• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2148-2153
• /
• 2007

The electricity conversion-efficiency of solar cell for commercial application is about 6-15%. More than 85% of the incoming solar energy is either reflected or absorbed as heat energy. Consequently, the working temperature of the photovoltaic cells increases considerably after prolonged operations and the cell's efficiency drops significantly. PV/T refers to the integration of a PV module and a solar thermal collector in a single piece of equipment. By cooling the PV module with a fluid steam like air or water, the electricity yield can be improved. At the same time, the heat pick-up by the fluid can be to support space heating or service hot-water systems. In this study, a pulsating heat pipe solar heat collector was combined with single-crystal silicon photovoltaic cell in hybrid energy-generating unit that simultaneously produced low temperature heat and heat and electricity. This experiment was investigating thermal and electrical efficiency for evaluation of a PV/T system.

• 한국전기전자재료학회논문지
• /
• 제25권12호
• /
• pp.1021-1027
• /
• 2012

In this paper, multi-string power balancing system for streetlight was developed. Accordingly, the components of the system was developed, unit converters, MPPT control unit, a bank of Li-ion battery and controls the charging and discharging. Loss by improving the efficiency of the system through the parallel operation of the unit converter output will be reduced. And by improving the efficiency of the system through the unit converter parallel operation, output losses will be reduced. Charging and discharging efficiency of the device used in a typical solar streetlight is calculated based on the maximum power input. Because of the variation of the input power has a weakness. In this paper, flexible to changes in the input, and a system was developed to minimize the cost per watt. Measure the performance of the unit module from the system, the result was more than 91%. And the charging capacity 12 V/105 Ah, module power 180 W, respectively. Should expect to be able to improve performance through continuous monitoring in the future.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
• /
• pp.460-463
• /
• 2008

A large part of the overall industrial energy is dissipated as waste heat despite of much development in the utilization of thermal energy. A mean efficiency is reported to be only around 30 to 35%. The existing waste heat recovery technology has reached its limit and consequently, the development of a new technology is necessary. Improving efficiency using thermoelectric technology has recently come into the spotlight because of its unique way to recover thermal energy. In fact, thermoelectric generator directly converts thermal energy into electric energy by a solid state without any moving parts. Futhermore remarkable improvement in the thermoelectric energy conversion efficiency has been achieved. In this study, a thermoelectric generator was made using commercialized thermoelectric modules. With thermoelectric modules attached on a duct surface, hot air was blown into the duct using a hot air blower. On the other side of the module, a water jacket was attached to cool the module. With different air inlet temperatures and water flowrates, the electrical power of the thermoelectric generator was measured.

• 전기학회논문지
• /
• 제56권10호
• /
• pp.1763-1769
• /
• 2007

To improve the cycle-life and efficiency of an energy storage system for HEV, a dynamic control system consisted of a switch between a battery and an ultracapacitor module is proposed, which is appropriate for mild hybrid vehicle with 42V power net. The switch can be controlled based on the status of the battery and the ultracapacitor module, and a control algorithm that could largely decrease the number of high charging current peak is also implemented. Therefore the cycle life of the battery can be improved such that it is suitable for a mild hybrid vehicle with frequent engine start-stop and regenerative-braking. Also, by maximizing the use of the ultracapacitor, the system efficiency during high current charging and discharging operation is improved. Finally, this system has the effects that improves the efficiency of energy storage system and reduces the fuel consumption of a vehicle. To verify the validity of the proposed system, this paper presented cycles test results of different energy storage systems: a simple VRLA battery, hybrid energy Pack (HEP, a VRLA battery in Parallel with Ultracapacitor) and a HEP with a switch that controlled by energy management system (EMS). From the experimental result, it was proved the effectiveness of the algorithm.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
• /
• pp.537-541
• /
• 2004

A high efficiency ZVS PWM asymmetrical half bridge converter for a plasma display panel (PDP) sustaining power module is proposed in this paper. To achieve the ZVS of power switches for the wide fond range, n small additional inductor $L_{lkg}$, which also acts as an output filter inductor, is serially inserted to the transformer primary side. Then, to solve the problem related to ringing in the secondary rectifier caused by $L_{lkg}$, the proposed circuit employs a structure without the output filter inductor, which helps the voltages across rectifier diodes to be clamped at the output voltage. Therefore, no dissipative RC (resistor capacitor) snubber for rectifier diodes is needed and n high efficiency as well as low noise output voltage can be realized. In addition, since it has no large output inductor filter, it features a simpler structure, lower cost, less mass, and lighter weight. Moreover, since all energy stored in $L_{lkg}$ is transferred to the output side, the circulating energy problem can be effectively solved. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385Vdc/170Vdc prototype are presented.

