Compact modelling in circuit simulation: the general purpose analyser "OPTIMA 3"

Author(s):  
J. Ogrodzki ◽  
D. Bukat
1996 ◽  
Vol 2 (4) ◽  
pp. 295-302 ◽  
Author(s):  
BRUCE W. WATSON

Finite automata and various extensions of them, such as transducers, are used in areas as diverse as compilers, spelling checking, natural language grammar checking, communication protocol design, digital circuit simulation, digital flight control, speech recognition and synthesis, genetic sequencing, and Java program verification. Unfortunately, as the number of applications has grown, so has the variety of implementations and implementation techniques. Typically, programmers will be confused enough to resort to their text books for the most elementary algorithms. Recently, advances have been made in taxonomizing algorithms for constructing and minimizing automata and in evaluating various implementation strategies Watson 1995. Armed with this, a number of general-purpose toolkits have been developed at universities and companies. One of these, FIRE Lite, was developed at the Eindhoven University of Technology, while its commercial successor, FIRE Engine II, has been developed at Ribbit Software Systems Inc. Both of these toolkits provide implementations of all of the known algorithms for constructing automata from regular expressions, and all of the known algorithms for minimizing deterministic finite automata. While the two toolkits have a great deal in common, we will concentrate on the structure and use of the noncommercial FIRE Lite. The prototype version of FIRE Lite was designed with compilers in mind. More recently, computation linguists and communications protocol designers have become interested in using the toolkit. This has led to the development of a much more general interface to FIRE Lite, including the support of both Mealy and Moore regular transducers. While such a toolkit may appear extremely complex, there are only a few choices to be made. We also consider a ‘recipe’ for making good use of the toolkits. Lastly, we consider the future of FIRE Lite. While FIRE Engine II has obvious commercial value, we are committed to maintaining a version which is freely available for academic use.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 77 ◽  
Author(s):  
Johnatan M. Rodríguez-Serna ◽  
Ricardo Albarracín-Sánchez ◽  
Ming Dong ◽  
Ming Ren

Epoxy resin is one of the most common polymers used as part of the insulation system in key electrical assets such as power transformers and hydrogenerators. Thus, it is necessary to know their main characteristics and to evaluate their condition when subjected to High Voltage (HV). A brief review of epoxy resins’ applications as insulating materials is made, their main characteristics as insulating media are given, the improvements with nano-fillers are summarized and the main electric properties required for Partial Discharges (PD) modelling are listed. In addition, the theoretical background and state-of-the-art of the three-capacitance and analytical models for simulating PD in solid dielectrics, such as epoxy resins, are reviewed in detail. Besides, their main advantages and disadvantages are presented, some critical arguments to the modelling procedure and assumptions are made and some improvements are proposed, taking into account conclusions made from other authors using models related to the PD development process. Finally, a case study was simulated using a modified three-capacitance model and the analytical model. The PD rate, q-φ-n diagrams and the minimum, mean and maximum PD electric charge are compared with measurements reported in the literature. Simulation results are in reasonable agreement with measured values. Capacitance models can be implemented in general purpose electric circuit simulation packages; however, its simulation is computationally expensive. Additional to this, although the modified three-capacitance model is not as accurate as finite elements or analytical models, results are also in agreement with real data.


1995 ◽  
Vol 05 (04) ◽  
pp. 669-697 ◽  
Author(s):  
ROMUALD SZCZESNY ◽  
MIECZYSLAW RONKOWSKI

The methods, models and techniques — presented in the companion paper — have been used as a basis for the evaluation of popular general-purpose electrical circuit simulation programs, in particular, their applicability in the analysis of power electronic circuits. As a result of this critical evaluation, the general requirements for the simulation program adequate for converter systems studies and design have been formulated. On this basis the algorithm of TCAD — a general-purpose converter system simulation program — has been elaborated. In presentation of the TCAD program three parties have been distinguished: the first one emphasizes the applications of modern simulation methods for converter systems, the second describes briefly the features of the main modules of the TCAD package, and the third presents some simulation examples of practical converter systems. Three simulation examples are presented: two resonant converters and an induction motor drive fed by a full-bridge voltage source PWM inverter at normal and fault operation conditions. A good agreement between simulation and experimental results has proved that this simulation package is a power tool for research, teaching and engineering practice.


2005 ◽  
Vol 14 (03) ◽  
pp. 439-452
Author(s):  
MANGESH BORAGE ◽  
SUNIL TIWARI ◽  
SWARNA KOTAIAH

The parallel resonant scheme used to excite the magnets is characterized with high quality factor. The characteristic steep slope of the network gain near the resonant frequency makes the performance susceptible to the changes in component values. To accommodate the effect of varying component values, appropriate amplitude and phase over-drive capabilities in the ac source are required to maintain the magnet current of desired amplitude and in desired phase. A method of analysis of component tolerances using general purpose circuit simulation software, PSpice, is proposed in this letter. Using proposed normalized circuit description of the parallel resonant scheme, worst-case combination of component tolerances is determined. The evaluation of the effect of component tolerances in terms of required magnitude and phase over-drive of the ac source is presented under illustrative circuit conditions. Effect of various parameters on the over-drive is examined.


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