Motor controller

In an electric motor control apparatus for a multiphase AC electric motor, including motor rotational angle detection means for calculating a rotational angle of the electric motor, a current detection circuit which calculates currents flowing through respective phases of the electric motor, current control means for determining multiphase voltage commands in accordance with a target q-axial current corresponding to a target value of a torque to be generated by the electric motor, and the detection currents of respective phases and the motor rotational angle from the current detection circuit and the motor rotational angle detection means, a switching-element drive circuit which subjects the multiphase voltage commands from the current control means, to PWM modulation, and which gives commands of switching operations to an inverter, and the inverter which receives switching operation signals from the switching-element drive circuit, and which applies voltages to the respective phases of the electric motor and causes currents to flow therethrough;

• an electric motor control apparatus wherein the current control means comprises normal-mode current control means for use in a normal mode, abnormal-mode current control means for use in an abnormal mode, abnormality decision means for detecting an abnormal state of the electric motor or the inverter, and changeover means for selecting either the normal-mode current control means or the abnormal-mode current control means on the basis of a command from the abnormality decision means, wherein in case of occurring abnormality to one phase of the electric motor or the inverter, the abnormal-mode current control means is selected by the changeover means, and abnormal-mode multiphase voltage commands generated by the abnormal-mode current control means are set as the multiphase voltage commands for the switching-element drive circuit.