Patent ID: 7852026
Filing Date: 2010-12-14
Classification: H02P

Abstract:
1. A motor drive apparatus comprising: a rotational position estimation device configured to estimate a rotational position of a rotor by detecting a phase voltage generated in a stator coil of a brushless DC motor; a drive control device configured to perform a drive control process of the motor in a first control mode, which is based on the estimated rotational position; a voltage detection device configured to detect a voltage of a power source line; a rotational frequency detection device configured to detect a rotational frequency of the motor; and a control change device configured to change the drive control process in the drive control device to a second control mode so as to perform a forced commutation of the motor based on a rotational frequency detected by the rotational frequency detection device when it is detected by the voltage detection device that overvoltage is applied when the motor is driven.