Jingjing Tian¹, Shenglin Mo^1,*, Feng Zhao¹, Xiaoqiang Chen²

Energy Engineering, Vol.121, No.2, pp. 439-459, 2024, DOI:10.32604/ee.2023.029956

Abstract In this paper, an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid. The strategy includes primary and secondary control. Among them, the primary control suppresses the DC microgrid voltage fluctuation through the Ⅰ and Ⅱ section control, and the secondary control aims to correct the P-U curve of the energy storage system and the PV system, thus reducing the steady-state bus voltage excursion. The simulation results demonstrate that the… More >

Baogang Chen¹, Fenglin Miao^2,*, Jing Yang¹, Chen Qi², Wenyan Ji¹

Energy Engineering, Vol.121, No.2, pp. 541-555, 2024, DOI:10.32604/ee.2023.028327

Abstract Energy storage systems (ESS) and permanent magnet synchronous generators (PMSG) are speculated to be able to exhibit frequency regulation capabilities by adding differential and proportional control loops with different control objectives. The available PMSG kinetic energy and charging/discharging capacities of the ESS were restricted. To improve the inertia response and frequency control capability, we propose a short-term frequency support strategy for the ESS and PMSG. To this end, the weights were embedded in the control loops to adjust the participation of the differential and proportional controls based on the system frequency excursion. The effectiveness of the proposed control strategy was… More >

Jin Fan¹, Litao Niu², Cuiping Li³, Gang Zhang², He Li³, Yiming Wang³, Junhui Li^3,*, Qinglong Song³, Jiacheng Sun³, Jianglong Pan⁴, Fangfang Lai⁴

Energy Engineering, Vol.120, No.12, pp. 2857-2878, 2023, DOI:10.32604/ee.2023.029740

Abstract With the continuous development of new energy generation technology and the increasingly complex power grid environment, the traditional black start scheme cannot meet the requirements of today’s power grid in order to ensure the stable operation of the power system can be restored quickly in the face of large power outages, so a more complete black start scheme needs to be developed to cope with the new power system. With the development of energy storage technology, the limitations of the traditional black-start scheme can be solved by new energy farms with energy storage configuration. Therefore, this paper investigates the problems… More > Graphic Abstract

Louis F. Marie^*, Karina Sałek, Tadhg S. O’Donovan

Energy Engineering, Vol.120, No.10, pp. 2193-2209, 2023, DOI:10.32604/ee.2023.043075

Abstract Composite thermochemical energy storage (TCES) represents an exciting field of thermal energy storage which could address the issue of seasonal variance in renewable energy supply. However, there are open questions about their performance and the root cause of some observed phenomena. Some researchers have observed the breakdown of particles in their production phase, and in their use. This study seeks to investigate the underlying cause of this breakdown. SEM and EDX analysis have been conducted on MgCl₂ impregnated 13X zeolite composites of differing diameters, as well as LiX zeolite. This was done in order to study the level of impregnation… More > Graphic Abstract

Xianjing Zhong¹, Xianbo Sun^1,*, Yuhan Wu²

CMC-Computers, Materials & Continua, Vol.76, No.2, pp. 1599-1619, 2023, DOI:10.32604/cmc.2023.039912

Abstract To reduce the comprehensive costs of the construction and operation of microgrids and to minimize the power fluctuations caused by randomness and intermittency in distributed generation, a double-layer optimizing configuration method of hybrid energy storage microgrid based on improved grey wolf optimization (IGWO) is proposed. Firstly, building a microgrid system containing a wind-solar power station and electric-hydrogen coupling hybrid energy storage system. Secondly, the minimum comprehensive cost of the construction and operation of the microgrid is taken as the outer objective function, and the minimum peak-to-valley of the microgrid’s daily output is taken as the inner objective function. By iterating… More >

Mingming Shi^1,*, Jun Zhang², Xuefeng Ge¹, Juntao Fei¹, Jiajun Tan³

Energy Engineering, Vol.120, No.8, pp. 1885-1897, 2023, DOI:10.32604/ee.2023.025788

Abstract With the wide application of renewable energy power generation technology, the distribution network presents the characteristics of multi-source and complex structure. There are potential risks in the stability of power system, and the problem of power quality is becoming more and more serious. This paper studies and proposes a power optimization cooperative control strategy for flexible fast interconnection device with energy storage, which combines the flexible interconnection technology with the energy storage device. The primary technology is to regulate the active and reactive power of the converter. By comparing the actual power value of the converter with the reference value,… More >

Pengda Li, Chao Xu, Zhirong Liao^* , Xing Ju, Feng Ye

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-10, 2020, DOI:10.5098/hmt.15.10

Abstract This study numerically investigates the charging and discharging processes of a three-stages cascaded latent heat thermal energy storage unit using three molten salts as the phase change materials (PCMs). Each stage of the unit is a vertical shell-and-tube heat exchanger, whose shell side is filled with the PCM and air. The liquid fractions, temperatures, and accumulated thermal energy of the PCMs during the fully charging and discharging processes, as well as the effects of the HTF inlet temperature, are analyzed. The results show that lower melting temperature of the PCM causes faster charging rate and more released heat in the… More >

Enhui Sun^1,2, Jiahao Shi^1,2, Lei Zhang^1,2,*, Hongfu Ji^1,2, Qian Zhang^1,2, Yongyi Li^1,2

Energy Engineering, Vol.120, No.7, pp. 1583-1602, 2023, DOI:10.32604/ee.2023.027790

Abstract This paper studies the feasibility of a supply-side wind-coal integrated energy system. Based on grid-side data, the load regulation model of coal-fired power and the wind-coal integrated energy system model are established. According to the simulation results, the reasons why the wind-coal combined power supply is difficult to meet the grid-side demand are revealed through scenario analysis. Based on the wind-coal combined operation, a wind-coal-storage integrated energy system was proposed by adding lithium-iron phosphate battery energy storage system (LIPBESS) to adjust the load of the system. According to the four load adjustment scenarios of grid-side instructions of the wind-coal system,… More >

Zhenzhen Zhang^1,*, Qingquan Lv¹, Long Zhao¹, Qiang Zhou¹, Pengfei Gao¹, Yanqi Zhang¹, Yimin Li²

Energy Engineering, Vol.120, No.7, pp. 1637-1654, 2023, DOI:10.32604/ee.2023.026942

Abstract Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids. In this paper, an improved energy management strategy based on real-time electricity price combined with state of charge is proposed to optimize the economic operation of wind and solar microgrids, and the optimal allocation of energy storage capacity is carried out by using this strategy. Firstly, the structure and model of microgrid are analyzed, and the output model of wind power, photovoltaic and energy storage is established. Then, considering the interactive power cost between the microgrid and the main grid and… More >

Hasan S. Majdi^a,*, Azher M. Abed^b, Laith J. Habeeb^c

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.6

Abstract The present work presents and analyzes the results acquired from outdoor experimental measurements of a solar latent heat storage unit integrated with built-in thermal energy storage at the presence and absence of porous media. The tank consists of a porous media part, a packed of glass beds, and the fluid flowing through the void space surrounding the porous glass beds. The porous tanks were filled by 1.68 mm glass beds to form bed heights (h) of 10 and 20 cm. Results show that the maximum thermal storage of 110 min is achieved in hot flow rate qh=4 LPM, cold flow… More >