Motor drive control device, motor unit, and motor drive control method

Abstract

To satisfy a desired air flow-static pressure characteristic while satisfying constraints of a power supply capacity and without over-limiting the drive current. A motor drive control device includes: a control circuit unit configured to generate a drive control signal (Sd) for controlling an actual rotation speed of a motor based on a speed command signal indicating a target rotation speed of the motor; and a motor drive unit configured to drive the motor based on the drive control signal (Sd). The control circuit unit includes a power control unit configured to enable selection of one of: a speed feedback control mode to generate the drive control signal (Sd) so that the actual rotation speed of the motor matches the target rotation speed; and a current feedback control mode to generate the drive control signal (Sd) so that a drive current of the motor matches a target current. The power control unit sets a current threshold corresponding to a power supply voltage (Vdd) supplied from the outside as the target current, and when detecting that the drive current is not less than the current threshold, switches from the speed feedback control mode to the current feedback control mode.