Application of Field Progammable Gate Arrays in Sophisticated Control Structures of Electric Drive

Abstract

This doctoral thesis deals with the transmission of traction power from the traction vehicle to the train and presents an analysis of the current state of operation of the slip regulator on the III. generation heavy freight locomotive Škoda factory designation 93E. It was necessary to use Field Programmable Gate Array (FPGA) technology to acquire, process and record the data. The introductory part of the thesis is an introduction to the field of the FPGAs and briefly summarizes the history of these integrated circuits. The basic elements of the traction power transmission system are the traction motor, the mechanical system of the traction motor-wheelset and its rotary mass and the wheel-rail contact. From the point of view of the traction motor and its regulator, an analysis of the influence on damping of the mechanical system oscillations by the traction motor and its excitation was performed. The most extensive part of the thesis deals with the motor-wheelset three-mass mechanical system model and its influence on the locomotive's adhesion properties. The model parameters were obtained by analyzing measured speed data of the traction system and the resulting model is compared with other previously published three-mass locomotive traction system models. The last, but most important, element of the traction power transmission system is the wheel-rail contact. This thesis presents currently widely accepted model of the adhesion characteristics on the wheel-rail contact. This model is based on Kalker's linear creep theory and has been further adapted by various authors to better match empirical data. The "zebra" method is described in detail and is utilized to obtain the wheel speed data needed to perform the analysis, including the "autocorrelation" method of data processing. The data obtained were also used to create a mathematical model of traction power transmission from traction machine to the wheelset. Some of the developed measurement methods are generally usable and can be deployed on both current and new locomotives to increase control accuracy. Multiple problems have been identified that cause the suboptimal operation of the slip regulator of the Škoda 93E locomotive and solutions that do not require any mechanical intervention to the design of the current locomotive has been proposed. Some problems that have been identified by studying the model can be generalized to other types of locomotives.