Jean-Michel Guichon

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.

Gate Circuit Layout Optimization of Power Module Regarding Transient Current Imbalance

The layout of power multichip modules is one of the key points of a module design, especially for high power densities, where coupling are enlarged. This paper focuses on dynamic current imbalance between paralleled chips. It can be principally attributed to gate circuit dissymmetry, which modifies inductances and coupling, especially with the power circuit. This paper describes the analysis of an existing power module, and based on a modification of the gate circuit geometry in an optimization procedure, shows how to improve the power module, in term of dynamic current repartition

Planar busbar optimization regarding current sharing and stray inductance minimization

The design of planar busbar as a must part of any present high power converter is particularly fine due to all electromagnetic phenomena which can not be easily predicted with appropriate simulation means. Among the numerous constraints which apply to this component, current sharing between all paralleled components (power IGBT modules and capacitors) and stray inductances responsible of both over-voltages and current unbalance are studied in the paper. Based on a dedicated inductive partial elements modeling the cabling rules are conceived and proposed following an optimization process is presented in order to achieve the optimal busbar design

Analysis of Electromagnetic Coupling and Current Distribution Inside a Power Module

Due to high-current commutation speed, it has become necessary to minimize stray inductances to reduce over-voltage. This is a great challenge for the power-converter designer. Integration of converters into ever smaller packages decreases stray inductance considerably but, at the same time, increases other phenomena (thermal issues and electromagnetic-compatibility disturbances) capable of decreasing reliability and efficiency of the system. This paper presents a generic equivalent cabling model and examines the impact of parasitic inductance on current-distribution imbalance. This paper could, therefore, be used in thermal analysis in order to better understand the influence of packaging.

Automatic layout optimization of an EMC filter

The transfer function of an EMC (Electro-Magnetic Compatibility) filter is strongly disturbed in high frequency due to stray electromagnetic phenomena. On the one hand the imperfections of the components but also all magnetic couplings on the other hand. Although these effects seem to be negative, it is possible to reduce the impacts of these imperfections on the filter response, and even to use them in order to improve its behavior. A proper arrangement of components and a clever layout of tracks are required. Nevertheless, the complexity of the problem makes unthinkable a manual construction. Therefore, this paper discusses the implementation of an automatic routing algorithm based on the PEEC method (Partial Equivalent Element Circuit), in order to consider the electro-magnetic aspect in the layout definition.

PWM Inverter Output Filter Cost-to-Losses Tradeoff and Optimal Design

This paper describes how to design the output filter of a pulsewidth-modulation inverter used in an uninterruptible power supply. Several constraints apply to this design: physical limitations of all material and components, output waveform quality, losses, cost, etc. All models used in the design process are described: semiconductor, inductor and capacitor losses, cost, total harmonic distortion, short-circuit behavior, etc. Input parameters are control law, switching frequency, inductor design parameters (number of turns and magnetic circuit), and capacitor values. Based on these design models, optimization is carried out, and cost-losses tradeoff curves are deduced. Two power levels (30 and 300 kVA) are taken as design example, with the same models, in order to show the robustness of the method.

Optimization of a DC Capacitor Tank

The choice of a set of capacitors for a dc link may be very different depending on the system requirements and user constraints. This paper shows how to achieve the best choice of a hybrid association of electrolytic capacitor and higher frequency technology (polyester for instance). Maximum allowed rms current in the electrolytic capacitor is obviously taken into account. The input filter of a buck converter is chosen as example. Various constraints are considered: voltage ripple, differential-mode electromagnetic-interference level, losses, weight, volume, surface, etc. Objective function for optimization is defined by the user and may be any of the previous parameters. The optimized result consists in the number and the values of components for both capacitor technologies.

An Integral Formulation for the Computation of 3-D Eddy Current Using Facet Elements

A volume integral formulation to compute eddy currents in nonmagnetic conductive media is presented. The current distribution is approximated with facet finite elements. The formulation is general and leads to an equivalent lumped elements circuit. To ensure the solenoidality of the current distribution, an algorithm detecting the independent loops is then used for the resolution. The formulation is tested on TEAM workshop Problem 7. Even with coarse meshes, its accuracy is demonstrated.

AN INDEPENDENT LOOPS SEARCH ALGORITHM FOR SOLVING INDUCTIVE PEEC LARGE PROBLEMS

This paper describes an original approach for determining independent loops needed for mesh-current analysis in order to solve circuit equation system arising in inductive Partial Element Equivalent Circuit (PEEC) approach. Based on the combined used of several simple algorithms, it considerably speed-up the loops search and enables the building of an associated matrix system with an improved condition number. The approach is so well-suited for large degrees of freedom problems, saving signiflcantly memory and decreasing the time of resolution.

A New Integral Formulation for Eddy Current Computation in Thin Conductive Shells

In order to compute eddy current distributions in thin conductive nonmagnetic shells, a new integral formulation is proposed. The method is based on a surface impedance condition which takes into account the field variation through depth due to skin effect. It is general and enables the modeling of various problems whatever their skin-depth and avoiding the meshing of the air region.