CN111490809A - Isolation circuit applied to power line carrier test system - Google Patents
Isolation circuit applied to power line carrier test system Download PDFInfo
- Publication number
- CN111490809A CN111490809A CN202010431386.7A CN202010431386A CN111490809A CN 111490809 A CN111490809 A CN 111490809A CN 202010431386 A CN202010431386 A CN 202010431386A CN 111490809 A CN111490809 A CN 111490809A
- Authority
- CN
- China
- Prior art keywords
- line
- inductance
- branch
- junction
- filtering branch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002955 isolation Methods 0.000 title claims abstract description 53
- 238000012360 testing method Methods 0.000 title claims abstract description 47
- 238000001914 filtration Methods 0.000 claims abstract description 172
- 239000003990 capacitor Substances 0.000 claims description 22
- 238000010586 diagram Methods 0.000 description 12
- 230000001939 inductive effect Effects 0.000 description 10
- 238000004891 communication Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- WJZHMLNIAZSFDO-UHFFFAOYSA-N manganese zinc Chemical compound [Mn].[Zn] WJZHMLNIAZSFDO-UHFFFAOYSA-N 0.000 description 3
- QELJHCBNGDEXLD-UHFFFAOYSA-N nickel zinc Chemical compound [Ni].[Zn] QELJHCBNGDEXLD-UHFFFAOYSA-N 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/30—Reducing interference caused by unbalance current in a normally balanced line
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
- H04B3/56—Circuits for coupling, blocking, or by-passing of signals
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Filters And Equalizers (AREA)
Abstract
The invention discloses an isolation circuit applied to a power line carrier test system, which relates to the technical field of power line carrier equipment test and comprises an inductance filtering branch, a rated input impedance branch and a rated output impedance branch, wherein the inductance filtering branch consists of L-line inductance filtering branches and N-line inductance filtering branches with the same structure, the rated input impedance branch is connected between the input end of the L-line inductance filtering branch and the input end of the N-line inductance filtering branch, the rated output impedance branch is connected between the output end of the L-line inductance filtering branch and the output end of the N-line inductance filtering branch, and the isolation of 100 KHz-12 MHz carrier frequency bands is realized through the inductance filtering branch, the rated input impedance branch, the rated output impedance branch and the like.
Description
Technical Field
The invention relates to the technical field of power line carrier equipment testing, in particular to an isolation circuit applied to a power line carrier testing system.
Background
The closest prior patents: CN105071835A, a wideband carrier communication attenuation circuit and coupling circuit.
The power line carrier communication refers to a communication method for transmitting data by means of a power line. The carrier test system is a platform for providing a test environment and a case for power line carrier communication equipment, and the carrier test platform in practical application faces two problems:
two or more carrier test systems interfere with each other.
Power line noise interferes, which is within the carrier band.
The interference in the carrier frequency band enters the carrier test system to affect the test result of the carrier module.
In order to ensure that the carrier test system is not interfered, an isolation device is needed to isolate other carrier signals or high-frequency interference signals. The isolator is a device for deeply attenuating an input high-frequency signal, can attenuate the high-frequency signal very little, and is applied more and more widely along with the development of the technology and the requirement of an electromagnetic compatibility test. At present, the power line carrier isolation equipment is less, and the following defects also exist:
the isolator is based on weak current design and cannot be used in power line carrier.
In order to meet the isolation requirement, the isolator is limited by the parameters of the existing device, can only allow a small-current 220V power line to pass, cannot supply power for the carrier test platform, and therefore is limited in use.
In a carrier test system, an isolator is required to have certain impedance, the carrier test result is influenced when the impedance is too small, and the isolation capability is reduced when the impedance is too large. The existing high-current isolator has the problem of low impedance, so that the test result is inaccurate; meanwhile, the isolator is large in size and inconvenient to use.
Problems with the prior art and considerations:
how to solve the technical problem of the isolation unit suitable for the carrier frequency range of 100 KHz-12 MHz.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an isolation circuit applied to a power line carrier test system, which realizes the isolation of a carrier frequency band of 100 KHz-12 MHz through an inductance filtering branch circuit, a rated input impedance branch circuit, a rated output impedance branch circuit and the like.
In order to solve the technical problem, the technical scheme includes that the isolation circuit applied to the power line carrier test system comprises an inductance filtering branch, a rated input impedance branch and a rated output impedance branch, wherein the inductance filtering branch comprises an inductance filtering branch of L lines and an inductance filtering branch of an N line, the inductance filtering branch is identical in structure, the rated input impedance branch is connected between the input end of the inductance filtering branch of L lines and the input end of the inductance filtering branch of the N line, and the rated output impedance branch is connected between the output end of the inductance filtering branch of L lines and the output end of the inductance filtering branch of the N line.
