DESIGN AND SIMULATION OF H-BRIDGE FED ELECTRIC TRACTION DRIVE

Abstract

Act of drawing or state of being drawn, propulsion of vehicle is called the traction and the system of traction involving the use of electricity is called the electric traction system. Electric traction systems are the most widely used because of their qualities like high efficiency, heavy ridership and fast transportation. The introduction of self commuting solid state devices has boosted the application of ac motor drives in electric traction systems. The variable frequency induction motor drives used in AC traction system consist of uncontrolled ac-dc converters and voltage source inverters feeding the induction motor. Such converters induce power quality issues in the power distribution system feeding the traction system such as injecting harmonics which leads to voltage fluctuation, reactive power and low power factor issues. Different international organizations have given guidelines through various standards like IEEE-519, IEC 61000-3-2, etc to inflict limits on the levels of harmonic current emissions. This has lead to novel research in suggesting and developing different ways and means for reducing these harmonic currents and to improve the power quality. Various circuit topologies have been reported in the literature for converter inverter designing for feeding traction motor drive. This work presents the performance analysis of electric traction motor drive consisting of an AC-DC converter fed vector controlled induction motor drive. The converter provides the constant dc link, keeps the input power factor close to unity and also reduces the THD of AC mains current. Modelling and simulated results of the converter fed induction motor drive are presented to demonstrate the features of electric traction drive. The necessary modelling and simulations are done in MATLAB Simulink.