Motor control device, electromechanical integrated unit, hybrid system, electric power steering system, and motor control method

A motor control device that controls driving of an AC motor that is connected to a power transformer that performs power transform from DC power to AC power and outputs a rotational driving force generated by driving using the AC power via a speed reducer, the motor control device comprising:

• a carrier generator that generates a carrier wave;
• a carrier frequency adjuster that adjusts a frequency of the carrier wave;
• and
• a gate signal generator that performs pulse width modulation on a voltage command according to a torque command using the carrier wave and generates a gate signal for controlling an operation of the power transformer,
• wherein the carrier frequency adjuster changes a phase difference between the voltage command and the carrier wave based on the torque command and a rotational speed of the AC motor, and adjusts the frequency of the carrier wave such that a difference between a meshing frequency of the speed reducer and a harmonic component of a fundamental harmonic current according to the voltage command falls within a predetermined range.