JP2017143606A - Device having communication facility and internal value matching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of controlling influence to convergence of an internal value even when communication is failed.SOLUTION: A device A comprises: an internal value generation unit 1 that generates an internal value X; and a communication unit 2 that performs a communication with at least one device. In the device, the internal value generation unit 1 uses the generated internal value Xand an arithmetic result based on an internal value Xreceived by the communication unit 2 from at least one of other devices A, and generates the internal value X. The communication unit 2 transmits the internal value Xgenerated by the internal value generation unit 1 to at least one of other devices A, and does not perform retransmission of the transmitted internal value Xeven when a communication failure occurs at the transmission. Thus, the device can prevent a failure of scattering of convergence of the internal value Xthat is generated by retransmitting the internal value Xat the communication failure, and receiving an old internal value Xby the device A as a communications partner. Therefore, even when the communication is failure, the device can suppress the influence to convergence of the internal value X.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a device having a communication function and capable of matching the internal value by transmitting / receiving the internal value to / from another device, and a method for matching the internal value.

  A method has been developed in which internal values of a plurality of devices are not matched by a management device that manages these devices as a whole, but each device sends and receives internal values through communication. In this method, each device transmits / receives an internal value to / from at least one other device, and generates an internal value using a calculation result based on the generated internal value and the received internal value. By performing this process in each device, the internal value of each device converges to the same value. As an example using this method, Patent Document 1 describes that the internal phase of the inverter device is synchronized, and Patent Document 2 discloses that the amount of suppression of the output active power is reduced by matching the compensation values of each inverter device. It is described that adjustment is performed, and Patent Document 3 describes that each measurement device calculates an overall average value by matching internal average values based on measurement values.

Japanese Patent Application Laid-Open No. 2015-027155 JP 2015-084612 A JP2015-166901A

Reza Olfati-Saber, J. Alex Fax, and Richard M. Murray, "Consensus and Cooperation in Networked Multi-Agent Systems", Proceedings of the IEEE, Vol. 95, No. 1, (2007) Mehran Mesbahi and Magnus Egerstedt, "Graph Theoretic Methods in Multiagent Networks", Princeton (2010)

  However, in this method, it has been confirmed that a failure occurs in the convergence of the internal value by retransmitting the internal value when communication fails. FIG. 4 is a diagram for explaining the failure. Each device transmits at its own timing. When the operation timing is not synchronized with other devices, each device performs an operation every time it receives an internal value from one other device.

4 (a) is a transmission timing of the internal value X ₁ from the apparatus A1 to the device A2, by the transmission timing of the internal value X ₂ from the apparatus A2 to the device A1 matches, internal device A1 sends the value X ₁ of the device A2 indicates a state that could not be received correctly. If the transmission timing is not controlled, the transmission timing may rarely coincide. In this case, the device A2 (or router) transmits a signal requesting retransmission to the device A1. FIG. 4B shows that the internal value X ₃ is transmitted from the device A3 to the device A2 and received. In this case, device A2 performs calculation based on the internal value X ₃ received the internal value X ₂ of the apparatus, and updates the internal value X _2.

FIG. 4 (c), in response to a request of retransmission, devices A1 it is indicated that the received resend the internal value X ₁ to device A2. In this case, device A2 performs calculation based on the internal value X ₂ of the internal value X ₁ and its own device with the received updates the internal value X _2. The internal value X ₁ was originally received at the timing of FIG. 4A and should be used for the calculation of the internal value X ₂ . However, the internal value X ₂ has already been updated by the calculation based on the previously received internal value X ₃ . In FIG. 4, transmission / reception with three devices is described for the sake of simplification, but actually, internal values are transmitted / received to / from more devices. That is, the internal value X ₂ is updated many times toward convergence. Similarly, it has been updated several times toward the internal value X ₁ of the apparatus A1 in convergence. Updating the internal value X ₂ wherein in operation based on the internal value X ₁ is old information, the value of the internal value X ₂ which has been toward convergence, will be updated to a value largely deviated. In this case, when the internal value X ₂ is transmitted to another device, the internal value of the device that has received the internal value X ₂ is also affected, and the influence spreads throughout the entire system. As a result, the convergence of the internal value is disturbed, and the time for convergence increases.

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide an apparatus capable of suppressing the influence on the convergence of internal values even when communication fails. It is said.

