Isolated type active emi filter having no additional elements on power line
AssigneeEm Coretech Inc.
InventorsJin Gook KIM, Sang Yeong JEONG, Dong Il SHIN
Life of this patent
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Abstract
Proposed are an electromagnetic interference (EMI) filter for preventing noise emitted from a power line cable, and an isolated type active EMI filter having no additional elements on a power line. The EMI filter includes a common-mode (CM) choke disposed on a power source side, a Y-cap disposed on an EMI source side, and a sensing winding configured to sense a current. The EMI filter also includes an amplifier configured to amplify the noise current, and a transformer configured to inject a signal of the secondary coil into the Y-cap as a compensation signal.
Claims8
A method of reducing electromagnetic interference (EMI) noise using an isolated type active EMI filter,
- wherein the isolated type active EMI filter comprises:
- a sensing winding wound as a coil on a common-mode (CM) choke around which at least two power lines connected to an EMI source are respectively wound;
- an amplifier connected to the sensing winding;
- a transformer connected to the amplifier;
- and
- a Y-cap having opposite ends connected to the at least two power lines and having a secondary winding of the transformer connected between a midpoint of the Y-cap and a ground,
- the method comprising:
- sensing a noise current of the CM choke via the sensing winding;
- amplifying the sensed noise current by the amplifier;
- receiving, by a primary winding of the transformer, a signal amplified by the amplifier;
- and
- transforming, by the secondary winding of the transformer, the amplified signal and injecting the transformed signal to the Y-cap as a compensation signal.
Dependencies are inferred from the claim text.