Journal articles: 'Thermionic converters – Computer simulation'

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Merkulov, A. I., A. Yu Lavrov, and D. S. Burkov. "Features computer simulation cluster charactiristics electromagnetic converters." VESTNIK of the Samara State Aerospace University, no. 2(44) (October 24, 2014): 98. http://dx.doi.org/10.18287/1998-6629-2014-0-2(44)-98-104.

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Martí, Antonio. "Analysis of the Thermodynamic Consistency of the Richardson–Duhmann Model for Thermionic Converters." Energies 13, no. 5 (March 1, 2020): 1087. http://dx.doi.org/10.3390/en13051087.

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In this work, we develop the general theory for analyzing the thermodynamic consistency of the Richardson–Duhmann model for vacuum thermionic energy converters. In addition to the electron fluxes from emitter to collector and vice versa, we calculate the energy and entropy fluxes associated to them. The calculation of the entropy fluxes is what allows us to conclude that the model is consistent by verifying that both at the emitter and at the collector the entropy generation rate is positive. In the process, we review the Richardson–Duhmann model in order to assure that the assumptions we make for calculating the energy and entropy fluxes are consistent. We also generalize the Richardson–Duhmann model in order to consider Fermi–Dirac statistics.

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Hrovat, D., and W. E. Tobler. "Bond graph modeling and computer simulation of automotive torque converters." Journal of the Franklin Institute 319, no. 1-2 (January 1985): 93–114. http://dx.doi.org/10.1016/0016-0032(85)90067-5.

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Yang, Yang, Wei Wei Cao, Peng Xu, Bing Li Zhu, Yong Lin Bai, Bo Wang, Jun Jun Qin, and Xiao Hong Bai. "Temperature-Dependent Analysis of Solid-State Photon-Enhanced Thermionic Emission Solar Energy Converter." Energies 13, no. 7 (March 27, 2020): 1554. http://dx.doi.org/10.3390/en13071554.

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Solid-state photon-enhanced thermionic emission (PETE) solar energy converters are newly proposed devices that can directly convert solar energy into electrical power at high temperatures. An analytical model based on a one-dimensional steady-state equation is developed to analyze the temperature-dependent performance of the solid-state PETE converter. The treatment used to derive the reverse saturation current density ( J 0 ) and open-circuit voltage ( V o c ) of the solid-state PETE converter is similar to that used in photovoltaic cells. Thus, their performances at elevated temperatures can be compared. Analysis results show that J 0 of the solid-state PETE converter with a GaAs absorption layer is approximately three orders of magnitude lower, and the decrease rate of open-circuit voltage ( − d V o c / d T ) is smaller than that of a practical GaAs photovoltaic cell. The improved performance of the solid-state PETE converter at high temperatures is attributed to the simultaneous use of diffusion and ballistic transport to harvest photo-generated electrons. The results presented in this paper demonstrate that, besides using wide bandgap materials and increasing doping density, harvesting solar energy via PETE effect can effectively improve the performance of solar cells at elevated temperatures.

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Elnashaie, S. S. E. H., and F. M. Alhabdan. "Mathematical modelling and computer simulation of industrial water–gas shift converters." Mathematical and Computer Modelling 12, no. 8 (1989): 1017–34. http://dx.doi.org/10.1016/0895-7177(89)90208-2.

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Dessaint, Louis-A., and Kamal Al-Haddad. "Modelling and Simulation of Electric Machines, Converters and Systems." Mathematics and Computers in Simulation 63, no. 3-5 (November 2003): 135. http://dx.doi.org/10.1016/s0378-4754(03)00170-8.

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Yao, Jia, Kewei Li, Kaisheng Zheng, and Alexander Abramovitz. "On the Equivalence of the Switched Inductor and the Tapped Inductor Converters and its Application to Small Signal Modelling." Energies 12, no. 24 (December 17, 2019): 4806. http://dx.doi.org/10.3390/en12244806.

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Switched inductor (SI) converters are popular in applications requiring a steeper conversion ratio. However, these converters operate a twin inductor switching cell, which complicates the small-signal modeling. This paper proposes an expeditious small-signal analysis method to model the SI converters. The offered modeling approach is hinged on the analogy existing between the SI converters and certain Tapped Inductor (TI) converters. It is suggested here that by virtue of the analogy of the SI converters and TI converters the small-signal model of the SI converter is identical to that of its ideal TI counterpart. Hence, the recently developed Tapped Inductor Switcher (TIS) methodology can be applied to the modeling of the SI converters as well. As an example, the small-signal model of the Switched Inductor Buck converter is obtained. Theoretical analysis was confirmed by simulation and experimental results. In addition, several other SI converters and their TI counterparts are identified.

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Naz*, Farha. "Closed loop Buck & Boost Converter Mathematical Modeling, Analysis and Simulation using MATLAB." International Journal of Engineering and Advanced Technology 10, no. 4 (April 30, 2021): 263–71. http://dx.doi.org/10.35940/ijeat.d2525.0410421.

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This article presents the converter circuit analysis, mathematical modeling followed by deriving its average state space equations. The model so obtained is simulated in MATLAB in open loop and closed loop configuration and changes in the output are observed. Specifically, Buck & Boost converters with & without its controller at steady state and study of their transient responses to the changing inputs with a controller design and its implementation on SIMULINK model is presented here. The method used to control the output of the converter is Proportional and Integral error correction that is a PI controller which is used to reduce errors and stabilize the variable input fed to the Buck or Boost converters. The tool used to design the controller parameters is PID Tuner application in in MATLAB. The analyses plots derived using the tool lets us examine the controller performance in time and frequency domain. The advantage of the tool used is, it allows user to interactively refine the performance of the controller to adjust loop bandwidth and phase margin or to favor a set-point tracking or disturbance rejection. The designed converters are analyzed in current mode control and voltage mode control to switch on/off. The long term goal is to have a sophisticated controller design for buck & boost converters for the application where variable input is fed to them, so as to allow its simulation to fully understand how the converters behave when controller is implemented. The model tested here are of the similar nature that are being used in standalone solar or wind energy generation & distribution systems. The variable nature of the input tested here with Buck & Boost converters reflects the variable nature of the output of the renewable energy sources and that broaden the scope of these converters to be implanted with such standalone energy systems

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Pienkos, Tomasz, Maciej Czarnacki, Tomasz Durakiewicz, and Stanislaw Halas. "Work function of 75W25Re alloy determined with thermionic emission method aided by computer simulation." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 29, no. 5 (September 2011): 051601. http://dx.doi.org/10.1116/1.3610984.

