RU2288507C1 - Method for generation of resulting series of synchronization impulses during transfer of information by means of code messages along alternating-current electric network - Google Patents

Abstract

FIELD: technology for transferring information via electric supply lines, possible use in alarm signaling systems.

SUBSTANCE: in phases of alternating-current electric network selected for transferring code messages, moments of transfer of main harmonic of network voltage over zero are determined with derivative of same sign and time stamps are generated in these moments. In moments of beginning of said stamps synchronization impulses are generated. Exchange of symbolic information is realized between phases of electric network selected for transferring code messages. Resulting series of synchronization impulses is received, providing transport function for transferring information in unified communication network. Exchange of symbolic information between phases of electric network is realized with usage of receiving-transmitting device, made with possible receipt and/or transmission of code messages via phases of alternating-current electric network, or using identical reactive connecting devices.

EFFECT: simplified construction and assembly of information transfer systems at territorially distributed objects.

6 cl, 8 dwg

Description

The invention relates to methods and systems for transmitting information (STI) through power lines and is intended for use in alarm systems, in systems for automatically collecting data from remote sensors (for example, from meters for electricity, heat, water or gas), as well as in other systems in which a relatively low information transfer rate is acceptable, and the role of the transport medium is played by power lines.

A known method and system for collecting data on a power electric AC network, described in patents RU No. 2226136, G 08 V 25/06, H 04 V 3/54 and RU No. 2244775, H 04 L 27/18, G 08 V 25 / 06. The specified system contains one main node and several subordinate nodes. The known method consists in the fact that using the main node emit a clock signal of a predetermined type, consisting of one or more characters, which is taken simultaneously by all the subordinate nodes. The main node emits the above clock signal periodically at regular intervals, and the slave node with any number N transmits its data during the N-th half-period of the main voltage of the AC electric network, counting from the moment the clock signal ends.

The disadvantage of the technical solutions described above is that the object of their application is only a single-phase AC power electric network, while in practice mainly three-phase power electric networks are used.

Known SPI, using as a transport medium for the transmission of information power three-phase electrical network (US No. 46668934, N 04 M 11/04). All three phases in the specified three-phase power network using reactive coupling devices are combined into a single communication medium, and the receiver is configured to select for demodulating the strongest signal. Due to this, a higher noise immunity of the specified system is provided in comparison with other analogues.

The disadvantage of this SPI is that when connecting subordinate nodes to different phases of a three-phase power network, a phase shift between the moments of symbol synchronization occurs in these nodes due to the presence of a phase difference of 120 ° between the main harmonics of the mains voltage in adjacent phases.

This disadvantage is eliminated in the method of transmitting digital information over the power grid and the system for its implementation, developed by Schlumberger Industries, Inc., (USA) and protected by US patent No. 4968970, H 04 M 11/04. This method is the closest in technical essence to the claimed one and is selected as a prototype of the present invention.

In the prototype method, to compensate for the phase shift, an introduction of phase-locked loops to the subordinate nodes is used. However, such a technical solution places high demands on the computing performance of the hardware of the slave nodes, which significantly complicates and increases the cost of implementing the entire system.

The subject of the present invention is a method for generating the resulting sequence of synchronizing pulses when transmitting information using code messages over an alternating current electric network, in which the moments of the main harmonic of the mains voltage through zero with the derivative of the same sign are determined in the selected phase of the electric network and formed into these moments of the time stamp, while the moments of the transition of the main harmonic of the mains voltage through zero with a derivative of the same sign determine for the remaining phases of the electric network allocated for the transmission of code messages, additional time stamps are formed at these moments, synchronization pulses are generated at the moments of the start of the mentioned marks, symbol information is exchanged between the phases of the AC mains allocated for sending code messages and the resulting sequence of synchronizing pulses is obtained providing a transport function for transmitting information in a single communication environment.

Particular features of the invention are as follows.

