This paper presents a simplified single-stage buck-boost rectifier as well as a proportional-integral (PI) and cascaded proportional-resonant (PR) control methods. The design of the proposed ...rectifier is based on a recently introduced buck-boost inverter with the elimination of low-frequency switches in the H-bridge. It is verified that the low-frequency switches are redundant, and the rectifier can operate when these switches are replaced with diodes. Elimination of four switches as well as their drivers not only simplifies the modulation scheme, but also reduces the overall cost of the proposed rectifier. Moreover, the proposed PI and cascaded PR control method ensures almost zero steady-state error in the dc-link voltage as well as in the grid current. The correct operation of proposed rectifier together with the proposed control method during buck and boost modes are confirmed with experimental results obtained from a 500W prototype. The steady-state and transient results are obtained to verify that the proposed rectifier has a wide ac grid voltage and dc-link voltage operation ranges.
In order to make the teleoperation system more practical, it is necessary to effectively control the tracking error convergence time of the teleoperation system. By combining the terminal sliding ...mode control method with the neural network adaptive control method, a bilateral continuous finite time adaptive terminal sliding mode control method is designed for the combined teleoperation system. The Lyapunov theory is used to analyze the stability of the closed-loop system, and the position tracking error is able to effectively converge in time. Finally, the effectiveness of the proposed control scheme is verified by MATLAB Simulink numerical simulation, and the numerical analysis of the results shows that the method has better system performance. Compared with the traditional two-sided control method (TPDC) of PD time-delay teleoperation system, the control method in this paper has good performance, improves stability, and makes steady-state errors smaller and better tracking.
Hydrogen energy storage systems (HydESS) and their integration with renewable energy sources into the grid have the greatest potential for energy production and storage while controlling grid demand ...to enhance energy sustainability. This paper presents a bibliometric analysis based on a comprehensive review of the highly cited articles on HydESS to provide a detailed insight into future directions and applications. The study was carried out by using the Scopus database search engine to look for filtered keywords in the HydESS and related research. It can be demonstrated that the HydESS literature expanded rapidly from 2016 to 2021 compared to 2011 to 2015. It is found that 89.17% of published articles explained control and test systems-based methods, whereas 10.83% of publications discuss review assessments. Our analysis of highly cited articles on HydESS highlights several aspects, such as methods and systems, issues, difficulties, and challenges to establishing current constraints and research gaps. This evaluation can enhance operational performance, environmental friendliness, energy savings, uninterrupted power supply service, cost benefits, on-site generation, and adaptability. It would be beneficial for technology development and the growth of the hydESS industry. This study may act as a guideline not only for academics in determining the line of research and generating additional discoveries, but also for the government in formulating financial strategies.
•Top-cited hydrogen energy storage system articles are reviewed under specific conditions.•Hydrogen storage integrated grids have the potential for energy sustainability.•A historical overview of hydrogen storage was analyzed using the Scopus database.•This survey has exhibited a developing hydrogen storage and renewable energy fields of research.•Bibliometric analysis was used to identify potential future research directions.
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Thin walled and high rib components (TWHRC) are widely used for rocket cabins, aircraft wings, panels and frames in aerospace equipment as critical load bearing structures. This paper ...is aimed to develop a novel multi-DOF envelope forming machine (MEFM) with parallel kinematic mechanism (PKM) to realize efficient manufacturing of TWHRC with high performance. Since the heavy load MEFM with PKM has many total differences with the light load PKM, such as dynamic error and precision control, this paper conducts research on dynamic error prediction modelling and precision control method for this novel heavy load MEFM.
Firstly, the configuration of MEFM is developed and the kinematic model of MEFM is established. Then, a RFC (rigid-flexible coupling) and RFE (rigid finite element) coupling dynamic model of MEFM is established considering time-variation of kinematic configuration caused by large deformation of all the kinematic elements. Based on the dynamic model, the dynamic deformation and error of MEFM are predicted and their generation mechanisms are revealed. It is found that the linear compression deformation of two-force links is the largest among all the kinematic elements, and it is the most sensitive to the heavy forming load and the most insensitive to the installation error of strain gauges, thus suiting for the feedback of large deformation of MEFM. Based on the above findings, a novel link strain feedback and dynamic error compensation control method is proposed. Finally, experiments under different control methods are conducted, showing that the motion precision of envelope tool and forming precision of formed components under the proposed control method are remarkably improved compared with that under the traditional control method (The geometric deviation of formed components under the proposed control method is remarkably reduced to −18 ∼ 32um from −64 ∼ 54um under the traditional control method). The experimental results verify that the proposed dynamic error prediction model and link strain feedback control method for heavy load MEFM are reasonable.
Renewable energy-based energy conversion technologies have become more relevant due to environmental considerations even though they are intermittent in nature. As a result, the concept of microgrid ...and microgrid control techniques have been evolved as major areas of power system research. Among different inverter control methods, the droop-based control method is more popular in microgrid systems due to its simplicity and non-requirement of expensive communication systems. The transient performance, power-sharing accuracy and decoupling between real and reactive power are improved by modifying the natural droop control method. In this study, the selected microgrid system consists of two inverters operating in parallel, two interconnecting lines and three loads. A state-space model of the microgrid is created based on the small-signal stability and the transient response is improved by introducing virtual impedance and dynamic droop gains. The different controller parameters are optimised using particle swarm optimisation ensuring stability. Eigenvalue analysis is done to analyse stability. The analysis of the response of the system for various disturbances validates the effectiveness of the proposed controller. The strategy developed ensures improved power-sharing capability with high values of natural droop gains without compromising stability by using optimised dynamic droop gains.
