A multigroup, multiphase driving system includes a power converter that converts direct current power into alternating current power and vice versa, a direct current power supply connected to a direct current side of the power converter to be charged with and discharge direct current power, and a rotary electric machine connected to an alternating current side of the power converter and including a plurality of groups of multiphase armature windings, and further including a determination unit that determines the number of groups to be used to drive the rotary electric machine on the basis of a rotation speed of the rotary electric machine, a current flowing through the rotary electric machine, a direct current power supply voltage of the direct current power supply, and a carrier frequency of the power converter, the multigroup, multiphase driving system overall loss in the system can be reduced.