Relevant bibliographies by topics / Hybrid computers Transients / Journal articles
To see the other types of publications on this topic, follow the link: Hybrid computers Transients.

Journal articles on the topic 'Hybrid computers Transients'

Author: Grafiati
Published: 4 June 2021
Last updated: 12 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Hybrid computers Transients.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Go, Seok-Il, and Joon-Ho Choi. "Design and Dynamic Modelling of PV-Battery Hybrid Systems for Custom Electromagnetic Transient Simulation." Electronics 9, no. 10 (October 11, 2020): 1651. http://dx.doi.org/10.3390/electronics9101651.

Full text
Abstract:
Battery energy storage systems (BESS) can alleviate the unstable effects of intermittent renewable energy systems, such as solar and wind power systems. In addition, a BESS can level the load of the existing utility grid. The penetration rate of this type of system is expected to increase in the future power grid, i.e., the microgrid. In this paper, a modeling technique is proposed that allows users to customize the photovoltaic (PV) battery hybrid systems. A dynamic power system computer-aided design/electromagnetic transients including DC system (PSCAD/EMTDC) model of a PV battery hybrid system is presented in this paper. Dynamic modeling of PV arrays, BESS, maximum power point tracking (MPPT) algorithms, and bidirectional converters are provided as well. The PV model, battery model, and MPPT control model are designed using a user-defined model (UDM) for custom electromagnetic transient simulation. A control method for stabilizing the output of the PV battery hybrid system is proposed. Finally, a PSCAD/EMTDC simulation is conducted to verify the effectiveness of the operating algorithm.
APA, Harvard, Vancouver, ISO, and other styles
2

NA, LIU. "MATHEMATICAL MODELING OF HYBRID VEHICLE’S RECUPERATION BRAKING MODE. SIMULATION OF THE HYBRID VEHICLE’S RECUPERATION BRAKING MODE." Science Journal Innovation Technologies Transfer, no. 2020-4 (September 28, 2020): 70–81. http://dx.doi.org/10.36381/iamsti.4.2020.70-81.

Full text
Abstract:
The paper considers the synthesis of mathematical model of recuperation braking mode for hybrid vehicle as a complex control object. The results of computer simulation as diagrams of transients of different operating parameters of hybrid vehicle power system are obtained on the basis of developed model. The analysis of simulation results confirms the adequacy of the mathematic model of the recuperation braking mode of hybrid vehicle to real processes. The developed model can be used for synthesis of automatic control systems of the electric motors, power converters, power supplies and chargers for hybrid vehicles.
APA, Harvard, Vancouver, ISO, and other styles
3

Wang, Guoteng, Huangqing Xiao, Liang Xiao, Zheren Zhang, and Zheng Xu. "Electromechanical Transient Modeling and Control Strategy of Decentralized Hybrid HVDC Systems." Energies 12, no. 15 (July 24, 2019): 2856. http://dx.doi.org/10.3390/en12152856.

Full text
Abstract:
This paper studies the electromechanical transient model and the control strategy of line commutated converter (LCC) and modular multilevel converter (MMC) based decentralized hybrid High Voltage Direct Current (HVDC) Transmission systems. The decentralized hybrid HVDC system is a new type of topology, and the related electromechanical transient model and control strategy have not been studied well. In this paper, the electromechanical transient model of a decentralized hybrid HVDC system is devloped through mathematical deduction. This model can be easily implemented in electromechanical transient simulation software and meet the time domain simulation requirements of large-scale systems. Then, in order to ensure the safe absorption of the DC power under various conditions, an optimal power flow model considering the decentralized hybrid HVDC system is proposed. Finally, the electromechanical transient model proposed in this paper is verified by the electromagnetic transient model, and the control strategy is validated in a modified New England 39-bus system.
APA, Harvard, Vancouver, ISO, and other styles
4

Vidal-Albalate, Ricardo, and Jaume Forner. "Modeling and Enhanced Control of Hybrid Full Bridge–Half Bridge MMCs for HVDC Grid Studies." Energies 13, no. 1 (January 1, 2020): 180. http://dx.doi.org/10.3390/en13010180.

Full text
Abstract:
Modular multilevel converters (MMCs) are expected to play an important role in future high voltage direct current (HVDC) grids. Moreover, advanced MMC topologies may include various submodule (SM) types. In this sense, the modeling of MMCs is paramount for HVDC grid studies. Detailed models of MMCs are cumbersome for electromagnetic transient (EMT) programs due to the high number of components and large simulation times. For this reason, simplified models that reduce the computation times while reproducing the dynamics of the MMCs are needed. However, up to now, the models already developed do not consider hybrid MMCs, which consist of different types of SMs. In this paper, a procedure to simulate MMCs having different SM topologies is proposed. First, the structure of hybrid MMCs and the modeling method is presented. Next, an enhanced procedure to compute the number of SMs to be inserted that takes into account the different behavior of full-bridge SMs (FB-SMs) and half-bridge submodules (HB-SMs) is proposed in order to improve the steady-state and dynamic response of hybrid MMCs. Finally, the MMC model and its control are validated by means of detailed PSCAD simulations for both steady-state and transients conditions (AC and DC faults).
APA, Harvard, Vancouver, ISO, and other styles
5

Na, Liu. "MATHEMATICAL MODELING OF HYBRID VEHICLE’S RECUPERATION BRAKING MODE." Management of Development of Complex Systems, no. 44 (November 30, 2020): 182–87. http://dx.doi.org/10.32347/2412-9933.2020.44.182-187.

Full text
Abstract:
The paper considers the synthesis of mathematical model of recuperation braking mode for hybrid vehicle as a complex control object. The results of computer simulation as diagrams of transients of different operating parameters of hybrid vehicle power system are obtained on the basis of developed model. The analysis of simulation results confirms the adequacy of the mathematic model of the recuperation braking mode of hybrid vehicle to real processes. The developed model can be used for synthesis of automatic control systems of the electric motors, power converters, power supplies and chargers for hybrid vehicles. Hematical and simulation models of the hybrid vehicle’s recuperation braking mode is carried out. The presented models are based on equations of physics of processes and allow to study the recuperation braking mode of the different types hybrid vehicles under various conditions and parameters values (initial linear vehicle’s speed, electrical power of generator, inclination angle and the quality of the road surface, etc.). The designed mathematical model has a rather high adequacy to the real processes, which take place in the hybrid vehicles in the recuperation braking mode, that is confirmed by the obtained simulation results in the form of graphs of transients of the main variables changes. Further research should be conducted towards the development of the functional structures, control devices as well as software and hardware for automatic control systems of the different types hybrid vehicles on the basis of the obtained mathematical and simulation models.
APA, Harvard, Vancouver, ISO, and other styles
6

Veerashekar, Kishan, Halil Askan, and Matthias Luther. "Qualitative and Quantitative Transient Stability Assessment of Stand-Alone Hybrid Microgrids in a Cluster Environment." Energies 13, no. 5 (March 10, 2020): 1286. http://dx.doi.org/10.3390/en13051286.

