Power line communication frequency dynamic adjustment method for ensuring lowest communication attenuation degree

Abstract

The invention discloses a power line communication frequency dynamic adjustment method for ensuring the lowest communication attenuation degree, and the method comprises the following steps: S1, building a low-voltage power line high-speed carrier communication system model which comprises a transmitter side, a power line channel side and a receiver side, the transmitter side comprises a signal generator and an output impedance Zout, the signal generator is a signal source, the generating end voltage of the signal source is Uin, and the receiving end voltage of the signal source is Uout; and S2, performing circuit simplification on the low-voltage power line high-speed carrier communication system model to form a low-voltage power line high-speed carrier communication system simplified model. The impedance matching characteristic is utilized, the power line channel impedance is dynamically adjusted by changing the frequency, it is guaranteed that the difference between the transmitter source input impedance and the power line channel impedance and the difference between the transmitter source input impedance and the receiver input impedance are minimum, and the good effect that the attenuation degree of HPLC on a power line channel is the lowest is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage power broadband carrier communication, and in particular to a method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation. Background Art

[0002] Power line carrier communication (PLC) is a data communication technology that uses power lines as a transmission medium. Because it can reuse existing power lines as data transmission channels without the need for additional communication lines, and can provide broadband access capabilities to meet the needs of high-speed data transmission, it is currently widely used in smart grids to support remote reading of smart meters, grid monitoring, demand response and other functions. According to the level of transmission line voltage, power line carrier communication can be divided into high-voltage carrier (35KV and above), medium-voltage carrier (10KV) and low-voltage carrier (380 / 220V). According to the bandwidth, the carrier signal can be divided into narrowband PLC and broadband PLC. Narrowband PLC uses frequency bands below 500KHz for communication, and replaces manual monthly meter reading with daily frozen meter reading services, laying the foundation for the digital construction of low-voltage power grids. However, narrowband PLC has no unified standard, cannot be interconnected, has a low overall rate and poor performance, and cannot support further development and in-depth application of services. To further meet the construction needs of the smart power Internet of Things, the applicable scenarios are becoming more and more diverse. Especially in the context of the promotion of policies such as whole-house intelligence and digital home, it has become a general trend to use low-voltage HPLC communication to achieve networking communication and interconnection within the substation area.

[0003] Although low-voltage HPLC communication has obvious advantages, since low-voltage power lines are not specially designed for data transmission, their channel characteristics are significantly different from traditional transmission lines and will be affected by cable materials and electromagnetic environment. At the same time, because the load on the power line will change with the switching and power regulation, the overall power line channel impedance is very time-varying, resulting in constant fluctuations in the noise applied to the channel. And because low-voltage HPLC mainly transmits high-frequency signals, the noise brought by the channel itself will directly affect the signal attenuation amplitude, causing the communication quality to decline.

[0004] In order to reduce the signal attenuation and improve the communication quality, repeaters or signal amplifiers are generally used to enhance the signal strength in areas with severe signal attenuation. However, due to the continuous change of the power line channel impedance itself, the areas with severe signal attenuation are not fixed. The location and number of repeaters or signal amplifiers are difficult to determine, and continuous adjustment by manpower is required. It is difficult to achieve real-time dynamic adjustment to ensure the lowest power line communication attenuation.

[0005] Therefore, it does not meet the existing needs. We propose a method for dynamically adjusting the power line communication frequency to ensure the lowest communication attenuation. Summary of the invention

[0006] The purpose of the present invention is to provide a method for dynamically adjusting the power line communication frequency to ensure the lowest communication attenuation, so as to solve the problem proposed in the above background technology that the power line channel impedance itself changes continuously, the area points with severe signal attenuation are not fixed, the location and number of installation of repeaters or signal amplifiers are difficult to determine, and continuous adjustment by manpower is required, making it difficult to achieve real-time dynamic adjustment to ensure the lowest power line communication attenuation.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation, comprising the following steps:

[0008] S1: Establish a low-voltage power line high-speed carrier communication system model. The low-voltage power line high-speed carrier communication system model includes the transmitter side, the power line channel side and the receiver side. The transmitter side includes a signal generator and an output impedance Z out , the signal generator is the signal source, and the voltage at the generating end of the signal source is U in , the receiving end voltage U of the signal source out ;

[0009] S2: Simplify the circuit of the low-voltage power line high-speed carrier communication system model to form a simplified model of the low-voltage power line high-speed carrier communication system;

[0010] S3: Using the impedance matching principle, the low-voltage power line high-speed carrier communication system is simplified into a simplified model to simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', and dynamically adjust the communication frequency of the signal source on the transmitter side to dynamically adjust and simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', so that the communication signal attenuation of the low-voltage power line high-speed carrier communication system is minimized.

