The LEI (Laboratoire d’Electronique Industrielle) is one of the laboratories of the DE (Département Electricité) of the EPFL. Its mission and goal are the research and the teaching in the domains of Industrial and Power Electronics. Simulation tools are used both for research and teaching, to allow a good understanding of the structures that are studied before practical tests. This paper will illustrate the way Simplorer is used regarding four main research themes, and regarding pedagogical tools we are developing.