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1
Kirei, Botond Sandor, Calin-Adrian Farcas, Cosmin Chira, Ionut-Alin Ilie e Marius Neag. "Hardware Emulation of Step-Down Converter Power Stages for Digital Control Design". Electronics 12, n. 6 (10 marzo 2023): 1328. http://dx.doi.org/10.3390/electronics12061328.
Abstract (sommario):
This paper proposes a methodology of delivering the emulation hardware of several step-down converter power stages. The generalized emulator design methodology follows these steps: first, the power stage is described using an ordinary differential equation system; second, the ordinary differential equation system is solved using Euler’s method, and thus an accurate time-domain model is obtained; next, this time-domain model can be described using either general-purpose programming language (MATLAB, C, etc.) or hardware description language (VHDL, Verilog, etc.). As a result, the emulator has been created; validation of the emulator may be carried out by comparing it to SPICE transient simulations. Finally, the validated emulator can be implemented on the preferred target technology, either in a general-purpose processor or a field programmable gate array. As the emulator relies on the ordinary differential equation system of the power stage, it has better behavioral accuracy than the emulators based on average state space models. Moreover, this paper also presents the design methodology of a manually tuned proportional–integrative–derivative controller deployed on a field programmable gate array.
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Bajonero-Sandoval, David Felipe, Jeyson Sanabria-Vargas e César Leonardo Trujillo-Rodriguez. "Design and Implementation of a Low Power Wind Turbine Emulator Through the Induction Motor-Permanent Magnet Generator Arrangement". Revista Facultad de Ingeniería 29, n. 54 (1 aprile 2020): e10530. http://dx.doi.org/10.19053/01211129.v29.n54.2020.10530.
Abstract (sommario):
This paper presents the design and construction stage of a low power wind turbine emulator, which is used at the laboratory level, to reproduce different wind profiles. There are several types of wind emulators, among which the wind tunnel emulators stand out. These emulators use a motor with a propeller on their axis to obtain the desired wind speed. However, in the present work -and done from a computer- speed control is developed for a three-phase induction motor, thus driving a permanent magnet generator. The motor-generator group is controlled through a program developed in the Labview software. Also, it has the particularity of operating automatically, being able to load different speed data. Such data is associated with a particular power that takes into account the selected wind profile and can operate through manual control of the wind speed. However, this depends on the frequency given. The emulator operation is validated experimentally through two scenarios: the first one emulates the curve presented by the Eolos turbine and subsequently compares the results obtained, whereas the second one loads the wind profile of Uribía-Guajira -a region in Colombia- achieving that the emulated wind profile can be accurately seen in the loaded wind profile.
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Alaoui, Mustapha, Hattab Maker, Azeddine Mouhsen e Hicham Hihi. "Photovoltaic emulator of different solar array configurations under partial shading conditions using damping injection controller". International Journal of Power Electronics and Drive Systems (IJPEDS) 11, n. 2 (1 giugno 2020): 1019. http://dx.doi.org/10.11591/ijpeds.v11.i2.pp1019-1030.
Abstract (sommario):
In the last decades, researchers and scientists have been trending towards photovoltaic (PV) solar energy research as one of the noteworthy renewable energies. As a matter of fact, the need for a laboratory system devoted to performing measurements and experimentation on PV systems is being increased. The PV array emulator is designed to accomplish this task by reproducing accurately the electrical behavior of real PV sources. The present paper proposes thus a new control and design of PV array emulators. It is based essentially on a hybrid Damping Injection controller. The proposed control strategy circumvents obviously the existing PV emulator's limitations in terms of accuracy, speed and partial shading emulation. Several results are given and discussed to show the efficiency of the proposed system to emulate PV modules and different PV array configurations under uniform solar irradiance and partial shading conditions.
4
Moussa, Intissar, Adel Khedher e Adel Bouallegue. "Design of a Low-Cost PV Emulator Applied for PVECS". Electronics 8, n. 2 (19 febbraio 2019): 232. http://dx.doi.org/10.3390/electronics8020232.
Abstract (sommario):
Applied tests on a real photovoltaic panel for a consolidated analysis require complex experiment setup and permanent availability of climatic conditions. This method is ineffective and can damage the PV system. As a result, PV emulators are highly requested in solar energy conversion and generation research, which rests essentially on a maximum power point tracking control algorithm (MPPT) and an adapting power stage as the DC-DC converter and PV inverter. The PV emulator guarantees a controllable light source environment to act as a real PV system in the laboratory. This paper deals with the study and development of an experimental PV emulator based on logarithmic approximation of the ideal single diode model (ISDM), which is implemented using analog electronic components. Mainly, the PV model, the controller, and the power stages, forming the PV emulator, are described. This simple, low-cost, and efficient device is considered as a nonlinear power supply template replacing the real PV system for any operating point irrespective of the environmental condition changes. The emulated current-voltage and power-voltage curves are validated via resistive load and batteries. Then, the performance of the proposed PV emulator is evaluated by its ability to recharge properly two 12V 7 Ah batteries.
5
Ozawa, Felipe, Marco Rocha, Guilherme Lucas, Wallace Souza e Andre Andreoli. "Application of Torque Transducer and Rotary Encoder in a Hardware-in-the-Loop Wind Turbine Emulation". Proceedings 42, n. 1 (14 novembre 2019): 55. http://dx.doi.org/10.3390/ecsa-6-06633.
Abstract (sommario):
Wind energy is one of the most promising forms of renewable energy. For the constant evolution of power generation technology, the use of sensors is fundamental to the development of wind turbine emulators. A wind turbine emulator allows tests and evaluations of a wind power system, regardless of weather conditions. Therefore, to further improve this technology, this work focuses on the application of a torque transducer and a rotary encoder for the implementation of a closed-loop wind turbine emulator. The sensors provide the torque and speed feedback signals to the computational model so that the model could plot the power curves and produce the set point voltage used by a variable-frequency drive (VFD) to control a three-phase induction motor (TIM). The emulator was implemented using a control algorithm designed on LabVIEW, with an NI 6211 for the data acquisition. Finally, the system emulates the behaviour of a wind turbine, considering the variations in wind speed, aerodynamic phenomena, load effects, and pitch angle. Experimental results demonstrated the effectiveness of using the TIM-VFD assembly for emulating a wind turbine since the wind turbine emulator behaved like a wind turbine in real-time.
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Peskar, Jarrett, Kerry Sado, Austin Downey, Kristen Booth e Jamil Khan. "Battery Emulator for Coupled Electro-Thermo Powertrain Testing". ECS Meeting Abstracts MA2023-02, n. 7 (22 dicembre 2023): 969. http://dx.doi.org/10.1149/ma2023-027969mtgabs.
Abstract (sommario):
Approved, DCN# 543-443-23 Battery emulation systems are useful for testing and evaluating powertrain systems; but typically,only consider the electrical characteristics of a battery. Powertrains with shared cooling components/systems between batteries and power electronics would benefit from hardware-in-the-loop testing facilities that consider both the electrical and thermal aspects of energy storage. In this work a battery emulator that physically emulates both the electrical and thermal characteristics with a coupled electro-thermal powertrain testbed is demonstrated. The coupled electro-thermo model links the electrical and thermal outputs together and calculates them in real-time. The electrical model is an equivalent circuit representation of a battery making use of experimental data from tested cells. The electrical model is coupled to the thermal model through temperature-dependent parameters of the cell resistance and open circuit voltages. The thermal model is a lumped isothermal reduced order heat generation model. This model will calculate the net heat generated from the ohmic losses, entropic losses, and losses to cooling (liquid and ambient). The thermal model is coupled to the electrical model by being dependent on the cell’s state of charge and using the cell’s current and voltage outputs for its governing equations. Models are parameterized on experimental data acquired through pulsed hybrid testing. In this work, a 3.5 kWh battery pack with a discharge of 40 amps at 48 volts generating 38.4 Watts of heat is emulated in an electro-thermo powertrain testbed configured to represent an electric naval platform such as a small autonomous boat subjected to both baseline and pulsed loading. The electrical emulation is performed through a bidirectional power supply and thermal emulation through a resistive heater. The electro-thermo powertrain testbed then dissipates the emulated electrical energy through power convertors and electronic loads while the thermal energy is dissipated through a heat exchanger that also cools the power convertors. Numerical and experimental validation demonstrate that the coupled electro-thermo battery emulator is capable of accurately representing the electrical and thermal aspects of a 3.5 kWh battery. Limitations in terms of emulating batteries at higher temperatures and current draws are discussed. Effects of scaling the coupled electro-thermo battery emulator are also presented. Acknowledgment: This work was supported in part by the Office of Naval Research under contract NO. N00014-22-C-1003 DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited
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Donald-McCann, Jamie, Florian Beutler, Kazuya Koyama e Minas Karamanis. "matryoshka: halo model emulator for the galaxy power spectrum". Monthly Notices of the Royal Astronomical Society 511, n. 3 (29 gennaio 2022): 3768–84. http://dx.doi.org/10.1093/mnras/stac239.
