Models for the AC locomotives regenerative braking

Railway has been playing a significant role in passenger and cargo transportation. Electric railway systems are of growing importance with recent augments on energy saving and environmental friendly. The advantages of electrical railway compared to other transportation systems are cheaper sources of energy, lightweight locomotives, easier maintenance and a lower cost per passenger. Advances in power electronics allow trains to employ regenerative braking, resulting in a safer, more economical means of transport, with reduced maintenance and increased comfort. Estimating the regenerative braking process requires a complex model of the electrical and mechanical components, related to the mechanical behavior of the train, mechanical-electrical conversion in the traction motor operated as a generator, electrical equations of the power distribution system and of the power equipment in the traction substations.