Carrier coupling circuitTechnical Field
The invention relates to the technical field of power carrier communication, in particular to a carrier coupling circuit.
Background
A carrier coupling circuit is a circuit design for a power line communication or similar communication system that allows signals to be transmitted and received over a power line or other transmission medium. In a carrier coupling circuit, the signal is transmitted in the form of a high-frequency carrier wave, and the actual communication data is modulated onto this carrier wave. In the power line communication system, electricity consumption management equipment collects and transmits electricity consumption data to centralized acquisition equipment through a carrier coupling circuit, and receives control commands from user communication equipment; the centralized acquisition equipment is responsible for summarizing and processing the data, uploading the data to a higher-layer management system, and simultaneously issuing instructions to the electricity management equipment; the user communication equipment allows the user to monitor and control the electricity consumption environment and realize the interaction with the electricity consumption management equipment, and all the communication is completed on the power line through the shared carrier coupling circuit.
The uplink and downlink channels of the prior art carrier coupling circuit share the same set of windings of the coupler T. The uplink channel is used for collecting a large amount of data in a centralized manner and is generally regarded as a key channel. The coupler T and the isolation capacitor CA of the power utilization management equipment form an uplink coupling channel, the carrier transceiving circuit generates a signal, and the signal is coupled to the 3-4 winding of the coupler T through the 1-2 winding of the coupler T and then is transmitted to the phase A and the zero line of the mains supply through the isolation capacitor CA. And the coupling channel of the centralized acquisition equipment receives signals sent by the power utilization management equipment from the phase A and the zero line of the commercial power to obtain signals. And vice versa. The downlink channel, which is used for single point low frequency data communication, is generally considered as a secondary channel. The coupler T and the isolation capacitor CA-of the electricity management equipment form a downlink coupling channel, the carrier receiving and transmitting circuit generates signals, the signals are coupled to the 3-4 windings of the coupler T through the 1-2 windings of the coupler T, and then the signals are transmitted to the rear pole of the commercial power A successive apparatus through the isolation capacitor CA-. And the coupling channel of the user communication equipment receives signals sent by the power utilization management equipment from the relay and the zero line to obtain signals. And vice versa. In the prior art, circuit parameters of an uplink channel are unstable, and when a relay is opened and closed, the capacitance value of a series capacitor is changed, so that the circuit parameters can be greatly changed, the central frequency point of a coupling circuit bandpass is changed, the frequency of a carrier signal is not matched, and the communication sensitivity is affected.
This solution has some obvious drawbacks: the centralized acquisition equipment and the electricity management equipment communicate, because the uplink and the downlink channels share the same group of coils of the coupler T, when the relay is disconnected, the signal which only passes through the uplink channel can be split by a mixed circuit consisting of the coupling channel of the user communication equipment, the isolation capacitor CA-and the relay, and the signal which only passes through the downlink channel can also be split by the mixed circuit consisting of the isolation capacitor CA and the coupling channel of the centralized acquisition equipment. That is, when the relay is turned off, the signals are split in the hybrid circuit, so that the signals which should be unidirectionally transmitted interfere with each other, thereby reducing the effective signal strength and affecting the reliability of communication.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention provides a carrier coupling circuit, which is used for reducing apparent power consumption and realizing frequency parameter matching by introducing a compensation inductance, and simultaneously, an uplink channel and a downlink channel of an electricity management device respectively use two independent coupler windings, so that the two channels are completely independent, and mutual noninterference between the uplink channel and the downlink channel is realized.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
A carrier coupling circuit comprises an uplink channel and a downlink channel which are connected in parallel;
The uplink channel comprises a winding I, a compensating inductance I and an isolating capacitor I which are sequentially connected in series; the downlink channel comprises a second winding, a second compensating inductor and a second isolating capacitor which are sequentially connected in series; the first winding and the second winding are two different windings of the first coupler; and the isolation capacitor II is connected with the relay I in series.