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Estrada, Leonel, Nimrod Vázquez, Joaquín Vaquero, Ángel de Castro, and Jaime Arau. "Real-Time Hardware in the Loop Simulation Methodology for Power Converters Using LabVIEW FPGA." Energies 13, no. 2 (January 13, 2020): 373. http://dx.doi.org/10.3390/en13020373.

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Nowadays, the use of the hardware in the loop (HIL) simulation has gained popularity among researchers all over the world. One of its main applications is the simulation of power electronics converters. However, the equipment designed for this purpose is difficult to acquire for some universities or research centers, so ad-hoc solutions for the implementation of HIL simulation in low-cost hardware for power electronics converters is a novel research topic. However, the information regarding implementation is written at a high technical level and in a specific language that is not easy for non-expert users to understand. In this paper, a systematic methodology using LabVIEW software (LabVIEW 2018) for HIL simulation is shown. A fast and easy implementation of power converter topologies is obtained by means of the differential equations that define each state of the power converter. Five simple steps are considered: designing the converter, modeling the converter, solving the model using a numerical method, programming an off-line simulation of the model using fixed-point representation, and implementing the solution of the model in a Field-Programmable Gate Array (FPGA). This methodology is intended for people with no experience in the use of languages as Very High-Speed Integrated Circuit Hardware Description Language (VHDL) for Real-Time Simulation (RTS) and HIL simulation. In order to prove the methodology’s effectiveness and easiness, two converters were simulated—a buck converter and a three-phase Voltage Source Inverter (VSI)—and compared with the simulation of commercial software (PSIM® v9.0) and a real power converter.

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Li, Yahui, Pu Deng, Jing Zhang, Donghang Liu, and Zhenghang Hao. "A Study of Interpolation Compensation Based Large Step Simulation of PWM Converters." Energies 13, no. 12 (June 13, 2020): 3069. http://dx.doi.org/10.3390/en13123069.

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Real-time online simulation based on a real-time workshop (RTW) plays a vital role in the study and application of power electronics. However, restricted by the performance of equipment and hardware, the simulators so far available in the market mainly support simulation steps over 50 μs, while large step simulation may result in the action delay of pulse-width modulating (PWM), numerical oscillation and high-level non-characteristic harmonic distortion. In view of these problems, this paper puts forward a modeling method based on integral prediction and interpolation compensation. First of all, prediction is performed one step in advance by the implicit trapezoidal method to find out the accurate time when the triangle carrier wave intersects with the modulation wave. At the same time, a mathematic model is built for the insulated gate bipolar transistor (IGBT) to output equivalent voltage waveform according to the principle of area equivalent. Next, in MATLAB/Simulink, offline simulation is performed with the three-phase AC-DC-AC converter as the subject. By comparing the control accuracy, the content of harmonic wave and the simulation time, the simulation effects of the 50 μs fixed-step interpolation prediction model are the same as that for a 5 μs fixed-step standard model. Finally, the effectiveness and high efficiency of this algorithm are verified on a real-time simulator, marking the application of offline models on real-time simulators.

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Beatty, Scott, Francesco Ferri, Bryce Bocking, Jens Kofoed, and Bradley Buckham. "Power Take-Off Simulation for Scale Model Testing of Wave Energy Converters." Energies 10, no. 7 (July 11, 2017): 973. http://dx.doi.org/10.3390/en10070973.

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Bhaskar, Mahajan Sagar, Sanjeevikumar Padmanaban, and Jens Bo Holm-Nielsen. "Double Stage Double Output DC–DC Converters for High Voltage Loads in Fuel Cell Vehicles." Energies 12, no. 19 (September 26, 2019): 3681. http://dx.doi.org/10.3390/en12193681.

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This article aims to enhance the output voltage magnitude of fuel cells (FCs), since the actual generation is low. The traditional technique is too complicated and has a cascaded or parallel connection solution to achieve high voltage for multiple loads in vehicles. In this case, electronic power converters are a viable solution with compact size and cost. Hence, double or multiple output DC–DC converters with high voltage step up are required to feed multiple high voltage loads at the same time. In this article, novel double stage double output (DSDO) DC–DC converters are formulated to feed multiple high voltage loads of FC vehicular system. Four DSDO DC–DC converters called DSDO L–L, DSDO L-2L, DSDO L-2LC, and DSDO L-2LC are developed in this research work and all the converters are derived based on the arrangement of different reactive networks. The primary power circuitry, conceptual operation, and output voltage gain derivation are given in detail with valid proof. The proposed converters are compared with possible parallel combinations of conventional converters and recently available configuration. Comprehensive numerical simulation and experimental prototype results show that our theoretical predictions are valid and that the configuration is applicable for real time application in FC technologies for ‘more-electric vehicles’.

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Corti, Fabio, Antonino Laudani, Gabriele Maria Lozito, and Alberto Reatti. "Computationally Efficient Modeling of DC-DC Converters for PV Applications." Energies 13, no. 19 (September 30, 2020): 5100. http://dx.doi.org/10.3390/en13195100.

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In this work, a computationally efficient approach for the simulation of a DC-DC converter connected to a photovoltaic device is proposed. The methodology is based on a combination of a highly efficient formulation of the one-diode model for photovoltaic (PV) devices and a state-space formulation of the converter as well as an accurate steady-state detection methodology. The approach was experimentally validated to assess its accuracy. The model is accurate both in its dynamic response (tested in full linearity and with a simulated PV device as the input) and in its steady-state response (tested with an outdoor experimental measurement setup). The model detects automatically the reaching of a steady state, thus resulting in lowered computational costs. The approach is presented as a mathematical model that can be efficiently included in a large simulation system or statistical analysis.

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Zhu, Binxin, Qingdian Zeng, Mahinda Vilathgamuwa, Yang Li, and Yao Chen. "A Generic Control-Oriented Model Order Reduction Approach for High Step-Up DC/DC Converters Based on Voltage Multiplier." Energies 12, no. 10 (May 23, 2019): 1971. http://dx.doi.org/10.3390/en12101971.