The technical scheme includes that an inductance filtering branch of the L line is a first inductance L0L of L line, an inductance filtering branch of the N line is a first inductance L2N 1 of the N line, a rated input impedance branch is formed by connecting a first resistance R1 and a first capacitance C1, a rated output impedance branch is formed by connecting a third resistance R3 and a third capacitance C3, a junction 1 of a first inductance 3 of a 3 line is an input end of the inductance filtering branch of the 3 line, a junction 2 of a first inductance 3 of the 3 line is an output end of the inductance filtering branch of the 3 line, a junction 1 of the first inductance 3N 3 of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of the first inductance 3N 3 of the N3 line is an output end of the inductance filtering branch of the N line, a junction 1 of the first inductance filtering branch of the first inductance 3 line of the 3 line, a first resistance R3, a first inductance filtering branch of the N3 line, a junction 2 of the first inductance filtering branch of the N3 line and a junction of the first inductance filtering branch of the N3 line are sequentially connected with the third inductance filtering branch of the third inductance filtering line 3, and the junction of the inductance filtering line 3.
The technical scheme is that the inductance filtering branch of the line comprises a first inductance 0 21 and a second inductance 12 of the line, the inductance filtering branch of the line comprises a first inductance 3N and a second inductance 5N of the line, the rated input impedance branch is a first capacitance C, the rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a joint 2 of a first inductance 41 of the line 6 is connected with a joint 1 of a second inductance 8 of the line 7, a joint 1 of a first inductance 1 of the line 0 is an input end of the inductance filtering branch of the line 2, a joint 2 of a second inductance 12 of the line 3 is an output end of the inductance filtering branch of the line 5, a joint 2 of a first inductance N of the line N is connected with a joint 1 of a second inductance N of the line N, a joint 1 of the first inductance N of the line N is an input end of the inductance filtering branch of the line N, a joint 2 of the second inductance N of the line N is an output end of the inductance filtering branch of the line N, a joint 1 of the first inductance filtering branch of the line 41 of the line L, a joint 1 of the first inductance of the line, a joint of the second inductance filtering branch of the line N, a joint 2 of the second inductance filtering branch of the line and a joint of the second inductance filtering branch of the line L2 of the inductor of the line are sequentially connected.
The technical scheme is that the filter circuit further comprises a capacitance filtering branch which is a second capacitance C2, and the second capacitance C2 is connected between the connection position of a first inductance LL 1 of the L line and a second inductance LL 2 of the L line and the connection position of a first inductance L N1 of the N line and a second inductance L N2 of the N line.
The technical scheme is that the inductance filtering branch of the wire comprises a first inductance 0 21 and a second inductance 12 of the wire, the inductance filtering branch of the N wire comprises a first inductance 3N and a second inductance 5N of the N wire, a rated input impedance branch is formed by connecting a first resistance R and a first capacitance C, a rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a joint 2 of a first inductance 41 of the 6 wire is connected with a joint 1 of a second inductance 8 92 of the 7 wire, a joint 1 of the first inductance 1 of the 0 wire is an input end of the inductance filtering branch of the 2 wire, a joint 2 of the second inductance 12 of the 3 wire is an output end of the inductance filtering branch of the 5 wire, a joint 2 of the first inductance N of the N wire is connected with a joint 1 of a second inductance N of the N wire, a joint 1 of the first inductance filtering branch of the N wire is an input end of the inductance filtering branch of the N wire, a joint 2 of the second inductance N of the N wire is an output end of the inductance filtering branch of the N wire, a first inductance N joint 2 of the filtering branch of the N wire is sequentially connected with a joint of the first inductance C1 of the second inductance filtering branch of the N wire, a joint of the inductance of the N wire, a first inductance filtering branch of the N wire is sequentially connected with a joint 2 of the third inductance C2 of the third.
The technical scheme is that the filter circuit further comprises a capacitance filtering branch which is a second capacitance C2, and the second capacitance C2 is connected between the connection position of a first inductance LL 1 of the L line and a second inductance LL 2 of the L line and the connection position of a first inductance L N1 of the N line and a second inductance L N2 of the N line.
The further technical scheme is as follows: the first resistor R1 is a resistor with a value range of 0 ohm to 50 ohm, and the first resistor R1 is a chip resistor.
The further technical scheme is as follows: the first resistor R1 is a 0 ohm resistor.
The further technical scheme is as follows: the third resistor R3 is a resistor with a value range of 25-50 ohms, and the third resistor R3 is a chip resistor.
