Patent ID: 8513907

Claim:
A power converter for an electric rotating machine comprising: a switching circuit disposed between a power supply and a phase winding of an electric rotating machine, said switching circuit being equipped with switches grouped into an upper arm and a lower arm; and a controller which controls on- and off-operations of the upper and lower arms, said controller controlling the off-operation of one of the upper and lower arms to set a current flywheel duration, in which flywheel current that is current freewheeling from the electric rotating machine is permitted to flow from the electric rotating machine and which is a time length between when phase voltage induced at the phase winding exceeds a first threshold value and when the phase voltage drops below a second threshold value, to a selected time length following the off-operation of the one of the upper and lower arms, wherein said controller turns off the one of the upper and lower arms based on the current flywheel duration.