A Novel Hybrid DC Traction Power Supply System Integrating PV and Reversible Converters

A novel hybrid traction power supply system (HTPSS) integrating PV and reversible converter (RC) is proposed. PV is introduced to reduce the energy cost and increase the reliability of power systems. A reversible converter can achieve multiple objectives including regenerative braking energy recovery, PV energy inverting, DC voltage regulation and power factor improvement. In this paper, the topology and operating modes of the HTPSS are first introduced. Three-level boost converter (TLBC) is employed in the PV system. A double closed-loop control scheme considering both maximum power point tracking (MPPT) and midpoint potential balancing (MPB) is recommended. The reversible converter adopts a multi-modular topology and the independent control for active power and reactive power has been achieved by a current decoupling control. According to the working characteristic of each device, a coordinated control strategy is designed, and four basic principles are given. A system simulation model containing a hybrid traction substation and a train was built, and comprehensive simulations under multi-scenario were carried out. The results show that the reversible converter can accomplish PV energy inversion, DC voltage regulation, regenerative braking energy recovery and power factor improvement, by which a high utilization rate and energy-saving effect can be obtained.