The further technical scheme is as follows: the rated input impedance branch comprises a first resistor R1 and a first capacitor C1, and the first resistor R1 is connected with the first capacitor C1.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:
an isolation circuit applied to a power line carrier test system comprises an inductance filtering branch circuit, a rated input impedance branch circuit and a rated output impedance branch circuit, wherein the inductance filtering branch circuit consists of L-line inductance filtering branch circuits with the same structure and an N-line inductance filtering branch circuit, the rated input impedance branch circuit is connected between the input end of the L-line inductance filtering branch circuit and the input end of the N-line inductance filtering branch circuit, the rated output impedance branch circuit is connected between the output end of the L-line inductance filtering branch circuit and the output end of the N-line inductance filtering branch circuit, and the isolation of 100 KHz-12 MHz carrier frequency bands is realized through the inductance filtering branch circuit, the rated input impedance branch circuit, the rated output impedance branch circuit and the like.
See detailed description of the preferred embodiments.
Drawings
Fig. 1 is a circuit schematic diagram of embodiment 1 of the present invention;
fig. 2 is a circuit schematic diagram of embodiment 2 of the present invention;
fig. 3 is a circuit schematic diagram of embodiment 3 of the present invention;
FIG. 4 is a schematic diagram of an equivalent circuit of the power line of 220V/50Hz in the embodiments 2 and 3;
FIG. 5 is a schematic circuit diagram of the embodiment 2 for accessing a 220V/50Hz power line;
FIG. 6 is a schematic circuit diagram of an embodiment 3 for accessing a 220V/50Hz power line;
FIG. 7 is a simulation diagram of amplitude-frequency characteristics in example 2;
FIG. 8 is a simulation diagram of amplitude-frequency characteristics in example 3;
FIG. 9 is a 220V/50Hz industrial frequency input/output simulation diagram of examples 2 and 3.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and it will be apparent to those of ordinary skill in the art that the present application is not limited to the specific embodiments disclosed below.
Example 1:
as shown in fig. 1, the isolation circuit applied to a power line carrier test system includes an inductive filtering branch, a rated input impedance branch, a rated output impedance branch and a capacitive filtering branch, where the inductive filtering branch includes an inductive filtering branch of L lines and an inductive filtering branch of N lines with the same structure, the rated input impedance branch is connected between an input end of the inductive filtering branch of L lines and an input end of the inductive filtering branch of N lines, and the rated output impedance branch is connected between an output end of the inductive filtering branch of L lines and an output end of the inductive filtering branch of N lines.
The inductance filtering branch of the L line comprises first to X inductors L to L1X of an L line, the inductance filtering branch of the N line comprises first to X inductors L N1 to 1 NX of the N line, the rated input impedance branch comprises a first resistor R1 and a first capacitor C1 which are connected, the rated output impedance branch comprises an X +1 resistor RX +1 and an X +1 capacitor CX +1 which are connected, first to X inductors 1 31 to 1X of the 1 line are sequentially connected in sequence, a junction 1 of the first inductor 1N 1 of the 1 line is an input end of the inductance filtering branch of the 11 line, a junction 2 of the X inductor 1X 0X of the 12 line is an output end of the inductance filtering branch of the 1 line, first to X inductor 1N + N X72N X3N 1N X N X N X N X N X N X N X N X.
The capacitance filtering branch comprises X-1 capacitors, namely second to X-th capacitors C2 to CX with the same structure, and the second capacitor C2 is connected between the connection position of a first inductor LL 1 of a L line and a second inductor LL 2 of a L line and the connection position of a first inductor L N1 of an N line and a second inductor L N2 of the N line.
Example 2:
as shown in fig. 2, the isolation circuit applied to the power line carrier test system disclosed by the invention comprises an inductance filtering branch, a rated input impedance branch, a rated output impedance branch and a capacitance filtering branch, wherein the inductance filtering branch comprises L-line inductance filtering branches and N-line inductance filtering branches with the same structure, the rated input impedance branch is connected between the input end of the L-line inductance filtering branch and the input end of the N-line inductance filtering branch, and the rated output impedance branch is connected between the output end of the L-line inductance filtering branch and the output end of the N-line inductance filtering branch.
The inductance filtering branch of the line comprises a first inductance 0 21 and a second inductance 12 of the line, the inductance filtering branch of the N line comprises a first inductance 3N and a second inductance 5N of the N line, the rated input impedance branch is a first capacitance C, the rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a junction 2 of a first inductance 41 of the 6 line is connected with a junction 1 of a second inductance 8 of the 7 line, a junction 1 of the first inductance 1 of the 0 line is an input end of the inductance filtering branch of the 2 line, a junction 2 of a second inductance 12 of the 3 line is an output end of the inductance filtering branch of the 5 line, a junction 2 of the first inductance N of the N line is connected with a junction 1 of a second inductance N of the N line, a junction 1 of the first inductance N of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of the second inductance N of the N line is an output end of the inductance filtering branch of the N line, a junction 1 of the first inductance 41 of the L line, the first capacitance C and the first inductance of the N line are sequentially connected with a junction 2 of the second inductance filtering branch of the L line, a junction 2 of the second inductance of the L line and the third inductance C2 of the N line.