The compensating inductor is an inductance element and has the main function of being matched with a capacitor to form an LC filter, so that reactive power in a circuit is reduced, apparent power consumption is reduced, and the power factor of the circuit is improved. By adding the compensation inductance, the circuit can work at a specific frequency, and frequency parameter matching is realized. The compensating inductor is also used for filtering out unwanted high-frequency noise and interference and guaranteeing clear transmission of carrier signals.
And the uplink channel is used for carrying out signal communication between the electricity management equipment and the centralized acquisition equipment. The carrier transceiver circuit is used for generating signals. The carrier transceiver circuit of the electricity management equipment generates a signal, and the signal is transmitted to a winding I of the coupler I through coupling of the coupler I and then transmitted to a phase A and a zero line of the mains supply through a compensating inductor I and an isolating capacitor I. The centralized acquisition equipment receives signals sent by the electricity management equipment from the phase A and the zero line of the commercial power through a coupling channel to obtain signals. And vice versa.
And the downlink channel is used for carrying out signal communication between the electricity management equipment and the user communication equipment. The carrier transceiver circuit of the electricity management equipment generates a signal, and the signal is transmitted to a winding II of the coupler I through coupling of the coupler I and then transmitted to a rear pole of the relay I, a phase A of the mains supply and a zero line through a compensation inductor II and an isolation capacitor II. The user communication equipment receives the signal sent by the electricity management equipment through the rear pole and the zero line of the coupling channel relay I, and the signal is obtained. And vice versa.
In summary, through the first winding and the second winding of the physical isolation coupler, when the centralized collection device and the electricity management device communicate, even if the first relay is disconnected, the uplink signal can only be transmitted through the uplink channel formed by the first winding of the coupler, the first compensation inductor and the first isolation capacitor, and the downlink signal can only be transmitted through the downlink channel formed by the second winding of the coupler, the second compensation inductor and the second isolation capacitor, so that the signal can not be split, and the signal integrity is ensured.
Preferably, the uplink channel further comprises a first coupling channel for carrying out signal communication between the centralized acquisition equipment and the electricity management equipment; the first coupling channel is connected with a carrier transceiving circuit of the centralized acquisition equipment; the first coupling channel comprises a second coupler, a third compensation inductor and a third isolation capacitor which are sequentially connected in series.
The signal of the uplink channel is transmitted to the phase A and the zero line of the commercial power, and the centralized acquisition equipment receives the signal sent by the power consumption management equipment from the phase A and the zero line of the commercial power through a coupling channel I consisting of a coupler II, a compensating inductor III and an isolating capacitor III which are sequentially connected in series, so as to obtain the signal. The centralized acquisition equipment extracts signals from the phase A and the zero line of the mains supply through a first coupling channel. The second coupler transmits the signal on the power line to the centralized acquisition device while providing the necessary isolation. The compensation inductance three and the isolation capacitance three ensure that the signal remains as intact as possible during reception. The second coupler can provide signal isolation, and interference to a power grid is reduced. The compensation inductance III is used as an inductive impedance for compensating the power line, and is beneficial to improving the efficiency of signal transmission. The isolation capacitor is used to isolate the DC component, allowing high frequency signals to pass while preventing DC current from passing through the coupler.
Preferably, the downlink channel further includes a second coupling channel for signal communication between the user communication device and the power consumption management device; the second coupling channel is connected with a carrier transceiving circuit of the user communication equipment; the second coupling channel comprises a third coupler, a fourth compensating inductor and a fourth isolating capacitor which are sequentially connected in series.
After the signal of the downlink channel is transmitted to the rear pole of the first relay, the phase A of the commercial power and the zero line, the user communication equipment receives the signal sent by the power management equipment through the coupling channel II consisting of the coupler III, the compensating inductor IV and the isolating capacitor IV which are sequentially connected in series, and the rear pole of the first relay and the zero line to obtain the signal. And vice versa.
Preferably, a relay II is connected in series between the coupling channel II and the zero line.
