A carrier communication network noise absorbing system

Abstract

The application provides a carrier communication network noise absorption system, which comprises a power supply unit for supplying power for the system, a noise and PLC signal coupling unit for accessing a power line, a coupling capacitor and a coupling transformer circuit for filtering and outputting noise and PLC signals in the power line, and a PLUS pulse signal for reflecting whether the signal in the power line is a valid PLC signal according to the leading wave characteristics of the PLC signal package header; a noise absorption unit connected with the noise and PLC signal coupling unit, for applying different loads on the noise source of the power line, so that the noise energy is converted into heat energy and the noise voltage amplitude is reduced; and a PLC signal analysis unit connected with the noise and PLC signal coupling unit and the noise absorption unit, for performing peak value sampling on the noise and PLC signals output by the noise and PLC signal coupling unit, judging whether the current signal is a PLC signal or a noise signal, and controlling different loads to absorb the noise.

Description

Technical Field

[0001] This invention relates to the field of carrier communication network noise processing technology, and more specifically, to a carrier communication network noise absorption system. Background Technology

[0002] With the widespread application of power line carrier communication (PLC) technology in low-voltage network smart meters, this technology also faces challenges in field applications, especially in long-distance transmission and high-noise environments, where communication performance is very poor. The main source of noise is the prevalence of electronic products, many of which use switching power supply technology. This is particularly true for high-power devices such as air conditioners and induction cookers. At the user end of the meter, a large amount of switching noise (30kHz~80kHz) and a small amount of subharmonic noise (80kHz~500kHz) are superimposed on the power transmission line. This noise is generally white noise with a fixed power. Narrowband PLC communication technologies (G3, PRIME, etc.) operate in the 30kHz~500kHz frequency band, which overlaps with the noise generated by electronic products, thus affecting communication performance.

[0003] EMC filters are typically used to address these issues. However, when applied to low-voltage network meters, these filters need to be installed between the meter and the user. The filters need to handle currents of 60A, 100A, or even higher, making it difficult to meet standard requirements for reliability and temperature rise. Furthermore, even when there is no power consumption at the user end, the presence of the filter generates reactive power, affecting the accuracy of the meter readings. Additionally, these filters are usually large and inconvenient to install. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems in the prior art, namely, noise affecting communication performance, the reliability and temperature rise of filters in existing solutions are difficult to meet standard requirements, the presence of filters generates reactive power affecting the accuracy of electricity meter measurement, and the large size of filters, which is inconvenient for installation.

[0005] Therefore, the present invention provides a noise absorption system for carrier communication networks.

[0006] This invention provides a carrier communication network noise absorption system, comprising:

[0007] The power supply unit is used to supply power to the system.

[0008] The noise and PLC signal coupling unit is connected to the power line. It uses a coupling capacitor and coupling transformer circuit to filter the noise and PLC signal in the power line and output the noise and PLC signal. At the same time, it generates a PLUS pulse signal based on the preamble characteristics of the PLC signal packet to reflect whether the signal in the power line is a valid PLC signal.

[0009] The noise absorption unit, connected to the noise and PLC signal coupling unit, uses RC and MOS control circuits to apply different loads to the noise source on the power line, so that the noise energy is converted into heat energy, reducing the noise voltage amplitude and absorbing the noise voltage amplitude to be equal to or lower than the PLC signal amplitude.

[0010] The PLC signal analysis unit is connected to both the noise and PLC signal coupling unit and the noise absorption unit. After sampling the noise and PLC signal ADC output from the noise and PLC signal coupling unit, it sends the data to the DSP for OFDM modulation analysis to determine whether the current signal is a PLC signal or a noise signal. If the current signal is a PLC signal, it indicates that the noise absorption circuit is currently functioning correctly. If the current signal is not a PLC signal, it controls the noise absorption unit to absorb noise until the current signal is a PLC signal. If OFDM modulation analysis fails, the PLC signal analysis unit analyzes the PLUS pulse signal output from the noise and PLC signal coupling unit to determine whether the signal in the power line is a valid PLC signal. If the current signal is a valid PLC signal, it indicates that the noise absorption circuit is currently functioning correctly. If the current signal is not a valid PLC signal, it controls the noise absorption unit to absorb noise until the current signal is a PLC signal.

[0011] According to the above-described technical solution of the present invention, a quasi-zero stiffness vibration isolation device may further have the following additional technical features:

[0012] In the above technical solution, the power supply unit includes a varistor VR1, a wire-wound power resistor R15, a high-voltage safety capacitor C9, high-voltage rectifier diodes D8~D11, TVS diodes Z1 and Z2, electrolytic capacitors EC2 and EC3, and an LDO linear regulator U1.

[0013] The varistor VR1 is connected between the neutral and live wires; one end of the wire-wound power resistor R15 is connected to the input terminal of the live wire and one end of the varistor VR1, and the other end of the wire-wound power resistor R15 is connected to one end of the high-voltage safety capacitor C9. The other end of the high-voltage safety capacitor C9 is connected between the high-voltage rectifier diodes D9 and D11. The input terminal of the neutral wire is connected between the high-voltage rectifier diodes D8 and D10. The negative terminals of the high-voltage rectifier diodes D8 and D9 are connected, and the positive terminals of D10 and D11 are connected. The high-voltage rectifier diodes D8 to D11 form a rectifier bridge. TVS diodes Z1 and Z2 are connected in parallel between the two output terminals of the rectifier bridge. Electrolytic capacitors EC2 and EC3 are connected in parallel across the two ends of TVS diode Z2. The positive terminal of electrolytic capacitor EC3 is connected to the input terminal of the LDO linear regulator U1, and the output terminal of the LDO linear regulator U1 supplies power to the system.

