JP2023141263A - Communication system - Google Patents

Abstract

To provide a communication system capable of appropriately converging internal values regardless of the performance and communication environment of each device.SOLUTION: A communication system B includes a plurality of devices A each having a communication function. Each of the plurality of devices A includes an internal value generation unit 31 that generates an internal value Xi, and a communication unit 34 that communicates with at least one other device A. The communication unit 34 transmits the internal value Xi generated by the internal value generation unit 31 to at least one of the other devices A. The internal value generation unit 31 updates the generated internal value Xi using a calculation result based on the generated internal value Xi and an internal value Xj received by the communication unit 34 from the at least one of the other devices A. The timing at which the communication unit 34 performs transmission is different from timings at which the communication units 34 of the other devices A perform transmission.SELECTED DRAWING: Figure 1

Description

The present invention relates to a communication system including a plurality of devices, each of which has a communication function, and which matches internal values by transmitting and receiving internal values to and from other devices.

A method has been developed in which the internal values of a plurality of devices are matched by each device transmitting and receiving internal values through communication, instead of being matched by a management device that manages all of these devices. In this method, each device transmits and receives an internal value to at least one other device, and updates the 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 values of each device converge to the same value. As an example of using this method, Patent Document 1 describes synchronizing the internal phases of inverter devices, and Patent Document 2 describes that by matching the compensation values of each inverter device, the amount of suppression of output active power is reduced. Patent Document 3 describes that each measuring device makes the internal average values based on the measured values coincide with each other to calculate the overall average value.

JP2015-027155A JP2015-084612A Japanese Patent Application Publication No. 2015-166901

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)

In the inventions described in Patent Documents 1 to 3, if the acquisition timings of the internal values do not match in the calculation based on the generated internal value and the received internal value, the calculation may not converge properly or the internal value may be incorrect. Problems such as not converging to the desired value may occur. In order to prevent these problems, it is necessary to transmit and receive internal values between each device, perform calculations based on the internal values, and update the internal values using the calculation results at the same timing. Particularly, in a system that requires high synchronization accuracy, such as the invention described in Patent Document 1, the performance of each device and the communication environment are major constraints, making it a challenge to realize the system.

The present invention was conceived under the circumstances described above, and its purpose is to provide a communication system that can appropriately converge internal values regardless of the performance of each device or the communication environment. There is.

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

A communication system provided by a first aspect of the present invention is a communication system including a plurality of devices each having a communication function, and each of the plurality of devices includes an internal value generating means for generating an internal value. and communication means for communicating with at least one other device, the communication means transmits the internal value generated by the internal value generation means to at least one of the other devices, and the communication means transmits the internal value generated by the internal value generation means to at least one of the other devices, The value generation means updates the generated 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, and updates the generated internal value. It is characterized in that the timing at which the means transmits data is different from that of the communication means of the other devices.

In a preferred embodiment of the present invention, when the communication means receives an internal value from any of the other devices, the internal value generation means combines the received internal value with the internal value generated at this time. The difference is calculated and used as the subtraction result.

In a preferred embodiment of the present invention, the internal value generating means calculates the value between the previous update timing and the current update timing at an update timing different from the timing at which the communication means of each device transmits. The generated internal value is updated using the subtraction result.

In a preferred embodiment of the present invention, when the number of the plurality of devices is n and the cycle of the update timing is Δt, the timing at which each communication means of the plurality of devices transmits is (Δt/ (n+1)).

In a preferred embodiment of the present invention, the internal value generated by the internal value generating means is constantly changing.

According to the present invention, the internal value generation means updates the internal value using a calculation result based on the generated internal value and the internal value of another device received by the communication means. The internal value generation means of each device similarly updates, so that the internal values of all devices converge to the same value. The communication means of a certain device transmits internal values at different timings from the communication means of other devices, so the timing of transmitting internal values to other devices and the timing of receiving internal values from other devices are different. It can be shifted. As a result, in the communication system according to the present invention, compared to a case where the communication means of each device transmits internal values at the same timing as the communication means of other devices, hard to receive.

