• 한국인터넷방송통신학회논문지
• /
• 제24권4호
• /
• pp.141-146
• /
• 2024

기존의 화석연료와 발전기를 통하여 에너지를 생산하고 즉시 소모하던 방식에서 에너지를 저장하고 효율적으로 생산하고 이용하기 위한 에너지저장장치(ESS, Energy Storage System)가 개발되었다[1]. 이러한 에너지저장장치에 현재까지 2차전지 리튬이온(Li-ion) 배터리를 가장 많이 사용하고 있다. 따라서 리튬이온 배터리의 성능, 수명, 안전성을 향상시키기 위하여 셀(Cell) 단위로 관리하는 BMS(Battery Management System)의 역할이 매우 중요하다[2]. 특히 BMS의 기능 중 셀 간의 불균형 전압을 균형적으로 맞추는 셀 밸런싱(Cell Balancing) 기법은 에너지저장장치에서 배터리의 최적화를 도모할 수 있다. 이러한 최적화를 통해 모든 셀이 동일한 전압과 용량을 유지하여 성능향상, 출력 안정성을 유지할 수 있다[3]. 따라서 본 논문에서는 셀 간의 불균형이 발생한 리튬이온 배터리를 충전할 때 BMS의 기능 중 하나인 셀 밸런싱 기법의 동작 특성에 대하여 살펴보고자 한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2018년도 추계학술대회
• /
• pp.131-132
• /
• 2018

The world market for BESS (Battery Energy Storage System) is growing rapidly, and battery technology is also developing. It is important to understand the battery characteristics and develop a control strategy to develop the optimal BMS (Battery Management System). In this paper, we compare and analyze the parameter characteristics of NCM LIB (Lithium Ion Battery) according to the temperature change.

• 신재생에너지
• /
• 제16권1호
• /
• pp.1-14
• /
• 2020

Liquid air energy storage (LAES) using gas liquefaction has attracted considerable attention because of its mature technology, high energy density, few geographical constraints, and long life span. On the other hand, LAES has not yet been commercialized and is being developed recently. Therefore, few studies have performed an economic analysis of LAES. In this study, the levelized cost of electricity was calculated and compared with that of other energy storage systems. As a result, the levelized cost of electricity of LAES was $371/MWh. This is approximately $292/MWh, $159/MWh, $118/MWh, and $3/MWh less than that of the LiCd battery, VRFB battery, Lead-acid battery, and NaS battery. In addition, the cost was approximately $62/MWh and $195/MWh more than that of Fe-Cr flow battery and PHS. Sensitivity analysis of the levelized cost of electricity according to the main economic factors was performed, and economic uncertainty analysis was performed through a Monte-Carlo simulation. The cumulative probability curve showed the levelized cost of electricity of LAES, reflecting price fluctuations in the air compressor cost, electricity cost, and standing reserve hourly fee.

• Journal of Power Electronics
• /
• 제13권4호
• /
• pp.516-527
• /
• 2013

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.

• Transactions on Electrical and Electronic Materials
• /
• 제17권6호
• /
• pp.311-316
• /
• 2016

Batteries are critical components of electric vehicles and energy storage systems. The connection of a battery to the power grid for charge and discharge greatly affects energy storage. Therefore, an accurate and easy-to-observe battery model should be established to achieve systematic design, simulation, and SOC (state of charge) estimations. In this review, several equivalent circuit models of representative significance are explained, and their respective advantages and disadvantages are compared to determine and outline their reasonable applications to Li-ion batteries. Numerous commonly used model parameter identification principles are summarized as well, and basic model verification methods are briefly introduced for the convenient use of such models.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 전력전자학술대회 논문집
• /
• pp.388-389
• /
• 2013

This paper presents the method for the fluctuation smoothing control by using relaxation time variable control of battery. When the output power of wind farm is changed suddenly, it is necessary to control the output power of wind farm. The smoothing relaxation time is changed within limits of battery output power. Using the hybrid energy storage system (HESS) combined with battery energy storage system and electric double layer capacitor, it is possible to control the output power of wind farm. The capacity of battery is determined by considering the case of the disconnecting wind farm from the grid. To verify the proposed method, simulations are carried out by using PSCAD/EMTDC with actual data of wind farm in the Jeju Island.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2016년도 추계학술대회 논문집
• /
• pp.15-16
• /
• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2010년도 추계학술대회
• /
• pp.224-225
• /
• 2010

This paper proposes a battery energy storage system using a photovoltaic generation system. The proposed system consists of a grid, battery and PV array. Considering a daily load profile, radiation and battery, operation modes are divided. An algorithm is presented based on modes. In the paper, operation modes and algorithms are verified through simulations.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제51권11호
• /
• pp.635-644
• /
• 2002

Many generating units can be in parallel connection to one battery and inverter. However, one of the biggest problems we encountered is that wind speed is fluctuated sharply in accordance with the unstable weather conditions. To solve this problem, we need energy storage equipment such as storage lead-acid battery. We design a system and analyze its modeling so that it supplies a stable power to the load through DC-AC inverter part. In this paper, we applied dual step-up/down buck-boost converter and dual high-frequency half-bridge converter to the proposed system. These converters are used to store energy in the battery regardless of the change of the wind speed. The operation process of two proposed types of converters for high-power battery charging is discussed along with simulation and experimental result. We design a charging circuit which is applicable in the actual wind power generation system for 30kw and confirm the circuit's validity.

• Journal of Power Electronics
• /
• 제15권4호
• /
• pp.1006-1017
• /
• 2015

This paper presents a finite control set model predictive control (FCS-MPC) strategy for the AC/DC matrix converter used in grid-connected battery energy storage system (BESS). First, to control the grid current properly, the DC current is also included in the cost function because of input and output direct coupling. The DC current reference is generated based on the dynamic relationship of the two currents, so the grid current gains improved transient state performance. Furthermore, the steady state error is reduced by adding a closed-loop. Second, a Luenberger observer is adopted to detect the AC input voltage instead of sensors, so the cost is reduced and the reliability can be enhanced. Third, a switching state pre-selection method that only needs to evaluate half of the active switching states is presented, with the advantages of shorter calculation time, no high dv/dt at the DC terminal, and less switching loss. The robustness under grid voltage distortion and parameter sensibility are discussed as well. Simulation and experimental results confirm the good performance of the proposed scheme for battery charging and discharging control.