  In order to solve the above problems, the present invention takes the following technical means.

  An apparatus provided by the first aspect of the present invention includes an internal value generation unit that generates an internal value, and a communication unit that communicates with at least one other device, and the internal value generation unit includes the generation unit. The internal value is generated using a calculation result based on the internal value and the internal value received by the communication means from at least one of the other devices, and the communication means is generated by the internal value generation means. An internal value is transmitted to at least one of the other devices, and when a communication failure occurs during transmission, the transmitted internal value is not retransmitted.

  In a preferred embodiment of the present invention, when the communication unit receives a retransmission request due to communication failure, the communication unit fails to receive the internal value generated by the internal value generation unit when the retransmission request is received. Sent to the device.

  In a preferred embodiment of the present invention, when the communication unit fails to receive from the other device, the communication unit does not transmit a retransmission request to the other device.

  In a preferred embodiment of the present invention, the internal value generation means integrates a calculation means for performing a calculation based on the generated internal value and the received internal value, and a calculation result output by the calculation means. And integrating means for calculating the internal value.

  In a preferred embodiment of the present invention, the calculation means calculates the calculation result by subtracting the generated internal value from the received internal value and adding all the subtraction results.

  The method provided by the second aspect of the present invention is a method in which a plurality of devices including an internal value generating unit that generates an internal value and a communication unit that communicates with at least one other device match the internal value. A first step in which the internal value generation means generates an internal value, a second step in which the internal value generated in the first step is transmitted to at least one other device, and at least one other The third step of receiving the internal value transmitted by the device is performed by each device, and the first step includes the generated internal value and the internal value received in the third step. An internal value is generated using a calculation result based on this, and when the transmission fails in the second step, the transmitted internal value is not retransmitted.

  According to the present invention, even if a communication failure occurs at the time of transmission, since the transmitted internal value is not retransmitted, the convergence of the internal value, which occurs when the communication partner apparatus receives the old internal value, is disturbed. Can avoid the obstacle. Therefore, even when communication fails, the influence on the convergence of the internal value can be suppressed.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a figure for demonstrating the apparatus which concerns on 1st Embodiment. It is a flowchart for demonstrating the transmission / reception process which the communication part which concerns on 1st Embodiment performs. It is a flowchart for demonstrating the modification of the transmission / reception process which the communication part which concerns on 1st Embodiment performs. It is a figure for demonstrating the failure which generate | occur | produces when retransmission of an internal value is performed when communication fails.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a diagram for explaining an apparatus according to the first embodiment. FIG. 1A is a block diagram showing an internal configuration of the device A according to the first embodiment. FIG. 1B shows a state in which a plurality of devices A are communicating with neighboring devices A.

As illustrated in FIG. 1A, the device A includes an internal value generation unit 1 that generates an internal value X _i and a communication unit 2 that performs communication with another device A. The device A performs control based on the internal value X _i generated by the internal value generation unit 1 or performs calculation using the internal value X _i . In practice, the device A includes control means for performing control by inputting the internal value X _i , calculation means for performing calculation, display means for displaying the internal value X _i , etc., depending on the application. However, in this embodiment, description and explanation of these means are omitted.

The communication unit 2 communicates with another device A. The communication unit 2 receives the internal value X _i generated by the internal value generation unit 1 and transmits it to the communication unit 2 of another device A. Further, the communication unit 2 outputs the internal value X _j received from the communication unit 2 of the other device A to the internal value generation unit 1. Note that the communication method is not limited, and may be wired communication or wireless communication.

  As shown in FIG. 1B, the device A communicates with another device A, and the entire device A that performs communication forms a network. FIG. 1B shows a state in which five devices A (A1 to A5) constitute a network. Note that an actual network is configured with a larger number of devices A, but extremely few cases are shown for simplicity of explanation.

  A solid line arrow shown in FIG. 1B indicates that mutual communication is performed. The device A1 performs mutual communication only with the device A2, and the device A2 performs mutual communication only with the devices A1 and A3. In addition, the device A3 performs mutual communication only with the devices A2 and A4, the device A4 performs mutual communication only with the devices A3 and A5, and the device A5 performs mutual communication only with the device A4. As described above, the communication unit 2 of the device A is connected to the communication unit 2 of at least one device A (for example, a device located in the vicinity or one in which communication is established) among the devices A configuring the network. As long as the communication path exists for any two devices A that are communicating and that constitute the network (hereinafter, this state is referred to as a “connected state”), the network It is not necessary to communicate with the communication units 2 of all the devices A that are configured.