Full text
Abstract:
Neighboring stand-alone hybrid microgrids with diesel generators (DGs) as well as grid-feeding photovoltaics (PV) and grid-forming battery storage systems (BSS) can be coupled to reduce fuel costs and emissions as well as to enhance the security of supply. In contrast to the research in control and small-signal rotor angle stability of microgrids, there is a significant lack of knowledge regarding the transient stability of off-grid hybrid microgrids in a cluster environment. Therefore, the large-signal rotor angle stability of pooled microgrids was assessed qualitatively and also quantitatively in this research work. Quantitative transient stability assessment (TSA) was carried out with the help of the—recently developed and validated—micro-hybrid method by combining time-domain simulations and transient energy function analyses. For this purpose, three realistic dynamic microgrids were modelled regarding three operating modes (island, interconnection, and cluster) as well as the conventional scenario “classical” and four hybrid scenarios (“storage”, “sun”, “sun & storage”, and “night”) regarding different instants of time on a tropical partly sunny day. It can be inferred that, coupling hybrid microgrids is feasible from the voltage, frequency, and also transient stability point of view. However, the risk of large-signal rotor angle instability in pooled microgrids is relatively higher than in islanded microgrids. Along with critical clearing times, new stability-related indicators such as system stability degree and corrected critical clearing times should be taken into account in the planning phase and in the operation of microgrids. In principle, a general conclusion concerning the best operating mode and scenario of the investigated microgrids cannot be drawn. TSA of pooled hybrid microgrids should be performed—on a regular basis especially in the grid operation—for different loading conditions, tie-line power flows, topologies, operating modes, and scenarios.
APA, Harvard, Vancouver, ISO, and other styles
7

Traverso, Alberto, Aristide Massardo, Rory A. Roberts, Jack Brouwer, and Scott Samuelsen. "Gas Turbine Assessment for Air Management of Pressurized SOFC/GT Hybrid Systems." Journal of Fuel Cell Science and Technology 4, no. 4 (June 9, 2006): 373–83. http://dx.doi.org/10.1115/1.2714567.

Full text
Abstract:
This paper analyzes and compares transient and steady-state performance characteristics of different types of single-shaft turbo-machinery for controlling the air through a pressurized solid oxide fuel cell (SOFC) stack that is integrated into a SOFC/GT pressurized hybrid system. Analyses are focused on the bottoming part of the cycle, where the gas turbine (GT) has the role of properly managing airflow to the SOFC stack for various loads and at different ambient conditions. Analyses were accomplished using two disparate computer programs, which each modeled a similar SOFC/GT cycle using identical generic gas turbine performance maps. The models are shown to provide consistent results, and they are used to assess: (1) the influence of SOFC exhaust composition on expander behavior for on-design conditions, (2) the off-design performance of the bypass, bleed, and variable speed controls for various part-load conditions and for different ambient conditions; (3) the features of such controls during abrupt transients such as load trip and bypass/bleed valve failure. The results show that a variable speed microturbine is the best option for off-design operation of a SOFC/GT hybrid system. For safety measures a bleed valve provides adequate control of the system during load trip. General specifications for a radial GT engine for integration with a 550kW pressurized SOFC stack are identified, which allow operation under a wide range of ambient conditions as well as several different cycle configurations.
APA, Harvard, Vancouver, ISO, and other styles
8

D’Ovidio, Gino, Antonio Ometto, and Carlo Villante. "A Novel Optimal Power Control for a City Transit Hybrid Bus Equipped with a Partitioned Hydrogen Fuel Cell Stack." Energies 13, no. 11 (May 26, 2020): 2682. http://dx.doi.org/10.3390/en13112682.

Full text
Abstract:
The development of more sustainable and zero-emissions collective transport solutions could play a very important measure in the near future within smart city policies. This paper tries to give a contribution to this aim, proposing a novel approach to fuel cell vehicle design and operation. Traditional difficulties experienced in fuel cell transient operation are, in fact, normally solved in conventional vehicle prototypes, through the hybridization of the propulsion system and with the complete fulfillment of transients in road energy demand through a high-capacity onboard energy storage device. This makes it normally necessary to use Li-ion battery solutions, accepting their restrictions in terms of weight, costs, energy losses, limited lifetime, and environmental constraints. The proposed solution, instead, introduces a partitioning of the hydrogen fuel cell (FC) and novel optimal power control strategy, with the aim of limiting the capacity of the energy storage, still avoiding FC transient operation. The limited capacity of the resulting energy storage systems which, instead, has to answer higher power requests, makes it possible to consider the utilization of a high-speed flywheel energy storage system (FESS) in place of high energy density Li-ion batteries. The proposed control strategy was validated by vehicle simulations based on a modular and parametric model; input data were acquired experimentally on an operating electric bus in real traffic conditions over an urban bus line. Simulation results highlight that the proposed control strategy makes it possible to obtain an overall power output for the FC stacks which better follows road power demands, and a relevant downsizing of the FESS device.
APA, Harvard, Vancouver, ISO, and other styles
9

Breitwieser, Christian, Christoph Pokorny, and Gernot R. Müller-Putz. "A hybrid three-class brain–computer interface system utilizing SSSEPs and transient ERPs." Journal of Neural Engineering 13, no. 6 (October 27, 2016): 066015. http://dx.doi.org/10.1088/1741-2560/13/6/066015.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Zhang, Bingda, Shipei Nie, and Zhao Jin. "Electromagnetic Transient-Transient Stability Analysis Hybrid Real-Time Simulation Method of Variable Area of Interest." Energies 11, no. 10 (October 1, 2018): 2620. http://dx.doi.org/10.3390/en11102620.

Full text
Abstract:
To make the object of electromagnetic transient (EMT) simulation flexible to change, the authors propose using the method of electromagnetic transient-transient stability analysis (TSA) hybrid real-time simulation of the variable area of interest. The area where the fault is to be set, or where the operation takes place, is defined as the area of interest. The simulation object is divided into multiple sub-networks. The EMT simulation range is determined according to the voltage drop depth at the boundary of the adjacent sub-network caused by the three-phase short-circuit fault at the boundary of an area of interest. The Norton equivalent is obtained by using the sub-network as a basic unit. The electromagnetic sub-network forms its own Norton equivalent on the TSA side by means of the Norton equivalent admittance of its TSA model. Based on this, the overall framework of hybrid real-time simulation of the variable area of interest is constructed. The fundamental phasor prediction and Norton equivalent current source prediction are adopted to reduce the interface error. The performance of the proposed method in terms of feasibility, flexibility, and effectiveness have been verified by the simulation studies on the IEEE 118-bus system.
APA, Harvard, Vancouver, ISO, and other styles
11

Floquet, A., and M. C. Dubourg. "Nonaxisymmetric Effects for Three-Dimensional Analysis of a Brake." Journal of Tribology 116, no. 3 (July 1, 1994): 401–7. http://dx.doi.org/10.1115/1.2928852.

Full text
Abstract:
A three-dimensional model of axisymmetric moving solids submitted to nonaxisymmetric transient heat flux conditions is presented in this paper. Temperature fields are obtained using a new hybrid FFT-FEM method that combines Fourier transform techniques and finite element method. A fast Fourier form algorithm is used which leads to inexpensive computer time. Validation tests are presented. Efficiency of the method is demonstrated.
APA, Harvard, Vancouver, ISO, and other styles
12

Yao, Tianliang, Zhiwei Li, Jiping Qu, Zhaoxiong Li, Qi Zhao, and Guopeng Zhao. "Research on Simplified Model of AC/DC Hybrid Microgrid for Fault Analysis." Electronics 9, no. 2 (February 20, 2020): 358. http://dx.doi.org/10.3390/electronics9020358.