The exchange of symbolic information between the phases of the AC mains allocated for transmitting code messages is carried out using a transceiver device configured to receive and / or transmit code messages through the phases of the AC mains.

The exchange of symbolic information between the phases of the AC mains allocated for the transmission of code messages is carried out using identical reactive coupling devices connected between the phases of the AC mains.

Capacitors are used as reactive coupling devices.

Inductive-capacitive reactive coupling devices are used as reactive coupling devices, each of which is performed with two phase terminals connected to conductors of the corresponding phases and a zero terminal connected to the neutral of the alternating current electric network.

Each inductive-capacitive reactive coupling device is made with one parallel and two consecutive LC resonant circuits, while the first terminals of the series LC resonant circuits are taken as the phase terminals of this inductive-capacitive reactive coupling device, the second terminals of the series LC resonant circuits are connected to each other another and connect to the first output of the parallel LC resonant circuit, the second output of which is taken as the zero output of this inductive capacitive reactive about the connecting device.

The objective of the invention is to provide a technology for the formation of the resulting sequence of synchronizing pulses when transmitting information over an electrical AC network. Moreover, the specified resulting sequence of synchronizing pulses should provide relatively inexpensive means for automatically collecting data from a variety of remote sensors connected to the AC power network, and information would be transmitted with sufficiently high noise immunity.

Provided technical result consists in the possibility of significantly simplifying the construction and installation of SPI at geographically distributed facilities.

The essence of the invention is illustrated by drawings.

Figure 1 explains the principle of forming the resulting sequence of synchronizing pulses for a three-phase AC electrical network.

Figure 2 presents the structural diagram of the first embodiment of a system that implements the claimed method.

Figure 3 presents a structural diagram of a second embodiment of a system that implements the claimed method.

Figure 4 presents a structural diagram of a third embodiment of a system that implements the claimed method.

Figure 5.1 - 5.4 presents four options for the implementation of inductive capacitive reactive coupling device.

The following notation is used in the drawings: 1 — communication device; 2 - a comparator; 3 - pulse shaper; 4 - transceiver device; 5 - reactive binder.

The options (figure 2 - figure 4) of the structural diagrams of various systems that implement the method in question differ from each other by the methods of connecting the communication device 1 to an electrical AC network. Any of these options provides for the formation of a supply voltage of the communication device 1 from one or more phases of an alternating current electric network. In figure 1, one of the phases of the electrical AC network is called "Selected (first) phase." It should be noted that the structural diagrams (figure 2 - figure 4) of various systems that implement the method in question are completely symmetrical with respect to any of the phases. That is, any phase of the power three-phase AC network can be arbitrarily called the "First phase", while the "Second phase" will be the phase that is offset from the "First phase" by 120 °, and the remaining phase (shifted from the "First phase" by 240 ° ) will be conditionally considered the "Third phase".

In all variants (Fig. 2 - Fig. 4) of the structural diagrams of the system for transmitting code messages, all three phases of a three-phase alternating current electric network are distinguished. However, in principle, the inventive method does not exclude the possibility of allocating for the transmission of code messages only two of any phases of an electric AC network.

In the first embodiment (figure 2), the communication device 1 contains three comparators 2, the outputs of each of which are connected to the corresponding inputs of the pulse shaper 3. The output of the pulse shaper 3 is connected to the input of the transceiver device 4. Each of the three outputs of the transceiver device 4 is connected to the corresponding phase of the AC electric network and to the inverting input of one of the comparators 2. Non-inverting inputs of all three comparators 2 are connected to ground (to the neutral of the AC network) current).

The difference between the second (figure 3) and third (figure 4) variants of the structural diagram of the system that implements the inventive method, from the first (figure 2) variant of the structural diagram of the system consists in the presence between the conductors of the first and second phases, the second and third phases, the first and the third phase of reactive coupling devices 5. In this case, the second (FIG. 3) and third (FIG. 4) structural scheme variations differ only in the circuitry of reactive coupling devices 5. In the second embodiment, capacitive reactants are used, and in the third, inductive-capacitive reactive binders device wa 5.