[0014] In the above technical solution, the noise and PLC signal coupling unit includes a noise coupling circuit, a CENELEC-A bandpass filter, an FCC bandpass filter, and a PLUS pulse signal generation circuit. The input terminal of the noise coupling circuit is connected to the power line, and the output terminal is connected to the input terminals of the CENELEC-A bandpass filter and the FCC bandpass filter, respectively. The output terminal of the CENELEC-A bandpass filter outputs the peak-to-peak value Vpp_CA of the CENELEC-A band noise and the rectified DC value Vdc_CA. The output terminal of the FCC bandpass filter outputs the peak-to-peak value Vpp_FCC of the FCC band noise and the rectified DC value Vdc_FCC. The input terminal of the PLUS pulse signal generation circuit receives the Vpp_CA and Vpp_FCC signals and compares them with a reference voltage signal to output a PLUS pulse signal.

[0015] In the above technical solution, the noise coupling circuit includes a safety capacitor C2, a wound power inductor L4, and a signal coupling transformer T1. The live wire of the power line is connected to one end of the safety capacitor C2, and the other end of the safety capacitor C2 is connected to one end of the wound power inductor L4. The other end of the wound power inductor L4 is connected to the same-name terminal of the primary winding of the signal coupling transformer T1, and the neutral wire of the power line is connected to the opposite-name terminal of the primary winding of the signal coupling transformer T1. The same-name terminal and the opposite-name terminal of the secondary winding of the signal coupling transformer T1 output signal+ and signal- signals, respectively.

[0016] In the above technical solution, the number of turns in the primary winding of the signal coupling transformer T1 is less than the number of turns in the secondary winding.

[0017] In the above technical solution, the CENELEC-A bandpass filter is used to allow the center frequency of the CENELEC-A band to pass through better.

[0018] In the above technical solution, the FCC bandpass filter is used to allow the center frequency of the FCC band to pass through better.

[0019] In the above technical solution, the PLUS pulse signal generation circuit includes digital switches S1 and S2, comparator U100, MOSFETs Q101~Q109, and a voltage divider network; the voltage divider network includes resistor R100 and resistors R101~R109.

[0020] The Vpp_CA and Vpp_FCC signals are connected to the first input terminal of comparator U100 through digital switches S1 and S2, respectively. MOSFETs Q101~Q109 are connected to resistors R101~R109 in a one-to-one correspondence. Each MOSFET is used to control the resistor connected to it to the voltage divider network. The resistor connected to the voltage divider network is divided by resistor R100 and outputs a reference voltage signal. The reference voltage signal is connected to the second input terminal of comparator U100. The output terminal of comparator U100 outputs a PLUS pulse signal.

[0021] In the comparator U100, the reference voltage signal is compared with Vpp_FCC or Vpp_CA, the prelead wave SYNCP of the PLC signal packet is detected, and the comparator is triggered to output a high-level signal with equal amplitude and period using 10 sets of logic with equal amplitude and period of the prelead wave SYNCP, thus generating the PLUS pulse signal.

[0022] In the above technical solution, the noise absorption unit includes capacitors C41 and C42, diodes D41~D44, D46, and D47, rheostat D45, electrolytic capacitor EC41, resistors R41~R43, power resistors R44~R46, and field-effect transistors Q41~Q43.

[0023] The signal+ and signal- signals are connected to one end of capacitors C41 and C42, respectively.

[0024] The other end of capacitor C41 is connected to the positive terminal of diode D41, the negative terminal of diode D42, and one end of resistor R41, respectively. The positive terminal of diode D42 is grounded. The output signal V_REF+ of the PLC signal analysis unit is connected to the positive terminal of diode D46. The negative terminal of diode D46 is connected in parallel with the negative terminal of diode D41 and connected to the noise signal V_Noise of the power line.

[0025] The other end of capacitor C42 is connected to the positive terminal of diode D43, the negative terminal of diode D44, and the other end of resistor R41, respectively. The negative terminal of diode D43 is connected to the noise signal V_Noise of the power line. The output signal V_REF- of the PLC signal analysis unit is connected to the positive terminal of diode D47, and the negative terminal of diode D47 is connected to ground in parallel with the positive terminal of diode D41.

[0026] The power line noise signal V_Noise is connected to ground after passing through electrolytic capacitor EC41. Rheostat D45 is connected in parallel across electrolytic capacitor EC41. One end of power resistor R44 is connected to the drain of MOSFET Q41. One end of power resistor R45 is connected to the drain of MOSFET Q42. One end of power resistor R46 is connected to the drain of MOSFET Q43.

[0027] The other end of power resistor R44, the other end of power resistor R45, the other end of power resistor R46, one end of resistor R42, and one end of resistor R43 are connected in parallel to the positive terminal of electrolytic capacitor EC41.

[0028] The source terminals of field-effect transistors Q41, Q42, and Q43, the other end of resistor R42, and the other end of resistor R43 are connected to ground in parallel.

[0029] The gates of field-effect transistors Q41, Q42, and Q43 are connected to the load control signals Load_1, Load_2, and Load_3, respectively.

[0030] In the above technical solution, the PLC signal analysis unit includes an ADC module, a DSP module, and a DAC module;

[0031] The peak-to-peak value Vpp_CA of the noise in the CENELEC-A band and the rectified DC value Vdc_CA of the ADC module, and the peak-to-peak value Vpp_FCC of the noise in the FCC band and the rectified DC value Vdc_FCC of the ADC module.

[0032] The DSP module performs OFDM digital analysis on the signals input to the ADC module and analyzes the PLC signals;

[0033] Statistically determine whether the number of periodic peaks in the sampling results is the same as the number of periodic peak-to-peak voltage signals measured in the package head, and record the signal peak value and / or root mean square value; input the peak value and / or root mean square value into the DAC module, and the DAC module outputs voltage signals V_REF+ and VREF-;

[0034] If they are the same, it is determined that the signal connected to the ADC module is a PLC signal; if they are different, it is determined that the signal connected to the ADC module is noisy. Then, Q41, Q42, and Q43 in the noise absorption unit are controlled to apply the power resistor to the noise source of the power line to absorb the noise until the number of equal periodic peaks in the sampling result is the same as the number of equal periodic peak-to-peak voltage signals in the measured package.

