MOTOR-DRIVEN POWER STEERING APPARATUS

摘要

An apparatus for diagnosing the fault of a motor current sensing unit of a motor-driven power steering apparatus. Semiconductor switching devices (hereinafter referred to as devices) (T1 and T4) of an H bridge circuit constituting a motor drive circuit are turned OFF and the devices (T2) is turned ON, and the device (T3) is driven by a PWM signal based on a current command value during fault diagnosis. Simultaneously driving the devices (T3 and T2) makes a current supply to not a motor (M), but a current sensing resistor (R) to measure the current value by a current sensing circuit (C). The measured current value is compared with a predicted current value based on a current command value during a fault diagnosis. When the measured current value is outside the range of the predicted current value, the motor current sensing circuit is judged to be faulty.