[0011] Preferably, the low-voltage power line high-speed carrier communication system model is simplified in circuit to form a simplified model of the low-voltage power line high-speed carrier communication system, including making the signal source and the receiver side equivalent through the number of turns, so as to make the impedance of the transmitter side and the impedance of the receiver side in the low-voltage power line high-speed carrier communication system model equivalent to the power line channel side, thereby obtaining a simplified model of the low-voltage power line high-speed carrier communication system.

[0012] Preferably, Z in = Z x +Z in ', when Z out '=Z in ", the communication signal attenuation of the low-voltage power line high-speed carrier communication system is the lowest; Z in' is the equivalent input impedance of the receiver side after equivalent turns, Z x is the input impedance of the receiver, Z in '=Z in / N2 2 , where N2 2 is the number of inductor turns on the receiver side.

[0013] Preferably, the effective length of the power line channel side is l, the power line channel side includes power line impedance and load impedance, and the load impedance is Z load , the power line impedance includes the first section impedance Z L1 and the second impedance Z L2 ;

[0014] The overall impedance of the power line channel is Z x , the overall impedance Z of the power line channel side x The first impedance Z L1 、The second impedance Z L2 and load impedance Z load constitute.

[0015] Preferably, the first impedance Z L1 and the second impedance Z L2 Both include impedance and admittance. The value of the impedance is Z, and the value of the admittance is Y. L1 =Z L2 =Z+1 / Y.

[0016] Preferably, the impedance part Z=R+jωL, and the admittance part Y=G+jωC, wherein R is resistance, L is inductance, G is conductance, C is capacitance, j is an imaginary unit, and ω is an angular frequency.

[0017] Preferably, U out / N1=U out ',U out ' is the voltage of the signal source equivalent to the number of turns, where N1 is the number of inductor turns on the transmitter side.

[0018] Preferably, by dynamically adjusting the communication frequency of the signal source on the transmitter side, the communication frequency of the signal source on the transmitter side is dynamically adjusted by using the perturbation principle to adjust the simplified overall input impedance Z in ” and simplifies the overall output impedance Z out ', so as to minimize the attenuation of communication signals in the low-voltage power line high-speed carrier communication system.

[0019] Preferably, using the disturbance principle to dynamically adjust the communication frequency of the signal source on the transmitter side comprises the following steps:

[0020] Step 1: Monitor the voltage U at the generating end of the signal source before the disturbance at the current momentin , the receiving end voltage U of the signal source out And the communication frequency f0, read and calculate the attenuation value A0;

[0021] Step 2: Determine the current disturbance direction, adjust the step size △f according to the set frequency disturbance and read the communication frequency f0, determine the target frequency f according to the set frequency disturbance adjustment step size △f, the current disturbance direction and the current communication frequency f0, and set the communication frequency of the signal source on the transmitter side to the target frequency f for disturbance, and read the voltage U of the signal source after the disturbance. in , the receiving end voltage U of the signal source out , f, and A values;

[0022] Step 3: If A(n) after disturbance < A(n-1) before disturbance, continue disturbance in the current disturbance direction; if A(n) after disturbance > A(n-1) before disturbance, continue disturbance in the opposite direction of the current disturbance direction;

[0023] Step 4: When A(n) after disturbance - A(n-1) before disturbance = 0, end the adjustment process; when A(n) after disturbance - A(n-1) before disturbance is not equal to 0, repeat the disturbance process until A(n) after disturbance - A(n-1) before disturbance = 0, and take the communication frequency corresponding to A(n) after disturbance as the final communication frequency as the optimal communication frequency for the current working condition.

[0024] Preferably, the target frequency f is determined according to the set frequency disturbance adjustment step Δf, the current disturbance direction and the current communication frequency f0, including:

[0025] The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. To ensure the minimum signal attenuation, the current signal source communication frequency is continuously subjected to positive disturbance (+△f) until the signal source communication frequency f(n) corresponding to the current sampling point at the previous moment = the signal source communication frequency +△f corresponding to the current sampling point before the disturbance at the previous moment, i.e., the signal source communication frequency is set to f(n+1)=f(n)+△f;

[0026] The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f;

[0027] The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is wrong. In order to ensure the minimum signal attenuation, continue to perform positive disturbance (+△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)+△f;