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The modeling and control system design of high step-up DC/DC converters based on voltage multipliers (VMs) are difficult, due to the various circuit topologies and the presence of large number of capacitors in VMs. This paper proposes a generic approach to reduce the model order of such converters by replacing the VM capacitors with voltage sources controlled by the output voltage of the converter. Theoretical analysis and simulation results show that the derived models can accurately represent the low frequency response of the converter which is valuable for obtaining a small-signal AC model for control system design. The detailed modeling and controller design process are demonstrated for the converter, and the obtained simulation results are verified experimentally on a 400 W prototype.

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Stala, Robert, Zbigniew Waradzyn, and Szymon Folmer. "DC-DC High-Voltage-Gain Converters with Low Count of Switches and Common Ground." Energies 13, no. 21 (October 29, 2020): 5657. http://dx.doi.org/10.3390/en13215657.

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This paper presents a new concept and research results of DC-DC high-voltage-gain, high-frequency step-up resonant converters. The proposed topologies are optimized towards minimizing the number of switches and improvements in efficiency. Another relevant advantage of such type of converters is that they have a common input and output negative point. The proposed converters are based on the resonant switched-capacitor voltage multiplier circuit, and that is why they are compared with a classic converter from this family. The included results show the operating principle, possible switching methods with the consideration of their impact on the voltage gain level, as well as the voltage and current ripples. The operating concepts and analytical calculations are confirmed by simulation and experimental results.

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Karthikeyan, M., R. Elavarasu, P. Ramesh, C. Bharatiraja, P. Sanjeevikumar, Lucian Mihet-Popa, and Massimo Mitolo. "A Hybridization of Cuk and Boost Converter Using Single Switch with Higher Voltage Gain Compatibility." Energies 13, no. 9 (May 6, 2020): 2312. http://dx.doi.org/10.3390/en13092312.

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In the current era, the desire for high boost DC-to-DC converter development has increased. Notably, there has been voltage gain improvement without adding extra power switches, and a large number of passive components have advanced. Magnetically coupled isolated converters are suggested for the higher voltage gain. These converters use large size inductors, and thus the non-isolated traditional boost, Cuk and Sepic converters are modified to increase their gain by adding an extra switch, inductors and capacitors. These converters increase circuit complexity and become bulky. In this paper, we present a hybrid high voltage gain non-isolated single switch converter for photovoltaic applications. The proposed converter connects the standard conventional Cuk and boost converter in parallel for providing continuous current mode operation with the help of a single power switch, which gives less voltage stress on controlled switch and diodes. The proposed hybrid topology uses a single switch with a lower component-count and provides a higher voltage gain than non-isolated traditional converters. The converter circuit mode of operation, operating performance, mathematical derivations and steady-state exploration and circuit parameters design procedures are deliberated in detail. The proposed hybrid converter circuit components, voltage gain and performance, were compared with other topologies in the literature. The MATLAB/Simulink simulation study and microcontroller-based experimental laboratory prototype of 150 W were implemented. The simulation study and experimentation results were confirmed to be a satisfactory agreement with the theoretical analysis. This topology produced non-inverting output in continuous input current mode using a single switch with high voltage gain (≈5.116 gain) with a maximum efficiency of 92.2% under full load.

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Chen, Xunjun, and Zhigang Liu. "Impedance Modeling and Stability Analysis of the Converters in a Double-Fed Induction Generator (DFIG)-Based System." Energies 12, no. 13 (June 28, 2019): 2500. http://dx.doi.org/10.3390/en12132500.

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Harmonic stability of double-fed induction generators (DFIGs) now has become a significant topic because of its harmful impact on power quality issues of the system. Since the double pulse width modulation (PWM) converter is one of the main harmonic sources in DFIGs, it may cause harmonic instability with increasing harmonic contents. Thus, the modeling and stability analyses of PWM converters in DFIGs are essential steps to assess the harmonic stability of DFIGs. Aiming at dual PWM converters, which include the grid side converter (GSC) and the rotor side converter (RSC), this paper divides converters into two parts: circuit modules and control modules. Closed-loop input impedance models of each module are then derived by means of transfer functions. Hence, the stability of the system can be readily predicted through Nyquist diagrams. The contributions of parameters to the system’s harmonic stability are also identified. Finally, time-domain simulations are conducted in a real-time digital simulation (RTDS) system. Simulation results confirm that the established impedance model can effectively reveal the stability of the DFIG-based system and can give critical conditions for the occurrence of harmonic instability.

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Shebani, Muamer M., Tariq Iqbal, and John E. Quaicoe. "Modified Droop Method Based on Master Current Control for Parallel-Connected DC-DC Boost Converters." Journal of Electrical and Computer Engineering 2018 (July 17, 2018): 1–14. http://dx.doi.org/10.1155/2018/9819787.

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Load current sharing between parallel-connected DC-DC boost converters is very important for system reliability. This paper proposes a modified droop method based on master current control for parallel-connected DC-DC boost converters. The modified droop method uses an algorithm for parallel-connected DC-DC boost converters to adaptively adjust the reference voltage for each converter according to the load regulation characteristics of the droop method. Unlike the conventional droop method, the current feedback signal (master current) for one of the parallel-connected converters is used in the inner loop controller for all converters to avoid any differences in the time delay of the control loops for the parallel-connected converters. The algorithm ensures that the load current sharing is identical to the load regulation characteristics of the droop method. The proposed algorithm is tested with a mismatch in the parameters of the parallel converters. The effectiveness of the proposed algorithm is verified using Matlab/Simulink simulation.

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Du, Wenzeng, Genke Yang, Changchun Pan, Peifeng Xi, and Yue Chen. "A Sliding-Mode-Based Duty Ratio Controller for Multiple Parallelly-Connected DC–DC Converters with Constant Power Loads on MVDC Shipboard Power Systems." Energies 13, no. 15 (July 30, 2020): 3888. http://dx.doi.org/10.3390/en13153888.