[0035] If the noise signal is complex, causing the DSP to fail to perform OFDM digital analysis, the DSP will analyze the analog signal. The DSP will detect the PLUS pulse signal and count the high levels. If the PLUS pulse signal records 10 equal-period high-level pulses, the current signal is considered a valid PLC signal. If 10 equal-period high-level pulses cannot be detected, it is determined that the noise signal is greater than the PLC signal. The DSP will then control Q41, Q42, and Q43 in the noise absorption unit to apply power resistors to the noise source on the power line to absorb the noise.

[0036] In the above technical solution, the PLC signal analysis unit is equipped with an LED indicator light, which is used to indicate the strength of noise. The stronger the noise, the faster the LED light flashes.

[0037] In summary, due to the adoption of the above-mentioned technical features, the beneficial effects of the present invention are:

[0038] This invention is based on the principle that noise is also energy, specifically energy beyond the usable energy of 50Hz power lines. It separates this energy from the 50Hz AC power and uses a power load to convert the noise energy into heat, thereby reducing the noise amplitude. It can be portablely installed at the terminals of an electricity meter, effectively absorbing noise based on the amplitude of the communication signal. It can effectively replace traditional filter circuits, overcoming problems such as large size, temperature rise, and inconvenient installation. It can achieve digital automatic adjustment of the filter based on the magnitude of the noise amplitude and the PLC signal amplitude.

[0039] By utilizing the fact that noise is generally white noise and the power is constant, different loads are added, causing the noise energy to be converted into heat energy of the load and consumed, thereby reducing the noise voltage amplitude and improving the signal-to-noise ratio.

[0040] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0042] Figure 1 This is a schematic diagram of a carrier communication network noise absorption system according to an embodiment of the present invention;

[0043] Figure 2 This is a circuit diagram of a power supply unit in a carrier communication network noise absorption system according to an embodiment of the present invention.

[0044] Figure 3 This is a circuit diagram of a noise coupling circuit in a noise coupling unit of a carrier communication network noise absorption system according to an embodiment of the present invention.

[0045] Figure 4 This is a circuit schematic diagram of a CENELEC-A bandpass filter in a noise coupling unit of a carrier communication network noise absorption system according to an embodiment of the present invention.

[0046] Figure 5 This is a circuit schematic diagram of an FCC bandpass filter in a noise coupling unit of a carrier communication network noise absorption system according to an embodiment of the present invention.

[0047] Figure 6 This is a circuit diagram of a PLUS pulse signal generation circuit in a carrier communication network noise absorption system according to an embodiment of the present invention.

[0048] Figure 7 This is a waveform diagram of the PLC signal in the time domain;

[0049] Figure 8 This is a circuit diagram of a noise absorption unit in a carrier communication network noise absorption system according to an embodiment of the present invention;

[0050] Figure 9 This is a time-domain waveform diagram showing noise levels greater than those of the PLC signal.

[0051] Figure 10 This is a detailed time-domain waveform of noise and PLC signal during operation of a carrier communication network noise absorption system according to an embodiment of the present invention;

[0052] Figure 11 This is a waveform diagram illustrating the working process of a carrier communication network noise absorption system according to an embodiment of the present invention.

[0053] Figure 12 This is an external structural diagram of a carrier communication network noise absorption system according to an embodiment of the present invention;

[0054] Figure 13 This is a schematic diagram of a noise absorption unit fixing method in a carrier communication network noise absorption system according to an embodiment of the present invention;

[0055] Figure 14 This is an internal structural diagram of a noise absorption unit in a carrier communication network noise absorption system according to an embodiment of the present invention.

[0056] in, Figures 12 to 14 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0057] 1. Noise absorber; 2. Original terminals of the electricity meter;

[0058] 11. Screw; 12. PCB board; 13. Spring. Detailed Implementation

[0059] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0060] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0061] The following reference Figures 1 to 14 This describes a carrier communication network noise absorption system provided according to some embodiments of the present invention.

[0062] Some embodiments of this application provide a noise absorption system for a carrier communication network.

[0063] like Figure 1 As shown, the first embodiment of the present invention proposes a carrier communication network noise absorption system, comprising:

[0064] The power supply unit is used to supply power to the system.

[0065] The noise and PLC signal coupling unit is connected to the power line. It uses a coupling capacitor and coupling transformer circuit to filter the noise and PLC signal in the power line and output the noise and PLC signal. At the same time, it generates a PLUS pulse signal based on the preamble characteristics of the PLC signal packet to reflect whether the signal in the power line is a valid PLC signal.

[0066] The noise absorption unit, connected to the noise and PLC signal coupling unit, uses RC and MOS control circuits to apply different loads to the noise source on the power line, so that the noise energy is converted into heat energy, reducing the noise voltage amplitude and absorbing the noise voltage amplitude to be equal to or lower than the PLC signal amplitude.

[0067] The PLC signal analysis unit is connected to both the noise and PLC signal coupling unit and the noise absorption unit. After sampling the noise and PLC signal ADC output from the noise and PLC signal coupling unit, it sends the data to the DSP for OFDM modulation analysis to determine whether the current signal is a PLC signal or a noise signal. If the current signal is a PLC signal, it indicates that the noise absorption circuit is currently functioning correctly. If the current signal is not a PLC signal, it controls the noise absorption unit to absorb noise until the current signal is a PLC signal. If OFDM modulation analysis fails, the PLC signal analysis unit analyzes the PLUS pulse signal output from the noise and PLC signal coupling unit to determine whether the signal in the power line is a valid PLC signal. If the current signal is a valid PLC signal, it indicates that the noise absorption circuit is currently functioning correctly. If the current signal is not a valid PLC signal, it controls the noise absorption unit to absorb noise until the current signal is a PLC signal.