[0028] The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment was wrong. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention disassembles the system into the transmitter side, the power communication line side and the receiver side by establishing a low-voltage HPLC model (i.e., a low-voltage power line high-speed carrier communication system model), simplifies the circuit of the low-voltage power line high-speed carrier communication system model, and divides the input impedance and output impedance using the impedance matching principle. Through simulation, it is found that under the condition of orderly change of broadband frequency, the attenuation characteristics of the input impedance and voltage amplitude-frequency characteristics of the system show a peak-valley alternating trend; using the above characteristics, the present invention proposes an adjustment method for achieving the minimum difference between the transmitter output impedance and the power line impedance and the receiver input impedance according to the dynamic adjustment frequency, and at the same time, relying on the unpredictable characteristics of the time-varying load on the power line, the adjustment stage is set to the trigger stage and the adjustment stage. First, an impedance monitoring point is set on the power line to determine whether the trigger condition exists, and when the input impedance change is sensed, the trigger is turned on to enter the adjustment stage. In the adjustment stage, by reading the frequency, the input voltage and output voltage corresponding to the signal generating end and the receiving end, the signal attenuation corresponding to different frequencies is compared, and the adjustment is made according to the frequency disturbance before and after, and the signal attenuation is stabilized at the frequency point corresponding to the lowest signal attenuation. The present invention makes full use of the HPLC circuit characteristics and impedance matching characteristics. When the power line impedance change is identified, the frequency is dynamically adjusted to achieve the optimal value corresponding to the lowest signal attenuation. Different from the traditional means of reducing signal attenuation through repeaters or amplifiers, the present invention can keenly capture the channel impedance change and realize real-time adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the low-pressure HPLC communication system model of the present invention;

[0032] Figure 2 It is a schematic diagram of the power line impedance model of the present invention;

[0033] Figure 3 It is a simplified circuit diagram of the HPLC communication system model of the present invention;

[0034] Figure 4 Schematic diagram of input and output impedance equivalents of the HPLC communication system of the present invention;

[0035] Figure 5 It is a graph showing the change trend of the input impedance and attenuation degree of the HPLC communication system of the present invention as the frequency increases;

[0036] Figure 6 It is a schematic diagram of impedance monitoring points of the HPLC communication system of the present invention;

[0037] Figure 7 It is a schematic diagram of the HPLC frequency perturbation adjustment process of the present invention. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] See also Figures 1 to 6 , an embodiment of the present invention provides: a method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation, comprising the following steps:

[0040] S1: Establish a low-voltage power line high-speed carrier communication system model. The low-voltage power line high-speed carrier communication system model includes the transmitter side, the power line channel side and the receiver side. The transmitter side includes a signal generator and an output impedance Z out , the signal generator is the signal source, and the voltage at the generating end of the signal source is U in , the receiving end voltage U of the signal source out , the effective length of the power line channel side is l, the power line channel side includes the power line impedance and the load impedance, and the load impedance is Z load , the power line impedance includes the first section impedance Z L1 and the second impedance Z L2 ;

[0041] The overall impedance of the power line channel is Z x , the overall impedance Z of the power line channel side x The first impedance Z L1 、The second impedance Z L2 and load impedance Z load constitute;

[0042] The first impedance ZL1 and the second impedance Z L2 Both include impedance and admittance. The value of the impedance is Z, and the value of the admittance is Y. L1 =Z L2 =Z+1 / Y;

[0043] The impedance part is Z=R+jωL, and the admittance part is Y=G+jωC, where R is resistance, L is inductance, G is conductance, C is capacitance, j is imaginary unit, and ω is angular frequency;

[0044] S2: Simplifying the circuit of the low-voltage power line high-speed carrier communication system model to form a simplified model of the low-voltage power line high-speed carrier communication system. Simplifying the circuit of the low-voltage power line high-speed carrier communication system model to form a simplified model of the low-voltage power line high-speed carrier communication system, including making the signal source and the receiver side equivalent through the number of turns, so as to make the impedance of the transmitter side and the impedance of the receiver side in the low-voltage power line high-speed carrier communication system model equivalent to the power line channel side, and obtain the simplified model of the low-voltage power line high-speed carrier communication system;

[0045] S3: Using the impedance matching principle, the low-voltage power line high-speed carrier communication system is simplified into a simplified model to simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', and dynamically adjust the communication frequency of the signal source on the transmitter side to dynamically adjust and simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', so that the communication signal attenuation of the low-voltage power line high-speed carrier communication system is minimized, Z in = Z x +Z in ', when Z out '=Z in ", the communication signal attenuation of the low-voltage power line high-speed carrier communication system is the lowest; Z in ' is the equivalent input impedance of the receiver side after equivalent turns, Z x is the input impedance of the receiver, Z in '=Z in / N2 2 , where N2 2 is the number of inductor turns on the receiver side, U out / N1=U out ',U out ' is the voltage of the signal source equivalent to the number of turns, where N1 is the number of inductor turns on the transmitter side.