Full text
Abstract:
The AC/DC hybrid microgrid, which takes into account the access requirements of AC and DC sources and loads, optimizes the structure of traditional distribution networks. The application of power electronic transformers as the core of its energy management, with electrical isolation and accurate control of the voltage, current and power flow by the control system, enables the microgrid to achieve a more flexible and stable transmission mode. Because the power electronic transformer combines the power electronic device and the high-frequency transformer, its frequent switching causes the electromagnetic transient simulation to take too long. Therefore, by simplifying control loops and converters, this paper proposes a simplified model for the microgrid system power flow and the dynamic response under exposure to a fault. The mathematical model equivalent simplification method is used in this paper. This method is concise and efficient and does not rely on the performance of a computer or change the program algorithm of the software. The simplified model was built based on PSCAD (Power System Computer Aided Design) simulation software and was carried out under short circuit fault conditions to verify its validity. The comparison of the simulation’s time consumption and accuracy shows that model simplification can significantly improve the simulation speed, with an acceptable error rate, and its dynamic response maintains good consistency with that of the detailed electromagnetic transient model. Therefore, it can be applied to the transient electromagnetic simulation fault analysis of the AC/DC hybrid microgrid.
APA, Harvard, Vancouver, ISO, and other styles
13

Xiao, Liang, Yan Li, Huangqing Xiao, Zheren Zhang, and Zheng Xu. "Electromechanical Transient Modeling of Line Commutated Converter-Modular Multilevel Converter-Based Hybrid Multi-Terminal High Voltage Direct Current Transmission Systems." Energies 11, no. 8 (August 13, 2018): 2102. http://dx.doi.org/10.3390/en11082102.

Full text
Abstract:
A method for electromechanical modeling of line commutated converter (LCC)-modular multilevel converter (MMC)-based hybrid multi-terminal High Voltage Direct Current Transmission (HVDC) systems for large-scale power system transient stability study is proposed. Firstly, the general idea of modeling the LCC-MMC hybrid multi-terminal HVDC system is presented, then the AC-side and DC-side models of the LCC/MMC are established. Different from the conventional first-order DC-side model of the MMC, an improved second-order DC-side model of the MMC is established. Besides considering the firing angle limit of the LCC, a sequential power flow algorithm is proposed for the initialization of LCC-MMC hybrid multi-terminal HVDC system. Lastly, simulations of small scale and large scale power systems embedded with a three-terminal LCC-MMC hybrid HVDC system are performed on the electromechanical simulation platform PSS/E. It is demonstrated that if the firing angle limit is not considered, the accuracy of the power flow solutions will be greatly affected. Steady state calculation and dynamic simulation show that the developed LCC-MMC hybrid MTDC model is accurate enough for electromechanical transient stability studies of large-scale AC/DC system.
APA, Harvard, Vancouver, ISO, and other styles
14

Лаженко, А. С., and Т. Я. Біла. "ОЦІНКА ЕНЕРГОЕФЕКТИВНОСТІ ВИКОРИСТАННЯ СИСТЕМ КЕРУВАННЯ МОТОР-КОМПРЕСОРОМ ПОБУТОВОГО ХОЛОДИЛЬНИКА." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 146, no. 3 (January 11, 2021): 58–68. http://dx.doi.org/10.30857/1813-6796.2020.3.5.

Full text
Abstract:
Determining the rational structure of the automatic control system of the motor-compressor, which provides minimal energy losses when switching on and going to a steady state mode of operation of a household refrigerator. The methods of simulation modeling, comparative analysis, research of control systems and the main provisions of technical thermodynamics and the theory of automatic control are used in the work. The paper considers the principle of operation of the refrigeration unit of a household refrigerator, schematically shows its main elements and the relationship with the steam compression cycle. Simulation models of automatic control systems based on proportional-integral-differential controller, fuzzy and hybrid controllers have been developed. The proposed models allow to evaluate the quality of temperature control in the refrigeration compartment and to determine energy losses during transients. The results of computer simulation of transients in temperature control systems due to changes in the performance of the motor-compressor and the obtained values of power losses are presented. It is established that the smallest losses of the electric power at instant increase of heat inflows in refrigerating department occur at application of a fuzzy regulator. It is determined that the use of fuzzy controllers in automatic control systems reduces the duration of transients, the time of the first negotiation, the number of oscillations, but leads to static error and increases the maximum deviation from the set temperature in the refrigerator compartment. Simulation models of control systems of the motor-compressor of a household refrigerator for assessment of quality of regulation and definition of losses of the electric power during transient processes are developed. The ways to increase the energy efficiency of household refrigerators through the introduction of control systems with fuzzy regulators are proposed.
APA, Harvard, Vancouver, ISO, and other styles
15

Лаженко, А. С., and Т. Я. Біла. "ОЦІНКА ЕНЕРГОЕФЕКТИВНОСТІ ВИКОРИСТАННЯ СИСТЕМ КЕРУВАННЯ МОТОР-КОМПРЕСОРОМ ПОБУТОВОГО ХОЛОДИЛЬНИКА." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 146, no. 3 (January 11, 2021): 58–68. http://dx.doi.org/10.30857/1813-6796.2020.3.5.

Full text
Abstract:
Determining the rational structure of the automatic control system of the motor-compressor, which provides minimal energy losses when switching on and going to a steady state mode of operation of a household refrigerator. The methods of simulation modeling, comparative analysis, research of control systems and the main provisions of technical thermodynamics and the theory of automatic control are used in the work. The paper considers the principle of operation of the refrigeration unit of a household refrigerator, schematically shows its main elements and the relationship with the steam compression cycle. Simulation models of automatic control systems based on proportional-integral-differential controller, fuzzy and hybrid controllers have been developed. The proposed models allow to evaluate the quality of temperature control in the refrigeration compartment and to determine energy losses during transients. The results of computer simulation of transients in temperature control systems due to changes in the performance of the motor-compressor and the obtained values of power losses are presented. It is established that the smallest losses of the electric power at instant increase of heat inflows in refrigerating department occur at application of a fuzzy regulator. It is determined that the use of fuzzy controllers in automatic control systems reduces the duration of transients, the time of the first negotiation, the number of oscillations, but leads to static error and increases the maximum deviation from the set temperature in the refrigerator compartment. Simulation models of control systems of the motor-compressor of a household refrigerator for assessment of quality of regulation and definition of losses of the electric power during transient processes are developed. The ways to increase the energy efficiency of household refrigerators through the introduction of control systems with fuzzy regulators are proposed.
APA, Harvard, Vancouver, ISO, and other styles
16

Neumann, Philipp. "On transient hybrid Lattice Boltzmann–Navier-Stokes flow simulations." Journal of Computational Science 17 (November 2016): 482–90. http://dx.doi.org/10.1016/j.jocs.2016.02.003.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Xu, Lin, Yong-Hong Tang, Wei Pu, and Yang Han. "Hybrid electromechanical-electromagnetic simulation to SVC controller based on ADPSS platform." Journal of Energy in Southern Africa 25, no. 4 (December 19, 2014): 112–22. http://dx.doi.org/10.17159/2413-3051/2014/v25i4a2244.

