Open Access
ARTICLE
G. Indira Kishore1, M. Premkumar1,*, Ramesh Kumar Tripathi2, Chandra Sekhar Nalamati2
Energy Engineering, Vol.118, No.2, pp. 199-209, 2021, DOI:10.32604/EE.2021.014079
（This article belongs to this Special Issue: Advancements in Renewable Energy Systems with AI, Big Data, BlockChain, IoT, and Machine Learning Applications)
Abstract Renewable energy with sources such as photovoltaic (PV) or fuel cells
can be utilized for the generation of electrical power. But these sources generate
fewer voltage values and therefore require high gain converters to match with DC
bus voltage in microgrids. These high gain converters can be implemented with
switched capacitors to meet the required DC bus voltage. Switched capacitors
operate in a series and parallel combination during switching operation and produce high static gain, limits reverse voltage that appears across the components. A
novel converter is proposed that satisfies all the features such as high voltage gain,
only one… More >
Open Access
ARTICLE
Fenwicks Shombe Musonye1,*, Hiram Ndiritu2, Robert Kinyua3
Energy Engineering, Vol.118, No.2, pp. 211-224, 2021, DOI:10.32604/EE.2021.013890
Abstract Pinch Analysis is an attractive solution for reduction of thermal energy
costs in thermo-chemical industries. In this approach, maximum internally recoverable heat is determined and a heat exchange network is designed to meet
the recovery targets. The thermal performance of a heat exchanger over its lifetime is however a concern to industries. Thermal performance of a heat exchanger
is affected by many factors which include the physical properties of the shell and
tube materials, and the chemical properties of the heat transfer fluid. In this study,
thermal performance of shell and tube heat exchangers designed to meet heat
recovery targets… More >
Open Access
ARTICLE
Yanju Wei1,*, Shengcai Deng1, Jie Zhang1, Yajing Yang2, Hao Chen3
Energy Engineering, Vol.118, No.2, pp. 225-235, 2021, DOI:10.32604/EE.2021.012416
Abstract The aerodynamic breakup of the droplet has been intensely studied in this paper. We aim to establish a unified relationship between dimensionless kinematic parameters such as displacement, spreading diameter, Weber number, time, and so on. The breakup characteristics of the acoustic levitated ethanol droplet are experimentally investigated when exposed to an air jet flow. The breakup phenomenons were recorded with a high-speed camera. The breakup characteristics were analyzed, and the physical models of the moving and transforming behaviors were established to explain the breakup mechanisms. We found that the displacement of the windward side of the droplet follows free acceleration… More >
Open Access
ARTICLE
Shuowang Zhang1, Lingxiang Huang1,*, Dongran Song2,*, Ke Xu1, Xuebing Yang1, Xiaoping Song1
Energy Engineering, Vol.118, No.2, pp. 237-250, 2021, DOI:10.32604/EE.2021.014269
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract Yaw control system plays an important role in helping large-scale horizontal wind turbines capture the wind energy. To track the stochastic and fast-changing wind direction, the nacelle is rotated by the yaw control system. Therein, a difficulty consists in the variation speed of the wind direction much faster than the rotation speed of the nacelle. To deal with this difficulty, model predictive control has been recently proposed in the literature, in which the previewed wind direction is employed into the predictive model, and the estimated captured energy and yaw actuator usage are two contradictive objectives. Since the performance of the… More >
Open Access
ARTICLE
Jungang Wang1,*, Liqun Qian1, Shuairui Xu1, Ruina Mo2
Energy Engineering, Vol.118, No.2, pp. 251-264, 2021, DOI:10.32604/EE.2021.014143
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract Wind turbine is a key device to realize the utilization of wind energy, and it has been highly valued by all countries. But the mechanical gear transmission of the existing wind power device has the disadvantages of high vibration and noise, high failure rate, and short service time. Magnetic field modulation electromagnetic gear transmission is a new non-contact transmission method. However, the conventional modulation magnetic gear has low torque density and torque defects with large fluctuations. In order to overcome the gear transmission problems of the existing semi-direct drive wind power generation machinery and improve the electromagnetic performance of the… More >
