Modelling and Design of a Current Controller for Light Rail Regenerative Inverter System

Abstract

Three phase voltage source inverter has been proposed to transfer the braking energy of a light rail vehicle back to the utility grid. This solution saves cost in purchasing large number of energy storage modules. However, it raises some concerns on power grid integrity, such as harmonics distortion. Therefore passive filters are normally added to mitigate the harmonics. This paper proposes a grid current controller to minimize the needs of ac filters. The proposed PI controller is stable and shows good dynamic response with the settling time measured at 3.49 ms. In addition, sinusoidal grid currents are produced successfully. The total harmonics distortion index for the grid current is measured at 2.61%.