To provide a sensorless motor drive control system that will start the sensorless motor quickly and with high reliability, in a control system that rotationally drives the motor by switching, according to the rotation phase of the motor, the current applied to the field coil for each phase of the multi- phase sensorless motor while at the same time performs phase-locked loop (PLL) control of the rotational drive.
When starting the motor, a given phase is made the detecting phase and voltages (Eu, Ev, Ew), which are induced in the detecting phase when current is applied for a short time to a field coil other than in the detecting phase, are detected, from the state of the amplitude of the induced voltage thus detected, the magnetic pole position of the rotor is detected, while at the same time the current carrying phase for starting the motor is determined based on the result of the magnetic pole position detection, and the starting current is applied based on the determination, the magnetic pole position detection and the application of the starting current are performed alternately. Further, errors in the above method are detected accurately and steps are taken quickly and accurately after any occurrence of abnormality.
KAWACHI KUNIHIRO
TSUNODA TOSHIYUKI
KIMURA REIICHI
HITACHI ULSI SYS CO LTD
EASTERN JAPAN SEMICONDUCTOR TE