The capacitance filtering branch is a second capacitance C2, and the second capacitance C2 is connected between the connection of the first inductance LL 1 of L line and the second inductance LL 2 of L line and the connection of the first inductance L N1 of N line and the second inductance L N2 of N line.
Example 3:
as shown in fig. 3, the isolation circuit applied to the power line carrier test system disclosed by the invention comprises an inductance filtering branch, a rated input impedance branch, a rated output impedance branch and a capacitance filtering branch, wherein the inductance filtering branch comprises L-line inductance filtering branches and N-line inductance filtering branches with the same structure, the rated input impedance branch is connected between the input end of the L-line inductance filtering branch and the input end of the N-line inductance filtering branch, and the rated output impedance branch is connected between the output end of the L-line inductance filtering branch and the output end of the N-line inductance filtering branch.
The inductance filtering branch of the line comprises a first inductance 0 and a second inductance 12 of the line, the inductance filtering branch of the N line comprises a first inductance 3N and a second inductance 5N of the N line, the rated input impedance branch is formed by connecting a first resistance R and a first capacitance C, the rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a junction 2 of a first inductance 41 of the 6 line is connected with a junction 1 of a second inductance 8 92 of the 7 line, a junction 1 of a first inductance 1 of the 0 line is an input end of the inductance filtering branch of the 2 line, a junction 2 of a second inductance 12 of the 3 line is an output end of the inductance filtering branch of the 5 line, a junction 2 of the first inductance N of the N line is connected with a junction 1 of a second inductance N of the N line, a junction 1 of the first inductance N of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of the second inductance filtering branch of the N line is an output end of the inductance filtering branch of the N line, a first inductance 41 of the L line, a junction 1 of the first inductance N of the N line, a junction 2 of the second inductance filtering branch of the N line, a junction of the third inductance filtering branch of the N and a junction of the third inductance C2 of the N.
The capacitance filtering branch is a second capacitance C2, and the second capacitance C2 is connected between the connection of the first inductance LL 1 of L line and the second inductance LL 2 of L line and the connection of the first inductance L N1 of N line and the second inductance L N2 of N line.
Example 4:
the invention discloses an isolation circuit applied to a power line carrier test system, which comprises an inductance filtering branch, a rated input impedance branch and a rated output impedance branch, wherein the inductance filtering branch consists of L-line inductance filtering branches with the same structure and an N-line inductance filtering branch, the rated input impedance branch is connected between the input end of the L-line inductance filtering branch and the input end of the N-line inductance filtering branch, and the rated output impedance branch is connected between the output end of the L-line inductance filtering branch and the output end of the N-line inductance filtering branch.
An inductance filtering branch of the L line is a first inductance L0L of L line, an inductance filtering branch of the N line is a first inductance L2N 1 of the N line, the rated input impedance branch is formed by connecting a first resistance R1 and a first capacitance C1, the rated output impedance branch is formed by connecting a third resistance R3 and a third capacitance C3, a junction 1 of a first inductance 3 of the 3 line is an input end of the inductance filtering branch of the 3 line, a junction 2 of a first inductance 3 of the 3 line is an output end of the inductance filtering branch of the 3 line, a junction 1 of a first inductance 3N 3 of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of a first inductance 3N 3 of the N line is an output end of the inductance filtering branch of the N line, a junction 1 of the first inductance 3 of the 3 line, a first resistance R3, a first capacitance C3 and a first junction 2 of the first inductance filtering branch of the N3 of the N line are sequentially connected with the first inductance filtering branch, and the junction of the third inductance R3 line 3 and the junction of the N3 line.
The invention concept of the application is as follows:
the technical problem to be solved by the invention is to provide an isolation circuit applied to a power line carrier test system, wherein the isolation circuit realizes that a 220V/10A power line passes through the isolation circuit without loss through an x-order low-pass filter technology, and the attenuation of 75dB or more is achieved in a carrier frequency range of 100 KHz-12 MHz, so that a cleaner test environment is provided for carrier equipment.
First, the main subject of the solution is an x-order low-pass filter. In the prior art, a resistor is connected with a capacitor in series in each branch trunk circuit and then connected with the main trunk circuit so as to attenuate signals. However, each branch trunk adopts a resistor and capacitor series connection mode, which causes the limitation of the signal attenuation capability of the isolator, and other carrier signals or interference signals cannot be isolated in the carrier test system, thereby affecting the test of the carrier module. The inventor finds that the attenuation capacity of the isolator can be effectively improved by modifying the traditional filter to change the resistance value of the x +1 level branch circuit series resistor, namely the last level branch circuit series resistor, to 25-50 ohms and removing other branch circuit series resistors.