Abstract (sommario):
ABSTRACT We present matryoshka, a suite of neural-network-based emulators and accompanying python package that have been developed with the goal of producing fast and accurate predictions of the non-linear galaxy power spectrum. The suite of emulators consists of four linear component emulators, from which fast linear predictions of the power spectrum can be made, allowing all non-linearities to be included in predictions from a non-linear boost component emulator. The linear component emulators include an emulator for the matter transfer function that produces predictions in ∼0.0004 s, with an error of ${\lt} 0.08{{\ \rm per\ cent}}$ (at 1σ level) on scales 10−4 < k < 101 h Mpc−1. In this paper, we demonstrate matryoshka by training the non-linear boost component emulator with analytic training data calculated with Halofit, which has been designed to replicate training data that would be generated using numerical simulations. Combining all the component emulator predictions we achieve an accuracy of ${\lt} 0.75{{\ \rm per\ cent}}$ (at 1σ level) when predicting the real space non-linear galaxy power spectrum on scales 0.0025 < k < 1 h Mpc−1. We use matryoshka to investigate the impact of the analysis set-up on cosmological constraints by conducting several full shape analyses of the real-space galaxy power spectrum. Specifically we investigate the impact of the minimum scale (or kmax), finding an improvement of ∼1.8× in the constraint on σ8 by pushing kmax from 0.25 to 0.85 h Mpc−1, highlighting the potential gains when using clustering emulators such as matryoshka in cosmological analyses.
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Agyekum, Ephraim Bonah, Seepana PraveenKumar, Aleksei Eliseev e Vladimir Ivanovich Velkin. "Design and Construction of a Novel Simple and Low-Cost Test Bench Point-Absorber Wave Energy Converter Emulator System". Inventions 6, n. 1 (22 marzo 2021): 20. http://dx.doi.org/10.3390/inventions6010020.
Abstract (sommario):
This paper proposed a test bench device to emulate or simulate the electrical impulses of a wave energy converter (WEC). The objective of the study is to reconstruct under laboratory conditions the dynamics of a WEC in the form of an emulator to assess the performance, which, in this case, is the output power. The designed emulator device is programmable, which makes it possible to create under laboratory conditions the operating mode of the wave generator, identical to how the wave generator would work under real sea conditions. Any control algorithm can be executed in the designed emulator. In order to test the performance of the constructed WEC emulator, an experiment was conducted to test its power output against that of a real point-absorber WEC. The results indicate that, although the power output for that of the real WEC was higher than the WEC emulator, the emulator performed perfectly well. The relatively low power output of the emulator was because of the type of algorithm that was written for the emulator, therefore increasing the speed of the motor in the algorithm (code) would result in higher output for the proposed WEC emulator.
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Zauner, Michael, Philipp Mandl, Oliver König, Christoph Hametner e Stefan Jakubek. "Stability analysis of a flatness-based controller driving a battery emulator with constant power load". at - Automatisierungstechnik 69, n. 2 (30 gennaio 2021): 142–54. http://dx.doi.org/10.1515/auto-2020-0107.
Abstract (sommario):
Abstract This contribution deals with the control of a battery emulator used in automotive testbeds for electric drivetrains. The battery emulator, which is realized as a DC-DC converter, is connected to a unit-under-test (UUT), e. g., an electric motor inverter. To accurately emulate the dynamic impedance of a battery, a highly dynamic output is required. Additionally, battery emulators should be applicable for a large variety of UUTs, hence robust performance in a large operating range is also required. This is especially challenging when the UUT behaves like a constant power load, as this can cause stability issues. To meet the requirements, a flatness-based control concept is presented that establishes feedback equivalence between a nonlinear and a linearized system representation. By examining the stability of the concept, an estimation of the region of attraction is found.
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Ma, Chao-Tsung, Zhen-Yu Tsai, Hung-Hsien Ku e Chin-Lung Hsieh. "Design and Implementation of a Flexible Photovoltaic Emulator Using a GaN-Based Synchronous Buck Converter". Micromachines 12, n. 12 (20 dicembre 2021): 1587. http://dx.doi.org/10.3390/mi12121587.
Abstract (sommario):
In order to efficiently facilitate various research works related to power converter design and testing for solar photovoltaic (PV) generation systems, it is a great merit to use advanced power-converter-based and digitally controlled PV emulators in place of actual PV modules to reduce the space, cost, and time to obtain the required scenarios of solar irradiances for various functional tests. This paper presents a flexible PV emulator based on gallium nitride (GaN), a wide-bandgap (WBG) semiconductor, and a based synchronous buck converter and controlled with a digital signal processor (DSP). With the help of GaN-based switching devices, the proposed emulator can accurately mimic the dynamic voltage-current characteristics of any PV module under normal irradiance and partial shading conditions. With the proposed PV emulator, it is possible to closely emulate any PV module characteristic both theoretically, based on manufacturer’s datasheets, and experimentally, based on measured data from practical PV modules. A curve fitting algorithm is used to handle the real-time generation of control signals for the digital controller. Both simulation with computer software and implementation on 1 kW GaN-based experimental hardware using Texas Instruments DSP as the controller have been carried out. Results show that the proposed emulator achieves efficiency as high as 99.05% and exhibits multifaceted application features in tracking various PV voltage and current parameters, demonstrating the feasibility and excellent performance of the proposed PV emulator.
11
Arico', Giovanni, Raul Angulo e Matteo Zennaro. "Accelerating Large-Scale-Structure data analyses by emulating Boltzmann solvers and Lagrangian Perturbation Theory". Open Research Europe 1 (15 giugno 2022): 152. http://dx.doi.org/10.12688/openreseurope.14310.2.
Abstract (sommario):
The linear matter power spectrum is an essential ingredient in all theoretical models for interpreting large-scale-structure observables. Although Boltzmann codes such as CLASS or CAMB are very efficient at computing the linear spectrum, the analysis of data usually requires 104-106 evaluations, which means this task can be the most computationally expensive aspect of data analysis. Here, we address this problem by building a neural network emulator that provides the linear theory (total and cold) matter power spectrum in about one millisecond with ≈0.2%(0.5%) accuracy over redshifts z ≤ 3 (z ≤ 9), and scales10-4 ≤ k [h Mpc-1] < 50. We train this emulator with more than 200,000 measurements, spanning a broad cosmological parameter space that includes massive neutrinos and dynamical dark energy. We show that the parameter range and accuracy of our emulator is enough to get unbiased cosmological constraints in the analysis of a Euclid-like weak lensing survey. Complementing this emulator, we train 15 other emulators for the cross-spectra of various linear fields in Eulerian space, as predicted by 2nd-order Lagrangian Perturbation theory, which can be used to accelerate perturbative bias descriptions of galaxy clustering. Our emulators are specially designed to be used in combination with emulators for the nonlinear matter power spectrum and for baryonic effects, all of which are publicly available at http://www.dipc.org/bacco.
12
Arico', Giovanni, Raul Angulo e Matteo Zennaro. "Accelerating Large-Scale-Structure data analyses by emulating Boltzmann solvers and Lagrangian Perturbation Theory". Open Research Europe 1 (16 dicembre 2021): 152. http://dx.doi.org/10.12688/openreseurope.14310.1.
Abstract (sommario):
The linear matter power spectrum is an essential ingredient in all theoretical models for interpreting large-scale-structure observables. Although Boltzmann codes such as CLASS or CAMB are very efficient at computing the linear spectrum, the analysis of data usually requires 104-106 evaluations, which means this task can be the most computationally expensive aspect of data analysis. Here, we address this problem by building a neural network emulator that provides the linear theory (total and cold) matter power spectrum in about one millisecond with ≈0.2%(0.5%) accuracy over redshifts z ≤ 3 (z ≤ 9), and scales10-4 ≤ k [h Mpc-1] < 50. We train this emulator with more than 200,000 measurements, spanning a broad cosmological parameter space that includes massive neutrinos and dynamical dark energy. We show that the parameter range and accuracy of our emulator is enough to get unbiased cosmological constraints in the analysis of a Euclid-like weak lensing survey. Complementing this emulator, we train 15 other emulators for the cross-spectra of various linear fields in Eulerian space, as predicted by 2nd-order Lagrangian Perturbation theory, which can be used to accelerate perturbative bias descriptions of galaxy clustering. Our emulators are specially designed to be used in combination with emulators for the nonlinear matter power spectrum and for baryonic effects, all of which are publicly available at http://www.dipc.org/bacco.