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

1 is a diagram for explaining a communication system according to a first embodiment, in which (a) is a diagram showing the communication state of a plurality of devices that constitute the communication system, and (b) is a block diagram showing the internal configuration of each device; FIG. It is a diagram. FIG. 3 is a diagram for explaining an example of communication between devices. 3 is an example of a flowchart for explaining an internal value update process performed by a control circuit of the device. It is a diagram for explaining a communication system according to a second embodiment, and is a block diagram showing the internal configuration of each device that constitutes the communication system.

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

FIG. 1 is a diagram for explaining a communication system B according to the first embodiment. FIG. 1A is a diagram showing the communication status of a plurality of devices A that constitute a communication system B. FIG. FIG. 1(b) is a block diagram showing the internal configuration of each device A. In this embodiment, each device A is a distributed power source, and the communication system B synchronizes the internal phases of the inverter devices of the devices A (distributed power sources) connected in parallel with each other.

As shown in FIG. 1(a), each device A communicates with other devices A, and the entire communicating devices A constitute a network. FIG. 1(a) shows a state in which five devices A (A1 to A5) constitute a network. Note that although the actual network is composed of a larger number of devices A, an extremely small number of devices A is shown to simplify the explanation.

The solid arrows shown in FIG. 1(a) indicate that mutual communication is being performed. In this embodiment, each of the devices A1 to A5 is in mutual communication with all other devices A. Note that in the communication system B, it is not necessary for each of the devices A1 to A5 to mutually communicate with all other devices A. Each device A is communicating with at least one device A (for example, one located nearby or with which communication has been established) among the devices A making up the network, and forming the network. Any state in which a communication path exists between any two devices A (hereinafter, this state will be referred to as a "connected state") may be sufficient.

As shown in FIG. 1(b), in this embodiment, the device A is a distributed power source and includes a DC power source 1, an inverter circuit 2, and a control circuit 3. Device A converts DC power output from a DC power supply 1 into AC power using an inverter circuit 2 and outputs the converted AC power. A combination of the inverter circuit 2 and the control circuit 3 is an inverter device, which is called a power conditioner. Note that the configuration of device A is not limited.

The DC power supply 1 outputs DC power and includes, for example, a solar cell. Solar cells generate DC power by converting sunlight energy into electrical energy. The DC power supply 1 outputs the generated DC power to the inverter circuit 2. Note that the DC power source 1 is not limited to one that generates DC power using a solar cell. The inverter circuit 2 converts DC power input from the DC power supply 1 into AC power and outputs the AC power. The inverter circuit 2 converts DC power into AC power by switching each switching element on and off based on a PWM signal input from the control circuit 3. Note that the configuration of the inverter circuit 2 is not limited.

The control circuit 3 controls the inverter circuit 2, and is realized by, for example, a microcomputer. The control circuit 3 generates a PWM signal based on the input voltage, output voltage, output current, etc. of the inverter circuit 2 detected by each sensor provided in the device A, and outputs the PWM signal to the inverter circuit 2. The control circuit 3 includes an internal value generation section 31, a command signal generation section 32, a PWM signal generation section 33, and a communication section 34.

The internal value generation unit 31 generates an internal phase used to generate a command signal as an internal value _Xi . In this specification, the internal value generated by the own device (i-th device A) is expressed as X _i . When the number of devices A is n (n=5 in the example of FIG. 1(a)), i is a natural number from 1 to n. Details of the internal value generation section 31 will be described later.

The command signal generation section 32 generates a command signal for controlling the output voltage. The command signal generation unit 32 performs so-called three-phase/two-phase conversion processing (αβ conversion processing) and rotational coordinate conversion processing (dq conversion processing) on the three-phase voltage signal detected as the output voltage of the inverter circuit 2. Convert to axis component and q-axis component signals. Three-phase/two-phase conversion processing is a process that converts a three-phase AC signal into an equivalent two-phase AC signal, and converts a three-phase AC signal into a stationary orthogonal coordinate system (hereinafter referred to as a "stationary coordinate system"). By decomposing the signal into orthogonal α-axis and β-axis components and adding the components of each axis, an AC signal of the α-axis component and an AC signal of the β-axis component are converted. In addition, rotational coordinate conversion processing is processing that converts two-phase signals (α-axis component and β-axis component) of a stationary coordinate system into two-phase signals (d-axis component and q-axis component) of a rotating coordinate system. . The rotating coordinate system is an orthogonal coordinate system that has orthogonal d and q axes and rotates at a predetermined angular frequency ω ₀ . The rotational coordinate conversion process is performed based on the internal value X _i (internal phase) input from the internal value generation unit 31.

