Patent ID: 8907603
Filing Date: 2014-12-09
Classification: B62D,H02P

Abstract:
1. A steering control apparatus comprising: a direct current power source installed in a vehicle; a three-phase alternating current motor serving as a driving source of an electric power steering apparatus; a motor driving circuit provided between the direct current power source and the three-phase alternating current motor so as to generate a three-phase alternating current from an output of the direct current power source and conduct the generated three-phase alternating current to the three-phase alternating current motor, and the motor driving circuit includes a plurality of drive switching elements; an emergency switching element which is provided in at least two phases of a three-phase power supply line connected to the three-phase alternating current motor within the motor driving circuit, and which is turned off when an abnormality occurs such that the motor driving circuit and the three-phase alternating current motor are disconnected, wherein the emergency switching element is a MOSFET, MOSFETs are provided in pairs in each of the at least two phases of the three-phase power supply line, and parasitic diodes of the pairs of MOSFETs are disposed in opposite orientations to each other; and an emergency turn off control unit programmed to first turn off all of the plurality of the drive switching elements when an abnormality occurs and then sequentially output commands that sequentially turn off the MOSFETs through which a current oriented to turn the parasitic diodes on is flowing when the abnormality occurs, until all of the MOSFETs are turned off.