The pulse generator 3, which is part of the communication device 1, can be implemented by using the microcontroller microcircuit MSP430F1xx, commercially available from Texas Instruments (USA).

The composition of the communication device 1 includes three comparators 2 with hysteresis, resistant to input noise. Each such comparator 2 can be obtained, for example, by using the LM393 chip, commercially available from National semiconductor (USA). To obtain the required comparator 2, the input “-” of this microcircuit through a 1 MΩ resistor must be connected to the corresponding phase conductor of the AC electric network, and the input “+” of the LM393 microcircuit through a 10 kΩ resistor must be connected to the ground wire (to the neutral of the AC mains) . In addition, the output of the LM393 chip must be connected: through a 1 kΩ resistor to the power bus of the communication device 1 and through a 100 kΩ resistor to the "+" input of the same LM393 chip.

As a comparator 2, a comparator integrated into the microchip of the microcontroller MSP430F1xx, commercially available from Texas Instruments (USA), can also be used. As mentioned above, this chip is used as part of the 3 pulse shaper.

The transceiver 4, which is part of the communication device 1, is commercially available by the applicant company (for example, the catalog "Radio communication systems", "Altonika", 2004/2005). This transceiver device 4 is intended for connection to both power single-phase and power three-phase AC electric networks.

Reactive connecting devices 5, which are included (in the amount of three pieces) in the second (Fig. 3) and third (Fig. 4) variants of the structural diagrams of the system, can be capacitive (in the system embodiment shown in Fig. 3) or inductive-capacitive (in the embodiment of the system shown in figure 4). However, in each of these system options, all three reactive coupling devices 5 must have identical characteristics and completely matching electrical circuits. Reactive coupling devices 5 are designed to ensure the exchange of information between different phases of an alternating current electric network, avoiding overflow of high phase voltage.

In the simplest case, a capacitive reactive coupling device 5 (for the second version of the system shown in FIG. 3) can be a high voltage capacitor (for example, series K73-17).

Possible electrical circuits for constructing an inductive-capacitive reactive coupling device 5 (using two serial and one parallel LC resonant circuits) are shown in Fig. 5.1 - Fig. 5.4.

In each of these options, the terminals of successive LC resonant circuits are connected to the various phases of the AC mains, and one of the terminals of the parallel LC resonant circuit is connected to the neutral of the AC mains, the other terminal of which is connected to the free terminals of the sequential LC resonant circuits ( figure 5.1 - figure 5.4).

Inductive-capacitive reactive coupling device 5 is a filter having frequency selectivity. With the appropriate selection of capacitance and inductance values, the resistance of the reactive coupling device 5 in the frequency range at which the code messages are exchanged is negligible, and all three phases of the AC mains turn into a single transport highway for transmitting code messages from remote sensors. The high phase voltage of an alternating current electric network and out-of-band interference cannot propagate from one phase of an alternating current electric network to another phase of this network.

High-voltage capacitors (for example, K73-17 series) can be used as capacitive elements in inductive-capacitive reactive coupling devices 5, and, for example, power inductors manufactured in series by ABC (Taiwan) can be used as inductive elements.

Thus, in all variants (Fig. 2 - Fig. 4) of constructing a system that implements the inventive method, commercially available and available on the commercial market products of electronic equipment. Therefore, the possibility of practical implementation of the proposed method is not in doubt. Moreover, the claimed method can be implemented using various circuit designs of the system, specifically indicated in figure 2 - figure 4.

Variants of structural diagrams (Fig. 2 - Fig. 4) of building a system that implements the claimed method of generating the resulting sequence of synchronizing pulses when transmitting information using code messages on an alternating current electric network, work as follows.

For the considered three-phase power AC mains, the sinusoids of the alternating current in the adjacent phases are offset from each other by 120 ° (Fig. 1). The time moments of the intersection of each of the sinusoids of alternating current of zero level at the same sign of the derivative define the initial moments of time for the pulses forming the resulting sequence of synchronizing pulses.