The relay I and the relay II are used for allowing or preventing the power management equipment from powering on the subsequent loads of the relay I and the relay II by controlling the on/off of the relay I and the relay II, but not influencing the information communication between the power management equipment and the user communication equipment. Taking electricity meters as an example, when a resident defaults or a specified event occurs, the relay one and the relay two are disconnected, and the resident is powered off. At this time, the resident can use the domestic display unit CIU to send charging information to the ammeter through the downlink channel, and the first relay and the second relay are closed after fully pay electric charges or event elimination, so that the resident can be electrified again.
Preferably, the uplink channel includes three parallel coupling channels one, and is respectively connected in series with a mains supply a phase, a mains supply B phase, and a mains supply C phase.
The coupling channel I is connected to the three-phase power line, so that signals can be transmitted between the three phases simultaneously or respectively, and the transmission capacity of the signals and the reliability of the system are improved. If the signal transmission of one phase is disturbed or fails, the other phases can still work normally, thereby providing a redundancy mechanism and increasing the fault tolerance of the system. Distributing the signal transmission among the three phases can balance the load on the power line, reducing the risk of single phase overload.
Preferably, the downlink channel further comprises an LC filter connected in series with one end of the winding two; the number of the LC filters is three, and the LC filters are respectively connected with a commercial power A phase, a commercial power B phase and a commercial power C; three LC filters are connected in parallel; the LC filter comprises a compensation inductance II and an isolation capacitance II; each LC filter is connected in series with one of the relays one.
By providing LC filters in parallel on the a, B and C phases of the mains respectively, each LC filter can be connected to one subscriber communication device, allowing simultaneous access to a plurality of subscriber communication devices. Each LC filter may be independently connected to a user communication device so that the system can support simultaneous communication for multiple users.
Preferably, both the upstream channel and the downstream channel are provided with a transient voltage suppressor.
The transient voltage suppressor can respond and conduct in a very short time, so that the transient overvoltage is clamped at a safe level, the electronic equipment is protected from voltage spike damage caused by power line faults, lightning strokes or other electrical disturbances, and the stability and the reliability of a circuit are ensured. Transient voltage suppressors are typically composed of one or more zener diodes designed to conduct at a specific trigger voltage. When the voltage exceeds this trigger point, the transient voltage suppressor will quickly transition from a high impedance state to a low impedance state, allowing a significant amount of current to flow, thereby suppressing the rise in voltage and protecting the following circuits.
Preferably, windings of the uplink channel and the downlink channel are connected in parallel with one transient voltage suppressor.
The transient voltage suppressor is capable of rapidly responding and limiting voltage spikes, protecting windings in the coupler from transient overvoltages, and thereby prolonging the service life of the device. Meanwhile, by suppressing voltage spikes, the transient voltage suppressor helps to maintain stable operation of the power line communication system and reduce communication interruption caused by voltage fluctuation. In a power line communication system, a winding parallel transient voltage suppressor for an uplink channel and a downlink channel is an effective protection measure, and is helpful for ensuring stable operation and long-term reliability of the system.
Compared with the prior art, the invention has the beneficial effects that:
1. because the design of the coupler and the compensating inductance is adopted, the uplink channel and the downlink channel are mutually independent, no physical connection exists, the noises are not influenced mutually, the transmission of the noises is blocked, and the signal to noise ratio is improved. And the signal transmission is not affected by the relay, which means that even if the relay is disconnected, the signal can still be normally transmitted, and the signal can not be shunted, so that the signal integrity is ensured.
2. By introducing the compensating inductance, apparent power consumption is reduced, and frequency parameter matching is realized. By adding the inductance, the capacitance of the isolation capacitor can be inversely proportional reduced without changing the design of the coupler under the condition of realizing the same resonant frequency, namely, the capacitance can be selected to be smaller, and the smaller the capacitance is, the smaller the power consumption is.
3. The design that zero line and relay two are established ties is adopted for user communication equipment gets electricity from relay one back pole and relay two back poles, no matter the relay is opened or closed, can communicate through the coupling channel and the power consumption management equipment that isolation capacitance two, compensation inductance two, winding two are constituteed, need not increase extra circuit any more.
