Patent ID: 8258728

Claim:
A control system for controlling a rotary electric machine by switching over a control mode among a sinusoidal wave current control mode, an overmodulation current control mode and a rectangular wave voltage phase control mode, the control system comprising: a stationary switching unit configured to switch over the control mode from the rectangular wave voltage phase control mode to the overmodulation current control mode in a stationary operation condition by using a current phase of a smoothed current produced by filtering high harmonic components of an actual current; and a transitional switching unit configured to switch over the control mode from the rectangular wave voltage phase control mode to the overmodulation current control mode in a transitional operation condition by using a current phase of the actual current; wherein: the stationary switching unit switches over the control mode when the current phase of the smoothed current crosses a stationary switching reference line, which is determined to have a predetermined stationary switching phase difference relative to a current phase of a command current of the rotary electric machine on a d-q plane formed of a d-axis and a q-axis crossing orthogonally; and the transitional switching unit switches over the control mode when a d-axis current value of the actual current crosses a transitional switching reference line, which is determined to have a predetermined switching d-axis current value in a same polarity as a d-axis current value of a command current of the rotary electric machine on the d-q plane.