[0068] In this embodiment, the power supply unit is used to supply power to all units in the entire system and is connected to the noise and PLC signal coupling unit, the noise absorption unit, and the PLC signal analysis unit. An RC power supply circuit is used. Since the system power consumption is only 0.1W, it will not consume a large amount of grid energy after the equipment is installed, causing power loss and no secondary pollution to the grid. It is safe and reliable.

[0069] The noise and PLC signal coupling unit is used to couple noise and PLC signals from the power line. Its purpose is to completely separate signals above 30kHz from the 50Hz power line network. It employs coupling capacitors and a coupling transformer circuit, allowing for detailed analysis of noise from 30kHz to 500kHz. Simultaneously, it acquires noise voltage values, including the peak-to-peak value Vpp_CA and rectified DC value Vdc_CA for the CENELEC-A band noise, and the peak-to-peak value Vpp_FCC and rectified DC value Vdc_FCC for the FCC band noise. Furthermore, through a backup noise and PLC signal detection circuit, namely the PLUS pulse signal generation circuit, it outputs a PLUS pulse signal and transmits it to the PLC signal analysis unit, preventing the DSP from being unable to interpret the signal under conditions of high noise complexity.

[0070] The purpose of the PLC signal analysis unit is to determine the peak-to-peak value of the PLC communication signal voltage. It uses ADC, DSP, and DAC circuits and takes advantage of the characteristic protocol that each data packet header of the narrowband PLC signal has the same amplitude and period to collect the peak-to-peak value of the PLC signal amplitude. When the signal can be collected, it indicates that the current state of the noise absorption circuit is reasonable.

[0071] The noise absorption unit aims to absorb the noise voltage amplitude to be equal to or lower than the PLC signal amplitude. It uses RC and MOS control circuits to apply different loads to the noise source on the power line, so that the noise energy is converted into heat energy and the noise voltage amplitude is reduced.

[0072] The second embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on the first embodiment, as follows: Figure 2 As shown, the power supply unit includes a varistor VR1, a wire-wound power resistor R15, a high-voltage safety capacitor C9, high-voltage rectifier diodes D8~D11, TVS diodes Z1 and Z2, electrolytic capacitors EC2 and EC3, and an LDO linear regulator U1.

[0073] The varistor VR1 is connected between the neutral and live wires; one end of the wire-wound power resistor R15 is connected to the input terminal of the live wire and one end of the varistor VR1, and the other end of the wire-wound power resistor R15 is connected to one end of the high-voltage safety capacitor C9. The other end of the high-voltage safety capacitor C9 is connected between the high-voltage rectifier diodes D9 and D11. The input terminal of the neutral wire is connected between the high-voltage rectifier diodes D8 and D10. The negative terminals of the high-voltage rectifier diodes D8 and D9 are connected, and the positive terminals of D10 and D11 are connected. The high-voltage rectifier diodes D8 to D11 form a rectifier bridge. TVS diodes Z1 and Z2 are connected in parallel between the two output terminals of the rectifier bridge. Electrolytic capacitors EC2 and EC3 are connected in parallel across the two ends of TVS diode Z2. The positive terminal of electrolytic capacitor EC3 is connected to the input terminal of the LDO linear regulator U1, and the output terminal of the LDO linear regulator U1 supplies power to the system.

[0074] In this embodiment, TVS diodes Z1 and Z2 are 15V, 1500W TVS diodes. This unit utilizes the impedance characteristics of R15 and C9 in 50Hz AC to provide current to TVS diodes Z1 and Z2, clamping the voltage across Z1 and Z2 to 15V. High-voltage rectifier diodes D8~D11, electrolytic capacitors EC2 and EC3 constitute a rectifier and filter circuit, converting the 15V AC voltage output from the RC power supply circuit into DC voltage. Then, an LDO linear regulator U1 converts the voltage to +5V to power the system. Preferably, an additional LDO linear regulator U2 can be added to convert the voltage to -5V.

[0075] The third embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figures 3 to 6 As shown, the noise and PLC signal coupling unit includes a noise coupling circuit, a CENELEC-A bandpass filter, an FCC bandpass filter, and a PLUS pulse signal generation circuit. The input of the noise coupling circuit is connected to the power line, and its output is connected to the inputs of the CENELEC-A bandpass filter and the FCC bandpass filter, respectively. The output of the CENELEC-A bandpass filter outputs the peak-to-peak value Vpp_CA of the CENELEC-A band noise and the rectified DC value Vdc_CA. The output of the FCC bandpass filter outputs the peak-to-peak value Vpp_FCC of the FCC band noise and the rectified DC value Vdc_FCC. The input of the PLUS pulse signal generation circuit receives the Vpp_CA and Vpp_FCC signals and compares them with a reference voltage signal to output a PLUS pulse signal.

[0076] In this embodiment, after passing through two bandpass filters, Vpp_CA and Vdc_CA, and Vpp_FCC and Vdc_FCC are generated, representing the peak-to-peak value and rectified DC value of the noise in the CENELEC-A band, and the peak-to-peak value and rectified DC value of the noise in the FCC band, respectively. These noise signals are sampled by the ADC module of the PLC signal analysis unit and analyzed by the DSP module. This allows for accurate analysis of the frequency band and location of the noise. Simultaneously, by comparing the peak-to-peak value and the rectified DC value of the noise, the noise type (continuous or discontinuous), the noise period, the time of day the noise occurs, and the approximate source of the noise from the equipment.