Second, a high current high frequency inductor. The inductance parameter of the prior art is generally large inductance, small rated current, large inductance, large rated current and low working frequency, and the inductance can not be applied to a carrier test system of 10A, 100 KHz-12 MHz. The inventor finds that the 10A, 100 KHz-12 MHz working condition can be met by adopting the nickel-zinc high-frequency magnetic ring and the manganese-zinc low-frequency magnetic ring to combine and wind the inductor.
Technical contribution of the present application:
in order to solve the technical problem, the invention adopts the technical scheme that an x-order L C low-pass filter circuit, high-frequency large-current inductors LL (1 ﹍ x) and L N (1 ﹍ x), rated input impedance circuits R1 and C1, rated output impedance circuits Cx +1 and Rx +1, a power frequency input P1 port and a power frequency output P2 port are adopted.
The x-order L C low-pass filter circuit comprises two main trunk circuits formed by connecting x inductors in series and a middle branch circuit formed by connecting capacitors, wherein the middle branch circuit is formed by x-2 capacitors, and x is a natural number greater than 2.
The high-frequency large-current inductors LL (1 ﹍ x) and L N (1 ﹍ x) allow 10A of current to pass through and have rated inductance in a carrier frequency range of 100 KHz-12 MHz.
The rated input impedance circuits R1 and C1 are formed by connecting a branch 1 trunk capacitor C1 and a resistor R1 in series, and the capacitive reactance of the capacitor is very small and negligible in a carrier frequency band, so that the input impedance is almost equal to the resistance value of the resistor R1.
The rated output impedance circuits Cx +1 and Rx +1 are formed by connecting an xth branch circuit capacitor CX +1 and a resistor RX +1 in series, and similarly, the output impedance is almost equal to the resistance value of the resistor RX + 1.
The power frequency input P1 port refers to an isolator 220V/50Hz input port.
The power frequency output P2 port refers to an isolator 220V/50Hz output port.
In the above scheme, the attenuation value of the isolation circuit is:
A＝20log(Ax×Ax-1×A2)
wherein A is the attenuation value of the isolation circuit, AiIs the attenuation value of the i-order low-pass filter, f is the signal frequency, Rx+1Is branch x +1 trunk resistance, Cx+1For branch x +1 trunk safety regulation capacitance, LLxL N is a main line L x high-frequency large-current inductorxIs a main line Nx high-frequency large-current inductor, Ci+1For the i +1 branch trunk safety-regulation capacitance, LLiL N high-frequency large-current inductor for main line L iiThe Ni high-frequency large-current inductor is a main line Ni high-frequency large-current inductor, and i is a natural number which is larger than 1 and smaller than x-1.
The further technical scheme is as follows: the value range of the rated input impedance circuit resistor R1 is 0-50 ohms, and when the value of the resistor is 0 ohm, the isolation effect is optimal; with the increase of the resistance value of the resistor, the isolation effect is gradually reduced; the maximum resistance allowed is 50 ohms; the rated input impedance circuit resistor R1 is a chip resistor and has good high-frequency performance.
The further technical scheme is as follows: the resistor R3 of the rated output impedance circuit has the value range of 25-50 ohms, when the resistor R3 is 0 ohm, the isolation effect is optimal, but the performance of the tested carrier module is affected, so the resistor R3 is not recommended to be adopted, and the optimal value range is 25-50 ohms. The rated input impedance circuit resistor R3 is a chip resistor and has good high-frequency performance.
The further technical scheme is that with the increase of the working frequency, the characteristics of LL (1 ﹍ x), L N (1 ﹍ x), C1 and Cx +1 are changed, namely the self-resonant frequency exists, when the working frequency is higher than the self-resonant frequency, the inductor presents a capacitive property, and the capacitor presents an inductive property, so that the high-frequency high-current inductors LL (1 ﹍ x) and L N (1 ﹍ x) need to have a self-resonant frequency point higher than 12MHz, in the technical scheme, the high-frequency high-current inductors LL (1 ﹍ x) and L N (1 ﹍ x) are formed by double-magnetic-ring conducting wires of a nickel-zinc high-frequency magnetic ring and a manganese-zinc low-frequency magnetic ring, the nickel-zinc high-frequency magnetic ring has low magnetic permeability and high resistivity, the inductor is ensured to still present an inductive property under the high frequency, the manganese-zinc low-frequency magnetic ring has high magnetic permeability and low resistivity, and.
