A Novel Interphase-Bridging Single-Phase Inverter for Photovoltaic and Energy Storage Connected to Railway Traction Power Supply System

The back-to-back railway energy router (BTB-RER) has been a research hotspot in the electrified railways, in order to balance traction network interphase power, reuse braking energy, and access renewable energy sources. However, the existing BTB-RER technologies have been plagued by high system costs. In this paper, a novel railway energy router of Interphase-Bridging single-phase Inverter structure (IBI-RER) is proposed to implement three-port energy transmission in the same way as a traditional BTB-RER based on two back-to-back inverters. Firstly, the power flows among three ports are analyzed in detail and a mathematical model is developed to quantitatively study the strongly coupled power transfer relationship among the three ports: α-phase / β-phase traction buses and the DC bus side. Then, to solve the problem about three-port coupling interactions of both active power and reactive power simultaneously distributed on α-phase and β-phase side, this paper proposes a hybrid power decoupling method based on -added reactive power compensation devices and a power flow optimization algorithm to perform all the same functions as the traditional BTB-RER. Finally, the functional effectiveness and economic superiority of the proposed IBI-RER is verified through comparative experiment results.