Kaihui Zhao^1,2, Wenchang Liu¹, Tonghuan Yin³, Ruirui Zhou⁴, Wangke Dai¹ and Gang Huang^5,*

Energy Engineering, Vol., , pp. 1-14, DOI:10.32604/EE.2021.018617

Abstract This paper presents a novel model-free sliding mode control (MFSMC) method to improve the speed response of permanent magnet synchronous machine (PMSM) drive system. The ultra-local model (ULM) is first derived based on the input and the output of the PMSM. Then, the novel MFSMC method is presented, and the controller is designed based on ULM and MFSMC. A sliding mode observer (SMO) is constructed to estimate the unknown part of the ULM. The estimated unknown part is feedbacked to MFSMC controller to perform compensation for parameter perturbations and external disturbances. Compared with the sliding mode control (SMC) method, the… More >

Bo Zeng^*, Yixian Liu, Yangfan Luo

Energy Engineering, Vol., , DOI:10.32604/EE.2021.016678

Abstract In the future smart cities, parking lots (PLs) can accommodate hundreds of electric vehicles (EVs) at the same time. This trend creates an opportunity for PLs to serve as a potential flexibility resource, considering growing penetration of EVs and integration of distributed energy resources DER (such as photovoltaic and energy storages). Given this background, this paper proposes a comprehensive evaluation framework to investigate the potential role of DER-integrated PLs (DPL) with the capability of vehicle-to-grid (V2G) in improving the reliability of the distribution network. For this aim, first, an overview for the distribution system with DPLs is provided. Then, a… More >

Dan Wu¹, Yanbo Che¹, Wei Li^2,*, Wei He³, Dongyi Li⁴

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014818

Abstract With the significant progress of the “coal to electricity” project, the electric kiln equipment began to be connected to the distribution network on a large scale, which caused power quality problems such as low voltage, high harmonic distortion rate, and high reactive power loss. This paper proposes a two-stage power grid comprehensive resource optimization configuration model. A multi-objective optimization solution based on the joint simulation platform of Matlab and OpenDSS is developed. The solution aims to control harmonics and optimize reactive power. In the first stage, a multi-objective optimization model is established to minimize the active network loss, voltage deviation,… More >

Yinhe Bu¹, Xingping Zhang^1,2,3,*

Energy Engineering, Vol., , DOI:10.32604/EE.2021.015893

Abstract With the explosive growth of variable renewable energy, the balance between the supply and demand of the power grid is faced with new challenges. Based on the development experience from typical countries and the state quo in China, this paper further analyzes the system architecture and development trend of demand response under the background of Energy Internet. Five dimensions are considered: Energy Internet platform, demand response application scenarios, system architecture, information technology system construction, and demand response development trend. The results show that the application of the Energy Internet platform can effectively solve the problems of data acquisition and processing,… More >

Huiwen Xu^*, Zhen Wang

Energy Engineering, Vol., , DOI:10.32604/EE.2021.015028

Abstract In recent years, China has developed rapidly in terms of natural gas. Driven by regional economic integration, a regional natural gas market composed of neighboring provinces and cities has taken shape gradually, and it tends to grow toward the same direction in policy formulation, resource coordination, facility construction and market expansion. Based on the factors such as geographical location, economic conditions and natural gas consumption, this thesis tends to conduct a horizontal comparative analysis on the economic development conditions, natural gas consumption characteristics and natural gas pipeline network density of the three regions with obvious regional integration feature in China.… More >

Nan Li¹, Ruiyang Xu¹, Caihong Zhang^1,*, Guoping Wu²

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014741

Abstract An improved radiation transmission and thermal efficiency model for solar ponds has been proposed based on both the Hull Model and Wang/Seyed-Yagoobi Model in this paper. The new model is more accurate to actual measured conditions because multiple reflections and turbidity effects are included. Absorption penetration, thermal conductivity loss and thermal efficiency under different Non-Convective Zone thicknesses are numerically analyzed and thoroughly discussed. The results show that ΔT/I0 plays a critical role for the thermal efficiency of solar pond. Furthermore, it is found through calculation that there is an optimum thickness of the Non-Convective Zone. When the Non-Convective Zone thickness… More >

Anfeng Zhu, Zhao Xiao, Qiancheng Zhao^*

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014177

Abstract Due to the frequent changes of wind speed and wind direction, the accuracy of wind turbine (WT) power prediction using traditional data preprocessing method is low. This paper proposes a data preprocessing method which combines POT with DBSCAN (POT-DBSCAN) to improve the prediction efficiency of wind power prediction model. Firstly, according to the data of WT in the normal operation condition, the power prediction model of WT is established based on the Particle Swarm Optimization (PSO) Arithmetic which is combined with the BP Neural Network (PSO-BP). Secondly, the wind-power data obtained from the supervisory control and data acquisition (SCADA) system… More >

Chunxue Gao^1,*, Yu Hao¹, Qiuxin Liu^1,2

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014703

Abstract Based on the characteristics of sewage from beauty salons, a simulation model of a small sewage source heat pump triple supply system that can be applied to such places is established to optimize the operating conditions of the system. The results show that with the increase of sewage temperature and flow, the performance of the system also increases. In summer conditions, the system provides cooling, recovers waste heat and condensed heat from sewage, with a COP value of 8.97; in winter conditions, the system heats and produces hot water, with a COP value of 2.44; in transitional seasons, only hot… More >

Mamdouh El Haj Assad^1,*, Ali Khosravi², Mohammad AlShabi³, Bassam Khuwaileh³, Abdul-Kadir Hamid⁴

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014590

Abstract In this work, a life cycle analysis is accomplished for flat plate solar collectors. The purpose of this investigation is to predict the energy consumption during the manufacturing processes that results in carbon dioxide emissions. Energy consumption and system efficiency enhancement will be studied and predicted. CES EduPack software is used to perform the analysis of the currently commercial system, and the suggested changes are implemented to increase the efficiency and make the comparison. Even though cost analysis is done, the priority of selection is given to the most energy conserving and environmentally friendly alternative. However, if the compared alternatives… More >

Peng Qi^1,*, Yu Shang^2,*

Energy Engineering, Vol., , DOI:10.32604/EE.2021.014203

Abstract With the increasingly prominent environmental problems of abandoned coal mines, this paper discussed the significance of environmental vulnerability assessment of abandoned coal mines. Environmental vulnerability assessment is essentially an assessment of environmental quality. At present, the research object of environmental impact assessment method and program of mine is mostly single factor. However, the impact of abandoned coal mine on the environment is multifaceted, which was summarized into nine prominent common problems. Based on these nine factors, the environmental vulnerability assessment model of abandoned coal mine based on multifactor evaluation was established by using the analytic hierarchy process (AHP) method, the… More >