The technical scheme is as follows:
example 1 illustrates that:
as shown in FIG. 1, the invention discloses an isolation circuit applied to a power line carrier test system, which comprises an x-order L C low-pass filter circuit, high-frequency large-current inductors LL (1 ﹍ x) and L N (1 ﹍ x), rated input impedance circuits R1 and C1, rated output impedance circuits Cx +1 and Rx +1, a power frequency input P1 port and a power frequency output P2 port, wherein the power frequency input P1 port is used for accessing a 220V/50Hz power line, the power line contains a 100 KHz-12 MHz carrier signal and other high-frequency interference signals, the signals are attenuated to signals having no influence on the carrier test system after passing through the rated input impedance circuits R1 and C1 and the x-order L C low-pass filter, the rated output impedance circuits Cx +1 and Rx +1 provide rated impedance for the carrier test system, the power frequency output P2 port is accessed to the carrier test system, and the power line is provided with clean power line.
Example 2 illustrates that:
as shown in fig. 2, in simplified embodiment 1, the rated input impedance circuit is formed by only C1, and the isolation circuit includes a 4-step L C low-pass filter circuit, high-frequency large-current inductors LL 1, L N1, LL 2, L N2, a rated output impedance circuit C3, and R3.
Example 3 illustrates that:
as shown in fig. 3, in the technique of embodiment 2, rated input impedance circuits R1 and C1 are added. The isolation circuit has a rated input impedance and a rated output impedance, and although the isolation performance of embodiment 3 is slightly inferior to that of embodiment 2, the isolation circuit can be applied to a carrier-level communication structure.
As shown in fig. 4, it is a schematic diagram of the 220V/50Hz power line accessed in the embodiments 2 and 3, and the branch circuit is disconnected from the power line, and the power line is inputted from the power frequency input port P1, passed through the high frequency large current inductors LL 1, L N1, LL 2, L N2, and outputted from the power frequency output port P2.
FIG. 5 shows a circuit diagram of the 220V/50Hz power line access in the embodiment 2:
Rinis the power line source impedance, RinThe input equivalent impedance formed by the input rated impedance circuit and the 4 th-order L C low-pass filter circuit is as follows:
wherein R ise-5The equivalent impedance is input for fig. 5.
Isolation circuit output impedance Ro-2Comprises the following steps:
at this time, the attenuation values of the isolation circuit are:
wherein A isfig5The attenuation values of fig. 5.
If taking C1＝C2＝C3＝C，LL1＝LN1＝LN2＝LN2L, the attenuation value of the isolation circuit is:
FIG. 6 shows the circuit diagram of the 220V/50Hz power line access in the embodiment 3:
Rinis the power line source impedance, RinAnd an input rated impedance circuit,The input equivalent impedance formed by the 4 th-order L C low-pass filter circuit is as follows:
wherein R ise-6The equivalent impedance is input for fig. 6.
Isolation circuit output impedance Ro-3Comprises the following steps:
at this time, the attenuation values of the isolation circuit are:
wherein A isfig6The attenuation values of fig. 6.
If taking C1＝C2＝C3＝C，LL1＝LN1＝LN2＝LN2L, the attenuation value of the isolation circuit is:
as shown in FIG. 7, the simulation results of the amplitude-frequency characteristics, R, of the embodiment of FIG. 5 are obtainedinIs 50 ohm, R1Is 0 ohm, R3Is 50 ohm, C1＝C2＝C3＝220nF，LL1＝LN1＝LN2＝LN2As 470uH, the attenuation of the isolation circuit at 100KHz is about 76dB, and the attenuation increases as the frequency of the signal increases.
As shown in FIG. 8, the simulation results of the amplitude-frequency characteristics, R, of the embodiment of FIG. 6 were obtainedinIs 50 ohm, R1＝R3Is 50 ohm, C1＝C2＝C3＝220nF，LL1＝LN1＝LN2＝LN2470uH, the attenuation of the isolation circuit at 100KHz is known to be about65dB, compared to FIG. 5, the attenuation performance of example 3 is 11dB lower than that of example 2. This result is best matched with the isolation performance mentioned in the above solution when R1 is 0 ohms.
As shown in FIG. 9, the 220V/50Hz power line can pass through the present embodiment 2 and the present embodiment 3 without distortion by simulating the 220V/50Hz power line input for the embodiment 2 and the embodiment 3. Similarly, the present embodiment 1 may be applied without distortion.
After the application runs secretly for a period of time, the feedback of field technicians has the advantages that:
firstly, the isolation effect is good. Through actual test, the isolator can realize that the 220V/10A power line passes through without loss, and can attenuate signals within a frequency band of 100 KHz-12 MHz to 75dB or above, thereby meeting the isolation requirement of a carrier test system.
