Reduced rating T-connected autotransformer for converting three phase AC voltages to nine/six phase shifted AC voltages
US7375996B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 2006 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | Sep 8, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F30/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention provides a T-connected autotransformer for converting three-phase ac input voltages to nine phase shifted ac voltages feeding three sets of three-phase diode rectifier bridges. The nine phase shifted voltages are at an angle of +20 degree or −20 degree with respect to the supply voltages and their magnitudes are essentially identical. The present design requires substantially fewer coils than other autotransformers for 18-pulse AC-DC converters, resulting in saving in space, volume, weight, size and cost of the converter. The magnetics requirement is only about 30% of the drive rating. The output voltage ratio can also be selected to give an average dc output from the proposed converter same as that of a conventional three-phase diode bridge rectifier. However, it is also possible to step up or step down the output voltage as required.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.