POWER CONVERSION SYSTEM

A power conversion system as an aspect of the present invention includes: a power converter using a plurality of legs to convert inputted electric power and output powers in a plurality of phases, each leg including upper and lower arms; and a controller 30 controlling the upper and lower arms of each leg to control pulse current flowing through the leg. The controller 30 calculates a duty ratio instruction of each leg in one control period for each phase and, concerning first and second legs among the plurality of legs provided for a certain one of the phases, changes the phase of the calculated duty ratio instruction so that a time period when positive pulse current flows through the first leg and a time period when negative pulse flows through the second leg overlap each other in the one control period.