ELECTRIC MOTOR DRIVER AND DRIVING CONTROL SYSTEM FOR CONTROLLING DRIVING STATE OF ELECTRIC MOTOR

PURPOSE: An electric motor driver and a driving control system are provided to enhance the stability and the reliability by detecting accurately a phase current and driving smoothly the electric motor in all rotation regions of a low-speed rotation region to a high-speed rotation region. CONSTITUTION: An inverter(2) is used for converting a DC voltage to a three-phase AC voltage. A current detector(11) is used for detecting a current of an inverter busbar to determine each phase current of each phase winding of a three-phase electric motor. An induced voltage estimator(17) is used for estimating an induced voltage of the three-phase electric motor by using the voltage value output of the inverter and the phase current value of the current detector. A rotation position/speed detector(18) is used for estimating a rotation position and a rotation speed of a rotor of the electric motor. A position/speed PI calculator(20,21) is used for calculating rotation position/speed correction values by using a target speed. A PWM signal generator(9) is used for generating a PWM signal for controlling the inverter. A duty correction unit(19) corrects a duty of the PWM signal of the PWM signal generator. The duty correction unit corrects the duty without changing the PWM signal while the current detector detects the current of the inverter busbar.