchange Membrane) fuel cell systems do not require humidification and have great commercialization possibilities. However, methods for controlling small PEM fuel cell stacks have not been clearly established. In this paper, a control method for small PEM fuel cell systems using a dual closed loop with a static feedforward structure is defined and realized using a DSP (Digital Signal Processor). The fundamental elements that need to be controlled in fuel cell systems include the supply of air and hydrogen, water management inside the stack, and heat management of the stack. For small PEM fuel cell stacks operated without a separate humidifier, fans are essential for air supply, heat management, and water management of the stack. A purge valve discharges surplus water from the stack. The proposed method controls the fan using double control loops to quicken transient response of the fan thereby improving the supply rate of air. Feedback control to compensate for the voltage change in fuel cell stack improves the response characteristics in fuel cell to load variations. The feasibility of proposed method was proved by the experiments with a 60W small PEM fuel cell system and operation of a notebook computer using this system.
Maximum Torque per Ampere Control of Interior Permanent Magnet Synchronous Motor based on Signal Injection
Kim, Sung-Min ; Sul, Seung-Ki ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 142~149
DOI : 10.6113/TKPE.2010.15.2.142
Interior Permanent Magnet Synchronous Motor(IPMSM) have gained an increasing popularity in recent years for a variety of industrial applications, because of their high power density, high efficiency and possibility of flux weakening operation. Because the efficiency of IPMSM is one of the important performance characteristic, the Maximum Torque Per Ampere(MTPA) operating method has been indispensible. In theory, MTPA operating point can be calculated using the exact values of the machine parameters. However, the values of the IPMSM parameters are known to vary widely according to the operating condition. Therefore, to operate the IPMSM in the MTPA operating point, the machine parameters should be estimated in real-time. In this paper, the new MTPA operating method based on the signal injection is presented. By injecting the high frequency current signal, the MTPA operating criteria can be calculated by measuring the input power to IPMSM. The proposed method can find the MTPA operating point with simple signal processing regardless of the parameter variation.
Operation Analysis of Resonant DC/DC Converter able to Harvest Thermoelectric Energy
Kim, Hyeok-Jin ; Chung, Gyo-Bum ; Cho, Kwan-Youl ; Choi, Jae-Ho ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 150~158
DOI : 10.6113/TKPE.2010.15.2.150
The operational characteristics of a resonant DC/DC converter, which can harvest thermoelectric energy, is analyzed, depending on the relative magnitudes of the input voltage and the load voltage. The resonant converter consists of LC resonant circuit connected to DC input source and a resonant pulse converter in which the input energy is transferred to the load as the resonant capacitor voltage is peak. The resonant capacitor doubles the input voltage by the resonance phenomenon. By the relative magnitude between the input voltage and the output voltage, the resonant DC/DC converter operates in three different modes. For boost mode, the peak voltage of the resonant capacitor is smaller than the load voltage. For hybrid mode, the peak voltage of the resonant capacitor is bigger than the load voltage and every switching period has both the boost mode and the direct mode. For the direct mode, the input voltage is bigger than the load voltage and the converter transfers directly the input energy to the load without the switching operation. Operation principles and the feasibility of the converter for the thermoelectric energy harvesting are verified with PSPICE simulation and experiment.
Predictive Current Control of a Grid-Connected Inverter with Grid Voltage Observer
Lee, Kui-Jun ; Hyun, Dong-Seok ;
The Transactions of the Korean Institute of Power Electronics, volume 15, issue 2, 2010, Pages 159~166
DOI : 10.6113/TKPE.2010.15.2.159
For a grid-connected inverter in distributed generation systems, the current control is essential, and recently, the predictive current control based on a high performance digital signal processors (DSP) to satisfy a fast dynamic response has been widely investigated. However, the performance of predictive current control is degraded by the time delay due to digital implementation, the parameter and measured value errors and the interference of noise, and also theses make system even unstable. Therefore, this paper proposes the predictive current control using grid voltage observer for grid-connected inverter applications. To determine the relevant voltage observer gain, the low-order harmonics of grid voltage are considered, and the effect of filter parameter errors is analyzed. The proposed method has a fast current response capability, the robustness to noise and simple implementation due to voltage sensorless control and the robust current control performance to low-order grid harmonics. The feasibility of the proposed method is verified by simulation and experimental results.