[0077] The fourth embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figure 3 As shown, the noise coupling circuit includes a safety capacitor C2, a wound power inductor L4, and a signal coupling transformer T1. The live wire of the power line is connected to one end of the safety capacitor C2, and the other end of the safety capacitor C2 is connected to one end of the wound power inductor L4. The other end of the wound power inductor L4 is connected to the same-name terminal of the primary winding of the signal coupling transformer T1, and the neutral wire of the power line is connected to the opposite-name terminal of the primary winding of the signal coupling transformer T1. The same-name terminal and the opposite-name terminal of the secondary winding of the signal coupling transformer T1 output signal+ and signal- signals, respectively.

[0078] In this embodiment, the noise coupling circuit uses safety capacitor C2 and signal coupling transformer T1 to strip noise from the 50Hz AC power, generating signal+ and signal- signals.

[0079] The fifth embodiment of the present invention proposes a carrier communication network noise absorption system, and based on any of the above embodiments, the number of turns of the primary winding of the signal coupling transformer T1 is less than the number of turns of the secondary winding.

[0080] In this embodiment, the signal coupling transformer T1 adopts a turns ratio of 1:2 or 1:3, in which the number of turns in the primary winding is less than the number of turns in the secondary winding.

[0081] The sixth embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figure 4 As shown, the CENELEC-A bandpass filter is used to allow the center frequency of the CENELEC-A band to pass through better.

[0082] In this embodiment, the center frequency of 65kHz in the CENELEC-A band can be better filtered out, and its attenuation factor = (R42 + Z) L9 +Z C29 )||(Z) L10 +ZC30 ), where Z represents the impedance of each component; in a specific embodiment, the CENELEC-A bandpass filter attenuates the 30KHz frequency point by 8.9 times, the 60KHz frequency point by 6.7 times, and the 250KHz frequency point by 36 times.

[0083] The seventh embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figure 5 As shown, the FCC bandpass filter is used to allow the center frequency of the FCC band to pass through better.

[0084] In this embodiment, the center frequency of the FCC band at 300kHz can be better utilized, and its attenuation factor = (R33 + Z) L5 +Z C21 )||(Z) L7 +Z C23 ), where Z represents the impedance of each component; in a specific embodiment, the FCC bandpass filter attenuates the 30KHz frequency point by 38 times, the 60KHz frequency point by 17 times, and the 250KHz frequency point by 3 times.

[0085] The CENELEC-A bandpass filter and the FCC bandpass filter use the same circuit structure. The main difference is that they control the attenuation factor at different frequency points to make it easier for the center frequency of different frequency bands to pass through.

[0086] The eighth embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figure 6 As shown, the PLUS pulse signal generation circuit includes digital switches S1 and S2, comparator U100, MOSFETs Q101~Q109, and a voltage divider network; the voltage divider network includes resistors R100 and R101~R109.

[0087] The Vpp_CA and Vpp_FCC signals are connected to the first input terminal of comparator U100 through digital switches S1 and S2, respectively. MOSFETs Q101~Q109 are connected to resistors R101~R109 in a one-to-one correspondence. Each MOSFET is used to control the resistor connected to it to the voltage divider network. The resistor connected to the voltage divider network is divided by resistor R100 and outputs a reference voltage signal. The reference voltage signal is connected to the second input terminal of comparator U100. The output terminal of comparator U100 outputs a PLUS pulse signal.

[0088] In the comparator U100, the reference voltage signal is compared with Vpp_FCC or Vpp_CA, and the preleader SYNCP of the PLC signal packet is detected. Utilizing the SYNCP preleader as 10 groups of logic with equal amplitude and period, the comparator periodically triggers a high-level signal, thus generating a PLUS pulse signal. The typical data frame structure of the PLC signal is as follows: Figure 7 As shown.

[0089] Specifically, one end of resistor R100 is connected to a 15V voltage signal, resistors R101 to R109 are connected in series to ground, and the other end of resistor R100 is connected in parallel with resistor R101 to the second input terminal of comparator U100; the gates of MOSFETs Q101 to Q109 are connected to control signals Vref1 to 9 respectively, the sources are grounded respectively, and the drains are connected to their corresponding resistors respectively. When the MOSFETs are turned on, their corresponding resistors are connected to the voltage divider network.

[0090] The ninth embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figure 8 As shown, the noise absorption unit includes capacitors C41 and C42, diodes D41~D44, D46, and D47, rheostat D45, electrolytic capacitor EC41, resistors R41~R43, power resistors R44~R46, and field-effect transistors Q41~Q43.

[0091] The signal+ and signal- signals are connected to one end of capacitors C41 and C42, respectively.

[0092] The other end of capacitor C41 is connected to the positive terminal of diode D41, the negative terminal of diode D42, and one end of resistor R41, respectively. The positive terminal of diode D42 is grounded. The output signal V_REF+ of the PLC signal analysis unit is connected to the positive terminal of diode D46. The negative terminal of diode D46 is connected in parallel with the negative terminal of diode D41 to the noise signal V_Noise of the power line.

[0093] The other end of capacitor C42 is connected to the positive terminal of diode D43, the negative terminal of diode D44, and the other end of resistor R41, respectively. The negative terminal of diode D43 is connected to the noise signal V_Noise of the power line. The output signal V_REF- of the PLC signal analysis unit is connected to the positive terminal of diode D47, and the negative terminal of diode D47 is connected to ground in parallel with the positive terminal of diode D41.

[0094] The power line noise signal V_Noise is connected to ground after passing through electrolytic capacitor EC41. Rheostat D45 is connected in parallel across electrolytic capacitor EC41. One end of power resistor R44 is connected to the drain of MOSFET Q41. One end of power resistor R45 is connected to the drain of MOSFET Q42. One end of power resistor R46 is connected to the drain of MOSFET Q43.

