The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1998
Filed:
Mar. 27, 1996
Osamu Shinkawa, Suwa, JP;
Akihito Uetake, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A brushless DC motor drive apparatus according to the invention comprises a stator and a rotor, the stator including multi-phase armature windings which are connected in a star formation and generate a plurality of terminal voltages at respective terminals of the armature windings, and the rotor including a plurality of permanent magnets which form pairs of magnetic poles. The motor drive apparatus also includes an inverter coupled to the rotor for adjusting the speed of the rotor, a rotor position detection means for detecting the terminal voltages generated in the armature windings and for generating a position signal indicative of a magnetic pole position of the rotor. The rotor position detection means includes a line voltage generation means for generating line voltages corresponding to the terminal voltages of the armature windings and comparison means for comparing signals derived from the line voltages in predetermined combinations and outputting comparison signals as the positional signal. The motor drive apparatus also includes a drive control means for controlling and driving the inverter according to the position signal generated by the rotor position detection means, the drive control means including PWM (Pulse Width Modulation) chopper control means for generating a PWM chopper control signal to control the inverter. The motor drive apparatus according to the present invention can always detect accurate rotor position without being affected by the rotational frequency or load of the brushless DC motor. Furthermore, the motor drive apparatus can easily expand the operational range of a brushless DC motor, particularly that of a brushless DC motor possessing an embedded magnet-type rotor structure. Additionally, the motor drive apparatus can easily and accurately operate a brushless DC motor according to its motor characteristics and control method.