For example, if the apparatus A of the apparatus A2, the communication unit 2 transmits the internal value X ₂ of the internal value generating unit 1 is generated in the communication unit 2 of the device A1 and A3, the internal value X from the communication unit 2 of the device A1 ₁ is received, and the internal value X ₃ is received from the communication unit 2 of the device A3.

When communication fails and data cannot be received correctly, a normal communication unit (or router) transmits a retransmission command for retransmitting data that could not be received to the communication unit that is the transmission source. When receiving the retransmission instruction, the transmission source communication means retransmits the data. Thereby, the communication means of the reception source can receive data that could not be received. However, when the communication unit 2 according to the present embodiment receives a retransmission instruction, the communication unit 2 does not retransmit the internal value X _i at the time of communication failure, but acquires the internal value X _i from the internal value generation unit 1 again. The latest internal value X _i is transmitted.

  FIG. 2 is a flowchart for explaining the transmission / reception processing performed by the communication unit 2. The transmission / reception process is started when the device A is activated.

First, it is determined whether or not a predetermined timing has come (S1). The communication unit 2 measures time based on an internal clock (not shown), and determines whether or not it is a predetermined timing based on whether or not the measured time has reached a predetermined time. In the present embodiment, the predetermined timing is, for example, every second, but is not limited thereto. When the predetermined timing is reached (S1: YES), the internal value X _i is acquired from the internal value generation unit 1 (S2), transmitted to another device A (S3), and the process returns to step S1.

In step S1, if the predetermined timing is not reached (S1: NO), it is determined whether or not the internal value X _j has been received (S4). When the internal value X _j is received (S4: YES), the received internal value X _j is output to the internal value generation unit 1 (S5), and the process returns to step S1. The internal value generator 1 performs a calculation based on the input internal value X _j and the internal value X _{i at} this time, and generates a new internal value X _i .

In step S4, if the internal value _Xj has not been received (S4: NO), it is determined whether or not a retransmission request has been received (S6). When the re-transmission request is received (S6: YES), the internal value X _i is acquired from the internal value generation unit 1 (S7) and transmitted to the other apparatus A that has transmitted the re-transmission request (S8), step Return to S1. That is, the latest internal value X _i is transmitted instead of the internal value X _i at the time of communication failure.

  In step S6, when the retransmission request has not been received (S6: NO), it is determined whether or not the reception has failed (S9). For example, if the error detection code of the received data is not appropriate, it is determined that the reception has failed. If the reception has failed (S9: YES), a retransmission request is transmitted to the transmission source device A (S10), and the process returns to step S1. If reception has not failed (S9: NO), the process returns to step S1, and the determinations of steps S1, S4, S6, and S9 are repeated. Note that the router may transmit the retransmission request instead of the communication unit 2 when reception fails. In this case, steps S9 and S10 are not performed. In addition, the transmission / reception process which the communication part 2 performs is not limited to what was mentioned above.

Returning to FIG. 1, the internal value generation unit 1 is realized by a microcomputer, for example, and generates the generated internal value X _i and the internal value X _j of another device A input from the communication unit 2. To generate an internal value X _i . Even if the internal value X _i is different from the internal value X _j , the internal value X _i and the internal value X _j converge to a common internal phase by repeating the arithmetic processing in the internal value generation unit 1. As shown in FIG. 1A, the internal value generation unit 1 includes a calculation unit 11, a multiplier 12, and an integrator 13.

The calculation unit 11 performs a calculation based on the following equation (1). That is, the calculation unit 11 subtracts the internal value X _i generated by the internal value generation unit 1 from each internal value X _j input from the communication unit 2 and multiplies the calculation result u _i by adding all the subtraction results. To the device 12.

For example, when the device A is the device A2 (see FIG. 1B) and the internal value X _j is received simultaneously from the device A1 and the device A3, the calculation unit 11 performs the calculation of the following equation (2), The result u ₂ is output.