Full text
Abstract:
To test the dynamic performance and damping features of a static var compensator (SVC) controller accurately in large-scale interconnected AC/DC hybrid power systems, it is of vital significance to build the detailed electromagnetic transient model. However, it is unrealistic and time-consuming to build the detailed models of all the devices in the actual large-scale power grid. Utilizing the hybrid simulation function in the advanced digital power system simulator (ADPSS) and by dividing the large-scale power grid into the electromagnetic transient sub-grids and electromechanical sub-grids, the computation speed of real-time simulation is remarkably enhanced by the parallel computational capabilities of digital simulator. The SVC controller and the nearby substation are modelled in the electromagnetic transient sub-grid, and the residue sub-networks are modelled in the electromechanical sub-grid. This paper focuses on the mechanism of the hybrid electromechanical and electromagnetic simulation, the detailed modelling and the ADPSS-based digital closed-loop test methodologies of the SVC controller. Eventually, the validity and effectiveness of the modelling and control methods are confirmed by the experimental results.
APA, Harvard, Vancouver, ISO, and other styles
18

Levinas, Michael. "Transients of Attack and Hybrid Sounds: Toward a New Mixity." Leonardo Music Journal 4 (1994): 13. http://dx.doi.org/10.2307/1513175.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

von Pfingsten, Georg, Martin Marco Nell, and Kay Hameyer. "Hybrid simulation approaches for induction machine calculation." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 5 (September 3, 2018): 1744–54. http://dx.doi.org/10.1108/compel-01-2018-0015.

Full text
Abstract:
Purpose Induction machines for traction applications are operated at working points of high ferromagnetic saturation. Depending on the working point, a broad spectrum of harmonic frequencies appears in the magnetic flux density of induction machines. Detailed loss analysis therefore requires local and temporal highly resolved nonlinear field computation. This loss analysis can be performed in the post processing of nonlinear transient finite element simulations of the magnetic circuit. However, it takes a large number of transient simulation time steps to build up the rotor flux of the machine. Design/methodology/approach In this paper, hybrid simulation approaches that couple static FEA, transient FEA and analytic formulations to significantly decrease the number of simulation time steps to calculate the magnetic field in steady state are discussed, analyzed and compared. Findings The proposed hybrid simulation approaches drastically decrease the simulation time by shortening the transient build-up of the rotor flux. Depending on the maximum error of the rotor flux linkage amplitude compared to the steady state value, a reduction of simulation time steps in the range of 55.5 to 98 per cent is found. Originality/value The presented hybrid simulation approaches allow efficient performing of the transient FE magnetic field simulations of induction machines operated as traction drives.
APA, Harvard, Vancouver, ISO, and other styles
20

Lee, Ho-Yun, Mansoor Asif, Kyu-Hoon Park, Hyun-Min Mun, and Bang-Wook Lee. "Appropriate Protection Scheme for DC Grid Based on the Half Bridge Modular Multilevel Converter System." Energies 12, no. 10 (May 15, 2019): 1837. http://dx.doi.org/10.3390/en12101837.

Full text
Abstract:
The half bridge (HB) modular multilevel converter (MMC) technology is considered a breakthrough to mitigate the shortcomings of the conventional voltage source converter (VSC) in high-voltage direct-current (HVDC) grid application. However, interruption of the DC fault is still a challenge due to fast di/dt and extremely high levels of DC fault current. The fault interruption using a DC circuit breaker (DCCB) causes enormous energy dissipation and voltage stress across the DCCB. Therefore, the use of a fault current limiter is essential, and the superconducting fault current limiter (SFCL) is the most promising choice. Past literature has focused on the operating characteristics of DCCB or limiting characteristics of the SFCL. However, there is little understanding about the fault interruption and system recovery characteristics considering both DCCB and SFCL. In this paper, we have presented a comparative study on fault interruption and system recovery characteristics considering three types of fault limiting devices in combination with circuit breaker. The transient analyses of AC and DC system have been performed, to suggest the most preferable protection scheme. It has been concluded that, amongst the three fault limiting devices, the Hybrid SFCL in combination with circuit breaker, delivers the most desirable performance in terms of interruption time, recovery time, energy dissipation and voltage transients.
APA, Harvard, Vancouver, ISO, and other styles
21

Rozegnał, Bartosz, Paweł Albrechtowicz, Dominik Mamcarz, Natalia Radwan-Pragłowska, and Artur Cebula. "The Short-Circuit Protections in Hybrid Systems with Low-Power Synchronous Generators." Energies 14, no. 1 (December 30, 2020): 160. http://dx.doi.org/10.3390/en14010160.

Full text
Abstract:
Single-phase short-circuits are most often faults in electrical systems. The analysis of this damage type is taken for backup power supply systems, from small power synchronous generators. For these hybrid installations, there is a need for standard protection devices, such as fuses or miniature circuit breaker (MCB) analysis. Experimental research mentioned that a typical protective apparatus in low-voltage installations, working correctly during supplying from the grid, does not guarantee fast off-switching, while short-circuits occur during supplication from the backup generator set. The analysis of single-phase short-circuits is executed both for current waveform character (including sub-transient and transient states) and the carried energy, to show the problems with the fuses and MCB usage, to protect circuits in installations fed in a hybrid way (from the grid and synchronous generator set).
APA, Harvard, Vancouver, ISO, and other styles
22

Debnath, N. C., and T. Roy. "Transfer scattering matrix of non-uniform surface acoustic wave transducers." International Journal of Mathematics and Mathematical Sciences 10, no. 3 (1987): 563–81. http://dx.doi.org/10.1155/s0161171287000681.

Full text
Abstract:
This paper is concerned with a general mathematical theory for finding the admittance matrix of a three-port non-uniform surface acoustic wave (SAW) network characterized bynunequal hybrid sections. The SAW interdigital transducer and its various circuit model representations are presented in some detail. The Transfer scattering matrix of a transducer consisting ofNnon-uniform sections modeled through the hybrid equivalent circuit is discussed. General expression of the scattering matrix elements for aN-section SAW network is included. Based upon hybrid equivalent circuit model of one electrode section, explicit formulas for the scattering and transfer scattering matrices of a SAW transducer are obtained. Expressions of the transfer scattering matrix elements for theN-section crossed-field and in-line model of SAW transducers are also derived as special cases. The matrix elements are computed in terms of complex frequency and thus allow for transient response determinations. It is shown that the general forms presented here for the matrix elements are suitable for the computer aided design of SAW transducers.
APA, Harvard, Vancouver, ISO, and other styles
23

Ramshaw, J. D., and G. L. Mesina. "A hybrid penalty-pseudocompressibility method for transient incompressible fluid flow." Computers & Fluids 20, no. 2 (January 1991): 165–75. http://dx.doi.org/10.1016/0045-7930(91)90018-d.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

Gondim, R. R., E. N. Macedo, and R. M. Cotta. "Hybrid solution for transient internal convection with axial diffusion." International Journal of Numerical Methods for Heat & Fluid Flow 17, no. 4 (May 22, 2007): 405–17. http://dx.doi.org/10.1108/09615530710739176.

