Control apparatus for brushless dc motors
US4740734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1987 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Sep 8, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/28
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
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 ene…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.