AC Motor speed control apparatus
US4575667A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1982 |
| Grant date | Mar 11, 1986 |
| Priority date | — |
| Expiry date | Jun 7, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/024
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus for detecting the speed of an AC motor such a synchronous motor or induction motor of the type in which a pulse generator is connected to the shaft of the motor for producing pulses indicative of the motor speed. The motor speed is detected by counting clock pulses whenever the pulses are generated by the pulse generator. Provided are speed computing means responsive to an interrupt pulse of a constant period for estimating the present actual speed of the motor, at times between pulses from the pulse generator, on the basis of the magnitude of a previously commanded armature voltage, magnitude of past and present armature current and a past detected speed, in accordance with the characteristics of the motor. The estimated speed is taken as the detected speed to enable the speed of the motor to be detected with improved accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.