Full text
APA, Harvard, Vancouver, ISO, and other styles
25

Chaabane, Raoudha, Faouzi Askri, and Ben Nasrallah. "A new hybrid algorithm for solving transient combined conduction radiation heat transfer problems." Thermal Science 15, no. 3 (2011): 649–62. http://dx.doi.org/10.2298/tsci100722015c.

Full text
Abstract:
A new algorithm based on the lattice Boltzmann method (LBM) and the Control Volume Finite Element Method (CVFEM) is proposed as an hybrid solver for two dimensional transient conduction and radiation heat transfer problems in an optically emitting, absorbing and scattering medium. The LBM was used to solve the energy equation and the CVFEM was used to compute the radiative information. The advantages of the proposed methodology is to avoid problems that confronted when previous techniques are used to predict radiative heat transfer, essentially, in complex geometries and when there is scattering and/or non-black boundaries surfaces. This method combination, which is applied for the first time to solve this unsteady combined mode of heat transfer, has been found to accurately predict the effects of various thermo-physical parameters such as the scattering albedo, the conduction-radiation parameter and the extinction coefficient on temperature distribution. The results of the LBM-CVFEM combination were found to be in excellent agreement with the LBM-CDM (Collapsed Dimension Method)this proposed numerical approach include, among others, simple implementation on a computer, accurate CPU time, and capability of stable simulation.
APA, Harvard, Vancouver, ISO, and other styles
26

Anyanwu, Hou, Chen, Pan, Du, Xuan, and Jiao. "Numerical Investigation of Liquid Water Transport Dynamics in Novel Hybrid Sinusoidal Flow Channel Designs for PEMFC." Energies 12, no. 21 (October 23, 2019): 4030. http://dx.doi.org/10.3390/en12214030.

Full text
Abstract:
This study numerically investigates liquid water dynamics in a novel hybrid sinusoidal flow channel of a proton exchange membrane fuel cell (PEMFC). The two-phase flow is examined using a three-dimensional, transient computational fluid dynamics (CFD) simulation employing the coupled level set and volume of fluid (VOF) method. Simulations for hybrid and non-hybrid sinusoidal flow channels, including a straight flow channel, are compared based on their water exhaust capacities and pressure drops. Additionally, the effects of inlet gas velocity, wall wettability, and droplet interaction in the flow channel on the dynamic behaviour of liquid water are investigated. Results reveal that the novel hybrid sinusoidal channel designs are consistent in terms of quicker water removal under varying hydrophilic wall conditions. Also, it is found that the liquid surface coverage, detachment, and removal rate depends on droplet proximity to the walls, inlet gas velocity, and wall contact angle. Also, the time a droplet makes contact with the side walls affect the discharge time. Additionally, there is an improvement in the gas velocity magnitude and vertical component velocity across the hybrid sinusoidal channel designs. Therefore, the unique geometric configuration of the proposed hybrid design makes it a viable substitute for water management in PEMFC applications.
APA, Harvard, Vancouver, ISO, and other styles
27

Yusop, A. M., R. Mohamed, A. Ayob, and A. Mohamed. "Dynamic Modeling and Simulation of a Thermoelectric-Solar Hybrid Energy System Using an Inverse Dynamic Analysis Input Shaper." Modelling and Simulation in Engineering 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/376781.

Full text
Abstract:
This study presents the behavioral model of thermal temperature and power generation of a thermoelectric-solar hybrid energy system exposed to dynamic transient sources. In the development of thermoelectric-solar hybrid energy system, studies have focused on the regulation of both systems separately. In practice, a separate control system affects hardware pricing. In this study, an inverse dynamic analysis shaping technique based on exponential function is applied to a solar array (SA) to stabilize output voltage before this technique is combined with a thermoelectric module (TEM). This method can be used to estimate the maximum power point of the hybrid system by initially shaping the input voltage of SA. The behavior of the overall system can be estimated by controlling the behavior of SA, such that SA can follow the output voltage of TEM as the time constant of TEM is greater than that of SA. Moreover, by employing a continuous and differentiable function, the acquired output behavior of the hybrid system can be attained. Data showing the model is obtained from current experiments with predicted values of temperature, internal resistance, and current attributes of TEM. The simulation results show that the proposed input shaper can be used to trigger the output voltage of SA to follow the TEM behavior under transient conditions.
APA, Harvard, Vancouver, ISO, and other styles
28

Gudiño-Mendoza, Berenice, Ernesto López-Mellado, and Hassane Alla. "Modeling and simulation of water distribution systems using timed hybrid Petri nets." SIMULATION 88, no. 3 (January 19, 2011): 329–47. http://dx.doi.org/10.1177/0037549710388749.

Full text
Abstract:
This paper deals with modeling and simulation of water distribution systems using Hybrid Petri Nets. A methodology for building a Timed Hybrid Petri Net (THPN) model is proposed; the model is derived from a set of equations describing conservation of mass and energy that specify the behaviour of a water distribution network. A simulation technique for the execution of a THPN in which the transitions firing velocities are established from the linearised conservation of energy equations is presented; it shows both transient and steady state for the analysis of hydraulic networks. Based on this technique, a simulator in Matlab has been developed.
APA, Harvard, Vancouver, ISO, and other styles
29

Tamma, Kumar, and Sudhir Railkar. "Hybrid Transfinite Element Methodology for Nonlinear Transient Thermal Problems." Numerical Heat Transfer, Part B: Fundamentals 11, no. 4 (1987): 443–59. http://dx.doi.org/10.1080/10407798708552556.

Full text
APA, Harvard, Vancouver, ISO, and other styles
30

Zhou, Junyang, and Michael A. Adewumi. "Simulation of transients in natural gas pipelines using hybrid TVD schemes." International Journal for Numerical Methods in Fluids 32, no. 4 (February 29, 2000): 407–37. http://dx.doi.org/10.1002/(sici)1097-0363(20000229)32:4<407::aid-fld945>3.0.co;2-9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

Lencwe, Mpho, Shyama Chowdhury, and Thomas Olwal. "A Multi-Stage Approach to a Hybrid Lead Acid Battery and Supercapacitor System for Transport Vehicles." Energies 11, no. 11 (October 24, 2018): 2888. http://dx.doi.org/10.3390/en11112888.

