Lei Ren, Lei Zhang^*

Energy Engineering, Vol.119, No.3, pp. 1179-1196, 2022, DOI:10.32604/ee.2022.018902

Abstract Due to the components at twice the fundamental frequency of output voltage in the instantaneous output power of a two-stage single-phase inverter (TSI), the second harmonic current (SHC) is generated in the front-end dc-dc converter (FDC). To reduce the SHC, optimizing the control strategy of the FDC is an effective and costless approach. From the view of visual impedance, this paper conducts an intensive study on the SHC reduction strategies. Origin of the SHC is illustrated first. Then, the equivalent circuit models of the FDC under different control strategies are proposed to analyse the SHC propagation characteristic. The derived model… More >

Indra Mamad Gandidi^1,2,*, Edy Suryadi³, Efri Mardawati³, Dwi Rustam Kendarto³, Nugroho Agung Pambudi^4,*

Energy Engineering, Vol.119, No.3, pp. 1169-1178, 2022, DOI:10.32604/ee.2022.018821

Abstract Pyrolysis is one of the thermal cracking methods to convert hydrocarbon to liquid fuel. The quantity and quality of the process are dependent on several condition including temperature, reaction time, catalyst, and the type of reactor. Meanwhile, a gasoline fraction was maximum product to be considered in the pyrolisis process. Therefore, this study aims to increase the gasoline fraction in liquid fuel using stepwise pyrolysis with a long bed catalytic reactor downstream (LBCR). The LBCR downstream was equipped with the top and bottom outlet and the fed source was mixed municipal solid waste (MMSW). The activated natural dolomite at 500°C… More >

Kehinde Adeyeye^1,*, Nelson Ijumba^1,2, Jonathan Colton^1,3

Energy Engineering, Vol.119, No.3, pp. 997-1015, 2022, DOI:10.32604/ee.2022.018677

Abstract This paper posits that a low-speed wind turbine design is suitable for harnessing wind energy in Africa. Conventional wind turbines consisting of propeller designs are commonly used across the world. A major hurdle to utilizing wind energy in Africa is that conventional commercial wind turbines are designed to operate at wind speeds greater than those prevalent in most of the continent, especially in sub-Sahara Africa (SSA). They are heavy and expensive to purchase, install, and maintain. As a result, only a few countries in Africa have been able to include wind energy in their energy mix. In this paper, the… More >

Bin Zhang, Boqiang Wei^*

Energy Engineering, Vol.119, No.3, pp. 1197-1218, 2022, DOI:10.32604/ee.2022.018411

Abstract The non-cascade permanent magnet synchronous motor control system has the advantages of simple structure and less adjustable parameters, but the non-cascade structure needs to solve the problem of over-current protection. In this paper, a current constrained control method is used to limit the starting current to a safe range. At the same time, to ensure the robustness and rapidity of the system, a super twist current constraint controller (CCSTA) is generated by combining super twist algorithm (STA) with current constraint control; Considering the diversity of internal and external disturbances, a functional disturbance observer (FDOB) is proposed to compensate the matched… More >

Tao Guo, Gang Tian, Zhimin Ao^*, Xi Fang, Lili Wei, Fei Li

Energy Engineering, Vol.119, No.3, pp. 985-996, 2022, DOI:10.32604/ee.2022.018185

Abstract Ground short circuit faults in current transmission lines are common in the power systems. In order to prevent the power system from aggravating the accident caused by short-circuit faults of transmission lines, a novel convolutional neural network (CNN) model is constructed to identify the short-circuit fault of the transmission line in the power system. The CNN model is mainly consisted of five convolutional layers, three max-pooling layers, one concatenate layer, one dropout layer, one fully connected layer, and a Softmax classifier. This method uses a fixed time window to intercept system short-circuit fault data, extracts the deep features of these… More >

Jiacheng Yang¹, Xiaohe Zhai¹, Zhongfu Tan^1,2,*, Zhenghao He¹

Energy Engineering, Vol.119, No.3, pp. 883-906, 2022, DOI:10.32604/ee.2022.018033

Abstract There is uncertainty in the electricity price of spot electricity market, which makes load aggregators undertake price risks for their agent users. In order to allow load aggregators to reduce the spot market price risk, scholars have proposed many solutions, such as improving the declaration decision-making model, signing power mutual insurance contracts, and adding energy storage and mobilizing demand-side resources to respond. In terms of demand side, calling flexible demand-side resources can be considered as a key solution. The user's power consumption rights (PCRs) are core contents of the demand-side resources. However, there have been few studies on the pricing… More >

Yanfei Chen¹, Jingjing He^2,*, Hao Chen^2,*, Xin Su², Bin Xie²

Energy Engineering, Vol.119, No.3, pp. 1239-1259, 2022, DOI:10.32604/ee.2022.017847

Abstract 20% n-butanol is blended in diesel by volume (noted as D80B20) and experiment has been carried out to study the effect on the combustion and emission characteristics based on a common rail diesel engine with exhaust gas recirculation (EGR) system. The results reveal that D80B20 has longer ignition delay, shorter combustion duration and higher maximum in-cylinder temperature than pure diesel (noted as D100). Further, the number concentration and volume concentration of ultrafine particles decrease significantly while NO_X emissions increase a little with the addition of n-butanol. When the exhaust gas is induced into cylinder, NO_X emissions significantly decrease and ultrafine… More >

Qiang Li^1,*, Lei Xue¹, Xia Lin²

Energy Engineering, Vol.119, No.3, pp. 1059-1074, 2022, DOI:10.32604/ee.2022.017687

Abstract For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet, it is very necessary to put forward the location method of distribution network equipment and capacity from the perspective of life cycle cost. Compared with the traditional energy network, the equipment capacity problem of energy interconnected distribution network which involves in electricity network, thermal energy network and natural gas network is comprehensively considered in this paper. On this basis, firstly, the operation architecture of energy interconnected distribution network is designed. Secondly, taking the grid connection location and configuration… More >

Lida Liao¹, Bo Xiao^1,2,*, Kan Huang^1,*, Bin Huang^1,3, Kang Zhang¹

Energy Engineering, Vol.119, No.3, pp. 1219-1238, 2022, DOI:10.32604/ee.2022.017471

Abstract With the increasingly stringent requirements for carbon emissions, countries have increased the scale of clean energy use in recent years. As an important new clean energy source, the ratio of wind power in energy utilization has been increasing. The horizontal axis wind turbine is the main form of wind power generation, which is subject to random wind loads during operation and is prone to various failures after a long period of operation, resulting in reduced power generation efficiency or even shutdown. In order to ensure stable external power transmission, it is necessary to perform fault diagnosis for wind turbines. However,… More >

Xin Zhang^*, Jinpeng Jiang, Haoran Zheng, Jihong Zhang

Energy Engineering, Vol.119, No.3, pp. 1117-1140, 2022, DOI:10.32604/ee.2022.017288

Abstract China consumes significant amount of natural gas in winter. The integrated community energy utilization system (ICEUS) cannot stabilize the output of electricity and heat if there is a shortage of natural gas. The operation cost of the system still needs improvement. An energy supply structure using garbage power as the core of ICEUS was established in the study. The optimal dispatching model of ICEUS was established using the regulating characteristic of the community load. The sine-cosine algorithm (SCA) based on nonlinear factors and segmented weight was presented to solve the optimal dispatching model of ICEUS. From the simulation results, compared… More >