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:
Apr. 26, 1988
Filed:
Sep. 08, 1987
Kanji Takeuchi, Gamagori, JP;
Masami Nagata, Okazaki, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A control apparatus for a brushless dc motor comprises: a parallel connection circuit including a plurality of series circuits connected in parallel; each series circuit having one armature coil and one field-effect transistor, one end of the parallel connection circuit being connected to one end of a dc power source; a free-wheeling diode connected across the parallel connection circuit; first semiconductor switch means connected between the other end of the parallel connection circuit and the other end of the dc power source; a plurality of second semiconductor switch means connected between respective gates of the field-effect transistors; and the one end of the dc power source; a plurality of reverse current blocking elements for preventing reverse currents from flowing into the second semiconductor switch means from the gates of the field-effect transistors; a plurality of comparators for detecting induced voltages developed across the armature coils; a drive circuit responsive to detection output signals from the comparators for sequentially driving the second semiconductor switch means so that the field-effect transistors are turned on and off to sequentially control the energization of the armature coils; and a rotor comprising a permanent magnet having a plurality of magnetic poles which is driven by magnetic fields produced by the sequential energization of the armature coils.