Power Conversion System

A power conversion system comprising:

• a first power converter to perform power conversion between a first AC system and a DC circuit;
• and
• a second power converter to perform power conversion between a second AC system and the DC circuit, wherein
• each of the first power converter and the second power converter includes a plurality of submodules connected in series,
• each of the plurality of submodules includes a plurality of switching elements and a capacitor,
• a current effective value of a capacitor in a first submodule included in the first power converter based on a power factor and an apparent power requested from the first AC system is smaller than a current effective value of a capacitor in a second submodule included in the second power converter based on a power factor and an apparent power requested from the second AC system, and
• a first average voltage value of the capacitor in the first submodule is larger than a second average voltage value of the capacitor in the second submodule,
• wherein the first average voltage value is a value obtained by adding, to the second average voltage value, a difference value between a ripple voltage of the capacitor in the second submodule and a ripple voltage of the capacitor in the first submodule.