13
Yodwong, Burin, Damien Guilbert, Melika Hinaje, Matheepot Phattanasak, Wattana Kaewmanee e Gianpaolo Vitale. "Proton Exchange Membrane Electrolyzer Emulator for Power Electronics Testing Applications". Processes 9, n. 3 (10 marzo 2021): 498. http://dx.doi.org/10.3390/pr9030498.
Abstract (sommario):
This article aims to develop a proton exchange membrane (PEM) electrolyzer emulator. This emulator is realized through an equivalent electrical scheme. It allows taking into consideration the dynamic operation of PEM electrolyzers, which is generally neglected in the literature. PEM electrolyzer dynamics are reproduced by the use of supercapacitors, due to the high value of the equivalent double-layer capacitance value. Steady-state and dynamics operations are investigated in this work. The design criteria are addressed. The PEM electrolyzer emulator is validated by using a 400-W commercial PEM electrolyzer. This emulator is conceived to test new DC-DC converters to supply the PEM ELs and their control as well, avoiding the risk to damage a real electrolyzer for experiment purposes. The proposed approach is valid both for a single cell and for the whole stack emulation.
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Sirisukprasert, Siriroj, e Trin Saengsuwan. "A Novel Power Electronics-Based Fuel Cell Emulator". ECTI Transactions on Electrical Engineering, Electronics, and Communications 7, n. 2 (2 febbraio 2009): 63–71. http://dx.doi.org/10.37936/ecti-eec.200972.171895.
Abstract (sommario):
This paper proposes a prototype of a new power electronics-based fuel cell emulator. It can effectively replace a real electrochemical fuel cell stack during the development stage of a fuel-cell based power generation. The power stage of this new fuel cell emulator consists of a current source converter (buck rectifier) and a dc-to-dc buck converter. The research mainly focuses on emulating the electrical behavior of two well-known fuel cell systems: Proton Exchange Membrane (PEM) and Solid Oxide fuel cells. A 1.5kW PEM fuel cell case is presented inthis paper. Analysis, modeling and control strategy are presented. A hybrid control technique and a new voltage-current curve tracking technique have been proposed. Both static and dynamic performances of the proposed fuel cell emulator are experimentally verified. The results show that the proposed system can effectively perform in all three operation regions,i.e. activation, ohmic and concentration. With the collaboration of the power electronics circuits and the DSP-based controller, the proposed fuel cell emulator provides both precisely emulated voltage-current characteristic and high-quality output voltage and current.
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Ahmed, Mostafa, Ibrahim Harbi, Ralph Kennel e Mohamed Abdelrahem. "Maximum Power Point Tracking Implementation under Partial Shading Conditions Using Low-Cost Photovoltaic Emulator". Eng 3, n. 4 (27 ottobre 2022): 424–38. http://dx.doi.org/10.3390/eng3040031.
Abstract (sommario):
Maximum power point tracking (MPPT) is a pivotal objective for photovoltaic (PV) systems. To test various MPPT techniques, a reliable and effective PV emulator is required. Therefore, this article proposes a low-cost PV emulator for partial shading conditions, in which a cascaded structure of a DC power source with a resistor is constructed to generate the multiple peaks of the power-voltage (P-V) curve. The proposed structure is simple and modular. Consequently, it can be extended to obtain several peaks in the P-V characteristics to emulate more complex partial shading conditions. The partial shading occurrence over the PV source (PV array) causes a significant power loss production from the PV system. To increase the PV system’s efficiency, optimization techniques are employed to harness the global power. Accordingly, the particle swarm optimization (PSO) technique is used to track the global peak. Furthermore, the conventional perturb and observe (P&O) method is applied for comparison and investigation. The proposed PV emulation system is validated under different operating conditions using simulation and experimental hardware-in-the-loop (HIL) results.
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Sarojini, Ratnam Kamala, Kaliannan Palanisamy e Enrico De Tuglie. "A Fuzzy Logic-Based Emulated Inertia Control to a Supercapacitor System to Improve Inertia in a Low Inertia Grid with Renewables". Energies 15, n. 4 (12 febbraio 2022): 1333. http://dx.doi.org/10.3390/en15041333.
Abstract (sommario):
The contribution of power generation from converter-dominated renewable energy sources (RES) has increased enormously. Consequently, the system inertia is decreasing, and it impacts the frequency of the system. With large-scale integration of power electronic inverter-based power generation from RES, inertia from energy storage devices would be unavoidable in future power grids. In this paper, the inertia emulator is formed with a supercapacitor (IE–SC) to improve inertia in a low inertia grid. To emulate the inertia in a low inertia grid, this paper proposes a fuzzy logic controller-based emulated inertia controller (FL-EIC) for an inverter attached to IE–SC. The proposed fuzzy logic controller estimates the inertial power required based on the frequency deviation and rate of change of frequency (ROCOF). The output of the fuzzy controller adds to the conventional emulated inertia control (EIC) technique to alter the load angle for the power electronic inverter of IE–SC. Specifically, the proposed FL-EIC achieves inertia emulation by proportionally linking the time derivative of the grid frequency and frequency deviation to active power references of IE–SC. A comparison of the conventional EIC and FL-EIC is carried out to prove the effectiveness of the proposed FL-EIC. Furthermore, real-time simulations with the help of the OPAL-RT real-time simulator (OP 5700) are presented to validate the advantage of the FL-EIC.
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Tatović, Mihajlo, e Predrag B. Petrović. "Realization of a memcapacitance emulator utilizing a singular current-mode active block". Journal of Electrical Engineering 74, n. 5 (1 ottobre 2023): 390–402. http://dx.doi.org/10.2478/jee-2023-0047.
Abstract (sommario):
Abstract This paper introduces a novel circuit design for a memcapacitance emulator, employing a single Voltage Differencing Current Conveyor (VDCC) as its core element. The emulator circuit has been intricately designed, employing only capacitors as grounded passive components. One remarkable aspect of these circuits is their inherent electronic tunability, allowing for precise control of the achieved inverse memcapacitance. The theoretical analysis of the emulator includes a comprehensive examination of potential non-idealities and parasitic influences. Careful selection of passive circuit elements has been made to minimize the impact of these undesirable effects. In contrast to extant designs cataloged in the existing literature, the presented circuitry manifests remarkable simplicity in its configuration. Furthermore, it exhibits a wide operational frequency range, extending up to 50MHz, and effectively clears the non-volatility criterion. To substantiate the efficacy of the devised circuits, comprehensive LTSpice simulations have been conducted, employing a 0.18 μm TSMC process parameter and a power supply of ±0.9 V. These simulations provide robust evidence of the emulator’s performance, reaffirming the feasibility and practicality of the proposed approach in the domain of memcapacitance emulation.
18
Messo, Tuomas, Roni Luhtala, Tomi Roinila, Erik de Jong, Rick Scharrenberg, Tommaso Caldognetto, Paolo Mattavelli, Yin Sun e Alejandra Fabian. "Using High-Bandwidth Voltage Amplifier to Emulate Grid-Following Inverter for AC Microgrid Dynamics Studies". Energies 12, n. 3 (25 gennaio 2019): 379. http://dx.doi.org/10.3390/en12030379.
Abstract (sommario):
AC microgrid is an attractive way to energize local loads due to remotely located renewable generation. The AC microgrid can conceptually comprise several grid-forming and grid-following power converters, renewable energy sources, energy storage and local loads. To study the microgrid dynamics, power-hardware-in-the-loop (PHIL)-based test setups are commonly used since they provide high flexibility and enable testing the performance of real converters. In a standard PHIL setup, different components of the AC microgrid exist as real commercial devices or electrical emulators or, alternatively, can be simulated using real-time simulators. For accurate, reliable and repeatable results, the PHIL-setup should be able to capture the dynamics of the microgrid loads and sources as accurately as possible. Several studies have shown how electrical machines, dynamic RLC loads, battery storages and photovoltaic and wind generators can be emulated in a PHIL setup. However, there are no studies discussing how a three-phase grid-following power converter with its internal control functions should be emulated, regardless of the fact that grid-following converters (e.g., photovoltaic and battery storage inverters) are the basic building blocks of AC microgrids. One could naturally use a real converter to represent such dynamic load. However, practical implementation of a real three-phase converter is much more challenging and requires special knowledge. To simplify the practical implementation of microgrid PHIL-studies, this paper demonstrates the use of a commercial high-bandwidth voltage amplifier as a dynamic three-phase power converter emulator. The dynamic performance of the PHIL setup is evaluated by identifying the small-signal impedance of the emulator with various control parameters and by time-domain step tests. The emulator is shown to yield the same impedance behavior as real three-phase converters. Thus, dynamic phenomena such as harmonic resonance in the AC microgrid can be studied in the presence of grid-following converters.
