Patent ID: 8716966

Claim:
A rotary electric machine for a vehicle comprising: an armature winding having phase windings of two phases or more; a switching section that includes a bridge circuit having a plurality of upper arms and a plurality of lower arms configured by switching elements to each of which a diode is connected in parallel, in which one end of the switching element of each of the upper arms is connected to a positive terminal side of a battery and one end of the switching element of each of the lower arms is connected to a negative terminal side of the battery via a vehicle body, wherein the switching section rectifies an induced phase voltage of the armature winding; an ON-timing setting section that sets an ON-timing of the switching elements; an OFF-timing setting section that sets an OFF-timing of the switching elements; an energization period detector that detects an energization period in which current flows to the diode connected in parallel to the switching element, when the switching element of each of the lower arms is OFF, the energization period being a period from a time when the phase voltage reaches, from a first threshold value, a second threshold; and a rotation frequency calculator that calculates a rotation frequency based on the energization period detected by the energization period detector, wherein the rotation frequency calculator is configured to calculate the rotation frequency at intervals, and the OFF-timing setting section is configured to set the OFF-timing for the switching elements of each of the upper and lower arms based on the newest rotation frequency calculated by the rotation frequency calculator, the OFF-timing to be set being present of one cycle of the phase voltage.