[0046] By dynamically adjusting the communication frequency of the signal source on the transmitter side, including: using the perturbation principle to dynamically adjust the communication frequency of the signal source on the transmitter side to adjust the simplified overall input impedance Zin ” and simplifies the overall output impedance Z out ', so as to minimize the attenuation of communication signals in the low-voltage power line high-speed carrier communication system.

[0047] The communication frequency of the signal source on the transmitter side is dynamically adjusted using the disturbance principle, including the following steps:

[0048] Step 1: Monitor the voltage U at the generating end of the signal source before the disturbance at the current moment in , the receiving end voltage U of the signal source out And the communication frequency f0, read and calculate the attenuation value A0;

[0049] Step 2: Determine the current disturbance direction, adjust the step size △f according to the set frequency disturbance and read the communication frequency f0, determine the target frequency f according to the set frequency disturbance adjustment step size △f, the current disturbance direction and the current communication frequency f0, and set the communication frequency of the signal source on the transmitter side to the target frequency f for disturbance, and read the voltage U of the signal source after the disturbance. in , the receiving end voltage U of the signal source out , f, and A values;

[0050] Step 3: If A(n) after disturbance < A(n-1) before disturbance, continue disturbance in the current disturbance direction; if A(n) after disturbance > A(n-1) before disturbance, continue disturbance in the opposite direction of the current disturbance direction;

[0051] Step 4: When A(n) after disturbance - A(n-1) before disturbance = 0, end the adjustment process; when A(n) after disturbance - A(n-1) before disturbance is not equal to 0, repeat the disturbance process until A(n) after disturbance - A(n-1) before disturbance = 0, and take the communication frequency corresponding to A(n) after disturbance as the final communication frequency as the optimal communication frequency for the current working condition.

[0052] like Figure 7 As shown in the figure:

[0053] U in (n) is the voltage value of the signal generating terminal corresponding to the current sampling point;

[0054] U out (n) The voltage value of the receiving end corresponding to the current sampling point;

[0055] F(n) is the communication frequency of the signal source corresponding to the current sampling point;

[0056] A(n) is the signal attenuation value corresponding to the current sampling point (according to U in (n) and U out (n) calculated value);

[0057] A(n-1) is the signal attenuation value corresponding to the previous sampling point;

[0058] F(n-1) is the signal source communication frequency corresponding to the previous sampling point;

[0059] △f is the step size of frequency disturbance adjustment;

[0060] Y is judgment logic-yes;

[0061] N is the judgment logic - no.

[0062] The target frequency f is determined according to the set frequency disturbance adjustment step △f, the current disturbance direction and the current communication frequency f0, including:

[0063] The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. To ensure the minimum signal attenuation, the current signal source communication frequency is continuously subjected to positive disturbance (+△f) until the signal source communication frequency f(n) corresponding to the current sampling point at the previous moment = the signal source communication frequency +△f corresponding to the current sampling point before the disturbance at the previous moment, i.e., the signal source communication frequency is set to f(n+1)=f(n)+△f;

[0064] The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f;

[0065] The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is wrong. In order to ensure the minimum signal attenuation, continue to perform positive disturbance (+△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)+△f;

[0066] The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment was wrong. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f.

[0067] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation, characterized in that: The steps include: S1: Establish a low-voltage power line high-speed carrier communication system model. The low-voltage power line high-speed carrier communication system model includes the transmitter side, the power line channel side and the receiver side. The transmitter side includes a signal generator and an output impedance Z out , the signal generator is the signal source, and the voltage at the generating end of the signal source is U in , the receiving end voltage U of the signal source out ; S2: Simplify the circuit of the low-voltage power line high-speed carrier communication system model to form a simplified model of the low-voltage power line high-speed carrier communication system; S3: Using the impedance matching principle, the low-voltage power line high-speed carrier communication system is simplified into a simplified model to simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', and dynamically adjust the communication frequency of the signal source on the transmitter side to dynamically adjust and simplify the overall input impedance Z in ” and simplifies the overall output impedance Z out ', so that the communication signal attenuation of the low-voltage power line high-speed carrier communication system is minimized.

2. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 1, characterized in that: The circuit of the low-voltage power line high-speed carrier communication system model is simplified to form a simplified model of the low-voltage power line high-speed carrier communication system, including making the signal source and the receiver side equivalent through the number of turns, so as to make the impedance of the transmitter side and the impedance of the receiver side in the low-voltage power line high-speed carrier communication system model equivalent to the power line channel side, thereby obtaining a simplified model of the low-voltage power line high-speed carrier communication system.

3. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 2, characterized in that: Z in ”=Z x +Z in ', when Z out '=Z in ", the communication signal attenuation of the low-voltage power line high-speed carrier communication system is the lowest; Z in ' is the equivalent input impedance of the receiver side after equivalent turns, Z x is the input impedance of the receiver, Z in '=Z in / N2 2 , where N2 2 is the number of inductor turns on the receiver side.

4. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 1, characterized in that: The effective length of the power line channel side is l, and the power line channel side includes the power line impedance and the load impedance. The load impedance is Z load , the power line impedance includes the first section impedance Z L1 and the second impedance Z L2 ; The overall impedance of the power line channel is Z x , the overall impedance Z of the power line channel side x The first impedance Z L1 、The second impedance Z L2 and load impedance Z load constitute.

5. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 4, characterized in that: The first impedance Z L1 and the second impedance Z L2 Both include impedance and admittance. The value of the impedance is Z, and the value of the admittance is Y. L1 =Z L2 =Z+1 / Y.

6. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 5, characterized in that: The impedance part Z=R+jωL, the admittance part Y=G+jωC, where R is resistance, L is inductance, G is conductance, C is capacitance, j is imaginary unit, and ω is angular frequency.

7. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 3, characterized in that: U out / N1=U out ',U out ' is the voltage of the signal source equivalent to the number of turns, where N1 is the number of inductor turns on the transmitter side.

8. The method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 1, characterized in that: By dynamically adjusting the communication frequency of the signal source on the transmitter side, including: using the perturbation principle to dynamically adjust the communication frequency of the signal source on the transmitter side to adjust the simplified overall input impedance Z in ” and simplifies the overall output impedance Z out ', so as to minimize the attenuation of communication signals in the low-voltage power line high-speed carrier communication system.

9. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 8, characterized in that: The communication frequency of the signal source on the transmitter side is dynamically adjusted by utilizing the disturbance principle, including the following steps: Step 1: Monitor the voltage U at the generating end of the signal source before the disturbance at the current moment in , the receiving end voltage U of the signal source out And the communication frequency f0, read and calculate the attenuation value A0; Step 2: Determine the current disturbance direction, adjust the step size △f according to the set frequency disturbance and read the communication frequency f0, determine the target frequency f according to the set frequency disturbance adjustment step size △f, the current disturbance direction and the current communication frequency f0, and set the communication frequency of the signal source on the transmitter side to the target frequency f for disturbance, and read the voltage U of the signal source after the disturbance. in , the receiving end voltage U of the signal source out , f, and A values; Step 3: If A(n) after disturbance < A(n-1) before disturbance, continue disturbance in the current disturbance direction; if A(n) after disturbance > A(n-1) before disturbance, continue disturbance in the opposite direction of the current disturbance direction; Step 4: When A(n) after disturbance - A(n-1) before disturbance = 0, end the adjustment process; when A(n) after disturbance - A(n-1) before disturbance is not equal to 0, repeat the disturbance process until A(n) after disturbance - A(n-1) before disturbance = 0, and take the communication frequency corresponding to A(n) after disturbance as the final communication frequency as the optimal communication frequency for the current working condition.

10. A method for dynamically adjusting the frequency of power line communication to ensure the lowest communication attenuation according to claim 9, characterized in that: The target frequency f is determined according to the set frequency disturbance adjustment step △f, the current disturbance direction and the current communication frequency f0, including: The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. To ensure the minimum signal attenuation, the current signal source communication frequency is continuously subjected to positive disturbance (+△f) until the signal source communication frequency f(n) corresponding to the current sampling point at the previous moment = the signal source communication frequency +△f corresponding to the current sampling point before the disturbance at the previous moment, i.e., the signal source communication frequency is set to f(n+1)=f(n)+△f; The signal attenuation value A(n) corresponding to the current sampling point is less than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is correct. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f; The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point, and the signal source communication frequency f(n) corresponding to the current sampling point is less than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment is wrong. In order to ensure the minimum signal attenuation, continue to perform positive disturbance (+△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)+△f; The signal attenuation value A(n) corresponding to the current sampling point is greater than the signal attenuation value corresponding to the previous sampling point and the signal source communication frequency f(n) corresponding to the current sampling point is greater than the signal source communication frequency f(n-1) corresponding to the previous sampling point, indicating that the frequency disturbance direction at the previous moment was wrong. In order to ensure the minimum signal attenuation, continue to perform reverse disturbance (-△f) on the current signal source communication frequency, that is, set the signal source communication frequency to f(n+1)=f(n)-△f.

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