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Khawaldeh, Habes. "Accurate, Fast and Power Efficient PV Emulator Based on Hybrid Passive and Active Circuits". CPSS Transactions on Power Electronics and Applications 7, n. 4 (dicembre 2022): 432–41. http://dx.doi.org/10.24295/cpsstpea.2022.00039.
Abstract (sommario):
A photovoltaic emulator (PVE) has been proposed based on a physical equivalent photovoltaic cell model. It has fast dynamic performance that is compatible with a real PV system. The PV emulator can analyze and assess PV systems, including maximum power point tracking (MPPT). It is power efficient at the maximum power point. However, it has higher power loss at an open-circuit voltage (OCV). This paper, therefore, presents a hybrid solution using a switching circuit (SC) paralleled with the diode string (DS) to minimize the power loss. The SC consists of a two-switch non-inverting buck-boost dc/dc converter. The DS operates with a low power loss region, i.e., the current source region (CSR) of the I-V curve, in which the SC switches in to replace the DS in the voltage source region (VSR) to minimize power loss of the DS while maintaining the emulator’s circuit operation. The SC handles only a fraction of the rated emulator power and has a much narrower control bandwidth than a pure switching converter-based solution. Experimental results show that in the worst-case scenario, i.e., OCV condition, the efficiency and temperature of the PVE based on DS alone configuration reach 2.8% and 94.2 °C, respectively, as compared to 85.98% and 26.5 °C for the proposed hybrid solution. Under the 30% to 60% insolation change test, the suggested PV emulator lags the actual PV panel by only 3.2 ms, compared to 120 ms lagging for a commercial emulator. Furthermore, the control strategy is implemented to handle the trade-off between thermal and dynamic performances of the proposed solution.
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Aricò, Giovanni, Raul E. Angulo, Sergio Contreras, Lurdes Ondaro-Mallea, Marcos Pellejero-Ibañez e Matteo Zennaro. "The BACCO simulation project: a baryonification emulator with neural networks". Monthly Notices of the Royal Astronomical Society 506, n. 3 (29 luglio 2021): 4070–82. http://dx.doi.org/10.1093/mnras/stab1911.
Abstract (sommario):
ABSTRACT We present a neural network emulator for baryonic effects in the non-linear matter power spectrum. We calibrate this emulator using more than 50 000 measurements in a 15D parameter space, varying cosmology and baryonic physics. Baryonic physics is described through a baryonification algorithm, which has been shown to accurately capture the relevant effects on the power spectrum and bispectrum in state-of-the-art hydrodynamical simulations. Cosmological parameters are sampled using a cosmology-rescaling approach including massive neutrinos and dynamical dark energy. The specific quantity we emulate is the ratio between matter power spectrum with baryons and gravity only, and we estimate the overall precision of the emulator to be $2\!-\!3{{\ \rm per\ cent}}$, at scales $k \lt 5 \, h\, {\rm Mpc}^{-1}$ and redshifts 0 < z < 1.5. We obtain an accuracy of $1\!-\!2{{\ \rm per\ cent}}$, when testing the emulator against a collection of 74 different cosmological hydrodynamical simulations and their respective gravity-only counterparts. We also show that only one baryonic parameter, namely Mc, which sets the gas fraction retained per halo mass, is enough to have accurate predictions of most of the baryonic feedbacks at a given epoch. Our emulator is publicly available at http://www.dipc.org/bacco.
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Brando, Guilherme, Bartolomeo Fiorini, Kazuya Koyama e Hans A. Winther. "Enabling matter power spectrum emulation in beyond-ΛCDM cosmologies with COLA". Journal of Cosmology and Astroparticle Physics 2022, n. 09 (1 settembre 2022): 051. http://dx.doi.org/10.1088/1475-7516/2022/09/051.
Abstract (sommario):
Abstract We compare and validate COLA (COmoving Lagrangian Acceleration) simulations against existing emulators in the literature, namely Bacco and Euclid Emulator 2. Our analysis focuses on the non-linear response function, i.e., the ratio between the non-linear dark matter power spectrum in a given cosmology with respect to a pre-defined reference cosmology, which is chosen to be the Euclid Emulator 2 reference cosmology in this paper. We vary three cosmological parameters, the total matter density, the amplitude of the primordial scalar perturbations and the spectral index. By comparing the COLA non-linear response function with those computed from each emulator in the redshift range 0 ≤ z ≤ 3, we find that the COLA method is in excellent agreement with the two emulators for scales up to k ∼ 1 h/Mpc as long as the deviations of the matter power spectrum from the reference cosmology are not too large. We validate the implementation of massive neutrinos in our COLA simulations by varying the sum of neutrino masses to three different values, 0.0 eV, 0.058 eV and 0.15 eV. We show that all three non-linear prescriptions used in this work agree at the 1% level at k ≤ 1 h/Mpc. We then introduce the Effective Field Theory of Dark Energy in our COLA simulations using the N-body gauge method. We consider two different modified gravity models in which the growth of structure is enhanced or suppressed at small scales, and show that the response function with respect to the change of modified gravity parameters depends weakly on cosmological parameters in these models.
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Yiu, Timothy Wing Hei, Janis Fluri e Tomasz Kacprzak. "A tomographic spherical mass map emulator of the KiDS-1000 survey using conditional generative adversarial networks". Journal of Cosmology and Astroparticle Physics 2022, n. 12 (1 dicembre 2022): 013. http://dx.doi.org/10.1088/1475-7516/2022/12/013.
Abstract (sommario):
Abstract Large sets of matter density simulations are becoming increasingly important in large-scale structure cosmology. Matter power spectra emulators, such as the Euclid Emulator and CosmicEmu, are trained on simulations to correct the non-linear part of the power spectrum. Map-based analyses retrieve additional non-Gaussian information from the density field, whether through human-designed statistics such as peak counts, or via machine learning methods such as convolutional neural networks. The simulations required for these methods are very resource-intensive, both in terms of computing time and storage. This creates a computational bottleneck for future cosmological analyses, as well as an entry barrier for testing new, innovative ideas in the area of cosmological information retrieval. Map-level density field emulators, based on deep generative models, have recently been proposed to address these challenges. In this work, we present a novel mass map emulator of the KiDS-1000 survey footprint, which generates noise-free spherical maps in a fraction of a second. It takes a set of cosmological parameters (Ω M , σ 8) as input and produces a consistent set of 5 maps, corresponding to the KiDS-1000 tomographic redshift bins. To construct the emulator, we use a conditional generative adversarial network architecture and the spherical convolutional neural network DeepSphere, and train it on N-body-simulated mass maps. We compare its performance using an array of quantitative comparison metrics: angular power spectra Cℓ , pixel/peaks distributions, Cℓ correlation matrices, and Structural Similarity Index. Overall, the average agreement on these summary statistics is <10% for the cosmologies at the centre of the simulation grid, and degrades slightly on grid edges. However, the quality of the generated maps is worse at high negative κ values or large scale, which can significantly affect summaries sensitive to such observables. Finally, we perform a mock cosmological parameter estimation using the emulator and the original simulation set. We find good agreement in these constraints, for both likelihood and likelihood-free approaches. The emulator is available at tfhub.dev/cosmo-group-ethz/models/kids-cgan.
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Vinatha, U., e P. Vittal K. "Development of Wave Turbine Emulator in a Laboratory Environment". International Journal of Emerging Electric Power Systems 14, n. 4 (26 luglio 2013): 363–72. http://dx.doi.org/10.1515/ijeeps-2012-0026.
Abstract (sommario):
Abstract Wave turbine emulator (WTE) is an important equipment for developing wave energy conversion system. The emulator reflects the actual behavior of the wave turbine by reproducing the characteristics of real wave turbine without reliance on natural wave resources and actual wave turbine. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators. The emulator can be used for research applications to drive an electrical generator in a similar way as a practical wave turbine. This article presents the development of a WTE in a laboratory environment and studies on the behavior of electrical generator coupled to the emulator. The structure of a WTE consists of a PC where the characteristics of the turbine are implemented, ac drive to emulate the turbine rotor, feedback mechanism from the drive and power electronic equipment to control the drive. The feedback signal is acquired by the PC through an A/D converter, and the signal for driving the power electronic device comes from the PC through a D/A converter.
