Motor control unit and vehicle steering system

摘要

When the estimated motor temperature becomes equal to or higher than the first predetermined temperature, an addition angle correction unit temporarily decreases the absolute value of the addition angle output from an addition angle limiter at time intervals. The addition angle correction unit makes the time interval shorter as the estimated motor temperature increases. When the time interval becomes equal to or shorter than the predetermined threshold, that is, when the estimated motor temperature becomes equal to or higher than the second predetermined temperature that is higher than the first predetermined temperature, the addition angle correction unit notifies a command current value changing unit of a current stop command. Thus, the γ-axis command current value is changed to 0, and therefore the steering mode is shifted to the manual steer mode.

主权项

1. A motor control unit that controls a motor and that includes a rotor and a stator that faces the rotor, comprising:
a current drive unit that drives the motor based on an axis current value of a rotating coordinate system that rotates in accordance with a control angle that is a rotational angle used in a control and calculated without receiving an output signal of a rotational angle sensor that detects a rotation angle of the rotor so that the control angle is determined independently from the rotation angle of the rotor; an addition angle calculation unit that calculates, without detecting a change of the rotation angle of the rotor, an addition angle that is to be added to the control angle based on a deviation of a control torque calculated by a control torque calculation unit from a command torque set by a command torque setting unit; a control angle calculation unit that obtains a present value of the control angle by adding the addition angle calculated by the addition angle calculation unit to an immediately preceding value of the control angle in predetermined calculation cycles; a temperature detection/estimation unit having a temperature sensor that detects or estimates a temperature of a heat generation element; and a control angle correction unit that corrects the control angle based on the temperature detected or estimated by the temperature detection/estimation unit, wherein the control angle correction unit includes an addition angle correction unit that intermittently decreases or increases an absolute value of the addition angle that is calculated by the addition angle calculation unit when the temperature detected or estimated by the temperature detection/estimation unit is equal to or higher than a first predetermined value.