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The development of powered electronic technology has made many aware of the design and control of ship power systems (SPSs), and has made medium voltage DC (MVDC) architecture the main research direction in the future. The negative impedance characteristic of constant power load (CPL) generated by the coupling of powered electronic converters will seriously affect the stability of the systems if these converters are not properly controlled. The conventional linear control method can only guarantee the small-signal stability of the system near its equilibrium point. When the operating point changes in a large range, linear control methods will be ineffective. More importantly, research for the large-signal stability of the multi-converter system with CPLs is still rarely involved. In this paper, a sliding-mode-based duty ratio controller (SMDC) is proposed for voltage regulation and current sharing of the multiple parallelly-connected DC–DC converters system loaded by CPLs. By controlling the output voltage of each converter with SMDC, large-signal stability of the coupled bus voltage is ensured. Meanwhile, proportional current sharing between the parallel converters is achieved by droop control integrated in the reference value of converter voltage. Simulation studies were conducted in MATLAB/Simulink, where two typical operating conditions, including the variation of load power and bus voltage, were designed to verify the effectiveness of the proposed method. Moreover, a traditional PID controller was used as a comparison to reflect the superiority of the former. Simulation results showed that the proposed method is able to guarantee large-signal stability of the system in the presence of large-scale variations in load power and bus voltage. The output current of the parallel converters can also be distributed in desired proportions according to the droop coefficient.

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Liang, Haifeng, Yue Dong, Yuxi Huang, Can Zheng, and Peng Li. "Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration." Energies 11, no. 9 (August 24, 2018): 2223. http://dx.doi.org/10.3390/en11092223.

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The stable operation of a microgrid is crucial to the integration of renewable energy sources. However, with the expansion of scale in electronic devices applied in the microgrid, the interaction between voltage source converters poses a great threat to system stability. In this paper, the model of a three-source microgrid with a multi master–slave control method in islanded mode is built first of all. Two sources out of three use droop control as the main control source, and another is a subordinate one with constant power control which is also known as real and reactive power (PQ) control. Then, the small signal decoupling control model and its stability discriminant equation are established combined with “virtual impedance”. To delve deeper into the interaction between converters, mutual influence of paralleled converters of two main control micro sources and their effect on system stability is explored from the perspective of control parameters. Finally, simulation and analysis are launched and the study serves as a reference for parameter setting of converters in a microgrid.

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Nelms, R. M., Louis F. Lollar, and L. L. Grigsby. "State variable analysis of dc-dc converters." SIMULATION 50, no. 2 (February 1988): 61–65. http://dx.doi.org/10.1177/003754978805000202.

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Farrokhseresht, Nakisa, Arjen A. van der Meer, José Rueda Torres, and Mart A. M. M. van der Meijden. "MOSAIK and FMI-Based Co-Simulation Applied to Transient Stability Analysis of Grid-Forming Converter Modulated Wind Power Plants." Applied Sciences 11, no. 5 (March 9, 2021): 2410. http://dx.doi.org/10.3390/app11052410.

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The grid integration of renewable energy sources interfaced through power electronic converters is undergoing a significant acceleration to meet environmental and political targets. The rapid deployment of converters brings new challenges in ensuring robustness, transient stability, among others. In order to enhance transient stability, transmission system operators established network grid code requirements for converter-based generators to support the primary control task during faults. A critical factor in terms of implementing grid codes is the control strategy of the grid-side converters. Grid-forming converters are a promising solution which could perform properly in a weak-grid condition as well as in an islanded operation. In order to ensure grid code compliance, a wide range of transient stability studies is required. Time-domain simulations are common practice for that purpose. However, performing traditional monolithic time domain simulations (single solver, single domain) on a converter-dominated power system is a very complex and computationally intensive task. In this paper, a co-simulation approach using the mosaik framework is applied on a power system with grid-forming converters. A validation workflow is proposed to verify the co-simulation framework. The results of comprehensive simulation studies show a proof of concept for the applicability of this co-simulation approach to evaluate the transient stability of a dominant grid-forming converter-based power system.

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Najafi, Parviz, Abbas Houshmand Viki, Mahdi Shahparasti, S. Sajjad Seyedalipour, and Edris Pouresmaeil. "A Novel Space Vector Modulation Scheme for a 10-Switch Converter." Energies 13, no. 7 (April 10, 2020): 1855. http://dx.doi.org/10.3390/en13071855.

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Three-level converters have drawn extensive attention due to their ability to deliver high-quality power. High semiconductor count is the main drawback of three-level converters. As a solution to this, a 10-switch converter is presented, that has advantages over both two- and three-level converters, simultaneously, plus it is applicable to a variety of power ranges. However, the switching pattern of 10-switch converter is not as simple as standard three-level converter due to lack of medium vectors. This paper presents a novel space vector modulation (SVM) for a 10-switch converter to reduce total harmonic distortion (THD) and common mode voltage (CMV) of this converter in comparison to prior carrier-based modulation methods. A simplified, low-cost modulation algorithm for the converter is proposed. The designed switching sequence has aimed at a low output THD and enhancement of DC bus voltage utilization. The performance of the proposed SVM is then compared to upgraded sinusoidal PWM. AC power quality and CMV of a 10-switch converter based on two modulation methods are investigated via simulation models. It was validated via simulation and experimental models that the proposed SVM utilized DC bus voltage more efficiently, generated remarkably less THD compared to other methods, and had a lower peak and rms CMV.

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Lin, Yuan-Chih, Ding-Tang Chen, and Ching-Jan Chen. "Flux-Balance Control for LLC Resonant Converters with Center-Tapped Transformers." Energies 12, no. 17 (August 21, 2019): 3211. http://dx.doi.org/10.3390/en12173211.

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LLC resonant converters with center-tapped transformers are widely used. However, these converters suffer from a flux walking issue, which causes a larger output ripple and possible transformer saturation. In this paper, a flux-balance control strategy is proposed for resolving the flux walking issue. First, the DC magnetizing current generated due to the mismatched secondary-side leakage inductances, and its effects on the voltage gain are analyzed. From the analysis, the flux-balance control strategy, which is based on the original output-voltage control loop, is proposed. Since the DC magnetizing current is not easily measured, a current sensing strategy with a current estimator is proposed, which only requires one current sensor and is easy to estimate the DC magnetizing current. Finally, a simulation scheme and a hardware prototype with rated output power 200 W, input voltage 380 V, and output voltage 20 V is constructed for verification. The simulation and experimental results show that the proposed control strategy effectively reduces the DC magnetizing current and output voltage ripple at mismatched condition.