4. The coupling channel I formed by the coupler II, the compensating inductor III and the isolating capacitor III is adopted, so that the impedance matching of a power line is optimized, the signal reflection and loss are reduced, and the transmission efficiency is improved. Meanwhile, the second coupler and the third isolation capacitor provide signal isolation, so that the influence of noise and interference in a power grid on signal transmission is reduced, and the safety of equipment and users is protected.
5. Since the coupling channels of the centralized acquisition device are connected to the three-phase power line, it is possible to reduce communication interruption due to interference on a certain phase. The simultaneous use of three-phase lines may increase the available bandwidth, allow more signals to be transmitted simultaneously, and splitting signals among the three phases may reduce signal attenuation and distortion, thereby improving signal quality.
6. The circuit parameters of the uplink channel are stable, the capacitance value of the series capacitor of the relay is unchanged all the time no matter the relay is opened or closed, the center frequency point of the coupling circuit bandpass is kept stable, the coupling circuit bandpass can be consistent with the carrier frequency all the time, and the communication sensitivity is high.
Drawings
FIG. 1 is a circuit diagram of embodiment 1;
FIG. 2 is a circuit diagram of embodiment 2;
Wherein:
T2, coupler I; t4, a second coupler; t5, a coupler III;
T21, winding one; t22, winding II;
L1, compensating inductance I; l2, compensating the second inductance; l4, compensating inductance III; l5, compensating inductance IV;
c1, isolating a first capacitor; c2, isolating the second capacitor; c4, an isolation capacitor III; c5, an isolation capacitor IV;
k1, relay I; and K2, a relay II.
Detailed Description
The invention will be further described with reference to the specific drawings in order to make the technical means, the inventive features, the achievement of the purpose and the effect of the implementation of the invention easily understood. The present invention is not limited to the following examples.
It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that it can be practiced, since modifications, changes in the proportions, or otherwise, used in the practice of the invention, are not intended to be critical to the essential characteristics of the invention, but are otherwise, required to achieve the objective and effect taught by the invention.
Example 1:
A carrier coupling circuit as shown in fig. 1 includes an upstream channel and a downstream channel connected in parallel. The invention can be used in single-phase two-wire split type double-relay ammeter and collector, in particular, the electricity management equipment is the single-phase two-wire split type double-relay ammeter, the user communication equipment is a household display unit CIU (the household display unit CIU is a component in an intelligent ammeter system and is mainly used in families to provide an interactive interface between a user and an electric energy meter), and the centralized collection equipment is a concentrator.
The uplink channel comprises a winding I T21, a compensating inductor I L1 and an isolating capacitor I C1 which are sequentially connected in series; the system also comprises a first coupling channel connected with the carrier transceiving circuit of the centralized acquisition equipment; the first coupling channel is used for carrying out signal communication between the concentrator and the single-phase two-wire split type double-relay ammeter. The first coupling channel comprises a second coupler T4, a compensating inductor tri L4 and an isolating capacitor tri C4 which are sequentially connected in series. The compensation inductor L1 is matched with the isolation capacitor C1 to form a band-pass filter in the LC filter, and the capacity of the isolation capacitor 1C1 can be reduced by adding the compensation inductor L1, so that reactive power in a circuit is reduced, apparent power consumption is reduced, and the power factor of the circuit is improved. Meanwhile, the circuit can work under specific frequency, frequency parameter matching is realized, unnecessary high-frequency noise and interference are filtered, and clear transmission of carrier signals is ensured.
The carrier receiving and transmitting circuit is used for modulating and demodulating signals, the transmitting circuit loads carrier information on the power line, and the receiving circuit restores the carrier signal on the power line into an original signal. The carrier transceiver circuit is also used for sending out the modulated signal through a power line so as to realize remote transmission of data, receiving the signal from the power line and processing the signal.
