Torque ripple suppression control device for permanent magnet motor and electric power steering system

A torque ripple suppression control device for a permanent magnet motor, comprising:

• a current command conversion unit that outputs a current command value based upon a torque command value input thereto from an external source;
• a position detector that outputs a position detection value by detecting a rotational position of the permanent magnet motor;
• a current detection unit that outputs a current detection value by detecting a current at the permanent magnet motor;
• an induced voltage coefficient setting unit that outputs, based upon the position detection value, an information signal related to an induced voltage coefficient for an induced voltage at the permanent magnet motor;
• a torque ripple suppression operation unit that outputs, based upon the information signal and a preset proportional gain, a current correction command value for the permanent magnet motor;
• a current control operation unit that outputs, based upon addition results obtained by adding together the current command value and the current correction command value and the current detection value, a voltage command value based upon which the permanent magnet motor is to be driven;
• and
• a power converter that outputs, based upon the voltage command value, a voltage with which the permanent magnet motor is to be driven.