Reverse phase angle control of A.C. power loads
US5072170A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 1990 |
| Grant date | Dec 10, 1991 |
| Priority date | — |
| Expiry date | Aug 6, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
AC power loads such as from transformers, motors, high in-rush heaters, air conditioners, etc., are controlled by the use of bipolar transistors, FET transistors, gate turn-off SCRs and IGBT to turn on the load at zero-cross over and to turn off the load at any point in the sine wave which produces the desired amount of power. This reduces RFI and virtually eliminates di/dt at turn on since both voltage and current start at the same zero cross-over, and hence will improve the power factor. Both analogue and digital logic systems can also be utilized to produce this type of phase control, and a wide variety of possibilities are available such as serial and parallel input, the use of full wave bridge control, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.