Method and apparatus for transducerless position and velocity estimation in drives for AC machines
US5565752A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1995 |
| Grant date | Oct 15, 1996 |
| Priority date | — |
| Expiry date | Jun 5, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K15/50
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Power is provided to the stator windings of an AC machine which includes a component at the fundamental drive frequency for the machine and a superimposed signal component which is at a substantially higher frequency than the drive power. The rotor has saliencies which result in a change in impedance as seen at the stator windings to the high frequency excitation signal as a periodic function of rotor rotational position. Such saliencies are inherent in some permanent magnet synchronous and all synchronous reluctance machines, and may be provided by appropriate modification of the rotor of induction machines. The stator response at the signal frequency is then detected to provide a correlation between the response at the signal frequency and the rotor position. The detection of the response at the signal frequency is preferably carried out by a heterodyne detection process, by mixing signals at the signal frequency with the measured stator currents, and filtering the mixed signals to isolate the signal indicative of the rotor position. Conventional squirrel cage induction motors can be provided with sufficient spatial variations in the stator winding impedance as a function of roto…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.