Universal motor speed controller
US7518324B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 2007 |
| Grant date | Apr 14, 2009 |
| Priority date | — |
| Expiry date | Jan 3, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/145
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Moderately accurate closed loop speed control of a universal motor is attained without the need for any type of speed sensor. Motor armature (across the brushes) voltage is sensed and supplied to a control circuit for processing along with sensed motor current and zero-crossing information. Integration of the motor armature voltage provides a value which is related to current motor speed. By adjusting the gating angle for triac actuation, the armature voltage integral can be maintained at a desired value associated with a desired motor speed. The sensed motor current is also integrated to provide a speed droop compensation value that is added to the desired value, and the gating angle for triac actuation is adjusted to move the armature voltage integral value to approach the summed value of the speed droop compensation value and desired value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.