Patent ID: 8154229

Claim:
A control system designed to use a plurality of voltage vectors expressing a switching mode for a switching circuit to thereby control a difference between a current actually flowing in a multiphase rotary machine and a command current value therefore within an allowable range, the plurality of voltage vectors including a zero vector that allows line-to-line voltages in the multiphase rotary machine to be all zero, and a plurality of non-zero vectors that allow at least one of line-to-line voltage in the multiphase rotary machine to be nonzero, the plurality of non-zero vectors defining a plurality of separated regions in a space around a center point at which the difference is zero, the control system comprising a calculating unit configured to calculate a direction of change in the difference during the switching mode for the switching circuit being set to the zero vector; and a zero-vector setting unit configured to set the switching mode for the switching circuit to the zero vector when a preset positional condition between the difference and the direction of change in the difference is met in the space.