Apparatus to reduce no load current at low frequencies
US5814967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1997 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Aug 13, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P21/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A system for accurately determining a torque current i.sub.qe for use in field oriented control of an induction motor at low rotor frequencies (e.g., about half of the motor rated frequency) which provides an ideal no load current and still enables high torque at low speed. The system includes a frequency/correction angle identifier which, based on an applied stator voltage frequency, provides a correction angle which is added to a perceived phase angle to generate a corrected phase angle which is used to calculate the torque current component i.sub.qe. The torque current component is then used by a slip calculator and an IR compensator to adjust motor operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.