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Díaz, Edel, Raúl Mateos, Emilio J. Bueno e Rubén Nieto. "Enabling Parallelized-QEMU for Hardware/Software Co-Simulation Virtual Platforms". Electronics 10, n. 6 (23 marzo 2021): 759. http://dx.doi.org/10.3390/electronics10060759.
Abstract (sommario):
Presently, the trend is to increase the number of cores per chip. This growth is appreciated in Multi-Processor System-On-Chips (MPSoC), composed of more cores in heterogeneous and homogeneous architectures in recent years. Thus, the difficulty of verification of this type of system has been great. The hardware/software co-simulation Virtual Platforms (VP) are presented as a perfect solution to address this complexity, allowing verification by simulation/emulation of software and hardware in the same environment. Some works parallelized the software emulator to reduce the verification times. An example of this parallelization is the QEMU (Quick EMUlator) tool. However, there is no solution to synchronize QEMU with the hardware simulator in this new parallel mode. This work analyzes the current software emulators and presents a new method to allow an external synchronization of QEMU in its parallelized mode. Timing details of the cores are taken into account. In addition, performance analysis of the software emulator with the new synchronization mechanism is presented, using: (1) a boot Linux for MPSoC Zynq-7000 (dual-core ARM Cortex-A9) (Xilinx, San Jose, CA, USA); (2) an FPGA-Linux co-simulation of a power grid monitoring system that is subsequently implemented in an industrial application. The results show that the novel synchronization mechanism does not add any appreciable computational load and enables parallelized-QEMU in hardware/software co-simulation virtual platforms.
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Balato, Marco, Annalisa Liccardo e Carlo Petrarca. "Dynamic Boost Based DMPPT Emulator". Energies 13, n. 11 (6 giugno 2020): 2921. http://dx.doi.org/10.3390/en13112921.
Abstract (sommario):
The Distributed Maximum Power Point Tracking (DMPPT) approach is a promising solution to improve the energetic performance of mismatched PhotoVoltaic (PV) systems. However, there are still several factors that can reduce DMPPT energy efficiency, including atmospheric conditions, the efficiency of the power stage, constraints imposed by the topology, the finite rating of silicon devices, and the nonoptimal value of string voltage. In order to fully explore the advantages offered by the above solution, the implementation of a Boost based DMPPT emulator is of primary concern, especially if it behaves as a controlled voltage or current source. The repeatability of experimental tests, the tighter control of climatic conditions, the closing of the gap between the physical dimensions of a PV array and the space available in a university lab, the simplicity with which new algorithms can be tested, and the low maintenance costs are just some of the benefits offered by an emulator. This paper describes the realization and use of a Boost based Distributed Maximum Power Point Tracking (DMPPT) emulator and shows its high flexibility and potential. The device is able to emulate the output current vs. voltage (I-V) characteristics of many commercial PhotoVoltaic (PV) modules with a dedicated Boost DC/DC converter. The flexibility is guaranteed by the ability to reproduce both I = f ( V ) and V = g ( I ) characteristics at different values of not only the irradiance levels but also the maximum allowed voltage across the switching devices. The system design is based on a commercial power supply controlled by a low-cost Arduino board by Arduino (Strambino, Torino, Italy). Data acquisition is performed through a low-cost current and voltage sensor by using a multichannel board by National Instruments. Experimental results confirm the capability of the proposed device to accurately emulate the output I-V characteristic of Boost based DMPPT systems obtained by varying the atmospheric conditions, the rating of silicon devices, and the electrical topology.
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Balato, Marco, Annalisa Liccardo, Carlo Petrarca e Francesco Bonavolontà. "Buck-based DMPPT emulator: a helpful experimental demonstration unit". ACTA IMEKO 10, n. 2 (29 giugno 2021): 14. http://dx.doi.org/10.21014/acta_imeko.v10i2.923.
Abstract (sommario):
<span lang="EN-GB">Distributed control strategyrepresents the most promising solution to enhance the lackluster energetic performance of mismatched PhotoVoltaic (PV) systems. Moreover, many factors that contribute to such poor performance are still to be explored. To fully understand the advantages offered by the Distributed Maximum Power Point Tracking (DMPPT) approach, the implementation of a DMPPT emulator is necessary. Based on the above needs, this paper describes the realization and use of a Buck based DMPPT emulator and shows its high flexibility and potential. The realized device is capable to emulate the output current vs. voltage (I-V) characteristics of many commercial PV modules with a dedicated Buck DC/DC converter not only in controlled atmospheric conditions but also with different currents rating of the switching devices. The system implementation is based on a commercial power supply controlled by a low-cost Arduino board. Data acquisition is performed through a low-cost current and voltage sensor by using a multichannel board by National Instruments. Experimental results confirm the validity and potential of the proposed DMPPT emulator.</span>
27
Hua, Zhi Gang, Guang Yu Hu, Zhi Gong Wu, Yong Jie Zhai e Yu Jia Huo. "A Simulation System of Wind Turbine Based on Labwindows". Applied Mechanics and Materials 530-531 (febbraio 2014): 943–51. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.943.
Abstract (sommario):
Wind energy is the worlds fastest growing renewable energy source in recent years, and it has drawn worldwide attention. Due to high efficiency, simple topology and stable operation, variable speed constant frequency (VSCF) direct-drive wind power generation system using permanent magnet synchronous generator (PMSG) is the development trend and one of the focuses of wind power generation system research. The paper introduces the trend of the development wind power generation and the recently research stage on the wind power generation. Based on the VSCF power fundamental principle, the dissertation analyzes the strategy of wind turbine simulation. In the development of wind power generating system, the wind turbine emulator becomes more and more important because it can provide controllable wind turbine characteristics. Simplified mathematical model based on the CT-λ curve is constructed, the system structure and emulation method are analyzing. Hardware and software are designed and implemented, and a laboratory set-up is building which based on DC motor. Experimental results show that the wind turbine emulator is as good as expected.
28
Zhu, Qiuming, Wei Huang, Kai Mao, Weizhi Zhong, Boyu Hua, Xiaomin Chen e Zikun Zhao. "A Flexible FPGA-Based Channel Emulator for Non-Stationary MIMO Fading Channels". Applied Sciences 10, n. 12 (17 giugno 2020): 4161. http://dx.doi.org/10.3390/app10124161.
Abstract (sommario):
In this paper, a discrete non-stationary multiple-input multiple-output (MIMO) channel model suitable for the fixed-point realization on the field-programmable gate array (FPGA) hardware platform is proposed. On this basis, we develop a flexible hardware architecture with configurable channel parameters and implement it on a non-stationary MIMO channel emulator in a single FPGA chip. In addition, an improved non-stationary channel emulation method is employed to guarantee accurate channel fading and phase, and the schemes of other key modules are also illustrated and implemented in a single FPGA chip. Hardware tests demonstrate that the output statistical properties of proposed channel emulator, i.e., the probability density function (PDF), cross-correlation function (CCF), Doppler power spectrum density (DPSD), and the power delay profile (PDP) agree well with the corresponding theoretical ones.
29
Korasiak, Przemysław, e Janusz Jaglarz. "A New Photovoltaic Emulator Designed for Testing Low-Power Inverters Connected to the LV Grid". Energies 15, n. 7 (4 aprile 2022): 2646. http://dx.doi.org/10.3390/en15072646.
Abstract (sommario):
Assessing the performance of photovoltaic systems, particularly dedicated DC/AC inverter devices, requires the use of photovoltaic panels operating under natural environmental conditions, such as variations in solar radiation intensity, temperature and wind speed. Environmental testing is obviously very troublesome, inconvenient and limited. An alternative solution is to use a device that emulates the output photovoltaic panel curves in variable weather conditions, which allows the carrying out of all necessary tests at the laboratory. This paper presents a new photovoltaic emulator (PVE), mimicking the output characteristics of the photovoltaic panels. The proposed PVE is designed and constructed at the renewable energy laboratory for testing low-power PV inverters connected to the LV grid. A novelty of this solution is the method for shaping emulated current–voltage characteristics I–V. The concept of this method assumes autonomous regulation of slopes and shapes of emulated curve fragments. This allows us to obtain the desired shapes of the output characteristics for a wide range of both voltages and currents. The proposed PVE is not a pulse device; it belongs to linear analogue circuits. In order to confirm the assumed concept, a prototype is designed and constructed, and laboratory tests are conducted. Satisfactory results are obtained, confirming the correctness of the adopted concept. High compliance of the emulated characteristics is found in comparison to the characteristics of the selected commercial photovoltaic module. Very good results of dynamic tests and energy efficiency measurements are achieved.
