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The purpose of this paper is to develop the method of taking the eddy current losses in the laminated magnetic circuits into account during implicit transient calculations. The nonlinear magnetization characteristic of iron and the hysteresis losses can also be considered in the simulations done with the developed method.

The paper presents complex equivalent magnetic permeability derived from the presumed angular frequency in a laminated magnetic circuit. On this basis, the synthesis of a magnetic permeability as a function of the Laplace variable “s” is presented. After transformation of the variable “s” to a variable “z” of the Z transformation, it is possible to conduct discrete time calculation of transient states of magnetic circuits including the eddy current losses. An iterative process is developed to take the saturation of the magnetic circuit in these calculations into account. As regards hysteresis losses, the scalar model of magnetic hysteresis by Juhani Tellinen was implemented. The new method is validated by calculations of a two-coil transformer.

It is important to take into account the losses in sheet metal directly in the implicit transient calculations. This possibility is provided by the presented method based on the synthesis of the equivalent magnetic permeability μ^(s). The presented method was proved to be correct and efficient. The calculated sheet metal losses were compared with the results presented in literature. Good conformance of results was attained.

The method enables calculation of eddy current and hysteresis losses in laminated magnetic circuits during calculations of transient states. It does not need, unlike the previous methods, previously provided information (“a priori”) about the content of higher harmonics in waveforms. The method takes into account mutual dependence of transient waveforms of currents in the analysed system and losses of laminated magnetic circuit, expressed by eddy currents and hysteresis losses. Its implementation comes down to using in calculations a filter of the IIR type and corresponds to its calculation complexity. The author plans to use the presented method in the finite elements method transient calculations.

A new approach is a synthesis of the equivalent magnetic permeability in Laplace domain, which creates an equivalent RC circuit for permeability. Analytic equations for parameters of this equivalent circuit are original. A method for considering nonlinear magnetization characteristic and hysteresis losses was presented. In calculations of transient states of systems with magnetic circuits, one can use the developed equivalent circuit of magnetic permeability in a form of the IIR filter. Operator magnetic permeability includes fractional derivative of Laplace’s variable “vs”. Therefore, the equivalent IIR filter includes “history” of the processes that take place in the laminated magnetic circuit to the current, calculated time moment. This “history” in terms of its content is limited only by the degree of the applied IIR filter. It enables to calculate “step by step”, without previous (“a priori”) knowledge about harmonic components of the whole waveforms. It was necessary in the previously used methods, when determining parameters of magnetic permeability. The method proposed in the paper allows for calculations with taking into account direct dependence of an electric part of the system on its magnetic part.

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

The time of tightly coupled transient calculation and the accuracy of conventional loosely coupled algorithm make it difficult to meet the engineering design requirements for long-term conjugate heat transfer (CHT) problems. The purpose of this paper is to propose a new loosely coupled algorithm with sufficient accuracy and less calculation time on the basis of the quasi-steady flow field. Through this algorithm, it will be possible to reduce the update frequency of the flow field and devise a strategy by which to reasonably determine the update steps.

In this paper, the new algorithm updates the flow field by solving the steady governing equations in the fluid region and by calculating the transient temperature distribution until the next update of the fluid flow, by means of solving the transient energy equations in the entire computational domain. The authors propose a strategy by which to determine the update step, by using the engineering empirical formula of the Nusselt number, on the basis of the changes of the inlet and outlet boundary conditions.

Taking a duct heated by an inner forced air flow heating process as an example, the comparison results for the tightly coupled transient calculation by Fluent software shows that the new algorithm is able to significantly reduce the calculation time of the transient temperature distribution with reasonable accuracy. For example, the respective computing times are reduced to 22.8 and 40 per cent, while the duct wall temperature deviations are 7 and 5 per cent, using the two flow update time steps of 100 and 50 s on the variable inlet-flow rate conditions.

The new algorithm outlined in this paper further improves the calculated performance and meets the engineering design requirements for long-term CHT problems.

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

The purpose of this study is to explore the transient characteristics of mixed-flow pumps during startup process.

This study uses a full-flow field transient calculation method of mixed-flow pump based on a closed-loop model.

The findings show the hydraulic losses and internal flow characteristics of the piping system during the start-up process.

Large computational cost.

Improve the accuracy of current numerical simulation results in transient process of mixed-flow pump.

Simplify the setting of boundary conditions in the transient calculation.

A half‐implicit absolutely stable method for 3D simulation of the transient processes in semiconductor devices is proposed. The calculations of transient processes in bipolar transistor were carried out and were compared with the results of 2D simulation.

The current distribution within multi strand windings is investigated for transient current and voltage supplies. The difference in losses between transient and sinusoidal waveforms is elaborated. Therefore, a wide range of frequencies as well as different kinds of transient waveforms has been investigated. The definition of the skin depth is no longer sufficient. A new parameter is required for transients, which is related to time. This parameter will be defined and called “skin time”. A numerical method is developed based upon a finite element transient calculation. The method is applied to the winding as well as to the core. A comparison with measurements verifies the approach described.

To study very fast transients in transformers, it is required to compute the inductance matrix of windings at very high frequencies (MHz). The core acts as a flux barrier at very high frequencies, affecting the values of the self and mutual inductances of windings. In the previous work by the authors, analytical methods for computation of the inductance matrix at very high frequencies, using a 2-D planar approximation of the transformer geometry, were presented. The purpose of this paper is to present analytical methods for the same problem in cylindrical coordinates which do not suffer from the previous approximations in geometry.

A method based on the Fourier integral transform is described for the calculation of inductance outside the core window. For the region inside the core window, inductance formulas are extracted using the Fourier series analysis.

The final expressions are accurate and fast convergent. Comparisons with FEM simulations and previous 2-D planar formula prove the excellent accuracy of the proposed inductance formulas.

The value of the presented formulas accounts for considering the effect of iron core on inductances in transformer very fast transient analysis.

WHERE computer programmes are not available for the solution of kinetic heating problems, the estimation of equilibrium and transient surface temperatures on bodies in supersonic flow becomes tedious, especially where the transient conditions are to be analysed. A current method of performing these calculations for a turbulent boundary layer is here synthesised into nomogram form.

The purpose of this paper is to describe a systematic investigation of the currents, torques and other electromagnetic quantities in a machine after different short circuits by the means of coupled numerical field and network calculation. The behaviour of a synchronous machine after a stator‐winding fault still is a little known issue. Nevertheless, the occurrence of winding faults can damage the stator winding of the machine severely and may also destroy the whole stator core. Therefore, there exists a strong need for reliable calculation methods for the evaluation of these faults, e.g. the reconstruction of the details of an accident.

The paper discusses an analytical approach which calculates all possible winding connections when absence of nonlinear material behaviour is assumed and nonlinearity is only considered by adjusting the inductances after solving the differential equations. In the following, a more accurate method is given by the numerical field calculation, considering a two‐dimensional time variant permeability distribution on the cross‐section of an electrical machine.

First results of transient time‐stepping calculations of short circuits with special respect on winding currents and radial forces on the rotor are presented.

The approach presented in this paper can be applied in the field of R&D for the dimension of electrical machines and its protection system as well as for the investigation of possible sources of an occurred machine failure.

The bulk of publications that contribute to the topic of inner winding faults are comprised of derivations of analytical models with the assumption of linear material behaviour. The paper puts strong emphasis on the consideration of the nonlinearity.