Influence of saturation levels on transformer equivalent circuit model

This paper presents a modelling approach for a transformer with different saturation levels. First, the magnetic field distributions at different saturation levels in the transformer are analyzed by using numerical simulations. Then, the characteristics of the leakage magnetic flux are analyzed, and the magnetic circuits with varying leakage reluctance topologies are modeled. Finally, based on the mature duality relationship between electric and magnetic circuits, the equivalent electric circuit models are obtained. These kinds of models embody the effect of different saturation levels on the connection points of the leakage flux branches, and it can fully reflect the various working states of the transformer. The accuracy of the models is verified by comparing the circuit simulation results with those of FEM transient simulations.

Modeling and Diagnostic of Permanent Magnet Synchronous Machine under Insulation Failure Condition

One of the most frequent faults in PMSM stator is the turn-to-turn short-circuit fault. So, the aim of this paper is to present a dynamic model for PMSM with turn-to-turn short-circuit fault based on equivalent electric circuit model. Two simple and useful diagnostic techniques ESA an EPVA based on frequency analysis are applied to detect this kind of fault. The accuracy of diagnosis is based on adding the real waveform of back-EMF.

Mathematical modeling of the equivalent electric circuit of the electromagnetic drive of a high-voltage circuit breaker and its computer simulation in the Statistica software

Магнитные системы могут быть представлены в виде электрических цепей, поскольку закономерности и уравнения, описывающие процессы в проводниках магнитных и электрических величин, во многом идентичны. Это связано с близкой природой этих явлений. При этом переход к эквивалентной электрической схеме позволяет производить модельные эксперименты с меньшей затратой вычислительных ресурсов. Воспользовавшись электрической схемой замещения электромагнитного привода высоковольтного выключателя, произведен эксперимент, результаты которого проанализированы методами математической статистики, благодаря чему получены регрессионное уравнение. На основе этого уравнения можно рассчитывать магнитодвижущую силу, возникающую в подвижном якоре электромагнитного привода.

Engineering Aspheric Liquid Crystal Lenses by Using the Transmission Electrode Technique

The transmission electrode technique has been recently proposed as a versatile method to obtain various types of liquid-crystal (LC) lenses. In this work, an equivalent electric circuit and new analytical expressions based on this technique are developed. In addition, novel electrode shapes are proposed in order to generate different phase profiles. The analytical expressions depend on manufacturing parameters that have been optimized by using the least squares method. Thanks to the proposed design equations and the associated optimization, the feasibility of engineering any kind of aspheric LC lenses is demonstrated, which is key to obtain aberration-free lenses. The results are compared to numerical simulations validating the proposed equations. This novel technique, in combination with the proposed design equations, opens a new path for the design and fabrication of LC lenses and even other types of adaptive-focus lenses based on voltage control.

Mixed mode oscillations in an electrochemical reactor

This paper subject focuses on modelling of electrochemical processes during a deposition of nanostructured materials on a metallic substrate. Fundamentals of electrocrystallization processes and parameters influenced the final quality of the resulting products are considered. To quantify the evolution of the electrochemical reactor processes with respect to time, an equivalent electric circuit has been established. Two types of periodic supplying currents were taken into consideration: bipolar pulse current and sinusoidal rectified current. Results of performed computer simulations of electrocrystallization processes with the focus on mixed mode oscillations (MMOs) as the dynamical switches between small amplitude oscillations (SAOs) and large amplitude oscillations (LAOs) are presented. The established circuit model can lead to methods for fast treating large quantities of electrocrystallizator data and extracting from them kinetic parameters importantly influenced the structure of the produced materials.

МАКРОМОДЕЛИРОВАНИЕ СХЕМЫ ФАПЧ С ИСПОЛЬЗОВАНИЕМ ПОЛНОЙ ПРИНЦИПИАЛЬНОЙ СХЕМЫ ФАЗОВОГО ДЕТЕКТОРА

В работе рассмотрены проблемы анализа схем ФАПЧ с учетом наличия неидеальностей в схеме частотно-фазового детектора с токовым ключом. Для снижения затрат на моделирование предложено использовать эквивалентную электрическую схему, содержащую полную принципиальную схему ЧФД и схемные эквиваленты макромоделей остальных блоков ФАПЧ. The paper considers the problems of analyzing the PLL circuit taking into account the presence of nonidealities in the phase-frequency detector with a current key. To reduce the simulation efforts, it has been proposed to apply an equivalent electric circuit containing the complete schematic diagram of the PFD and circuit equivalents of the macromodels of other PLL blocks.