Full text
Abstract:
Lead Acid Batteries (LABs) are used for starting, lighting, and igniting, as well as in air conditioning systems and to supply power to electric engines in transport vehicles (TVs). However, the application of LABs for TVs has faced a number of market challenges, mounted by the upcoming high energy density and long lifespan batteries, such as lithium ion. LABs, on the other hand, are inexpensive. The key research question is, how can the lifespan of LABs used in automotive industries be increased, while still ensuring a low cost solution? Thus, integrating LABs with the supercapacitor (known as an electric double layer capacitor—EDLC) is likely to outperform the competing alternative batteries for TVs. This paper proposes a multiple stage approach to hybrid lead acid batteries and a supercapacitor system for TVs that is capable of maintaining the battery state-of-charge (SOC) at statistically high limits, ranging between 90% and 95%. This SOC target will likely ensure that the lifespan of the hybrid battery system can be elongated (extended) more than its competitors. In this study, the multiple stage approach of concatenated converters has been designed in order to satisfy all energy storage requirements for different characteristics of LABs and the supercapacitor. The designed hybrid system has been simulated using Matrix Laboratory (MATLAB/Simulink (version R2016a, MathWorks, Natick, MA, USA)). The simulated results show that high transient currents from the direct current (DC) bus of LABs, caused by the regenerative braking or deceleration of the TVs, reduce the battery lifespan and induce mechanical stress. The supercapacitor reduces the stress on the LAB by absorbing high transient currents. This, in turn, keeps the LABs’ SOC between 90% and 96% and the voltage at 12 V. As indicated by the simulated results, the hybrid battery SOC is maintained at 90–96% and the terminal voltage is approximately 12 V.
APA, Harvard, Vancouver, ISO, and other styles
32

Ma, Ceyi, Yinghong Wen, and Jinbao Zhang. "A Fast, Hybrid, Time-Domain Discontinuous Galerkin-Physical Optics Method for Composite Electromagnetic Scattering Analysis." Applied Sciences 11, no. 6 (March 17, 2021): 2694. http://dx.doi.org/10.3390/app11062694.

Full text
Abstract:
To accelerate the solution of transient electromagnetic scattering from composite scatters, a novel hybrid discontinuous Galerkin time domain (DGTD) and time-domain physical optics (TDPO) method is proposed. The DGTD method is used to solve the accurate scattering field of the multi-scale objects region, and a hybrid explicit-implicit time integration method is also used to improve the efficiency of multi-scale problems in the time domain. Meanwhile, the TDPO method is used to accelerate the speed of surface current integration in an electrically large region. In addition, the DGTDPO method considers the mutual coupling between two regions, and effectively reduces the number of numerical calculations for the other space of the composite target, thereby significantly reducing the computer memory consumption. Numerical results certified the high efficiency and accuracy of the hybrid DGTDPO. According to the results, in comparison with the DGTD algorithm in the entire computational domain, the DGTDPO method can reduce computing time and memory by 90% and 70% respectively. Meanwhile, the normalized root mean square deviation (NRMSD) of the time-domain, high-frequency approximation method is over 0.2, and that of the DGTDPO method is only 0.0971. That is, compared with the approximation methods, the hybrid method improves the accuracy by more than 64%.
APA, Harvard, Vancouver, ISO, and other styles
33

Gherairi, Salsabil. "Hybrid Electric Vehicle: Design and Control of a Hybrid System (Fuel Cell/Battery/Ultra-Capacitor) Supplied by Hydrogen." Energies 12, no. 7 (April 2, 2019): 1272. http://dx.doi.org/10.3390/en12071272.

Full text
Abstract:
Due to its high efficiency and reduced emissions, new zero-emission hybrid electric vehicles have been selected as an attractive challenge for future transport applications. New zero -emission hybrid electric, on the other hand, has some major drawbacks from the complicated charging process. The hybrid electrical fuel cell system is introduced as the main source to intelligently control multi-source activities. An ultra-capacitor system is selected as the energy recovery assistance to monitor the fuel cell’s fast transient and peak power during critical periods. To regulate energy demand and supply, an intelligent energy management system is proposed and tested through several constraints. The proposed approach system aims to act quickly against sudden circumstances related to hydrogen depletion in the prediction of the required fuel consumption basis. The proposed strategy tends to define the proper operating system according to energy demand and supply. The obtained results show that the designed system meets the targets set for the energy management unit by referring to an experimental velocity database.
APA, Harvard, Vancouver, ISO, and other styles
34

Ifis, A., F. Bilteryst, and M. Nouari. "Transient thermomechanical analysis of thin layers using a hybrid “MAX-FEM” model." Finite Elements in Analysis and Design 69 (July 2013): 73–87. http://dx.doi.org/10.1016/j.finel.2013.01.008.

Full text
APA, Harvard, Vancouver, ISO, and other styles
35

Joelianto, Endra, and Darrell Williamson. "Transient response improvement of feedback control systems using hybrid reference control." International Journal of Control 82, no. 10 (August 6, 2009): 1955–70. http://dx.doi.org/10.1080/00207170902866120.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

Hathout, J. P., and A. El-Shafei. "PI Control of HSFDs for Active Control of Rotor-Bearing Systems." Journal of Engineering for Gas Turbines and Power 119, no. 3 (July 1, 1997): 658–67. http://dx.doi.org/10.1115/1.2817035.

Full text
Abstract:
This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDS) for active control of rotor vibrations. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady-state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient runup through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated into the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.
APA, Harvard, Vancouver, ISO, and other styles
37

Clark, Robert L. "A Hybrid Autonomous Control Approach." Journal of Dynamic Systems, Measurement, and Control 117, no. 2 (June 1, 1995): 232–40. http://dx.doi.org/10.1115/1.2835184.

Full text
Abstract:
A hybrid autonomous control approach for active damping and control of a persistent disturbance is presented. Direct velocity feedback control is coupled with an adaptive feedforward controller to minimize the transient response and that due to a persistent disturbance, respectively. A time-averaged gradient descent algorithm was selected to adapt the feedforward filter, rendering the controller model-insensitive and thus autonomous for the chosen application. The feedback control loop serves to increase the damping of the controlled structure, decreasing the convergence time associated with the adaptive feedforward filter. Thus the integration of the two control approaches affords increases in performance previously not possible with the adaptive feedforward controller alone.
APA, Harvard, Vancouver, ISO, and other styles
38

Hwang, Sungchul, Sungyoon Song, Gilsoo Jang, and Minhan Yoon. "An Operation Strategy of the Hybrid Multi-Terminal HVDC for Contingency." Energies 12, no. 11 (May 28, 2019): 2042. http://dx.doi.org/10.3390/en12112042.

Full text
Abstract:
The application of the direct current (DC) transmission is increasing through the interconnection between grids or the renewable energy resource integration. Various types of DC transmission topology are researched, and the hybrid multi-terminal high voltage DC (HVDC), called the “MTDC”, is one of the research subjects. The hybrid multi-terminal HVDC is the MTDC system that is composed with the Line Commutated Converter (LCC) and Voltage Source Converter (VSC). Most hybrid MTDC research has been focused on the connection of the renewable energy generation sources, especially offshore wind farms. However, the DC grid built with a hybrid MTDC was recently proposed due to the development of the converter technology. Therefore, the DC grid is expected to be able to substitute some parts of the transmission grid instead of the alternating current (AC) system, and the operation strategies of the DC grid are still being researched. The DC grid has the advantage of being able to control the power flow, which can even improve the stability of the connected AC system. The dynamic model is required to analyze the improvement of the AC system by the operation strategy of the hybrid MTDC, however, there is no generic model for the system. In this paper, an operation strategy of the hybrid MTDC is proposed to improve the stability of the AC power system by increasing the utilization of parallel AC transmission lines under the contingency condition. Furthermore, studies on the modeling method for a hybrid MTDC analysis were performed. The proposed modeling method and operation strategy were verified in simulations for which a modified IEEE 39 bus test system was used. The improvement of transient stability by the proposed hybrid MTDC system was shown in the simulation results.
APA, Harvard, Vancouver, ISO, and other styles
39

Sun, Dong Mei, and Jun Wen. "Researches on Reactive Compensation for Long-Distance and Highcapacity Hybrid Submarine Cable Lines." Advanced Materials Research 433-440 (January 2012): 2406–10. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.2406.

