CONTROLLER FOR MOTOR DRIVE CONTROL SYSTEM AND VEHICLE INSTALLED WITH THE SAME

PROBLEM TO BE SOLVED: To provide a motor drive control system capable of suppressing electrical current fluctuations generated due to a switching delay of a control mode when switching from square-wave control to PWM control.SOLUTION: An ECU 300 for controlling a motor drive control system 100 drives an AC motor 200 by controlling an inverter 140 by either a square-wave control mode or a PWM control mode. The ECU 300 comprises: a control mode selecting section 330; and an A/D conversion section 340 that A-D converts a motor current of the AC motor 200. The A-D conversion section 340 operates according to a faster execution cycle than an execution cycle based on an electrical angle of the AC motor 200 when a rotational speed of the AC motor 200 sharply drops in the square-wave mode. The control mode selecting section 330 switches from the square-wave control mode to the PWM control mode according to occurrence of electrical current fluctuations of the motor current in the square-wave control mode.