The command signal generation unit 32 extracts only the DC component from the d-axis component and the q-axis component of the voltage signal, performs control processing on each separately, and performs stationary coordinate transformation processing (inverse dq transformation processing) and dual Phase/three-phase conversion processing (inverse αβ conversion processing) is performed to convert into three compensation signals. The stationary coordinate conversion process is the opposite of the rotating coordinate conversion process, and the two-phase/three-phase conversion process is the opposite of the three-phase/two-phase conversion process. The stationary coordinate conversion process is performed based on the internal value X _i (internal phase) input from the internal value generation unit 31. The command signal generation section 32 generates three command signals from the sine wave signal generated based on the internal value X _i input from the internal value generation section 31 and the three compensation signals, and generates three command signals from the PWM signal generation section. Output to 33. The command signal generation unit 32 controls the input voltage of the inverter circuit 2, but a description thereof will be omitted. In this embodiment, a case has been described in which the apparatus A is a three-phase system, but it may be a single-phase system. In the case of a single-phase system, the command signal generation unit 32 may control a single-phase voltage signal obtained by detecting the output voltage of the inverter circuit 2.

The PWM signal generation section 33 generates a PWM signal. The PWM signal generation section 33 generates a PWM signal using a triangular wave comparison method based on the carrier signal and the command signal inputted from the command signal generation section 32. For example, a pulse signal that becomes a high level when the command signal is greater than the carrier signal and becomes a low level when the command signal is less than or equal to the carrier signal is generated as a PWM signal. The generated PWM signal is output to the inverter circuit 2. Note that the configuration of the PWM signal generation section 33 is not limited.

The communication unit 34 communicates with other devices A. The communication unit 34 receives the internal value X _i generated by the internal value generation unit 31 and transmits it to the communication unit 34 of the other device A. Further, the communication unit 34 outputs the internal value X _j received from the communication unit 34 of another device A to the internal value generation unit 31. In this specification, the internal value received from the j-th device A among the other devices A is expressed as X _j . j is a natural number from 1 to n. Note that the communication method is not limited, and may be wired communication or wireless communication. In this embodiment, the timing at which the communication unit 34 transmits the internal value X _i to the other device A is different from that of the communication unit 34 of the other device A. In other words, the plurality of devices A making up the communication system B have different timings for transmitting their own internal values X _i to other devices A.

The internal value generation unit 31 generates and outputs an internal value X _i that changes over time. Further, the internal value generation section 31 updates the internal value X _i using the generated internal value X _i and the internal value X _j of another device A inputted from the communication section 34 . Even if the internal value X _i and the internal value X _j are different, the internal value X _i and the internal value X _j converge to the same value by repeating the update process in the internal value generation unit 31. As shown in FIG. 1B, the internal value generation section 31 includes a calculation section 311, an adder 313, and an integrator 314.

The calculation unit 311 subtracts the internal values X _i generated by the internal value generation unit 31 from each internal value X _j input from the communication unit 34, and adds a predetermined coefficient to the calculation result D _i obtained by adding all the subtraction results. It is multiplied by ε and outputted to the adder 313. The coefficient ε is a value that satisfies 0<ε<1/d _max and is set in advance. d _max is the largest number among all the devices A that make up the communication system B, out of d _i which is the number of other devices A with which the communication unit 34 communicates. The coefficient ε is multiplied in order to prevent the value added to the integrator 314 from becoming too large (small) and the variation in the internal value X _i from becoming too large.

The adder 313 adds the input from the calculation unit 311 and the predetermined angular frequency ω ₀ and outputs the result to the integrator 314 as a corrected angular frequency ω _i . The integrator 314 integrates the corrected angular frequency ω _i input from the adder 313 to generate and output an internal value X _i . The integrator 314 generates the internal value X _i by adding the modified angular frequency ω _i to the previously generated internal value X _i . Further, the integrator 314 outputs the internal value X _i as a value in the range of (-π<X _i ≦π). Note that the method of setting the range of the internal value X _i is not limited to this, and may be, for example, (0≦X _i <2π). Integrator 314 outputs internal value X _i to command signal generation section 32, communication section 34, and calculation section 311.

