Analysis, modelling and optimization of a control algorithm for two stages of a power electronic converter implemented on a subway rolling stock

With the recent progresses in modeling environments, the study and the simulation of electronic components that constitute electric traction have become increasingly simple and intuitive. This working approach has been introduced over the years in the field of railway traction where the management of high power levels and the need for a much greater reliability than small applications are involved. This type of study therefore allows on the one hand to reduce the costs of software development related to the expensive, in terms of time and costs, field tests. On the other hand it permits to study the system in a more detailed way in order to intervene more precisely both in implementation and maintenance. This document will focus on two main component of a railway traction converter, the line chopper and the braking chopper. The first one is necessary for voltage regulation and filtering for the supply of the induction motors’ inverter. The second one is needed for the regulation of the voltage upstream and downstream of the line chopper and for the management of excess energy present on the dc-link capacitor, the storage element placed at the inverter’s ends. The purpose of the presented work is to obtain, starting from a pre-existing code, the optimized control logics for the management of the systems described above. Moreover it aims to create accurate models of the electronic components capable of faithfully simulating real behavior and interfacing with the obtained control. In conclusion, simulation results, the improvements achieved and the final considerations will be pointed out. The thesis work was conducted at IKOS Consulting Italia as part of a project with the aim of generating the software for a traction converter to be implemented on a subway train.