• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1110-1111
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• 2008

The life time of PV module is semi-permanent. But, because of installation and module fabrication process, its important part can not be finished. In this paper, we analyze 15 years old modules made from different company. Among the PV modules, the maximum power drop ratio was 12.23% minimum and 80.63% maximum. Also the effect of solar cell's short circuit current difference was analyzed. The PV module exposed about 65days, its the maximum power drop ratio was 1.29% minimum and 23.43% maximum. It is for reduction of current value. And the reason for current reduction was due to reduction of parallel resistance of solar cell. To prevent early degradation, it is need to have attention to fabrication, installation and maintenance.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.197-202
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• 2007

In this study, the cooling characteristics of a liquid cooler using thermoelectric module was experimentally investigated. The experiment was conducted for various inner structures of liquid cooler (4 cases), hot fluid flow rates (0.15-0.25 L/min), number of T.E module (2, 4, 6 set), and the cooling water flow rates (200-600 cc/min) for both parallel and counter flow types. Among the results, better cooling performance geometry was selected. And experiment was also carried out to examine further enhancement of cooling performance by inserting coils (pitches: 0.2, 3, 6 mm) into the hot-fluid channel. Present results showed that the short serpentine type(case2) indicated the best cooling performance. In the case of coil pitch of 3 mm, the best cooling performance was shown, more than 10% increase of the inlet and outlet temperature difference, compared with the case of the cooler without coil. Consequently, the inserted coil pitch should be properly selected to improve cooling performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.328-330
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• 2001

The construct of photovoltaic module array, main power source of photovoltaic system, is very important to the efficiency improvement of whole photovoltaic system. Photovoltaic modules are usually connected in series or parallel to meet power capacity required. Since output characteristics of a photovoltaic module are greatly fluctuated on the variation of insolation, temperature and its type, the maximum open circuit voltage and output operating voltage of photovoltaic module array must exist in the admissible input voltage range of inverter system under any operating conditions. In this paper, we present the selection and array method of photovoltaic modules through simulation for the coupling loss reduction between photovoltaic modules and a inverter.

• Journal of Power Electronics
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• 제14권1호
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• pp.22-29
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• 2014

Current sharing between modules in a converter parallel operation is very important for the reliability of the system. This paper proposes an improved droop method that can effectively improve current sharing accuracy. The proposed method adaptively adjusts the output voltage set-point of each module according to the current set-points. Unlike conventional droop control, modules share a signal line to communicate with each other. Nevertheless, since signals are simple and in digital form, the complexity of the circuitry is much less and noise immunity is much better than those of conventional methods utilizing communication. The operation principle and design procedure of the proposed method are described in detail. Results of the experiment on two boost converters operating in parallel under the specification of a TFT LCD TV panel power supply verify the validity of the proposed scheme.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.289-289
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• 2010

Translation Characteristics of Digital Decoder utilizing the analog parallel processing circuit technology is designed. The fast parallel viterbi decoder system acted by a replacement of the conventional digital viterbi Decoder has good propagation. we are applied proposed analog viterbi decoder to decode PR signal for DVD and analyze the specific circuit and signal characteristics.

• 한국전기전자재료학회논문지
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• 제31권5호
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• pp.290-294
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• 2018

The shingled photovoltaic module can be produced by joining divided solar cells into a string of busbarless structure and arranging them in series and parallel to produce a module, in order to produce a high output per unit area. This paper reports a study to optimize solar cell electrode structure for shingled photovoltaic module fabrication. The characteristics of each electrode structure were analyzed according to the simulation program as follow: 80.62% fill factor in the six-junction solar cell electrode structure and 19.23% efficiency in the five-junction electrode structure. Therefore, the split electrode structure optimized for high-density and high-output shingled module fabrication is the five-junction solar cell electrode structure.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1519-1528
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• 2017

