scholarly journals Development of Frequency Weighted Model Reduction Algorithm with Error Bound: Application to Doubly Fed Induction Generator Based Wind Turbines for Power System

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 44
Author(s):  
Sajid Bashir ◽  
Sammana Batool ◽  
Muhammad Imran ◽  
Muhammad Imran ◽  
Mian Ilyas Ahmad ◽  
...  
Keyword(s):  
Model Reduction ◽  
State Space ◽  
Frequency Spectrum ◽  
Wind Turbines ◽  
Order Reduction ◽  
Synchronous Generator ◽  
The State ◽  
Variable Speed ◽  
Balanced Realization ◽  
Frequency Weighting

The state-space representations grant a convenient, compact, and elegant way to examine the induction and synchronous generator-based wind turbines, with facts readily available for stability, controllability, and observability analysis. The state-space models are used to look into the functionality of different wind turbine technologies to fulfill grid code requirements. This paper deals with the model order reduction of the Variable-Speed Wind Turbines model with the aid of improved stability preserving a balanced realization algorithm based on frequency weighting. The algorithm, which is in view of balanced realization based on frequency weighting, can be utilized for reducing the order of the system. Balanced realization based model design uses a full frequency spectrum to perform the model reduction. However, it is not possible practically to use the full frequency spectrum. The Variable-Speed Wind Turbines model utilized in this paper is stable and includes various input-output states. This brings a complicated state of affairs for analysis, control, and design of the full-scale system. The proposed work produces steady and precise outcomes such as in contrast to conventional reduction methods which shows the efficacy of the proposed algorithm.

On Improving Model Checking of Time Petri Nets and Its Application to the Formal Verification

2021 ◽  
Vol 12 (4) ◽  
pp. 68-84
Author(s):  
Naima Jbeli ◽  
Zohra Sbai
Keyword(s):  
Model Checking ◽  
Petri Nets ◽  
Formal Verification ◽  
State Space ◽  
Order Reduction ◽  
The State ◽  
Timing Constraints ◽  
Time Petri Nets ◽  
Explicit Timing ◽  
Class Graph

Time Petri nets (TPN) are successfully used in the specification and analysis of distributed systems that involve explicit timing constraints. Especially, model checking TPN is a hopeful method for the formal verification of such complex systems. For this, it is promising to lean to the construction of an optimized version of the state space. The well-known methods of state space abstraction are SCG (state class graph) and ZBG (graph based on zones). For ZBG, a symbolic state represents the real evaluations of the clocks of the TPN; it is thus possible to directly check quantitative time properties. However, this method suffers from the state space explosion. To attenuate this problem, the authors propose in this paper to combine the ZBG approach with the partial order reduction technique based on stubborn set, leading thus to the proposal of a new state space abstraction called reduced zone-based graph (RZBG). The authors show via case studies the efficiency of the RZBG which is implemented and integrated within the 〖TPN-TCTL〗_h^∆ model checking in the model checker Romeo.

Contribution of Variable-Speed Wind Turbines to Voltage Control

2002 ◽  
Vol 26 (6) ◽  
pp. 347-358 ◽  
Author(s):  
Pablo Ledesma ◽  
Julio Usaola
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Reactive Power ◽  
Voltage Control ◽  
Synchronous Generator ◽  
Induction Generator ◽  
Base Case ◽  
Variable Speed ◽  
Control Techniques ◽  
Control Schemes

Variable speed, grid connected, wind turbines open new possibilities for voltage control, because they use electronic converters, which may regulate the reactive power interchange with the grid. This paper proposes two voltage control schemes for variable speed wind turbines with double-fed induction generator. The first scheme acts on the wind-turbine power factor, while the latter acts directly on the converter current. Advantages and drawbacks of both techniques are discussed. Both control techniques have been tested by simulations of a base case, which represent a synchronous generator, a wind farm and a local load, and several disturbances such as the loss of compensator capacitors.

scholarly journals Comparative Study of the Effects of Machine Parameters on DFIG and PMSG Variable Speed Wind Turbines During Grid Fault

