Digital motor controller for color wheel
US5625424A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1994 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Nov 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A digital motor controller (17) for controlling both the phase and speed of a brushless DC motor (16). An error detection unit (21) detects a speed error or a phase error. An error logic unit (22) uses the error to determine a speed control value, that is proportional to represent an average motor input voltage that varies from the current input voltage by an amount determined by the error. A pulse width modulation unit (23) receives the speed control value and uses it to determine the duty cycle for the motor drive signals. A commutation unit (24) modulates the appropriate drive signal, and a drive stage (27) delivers the drive signals to the motor (16).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.