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Heras Cervantes, Mario, Adriana del Carmen Tellez Anguiano, Juan Anzurez Marin, Elisa Espinosa Juarez, Maria del Carmen Garcia Ramirez, and Javier Correa Gomez. "Real-Time Simulation of a Luenberger Observer Applied to DC-DC Converters." IEEE Latin America Transactions 16, no. 3 (March 2018): 981–86. http://dx.doi.org/10.1109/tla.2018.8358682.

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Loncarski, Jelena, Vito Giuseppe Monopoli, Giuseppe Leonardo Cascella, and Francesco Cupertino. "SiC-MOSFET and Si-IGBT-Based dc-dc Interleaved Converters for EV Chargers: Approach for Efficiency Comparison with Minimum Switching Losses Based on Complete Parasitic Modeling." Energies 13, no. 17 (September 3, 2020): 4585. http://dx.doi.org/10.3390/en13174585.

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Widespread dissemination of electric mobility is highly dependent on the power converters, storage systems and renewable energy sources. The efficiency and reliability, combined with the emerging and innovative technologies, are crucial when speaking of power converters. In this paper the interleaved dc–dc topology has been considered for EV charging, due to its improved reliability. The efficiency comparison of the SiC-MOSFET and Si-IGBT-based converters has been done on wide range of switching frequency and output inductances. The interleaved converters were considered with the optimal switching parameters resulting from the analysis done on a detailed parasitic circuit model, ensuring minimum losses and maintaining the safe operating area. The analysis included the comparison of different inductors, and for the selected ones the complete system efficiency and cost were conducted. The results indicate the benefits when SiC-MOSFETs are applied to the interleaved dc–dc topology for wide ranges of output inductances and switching frequencies, and most importantly, they offer lower total volume but also total cost. The realistic and dynamic models of power devices obtained from the manufacturer’s experimental tests have been considered in both LTspice and PLECS simulation tools.

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Wei, Yingdong, Dewu Shu, Xiaorong Xie, Venkata Dinavahi, and Zheng Yan. "Real-Time Simulation of Hybrid Modular Multilevel Converters Using Shifted Phasor Models." IEEE Access 7 (2019): 2376–86. http://dx.doi.org/10.1109/access.2018.2884506.

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Fang, Jingyang. "Unified Graph Theory-Based Modeling and Control Methodology of Lattice Converters." Electronics 10, no. 17 (September 3, 2021): 2146. http://dx.doi.org/10.3390/electronics10172146.

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Lattice converters combine the merits of both cascaded-bridge converters and multi-paralleled converters, leading to infinitely large current and voltage capabilities with modularity and scalability as well as small passive components. However, lattice converters suffer from complexity, which poses a serious threat to their widespread adoption. By use of graph theory, this article proposes a unified modeling and control methodology for various lattice converters, resulting in the satisfaction of their key control objectives, including selected inputs/outputs, desired voltages, current sharing, dynamic voltage balancing, and performance optimization. In addition, this article proposes a plurality of novel lattice converter topologies, which complement state-of-the-art options. Simulation and experimental results verify the effectiveness and superiority of the proposed methodology and lattice converters.

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Szymanski, Jerzy Ryszard, Marta Zurek-Mortka, Daniel Wojciechowski, and Nikolai Poliakov. "Unidirectional DC/DC Converter with Voltage Inverter for Fast Charging of Electric Vehicle Batteries." Energies 13, no. 18 (September 14, 2020): 4791. http://dx.doi.org/10.3390/en13184791.

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The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.

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Zhou, Shijia, Fei Rong, Zhangtao Yin, Shoudao Huang, and Yuebin Zhou. "HVDC Transmission Technology of Wind Power System with Multi-Phase PMSG." Energies 11, no. 12 (November 26, 2018): 3294. http://dx.doi.org/10.3390/en11123294.

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The high voltage DC (HVDC) transmission technology of wind power system, with multi-phase permanent magnetic synchronous generator (PMSG) is proposed in this paper. Each set of three-phase winding of the multi-phase PMSG was connected to a diode rectifier. The output of the diode rectifier was connected by several parallel isolated DC–DC converters. Each DC–DC converter was connected to a sub-module (SM). All SMs and two inductors were connected in a series. The proposed wind power system has several advantages including, transformerless operation, low cost, low voltage stress, and high fault tolerance. The maximum power point tracking (MPPT) and energy balance of the DC–DC converters were achieved by controlling the duty cycles of the DC–DC converters. The HVDC transmission was achieved by the nearest level control (NLC) with voltage sorting. The simulation model with 18-phase PMSG was established. Experimental results were also studied based on RT-Lab.

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Dunaev, Mikhail, and Sarfaroz Dovudov. "Comparing the Energy Performance of Pulsed DC Converters According to the Results of Computer Simulation." Electrotechnical Systems and Complexes, no. 1(50) (March 26, 2021): 35–41. http://dx.doi.org/10.18503/2311-8318-2021-1(50)-35-41.

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Verdugo, Cristian, Samir Kouro, Christian A. Rojas, Marcelo A. Perez, Thierry Meynard, and Mariusz Malinowski. "Five-Level T-type Cascade Converter for Rooftop Grid-Connected Photovoltaic Systems." Energies 12, no. 9 (May 8, 2019): 1743. http://dx.doi.org/10.3390/en12091743.

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Multilevel converters are widely considered to be the most suitable configurations for renewable energy sources. Their high-power quality, efficiency and performance make them interesting for PV applications. In low-power applications such as rooftop grid-connected PV systems, power converters with high efficiency and reliability are required. For this reason, multilevel converters based on parallel and cascaded configurations have been proposed and commercialized in the industry. Motivated by the features of multilevel converters based on cascaded configurations, this work presents the modulation and control of a rooftop single-phase grid-connected photovoltaic multilevel system. The configuration has a symmetrical cascade connection of two three-level T-type neutral point clamped power legs, which creates a five-level converter with two independent string connections. The proposed topology merges the benefits of multi-string PV and symmetrical cascade multilevel inverters. The switching operation principle, modulation technique and control scheme under an unbalanced power operation among the cell are addressed. Simulation and experimental validation results in a reduced-scale power single-phase converter prototype under variable conditions at different set points for both PV strings are presented. Finally, a comparative numerical analysis between other T-type configurations to highlight the advantages of the studied configuration is included.