• Journal of Power Electronics
• /
• 제18권2호
• /
• pp.395-406
• /
• 2018

Marine controlled-source electromagnetic transmitters (MCSETs) are important in marine electromagnetic exploration systems. They play a crucial role in the exploration of solid mineral resources, marine oil, and gas and in marine engineering evaluation. A DC-DC controlled-source circuit is typically used in traditional MCSETs, but using this circuit in MCSETs causes several problems, such as large voltage ringing of the high-frequency diode, heating of the insulated-gate bipolar transistor (IGBT) module, high temperature of the high-frequency transformer, loss of the duty cycle, and low transmission efficiency of the controlled-source circuit. This paper presents a clamping-diode circuit for MCSET (CDC-MCSET). Clamping diodes are added to the controlled-source circuit to reduce the loss of the duty ratio and the voltage peak of the high-frequency diode. The temperature of the high-frequency diode, IGBT module, and transformer is decreased, and the service life of these devices is prolonged. The power transmission efficiency of the controlled-source circuit is also improved. Saber simulation and a 20 KW MCSET are used to verify the correctness and effectiveness of the proposed CDC-MCSET.

• 한국태양에너지학회 논문집
• /
• 제36권5호
• /
• pp.19-30
• /
• 2016

In this study, realize voltage regulation $220Vac{\pm}10%$ or less, frequency fluctuation $60Hz{\pm}1%$ or less over the independent operation and grid-connected operation technologies for power stabilization relates to the ESS designed and manufactured in conjunction with solar installations and solar to compensate the output reduction due to the polarization of the solar module through the polarization prevention technology for preventing the optical module efficiency is lowered, in conjunction with the BMS inverter efficiency was more than 92%, more than 90% of the charging efficiency to the target. This study was designed in conjunction with the ESS solar power plants, grid-connected operation and independent operation, Peak-Cut, it can stabilize the grid via the Peak-Shifting operation

• 한국전기전자재료학회논문지
• /
• 제29권12호
• /
• pp.819-823
• /
• 2016

DSSC (dye-sensitized solar cell) is expected to be one of the next-generation photovoltaics because of its environment-friendly and low-cost properties. However, commercialization of DSSC is difficult because of the electrolyte leakage. We propose thermal curable base on silicon resin and apply a unit cell and large area ($200{\times}200mm$) dye-sensitized solar cell. The resin aimed at sealing of DSSC and gives a promising resolution for sealing of practical DSSC. In result, the photoelectric conversion efficiency of the unit cell and the module was 6.63% and 5.49%, respectively. In the durability test result, the photoelectric conversion efficiency of the module during 500, 1,000, 1,500 and 2,000 hours was 0.73%, 0.73%, 1.82% and 2.36% respectively. It was confirmed that the photoelectric conversion efficiency characteristics are constant. We have developed encapsulation material of thermal curing method excellent in chemical resistance. A sealing material was applied to the dye-sensitized solar cell and it solved the problem of durability the dye-sensitized solar cell. Sealing material may be applied to verify the possibility of practical application of the dye-sensitized solar cell.

• Journal of Power Electronics
• /
• 제6권1호
• /
• pp.45-51
• /
• 2006

A new high efficiency phase shifted full bridge (PSFB) converter for the power sustaining module of a plasma display panel (PDP) is proposed in this paper. The proposed converter employs a voltage doubler rectifier without an output inductor. Since it has no output inductor, the voltage stresses of the secondary rectifier diodes can be clamped at the output voltage level. No dissipative resistor-capacitor (RC) snubber for rectifier diodes is needed. Therefore, high efficiency, as well as, a low noise output voltage can be realized. Due to the elimination of the large output inductor, it features a simple structure, lower cost, smaller mass and lighter weight. Furthermore, the proposed converter has wide zero voltage switching (ZVS) ranges with low current stresses of the primary switches. Also the resonance between the leakage inductor of the transformer and the capacitor of the voltage doubler cell reduces the current stresses of the rectifier diodes. In this paper, operational principles, an analysis of the proposed converter and experimental results are presented.

• Journal of Power Electronics
• /
• 제1권2호
• /
• pp.78-87
• /
• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.