Motor control device

A motor control device of controlling a motor unit that drives a wheel, the motor unit being provided in an electric vehicle, the motor control device comprising:

• a temperature sensor that is associated with a motor coil of the motor unit and is configured to sense a temperature Tc of the motor coil;
• and
• a motor current limiter configured to set a plurality of threshold values of the temperature Tc sensed by the temperature sensor, to set current limiting conditions that are different from each other for respective sectioned temperature ranges defined by the threshold values, and to limit a current for the motor unit according to the current limiting condition for the temperature range to which the temperature Tc having been sensed belongs,
• wherein, if a time difference dTc/dt of a motor coil temperature obtained by differentiating the temperature Tc with respect to a time t indicates a positive value, the motor current limiter allows an allowable upper limit of the time difference dTc/dt of the motor coil temperature to vary depending on the sectioned temperature ranges, and
• the motor current limiter sets, for the respective temperature ranges to one of which the temperature Tc having been sensed belongs, the allowable upper limits of the time difference dTc/dt of the motor coil temperature obtained by differentiating the temperature Tc with respect to the time t so that the allowable upper limit for the temperature range with higher temperature is smaller than the allowable upper limit for the temperature range with lower temperature.