The concentrator is used for carrying out centralized collection on data such as electric quantity, load and event of the electric meter through an uplink channel, and also carrying out parameter setting and relay opening and closing operation on the electric meter through the uplink channel. One concentrator may correspond to multiple meters simultaneously. The carrier transceiving circuit of the single-phase two-wire split type double-relay ammeter generates a signal, and the signal is transmitted to a winding I T21 of a coupler I T2 through coupling of the coupler I T2 and then transmitted to a phase A and a zero line of mains supply through a compensating inductor I L1 and an isolating capacitor I C1. The concentrator receives signals sent by the single-phase two-wire split type double-relay ammeter from the A phase and the zero line of the commercial power through a coupling channel to obtain signals.
The downlink channel comprises a winding II T22, a compensating inductor II L2 and an isolating capacitor II C2 which are sequentially connected in series; winding one T21 and winding two T22 are two different windings of coupler one T2. The downlink channel also comprises a second coupling channel connected with the carrier receiving and transmitting circuit of the user communication equipment; the second coupling channel is used for carrying out signal communication between the household display unit CIU and the single-phase two-wire split type double-relay ammeter. The second coupling channel comprises a coupler III T5, a compensation inductor IV L5 and an isolation capacitor IV C5 which are sequentially connected in series. The household display unit CIU carries out electric charge recharging through a downlink channel, and can also check electricity consumption data recorded by the ammeter through the downlink channel. After a signal sent by the single-phase two-wire split double-relay ammeter is transmitted to the rear pole of the first K1 relay, the phase A of the commercial power and the zero wire, the household display unit CIU receives the signal sent by the single-phase two-wire split double-relay ammeter through a coupling channel II consisting of a coupler III T5, a compensation inductor IV L5 and an isolation capacitor IV C5 which are sequentially connected in series, and the rear pole of the first K1 relay and the zero wire to obtain the signal.
Through the first T21 of winding of physical isolation coupler T2 and second T22 of winding, when concentrator and two split type double relay ammeter of single-phase two lines communicate, even relay K1 breaks off, the ascending signal can only pass through the ascending channel transmission that the winding of coupler T2 constitutes first T21, compensating inductance L1, isolating capacitor C1, and the descending signal can only pass through the descending channel transmission that the winding of coupler T2 constitutes second T22, compensating inductance L2, isolating capacitor C2, can not shunted, ensure signal integrity. When the relay is closed, the parameters of the band-pass filter of the uplink channel are not changed, the center frequency point is kept stable, and the sensitivity is not affected.
And a relay II K2 is connected in series between the coupling channel II and the zero line. When the resident user defaults or a specified event occurs, the first relay K1 and the second relay K2 are disconnected, or the second relay K2 is not configured, and the resident is powered off. At this time, the resident can use the home display unit CIU to send charging information to the electricity meter through the downlink channel, fully pay the electric charge or close the relay after the event is eliminated, and the resident is powered on again.
All windings of the uplink and downlink channels are connected in parallel with a transient voltage suppressor. The transient voltage suppressor can respond and conduct in a very short time, so that the transient overvoltage is clamped at a safe level, the electronic equipment is protected from voltage spike damage caused by power line faults, lightning strokes or other electrical disturbances, and the stability and the reliability of a circuit are ensured. Transient voltage suppressors are typically composed of one or more zener diodes designed to conduct at a specific trigger voltage. When the voltage exceeds this trigger point, the transient voltage suppressor will quickly transition from a high impedance state to a low impedance state, allowing a significant amount of current to flow, thereby suppressing the rise in voltage and protecting the following circuits. The transient voltage suppressor is capable of rapidly responding and limiting voltage spikes, protecting windings in the coupler from transient overvoltages, and thereby prolonging the service life of the device. Meanwhile, by suppressing voltage spikes, the transient voltage suppressor helps to maintain stable operation of the power line communication system and reduce communication interruption caused by voltage fluctuation. In a power line communication system, a winding parallel transient voltage suppressor for an uplink channel and a downlink channel is an effective protection measure, and is helpful for ensuring stable operation and long-term reliability of the system.
