Patent ID: 6512341
Filing Date: 2003-01-28
Classification: H02P

Abstract:
A brushless motor driving apparatus for driving a brushless motor which includes a stator having a multiple-phase windings and a rotor having multiple-pole magnets, the apparatus detecting a magnetic pole position of the rotor and switching the winding of the stator to be energized seriatim according to the detected magnetic pole position through an inverter, the apparatus comprising:a DC voltage detector for detecting a DC voltage applied to a main line of the inverter; a terminal voltage detector for detecting a terminal voltage in a non-energizing phase of the windings of the stator; a circulating current period determining section for determining a circulating current period for which a circulating current is flowing according to the DC voltage and the terminal voltage; a memory for storing data of a waveform of the terminal voltage predetermined from characteristics of the brushless motor; and a magnetic pole position detector for identifying the magnetic pole position of the rotor based on the terminal voltage after the end of the circulating current period and the waveform of a terminal voltage predetermined from characteristics of the brushless motor.