30
Wang, Jing, Liu Yang, Yiwei Ma, Jingxin Wang, Leon M. Tolbert, Fei Wang e Kevin Tomsovic. "Static and dynamic power system load emulation in a converter-based reconfigurable power grid emulator". IEEE Transactions on Power Electronics 31, n. 4 (aprile 2016): 3239–51. http://dx.doi.org/10.1109/tpel.2015.2448548.
31
Ghosh, Prosenjit Kumar, Shah Zayed Riam, Sharif Ahmed e Prabha Sundaravadivel. "CMOS-Based Memristor Emulator Circuits for Low-Power Edge-Computing Applications". Electronics 12, n. 7 (31 marzo 2023): 1654. http://dx.doi.org/10.3390/electronics12071654.
Abstract (sommario):
In this paper, an optimized memristor emulator circuit is designed, by using nine MOSFET transistors and a ground capacitor. Our area- and power-optimized emulator circuit can be used for basic data storage and processing at the monitoring edge, in real-time applications. The memristor shows a nonlinear voltage–current relationship, but no multiplier circuit provides the memristor’s nonlinear characteristics. As a result, the proposed memristor emulator has a very low chip area. The memristor circuit is designed in LTSpice, using 16 nm and 45 nm CMOS technology parameters, and the operating voltage is ±0.9 V. In this research, the theoretical derivations are validated using the simulated results of the memristor emulator circuit using different frequencies, capacitors, and input voltages in SPICE simulations.
32
Wang, Yuting, Ruiyang Zhao, Zhongxu Zhai, Kazuya Koyama, Will J. Percival, Hong Guo, Yin Li et al. "Emulating Power Spectra for Prereconstructed and Postreconstructed Galaxy Samples". Astrophysical Journal 966, n. 1 (24 aprile 2024): 35. http://dx.doi.org/10.3847/1538-4357/ad2e01.
Abstract (sommario):
Abstract The small-scale linear information in galaxy samples typically lost during nonlinear growth can be restored to a certain level by the density field reconstruction, which has been demonstrated for improving the precision of the baryon acoustic oscillation (BAO) measurements. As proposed in the literature, a joint analysis of the power spectrum before and after the reconstruction enables an efficient extraction of information carried by high-order statistics. However, the statistics of the postreconstruction density field are difficult to model. In this work, we circumvent this issue by developing an accurate emulator for the prereconstructed, postreconstructed, and cross-power spectra ( P pre , P post, P cross) up to k = 0.5 h Mpc−1 based on the Dark Quest N-body simulations. The accuracy of the emulator is at the percent level; namely, the error of the emulated monopole and quadrupole of the power spectra is less than 1% and 10% of the ground truth, respectively. A fit to an example power spectrum using the emulator shows that the constraints on cosmological parameters get largely improved using P pre +P post+P cross with k max = 0.25 h Mpc − 1 , compared to that derived from P pre alone; namely, the constraints on (Ω m , H 0, σ 8) are tightened by ∼41%–55%, and the uncertainties of the derived BAO and RSD parameters (α ⊥, α ∣∣, f σ 8) shrink by ∼28%–54%, respectively. This highlights the complementarity among P pre , P post, and P cross, which demonstrates the efficiency and practicability of a joint P pre , P post, and P cross analysis for cosmological implications.
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Nouri, Behnam, Ömer Göksu, Vahan Gevorgian e Poul Ejnar Sørensen. "Generic characterization of electrical test benches for AC- and HVDC-connected wind power plants". Wind Energy Science 5, n. 2 (6 maggio 2020): 561–75. http://dx.doi.org/10.5194/wes-5-561-2020.
Abstract (sommario):
Abstract. The electrical test and assessment of wind turbines go hand in hand with standards and network connection requirements. In this paper, the generic structure of advanced electrical test benches, including grid emulator or controllable grid interface, wind torque emulator, and device under test, is proposed to harmonize state-of-the-art test sites. On the other hand, modern wind turbines are under development towards new features, concerning grid-forming, black-start, and frequency support capabilities as well as harmonic stability and control interaction considerations, to secure the robustness and stability of renewable-energy-based power systems. Therefore, it is necessary to develop new and revised test standards and methodologies to address the new features of wind turbines. This paper proposes a generic test structure within two main groups, including open-loop and closed-loop tests. The open-loop tests include the IEC 61400-21-1 standard tests as well as the additional proposed test options for the new capabilities of wind turbines, which replicate grid connection compliance tests using open-loop references for the grid emulator. In addition, the closed-loop tests evaluate the device under test as part of a virtual wind power plant and perform real-time simulations considering the grid dynamics. The closed-loop tests concern grid connection topologies consisting of AC and HVDC, as well as different electrical characteristics, including impedance, short-circuit ratio, inertia, and background harmonics. The proposed tests can be implemented using available advanced test benches by adjusting their control systems. The characteristics of a real power system can be emulated by a grid emulator coupled with real-time digital simulator systems through a high-bandwidth power-hardware-in-the-loop interface.
34
Choudhury, T. Roy, A. Paranjape e B. Maity. "A GPR-based emulator for semi-numerical reionization code SCRIPT: parameter inference from 21 cm data". Journal of Cosmology and Astroparticle Physics 2024, n. 03 (1 marzo 2024): 027. http://dx.doi.org/10.1088/1475-7516/2024/03/027.
Abstract (sommario):
Abstract Semi-numerical models of reionization typically involve a large number of unknown parameters whose values are constrained by comparing with observations. Increasingly often, exploring this parameter space using semi-numerical simulations can become computationally intensive, thus necessitating the use of emulators. In this work, we present a likelihood emulator based on Gaussian Process Regression (GPR) for our semi-numerical reionization code, SCRIPT, and use it for parameter inference using mock 21 cm power spectrum data and Bayesian MCMC analysis. A unique aspect of our methodology is the utilization of coarse resolution simulations to identify high-probability regions within the parameter space, employing only a moderate amount of computational time. Samples drawn from these high-probability regions are used to construct the training set for the emulator. The subsequent MCMC using this GPR-trained emulator is found to provide parameter posteriors that agree reasonably well with those obtained using conventional MCMC. The computing time for the analysis, which includes both generation of training sets and training the emulator, is reduced by approximately an order of magnitude. This methodology is particularly advantageous in scenarios where one wants to use different parametrizations of reionization models and/or needs to start with broad prior distributions on the parameters, offering an efficient and effective means of parameter inference.
35
Qin, Rui, Chunhua Yang, Hongwei Tao, Tao Peng, Chao Yang e Zhiwen Chen. "A Power Loss Decrease Method Based on Finite Set Model Predictive Control for a Motor Emulator with Reduced Switch Count". Energies 12, n. 24 (6 dicembre 2019): 4647. http://dx.doi.org/10.3390/en12244647.
Abstract (sommario):
This paper presents a power loss decrease method based on finite set model predictive control (FSMPC) with delay compensation for a motor emulator with reduced switch count. Specifically, the topology and mathematical model of the proposed motor emulator with reduced switch count are firstly built. Secondly, in light of given instructions, the normal or fault reference current of the motor emulator is set by a reference current setter. Then delay compensation is applied for the predictive current model to calculate the current residual generated by each switch control signal, and the current tracking performance under actions of two adjacent switch control signals is evaluated for each sector. Finally, a switch power loss objective function is defined, then the two adjacent switch control signals that generate the lowest switch power loss are selected for the next second instant, which minimizes the power loss of the motor emulator with ensuring satisfied current tracking performance. Simulation and experimental results show the feasibility and effectiveness of the proposed method.
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Giblin, Benjamin, Matteo Cataneo, Ben Moews e Catherine Heymans. "On the road to per cent accuracy – II. Calibration of the non-linear matter power spectrum for arbitrary cosmologies". Monthly Notices of the Royal Astronomical Society 490, n. 4 (21 settembre 2019): 4826–40. http://dx.doi.org/10.1093/mnras/stz2659.
Abstract (sommario):
ABSTRACT We introduce an emulator approach to predict the non-linear matter power spectrum for broad classes of beyond-ΛCDM cosmologies, using only a suite of ΛCDM N-body simulations. By including a range of suitably modified initial conditions in the simulations, and rescaling the resulting emulator predictions with analytical ‘halo model reactions’, accurate non-linear matter power spectra for general extensions to the standard ΛCDM model can be calculated. We optimize the emulator design by substituting the simulation suite with non-linear predictions from the standard halofit tool. We review the performance of the emulator for artificially generated departures from the standard cosmology as well as for theoretically motivated models, such as f(R) gravity and massive neutrinos. For the majority of cosmologies we have tested, the emulator can reproduce the matter power spectrum with errors ${\lesssim}1{{\ \rm per\ cent}}$ deep into the highly non-linear regime. This work demonstrates that with a well-designed suite of ΛCDM simulations, extensions to the standard cosmological model can be tested in the non-linear regime without any reliance on expensive beyond-ΛCDM simulations.