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IOINOVICI, ADRIAN, and SORIN COSTINER. "COMPUTER-AIDED ANALYSIS OF CYCLICALLY SWITCHING CIRCUITS WITH IMPLICIT CONTROLLED TRANSITION TIMES." Journal of Circuits, Systems and Computers 01, no. 04 (December 1991): 373–99. http://dx.doi.org/10.1142/s0218126691000136.

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The power electronics circuits can be seen as a subset of periodically switched networks. Their distinctive feature is the variable duration of the switching stages, dependent on implicit, threshold conditions. The paper presents a new computer-oriented approach for transient and steady-state analysis of this class of electronic circuits. The switching elements are extracted in a linear time-variable two-port, which is defined by its nodal equations. A set of modified nodal equations is obtained for describing the overall transient of the circuit. No small-signal approximations are required. The analytical expressions of the network waveforms are found accurately for each switching stage. The transient computation is based on the cyclical use of these expressions together with the threshold conditions. The general method is then applied to simulation of current-mode quasi-resonant converters. Transients due to large-signal changes in the line voltage and load are studied. The influence of the load value on transient peaks is pointed out. The voltage conversion ratio versus switching frequency is studied for both the half- and full-wave mode operation. A computer program for time-domain simulation of power quasi-resonant converters is developed based on this approach.

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Frivaldsky, Michal, Jan Morgos, Michal Prazenica, and Kristian Takacs. "System Level Simulation of Microgrid Power Electronic Systems." Electronics 10, no. 6 (March 10, 2021): 644. http://dx.doi.org/10.3390/electronics10060644.

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In this paper, we describe a procedure for designing an accurate simulation model using a price-wised linear approach referred to as the power semiconductor converters of a DC microgrid concept. Initially, the selection of topologies of individual power stage blocs are identified. Due to the requirements for verifying the accuracy of the simulation model, physical samples of power converters are realized with a power ratio of 1:10. The focus was on optimization of operational parameters such as real-time behavior (variable waveforms within a time domain), efficiency, and the voltage/current ripples. The approach was compared to real-time operation and efficiency performance was evaluated showing the accuracy and suitability of the presented approach. The results show the potential for developing complex smart grid simulation models, with a high level of accuracy, and thus the possibility to investigate various operational scenarios and the impact of power converter characteristics on the performance of a smart gird. Two possible operational scenarios of the proposed smart grid concept are evaluated and demonstrate that an accurate hardware-in-the-loop (HIL) system can be designed.

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Melicio, R., V. M. F. Mendes, and J. P. S. Catalao. "Modeling and Simulation of Wind Energy Systems with Matrix and Multilevel Power Converters." IEEE Latin America Transactions 7, no. 1 (March 2009): 78–84. http://dx.doi.org/10.1109/tla.2009.5173468.

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Saad, Muhammad, Husan Ali, Huamei Liu, Shahbaz Khan, Haider Zaman, Bakht Khan, Du Kai, and Ju Yongfeng. "A dq-Domain Impedance Measurement Methodology for Three-Phase Converters in Distributed Energy Systems." Energies 11, no. 10 (October 12, 2018): 2732. http://dx.doi.org/10.3390/en11102732.

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A distributed energy system (DES) using controlled power electronics converters delivers power to loads, via conventional, as well as a number of renewable, energy sources. However, stability concerns retard the integration of power electronics converters into an existing DES. Therefore, due to the high penetration of power converters, the overall network analysis of DES is becoming increasingly difficult. Impedance-based DES modeling emerged as an effective technique as it reduces the system into source and load subsystems and offers easier analysis of the dynamic interactions between them. These models can be obtained using either analytical calculations, simulations, or experimental measurements. In this work, firstly, a line-to-line current injection technique is used for the measurement of alternating current (AC) impedances. Since it requires repeated injections, a d q -domain impedance measurement methodology based upon a set of independent perturbations and measurements is proposed. The perturbation is injected via a sweep signal which is preprocessed by the digital signal processor (DSP) prior to injection. The d q reference frame is synchronized with the three-phase AC system using a low-bandwidth phase-locked loop (PLL). The close matching of impedance parameters measured in simulation using the proposed approach with those obtained using analytical expressions and the line-to-line current injection technique verifies the effectiveness of the approach. Furthermore, the method was also implemented experimentally, and the close matching of the results with the analytical and simulation results validates the overall modeling and measurement procedure.

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Wei, Chen, Xibo Yuan, Juan Zhou, Kangan Wang, Yonglei Zhang, and Xiaojie Wu. "Voltage Jump Suppression and Capacitor Voltage Fluctuation Analysis for a Four-Level Hybrid Flying Capacitor T-Type Converter." Energies 12, no. 4 (February 21, 2019): 698. http://dx.doi.org/10.3390/en12040698.

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In low and medium voltage power conversion systems, multilevel converters are becoming more and more attractive due to improved power density. However, the complexity of topology and control is a big challenge for the application of multilevel converters. In this paper, a four-level (4L) hybrid flying capacitor (FC) T-type converter has been researched in detail. The topological advantage of the converter is displayed in comparison to existing four-level converters. According to the feature of the topology, the operating status has been analyzed and the reason for the voltage jump is researched in detail during the dead-time period. A strategy to reduce voltage jump by adjusting the switching states has be presented. The FC voltages can be balanced by selecting the appropriate switching states. The relationships between the fluctuations of FC voltages and the modulation index and power factor (PF) have been analyzed by simulation results. The performance of the 4L converter has been investigated in MATLAB/Simulink as well as on a down-scaled laboratory prototype.

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Aldhaheri, Ahmed, and Amir Etemadi. "Adaptive Stabilization and Dynamic Performance Preservation of Cascaded DC-DC Systems by Incorporating Low Pass Filters." Energies 11, no. 2 (February 15, 2018): 440. http://dx.doi.org/10.3390/en11020440.