Secondly, in the x +1 branch trunk circuit, the 1 st branch trunk circuit and the x +1 st branch trunk circuit are removed, and the middle x-2 branch trunk circuit capacitor is directly connected with the two trunk circuits without series resistors, so that the cost is reduced.
And thirdly, the performance of the carrier module tested by the carrier testing system is not influenced.
Claims (10)
1. The isolation circuit applied to the power line carrier test system is characterized by comprising an inductance filtering branch circuit, a rated input impedance branch circuit and a rated output impedance branch circuit, wherein the inductance filtering branch circuit consists of L-line inductance filtering branch circuits with the same structure and an N-line inductance filtering branch circuit, the rated input impedance branch circuit is connected between the input end of the L-line inductance filtering branch circuit and the input end of the N-line inductance filtering branch circuit, and the rated output impedance branch circuit is connected between the output end of the L-line inductance filtering branch circuit and the output end of the N-line inductance filtering branch circuit.
2. The isolation circuit applied to the power line carrier test system according to claim 1, wherein the inductance filtering branch of the L line is a first inductance L0L of L line, the inductance filtering branch of the N line is a first inductance L2N 1 of the N line, the rated input impedance branch is formed by connecting a first resistance R1 and a first capacitance C1, the rated output impedance branch is formed by connecting a third resistance R3 and a third capacitance C3, the junction 1 of the first inductance 3 of the 3 line of 3 line is an input end of the inductance filtering branch of 3 line, the junction 2 of the first inductance 3 of the 3 line of 3 line is an output end of the inductance filtering branch of the 3 line, the junction 1 of the first inductance 3N 3 of the N line is an input end of the inductance filtering branch of the N line, the junction 2 of the first inductance 3N 3 of the N line is an output end of the inductance filtering branch of the N line, the first inductance filtering branch of the N line 3N line is a junction 1 of the first inductance filtering branch of the N line 3N line, the first inductance filtering branch of the N line 3 line is a junction 2 of the N line, the first inductance filtering line of the N line 3, the first inductance filtering line is a junction of the first inductance filtering line 3, the first inductance filtering line, the junction R72, the first inductance filtering line is a junction 72, and the junction 3 of the first inductance filtering line.
3. The isolation circuit applied to the power line carrier testing system according to claim 1, wherein the inductance filtering branch of the line comprises a first inductance 0 and a second inductance 12 of the line, the inductance filtering branch of the N line comprises a first inductance 3N and a second inductance 5N of the N line, the rated input impedance branch is a first capacitance C, the rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a junction 2 of the first inductance 41 of the 6 line is connected with a junction 1 of the second inductance 8 92 of the 7 line, a junction 1 of the first inductance 1 of the 0 line is an input end of the inductance filtering branch of the 2 line, a junction 2 of the second inductance 12 of the 3 line is an output end of the inductance filtering branch of the 5 line, a junction 2 of the first inductance N of the N line is connected with a junction 1 of the second inductance N of the N line, a junction 1 of the first inductance filtering branch of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of the second inductance N of the N line is an output end of the inductance filtering branch of the N line, a junction 2 of the first inductance filtering branch of the N line is sequentially connected with a junction of the third inductance C, a junction 2 of the second inductance filtering branch of the N and a junction of the third inductance C2 of the N.
4. The isolation circuit applied to the power line carrier testing system as claimed in claim 3, further comprising a capacitive filtering branch, wherein the capacitive filtering branch is a second capacitor C2, and the second capacitor C2 is connected between a connection of the first inductor LL 1 of L and the second inductor LL 2 of L and a connection of the first inductor L N1 of N and the second inductor L N2 of N.
5. The isolation circuit applied to the power line carrier test system according to claim 1, wherein the inductance filtering branch of the line comprises a first inductance 0 and a second inductance 12 of the line, the inductance filtering branch of the N line comprises a first inductance 3N and a second inductance 5N of the N line, the rated input impedance branch is formed by connecting a first resistance R and a first capacitance C, the rated output impedance branch is formed by connecting a third resistance R and a third capacitance C, a junction 2 of the first inductance 41 of the 6 line is connected with a junction 1 of the second inductance 8 of the 7 line, a junction 1 of the first inductance 1 of the 0 line is an input end of the inductance filtering branch of the 2 line, a junction 2 of the second inductance 12 of the 3 line is an output end of the inductance filtering branch of the 5 line, a junction 2 of the first inductance N of the N line is connected with a junction 1 of the second inductance N of the N line, a junction 1 of the first inductance N of the N line is an input end of the inductance filtering branch of the N line, a junction 2 of the second inductance N of the N line is an output end of the inductance filtering branch, a junction 2 of the second inductance of the N line is sequentially connected with a junction 1 of the third inductance filtering branch, a junction of the N of the inductor C2 of the N and a junction of the inductor C2 of the junction of the N line.
