Edith Clavel

Original cabling conditions to insure balanced current during switching transitions between paralleled semiconductors

This paper deals with the problem of paralleling components. First, general investigations concerning the influence of stray inductances on the current and voltage differences between n paralleled components are presented. Original cabling conditions are deduced to insure balanced electrical constraints. Then, a power module involving two paralleled MOSFETs is analysed. To validate the original presented conditions, two different choppers, involving paralleled power modules have been built, with different layouts. Experimental and simulated results confirm the validity of the proposed rules.

EMC Modeling of an Industrial Variable Speed Drive With an Adapted PEEC Method

This paper presents an adapted partial element equivalent circuit (PEEC)-based methodology applied to the modeling of interconnections of power electronics devices. Although this method is already well known, the originality of this work is its use to model a device presenting an industrial complexity. To make possible this modeling, two adapted integral methods, based on two different meshings, are presented. They are dedicated respectively to the computation of parasitic inductances and capacitances and lead to an equivalent circuit of the system. From a time-domain simulation of this circuit, current and voltage sources can be extracted and used to compute the radiated near magnetic field. This approach has been applied to model a real industrial static converter via system couplings, a variable speed drive. Good agreements have been obtained between simulated and measured results on conducted and emitted electromagnetic analysis.

MoM and PEEC Method to Reach a Complete Equivalent Circuit of a Static Converter

This paper presents an application of the Method of Moments (MoM), to compute parasitic capacitances of a power electronics layout. By coupling these capacitances to a resistive and inductive equivalent circuit obtained thanks to Partial Element Equivalent Circuit (PEEC) method, a complete electrical equivalent circuit made of lumped elements is obtained. Its simulation by means of a SPICE-like tool enables the evaluation of the EMC efficiency of a power electronics structure. This method is applied to a boost converter and the results obtained by numerical simulation (MoM and finite element method - FEM) are compared to measurements. Finally, radiated EMC investigations are presented thanks to circuit simulation and measurements.

Numerical methods for eddy currents modeling of planar transformers

Having many advantages compared to classic wire wound technology; planar magnetic components are largely used. Modeling tools are required to help designers for less time consuming conception. Nevertheless, number of adapted modeling solutions is limited by the complexity of such geometries. The determination of appropriate description (2D or 3D) for eddy currents modeling and by this way AC copper losses evaluation are investigated in this paper. The validity of the approach is successfully presented on an industrial application from the current evaluation until thermal simulations.

Modeling of Connections Taking Into Account Return Plane: Application to EMI Modeling for Railway

The modeling of electrical characteristics of connections is an important stage of the design phase of a structure. Indeed, they have an impact on the current density distributions inside conductors as well as on the current distributions when several components are connected in parallel. In the case of a return plane in the studied structure as for power electronics converters or railway applications, the model of connections has to be improved in order to represent the physics better. For the first application field, the cooling system itself can be a ground plane, and for the second one, the earth has to be modeled. This paper presents different ways to take into account a return plane while modeling the electrical equivalent circuit of connections above it. It starts with the simplest one, the image method, and continues with the use of a complex skin depth result of solving the Carson integral.

Determination of the layout influence on the effectiveness of a three-phase common mode filter by using equivalent circuits and PSpice

Conducted and radiated disturbances of motor driver associations are due to differential and common mode currents. Common mode filters are usually used to evacuate common mode currents from the static converter to the earth. In consequence, such structures play a main role in disturbance reduction and are widely used in industry. However, stray elements of components and layout can reduce the filtering effectiveness. A modeling method taking into account all stray elements of industrial multilayer structures is presented. A three-phase common mode filter is modeled and optimized. This filter is implemented in a four layers industrial motor driver. The common mode inductance is modeled using complex inductive equivalent model. The layout impedance is computed using PEEC method. The electric computing is achieved using Spice.

Modeling the near-field coupling of EMC filter components

EMC filters are increasingly integrated into power applications. To improve the filter performance it is important to model the electromagnetic interference between components to optimize their positions. In this paper, a method is proposed to construct the equivalent model of the filter components. The proposed method proposed is based on the multipolar expansion by representing the radiation emission of generic structures in a spherical reference (r, θ, ϕ). These models of the sources will be used to compute the mutual inductance between the components according to their layout.

Conducted and radiated EMI characterisation of power electronics converter

With increasing use of switching power supplies in industrial applications and the necessity to respect standards, problems of electromagnetic compatibility have to be solved. In order to reduce the number of prototypes, costs and delays, it is necessary to evaluate and to measure the characteristics of the structure. For this, a modelling process has been developed to foresee the behaviour of the structure and evaluate its conducted and radiated emissions. This process is presented through the study of a buck converter structure. Results of the modelling are quite interesting since the wave forms of the structure can be predicted.

Magnetic field computation of a common mode filter using Finite Element, PEEC methods and their coupling

The layout and wounded components are sources of radiated perturbations in static converters. Used to reduce conducted perturbations, common mode filters can be responsible of the incompliance to radiated standards. Magnetic field computation of common mode filters allows defining their radiated perturbation level during the definition. This allows earning time considering the design process of the whole system (static converter-filter-driver) is an important gain of time. An original modeling method is presented. The common mode inductance is modeled using finite element method. The layout is modeled using partial element equivalent circuit (PEEC) method. Then, the PEEC model is imported into the finite element one. By this way, interaction phenomena between the inductance and the layout are modeled.

How to better know what happens inside a power multi chip module

In this paper, the way to provide an electrical equivalent scheme for any power multi chip module (PMCM) is presented. Considering the geometrical description of the PMCM, an electrical R, L, M circuit is automatically generated using a special software, InCa. This circuit can be used either directly in a PSPICE simulation, or to analyse technical parameters like switching cell inductance, interaction between power and drive circuit or current unbalance in the PMCM.