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Marguč, Jaka, Mitja Truntič, Miran Rodič e Miro Milanovič. "FPGA Based Real-Time Emulation System for Power Electronics Converters". Energies 12, n. 6 (13 marzo 2019): 969. http://dx.doi.org/10.3390/en12060969.
Abstract (sommario):
This paper deals with an emulation system for Power Electronics Converters (PEC). The emulation of PECs is performed on a Field-Programmable Gate Array (FPGA) capable of hard real-time operation. To obtain such a system, the converter operation is described using a differential equations-based model designed with the graph theory. Differential equation coefficients are changed according to the type of converter and pulse-width modulation (PWM) signals. The tie-set and incidence matrix approach for the converter modelling is performed to describe the converter operation in a general way. Such approach enables that any type of PECs can be described appropriately. The emulator was verified experimentally by synchronous operation with a real DC-AC converter built for this purposes.
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Merenda, Massimo, Demetrio Iero, Riccardo Carotenuto e Francesco G. Della Corte. "Simple and Low-Cost Photovoltaic Module Emulator". Electronics 8, n. 12 (1 dicembre 2019): 1445. http://dx.doi.org/10.3390/electronics8121445.
Abstract (sommario):
The design and testing phase of photovoltaic (PV) power systems requires time-consuming and expensive field-testing activities for the proper operational evaluation of maximum power point trackers (MPPT), battery chargers, DC/AC inverters. Instead, the use of a PV source emulator that accurately reproduces the electrical characteristic of a PV panel or array is highly desirable for in-lab testing and rapid prototyping. In this paper, we present the development of a low-cost microcontroller-based PV source emulator, which allows testing the static and dynamic performance of PV systems considering different PV module types and variable operating and environmental conditions. The novelty of the simple design adopted resides in using a low-cost current generator and a single MOSFET converter to reproduce, from a fixed current source, the exact amount of current predicted by the PV model for the actual load conditions. The I–V characteristic is calculated in real-time using a single diode exponential model under variable and user-selectable operating conditions. The proposed method has the advantage of reducing noise from high-frequency switching, reducing or eliminating ripple and the demand for output filters, and it does not require expensive DC Power source, providing high accuracy results. The fast response of the system allows the testing of very fast MPPTs algorithms, thus overcoming the main limitations of state-of-art PV source emulators that are unable to respond to the quick variation of the load. Experimental results carried on a hardware prototype of the proposed PV source emulator are reported to validate the concept. As a whole result, an average error of ±1% in the reproduction of PV module I–V characteristics have been obtained and reported.
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Thiaux, Y., J. Seigneurbieux, B. Multon, H. Ben Ahmed e D. Miller. "Single phase AC power load profile emulator". Renewable Energy and Power Quality Journal 1, n. 06 (marzo 2008): 191–95. http://dx.doi.org/10.24084/repqj06.260.
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St. Leger, Aaron, Anthony Deese, Jeffrey Yakaski e Chika Nwankpa. "Controllable analog emulator for power system analysis". International Journal of Electrical Power & Energy Systems 33, n. 10 (dicembre 2011): 1675–85. http://dx.doi.org/10.1016/j.ijepes.2011.08.007.
41
De Bernardinis, Alexandre, Richard Lallemand e Abdelfatah Kolli. "Highly Efficient Three-Phase Bi-Directional SiC DC–AC Inverter for—Electric Vehicle Flywheel Emulator". Energies 16, n. 12 (11 giugno 2023): 4644. http://dx.doi.org/10.3390/en16124644.
Abstract (sommario):
Flywheels are nowadays a solution for the dynamic charging of electric vehicles since they act as transient energy storage. The need for a top efficient reversible power converter for the flywheel system is crucial to assure high dynamic performance. The paper presents the design of a 50 kW highly efficient reversible three-phase DC–AC inverter involving the most recent silicon carbide metal oxide semiconductor field effect transistors, and its experimental validation on a home-made emulator. Highest efficiency in reversible mode, compactness, and thermal enhancement are the targeted objectives that have been achieved. The power converter prototype evaluated on an original pulse width modulation testing-bench is able to emulate the working of the flywheel system. High frequency pulse width modulation switching, speed cycle operating, and thermal losses are evaluated. In addition, an efficiency above 99% for the converter has been attained, enabling robust functioning of the flywheel system emulator to perform specific charging profiles for electric vehicles.
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Jamieson, Drew, Yin Li, Renan Alves de Oliveira, Francisco Villaescusa-Navarro, Shirley Ho e David N. Spergel. "Field-level Neural Network Emulator for Cosmological N-body Simulations". Astrophysical Journal 952, n. 2 (25 luglio 2023): 145. http://dx.doi.org/10.3847/1538-4357/acdb6c.
Abstract (sommario):
Abstract We build a field-level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body simulation particles based on their linear inputs. Cosmology dependence is encoded in the form of style parameters at each layer of the neural network, enabling the emulator to effectively interpolate the outcomes of structure formation between different flat Lambda cold dark matter cosmologies over a wide range of background matter densities. The neural network architecture makes the model differentiable by construction, providing a powerful tool for fast field-level inference. We test the accuracy of our method by considering several summary statistics, including the density power spectrum with and without redshift space distortions, the displacement power spectrum, the momentum power spectrum, the density bispectrum, halo abundances, and halo profiles with and without redshift space distortions. We compare these statistics from our emulator with the full N-body results, the COmoving Lagrangian Acceleration (COLA) method, and a fiducial neural network with no cosmological dependence. We find that our emulator gives accurate results down to scales of k ∼ 1 Mpc−1 h, representing a considerable improvement over both COLA and the fiducial neural network. We also demonstrate that our emulator generalizes well to initial conditions containing primordial non-Gaussianity without the need for any additional style parameters or retraining.
43
Xin, Lijian, Yong Li, Hao Sun e Xiang Zhang. "OTA Testing for Massive MIMO Devices Using Cascaded APM Networks and Channel Emulators". International Journal of Antennas and Propagation 2019 (12 novembre 2019): 1–14. http://dx.doi.org/10.1155/2019/6901383.
Abstract (sommario):
This paper proposes an over-the-air (OTA) testing setup for millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) equipment using cascaded amplitude and phase modulation (APM) network and channel emulator. Compared with the existing test setup with mechanical switch, the proposed testing setup enables more accurate reconstruction of the radio channel environment under the multiprobe anechoic chamber (MPAC) setup without increasing the number of channel emulators (CEs) to control the system cost. The constructed MPAC testing setup for mmWave and massive MIMO equipment is composed of an anechoic chamber, a sectored probe wall containing a number of probes, an APM network, a fading channel emulator, and a user emulator (UE). In this paper, the structural model and the performance advantages of the proposed radiated testing setup are described, and a fully connected APM network for radiated testing is more prominent than the existing switch. Moreover, the angular spectrum is selected as the performance metric for the reconstructed channel. The ability of the proposed system to reconstruct the power angular spectrum (PAS) of the target channel is studied under both static and dynamic channel models, which can reflect the performance of beamforming procedures of the massive MIMO antenna arrays, e.g., beam acquisition, tracking, and refinement. The simulation results for angular spectrum support the superiority of the proposed OTA testing setup. Furthermore, the simulations for average channel capacity also show that radiated testing setup using cascaded APM network and channel emulator is valid.
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Ahmed, Oday A., Hussain K. Sayed, Kanaan A. Jalal, Dhari Y. Mahmood e Waleed H. Habeeb. "Design and implementation of an indoor solar emulator based low-cost autonomous data logger for PV system monitoring". International Journal of Power Electronics and Drive Systems (IJPEDS) 10, n. 3 (1 settembre 2019): 1645. http://dx.doi.org/10.11591/ijpeds.v10.i3.pp1645-1654.
