In-phase power supply device and electrified railway system

The invention provides an in-phase power supply device and an electrified railway system. The in-phase power supply device comprises a three-phase input contact, a first output contact, a second output contact, a phase-shifting transformer module, N converter modules and a control module; the three-phase input contact is used for being connected with a three-phase high-voltage power grid; the first output contact is connected with a first low-voltage power grid; the second output contact is connected with a second low-voltage power grid; the N converter modules are all controlled by the control module; the phase-shifting transformer module is respectively connected with the N converter modules; the output ends of the N converter modules are connected in series and are connected between the first output contact and the second output contact; the control module is used for enabling the three-phase high-voltage power grid to supply energy to the first low-voltage power grid and the second low-voltage power grid;