Abstract: A torque detection portion includes a first arm having a detection coil L1 and a resistor R1, and a second arm having a detection coil L2 and a resistor R2. When a test mode is set, a reference voltage Vref having an abnormal value is outputted to a monitoring portion 13. An abnormal condition is intentionally caused in the monitoring portion 13. A main torque signal Vtm is compared with a sub torque signal Vts in the monitoring portion 13. When the reference voltage Vref set in the monitoring portion 13 has the abnormal value, a sub torque signal Vts having a level of 0 (Vts=0) is forcibly outputted in a normal condition. Then the signal Vtm is equal to the signal Vts, the monitoring portion 13 determines that a shortcircuit occurs between a main torque signal line and a sub torque signal line.

Abstract: A torque detection portion includes a first arm having a detection coil L1 and a resistor R1, and a second arm having a detection coil L2 and a resistor R2. When a test mode is set, a reference voltage Vref having an abnormal value is outputted to a monitoring portion 13. An abnormal condition is intentionally caused in the monitoring portion 13. A main torque signal Vtm is compared with a sub torque signal Vts in the monitoring portion 13. When the reference voltage Vref set in the monitoring portion 13 has the abnormal value, a sub torque signal Vts having a level of 0 (Vts=0) is forcibly outputted inanormal condition. Then the signal Vtm is equal to the signal Vts, the monitoring portion 13 determines that a shortcircuit occurs between a main torque signal line and a sub torque signal line.

Abstract: An object of the present invention is to provide an electric power steering apparatus that can detect failure of a current detector quickly and with less misdetection using torque oscillation from a torque sensor. When the number of times N an absolute value of a differential value of a torque command value Tref exceeds a predetermined threshold value dTq in a predetermined time Tmr has reached a predetermined number Nref it is judged that the current detector has failed.

Abstract: An object of the present invention is to provide an electric power steering apparatus that can detect failure of a current detector quickly and with less misdetection using torque oscillation from a torque sensor. When the number of times N an absolute value of a differential value of a torque command value Tref exceeds a predetermined threshold value dTq in a predetermined time Tmr has reached a predetermined number Nref it is judged that the current detector has failed.