scholarly journals Pre-filtered synchronization structure for grid-connected power converters to reduce the stability impact of PLL dynamics

2020 ◽  
pp. 1-1
Author(s):  
J. Ignacio Garcia ◽  
J. Ignacio Candela ◽  
Pedro Catalan
Keyword(s):  
Power Converters ◽  
The Stability ◽  
Synchronization Structure

scholarly journals Selection and Validation of Mathematical Models of Power Converters using Rapid Modeling and Control Prototyping Methods

2018 ◽  
Vol 8 (3) ◽  
pp. 1551 ◽  
Author(s):  
Fredy Edimer Hoyos ◽  
John Edwin Candelo ◽  
John Alexander Taborda
Keyword(s):  
Power Converters ◽  
Experimental Tests ◽  
Power Converter ◽  
Buck Converter ◽  
Experimental Results ◽  
Mathematical Representation ◽  
Modeling And Control ◽  
Rapid Control Prototyping ◽  
The Stability ◽  
And Control

This paper presents a methodology based on two interrelated rapid prototyping processes in order to find the best correspondence between theoretical, simulated, and experimental results of a power converter controlled by a digital PWM. The method supplements rapid control prototyping (RCP) with effective math tools to quickly select and validate models of a controlled system. We show stability analysis of the classical and two modified buck converter models controlled by zero average dynamics (ZAD) and fixed-point induction control (FPIC). The methodology consists of obtaining the mathematical representation of power converters with the controllers and the Lyapunov Exponents (LEs). Besides, the theoretical results are compared with the simulated and experimental results by means of one- and two-parameter bifurcation diagrams. The responses of the three models are compared by changing the parameter K_s of the ZAD and the parameter N of the FPIC. The results show that the stability zones, periodic orbits, periodic bands, and chaos are obtained for the three models, finding more similarities between theoretical, simulated, and experimental tests with the third model of the buck converter with ZAD and FPIC as it considers more parameters related to the losses in different elements of the system. Additionally, the intervals of the chaos are obtained by using the LEs and validated by numerical and experimental tests

scholarly journals The Control Parameter Determination Method for Bidirectional DC-DC Power Converters Interfaced Storage Systems Based on Large Signal Stability Analysis

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1018 ◽  
Author(s):  
Liu ◽  
Bian ◽  
Cao ◽  
Zhang ◽  
Meng
Keyword(s):  
Control Parameter ◽  
Power Converters ◽  
Storage Systems ◽  
Parameter Determination ◽  
Determination Method ◽  
Large Signal ◽  
Signal Stability ◽  
Dc Power ◽  
The Stability ◽  
Storage Units

In DC microgrid (DC-MG), the loads connected with converters under strict control areconsidered as CPLs (constant power loads). When the voltage of CPLs decreases, the currentincreases and the negative impedance characteristic of CPLs cause instability easily. Fortunately,appropriate control for energy storage units could improve the system stability. However, mosttraditional control methods for bidirectional DC-DC power converters (BDC) connected withbattery storage units do not quantitatively consider the stability influences of control parameters.This paper quantitatively analyzes the stability influence of the BDC current-mode controlparameters and the negative impact of CPLs and derives the control parameter determinationmethod for BDC interfaced storage systems. Large signal stability constraints are obtained in termsof mixed potential function. According to the constraints, the large signal stability is improved whenthe BDC control parameter kp increases, while the stability is degraded when the power of CPLsincreases. The control parameter determination method is very effective and convenient to apply,and the appropriate parameter kp for BDC is determined. The regions of asymptotic stability (RAS)identify that the proposed control parameter determination method could improve the systemstability effectively. The determination method is fully verified by the simulation and experimental results.

scholarly journals Enhancing the Stability of the Switched Systems Using the Saltation Matrix

