Current sensor and method using differentially generated feedback
US5568047A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 1994 |
| Grant date | Oct 22, 1996 |
| Priority date | — |
| Expiry date | Aug 10, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F38/32
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A current sensor has one signal interface channel including a transformer having a primary winding, a secondary winding and a feedback winding. A magnetic core magnetically couples the primary winding, the secondary winding and the feedback winding. The current sensor further includes a feedback generating circuit responsive to an AC signal in the secondary winding for generating a feedback signal having a continuous polarity supplied to the feedback winding. The feedback signal being effective for maintaining a flux in the magnetic core substantially near zero. The feedback generating circuit is made up of an operational amplifier, such as an amplifier having first and second differential input ports and first and second differential output ports, and a switching assembly designed to generate a compensating AC signal from a DC offset voltage. The compensating AC signal is conveniently coupled to the operational amplifier through the magnetic core.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.