Harmonic filtering circuit with special transformer
US6856230B2 · kind B2 · utility
Inventor
Key dates
| Filing date | May 27, 2003 |
| Grant date | Feb 15, 2005 |
| Priority date | — |
| Expiry date | Jun 1, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E40/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A filter uses a special autotransformer that has a ferromagnetic core with a plurality of legs and flux return bars. A first coil is located on one leg, and a second coil is located on the same leg, but spaced from the first coil. The first coil and at least part of the second coil are connected in series to receive distorted alternating current and at least that part of the second coil is connected to an output terminal. Between the coils and extending at least part of the way from the first leg to an adjacent leg is a magnetic shunt assembly to divert part of the flux generated in the first coil by the alternating current so that that part does not link with the second coil. An air gap is located to link with the second coil to create an inductor in that coil by flux in the second coil, and a capacitor is connected across the second coil to tune it to the fundamental frequency of the alternating current and substantially reduce harmonics in that current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.