In the present embodiment, the calculation timing in the calculation unit 11 of each device A is not synchronized, and the calculation unit 11 performs sequential calculation every time the internal value X _j is received from any of the devices A. For example, the operation unit 11 of the device A2, upon receiving the internal value X ₁ from the device A1, when calculating the u ₂ = X ₁ -X _2, receives the internal value X ₃ from the device A3, u ₂ = X ₃ -X ₂ is calculated.

The multiplier 12 multiplies the calculation result u _i input from the calculation unit 11 by a predetermined coefficient ε and outputs the result to the integrator 13. The coefficient ε is a value that satisfies 0 <ε <1 / d _max and is set in advance. d _max is the maximum number of internal values X _j that may be simultaneously input to the communication unit 2. Note that the coefficient ε is multiplied by the calculation result u _i in order to prevent the input to the integrator 13 from becoming too large (small) and the fluctuation of the internal value X _{i from} becoming too large.

The integrator 13 integrates the value input from the multiplier 12 to generate and output the internal value X _i . Integrator 13 generates an internal value X _i by adding the value input from the multiplier 12 to the internal value X _i previously generated. The internal value X _i is output to the communication unit 2 and the calculation unit 11.

In this embodiment, the internal value generating unit 1 uses the internal value X _i of the generated, is input from the communication unit 2, an internal value X _j of the other device A, to generate an internal value X _i. When the internal value X _i is larger than the internal value X _j , the calculation result u _i output from the calculation unit 11 is a negative value. Then, the negative value is added to the integrator 13, and the internal value X _i becomes small. On the other hand, when the internal value X _i is smaller than the internal value X _j , the calculation result u _i output from the calculation unit 11 is a positive value. Then, a positive value is added to the integrator 13 so that the internal value X _i increases. That is, the internal value X _i approaches the internal value X _j . By performing this process in each device A, the internal value X _i of each device A converges to the same value. It has been proved mathematically that the internal value X _i converges to the same value Xα (see Non-Patent Documents 1 and 2). Further, when the calculation timings in the calculation unit 11 of each device A are synchronized, the convergence value Xα is an addition of the initial value of the internal value X _i of each device A as shown in the following equation (3). It has also been proved to be an average value. n is the number of devices A constituting the network, and the following equation (3) is an arithmetic average value obtained by adding all initial values of internal values X _{1 to} X _n of the devices A ₁ to An and dividing by n. Is calculated. However, since the timing is not synchronized in the present embodiment, the convergence value Xα does not necessarily converge to the arithmetic mean value. However, since they converge to the same value, it does not matter that the convergence value Xα is not an arithmetic mean value.

  Next, the operation of the device A will be described.

According to this embodiment, when the communication unit 2 receives a retransmission instruction due to communication failure, the communication unit 2 does not retransmit the internal value X _i at the time of communication failure, but retransmits the internal value X _i from the internal value generation unit 1. Acquire and transmit the latest internal value X _i . Therefore, the transmission destination apparatus A can receive the latest internal value X _i after being updated many times toward convergence as the internal value X _j . Accordingly, an internal value X _i for communication failure than if received as an internal value X _j is retransmitted, it is possible to suppress the influence on the convergence of the internal value.

Further, according to the present embodiment, the internal value generation unit 1 can update the internal value X _i to be close to the internal value X _j by the calculation in the calculation unit 11 and the integration in the integrator 13.

  In the first embodiment, the case where the calculation unit 11 performs the calculation based on the equation (1) has been described. However, the present invention is not limited to this.

For example, the calculation formula set in the calculation unit 11 may be the following formula (4). In this case, the convergence value Xα is different from the case where the above equation (1) is used, but the internal value X _i converges to the same value. d _i is the number of internal values X _j input to the communication unit 2.

Moreover, it is good also considering the arithmetic expression set to the calculating part 11 as following (5), (6), (7) Formula. In these cases, the convergence value Xα is different from the case of using the above equation (1), but the internal value X _i converges to the same value.

In the first embodiment, the case where the calculation timings in the calculation units 11 of the devices A are not synchronized has been described, but the present invention is not limited to this. The calculation timings in the calculation unit 11 of each device A may be synchronized. In this case, the calculation unit 11 performs the calculation of the above formula (1) at a predetermined timing based on each internal value X _j received by the communication unit 2. If so shifting the timing of the communication unit 2 of the device A outputs the internal value X _i gradually communications failure is unlikely to occur. Further, even when communication failure occurs, if the device A that has failed in communication retransmits before the calculation timing in the calculation unit 11 comes, the internal value X _i is not updated, Since the calculation timing at the transmission destination is in time, the convergence of the internal value is not disturbed. Even when the device A that has failed in communication performs retransmission after the timing of computation in the computation unit 11 has arrived, the internal value X _i after being updated is transmitted, so the influence on the convergence of the internal value Can be suppressed.

