Inverter-motor system with different control characteristics for inverter voltage and frequency
US4317074A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 12, 1979 |
| Grant date | Feb 23, 1982 |
| Priority date | — |
| Expiry date | Sep 12, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P23/28
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An inverter-motor combination is regulated in accordance with this invention to minimize deterioration of the power factor as the inverter is reduced from 100% load. This is accomplished by sensing the motor current and providing a control signal to regulate the inverter output frequency in accordance with a first function, representing virtually linear decrease in frequency as the load is reduced from 100% to substantially 70% of full load. A constant voltage stage is connected to regulate the d-c bus controller to provide a modified control signal for regulating the d-c bus level according to a second function, maintaining the d-c bus voltage at virtually 100% while the load is reduced to 70%. Thus the d-c bridge is not phased back and the power factor of the complete system is not degraded over this described operating range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.