# US 2013/0156116 A1 · Block filter for power line communication

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2013/0156116 A1
- Document ID: US20130156116A1
- Status: Published application
- Kind: A1
- Application number: 13/711,517
- Filed: 2012-12-11
- Published: 2013-06-20
- Earliest claimed: 2011-12-19
- Assignees: Lsis Co., Ltd.
- Inventors: Jae Kang SIM; Young Gyu YU
- Web page: https://patentgrep.com/patent/US20130156116A1

## CPC

- H04B 3/54: Systems for transmission via power distribution lines
- H04B 3/56: Circuits for coupling, blocking, or by-passing of signals
- H04B 2203/5491: using filtering and bypassing
- H04B: TRANSMISSION

## Abstract

Provided is a blocking filter for PLC, the blocking filter including a low pass filter unit including a capacitor and a plurality of inductors, a plurality of magnetic saturation prevention circuits each connected to the inductor in parallel to prevent magnetic saturation of the inductor, and operating in response to an interruption control signal inputted from outside, and a first switch connected or opened in response to the interruption control signal and interconnected between the low pass filter unit and a neutral line.

## Claims

### Claim 1

A blocking filter for PLC, the filter comprising:
a low pass filter unit configured to include a capacitor and a plurality of inductors;
a plurality of magnetic saturation prevention circuits each connected to the inductor in parallel to prevent magnetic saturation of the inductor, and configured to operate in response to an interruption control signal inputted from outside; and
a first switch connected or opened in response to the interruption control signal and interconnected between the low pass filter unit and a neutral line.

### Claim 2 (depends on 1)

The filter of claim 1, wherein the low pass filter unit comprises:
first and second inductors connected to a power line in series; and
a capacitor interconnected between a contact point of the first and second inductors and the first switch.

### Claim 3 (depends on 1)

The filter of claim 1, wherein the first switch is connected when the interruption control signal is turned on and the magnetic saturation prevention circuits operate to prevent the magnetic saturation of the inductors.

### Claim 4 (depends on 1)

The filter of claim 1, wherein the first switch is opened when the interruption control signal is turned off and the magnetic saturation prevention circuits do not operate.

### Claim 5 (depends on 1)

The filter of claim 1, wherein each of the magnetic saturation prevention circuits comprises:
a current transformer so installed as to wrap a periphery of the power line and to detect an input current proportionate to a current flowing in the power line;
a low pass filter configured to filter a frequency signal higher than a predetermined signal in the input current;
a phase correction circuit configured to correct a phase difference of an output signal of the low pass filter; and
an amplification circuit configured to amplify the output signal of the phase correction circuit and to provide the amplified output signal to the inductors.

### Claim 6 (depends on 5)

The filter of claim 5, wherein the magnetic saturation prevention circuits further comprises:
a second switch connected or opened in response to the interruption control signal and interconnected between the low pass filter and the phase correction circuit.

### Claim 7 (depends on 5)

The filter of claim 5, wherein the phase correction circuit corrects a phase difference of the output signal of the low pass filter to allow the output signal to form a phase difference of 180° with the input current detected by the current transformer.

### Claim 8 (depends on 2)

The filter of claim 2, wherein an interruption frequency of the low pass filter unit is determined by sizes of the first and second inductors and capacitor.

### Claim 9 (depends on 2)

The filter of claim 2, wherein each of the first and second inductors has a saturation current having a level lower than that of a rated current of a molded-case circuit breaker.