Motor drive control device and motor drive control method

A motor drive control device comprising:

• a control circuit configured to output a drive control signal for driving a motor including multiphase coils;
• and
• a drive circuit configured to drive the motor on the basis of the drive control signal output from the control circuit, wherein
• the drive circuit includes:
• an inverter circuit configured to drive the multiphase coils on the basis of the drive control signal;
• and
• a current detection circuit configured to detect a current flowing through the multiphase coils and to output a current detection signal corresponding to the detected current, and
• the control circuit is configured to:
• acquire a drive command signal including a value indicating a target state of an operation of the motor;
• detect, as a peak value, a phase current closest to a q-axis current of a two-phase rotating coordinate system when a d-axis current of the two-phase rotating coordinate system is set to 0 among phase currents flowing through the coils of respective phases and phase currents obtained by inverting the phases of the phase currents flowing through the coils of the respective phases by 180°, on the basis of the current detection signal and a rotation angle of a rotor of the motor, and to calculate the q-axis current when the d-axis current is set to 0, on the basis of an envelope of the peak value;
• and
• generate the drive control signal by performing a vector control computation by using the q-axis current calculated, the drive command signal, a rotation speed of the rotor of the motor, and the rotation angle of the rotor.