Capacitive Behavior of HF Power Transformers: Global Approach to Draw Robust Equivalent Circuits and Experimental characterization

International audienceThis paper addresses the representation and the characterization of the electrostatic behavior of n-windings HF power transformers. A global approach, mainly based on energy considerations about linear electrostatic circuits, is introduced. It leads to equivalent circuits which include minimum numbers of elements. Besides, owing to a special approximation that is often acceptable, the general circuit can be greatly simplified and so it is for the experimental identification. This is discussed. Then, knowing the topology of the needed circuits, we show how to experimentally find the values of all involved components. This is achieved by using a wide frequency range impedance analyzer according to a well defined process. An industrial 3-winding transformer is used to illustrate this identification process and, finally, curves related to the equivalent circuit are compared to experimental ones

Lumped parameter modeling to improve planar transformers design

International audienceThis paper presents a modeling and simulation tool based on a 1D modeling of planar transformers. The main goal is to help designers to easily describe, simulate and improve a planar transformer

Simulation and optimization tool for high-frequency planar transformers based on 1D analytical modelling

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Analytical Modeling of Losses for High Frequency Planar LCT Components

International audiencePassive components occupy a major part of the volume of power electronic converters. Therefore to increase the converter power density, designers have to carefully reduce the size of these components. The integrated planar inductorcapacitor- transformer, already known as LCT component can achieve this goal. Volume optimization of this component requires an accurate analytical modeling of overall losses (including magnetic, copper and the dielectric parts). However, common methods could not be used for high frequency planar components. In the first part of this paper, we introduce the principle and applications of LCT components. In the second part, we present an analytical electromagnetic and electrostatic modeling for high frequency planar components - the lumped elements equivalent circuit method. This method has been developed for components having simple geometries. The efficient application of this method to the complex geometry of LCT is showed in the third part

Complete Analytical Calculation of Static Leakage Parameters: A Step Toward HF Transformer Optimization

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New μPEEC formulation for modeling 2D core,transformer. Principles, academic and industrial applications

International audienceThis paper presents a new μPEEC formulation that suits for modeling 2D ferrite core transformers. μPEEC method is based on the representation of magnetic materials by equivalent current densities flowing, for insulating ferrites, on the surface of the core. Firstly, the limits of available μPEEC algorithms are pointed out and improvements are achieved to overcome calculation inaccuracies linked to magnetic angular cavities (windows) dug in power electronics transformers. Secondly, the new μPEEC formulation is implemented and used to evaluate the specific inductance per turns squared (Al) of a 9kVA, 290g, 3-winding planar transformer core and results are compared to core manufacturer data. Finally, interest for power electronics engineers of having a fast and accurate computing method for designing inductors and transformers is highlighted

Perméabilité complexe équivalente pour représenter les pertes par proximité dans les conducteurs

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