Patent ID: 6538404
Filing Date: 2003-03-25
Classification: H02M,H02P

Abstract:
A motor apparatus comprising:a DC brushless motor including, a rotor having a plurality of magnetized poles, and a multiple-phase stator coil disposed to supply said rotor with a rotational field during conduction; an inverter circuit for generating voltage to conduct a predetermined coil of said multiple-phase stator coil to form said rotational field; and a comparator for each phase of said multiple-phase stator coil for comparing and detecting induced voltage generated in said stator coil of the phase not conducted as above by rotation of said rotor and a predetermined voltage to obtain a position detection signal for controlling the time to perform said conduction based on said position detection signal, said comparator including, a comparison input device for inputting a first divided voltage to a positive terminal of the comparator for each respective phase, said first divided voltage dividing the voltage of respective ones of said multiple-phase stator coils, and for inputting a second divided voltage to a negative terminal of said comparator, said second divided voltage obtained by dividing the voltage between said first divided voltage of a phase different from the phase input to said positive terminal and an imaginary neutral point voltage obtained by dividing the bus voltage of said inverter circuit, and a position detection device for obtaining said position detection signal by detecting the intersection of the voltage portion based on said induced voltage in said first divided voltage and said second divided voltage by said comparator.