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This paper proposes a method to stabilize and enhance the dynamic performance of a cascaded DC-DC system by adaptively reshaping the source output impedance. The method aims to reduce the ratio of the source output impedance to the load input impedance, referred to as the minor loop gain, to eliminate the interaction between the load and the source systems. This interaction can deteriorate the dynamic performance or might lead to instability. Thus, the bus current is used to improve the dynamic performance by reducing the magnitude of the source’s output impedance adaptively according to the loading condition such that the dynamic performance is consistently improved. Utilizing the bus current facilitates the compatibility between the proposed controller and most widely used DC-DC converters controlled in voltage mode, including non-minimum phase converters. In addition to the flexibility the bus current provides to embed the proposed solution with conventional control schemes. Experimental results have validated the effectiveness of the proposed controller along with time-based simulation and theoretical analysis, for minimum and non-minimum phase converters.

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Garriga-Castillo, Juan A., Hugo Valderrama-Blavi, José A. Barrado-Rodrigo, and Àngel Cid-Pastor. "Analysis of Sliding-Mode Controlled Impedance Matching Circuits for Inductive Harvesting Devices." Energies 12, no. 20 (October 12, 2019): 3858. http://dx.doi.org/10.3390/en12203858.

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A sea-wave energy harvesting, articulated device is presented in this work. This hand-made, wooden device is made combining the coil windings of an array of three single transducers. Taking advantage of the sea waves sway, a linear oscillating motion is produced in each transducer generating an electric pulse. Magnetic fundamentals are used to deduce the electrical model of a single transducer, a solenoid-magnet device, and after the model of the whole harvesting array. The energy obtained is stored in a battery and is used to supply a stand-alone system pay-load, for instance a telecom relay or weather station. To maximize the harvested energy, an impedance matching circuit between the generator array and the system battery is required. Two dc-to-dc converters, a buck-boost hybrid cell and a Sepic converter are proposed as impedance adaptors. To achieve this purpose, sliding mode control laws are introduced to impose a loss free resistor behavior to the converters. Although some converters operating at discontinuous conduction mode, like the buck-boost converter, can exhibit also this loss free resistor behavior, they usually require a small input voltage variation range. By means of sliding mode control the loss free resistor behavior can be assured for any range of input voltage variation. After the theoretical analysis, several simulation and experimental results to compare both converters performance are given.

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Marchesoni, Mario, Massimiliano Passalacqua, and Luis Vaccaro. "A Refined Loss Evaluation of a Three-Switch Double Input DC-DC Converter for Hybrid Vehicle Applications." Energies 13, no. 1 (January 1, 2020): 204. http://dx.doi.org/10.3390/en13010204.

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In this paper, an accurate efficiency evaluation of an innovative three-switch double input DC–DC converter for hybrid vehicle applications was carried out. The converter was used to interface two storages, (e.g., supercapacitor and battery) to the DC link. A refined model was created in MATLAB/Simulink Plecs environment and it was used to compare the traditional four-switch converter (i.e., two DC–DC converters in parallel connection) with the innovative three-switch converter. Loss and efficiency contour maps were obtained for both converters and a comparison between them was performed. A prototype of the three-switch converter was realized and used to validate the simulation thermal model by comparing both efficiency and current waveforms obtained with simulations and experimental tests.

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Wang, Wei, M. N. S. Swamy, M. O. Ahmad, and Yuke Wang. "A Parallel Residue-to-binary Converter for the Moduli Set {2m−1,220m+1,221m+1,…,22km+1}." VLSI Design 14, no. 2 (January 1, 2002): 183–91. http://dx.doi.org/10.1080/10655140290010097.

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In this paper, a high-speed parallel residue-to-binary converter is proposed for a recently introduced moduli set Sk={2m−1,220m+1,221m+1,…,22km+1} for a general value of k. The proposed converter uses simple cyclic shift and concatenation operations and does not require any multiplier. Individual converters for the cases of k=0 and k=1 are derived from the general architecture and compared with those existing in the literature. The converter for S0 is twice as fast requiring only one-half of the hardware, while that of S1 is three times as fast, but requiring only 60% of the hardware, as compared to the corresponding ones existing in the literature. Furthermore, the proposed converters are implemented using 0.5-micron CMOS VLSI technology. Based on S0 , the layouts for 8-bit, 16-bit, 32-bit and 64-bit converters are generated, and the corresponding simulation results obtained.

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Avila, Deivis, Graciliano Nicolás Marichal, Ramón Quiza, and Felipe San Luis. "Prediction of Wave Energy Transformation Capability in Isolated Islands by Using the Monte Carlo Method." Journal of Marine Science and Engineering 9, no. 9 (September 7, 2021): 980. http://dx.doi.org/10.3390/jmse9090980.

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In this work, a mathematical computer simulation model is used to predict the possible energy generated from different Waves Energy Converters (WECs) in the Canary Islands. The Monte Carlo Method is the computer simulation model proposed to predict the generated energy. The Waves Energy Converter systems analyzed in the study were, the Aqua Buoy, Wave Dragon and Pelamis converters. The models were implemented and validated, with the dataset of Gran Canaria deep water buoy. This buoy belongs to a network of buoys belonging to Spain’s State Ports and they cover a dataset period of 22 years. The research has concluded that it is possible to affirm that the achieved model is a strong tool to compute the possible energy of any WECs, when the power matrix is known. The model based on the Monte Carlo simulation can be used in isolated islands of the Atlantic Ocean and can be extrapolated to other regions with the same characteristics.

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Abdelrahem, Mohamed, José Rodríguez, and Ralph Kennel. "Improved Direct Model Predictive Control for Grid-Connected Power Converters." Energies 13, no. 10 (May 20, 2020): 2597. http://dx.doi.org/10.3390/en13102597.

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This paper proposes a computationally efficient and robust direct model predictive control (DMPC) technique with enhanced steady-state performance for power converters tied to the electric utility. The discrete space vector modulation (DSVM) method is considered in the design of the suggested DMPC, where virtual voltage vectors (VVs) besides the real ones are utilized for improving the steady-state response of the proposed controller. Furthermore, for averting the high computational burden and making the proposed control technique simple, a deadbeat (DB) function is employed for calculating the reference VV based on the required reference current. Subsequently, a discrete-time integral term is combined with this DB function to enhance the robustness of the suggested DMPC technique against variations of the model parameters. Finally, the best virtual or real VV is chosen by a certain quality function, which will be applied to the power converter in the next sample. The suggested technique is verified by simulation results and its performance is compared with the classical DMPC and voltage-oriented control (VOC).

