Sensorless speed detection circuit and method for induction motors
US5654620A · kind A · utility
44Cited by
5References
18Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1995 |
| Grant date | Aug 5, 1997 |
| Priority date | — |
| Expiry date | Mar 9, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a sensorless circuit for detecting rotational speed of a rotor in an induction motor. The circuit includes a switch between the AC source driving the motor and a motor phase winding. When the switch is closed, there is developed across the phase winding a voltage waveform from the AC source. When the switch is subsequently opened, there is developed across the winding a residual voltage waveform induced by the rotor. The speed of the motor is determined by measuring a time interval between selected points on the voltage waveform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.