Open Access
ARTICLE
Pulin Cao, Haoran Fan, Zilong Cai*
Energy Engineering, Vol.118, No.2, pp. 265-284, 2021, DOI:10.32604/EE.2021.014513
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract Since the voltage source converter based high voltage direct current (VSC-HVDC) systems owns the features of nonlinearity, strong coupling and multivariable, the classical proportional integral (PI) control is hard to obtain content control effect. Hence, a new perturbation observer based fractional-order PID (PoFoPID) control strategy is designed in this paper for (VSC-HVDC) systems with offshore wind integration, which can efficiently boost the robustness and control performance of entire system. Particularly, it employs a fractional-order PID (FoPID) framework for the sake of compensating the perturbation estimate, which dramatically boost the dynamical responds of the closed-loop system, and the cooperative beetle antennae… More >
Open Access
ARTICLE
Hongming Yang1,*, Qian Yu1, Xiao Huang1, Ben Niu2, Min Qi3
Energy Engineering, Vol.118, No.2, pp. 285-301, 2021, DOI:10.32604/EE.2021.013734
Abstract The two-way interaction between smart grid and customers will continuously play an important role in enhancing the overall efficiency of the green and low-carbon electric power industry and properly accommodating intermittent renewable energy resources. Thus far, the existing electricity pricing mechanisms hardly match the technical properties of smart grid; neither can they facilitate increasing end users participating in the electricity market. In this paper, several relevant models and novel methods are proposed for pricing scheme design as well as to achieve optimal decision-makings for market participants, in which the mechanisms behind are compatible with demand response operation of end users… More >
Open Access
ARTICLE
Quanjia Zuo1, Fanyi Meng1,*, Yang Bai2
Energy Engineering, Vol.118, No.2, pp. 303-322, 2021, DOI:10.32604/EE.2021.013239
Abstract As one of the most important commodity futures, the price forecasting of natural gas futures is of great significance for hedging and risk aversion. This paper mainly focuses on natural gas futures pricing which considers seasonality fluctuations. In order to study this issue, we propose a modified approach called six-factor model, in which the influence of seasonal fluctuations are eliminated in every random factor. Using Monte Carlo method, we first assess and comparative analyze the fitting ability of three-factor model and six-factor model for the out of sample data. It is found that six-factor model has better performance than three-factor… More >
Open Access
ARTICLE
Bilin Xu, Mei Han*
Energy Engineering, Vol.118, No.2, pp. 323-339, 2021, DOI:10.32604/EE.2021.013384
Abstract Based on the theory of ecological organization, this paper analyzes the
operation mechanism of chemical industry park (CIP) ecosystem by means of
dynamic simulation. The research shows that the CIP ecosystem is a complex ecological system whose operation mechanism includes two levels, namely individual enterprises and ecosystem. At the level of individual enterprise, there are
competition, symbiosis, invasion and other interactions between enterprises in
the CIP ecosystem. Through the pre-determined judgment of the competition
effect coefficient and the symbiosis effect coefficient, we calculate how the enterprises influence each other, and then generate their respective operation paths, and
finally realize the… More >
Open Access
ARTICLE
Chi Zhang, Yong Shi*, Xuwei Gui
Energy Engineering, Vol.118, No.2, pp. 341-361, 2021, DOI:10.32604/EE.2021.014229
Abstract To realize effective utilization of renewable energy sources, a novel
polymorphic topology with hybrid control strategy based LLC resonant converter
was analyzed and designed in this paper. By combining the merits of a full bridge
LLC resonant converter, three-level half bridge LLC resonant converter, and variable frequency control mode, the converter realizes an intelligent estimation of
input voltage by automatically changing its internal circuit topology. Under this
control strategy, different input voltages determine different operation modes.
This is achieved in full bridge LLC mode when the input voltage is low. If the
input voltage rises to a certain level, it… More >
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