Drive unit for electric motor

Abstract

A drive unit for driving an electric motor includes two motor drive circuits disposed in parallel and each consisting of a bridge circuit of switching devices each incorporating a reverse blocking diode, a power switch provided between a power supply and each of the bridge circuits, and a function switch provided between the electric motor and each of the bridge circuits. In case of failure of one bridge circuit, the other bridge circuit is used to replace the failed bridge circuit, thereby continuing controlled operation of the electric motor. While these switches which are associated with one of the bridge circuits are closed, the switches associated with the other bridge circuit are kept open. This arrangement prevents the current from flowing from the power supply into the failed bridge circuit. The failed bridge circuit does not allow the electric motor to act as a generator even when any of the switching devices causes an ON fault.

Dependencies are inferred from the claim text.