Apparatus for adjusting phase between the different phases in power line communication system

Abstract

Provided is an apparatus for adjusting the phase difference between different phases in a power line communication (PLC) system. The apparatus includes a power signal blocking unit blocking a power signal and allowing a data signal to pass between two different phases on three-phase power lines; and a data signal delaying unit delaying the data signal by the phase difference between the two different phases. Accordingly, it is possible to prevent data collision and a time delay in data transmission between different phases by employing the phase adjusting apparatus in a PLC system, thereby improving the performance of PLC.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

FIG. 1 is a diagram of a power line communication (PLC) system that uses three phases and four power lines;

FIG. 2 is a circuit diagram of an equivalent circuit of the PLC system illustrated in FIG. 1;

FIG. 3 is a diagram illustrating a connection between phases T and S for PLC;

FIG. 4 is a diagram illustrating a connection between the phases T and S illustrated in FIG. 3 via a capacitor;

FIG. 5 is a waveform diagram of signals used for PLC;

FIG. 6 is a diagram illustrating communications established between PLC apparatuses on the same phases in the system illustrated in FIG. 4;

FIG. 7 is a diagram illustrating communications established between PLC apparatuses on different phases in the system illustrated in FIG. 4;

FIG. 8 is a block diagram of a phase adjusting apparatus according to an embodiment of the present invention;

FIG. 9 is a block diagram of a phase adjusting apparatus according to another embodiment of the present invention;

FIG. 10 is a waveform diagram of data signals exchanged between PLC apparatuses on the same phases in a PLC system employing a phase adjusting apparatus according to an embodiment of the present invention; and

FIG. 11 is a waveform diagram of data signals exchanged between PLC apparatuses on different phases in a PLC system employing a phase adjusting apparatus according to an embodiment of the present invention.

Claims

1. A phase adjusting apparatus for use in a power line communication system, comprising: a power signal blocking unit blocking a power signal and allowing a data signal to pass between two different phases on three-phase power lines; anda data signal delaying unit delaying the data signal by the phase difference between the two different phases.

2. The apparatus of claim 1, wherein a frequency of the data signal is higher than a frequency of the power signal.

3. The apparatus of claim 2, wherein the power signal blocking unit comprises a capacitor which has frequency characteristics that block the power signal of low frequency but allow the data signal of high frequency to pass through it.

4. The apparatus of claim 1, wherein the data signal delaying unit comprises: a first signal transmission unit delaying a data signal transmitted from a phase A, which is one of the two different phases, by the phase difference between the phase A and the other phase B, and transmitting the delayed data signal to the phase B; anda second signal transmission unit delaying a data signal transmitted from the phase B by the phase difference between the phases B and A, and transmitting the delayed data signal to the phase A.

5. The apparatus of claim 4, wherein the first signal transmission unit comprises: an isolator blocking the data signal transmitted from the phase B; anda phase delayer delaying the data signal transmitted from the phase A by the phase difference between the phases A and B.

6. The apparatus of claim 5, wherein the phase delayer delays the data signal for a fixed amount of time at all of frequencies available.

7. The apparatus of claim 6, wherein the phase delayer comprises a Bessel type filter.