Fail-safe control apparatus for electric vehicle driving motor

Abstract

A PWM generation block implements two-phase/three phase conversion of torque current and exciting current and, on the basis of the converted three-phase torque and exciting currents and a three-phase current for driving and controlling the drive motor, outputs a PWM signal. A torque current estimator receives the same three-phase current as that of the three-phase current input to the PWM generation block, and implement three-phase/two-phase conversion of a three-phase current, by using a phase angle output from the microcomputer to calculate and output estimation values of the torque and exciting currents. A first comparator compares the absolute value of amplitude and the phase angle of the motor primary current and the motor primary frequency which are respectively output from the microcomputer with those which are respectively output from a fail-safe control block. The first comparator outputs a fail-safe signal when it detects differences between the compared values. A second comparator compares the estimation values of the torque and exciting currents which are output from the torque estimator with the torque and exciting currents which are output from the fail-safe control block, respectively. The second comparator outputs a fail-safe signal when it detects differences between the signals compared thereby.