2019 ◽  
Vol 19 (05) ◽  
pp. 1941004 ◽  
Author(s):  
Juan-Guillermo Muñoz ◽  
Arnold Pérez ◽  
Fabiola Angulo
Keyword(s):  
Differential Equations ◽  
Analytical Solutions ◽  
Switched Systems ◽  
Power Converters ◽  
Piecewise Linear ◽  
Power Converter ◽  
Entire System ◽  
Algebraic Equations ◽  
Linear Differential ◽  
The Stability

Controlling switched systems is a difficult task, even when dealing with piecewise linear systems (CPWLs), which consist of a set of linear differential equations and a set of switching conditions. This difficulty is largely due to the loss of linearity in the entire system, and it is necessary to solve differential and algebraic equations to determine the solution. In this paper, a new method to tune the parameters of the controllers applied to switched systems is derived using information from the saltation matrix, particularly its induced norm. First, the parameters are tuned using classical methods, and then, after analyzing the norm of the saltation matrix, a new set of parameters that guarantees the stability of the period-1 orbit is obtained. The method is validated using analytical solutions for two different systems (boost and boost-flyback power converters) and is also experimentally validated for the boost-flyback power converter.

scholarly journals Recent advances in phase-locked loop based synchronization methods for inverter-based renewable energy sources

2020 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Haval Sardar Kamil ◽  
Dalila Mat Said ◽  
Mohd Wazir Mustafa ◽  
Mohammad Reza Miveh ◽  
Nasarudin Ahmad
Keyword(s):  
Renewable Energy ◽  
Power Converters ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Phase Locked Loop ◽  
Energy Sources ◽  
Comprehensive Review ◽  
Grid Synchronization ◽  
Voltage Phase ◽  
The Stability

<p>Recently, researchers have shown an increased interest in renewable energy sources (RESs) to improve power quality, reliability and stability of the power system. However, RESs require proper control strategies to ride through grid disturbances and stay connected to the main grid for the stability contribution. Moreover, the control of them relies mainly on the synchronization algorithms to precisely detect the voltage phase angle, magnitude and frequency. Throughout the years, various synchronization schemes have been introduced and developed. In the renewable-based generation sources, the phase-locked loop (PLL) is a well-known technique for operating grid-tied power converters for the estimation of the synchronization information and grid voltage monitoring. This paper aims to provide a comprehensive review of the recently developed PLL algorithms for grid synchronization applications. At first, various estimation techniques are discussed. Then, a comparison between various PLLs and possible future works are recommended.</p>

scholarly journals Performance Analysis of a Peak-Current Mode Control with Compensation Ramp for a Boost-Flyback Power Converter

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Juan-Guillermo Muñoz ◽  
Guillermo Gallo ◽  
Gustavo Osorio ◽  
Fabiola Angulo
Keyword(s):  
Closed Loop ◽  
Power Converters ◽  
Monodromy Matrix ◽  
Current Mode ◽  
Power Converter ◽  
Dynamical Analysis ◽  
Dynamical Equations ◽  
Peak Current ◽  
Operation Conditions ◽  
The Stability

High voltage gain power converters are very important in photovoltaic applications mainly due to the low output voltage of photovoltaic arrays. This kind of power converters includes three or more semiconductor devices and four or more energy storage elements, making the dynamical analysis of the controlled system more difficult. In this paper, the boost-flyback power converter is controlled by peak-current mode with compensation ramp. The closed-loop analysis is performed to guarantee operation conditions such that a period-1 orbit is attained. The converter is considered as a piecewise linear system, and the closed-loop stability is determined by using the monodromy matrix, obtained by the composition of the saltation matrixes with the solutions of the dynamical equations in the linear intervals. The largest eigenvalue of the monodromy matrix gives the stability of the period-1 orbit, and a deep analysis using bifurcation diagrams let us reach a conclusion about the loss of the stability, which is experimentally verified. To avoid overcompensation effects, the minimum value required by the compensation ramp is obtained, and the minimum and maximum values of the load resistance are found too. The system has a good transient response under disturbances in the load and in the input voltage.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

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