EMC in power electronics - Disturbance reduction, simulation

This article describes the principles involved in reducing electromagnetic disturbance in static converters, and introduces simulation methods. T aking EMC into account in the design of a static converter has become a more or less well-established reality. It requires the designer to be multi-disciplined, both in the field of static conversion (knowledge of techniques for increasing efficiency, static and dynamic performance, compactness) and in the field of EMC (knowledge of phenomena, optimization of waveforms, minimization of coupling, compliance with standards, electromagnetic susceptibility), as well as the metrology (high frequency and high current) associated with these fields.

Simulation tools are currently only partially able to deal with the EMC of static converters. The software used is of the "circuit" type for conducted disturbances and specific for radiated disturbances. An emerging trend is the appearance of software for calculating parasitic wiring elements or radiated phenomena. However, if they are to become genuine CAD (Computer-Aided Design) tools, such software still suffers from limitations in terms of available models, functionalities and calculation times. Last but not least, they are not yet fully integrated, as is the case for low-current electronics CAD. However, with rapid improvements and increasing computing power, power electronics CAD software integrating all EMC aspects will soon be a reality.

After having explained the phenomena of disturbance generation and transmission in static converters in the article EMC: sources of disturbance, couplings, SEM [34] , this article sets out, in the first part, some principles for reducing electromagnetic disturbances, by acting at source or on couplings. The second part is devoted to methods for simulating conducted and radiated disturbances; the principles involved in building models of active and passive components and cabling are discussed, and the main simulation techniques are outlined.