In Fig. 1, such time instants (with a positive derivative selected for each phase of an alternating current sinusoid) are marked with dots. At each of the indicated time points, a time stamp (or an additional time stamp) is formed, each of which causes the formation of a subsequent synchronizing pulse for a given phase. When combining the synchronizing pulses generated in various phases of the AC electric network, the resulting sequence of synchronizing pulses is obtained, as shown in figure 1.

For any (figure 2 - figure 4) version of the system, each of the comparators 2 included in the communication device 1 captures the moment of coincidence of the voltage supplied to its inverting input with the voltage at the non-inverting input. With this match, the sign of the derivative of the variable signal is taken into account. In particular, if the non-inverting input of the comparator 2 is connected to the neutral of the electric network, and the inverting input is connected to one of the phases of the same electric network, then the comparator 2 highlights those times when the main harmonic of the mains voltage in this phase passes through zero when the signal of the main harmonics of the mains voltage. At these time points highlighted by (Fig. 1), the corresponding comparator 2 generates time stamp signals, as shown in Fig. 1. In this case, in Fig. 1, some "first" phase is conditionally called "selected". Due to the symmetry of constructing structural diagrams of systems that implement the inventive method (figure 2 - figure 4), such a first selected phase can be any of the phases of a three-phase AC electrical network.

The signals of the time stamps (from the output of the comparator 2 of the selected phase) and additional time stamps (from the outputs of the remaining comparators 2 included in the switching device 1) fall into the pulse shaper 3. When each signal of the time stamp or additional time stamp arrives, the pulse shaper 3 generates at its output another synchronizing pulse.

Thus, at the output of the pulse shaper 3, the resulting sequence of synchronizing pulses shown in Fig. 1 is formed. In this resulting sequence of synchronizing pulses, the beginning of each synchronizing pulse corresponds to the transition through zero of the main harmonic of the mains voltage in each phase of the AC mains with an increase in the main harmonic of the mains voltage. Thus, the resulting resulting sequence of clock pulses is a combination of phase symbolic clock pulses with a frequency equal to three times the network frequency.

The resulting resulting sequence of synchronizing pulses is fed to the input of the transceiver 4.

Further, the work of system options that implement the inventive method occurs with certain differences caused by various circuit implementation of these options (figure 2 - figure 4).

In the first embodiment of the system (Fig. 2), the three outputs of the transceiver device are connected to the corresponding phases of the power three-phase electric alternating current network. Due to this, the code messages transmitted or received by the transceiver device 4 at various phases of the AC electric network are “attached” to the resulting sequence of synchronizing pulses. In other words, all phases of the AC electric network through the transceiver 4 realize the transport function in a single communication environment. Accordingly, there is no need for phase locked loop. This greatly simplifies the technical implementation of the system of automatic data collection from remote sensors, in comparison with the known technical solutions.

The second (Fig. 3) and third (Fig. 4) variants of a system that implements the method in question are characterized in that the exchange of information between the first and second, second and third, first and third phases of an alternating current electric network, which implements a transport function in a single communication environment, carried out using reactive coupling devices 5. In addition, as in the first embodiment of the system that implements the method in question (figure 2), the transport function in a single communication environment is implemented through the receiver giving device 4. These two different ways of implementing transport independent functions in a single circuit environment improve reliability of the system (by introducing redundancy circuit).

The principle of operation of reactive binding devices 5 is as follows. Between any two phases of the AC mains, a high linear voltage is applied, exceeding the voltage of each of the phases separately. For this reason, direct galvanic connection of conductors of different phases of the AC mains is not possible, and reactive coupling devices 5 can be used to ensure the exchange of code messages between different phases of the AC mains. They must provide high resistance at the operating frequency of the AC mains and small resistance - in the frequency range at which code messages are exchanged. These requirements can be met by using reactive coupling components - high voltage capacitors and inductors.

