Sensorless commutation position detection for brushless motors
US5600218A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1995 |
| Grant date | Feb 4, 1997 |
| Priority date | — |
| Expiry date | Sep 11, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for the sensorless determination of commutation position in a brushless motor. The electric current flowing within the active, or energized, stator coil during energization is differentiated to produce a current rate of change waveform. The current rate of change waveform is compared to a predetermined voltage threshold which is set to approximate the point at which the rotor is in direct positional alignment with the active stator. From this comparison, it is determined when the current rate of change waveform fails to intersect the predetermined voltage threshold. This information may be used to commutate the application of a driving signal to the next stator coil in succession to maintain continuous torque on the rotor. This information may also be indicative of a stalled condition, in which case a stall indicator is triggered to alert the user of the stalled condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.