International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-9 Issue-2, December, 2019 1575 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: B2334129219/2019©BEIESP DOI: 10.35940/ijeat.B2334.129219 Abstract: Regenerative braking has been playing a significant role in electric locomotives to overcome dissipation of the kinetic energy as heat. For high-speed rail topologies, Power electronic transformer based locomotive has the only solution to achieve it. For the isolation purpose and to reduce the weight of the locomotive, a feasible method by substituting loco transformer with a transformer with high frequency design. With the increasing awareness of energy consumption more electrified locomotives now moving to "Green Energy ". This paper aims to describe the importance of hybrid electric locomotive system when compared to conventional one. By integrating the regenerative braking on power electronic transformer with a storage medium will be a promising solution for the future high-speed rails. The simulation of IGBT based dc to dc converter with traction inverter with storage medium has simulated from MATLAB/ SIMULINK platform. Keywords : Line Frequency Transformer (LFT, Power Electronics Transformer (PET), State of Charge(SOC), Variable Voltage Variable Frequency(VVVF), Voltage Source Inverter (VSI) I. INTRODUCTION Regenerative braking technology is a core area for increasing the energy efficiency of the various electric vehicles. Recently most of the system equipped with some energy storage mediums, such as a battery and an ultra-capacitor. Various studies showed that hybrid electric vehicles have achieved their fuel efficiencies by 30-40%, during regenerative braking mode. However, the braking force required by a driver cannot be assured through regenerative braking alone, due to some limitations, such as vehicle speed and battery SOC (state of charge). The braking process of pure electric vehicles is completed by the combination of regenerative braking mode and mechanical braking to overcome friction. History of locomotives originated from the steam propulsion system. After years of research, a wide ------------------------------------------------------------------------------ --- Revised Manuscript Received on December 15, 2019. Sachin Gee Paul *, Research Scholar, Department of Electrical & Electronics Engineering,Sri Ramakrishna Engineering College, Coimbatore,sachingeepaul@gmail.com Dr.CS Ravichandran, Professor,Department of Electrical & Electronics Engineering, Sri Ramakrishna Engineering College,Coimbatore eniyanravi@gmail.com development in the field of internal combustion engine plays a key role in rolling stock technology. Earlier diesel locomotives are widely used for rail transportation , now recent locomotives drives purely based on electric motors but in the case of non-electric locomotives, a prime mover attached to traction motor in which the propulsion of prime mover purely based on the performance of internal combustion engine. The braking system is very essential to reduce or stops the speed of motors for electrical as well as a mechanical system. Various types of braking are applied based on the types of the motors with their operations. The performance behavior of each motor are different from each other, hence these braking methods are divided into three parts mainly, regenerative braking, plugging type braking and dynamic braking. In Regenerative braking when the speed of the motor exceeds the synchronous speed the regenerative mode begins. During this mode, the motor works as a generator and the power is returned back to the grid. When the rotor rotate above the synchronous speed, then the machine runs as generator ,the current and torque reverses thus counter torque act on the axle of the machine thus braking takes place. When the machine run at super-synchronous speed which may create damage mechanical side and electrically also, this issue can overcome by if the variable frequency source is available. Regenerative braking mode can be operated at sub synchronous speed. In many literatures PETs, based technologies were discussed for the performance of electric vehicles. This paper is mainly focusing on the performances of a high-speed locomotive with PET configuration were discussed. The conventional line frequency transformer (LFT) is used commonly in electric locomotives for the isolation and voltage regulation but the major drawback for this LFT is weight [1]. Since due to the low operating frequency, LFTs are bulky and heavy .This LFT is the major weight contributor for a locomotive. Line frequency transformers (LFTs) in railway vehicles are usually enhanced for minimum power density (0.25–0.35 kVA/kg), and efficiency around 94% for 25 kV/50 Hz traction systems. The increase in demand for railway vehicles executes constraints on size, weight, and efficiency of the traction equipment with optimized manner [2]. The better use of new insulation materials, synthetic ester oil as dielectric, design of windings, and coolants may not suitable to fully address the issues. Hybrid Regenerative System on Power Electronic Transformer for Electric Traction Applications Sachin Gee Paul, CS Ravichandran