A method and system of controlling driving of a brushless DC electric motor (BLDC) of an electric water pump are provided. The method includes estimating an initial position of a rotor using a magnitude of a current detected in a three-phase coil wound on a stator and converting a current magnitude that reflects a rotational angle of the rotor with respect to the initial position into two direct currents based on the three-phase current. The converted direct currents are output and a rotational angle, a speed, a flux and a torque of the rotor are acquired based on values of the three-phase current, a voltage generated according to flow of the three-phase current, a predetermined coil resistance, and an inductance input. A speed of the motor is then adjusted based on the acquired rotational angle, speed, flux, and torque of the rotor.
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