[0095] The other end of power resistor R44, the other end of power resistor R45, the other end of power resistor R46, one end of resistor R42, and one end of resistor R43 are connected in parallel to the positive terminal of electrolytic capacitor EC41.

[0096] The source terminals of field-effect transistors Q41, Q42, and Q43, the other end of resistor R42, and the other end of resistor R43 are connected to ground in parallel.

[0097] The gates of field-effect transistors Q41, Q42, and Q43 are connected to the load control signals Load_1, Load_2, and Load_3, respectively.

[0098] In this embodiment, the noise from Signal+ and Signal- passes through capacitors C41 and C42. When the noise is a positive voltage and the signal is greater than V_REF+, the positive voltage of the noise passes through diodes D41 and D43 to V_Noise. When the noise is a negative voltage and the signal is less than V_REF-, the noise passes through diodes D43 and D44 to ground. V_Noise and ground (GND) are rectified into a DC voltage via EC41. Resistor R41 can dissipate the virtual current of the 50Hz AC.

[0099] Power resistors R44, R45, and R46 are 5Ω, TO-220 packaged, and can be fitted with heat sinks. Field-effect transistors Q41, Q42, and Q43 are controlled by the DSP module to absorb noise from different loads. The signal coupling transformer T1 in the noise and PLC signal coupling unit works as follows: If a 1:1 turns ratio transformer is used, field-effect transistor Q41 conducts, and power resistor R44 acts on V_Noise, equivalent to R44 acting entirely on the power line noise. However, if a transformer with a 1:2 or 1:3 turns ratio (e.g., primary winding smaller than secondary winding) is used, field-effect transistor Q41 conducts, and power resistor R44 acts on V_Noise, equivalent to 1 / 2 or 1 / 3 of the power resistor R44 acting on the power line noise. This allows for a heavier load on the noise, resulting in better noise absorption. The noise is generally white noise; with a fixed power, a heavier load results in a lower noise voltage amplitude. Meanwhile, the ADC module samples and monitors the V_Noise noise amplitude. When the noise amplitude is the same as the V_REF amplitude, it indicates that the signal amplitude and noise amplitude are the same in this state, and the signal-to-noise ratio is 0dB. At this time, the load is stopped.

[0100] OFDM can resolve signals with a signal-to-noise ratio of -6dB, at which point PLC signals can be correctly analyzed. Using the PLC signal analysis unit, V_Noise, Vpp_CA, Vdc_CA, and Vpp_FCC are analyzed by the DSP module. If no sudden change occurs within the set period, it indicates that noise persists, and the load should be maintained. If a sudden drop occurs, it indicates that the noise has weakened or disappeared, and the load should be reduced. If a sudden increase occurs, it indicates that the noise has increased, and the load should be increased.

[0101] The tenth embodiment of the present invention proposes a carrier communication network noise absorption system, and based on any of the above embodiments, the PLC signal analysis unit includes an ADC module, a DSP module and a DAC module;

[0102] The peak-to-peak value Vpp_CA of the noise in the CENELEC-A band and the rectified DC value Vdc_CA of the ADC module, and the peak-to-peak value Vpp_FCC of the noise in the FCC band and the rectified DC value Vdc_FCC of the ADC module.

[0103] The DSP module performs peak sampling analysis on the signal input to the ADC module;

[0104] Specifically, the DSP module performs OFDM digital analysis on the signal input to the ADC module, analyzing the PLC signal; it statistically determines whether the number of periodic peaks in the sampling results is the same as the number of periodic peak-to-peak voltage signals measured in the transformer, and records the signal peak value and / or root mean square value; the peak value and / or root mean square value are input to the DAC module, which outputs voltage signals V_REF+ and VREF-. If they are the same, the signal input to the ADC module is determined to be a PLC signal; if they are different, the signal input to the ADC module is determined to be noisy, and Q41, Q42, and Q43 in the noise absorption unit are controlled to apply power resistors to the noise source of the power line to absorb the noise until the number of periodic peaks in the sampling results is the same as the number of periodic peak-to-peak voltage signals measured in the transformer.

[0105] In some embodiments, the DSP module also receives a PLUS pulse signal, such as Figure 9 As shown, if the noise signal is complex and the PLC signal amplitude is lower than the noise, resulting in a negative signal-to-noise ratio, the PLC signal is submerged in the noise, causing the DSP to fail to perform OFDM digital analysis. In this case, the DSP analyzes the analog signal and detects the PLUS pulse signal, counting the high-level pulses. If the PLUS pulse signal records 10 equal-period high-level pulses, the current signal is considered a valid PLC signal. If there is random noise and 10 equal-period high-level pulses cannot be detected, the noise signal is determined to be greater than the PLC signal. The Q41, Q42, and Q43 in the noise absorption unit are controlled to apply the power resistor to the noise source on the power line to absorb the noise.

[0106] In this embodiment, Vpp_CA, Vdc_CA, Vpp_FCC, and Vdc_FCC are input to the ADC module for sampling, and the DSP module analyzes them. The known communication frequency band is composed of narrowband PLC data packets. The measurement packet header is a fixed data preamble, consisting of 10 voltage signals with equal periods and equal peak-to-peak values. Peak sampling is performed; if 10 equal-period peaks are found, they are identified as PLC signals, and the peak value and RMS value are recorded. The peak or RMS value is input to the DAC module, which outputs voltages V_REF+ and VREF-. When the noise amplitude is greater than the PLC signal amplitude, the 10 equal-period peaks cannot be measured. In this case, the field-effect transistors Q41, Q42, and Q43 in the noise absorption unit are enabled sequentially, applying a power resistor to the noise source to absorb the noise. When the noise amplitude is less than the PLC signal amplitude, the 10 equal-period peaks can be measured. This achieves noise absorption, improves the signal-to-noise ratio, and increases the communication success rate. The noise absorption process of the carrier communication network noise absorption system is as follows: Figure 10As shown, it can be seen that initially the noise amplitude is higher than the PLC signal, thus overwhelming the PLC signal. Then, after the carrier communication network noise system starts working, the noise is absorbed, making the PLC signal amplitude higher than the noise, which facilitates PLC signal analysis. Finally, when the carrier communication network noise system is turned off, the signal-to-noise ratio returns to its original state. Figure 11 The diagram shows the detailed time-domain waveforms of noise and PLC signals during the operation of a carrier communication network noise system.