Example 2:
as shown in fig. 2, the embodiment is a three-phase four-wire split type intelligent ammeter and a collector. The difference between the embodiment and the embodiment 1 is that the embodiment has three parallel coupling channels one and an LC filter, and the electric meter is a three-phase four-wire split type intelligent electric meter. The uplink channel of the embodiment comprises three parallel coupling channels I, one ends of the three coupling channels I are respectively connected with a mains supply A phase, a mains supply B phase and a mains supply C phase in series, and the other ends of the three coupling channels I are connected with a zero line, so that the three-phase four-wire split intelligent ammeter is connected with the mains supply A phase, the mains supply B phase, the mains supply C phase and the zero line. The first coupling channels are connected with a carrier transceiving circuit. The first coupling channel comprises a second coupler T4, a compensating inductor tri L4 and an isolating capacitor tri C4 which are sequentially connected in series.
The downlink channel also comprises an LC filter connected with one end of the winding II T22 in series; the number of the LC filters is three, and the LC filters are respectively connected with a commercial power A phase, a commercial power B phase and a commercial power C; the three LC filters are connected in parallel; the LC filter comprises a compensation inductance II L2 and an isolation capacitor II C2; each LC filter is connected in series with a relay, K1. By providing parallel LC filters on the a, B and C phases of the mains respectively, each LC filter can be connected to one home display unit CIU, allowing simultaneous access to a plurality of home display units CIU, each LC filter can be connected independently to one home display unit CIU.
The invention solves the problem of signal shunt caused by the same group of windings of the coupler shared by the uplink channel and the downlink channel, so that when the relay K1 is disconnected, the signal which only passes through the uplink channel cannot be shunted by a mixed circuit consisting of the downlink channel capacitor, the relay and the coupler of the user communication equipment, and the signal which only passes through the downlink channel cannot be shunted by the mixed circuit consisting of the uplink channel capacitor and the coupler of the centralized acquisition equipment, thereby preventing the effective signal from being reduced due to signal shunt and affecting the communication reliability.
The carrier coupling circuit in the prior art has large power consumption and difficult parameter adjustment, and the inductance of the coupler cannot be effectively adjusted due to the fact that the influence of the inductance is not large, so that the capacitance selection value of each capacitor is large, and the larger the capacitance is, the larger the apparent power consumption of the whole circuit is, and the limit value requirement of the product standard can be exceeded. According to the invention, the first winding T21 and the second winding T22 are two different windings of the first coupler T2, the volumes of the first winding T21 and the second winding T22 can be relatively reduced, the inductance can be reduced due to the volume influence of the windings, the capacitance selection value of each capacitor is small, and the apparent power consumption of the whole circuit is smaller.
The carrier coupling circuit in the prior art has the mutual influence of noise, and the noise is mutually coupled on an uplink channel and a downlink channel through a capacitor connected with a winding of a coupler of the power consumption management equipment, so that the success rate of signal transmission is seriously influenced. The invention enables the uplink channel and the downlink channel to be separated independently, and when the relay is closed, noise cannot be coupled with each other on the uplink channel and the downlink channel, thereby improving the success rate of signal transmission.
In the carrier coupling circuit in the prior art, the circuit parameters of the uplink channel are unstable. In the electricity management equipment, when the relay is disconnected, the capacitance value of the series capacitor is the capacitance value of an uplink channel, and when the relay is closed, the capacitance value of the series capacitor is the sum of the capacitance value of the uplink channel and the capacitance value of a downlink channel, and circuit parameters can change greatly, so that the central frequency point of a coupling circuit bandpass is changed, the frequency of a carrier signal is not matched, and the communication sensitivity is affected. The invention ensures that the capacitance value of the uplink channel is unchanged all the time through the independent uplink channel and the downlink channel, so that the circuit parameters are not changed greatly and the communication sensitivity is not affected.
The carrier coupling circuit in the prior art has potential safety hazards, and after the relay is disconnected, the power management equipment is completely powered off, but a complete alternating current loop is formed among the uplink channel capacitance, the downlink channel capacitance of the power management equipment, the capacitance of the user communication equipment and the coupler, so that the leakage risk exists. According to the invention, through the design of the two relays and the independent uplink channel and downlink channel, each electronic element of the uplink channel and the downlink channel can not form a complete power-on loop when the relays are disconnected, so that the leakage risk is avoided.