CONTROL CIRCUIT OF BRUSH-LESS MOTOR CONTROL CIRCUIT OF SENSOR-LESS BRUSH-LESS MOTOR BRUSH-LESS MOTOR APPARATUS SENSOR-LESS BRUSH-LESS MOTOR APPARATUS AND VACUUM PUMP APPARATUS

摘要

PURPOSE: A control circuit of brush-less motor, a control circuit of sensor-less brush-less motor, a brush-less motor apparatus, a sensor-less brush-less motor and a vacuum pump apparatus are provided to detect the positions of the magnetic poles of the rotor without using sensors even in low speed rotation of 20 rotations per second or lower which has been operated by an open loop conventionally and control to switch voltage vectors applied to the motor windings by a feedback control by using the detected value. CONSTITUTION: A control circuit of a brush-less motor comprises a rotor(6) having magnetic poles, a first winding comprising at least two motor windings for rotating the rotor, a second motor winding comprising at least one motor winding for detecting a position of the rotor, rotor rotating means for rotating the rotor by making a current flow to the first winding, voltage acquiring means for acquiring a voltage induced in the second winding, magnetic pole position acquiring means for acquiring magnetic pole positions of the magnetic poles from the voltage acquired by the voltage acquiring means, and current switching means for switching the current such that a direction of a magnetic field by the first motor winding is changed in accordance with the magnetic pole positions acquired by the magnetic pole position acquiring means.