Although the case where the communication unit 2 transmits the latest internal value X _i has been described in the first embodiment, the present invention is not limited to this. For example, when transmission fails, nothing may be transmitted until the next transmission timing.

  FIG. 3 is a flowchart for explaining a modification of the transmission / reception process performed by the communication unit 2. The transmission / reception process is started when the device A is activated.

First, it is determined whether or not a predetermined timing has come (S1). When the predetermined timing is reached (S1: YES), the internal value X _i is acquired from the internal value generation unit 1 (S2), transmitted to another device A (S3), and the process returns to step S1. In step S1, if the predetermined timing is not reached (S1: NO), it is determined whether or not the internal value X _j has been received (S4). When the internal value X _j is received (S4: YES), the received internal value X _j is output to the internal value generation unit 1 (S5), and the process returns to step S1. If the internal value X _j is not received in step S4 (S4: NO), the process returns to step S1 and the determinations of steps S1 and S4 are repeated. In other words, the transmission / reception process of this modification does not transmit a retransmission request even if reception fails, and does not perform the retransmission process even if a retransmission request is received. In addition, the transmission / reception process which the communication part 2 performs is not limited to what was mentioned above.

In the present modification, the corresponding process is not performed even when communication fails, so that the internal value X _i at the time of communication failure is not retransmitted. Therefore, the convergence of the internal value is not greatly disturbed. If the communication fails, the internal value X _i is not updated by the communication, but the latest internal value X _j is received at the next communication timing and the internal value X _i is updated. The convergence of _i is not greatly disturbed. That is, the influence on the convergence of the internal value X _i can be suppressed more than when the internal value X _i at the time of communication failure is retransmitted.

  The present invention can be applied to any device that has a communication function and that matches internal values by transmitting and receiving internal values to and from other devices configuring the network. For example, when synchronizing the internal phase of each inverter device that constitutes the power system, or when matching various timings or shifting so that they do not match, the internal compensation values of each inverter device that constitutes the power system are matched. Thus, when adjusting the suppression amount of the output active power and the output reactive power, the present invention can be applied to the case where each measurement device matches the internal average value, the maximum value, and the minimum value based on the measurement value.

  The apparatus provided with the communication function according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the apparatus having the communication function according to the present invention can be varied in design in various ways.

A, A1 to A5 Device 1 Internal value generation unit 11 Calculation unit 12 Multiplier 13 Integrator 2 Communication unit

Claims (6)

An internal value generating means for generating an internal value;
Communication means for communicating with at least one other device;
With
The internal value generation means generates an internal value using a calculation result based on the generated internal value and the internal value received by the communication means from at least one of the other devices,
The communication means includes
Transmitting the internal value generated by the internal value generating means to at least one of the other devices;
If a communication failure occurs during transmission, the transmitted internal value is not retransmitted.
A device characterized by that. When the communication means receives a retransmission request due to communication failure,
Transmitting the internal value generated by the internal value generation means when the retransmission request is received, to a device that has failed to receive,
The apparatus of claim 1. The communication means does not send a retransmission request to the other device when reception from the other device fails,
The apparatus of claim 1. The internal value generation means includes
A calculation means for performing a calculation based on the generated internal value and the received internal value;
Integration means for calculating an internal value by integrating a calculation result output by the calculation means;
With
The apparatus according to claim 1. The calculation means calculates the calculation result by subtracting the generated internal value from the received internal value and adding all the subtraction results,
The apparatus according to claim 4. A plurality of devices comprising an internal value generating means for generating an internal value and a communication means for communicating with at least one other device, the internal values being matched,
A first step in which an internal value generating means generates an internal value;
A second step of transmitting the internal value generated in the first step to at least one other device;
A third step of receiving an internal value transmitted by at least one other device;
Is performed on each device,
The first step generates an internal value using a calculation result based on the generated internal value and the internal value received in the third step,
When transmission fails in the second step, the transmitted internal value is not retransmitted.
A method characterized by that.

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