Abstract (sommario):
With the growing interest in renewable energy resources, a various number of studies and development for photovoltaic (PV) systems have investigated to satisfy global needs in energy. The larger interest in PV resources has increased request for suitable apparatus with which to test PV systems. This paper deals with the design of an indoor PV source emulator using an actual PV panel to facilitate PV system testing under real environment conditions. A low-cost Arduino Mega256 microcontroller-based data acquisition system (DAQ) approach has been developed to collect the data in term of voltage, power and current based on different levels of light intensity and temperature as well as under partial shading conditions. Hence, the proposed system is not just a solar emulator but it’s a complete solar emulator-DAQ system that can emulate the sunlight and monitor the PV parameters and then collect and store the data for further research investigation. The proposed monitoring system provides real time update of the solar panel characteristics at any time in the year without relying on the weather changes. This data acquisition system will be of superior interest for undergraduate and graduate students as it is both open-source and flexible. The details design of the proposed PV solar emulator and data logger and its implementation are described.
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Zouheyr, Dekali, Baghli Lotfi e Boumediene Abdelmadjid. "Real-Time Emulation of a Grid-Connected Wind Energy Conversion System Based Double Fed Induction Generator Configuration under Random Operating Modes". European Journal of Electrical Engineering 23, n. 3 (21 giugno 2021): 207–19. http://dx.doi.org/10.18280/ejee.230305.
Abstract (sommario):
This paper presents the design, modeling, simulation and the experimental implementation of a 1.5 kW relatively low-cost wind energy conversion system (WECS) based on the double fed induction generator (DFIG) configuration. In the preliminary experiments, we test the DFIG power control under fixe speed by applying the vector control principle, then we insert the physical emulator presented in the controlled DC motor in order to simulate the static-dynamic behaviors of a real wind turbine with the use of the Tip Speed Ratio TSR based MPPT algorithm to extract the maximum available power on the emulator. The proposed structure is simulated using MATLAB Simulink environment, the obtained results are validated experimentally on our laboratory setup. We also develop an application with MATLAB AppDesigner that calculates the operating point of our system at steady state and visualize the power transfer, current, voltage and electromagnetic torque values of the DFIG and the DC motor before starting the stimulation or the experimental manipulation. The MPPT, the DC motor control and the DFIG power control algorithms are implanted in C, embedded on a dSPACE DS1104 control board. The obtained results confirm the reliability of the proposed WECS to manage all the probable operating modes, also the effectiveness of the physical simulator in the role of wind turbine emulation.
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Rajendran, Saravanakumar, Matias Diaz, V. S. Kirthika Devi, Debashisha Jena, Juan Carlos Travieso e José Rodriguez. "Wind Turbine Emulators—A Review". Processes 11, n. 3 (2 marzo 2023): 747. http://dx.doi.org/10.3390/pr11030747.
Abstract (sommario):
Renewable energy sources have become a significant alternative energy source due to the continuing depletion of conventional energy sources and fluctuation in fuel costs. Currently, wind energy is the foremost among all other renewable energy sources. However, modeling and analyzing industrial wind turbines is complex as the wind turbine power ratio and size have steadily increased. Undoubtedly, industrial wind turbines are huge and challenging to keep in research labs; simultaneously, exploring the controller/power converter performance is practically impossible. Therefore, to overcome the above drawbacks, wind turbine emulators have been developed to achieve the static and dynamic characteristics of wind energy conversion systems. This paper aims to present a comprehensive review of the different wind turbine emulators available in the literature. In addition, the implementation of real-time emulators is classified according to the structure and approaches. Furthermore, an extensive analysis of the emulators was presented based on the significant parameters utilized for the real-time wind turbine emulators. Finally, this review analyzes the different emulator topologies according to cost, accuracy, complexity, and hardware implementation.
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Ayop, Razman, Chee Wei Tan e Cheng Siong Lim. "The Resistance Comparison Method Using Integral Controller for Photovoltaic Emulator". International Journal of Power Electronics and Drive Systems (IJPEDS) 9, n. 2 (1 giugno 2018): 820. http://dx.doi.org/10.11591/ijpeds.v9.i2.pp820-828.
Abstract (sommario):
<span>A Photovoltaic (PV) emulator is a device that produces a similar output as the PV module and it is useful for testing the PV generation system. This paper present a new and simple control strategy for the PV emulator using the combination of the Resistance Comparison Method with the Integral Controller. The closed-loop buck converter system with the current-mode controlled and the single diode model are used for the PV emulator. The results obtained from the proposed PV emulator are compared with the conventional PV emulator using the Direct Referencing Method as the control strategy. The proposed PV emulator produces a more accurate output, 74 % faster transient response, and a lower output voltage ripple compared to the conventional PV emulator.</span>
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Giri, Sambit K., e Aurel Schneider. "Emulation of baryonic effects on the matter power spectrum and constraints from galaxy cluster data". Journal of Cosmology and Astroparticle Physics 2021, n. 12 (1 dicembre 2021): 046. http://dx.doi.org/10.1088/1475-7516/2021/12/046.
Abstract (sommario):
Abstract Baryonic feedback effects consist of a major systematic for upcoming weak-lensing and galaxy-clustering surveys. In this paper, we present an emulator for the baryonic suppression of the matter power spectrum. The emulator is based on the baryonification model, containing seven free parameters that are connected to the gas profiles and stellar abundances in haloes. We show that with the baryonic emulator, we can not only recover the power spectra of hydro-dynamical simulations at sub-percent precision, but also establish a connection between the baryonic suppression of the power spectrum and the gas and stellar fractions in haloes. This connection allows us to predict the expected deviation from a dark-matter-only power spectrum using measured X-ray gas fractions of galaxy groups and clusters. With these measurements, we constrain the suppression to exceed the percent-level at k=0.1-0.4 h/Mpc and to reach a maximum of 20-28 percent at around k∼ 7 h/Mpc (68 percent confidence level). As a further step, we also perform a detailed parameter study and we present a minimum set of four baryonic parameters that are required to recover the scale and redshift dependence observed in hydro-dynamical simulations. The baryonic emulator can be found at https://github.com/sambit-giri/BCemu.
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da Silva, Bruno, An Braeken, Federico Domínguez e Abdellah Touhafi. "Exploiting Partial Reconfiguration through PCIe for a Microphone Array Network Emulator". International Journal of Reconfigurable Computing 2018 (2018): 1–16. http://dx.doi.org/10.1155/2018/3214679.
Abstract (sommario):
The current Microelectromechanical Systems (MEMS) technology enables the deployment of relatively low-cost wireless sensor networks composed of MEMS microphone arrays for accurate sound source localization. However, the evaluation and the selection of the most accurate and power-efficient network’s topology are not trivial when considering dynamic MEMS microphone arrays. Although software simulators are usually considered, they consist of high-computational intensive tasks, which require hours to days to be completed. In this paper, we present an FPGA-based platform to emulate a network of microphone arrays. Our platform provides a controlled simulated acoustic environment, able to evaluate the impact of different network configurations such as the number of microphones per array, the network’s topology, or the used detection method. Data fusion techniques, combining the data collected by each node, are used in this platform. The platform is designed to exploit the FPGA’s partial reconfiguration feature to increase the flexibility of the network emulator as well as to increase performance thanks to the use of the PCI-express high-bandwidth interface. On the one hand, the network emulator presents a higher flexibility by partially reconfiguring the nodes’ architecture in runtime. On the other hand, a set of strategies and heuristics to properly use partial reconfiguration allows the acceleration of the emulation by exploiting the execution parallelism. Several experiments are presented to demonstrate some of the capabilities of our platform and the benefits of using partial reconfiguration.
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Garg, Anjali. "Solar Power Analysis Under Varying Environmental Condition Using Solar Emulator". International Journal of Sustainable Energy and Environmental Research 10, n. 2 (28 dicembre 2021): 101–13. http://dx.doi.org/10.18488/journal.13.2021.102.101.113.
Abstract (sommario):
The current situation of fast depleting non-renewable resources and excessive damage done to mother earth due to severe mechanization and industrialization has resulted in alarming rate of pollutions. The one-word answer for it is that we should start harnessing renewable resources of energy. Tapping sun’s energy is a wonderful and apt answer to the current situation of energy requirement. World over this technology is worked upon to make use of sun’s energy easy to be converted into usable energy form i.e. electricity. The research work being carried on in varied fields however to mention one such aspect of solar panels is irradiance -receiving and capturing powers. Along with the irradiance, the area of a panel which is exposed to sun, the daytime and location are some of the factors affecting the amount of power generated using solar power as generating source. From research point of view, to analyze the effect of variation of these parameters, it is difficult to get the analysis data using solar panels and hence now a day’s emulator is preferred and used for research purposes. This paper focuses on the basics of emulator, its structure, functioning, effect of various parameter variations on the analysis of the generated power and other related benefits using emulator. The paper also presents the effect of partial shading on the maximum power generated and the efficiency hence obtained. The performance analysis is done on an Experimental set up fabricated in Research lab.