China’s electrified railway mileage ranks first in the world. As the energy heart of electrified railways, the overall performance of the traction power supply system directly affects the safety, stability, and economic operation of the railway. The through type traction power supply system with a three-phase to single-phase converter as the core device can greatly improve the power quality while also improving energy utilization efficiency. Therefore, this article takes the single-phase inverter on the inverter side of the three-phase to single-phase converter as the research object, and proposes a grid connected control strategy for inverters based on satellite timing, which can achieve consistent output voltage phase for multiple substations and natural and reasonable output for each substation. The control, grid connected circulation, and grid connected strategy of the single-phase inverter were analyzed, and the simulation and experimental results verified the correctness of the theoretical analysis and grid connected strategy.