Permanent magnet synchronous motor driving apparatus and driving method for expanding weakening magnetic flux region

摘要

In a driving method of a permanent magnet synchronous motor, which is capable of extending the flux-weakening region of a wide conduction angle drive, the motor is started with a 120o conduction drive in closed loop. The motor drive mode is changed from the 120° conduction drive mode to a 150o conduction drive mode in closed loop, when PWM duty for the 120o conduction drive becomes greater than 95 %, during acceleration. The motor drive is changed from the 150o conduction drive to a forced drive in open loop, during further acceleration, when the PWM duty of the 150o conduction drive becomes greater than 95 %. The motor drive is changed from the forced drive to the 150o conduction drive, when the zero-cross of the back emf is detected again continuously, during deceleration. The motor drive is changed from the 150o conduction drive to the 120o conduction drive during further deceleration.