In the simplest case (the second option, shown in FIG. 3), a capacitive reactive coupling device 5 is used, which is a capacitor connected between the conductors of the corresponding phases of the AC electric network. By selecting the capacitance of the indicated capacitor, it is possible to achieve that at the frequencies of the exchange of code messages the resistance of the reactive coupling device 5 is small, and the code messages could propagate from one phase of the AC electric network to another phase of this network.

It is possible to completely eliminate the possibility of out-of-band interference from one phase of an alternating current electric network to another phase of this network (the third option shown in Fig. 4) using inductive-capacitive reactive coupling devices 5. Each such inductive-capacitive reactive coupling device 5 should be built of several reactive elements (Fig.5.1 - Fig.5.4). In this case, a filter is formed with frequency selectivity, and with appropriate selection of capacitance and inductance values, the resistance of such an inductive-capacitive reactive coupling device 5 in the range of code messaging frequencies is negligible. The high phase voltage of the AC mains, as well as out-of-band noise and interference, cannot propagate from one phase of the AC mains to other phases of this AC mains.

In the event that only two phases of an alternating current electric network are allocated for transmitting code messages, then a single reactive coupling device 5 must be installed between the separated phases. However, a common case is the allocation of all three phases of a three-phase power alternating current electric network for transmitting code messages.

After combining the phases of a three-phase AC network selected for transmitting code messages into a single communication medium, it becomes possible to generate a resulting sequence of synchronizing pulses for transmitting code messages from remote sensors through the selected phases of a three-phase AC power network without using a phase-locked loop.

This allows us to solve the problem of the invention - to create a technology for the formation of the resulting sequence of synchronizing pulses when transmitting information using code messages on an alternating current electric network. Moreover, the specified resulting sequence of synchronizing pulses provides, when using relatively inexpensive means, automatic data collection from a variety of remote sensors connected to a three-phase AC power network, and information is transmitted using code messages with a fairly high noise immunity.

Provided technical result consists in the possibility of significantly simplifying the construction and installation of SPI, implementing the claimed method, on geographically distributed objects.

Claims (6)

1. The method of generating the resulting sequence of synchronizing pulses when transmitting information using code messages on an alternating current electric network, in which in the selected phase of the electric network the moments of the transition of the main harmonic of the network voltage through zero with the derivative of the same sign are determined and labels are formed at these moments time, characterized in that the moments of the transition of the main harmonic of the mains voltage through zero with the derivative of the same sign determine for the remaining phases the electric of the network allocated for the transmission of code messages, additional time stamps are formed at these moments, synchronization pulses are generated at the start points of the mentioned marks, symbol information is exchanged between the phases of the AC mains allocated for the transmission of code messages, and the resulting sequence of synchronizing pulses providing transport function for transmitting information in a single communication environment. 2. The method according to claim 1, characterized in that the exchange of symbolic information between the phases of the AC mains allocated for transmitting code messages is carried out using a transceiver device configured to receive and / or transmit code messages through the phases of the AC mains . 3. The method according to claim 1, characterized in that the exchange of symbolic information between the phases of the AC mains allocated for the transmission of code messages is carried out using identical reactive coupling devices connected between the phases of the AC mains. 4. The method according to claim 3, characterized in that capacitors are used as reactive coupling devices. 5. The method according to claim 3, characterized in that inductive reactive coupling devices use inductive-capacitive reactive coupling devices, each of which is performed with two phase terminals connected to the conductors of the corresponding phases, and a zero terminal connected to the neutral of the alternating electrical network current. 6. The method according to claim 5, characterized in that each inductive-capacitive reactive coupling device is made with one parallel and two consecutive LC resonant circuits, while the first conclusions of consecutive LC resonant circuits are taken as the phase outputs of this inductive capacitive reactive binder devices, the second terminals of successive LC resonant circuits are connected to each other and connected to the first terminal of a parallel LC resonant circuit, the second terminal of which is taken as the zero output given inductive capacitive reactive coupling device.

Images