Each time the _{communication} unit 34 receives an internal value X _j from any device A, the _calculation unit 311 calculates the internal value The difference from the generated internal value X _i is calculated. The internal value X _i and the internal value X _j change over time, and the values at time t are written as X _i (t) and X _j (t), respectively. The calculation unit 311 sequentially calculates the difference (subtraction result) between the internal value X _j of another device A and the internal value X _i of the own device, and adds all these subtraction results every update period Δt, Multiply by the coefficient ε. In this embodiment, the update period Δt is divided into (n+1) time periods obtained by adding 1 to the number n of devices A (n=5 in the example of FIG. 1(a)), and each device A has a different time period. The internal value X _i is transmitted to other devices A, and each device A updates the internal value X _i in the last time period. That is, the communication unit 34 of each device A transmits the internal value X _i to the other device A at a different timing from that of the communication unit 34 of the other device A. Further, the internal value generation unit 31 of each device A updates the internal value X _i at an update timing different from the timing at which the communication unit 34 of each device A transmits. Although the update period Δt is not limited, it is, for example, about 1 second in this embodiment. In this case, in the example of FIG. 1(a), each time period is approximately (1/6) seconds.

For example, the device A1 transmits the internal value X ₁ (0) to the other device A at time t=0 (see FIG. 2(a)). The device A2 transmits the internal value X ₂ ((1/6)Δt) to the other device A at a timing of time t=(1/6)Δt (see FIG. 2(b)). The device A3 transmits the internal value X ₃ ((2/6)Δt) to the other device A at a timing of time t=(2/6)Δt (see FIG. 2(c)). Furthermore, device A4 transmits the internal value X ₄ ((3/6)Δt) to other device A at time t=(3/6)Δt, and device A5 transmits the internal value The internal value X ₅ ((1/6)Δt) is transmitted to the other device A at the timing of . Thereafter, at time t=(5/6)Δt, each device A performs addition of the subtraction results and multiplication by the coefficient ε, and updates the internal value X _i by adding the calculation results. Therefore, the internal value X _i of each device A is updated according to the calculation result every update period Δt.

Even during this update period Δt, the internal value X _i changes according to the passage of time and the angular frequency ω ₀ . That is, the internal value X _i generated by the internal value generation unit 31 of the device A is expressed by the following equation (1) and the following equation (2). Equation (1) below represents the calculation at the update timing. Equation (2) below represents calculation between update timings. The coefficient _aij is set to "1" or "0". The coefficient a _ij is set to "1" for the internal value X _j that the communication unit 34 receives, and the coefficient a _ij is set to "0" for the internal value X _j that is not received.

Note that the timing at which each device A transmits the internal value X _i to other devices A may not be at equal intervals. Furthermore, each device A may calculate and update the internal value X _i at the time when the last device A transmits the internal value X _i . In this case, the update period Δt is set to the number n of devices A. You can divide it into several time periods.

The internal value generation unit 31 updates the internal value X _i using the above equation (1) at every update period Δt. By performing this update in each device A, the internal values X _i of each device A converge to the same value. The internal value X _i changes with time, and can be thought of as a combination of a component that changes according to the angular frequency ω ₀ and a component that changes to compensate for the initial phase shift. As the latter converges to the same value X _α , the internal value X _i of each device A also converges to the same value. It has also been mathematically proven that the latter converges to the same value (see Non-Patent Documents 1 and 2). It has also been proven that the convergence value X _α is the arithmetic mean value of the initial values of the internal values X _i of each device A, as shown in equation (3) below. Equation (3) below indicates that the arithmetic average value is calculated by adding all the initial values of the internal values X ₁ to X _n of the devices A1 to An and dividing the sum by n.

FIG. 3 is a flowchart for explaining the process of updating the internal value X _i (X ₁ ) performed by the control circuit 3 of the device A1. The update process is executed every update cycle Δt.