Full text
Abstract:
In order to balance reactive power, reduce line losses, prevent excessive power frequency and switching over-voltage and adjust and control the line voltage etc. The long-distance and high voltage transmission lines are needed reactive power compensation. High voltage overhead transmission lines and high voltage submarine cable (including mixed-submarine) transmission lines are different, for example, the capacitance in the submarine cable lines is larger than in the conventional overhead lines. Therefore, the reactive power compensation on the EHV transmission lines which contains submarine cable lines is focus on the compensation of submarine cable lines. The reactive power compensation in 500 kV AC submarine cable interconnection project for Hainan power grid and Guangdong power grid[1], which is the first 500 kV long-distance and high-capacity sea trails interconnection project in China and which is just completed soon, is researched by Electro-Magnetic Transient Program——PSCAD/EMTDC (Power System Computer Aided Design/ Electro Magnetic Transient in DC System in this paper). The simulation results verifies that the role of shunt reactor which could absorb charging power and suppress the power frequency overvoltage for the long-distance and high-capacity hybrid submarine cable lines. The conclusions can offer references to suppress power frequency overvoltage and the reactive power compensation in extra high voltage transmission lines which is the mixed mode of overhead transmission lines and submarine cables.
APA, Harvard, Vancouver, ISO, and other styles
40

Zhou, Yue, Hussein Obeid, Salah Laghrouche, Mickael Hilairet, and Abdesslem Djerdir. "A Disturbance Rejection Control Strategy of a Single Converter Hybrid Electrical System Integrating Battery Degradation." Energies 13, no. 11 (June 1, 2020): 2781. http://dx.doi.org/10.3390/en13112781.

Full text
Abstract:
In order to improve the durability and economy of a hybrid power system composed of a battery and supercapacitors, a control strategy that can reduce fluctuations of the battery current is regarded as a significant tool to deal with this issue. This paper puts forwards a disturbance rejection control strategy for a hybrid power system taking into account the degradation of the battery. First, the degradation estimation of the battery is done by the model-driven method based on the degradation model and Cubature Kalman Filter (CKF). Considering the transient and sinusoidal disturbance from the load in such a hybrid system, it is indispensable to smooth the behavior of the battery current in order to ensure the lifespan of the battery. Moreover, the constraints for the hybrid system should be considered for safety purposes. In order to deal with these demands, a cascaded voltage control loop based on a super twisting controller and proportional integral controller with an anti-windup scheme is designed for regulating the DC bus voltage in an inner voltage loop and supercapacitors’ voltage in an outer voltage loop, respectively. The specific feature of the proposed control method is that it operates like a low-pass filter so as to reduce the oscillations on the DC bus.
APA, Harvard, Vancouver, ISO, and other styles
41

Sami, Benslama, Nasri Sihem, Salsabil Gherairi, and Cherif Adnane. "A Multi-Agent System for Smart Energy Management Devoted to Vehicle Applications: Realistic Dynamic Hybrid Electric System Using Hydrogen as a Fuel." Energies 12, no. 3 (February 1, 2019): 474. http://dx.doi.org/10.3390/en12030474.

Full text
Abstract:
Real-time simulation test beds for new zero-emission hybrid electric vehicles are considered as an attractive challenge for future transport applications that are fully recommended in the laboratory environment. In contrast, new zero-emission hybrid electric vehicles have a more complicated charging procedure. For this reason, an efficient simulation tools development for hydrogen consumption control becomes critical. In this vein, a New Zero Emission Hybrid Electric Vehicle Simulation (NZE-HEVSim) tool for the dynamic Fuel Cell Hybrid-Electric System is proposed to smartly control multisource activities. The designed system consists of a proton-exchange membrane fuel cell used to provide the required energy demand and a Supercapacitor system for energy recovery assistance in load peak or in fast transient. To regulate the supplied power, an efficient Real-Time Embedded Intelligent Energy Management (RT-EM-IEM) is implemented and tested through various constraints. The proposed intelligent energy management system aims to act quickly against sudden circumstances related to hydrogen depletion in the basis required fuel consumption prediction using multi-agent system (MAS). The proposed MAS strategy aims to define the proper operating agent according to energy demand and supply. The obtained results prove that the designed system meets the objectives set for RT-EM-IEM by referring to an experimental velocity database.
APA, Harvard, Vancouver, ISO, and other styles
42

Zhang, Qiufang, Zheng Shi, Ying Wang, Jinghan He, Yin Xu, and Meng Li. "Security Assessment and Coordinated Emergency Control Strategy for Power Systems with Multi-Infeed HVDCs." Energies 13, no. 12 (June 19, 2020): 3174. http://dx.doi.org/10.3390/en13123174.

Full text
Abstract:
Short-circuit faults in a receiving-end power system can lead to blocking events of the feed-in high-voltage direct-current (HVDC) systems, which may further result in system instability. However, security assessment methods based on the transient stability (TS) simulation can hardly catch the fault propagation phenomena between AC and DC subsystems. Moreover, effective emergency control strategies are needed to prevent such undesired cascading events. This paper focuses on power systems with multi-infeed HVDCs. An on-line security assessment method based on the electromagnetic transient (EMT)-TS hybrid simulation is proposed. DC and AC subsystems are modeled in EMTDC/PSCAD and PSS/E, respectively. In this way, interactions between AC and DC subsystems can be well reflected. Meanwhile, high computational efficiency is maintained for the on-line application. In addition, an emergency control strategy is developed, which coordinates multiple control resources, including HVDCs, pumped storages, and interruptible loads, to maintain the security and stability of the receiving-end system. The effectiveness of the proposed methods is verified by numerical simulations on two actual power systems in China. The simulation results indicate that the EMT-TS hybrid simulation can accurately reflect the fault propagation phenomena between AC and DC subsystems, and the coordinated emergency control strategy can work effectively to maintain the security and stability of systems.
APA, Harvard, Vancouver, ISO, and other styles
43

Naji Alhasnawi, Bilal, Basil H. Jasim, Amjad Anvari-Moghaddam, and Frede Blaabjerg. "A New Robust Control Strategy for Parallel Operated Inverters in Green Energy Applications." Energies 13, no. 13 (July 6, 2020): 3480. http://dx.doi.org/10.3390/en13133480.