Wind and wave energy are the main forms of offshore energy. In this study, a new joint wind and wave energy (JWWE) power conversion system, which simultaneously features wind power generation and ...wave power generation, is investigated. In the JWWE power generation system, a dual-stator linear and rotary permanent magnet generator (DSLRPMG) is employed to directly convert the wind and wave energy. The topology and operating principles of the power generation system are analysed, and the rectifier topology with two three-phase bridge converter is introduced for the JWWE power generation system. On the basis of the vector control method, the mathematical model of the DSLRPMG is deduced. The virtual flux direct power control method without any AC voltage sensors is applied for the power generation system. A new decoupling control method including flux decoupling and power decoupling is proposed and analysed. Meanwhile, an experimental setup is constructed, and the experiments are done. Both the simulation and experimental results show the validity and correctness of the control strategy.
Building retrofitting towards nearly zero energy building (nZEB) with comfortable visual and thermal conditions, requires a comprehensive parametric analysis of building retrofit measures. This paper ...presented an optimization method to automate the procedure of finding the best combination of measures minimizing the building energy use and achieving the nZEB target while enhancing both thermal and visual comfort conditions. The study was performed by coupling of an Indoor climate and energy simulation software (IDA-ICE) and a generic optimization tool (GenOpt) through a Graphical Script interface and the optimization was applied to a typical office building located in Norway. The adopted method allowed the concurrent optimization of building envelope, building energy supply, fenestration, and shading device material, and control methods. Two constraint functions including visual and thermal comfort criteria were considered. Afterwards, PV panels were integrated with the building site for on-site production of electricity towards ZEB level. Findings demonstrated that the inclusive optimization approach could significantly decrease the building energy use, up to 77%, and improve both the thermal and visual comfort simultaneously. Furthermore, the best performance for the optimal solution was achieved when the shading device and window opening control methods functioned with solar radiation and indoor air temperature setpoints.
The carbon trading policy seeks to control carbon emissions by putting a price on carbon emissions and establishing a corresponding carbon market for trading. It is a significant move by China to ...address climate issues and achieve its Carbon Neutrality target. Therefore, assessing the policy effects of carbon trading is fundamental to its implementation nationwide. Based on the panel data of 30 provinces and cities in China from 2008 to 2018, this paper uses the Synthetic Control Method and Differences-in-Differences method to assess the effects of carbon trading policy on achieving Carbon Neutrality. By measuring the net carbon emissions, this research explores the level of Carbon Neutrality in each region. Based on the Five-sphere Integrated Plan (which covers the economy, politics, culture, social and ecological civilization), this research further verifies the impact paths of carbon trading policy on Carbon Neutrality. The results show that: First, carbon trading policy has a significant and sustainable effect on Carbon Neutrality. Second, from the perspective of the Five-sphere Integrated Plan, the carbon trading policy can help to reduce carbon sources and increase carbon sinks by adjusting the industrial structure, coordinating low-carbon policies, promoting cultural dissemination, increasing green space construction, and reducing energy intensity to achieve Carbon Neutrality. Third, cultural construction plays the most significant role in mediating carbon trading and Carbon Neutrality, followed by political construction.
•This paper examines the effectiveness of carbon trading policy for Carbon Neutrality.•We use the Synthetic Control Method and Difference-in-Differences method.•The impact paths of carbon trading policy are examined from the Five-sphere Integrated Plan perspective.•Carbon Neutrality should be incorporated into the Five-sphere Integrated Plan.•A cross-perspective study of the Five-sphere Integrated Plan, carbon trading with Chinese characteristics has been formed.
This study focuses on the synchronization control between the coupled neurons. The achievements of several synchronization control methods have been checked by evaluating the effects of the synaptic ...coupling weight alteration on the synchronization. Here, a neural ensemble has been constructed by utilizing the Hindmarsh Rose (HR) Neuron Model. The HR neurons have been linked to each other with the bidirectional coupling. The synchrony or the asynchrony states between these coupled neurons have been observed by using the standard deviation results. Here, firstly, the electrically and the chemically coupled HR neurons have been handled without using any control method, separately and the effects of the synaptic coupling weight alteration on the synchronic firing have been assessed by considering the features of the coupling types. Then, while the electrically coupled HR neurons are generally preferred in the available synchronization control studies; the Lyapunov, the back-stepping, and the feedback synchronization control methods have been adapted to both the electrically and the chemically coupled HR neurons. Thus, a remarkable contribution has been provided to the limited number of studies, which are about the synchronization control of the chemically coupled HR neurons. Also, the synchronization control between the electrically or the chemically coupled HR neurons has been provided by the back-stepping method for the first time. Finally, the differences between the membrane potentials of the coupled neurons have been calculated by utilizing an alternative error function. Since this function calculates the amplitude and the phase errors, separately; the effectiveness of these methods can be evaluated correctly in terms of the performing the minimum differences between the neural dynamics.
This paper studies the bipartite secure control design problem for nonlinear multi-agent systems (MASs) subject to denial-of-service (DoS) attacks over a signed digraph. By proposing an anti-attack ...control method, the nonlinear MASs can achieve the bipartite secure control goal in an insecure network and physical environment. In addition, to save communication resources, a novel distributed adaptive self-triggered control (ASTC) mechanism is proposed. Different from the traditional self-triggered control, the trigger interval can be dynamically adjusted according to the situation that the followers converge to the convex hull formed by the leaders, which makes the proposed control protocol based on ASTC able to balance the system performance and communication resources under DoS attacks through scheduling the inherent system resources. Furthermore, in order to overcome the problem of complexity explosion, a command filter is introduced into the design process to simplify the design process. The validity of our control scheme is demonstrated through a simulation example.
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