Integrated Configuration and Control Strategy for PV Generation in Railway Traction Power Supply Systems

Recently, electric railways have experienced a rapid development causing an increasing power demand. Due to the flexible installation available at trackside land along railways, photovoltaic (PV) generation is suggested as an extension to the traction power supply system (TPSS) in railways. First, this paper proposes a three-phase integrated configuration for PV generation connected to a two-phase traction network and the on-site consumption of solar resources alongside railways. In this configuration, another inverse V/V transformer is used to maintain a balanced three-phase low voltage (LV) AC bus from a two-phase traction network. It is more convenient for accessing PV generation units. Then, in order to mitigate the negative sequence currents caused by electric trains, an individual phase current (IPC) control strategy for PV converters is developed for power quality improvement. It can not only supply the locomotive with asymmetrical currents, but also provide feedback to the grid through symmetrical currents. All the implementation and calculations are conducted in the three-phase stationary reference frame without any sequence extracting and power compensations. Finally, simulation results are presented to validate the effectiveness of the proposed IPC control strategy.