[0107] The eleventh embodiment of the present invention proposes a carrier communication network noise absorption system, and based on any of the above embodiments, the PLC signal analysis unit is provided with an LED indicator light, which is used to indicate the strength of the noise. The stronger the noise, the faster the LED light flashes.

[0108] The twelfth embodiment of the present invention proposes a noise absorption system for a carrier communication network, and based on any of the above embodiments, such as... Figures 12 to 14 As shown, the external dimensions of the noise absorber 1, which comprises the entire system, are as follows: Figure 12 It can be portablely installed on meters that meet BS or DIN terminal requirements. Figure 13 To fix the noise absorber 1, when installation is required, remove the screws from the original terminal 2 of the electricity meter, use the screws 11 of the noise absorber 1 to connect to the original terminal 2 of the electricity meter, and press it to the power line. The connection with the power line is achieved through the screws 11. The screws 11 and the PCB board 12 are connected by springs 13 to provide a power circuit for the entire noise absorption circuit. Figure 14 Internal structure of the noise absorber.

[0109] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention shall be included within the scope of protection of this invention.

Claims

1. A noise absorption system for a carrier communication network, characterized in that, include: The power supply unit is used to supply power to the system. The noise and PLC signal coupling unit is connected to the power line. It uses a coupling capacitor and coupling transformer circuit to filter the noise and PLC signal in the power line and output the noise and PLC signal. At the same time, it generates a PLUS pulse signal based on the preamble characteristics of the PLC signal packet to reflect whether the signal in the power line is a valid PLC signal. The noise absorption unit, connected to the noise and PLC signal coupling unit, uses RC and MOS control circuits to apply different loads to the noise source on the power line, so that the noise energy is converted into heat energy, reducing the noise voltage amplitude and absorbing the noise voltage amplitude to be equal to or lower than the PLC signal amplitude. The PLC signal analysis unit is connected to the noise and PLC signal coupling unit and the noise absorption unit, respectively. After sampling the noise and PLC signal ADC output from the noise and PLC signal coupling unit, it sends the data to the DSP for OFDM modulation analysis to determine whether the current signal is a PLC signal or a noise signal. If the current signal is a PLC signal, it indicates that the current state of the noise absorption circuit is reasonable. If the current signal is not a PLC signal, it controls the noise absorption unit to absorb noise until the current signal is a PLC signal. When OFDM modulation analysis fails, the PLC signal analysis unit analyzes the noise and the PLUS pulse signal output by the PLC signal coupling unit to determine whether the signal in the power line is a valid PLC signal. If the current signal is a valid PLC signal, it indicates that the current state of the noise absorption circuit is reasonable. If the current signal is not a valid PLC signal, the noise absorption unit is controlled to absorb noise until the current signal is a valid PLC signal.

2. The carrier communication network noise absorption system according to claim 1, characterized in that, The power supply unit includes a varistor VR1, a wire-wound power resistor R15, a high-voltage safety capacitor C9, a high-voltage rectifier diodes D8~D11, TVS diodes Z1 and Z2, electrolytic capacitors EC2 and EC3, and an LDO linear regulator U1. The varistor VR1 is connected between the neutral and live wires; one end of the wire-wound power resistor R15 is connected to the input terminal of the live wire and one end of the varistor VR1, and the other end of the wire-wound power resistor R15 is connected to one end of the high-voltage safety capacitor C9. The other end of the high-voltage safety capacitor C9 is connected between the high-voltage rectifier diodes D9 and D11. The input terminal of the neutral wire is connected between the high-voltage rectifier diodes D8 and D10. The negative terminals of the high-voltage rectifier diodes D8 and D9 are connected, and the positive terminals of D10 and D11 are connected. The high-voltage rectifier diodes D8 to D11 form a rectifier bridge. TVS diodes Z1 and Z2 are connected in parallel between the two output terminals of the rectifier bridge. Electrolytic capacitors EC2 and EC3 are connected in parallel across the two ends of TVS diode Z2. The positive terminal of electrolytic capacitor EC3 is connected to the input terminal of the LDO linear regulator U1, and the output terminal of the LDO linear regulator U1 supplies power to the system.

3. The carrier communication network noise absorption system according to claim 1, characterized in that, The noise and PLC signal coupling unit includes a noise coupling circuit, a CENELEC-A bandpass filter, an FCC bandpass filter, and a PLUS pulse signal generation circuit. The input of the noise coupling circuit is connected to a power line, and its output is connected to the inputs of both the CENELEC-A and FCC bandpass filters. The output of the CENELEC-A bandpass filter is the peak-to-peak value Vpp_CA of the CENELEC-A band noise and the rectified DC value Vdc_CA. The output of the FCC bandpass filter is the peak-to-peak value Vpp_FCC of the FCC band noise and the rectified DC value Vdc_FCC. The input of the PLUS pulse signal generation circuit receives the Vpp_CA and Vpp_FCC signals and compares them with a reference voltage signal to output a PLUS pulse signal.