The paper proposes a well structured, component count waned single phase multilevel inverter (MLI) topology, which drives three different modules viz. Stipulation Based Sources Insertion (SBSI) module, Level Count Increasing (LCI) module and Inter-Linking H-Bridge (ILHB) module. The SBSI module confronts the number of basic sources needed in series/parallel to achieve required magnitude for any particular level. The LCI possesses an offsetting dc source and opuses to increase the number of levels and the ILHB module links the SBSI and LCI modules. A developed Hybrid Pulse Width Modulation (HPWM) strategy has PWM pulses for the switches of LCI module while the switches of the remaining two modules function at fundamental switching frequency. A fifteen level version of the proposed stipulation based sources insertion MLI (SBSIMLI) topology is simulated in MATLAB R2010a and a prototype of the similar specifications is constructed to validate the performance by experimental results. The comparison between the developed SBSIMLI topology and the competent topologies shows many interesting facts.

• 유공압시스템학회논문집
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• 제5권4호
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• pp.1-9
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• 2008

In this paper, an energy regeneration algorithm is proposed to make the maximum use of the regenerative braking energy for a parallel hybrid electric vehicle(HEV) equipped with a continuous variable transmission(CVT). The regenerative algorithm is developed by considering the battery state of charge(SOC), vehicle velocity and motor capacity. The hydraulic module consists of a reducing valve and a power unit to supply the front wheel brake pressure according to the control algorithm. In order to evaluate the performance of the regenerative braking algorithm and the hydraulic module, a hardware-in-the-loop simulation (HILS) is performed. In the HILS system, the brake system consists of four wheel brakes and the hydraulic module. Dynamic characteristics of the HEV are simulated using an HEV simulator. In the HEV simulator, each element of the HEV powertrain such as internal combustion engine, motor, battery and CVT is modelled using MATLAB/$Simulink^{(R)}$. In the HILS, a driver operates the brake pedal with his or her foot while the vehicle speed is displayed on the monitor in real time. It is found from the HILS that the regenerative braking algorithm and the hydraulic module suggested in this paper provide a satisfactory braking performance in tracking the driving schedule and maintaining the battery state of charge.

• 대한기계학회논문집B
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• 제28권7호
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• pp.780-788
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• 2004

This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. The fluids are locally accelerated by a flexible PZT fan which deflects inside a fluid transport system of comparatively simple structure mounted on a PCB in a parallel-plate channel(450${\times}$80${\times}$700㎣). Input voltages of 20-100V and a resonance frequency of 23㎐ were used to vibrate the cooling fan. Input power to the module was 4W. The fluid flow around the module was visualized by using PIV system. The temperature distributions around a heated module were visualized by using liquid crystal film(LCF). The cooling effect using a PZT fan was independent of the vent area ratios at the channel inlet and was similar to the forced convection cooling. We found that the flow type was Y-shape and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.2846-2866
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• 2022

Caenorhabditis elegans exhibits sophisticated chemotaxis behavior through two parallel strategies, klinokinesis and klinotaxis, executed entirely by a small nervous circuit. It is therefore suitable for inspiring fast and energy-efficient solutions for autonomous navigation. As a random search strategy, the Lévy walk is optimal for diverse animals when foraging without external chemical cues. In this study, by combining these biological strategies for the first time, we propose a spiking neural network model for search and contour tracking of specific concentrations of environmental variables. Specifically, we first design a klinotaxis module using spiking neurons. This module works in conjunction with a klinokinesis module, allowing rapid searches for the concentration setpoint and subsequent contour tracking with small deviations. Second, we build a random exploration module. It generates a Lévy walk in the absence of concentration gradients, increasing the chance of encountering gradients. Third, considering local extrema traps, we develop a termination module combined with an escape module to initiate or terminate the escape in a timely manner. Experimental results demonstrate that the proposed model integrating these modules can switch strategies autonomously according to the information from a single sensor and control steering through output spikes, enabling the model worm to efficiently navigate across various scenarios.