CONTROLLER OF SENSORLESS THREE-PHASE BRUSHLESS MOTOR AND VACUUM PUMP

摘要

PROBLEM TO BE SOLVED: To provide a controller of a sensorless three-phase brushless motor in which a rotor can be initially rotated reliably in a predetermined rotational direction.SOLUTION: A controller 10 of a sensorless three-phase brushless motor includes a control unit 102 for conducting a current to two phases of a three-phase stator coil excepting one idle phase, a storage unit 102a prestoring the correlation of the time change characteristics of induction voltage generated in the idling phase when conduction is performed by the control unit 102 and the commutation start timing after conduction, induction voltage characteristics detection units (103-105) for detecting the time change characteristics of induction voltage by measuring the induction voltage generated in the idling phase during conduction, and a control unit 102 as a determination unit for determining the commutation start timing after conduction, on the basis of the time change characteristics detected and the correlation stored in the storage unit 102a.