SENSORLESS DRIVE CONTROL METHOD AND DRIVE CONTROL SYSTEM OF ELECTRIC MOTOR

摘要

PPROBLEM TO BE SOLVED: To provide a sensorless drive control method of an electric motor which can be surely started by increasing torque at a startup time and which has a simple algorithm, and to provide a control system for implementing the same method. PSOLUTION: The sensorless drive control method includes a step of determining a pole position of a rotor of the electric motor by detecting a current pattern flowing in a winding of each phase by applying a pulse voltage of a high frequency to the winding of each phase of a stator of the motor via two-phase energization, and a step of applying a drive voltage of a low frequency to the winding of each phase of the stator of the motor at specified drive timing by specifying the drive timing of the two-phase energization necessary to rotatably drive the rotor with high torque. Thus, the frequency of the drive voltage is gradually raised while a rotational speed of a rotatably driven rotor of the motor is detected. When the detected rotational speed exceeds a predetermined value, the drive voltage applied to the winding of each phase of the stator is converted into a sine wave, and the motor is rotatably controlled so as to satisfy a desired rotational speed. PCOPYRIGHT: (C)2004,JPO