An electric power assist steering control system having an electric motor
actuator and a motor driver circuit for generating and applying a motor
current to the electric motor actuator. A current sensor is included for
measuring the motor current from the motor driver circuit and generating
a feedback signal. A torque sensor is included for sensing an applied
steering torque and providing a torque command signal having a value
indicative of the applied steering torque. A controller calculates a
temperature of the electric temperature of the electric motor actuator by
evaluating the motor current applied to the electric motor actuator. In
the case that the calculated temperature of the electric motor actuator
surpasses a predetermined temperature, the electric power assist steering
control system reduces the amount of motor current applied to the
electric motor actuator thereby reducing the temperature of the electric
motor actuator.