• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.21-28
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• 2013

The paper proposes an optimal sizing method of a customer's battery energy storage system (BESS) which aims at managing the electricity demand of the customer to minimize electricity cost under the time of use(TOU) pricing. Peak load limit of the customer and charging and discharging schedules of the BESS are optimized on annual basis to minimize annual electricity cost, which consists of peak load related basic cost and actual usage cost. The optimal scheduling is used to assess the maximum cost savings for all sets of candidate capacities of BESS. An optimal size of BESS is determined from the cost saving curves via capacity of BESS. Case study uses real data from an apartment-type factory customer and shows how the proposed method can be employed to optimally design the size of BESS for customer demand management.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.27-34
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• 2014

The paper proposed a sizing method of an energy storage system(ESS) for peak shaving of high-speed railway substations based on load profile patterns of substations. A lithium based battery ESS was selected since it can produce high-power at high speed that peak shaving requires, and also takes up a relatively smaller space for installation. Adequate size of the ESS, minimum capacity which can technically meet a peak shaving target, was determined by collectively considering load patterns of a target substation, characteristics of the ESS to be installed, and optimal scheduling of the ESS. In case study, a local substation was considered to demonstrate the proposed sizing method. Also economic analysis with the determined size of ESS was performed to calculate electricity cost savings of the peak shaving ESS, and to offer pay-back period and return on investment.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.138-146
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• 2019

In this paper, we proposed a soft-switched synchronous buck converter, which can perform charging the battery. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss, resulting in small conduction loss, also. In this reason, the efficiency of the converter can be greatly improved even in high frequency. The size and weight of the converter can be reduced by high frequency operation of the converter. In this paper, we designed a battery charger with a switching frequency of 100 kHz. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery charger had soft switching characteristics. The simulation results for transient response to charge current for the designed converter show that the converter responds to charge current commands quickly within 0.05 ms.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2138-2145
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• 2017

A hybrid system combining renewable technologies with diesel generators is a promising solution for rural electrification. Myanmar has many renewable energy resources, and many regions that cannot be supplied with electricity from the main grid. Therefore, in this study, we select a village in Myanmar, which is located far away from the substation, and evaluate the economic feasibility of a hybrid system for the village considering the specific local conditions and resource availability. We consider a hybrid system composed of a photovoltaic source, diesel generator, battery energy storage system, and converter. The load profiles of the household data from the village, and the solar radiation profiles are determined. The advantages of the hybrid system, in terms of cost, reliability, and environmental effects are analyzed through simulations using commercial software. The simulation results show that, for the selected village in Myanmar, a hybrid system with battery energy storage can reduce the cost and greenhouse gas emissions while maintaining reliability. We also obtain an optimized design in terms of the component size for the selected hybrid system with battery energy storage.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1369-1375
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• 2017

This paper presents an optimal operation scheduling algorithm for a smart home with energy storage system, electric vehicle and distributed generation. The proposed algorithm provides the optimal charge and discharge schedule of the EV and the ESS. In minimizing the electricity costs of the smart home, it considers not only the cost of energy purchase from the grid but also the life cost of batteries. The life costs of batteries are calculated based on the relation between the depth of discharge and life time of battery. As the life time of battery depends on the charge and discharge pattern, optimal charge and discharge schedule should consider the life cost of batteries especially when there is more than one battery with different technical characteristics. The proposed algorithm can also be used for optimal selection of size and type of battery for a smart home.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.192-194
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• 2006

To elucidate possible challenges for outdoor practical use of dye-sensitized solar cells(DSC), compared with conventional Si solar cells. DSC modules still need the larger area than conventional Si solar modules to attain the same rated output because of lower photoelectron-chemical conversion efficiency. However, using batteries backup systems, the measured data shows that DSCs gathered over 12% more electricity than Si solar cells of the same rated output power in same outdoor condition. Moreover, battery charging time of DSC is about 1 hour faster than same rate of Si solar module. In this paper, 12 single DSC cells prepared for 4 serialized DSC cells was connected in 3 row parallel which have same output power rate of Si solar module. This DSC module was practiced generating characteristic experiment over outdoor daylight condition and applied with PV battery charger by using DC-DC converter. The main advantages of DSC module battery charger as compared with conventional Si solar module one are shorter charge time and lower cost.

• Journal of Auto-vehicle Safety Association
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• v.14 no.1
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• pp.55-61
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• 2022

Along with global environmental issues, the size of the electric vehicle market has recently skyrocketed. Various efforts have been made to extend mileage, one of the biggest problems of the electric vehicles, and development of batteries with high energy densities has led to exponential growth in mileage and performance. However, proper thermal management is essential because these high-performance batteries are affected by continuous heat generation and can cause fires due to thermal runaway phenomena. Therefore, thermal management of the battery is studied through the optimal design of the guide vanes, while utilizing the existing battery casing to ensure the safety of the electric vehicles. A battery from T-company, one of a manufacturer of the electric vehicles, was used for the research, and the commercial CFD software, ANSYS CFX V20.2, was used for analysis. The guide vanes were derived through optimal design based on a genetic algorithm with flow analysis. The optimized guide vanes show improved heat removal performance.

• ETRI Journal
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• v.45 no.4
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• pp.570-580
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• 2023

Sensor nodes are the most significant part of a wireless sensor network that offers a powerful combination of sensing, processing, and communication. One major challenge while designing a sensor node is power consumption, as sensor nodes are generally battery-operated. In this study, we proposed the design of a low-power, long range-based wireless sensor node with flexibility, a compact size, and energy efficiency. Furthermore, we improved power performance by adopting an efficient hardware design and proper component selection. The Nano Power Timer Integrated Circuit is used for power management, as it consumes nanoamps of current, resulting in improved battery life. The proposed design achieves an off-time current of 38.17309 nA, which is tiny compared with the design discussed in the existing literature. Battery life is estimated for spreading factors (SFs), ranging from SF7 to SF12. The achieved battery life is 2.54 years for SF12 and 3.94 years for SF7. We present the analysis of current consumption and battery life. Sensor data, received signal strength indicator, and signal-to-noise ratio are visualized using the ThingSpeak network.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.118-121
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• 1990

This paper describes development of an implantable power switching system for biotelemetry system. This system is designed and manufactured to achieve as small size and low power dissipation as possible, using pulse powered circult and CMOS technology. The function of the power switching system is to connect the implantable battery to implanted sensors and, electronics systems by receiving intermittent command signals from external circuits. The power dissipation of this system was about $15{\mu}W$ for a stand-by operation.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.197-198
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• 2018

This paper proposes a novel hybrid converter topology suitable for electric vehicle on-board battery chargers, which is a combination of the full-bridge (FB) and half-bridge (HB) LLC circuits. A full load controllability under wide output voltage range can be achieved with a small resonant inductance, which increases the efficiency and lowers the size and cost. Simulation results are shown to evaluate the dynamic performance of the proposed converter.