Hybrid filter for reducing distortion in a power system
US5548165A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Jul 18, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E40/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for reducing distortion currents present in an alternating current power system supplying power to a load which includes a passive filter and an active filter. In a first embodiment, the passive filter is operably connected to the power system across the load by a switching device. An active filter is then connected across the switching device and operated to draw a current equal to the current through the passive filter. The active filter and the passive filter are thereby connected in series across the load. The active filter is controlled to draw a fundamental frequency component and to provide distortion currents required by the load. In a second embodiment, the active filter is connected in parallel with a first circuit, the parallel combination of which is connected in series with a second circuit across the load. Besides providing distortion currents required by the load, the active filter is controlled to draw a current substantially in phase with the voltage across it in order to provide damping.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.