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LABORATOIRE D’ÉLECTROTECHNIQUE ET D’ÉLECTRONIQUE DE PUISSANCE DE LILLE http://l2ep.univ-lille1.fr/ High-Frequency Modeling of Power Converters Supervisors : Arnaud Videt, Nadir Idir [email protected] , office n°115 – P2 University Lille1 [email protected] , office n°117 – P2 University Lille1 Context Power electronics converters are the key power processing devices in applications involving the management of electrical energy. However, because of semiconductor commutations, they generate fast voltage and current transients ( dv/dt and di/dt) that are responsible for conducted electromagnetic emissions. These perturbations include high-frequency common-mode and differential-mode currents spreading to the power supply and polluting the electrical network. Notably, these emissions may exceed the limits imposed by electromagnetic compatibility (EMC) standards, and thereby require bulky and expensive EMC filters. These problems can be reduced if EMC analysis is performed by simulation at the design stage of power converters. For that means, it is necessary to develop high-frequency models of the system devices, especially at the level of the commutation cell (diode-transistor association). Objectives High-frequency simulation of power systems are typically performed in frequency domain, though this approach implies the hypothesis of linear systems which is not valid in case of power electronics converters. Therefore, the accuracy of these methods is limited in frequency validity beyond a few megahertz. On the other hand, frequency-domain simulations are usually fast, which is beneficial in the aim of system optimization including EMC filters design. Thus, this approach is attractive only if the nonlinear effects of power electronics converters are taken into account. The goal of this research topic is to provide frequency-domain models of power converters that are valid up to several tens of megahertz, by improving the modeling methods already developed in the laboratory [1]. The resulting models should provide good accuracy at high frequency with small simulation times compared with conventional models. Experimental bench : power converter, load, and 20-meter-long cable High-frequency spectrum of the current in the ground conductor Work progress The work will be part of ongoing research of the power electronics team. It will take place in the power electronics laboratory, in the P2 building of University Lille 1. The recruited candidate will first have to perform a bibliographic research on high-frequency models of power converters for EMC analysis, with a focus on frequency-domain modeling of the commutation cell. Then, existing laboratory models based on the Multi-Topology Equivalent Sources (MTES) method will be further developed to include the nonlinear effects of the commutations in frequency-domain simulations. The speed and accuracy of numerical simulations will be important criteria. The proposed models will be validated based on experiments on a real DC-DC or DC-AC power converter in the laboratory. Reference [1] « Hybrid Time-Frequency EMI Noise Sources Modeling Method » EPE ’13-ECCE Europe, the 15th European Conference on Power Electronics and Applications, 9-2013 Clément MARLIER, Arnaud VIDET, Nadir IDIR, Houmam MOUSSA, Régis MEURET