4. A carrier communication network noise absorption system according to claim 3, characterized in that, The noise coupling circuit includes a safety capacitor C2, a wound power inductor L4, and a signal coupling transformer T1. The live wire of the power line is connected to one end of the safety capacitor C2, and the other end of the safety capacitor C2 is connected to one end of the wound power inductor L4. The other end of the wound power inductor L4 is connected to the same-name terminal of the primary winding of the signal coupling transformer T1, and the neutral wire of the power line is connected to the opposite-name terminal of the primary winding of the signal coupling transformer T1. The same-name terminal and the opposite-name terminal of the secondary winding of the signal coupling transformer T1 output signal+ and signal- signals, respectively.

5. A carrier communication network noise absorption system according to claim 4, characterized in that, The number of turns in the primary winding of the signal coupling transformer T1 is less than the number of turns in the secondary winding.

6. A carrier communication network noise absorption system according to claim 3, characterized in that, The CENELEC-A bandpass filter is used to allow the center frequency of the CENELEC-A band to pass through more effectively.

7. A carrier communication network noise absorption system according to claim 3, characterized in that, The FCC bandpass filter is used to allow the center frequency of the FCC band to pass through better.

8. A carrier communication network noise absorption system according to claim 4, characterized in that, The PLUS pulse signal generation circuit includes digital switches S1 and S2, comparator U100, MOSFETs Q101~Q109, and a voltage divider network; the voltage divider network includes resistors R100 and R101~R109. The Vpp_CA and Vpp_FCC signals are connected to the first input terminal of comparator U100 through digital switches S1 and S2, respectively. MOSFETs Q101~Q109 are connected to resistors R101~R109 in a one-to-one correspondence. Each MOSFET is used to control the resistor connected to it to the voltage divider network. The resistor connected to the voltage divider network is divided by resistor R100 and outputs a reference voltage signal. The reference voltage signal is connected to the second input terminal of comparator U100. The output terminal of comparator U100 outputs a PLUS pulse signal. In the comparator U100, the reference voltage signal is compared with Vpp_FCC or Vpp_CA, the prelead wave SYNCP of the PLC signal packet is detected, and the comparator is triggered to output a high-level signal with equal amplitude and period using 10 sets of logic with equal amplitude and period of the prelead wave SYNCP, thus generating the PLUS pulse signal.

9. A carrier communication network noise absorption system according to claim 8, characterized in that, The noise absorption unit includes capacitors C41 and C42, diodes D41~D44, D46, and D47, a variable resistor D45, an electrolytic capacitor EC41, resistors R41~R43, power resistors R44~R46, and field-effect transistors Q41~Q43. The signal+ and signal- signals are connected to one end of capacitors C41 and C42, respectively. The other end of capacitor C41 is connected to the positive terminal of diode D41, the negative terminal of diode D42, and one end of resistor R41, respectively. The positive terminal of diode D42 is grounded. The output signal V_REF+ of the PLC signal analysis unit is connected to the positive terminal of diode D46. The negative terminal of diode D46 is connected in parallel with the negative terminal of diode D41 and connected to the noise signal V_Noise of the power line. The other end of capacitor C42 is connected to the positive terminal of diode D43, the negative terminal of diode D44, and the other end of resistor R41, respectively. The negative terminal of diode D43 is connected to the noise signal V_Noise of the power line. The output signal V_REF- of the PLC signal analysis unit is connected to the positive terminal of diode D47, and the negative terminal of diode D47 is connected to ground in parallel with the positive terminal of diode D41. The power line noise signal V_Noise is connected to ground after passing through electrolytic capacitor EC41. Rheostat D45 is connected in parallel across electrolytic capacitor EC41. One end of power resistor R44 is connected to the drain of MOSFET Q41. One end of power resistor R45 is connected to the drain of MOSFET Q42. One end of power resistor R46 is connected to the drain of MOSFET Q43. The other end of power resistor R44, the other end of power resistor R45, the other end of power resistor R46, one end of resistor R42, and one end of resistor R43 are connected in parallel to the positive terminal of electrolytic capacitor EC41. The source terminals of field-effect transistors Q41, Q42, and Q43, the other end of resistor R42, and the other end of resistor R43 are connected to ground in parallel. The gates of field-effect transistors Q41, Q42, and Q43 are connected to the load control signals Load_1, Load_2, and Load_3, respectively.

10. A carrier communication network noise absorption system according to claim 9, characterized in that, The PLC signal analysis unit includes an ADC module, a DSP module, and a DAC module; The peak-to-peak value Vpp_CA of the noise in the CENELEC-A band and the rectified DC value Vdc_CA of the ADC module, and the peak-to-peak value Vpp_FCC of the noise in the FCC band and the rectified DC value Vdc_FCC of the ADC module. The DSP module performs OFDM digital analysis on the signals input to the ADC module and analyzes the PLC signals; Statistically determine whether the number of periodic peaks in the sampling results is the same as the number of periodic peak-to-peak voltage signals measured in the package head, and record the signal peak value and / or root mean square value; input the peak value and / or root mean square value into the DAC module, and the DAC module outputs voltage signals V_REF+ and VREF-; If they are the same, it is determined that the signal connected to the ADC module is a PLC signal; if they are different, it is determined that the signal connected to the ADC module is noisy. Then, Q41, Q42, and Q43 in the noise absorption unit are controlled to apply the power resistor to the noise source of the power line to absorb the noise until the number of equal periodic peaks in the sampling result is the same as the number of equal periodic peak-to-peak voltage signals in the measured package. If the noise signal is complex, causing the DSP to fail to perform OFDM digital analysis, the DSP will analyze the analog signal. The DSP will detect the PLUS pulse signal and count the high levels. If the PLUS pulse signal records 10 equal-period high-level pulses, the current signal is considered a valid PLC signal. If 10 equal-period high-level pulses cannot be detected, it is determined that the noise signal is greater than the PLC signal. The DSP will then control Q41, Q42, and Q43 in the noise absorption unit to apply power resistors to the noise source on the power line to absorb the noise.

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