An electric power steering control apparatus can limit a motor impression
voltage thereby to maintain an appropriate motor output even upon
occurrence of a failure of a motor current detection circuit or a motor
current feedback control system. The apparatus includes a motor that
generates an assist force to the steering system, an input processing
section that takes in a steering torque signal from a torque sensor, an
output processing section that drives the motor, and a processing unit
that provides an instruction to the output processing section based on
the steering torque signal. The processing unit includes an impression
voltage calculation section that calculates an amount of operation to the
motor in accordance with the steering torque signal, and an impression
voltage limiting section that limits the impression voltage to
predetermined limit values or less corresponding to the direction of the
steering torque signal.