Full text
Abstract:
This research work puts forward a hybrid AC/DC microgrid with renewable energy sources pertaining to consumer’s residential area for meeting the demand. Currently, the power generation and consumption have experienced key transformations. One such tendency would be integration of microgrids into the distribution network that is characterized by high penetration of renewable energy resources as well as operations in parallel. Traditional droop control can be employed in order to get an accurate steady state averaged active power sharing amongst parallel inverters pertaining to hybrid AC/DC microgrid. It is presumed that there would be similar transient average power responses, and there would be no circulating current flowing between the units for identical inverters possessing the same droop gain. However, the instantaneous power could be affected by different line impedances considerably and thus resulting in variation in circulating power that flows amongst inverters, especially during unexpected disturbances like load changes. This power, if absorbed by the inverter, could result in sudden DC-link voltage rise and trip the inverter, which in turn causes performance degradation of the entire hybrid microgrid. When the hybrid generators act as unidirectional power source, the issue worsens further. In this research work, we have put forward a new distributed coordinated control pertaining to hybrid microgrid, which can be applied for both grid connected and islanded modes that include variable loads and hybrid energy resources. Also, in order to choose the most effective controller scheme, a participation factor analysis has been designed for binding the DC-link voltage as well as reducing the circulating power. Moreover, to both photovoltaic stations and wind turbines, maximum power point tracking (MPPT) techniques have been used in order to extract the maximum power from hybrid power system when there is discrepancy in environmental circumstances. Lastly, the feasibility and effectiveness pertaining to the introduced strategy for hybrid microgrid in various modes are confirmed via simulation results.
APA, Harvard, Vancouver, ISO, and other styles
44

Li, Yunlu, Junyou Yang, Haixin Wang, Weichun Ge, and Yiming Ma. "Leveraging Hybrid Filter for Improving Quasi-Type-1 Phase Locked Loop Targeting Fast Transient Response." Energies 11, no. 9 (September 17, 2018): 2472. http://dx.doi.org/10.3390/en11092472.

Full text
Abstract:
In renewable energy generation applications, phase locked loop (PLL) is one of the most popular grid synchronization technique. The main objective of PLL is to rapidly and precisely extract phase and frequency especially when the grid voltage is under non-ideal conditions. This motivates the recent development of moving average filters (MAFs) based PLL in a quasi-type-1 system (i.e., QT1-PLL). Despite its success in certain applications, the transient response is still unsatisfactory, mainly due to the fact that the time delay caused by MAFs is still large. This has significantly limited the utilization of QT1-PLL, according to common grid codes such as German and Spanish grid codes. This challenge has been tackled in this paper. The basic idea is to develop a new hybrid filtering stage, consisting of adaptive notch filters (ANFs) and MAFs, arranged at the inner loop of QT1-PLL. Such an idea can greatly improve the transient response of QT1-PLL, owing to the fact that ANFs are utilized to remove the fundamental frequency negative voltage sequence (FFNS) component while other dominant harmonics can be removed by MAFs with a small time delay. By applying the proposed technique, the settling time is reduced to less than one cycle of grid frequency without any degradation in filtering capability. Moreover, the proposed PLL can be easily expanded to handle dc offset rejection. The effectiveness is validated by comprehensive experiments.
APA, Harvard, Vancouver, ISO, and other styles
45

Zhang, Yuhan, Guiping Du, Jiajian Li, and Yanxiong Lei. "Hybrid Control Strategy of MPC and DBC to Achieve a Fixed Frequency and Superior Robustness." Energies 13, no. 5 (March 4, 2020): 1176. http://dx.doi.org/10.3390/en13051176.

Full text
Abstract:
In this paper, a hybrid control strategy for power converters, based on improved deadbeat control (DBC) and improved finite control set model predictive control (MPC), is proposed. The presented control strategy employs a switched method to achieve a fixed switching frequency while maintaining a fast transient time. Moreover, the proposal incorporates error correction to achieve superior robustness. A prototype of a single-phase voltage source rectifier is established to verify the performance of the proposal. The comparative results with conventional MPC are given and illustrate the merits of the proposed control method.
APA, Harvard, Vancouver, ISO, and other styles
46

Hirani, H., K. Athre, and S. Biswas. "A Hybrid Solution Scheme for Performance Evaluation of Crankshaft Bearings." Journal of Tribology 122, no. 4 (February 8, 2000): 733–40. http://dx.doi.org/10.1115/1.1286271.

Full text
Abstract:
In the past few decades the research efforts towards efficient solutions of crankshaft bearing using both rapid (e.g., analytical, semi-analytical, curve fits) and rigorous numerical approaches have made sufficient progress. Analytical solutions compromise on accuracy. In contrast numerical methods require very high computational time and facilities with large memory requirements. These features make it very difficult to obtain a solution that is optimal with respect to memory requirements, computational speed and accuracy. Therefore, here a hybrid procedure for thermal analysis of crankshaft bearings is attempted, which uses a combination of both the analytical and numerical solution techniques. Operational parameters such as journal velocity and effective viscosity are calculated with reasonable accuracy using analytical method. Other parameters such as maximum pressure, oil-flow, and power loss are evaluated by numerical technique. Experiments to validate the proposed hybrid procedure are performed, by developing a test rig that simulates the speed and load conditions usually encountered in practice. A number of experiments at different speeds and loads are performed to check the reliability of the global energy balance (based on effective viscosity assumption) in dynamically loaded bearing. The hybrid methodology is described by a flow chart and can conveniently be programmed on a personal computer. The predictions of two crankshaft main bearings using the proposed methodology are compared with those obtained by rigorous transient thermohydrodynamic (THD) analysis. [S0742-4787(00)02103-2]
APA, Harvard, Vancouver, ISO, and other styles
47

Sadeque, Sajia, Yu Gong, Kerry Maize, Amir K. Ziabari, Amr M. S. Mohammed, Ali Shakouri, and David B. Janes. "Transient Thermal Response of Hotspots in Graphene–Silver Nanowire Hybrid Transparent Conducting Electrodes." IEEE Transactions on Nanotechnology 17, no. 2 (March 2018): 276–84. http://dx.doi.org/10.1109/tnano.2018.2794782.

Full text
APA, Harvard, Vancouver, ISO, and other styles
48

Saha, Anulekha, Aniruddha Bhattacharya, Priyanath Das, and Ajoy Kumar Chakraborty. "HSOS: a novel hybrid algorithm for solving the transient-stability-constrained OPF problem." Soft Computing 24, no. 10 (September 25, 2019): 7481–510. http://dx.doi.org/10.1007/s00500-019-04374-9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
49

Huang, Bin, Nengling Tai, and Wentao Huang. "Optimization and Coordination of HAFDV PINN Control by Improved PSO." Journal of Control Science and Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/872624.

Full text
Abstract:
The new hybrid active filter (HAF) is composed of the larger-capacity passive filter banks and the smaller-capacity active filter. It is difficult to tune the parameters of a PI controller using the DC capacitor voltage control. In this paper, the improved particle swarm optimization (improved PSO) algorithm is proposed to solve the coordinated design problem, and the neural network weights as the particle swarm optimization are adopted to optimize the system parameters. Comparing with the conventional PI controller, the results of PINN controller prove the effectiveness of designed method on both the transient and steady-state performance of the hybrid active filter DC bus voltage (HAFDV) controllers.
APA, Harvard, Vancouver, ISO, and other styles
50

Mosavi, Seyed Alireza Bashiri. "Extracting Most Discriminative Features on Transient Multivariate Time Series by Bi-Mode Hybrid Feature Selection Scheme for Transient Stability Prediction." IEEE Access 9 (2021): 121087–110. http://dx.doi.org/10.1109/access.2021.3108393.

Full text
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography