Shuqiao Dan^*

Energy Engineering, Vol.119, No.3, pp. 1047-1057, 2022, DOI:10.32604/ee.2022.015594 - 31 March 2022

Abstract There are several problems existing in the direct starting of asynchronous motor such as large starting current, reactive power absorption from network side and weak interference-resistance, etc. Aiming at this, a comprehensive energy-saving optimization model of asynchronous motor for voltage regulation based on static synchronous compensator (STATCOM) is put forward. By analyzing the working principle and operation performance of static synchronous compensator regulating voltage, a new energy-efficient optimization method for asynchronous motor is proposed based on the voltage regulator model to achieve soft start, continuous dynamic reactive power compensation and the terminal voltage stability control. More >

Guofeng Liu^*, Can Zhang, Zhengyi Zhu, Xuyan Wang

Energy Engineering, Vol.119, No.3, pp. 929-946, 2022, DOI:10.32604/ee.2022.014816 - 31 March 2022

Abstract Due to the increasing power consumption of whole society and widely using of new non-linear and asymmetric electrical equipment, power quality assessment problem in the new period has attracted more and more attention. The mathematical essence of comprehensive assessment of power quality is a multi-attribute optimal decision-making problem. In order to solve the key problem of determining the indicator weight in the process of power quality assessment, a rough analytic hierarchy process (AHP) is proposed to aggregate the judgment opinions of multiple experts and eliminate the subjective effects of single expert judgment. Based on the… More >

Xian Zhou¹, Fei Wang², Ziyu Wang³, Yunfeng Xu^1,*

Energy Engineering, Vol.119, No.2, pp. 653-664, 2022, DOI:10.32604/ee.2022.019072 - 24 January 2022

Abstract The reservoir is the networked rock skeleton of an oil and gas trap, as well as the generic term for the fluid contained within pore fractures and karst caves. Heterogeneity and a complex internal pore structure characterize the reservoir rock. By introducing the fractal permeability formula, this paper establishes a fractal mathematical model of oil-water two-phase flow in an oil reservoir with heterogeneity characteristics and numerically solves the mathematical model using the weighted least squares meshless method. Additionally, the method’s correctness is verified by comparison to the exact solution. The numerical results demonstrate that the… More >

Joselito Olalo^*

Energy Engineering, Vol.119, No.2, pp. 555-567, 2022, DOI:10.32604/EE.2022.018864 - 24 January 2022

Abstract Unlike plastic, biomass can also be converted and produce high quality of biofuel. Co-pyrolysis of coconut husk (CH) and laminated plastic packaging (LPP) were done in this study. Synergy between these two feedstock was calculated by using thermogravimetric (TGA) and derivative thermogravimetry (DTG) analysis. Different activation energies of the reactions in the co-pyrolysis of CH and LPP were evaluated using the Coats-Redfern method. Results showed an activation energy ranging from 8 to 37 kJ/mol in the different percentage composition of the co-pyrolysis. Also, thermal degradation happens in two-stages in the copyrolysis of CH and LPP, More >

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

Energy Engineering, Vol.119, No.2, pp. 767-780, 2022, DOI:10.32604/EE.2021.018617 - 24 January 2022

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 More >

Xiaolei Li^*

Energy Engineering, Vol.119, No.2, pp. 665-680, 2022, DOI:10.32604/ee.2022.019292 - 24 January 2022

Abstract Aiming at the difficulty of rolling bearing fault diagnosis of wind turbine under noise environment, a new bearing fault identification method based on the Improved Anti-noise Residual Shrinkage Network (IADRSN) is proposed. Firstly, the vibration signals of wind turbine rolling bearings were preprocessed to obtain data samples divided into training and test sets. Then, a bearing fault diagnosis model based on the improved anti-noise residual shrinkage network was established. To improve the ability of fault feature extraction of the model, the convolution layer in the deep residual shrinkage network was replaced with a Dense-Net layer. More >

Omar H. Abdalla^1,*, Gamal Abdel-Salam², Azza A. A. Mostafa³

Energy Engineering, Vol.119, No.2, pp. 569-589, 2022, DOI:10.32604/ee.2022.018693 - 24 January 2022

Abstract Battery Energy Storage System (BESS) is one of the potential solutions to increase energy system flexibility, as BESS is well suited to solve many challenges in transmission and distribution networks. Examples of distribution network’s challenges, which affect network performance, are: (i) Load disconnection or technical constraints violation, which may happen during reconfiguration after fault, (ii) Unpredictable power generation change due to Photovoltaic (PV) penetration, (iii) Undesirable PV reverse power, and (iv) Low Load Factor (LF) which may affect electricity price. In this paper, the BESS is used to support distribution networks in reconfiguration after a… More >

Xuehui Wang¹, Edward Wright¹, Zeyu Liu¹, Neng Gao^2,*, Ying Li³

Energy Engineering, Vol.119, No.2, pp. 801-814, 2022, DOI:10.32604/ee.2022.018241 - 24 January 2022

Abstract The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips, as it is characterised by excellent heat transfer ability and flexibility for miniaturisation. To boost the application of PHP, reliable heat transfer performance evaluation models are especially important. In this paper, a heat transfer correlation was firstly proposed for closed PHP with various working fluids (water, ethanol, methanol, R123, acetone) based on collected experimental data. Dimensional analysis was used to group the parameters. It was shown that the average absolute deviation (AAD) and correlation coefficient More >

Mohammad Zohurul Islam¹, Rabindra Nath Mondal², Suvash C. Saha^1,*

Energy Engineering, Vol.119, No.2, pp. 453-472, 2022, DOI:10.32604/ee.2022.018160 - 24 January 2022

Abstract

A depth understanding of fluid flow past a curved duct having rectangular cross-section with different aspect ratios (l) are essential for various engineering applications such as in chemical, mechanical, bio-mechanical and bio-medical engineering. So highly ambitious researchers have given significant attention to study new characteristics of fluid flow in a curved duct. The flow characterization in the rectangular duct has been studied over a wide range of numerical and selective experimental studies. However, proper knowledge with the effects of Coriolis force for different aspect ratios is important for better understanding of the transitional behaviour and

… More >

Min Deng¹, Quan Min¹, Ge Yang¹, Man Yu^2,3,*

Energy Engineering, Vol.119, No.2, pp. 739-754, 2022, DOI:10.32604/ee.2022.018025 - 24 January 2022

Abstract High-precision estimation of lithium battery SOC can effectively optimize vehicle energy management, improve lithium battery safety protection, extend lithium battery cycle life, and reduce new energy vehicle costs. Based on the forgetting factor recursive least square method (FFRLS), Thevenin equivalent circuit model and Singular Value Decomposition-Unscented Kalman Filter (SVD-UKF), the SVD-UKF combined lithium battery SOC estimation algorithm with model capacity update is proposed, aiming at further improving the SOC estimation accuracy of lithium battery. The parameter identification of Thevenin model is studied by using the forgetting factor recursive least square method. To overcoming the shortcomings… More >