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Solano, Javier, Diego Jimenez, and Adrian Ilinca. "A Modular Simulation Testbed for Energy Management in AC/DC Microgrids." Energies 13, no. 16 (August 5, 2020): 4049. http://dx.doi.org/10.3390/en13164049.

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This paper introduces a modular testbed to simulate AC/DC microgrids. The testbed is implemented in Matlab Simulink and is based on the energetic macroscopic representation (EMR) formalism. It is designed to be a tool to evaluate energy management strategies in AC/DC microgrids. The microgrid simulation model includes a photovoltaic generator, a fuel cell system, ultracapacitors, and batteries on the DC side. It includes voltage source converters (VSC) to couple the DC side with the AC side of the microgrid, which includes a variable AC load and a synchronous generator. Two case studies illustrate the use of the testbed. The model is implemented in Matlab Simulink and made openly available for the scientific community. Using this model, researchers can develop and evaluate energy management strategies in AC/DC microgrids.

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Wing-Chi So, C. K. Tse, and Yim-Shu Lee. "Development of a fuzzy logic controller for DC/DC converters: design, computer simulation, and experimental evaluation." IEEE Transactions on Power Electronics 11, no. 1 (January 1996): 24–32. http://dx.doi.org/10.1109/63.484413.

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Guo, Xizheng, Jiaqi Yuan, Yiguo Tang, and Xiaojie You. "Hardware in the Loop Real-Time Simulation for the Associated Discrete Circuit Modeling Optimization Method of Power Converters." Energies 11, no. 11 (November 21, 2018): 3237. http://dx.doi.org/10.3390/en11113237.

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Due to the complicated circuit topology and high switching frequency, field-programmable gate arrays (FPGA) can stand up to the challenges for the hardware in the loop (HIL) real-time simulation of power electronics converters. The Associated Discrete Circuit (ADC) modeling method, which has a fixed admittance matrix, greatly reduces the computation cost for FPGA. However, the oscillations introduced by the switch-equivalent model reduces the simulation accuracy. In this paper, firstly, a novel algorithm is proposed to determine the optimal discrete-time switch admittance parameter, Gs, which is obtained by minimizing the switching loss. Secondly, the FPGA resource optimization method, in which the simulation time step, bit-length, and model precision are taken into consideration, is presented when the power electronics converter is implemented in FPGA. Finally, the above method is validated on the topology of a three-phase inverter with LC filters. The HIL simulation and practicality experiments verify the effect of FPGA resource optimization and the validity of the ADC modeling method, respectively.

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Yang, Bin, Kangli Liu, Sen Zhang, and Jianfeng Zhao. "Design and Implementation of Novel Multi-Converter-Based Unified Power Quality Conditioner for Low-Voltage High-Current Distribution System." Energies 11, no. 11 (November 14, 2018): 3150. http://dx.doi.org/10.3390/en11113150.

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This paper introduces a novel multi-converter-based unified power quality conditioner (MCB-UPQC). Three optimization methods are proposed based on the traditional UPQC: (1) The shunt converter is substituted with multi-modular parallel converters. Hence, the reactive power and harmonic currents can be increased greatly, which are suitable for low-voltage high-current distribution systems. (2) The series converters consist of three H-bridge inverters, and each of the H-bridge inverters is controlled separately. The control strategy is easier to achieve and can improve the control performance of voltage regulation under unbalanced voltage sag or swell. (3) A three-phase four-leg (3P4L) converter is connected to the common DC bus of the proposed UPQC to connect the renewable energy and energy storage system. The detailed mathematical models of shunt and series converters are analyzed, respectively. A multi-proportional resonant (PR) controller is presented in the voltage regulation and reactive power compensation control algorithms. The simulation results verify the feasibility of the control algorithms. Finally, the experimental platform is established, and the experimental results are presented to verify the validity and superiority of the proposed topology and algorithms.

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Tian, Xu, Yue Ma, Jintao Yu, Cong Wang, and Hong Cheng. "A Modified One-Cycle-Control Method for Modular Multilevel Converters." Energies 12, no. 1 (January 3, 2019): 157. http://dx.doi.org/10.3390/en12010157.

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In this paper, a new One-Cycle-Control (OCC) method is designed for a modular multilevel converter (MMC) based on the principle of the equivalent resistance constant. The proposed controller has a simple structure and a small amount of calculation by cancelling the current inner loop proportional integral (PI) controller and the inverse transform in the traditional direct-quadrature (DQ) control. Compared to the traditional OCC controller, the new one separates the control method from the modulation strategy, making it possible to use not only carrier-based pulse-width modulation (PWM), but also nearest level modulation PWM to generate drive signals. Besides, the independent control of the active and the reactive power is implemented by injecting a reference current with the same phase of the supply voltage or a reference current which lags the supply voltage by π/2 into the controller, so the converter can operate in four quadrants and it can work in either a grid-connect or off-grid environment. The feasibility and the performance of the proposed OCC method have been validated by both the simulation under the MATLAB/SIMULINK (R2012a) environment and experimental results.

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Lemu, Hirpa G. "Simulation-Based Engineering Approaches for Renewable Energy Conversion Systems." Advanced Materials Research 1039 (October 2014): 91–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1039.91.

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The article provides a brief overview of the existing simulation-based engineering approaches with main focus on applications in analysis and simulation of renewable energy conversion systems. Among available numerical simulation tools, the study focuses on finite element analysis and multibody dynamics simulation techniques that are currently attracting the major research attention. Any mechanical simulation task presupposes existence of a simulation model, commonly in a computer-aided design tool. Thus, the approach used to merge design data with other computer-aided engineering environment is discussed and elaborated. This approach is particularly beneficial for design optimization of wind and wave converters to be installed at harsh and unfriendly environment for testing physical prototypes.

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Journal articles on the topic 'Thermionic converters – Computer simulation'

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