Whitepaper | Electrical Traction Control using PWM and IGBT Technology
In recent years the importance of environmental problems has increased. Because of this electrical traction has replaced the internal combustion engine for mass transit systems. At first DC locomotives were used but they have many drawbacks, such as commutation, sparks on the brushes and difficulty in maintenance. However dc motors have now been replaced by 3-phase squirrel cage induction motors. To allow speed control the dc bus bar is available (+750Vdc) with a digital inverter built into the train. Pulse width modulation (PWM) is commonly used to convert a dc voltage to three symmetrical ac components. Moreover the GTO thyristors is changed to an Insulated Gate Bipolar Transistor (IGBT Technology) for its many advantages. Most metro systems in the world now use this approach. In this paper the mathematical modelling and simulation results are presented and commented on. Introduction The population of big cities needs major projects to solve their transportation problems. The pr...