Motor control apparatus and electric power steering apparatus provided with the same

A motor control apparatus comprising a current detecting circuit to detect a current of a motor as a current detected-value, a drive control unit to drive and control the motor with duty based on a voltage command value determined based on at least a current command value, and a rotation detecting unit to detect an angle and an angular speed of the motor, wherein,

• the motor control apparatus further comprising:
• an adaptive current observer to identify parameter variations of an output model of the motor, to calculate a current estimated-value of the motor and to use the current estimated-value for a calculation of the voltage command value;
• an adaptive identifying diagnosis section to diagnose an estimation error of the current estimated-value outputted from the adaptive current observer;
• and
• a current-detection-impossible state detecting section to detect a current-detection-impossible state that a detection of the current detected-value is impossible;
• wherein the adaptive identifying diagnosis section diagnoses the estimation error of the current estimated-value based on the current estimated-value, the current detected-value, the angle and the current-detection-impossible state and forcibly makes a current-detection-possible state by limiting the duty based on a diagnosis result of the adaptive identifying diagnosis section, and a control of the motor is switched to a current control based on a detected current.