6. The isolation circuit applied to the power line carrier testing system as claimed in claim 5, further comprising a capacitive filtering branch, wherein the capacitive filtering branch is a second capacitor C2, and the second capacitor C2 is connected between a connection of the first inductor LL 1 of L and the second inductor LL 2 of L and a connection of the first inductor L N1 of N and the second inductor L N2 of N.
7. The isolation circuit applied to the power line carrier test system according to claim 2 or 5, wherein: the first resistor R1 is a resistor with a value range of 0 ohm to 50 ohm, and the first resistor R1 is a chip resistor.
8. The isolation circuit applied to the power line carrier test system according to claim 7, wherein: the first resistor R1 is a 0 ohm resistor.
9. The isolation circuit applied to the power line carrier test system according to claim 2, 3 or 5, wherein: the third resistor R3 is a resistor with a value range of 25-50 ohms, and the third resistor R3 is a chip resistor.
10. The isolation circuit applied to the power line carrier test system according to claim 1, wherein: the rated input impedance branch comprises a first resistor R1 and a first capacitor C1, and the first resistor R1 is connected with the first capacitor C1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010431386.7A CN111490809A (en) | 2020-05-20 | 2020-05-20 | Isolation circuit applied to power line carrier test system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010431386.7A CN111490809A (en) | 2020-05-20 | 2020-05-20 | Isolation circuit applied to power line carrier test system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111490809A true CN111490809A (en) | 2020-08-04 |
Family
ID=71796489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010431386.7A Pending CN111490809A (en) | 2020-05-20 | 2020-05-20 | Isolation circuit applied to power line carrier test system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111490809A (en) |
-
2020
- 2020-05-20 CN CN202010431386.7A patent/CN111490809A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110572024A (en) | EMI power filter | |
| CN104502755B (en) | Gaussian even pulse high-current high-power broadband power line injection coupling network and construction method thereof | |
| JPS63197109A (en) | Vanishing low pass filter | |
| TW200404419A (en) | Common-mode signal suppressing circuit and normal-mode signal suppressing circuit | |
| US7136270B2 (en) | Surge protector including data pass-through | |
| US4878244A (en) | Electronic hybrid circuit | |
| CN104502861A (en) | Gaussian even pulse high-current high-power broadband power wire injection coupling network and construction method thereof | |
| US4849685A (en) | Measuring and limiting EMI with a differential mode rejection network | |
| CN101505174A (en) | Interface circuit and method for suppressing electromagnetic interference | |
| JP2003283390A (en) | Inductor loading apparatus for power line carrier communication | |
| CN111490809A (en) | Isolation circuit applied to power line carrier test system | |
| CN212258956U (en) | Isolation circuit applied to power line carrier test system | |
| So et al. | Development of a test bed for power line communications | |
| Sibanda et al. | Passive, transformerless coupling circuitry for narrow-band power-line communications | |
| CN204119243U (en) | A kind of across frequency band bidirectional power line carrier channel analogue means | |
| CN114900149B (en) | Low-pass filter and optical communication testing device | |
| da Silva Costa et al. | An analog filter bank-based circuit for performing the adaptive impedance matching in PLC systems | |
| CN113746320B (en) | Filter circuit, power supply circuit and electric equipment | |
| CN101207368A (en) | Wave filter circuit | |
| Martínez et al. | Design of a T-coupling circuit for PLC on broadband | |
| CN210867500U (en) | EMI power filter | |
| US4275368A (en) | EMC-/EMI-filter module | |
| JP4729455B2 (en) | Filter circuit | |
| CN108347264B (en) | Impedance transformation equipment in power line broadband carrier communication test circuit | |
| CN109525201B (en) | Impedance matching method of radio frequency circuit and radio frequency circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20211216 Address after: 050021 No. 238 South Sports street, Hebei, Shijiazhuang Applicant after: STATE GRID HEBEI ELECTRIC POWER Research Institute Applicant after: Marketing service center of State Grid Hebei Electric Power Co.,Ltd. Applicant after: STATE GRID HEBEI ENERGY TECHNOLOGY SERVICE Co.,Ltd. Applicant after: STATE GRID CORPORATION OF CHINA Address before: 050021 No. 238 South Sports street, Hebei, Shijiazhuang Applicant before: STATE GRID HEBEI ELECTRIC POWER Research Institute Applicant before: STATE GRID HEBEI ENERGY TECHNOLOGY SERVICE Co.,Ltd. Applicant before: STATE GRID CORPORATION OF CHINA |