Absolute position sensing method and apparatus for synchronous elevator machines by detection stator iron saturation
US6401875B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 2001 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Feb 12, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P21/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus of determining the position of a rotor at standstill relative to a stator in a synchronous motor elevator machine includes injecting an AC current having a predetermined single frequency and a predetermined initial phase angle into a stator coil of the stator, and sampling the injected current and resultant voltage a predetermined number of times per period of the frequency. Subsequently the method calculates a stator inductance from the sampled voltages and currents using a DFT. By incrementing the initial phase angel a predetermined number of times over a 360 degree cycle, and repeating the injecting, sampling, and calculating with each incremented phase angle, the algorithm provides a predetermined number of calculated stator inductances. The position of the d axis relative to the stator is then determined from the minimum of the calculated stator inductances.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.