2021 ◽  
Vol 9 ◽  
Author(s):  
Kenneth E. Okedu ◽  
Maamar Al Tobi ◽  
Saleh Al Araimi
Keyword(s):  
Comparative Study ◽  
Wind Turbines ◽  
Computer Aided Design ◽  
Synchronous Generator ◽  
Operating Conditions ◽  
Variable Speed ◽  
Wind Generators ◽  
Fault Ride Through ◽  
Doubly Fed ◽  
The Stability

This study investigates the transient performance of two variable speed wind turbines (VSWTs), namely doubly fed induction generator (DFIG) and the permanent magnet synchronous generator (PMSG), that are widely employed in wind energy conversion, considering their machine parameters. The machine parameters of both wind turbines were changed considering different scenarios, while keeping other parameters constant, to study the behavior of the wind generators. This study was carried out using the same operating conditions of rated wind speed, based on the characteristics of both wind turbine technologies. The wind turbines were subjected to a severe three phase to ground bolted fault to test the robustness of their controllers during grid fault conditions. Efforts were made to carry out an extensive comparative study to investigate the machine parameters that have more influence on the stability of the different wind turbines considered in this study. Simulations were carried out using power system computer-aided design and electromagnetic transient including DC (PSCAD/EMTDC). Effective machine parameter selection could help solve fault ride-through (FRT) problems cost-effectively for both VSWTs, without considering the external circuitry of and changing the original architecture of the wind turbines.

A Direct Approach to Order Reduction of Nonlinear Systems Subjected to External Periodic Excitations

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Sangram Redkar ◽  
S. C. Sinha
Keyword(s):  
Nonlinear Systems ◽  
State Space ◽  
Invariant Manifold ◽  
Large Scale ◽  
Reduction Process ◽  
Order Reduction ◽  
The State ◽  
Reduced Order Models ◽  
External Excitation ◽  
Reduced Order

In this work, the basic problem of order reduction of nonlinear systems subjected to an external periodic excitation is considered. This problem deserves special attention because modes that interact (linearly or nonlinearly) with external excitation dominate the response. These dominant modes are identified and chosen as the “master” modes to be retained in the reduction process. The simplest idea could be to use a linear approach such as the Guyan reduction and choose those modes whose natural frequencies are close to that of external excitation as the master modes. However, this technique does not guarantee accurate results when nonlinear interactions are strong and a nonlinear approach must be adopted. Recently, the invariant manifold technique has been extended to forced problems by “augmenting” the state space, i.e., forcing is treated as an additional state and an invariant manifold is constructed. However, this process does not provide a clear picture of possible resonances and conditions under which an order reduction is possible. In a direct innovative approach suggested here, a nonlinear time-dependent relationship between the dominant and nondominant states is assumed and the dimension of the state space remains the same. This methodology not only yields accurate reduced order models but also explains the consequences of various primary and secondary resonances present in the system. One obtains various reducibility conditions in a closed form, which show interactions among eigenvalues, nonlinearities and the external excitation. One can also recover all “resonance conditions” obtained via perturbation or averaging techniques. The “linear” as well as the “extended invariant manifold” techniques are applied to some typical problems and results for large-scale and reduced order models are compared. It is anticipated that these techniques will provide a useful tool in the analysis and control of large-scale externally excited nonlinear systems.

Power Analysis Using Various Types of Wind Turbines

2022 ◽  
pp. 271-286
Author(s):  
Bibhu Prasad Ganthia ◽  
Monalisa Mohanty ◽  
Jai Kumar Maherchandani
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Synchronous Generator ◽  
Type I ◽  
Variable Speed ◽  
Type Iv ◽  
Wind Turbine System ◽  
Simulation Based ◽  
Wind Power Systems

This chapter highlights on the design, operation, and comparative analysis of different types of wind turbine systems with respect to steady state and transient phenomenal activities under rapid wind speed variations. Here, Type I, which is fixed speed induction generator based, and Type II, which is DFIG based, variable speed operated systems are initially compared. In the next part, Type III wind turbine system is presented, which uses DFIG; later, it is compared with the Type IV WT system, which uses permanent magnet synchronous generator. This chapter provides a comparative overview on existing wind power systems including an analytic discussion of key principles and innovations for wind turbines. In this energy conversion system, various designs of wind turbines, pitch angle controlled based variable speed wind turbines governed by help of electronic power converters, were preferred. This scope of dynamic simulation-based study is implemented using MATLAB Simulink to convey the feasibility of the proposed wind turbine models.

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