Cécile Labarre

Prediction and measurement of The magnetic near field of a static converter

Increases of switching levels and frequency make the compliance with radiated EMC standards more and more difficult. A modeling method based on the partial equivalent element circuit (PEEC) formulations, permitting to know the field emitted by the layout of complex power electronic structures, is presented in this paper. The near magnetic field of a buck chopper has been measured and calculated. The comparison of the simulated results with measurements shows the effectiveness of the modeling methods and of the near field acquisition bench.

Measurement and Modeling of the Magnetic Near Field Radiated by a Buck Chopper

Static converters are used with increasingly high switching frequencies. Consequently, they impose increasingly severe electromagnetic interference(EMI) constraints in their environment. In order to study and to quantify the radiated perturbations, we have used a test bench for measuring the magnetic field radiated in the near zone. In this paper, we present measurements of the magnetic field radiated by the switching cell of a Buck chopper in the near field at high and low frequencies. By comparing the mappings of the magnetic field over the switching cell with the ones of a circular loop, we have deduced that the switching cell can be effectively modeled by a loop. The loops geometric characteristics and its equivalent current flowing in have been determined from near magnetic field data. The model has been validated at high and low frequencies.

Accurate Modeling of Radiated Electromagnetic Field by a Coil With a Toroidal Ferromagnetic Core

Magnetic components are widely used in power electronics and are the main cause of electromagnetic couplings. Among them, coils with ferromagnetic cores belong to the class of components that are used the most. However the behavior in terms of radiation and coupling to the environment of these components is not widely explored. This paper defines a more accurate model for coils with toroidal ferrite cores in order to get a better understanding of the coupling they created. Then the effects of the winding layout around a toroidal core are first discussed. It is found that the winding topology is the major parameter controlling both the radiated field pattern and its magnitude. A measurement bench has then been developed to validate the hypothesis made. Finally, numerical and analytic models have been elaborated to predict radiated fields from magnetic components.

Hybrid modeling techniques for multilayered printed circuit board in power electronics: association of electromagnetic methods

With the fast development of power electronics circuits at increasing switching frequency (over 10 MHz), the multilayered printed circuits boards (PCBs) are being used more and more in the field of power electronics. In this paper, two main computational methods are presented to simulate the dynamic behavior of power electronics interconnection systems. Our aim is to present a methodology to analyze the electromagnetic (EM) behavior of power PCB regarding parasitic effects ( EM couplings) or dynamic effects (impedance): a general procedure is given to calculate EM couplings between strip conductors in multilayered configurations based on the principle of hybrid methods. Finally, we propose a new method to limit computation time based on matrix sparsification.

Modelling and analysis of the magnetic field radiated by a three phased inverter

In this paper, we analyzed the behavior of a three phased inverter used in speed drives in radiated mode and we modeled it by equivalent diagrams representing electric operation and including parasitic elements. First, we tried to link the amplitude spectra of the radiated magnetic field and the electrical time measurements (currents). Then, under some assumptions, we proposed a modelling of the main differential mode loop with parasitic elements. The model parameters are extracted from measurements and/or technical data of the components (semi-conductors). So, we can determine the dominant resonance frequencies of the structure which are significant in radiated mode.

Interpolation technique in magnetic near field scanning

In this paper, we perform magnetic near field measurements with a test bench. The probe used is sufficiently large to keep a good sensitivity. The measurement step equal to the probe radius lets to have a reasonable measurement time. The spatial step is shortened by a data post-processing technique derive from image restoration domain.

Energy Efficiency of Data Centers: A data-driven model-based approach

Issues in Energy Efficiency of Data Centers (DC) are important, due to the cumulative effects of the increase in the DCs number and in the energy consumption per center. Developing new design recommendations to improve a cooling system efficiency, commonly quantified by the PUE metric (Power Usage Effectiveness) is one objective of the Green IT organizations. For existing DCs, without considering the optimization of the IT workload, a possible way to improve the DCs energy efficiency is to adjust the cooling setpoints. In this paper, a methodology based on predictive models is used to optimize the PUE by improving the cooling setting. The modeling approach consists in exploiting the temperatures and energy measurements at various operating conditions to predict the PUE behavior using data-driven models commonly called black box models. The optimization procedures are based on the simulation of these models in order to estimate the best working conditions.