First, the internal value _X1 is transmitted to another device A (S1). Next, it is determined whether the internal value _X2 of another device A (A2) has been received (S2). If the internal value _X2 has not been received (S2: NO), the process returns to step S2 and the determination in step S2 is repeated. If the internal value X ₂ is received (S2: YES), (X ₂ -X ₁ ) is calculated (S3). In this calculation, the internal value X ₁ at the time when the internal value X ₂ was received is used. Next, it is determined whether the internal value _X3 of another device A (A3) has been received (S4). If the internal value _X3 has not been received (S4: NO), the process returns to step S4 and the determination in step S4 is repeated. If the internal value X ₃ is received (S4: YES), (X ₃ -X ₁ ) is calculated (S5). In this calculation, the internal value X ₁ at the time when the internal value X ₃ was received is used.

Next, it is determined whether the internal value _X4 of another device A (A4) has been received (S6). If the internal value _X4 has not been received (S6: NO), the process returns to step S6 and the determination in step S6 is repeated. If the internal value X ₄ is received (S6: YES), (X ₄ -X ₁ ) is calculated (S7). In this calculation, the internal value X ₁ at the time when the internal value X ₄ was received is used. Next, it is determined whether the internal value _X5 of another device A (A5) has been received (S8). If the internal value _X5 has not been received (S8: NO), the process returns to step S8 and the determination in step S8 is repeated. If the internal value X ₅ is received (S8: YES), (X ₅ -X ₁ ) is calculated (S9). In this calculation, the internal value X ₁ at the time when the internal value X ₅ was received is used.

Next, it waits for a predetermined update timing (S10). In this embodiment, the update period Δt is divided into (n+1) time periods, which is the number n of devices A plus 1, and the last time period is used as the update timing, so from step S1 (transmission of internal value _X1 ) to ( The update timing is when n/(n+1))Δt has elapsed. When the update timing comes (S10: YES), the internal value _X1 is updated (S11). Specifically, the internal value generation unit 31 multiplies D _i , which is the sum of all the calculated values (subtraction results) in steps S3, S5, S7, and S9, by a coefficient ε, as shown in equation (1) above. The internal value X ₁ is updated by adding the calculation result and the value obtained by multiplying the update period Δt, which is the elapsed time since the previous update, by the angular frequency ω ₀ to the internal value X ₁ at the time of the previous update. . Note that the process of updating the internal value X _i (X ₁ ) performed by the control circuit 3 of the device A1 is not limited to that described above.

In this embodiment, a case has been described in which the control circuit 3 is implemented as a digital circuit, but it may also be implemented as an analog circuit. Alternatively, the computer may function as the control circuit 3 by designing a program to perform the processing performed by each section and executing the program. Alternatively, the program may be recorded on a recording medium and read by a computer.

Next, the effects of communication system B will be explained.

According to this embodiment, the internal value generation unit 31 updates the internal value X _{i using the generated internal value X i} and the internal value X _j of the other device A received by _the communication unit 34 . The internal value generation unit 31 of each device A similarly updates, so that the internal values X _i of all devices A converge to the same value. The communication unit 34 of a certain device A transmits the internal value X _i at a different timing from the communication unit 34 of another device A, so the timing of transmitting the internal value X i to the other device A is different from the timing of transmitting the internal value X _i to the other device A. The timing of receiving the internal value X _j from A can be shifted. As a result, the communication system B can improve the performance of each device A and the communication environment compared to the case where the communication unit 34 of each device A transmits the internal value X _i at the same timing as the communication unit 34 of other devices A. less affected by constraints.

Further, according to the present embodiment, when the communication unit 34 receives the internal value X _j from any device A, the calculation unit 311 calculates the internal value X _j and this time (when the internal value X _j is received). The difference between the internal value X _i generated by the internal value generation unit 31 is calculated. Therefore, in the communication system B, compared to the case where the calculation unit 311 of each device A calculates the difference between each internal value X _j and the internal value X _i received from all other devices A at once, It is less susceptible to constraints on the calculation performance of each device A.

Further, according to the present embodiment, the calculation unit 311 adds all the subtraction results and calculates the coefficient ε at an update timing that is different from the timing at which the communication unit 34 of each device A transmits (the timing at which each subtraction process is performed). Multiply. Further, the internal value generation unit 31 updates the internal value X _i based on the calculation result in the calculation unit 311 at the update timing. Therefore, communication system B is less susceptible to constraints on the computational performance of each device A.

Further, according to the present embodiment, the internal value X _i generated by the internal value generation unit 31 of each device A is constantly changing. Therefore, when calculating the difference between internal value X _j and internal value X _i , if the acquisition timings of internal value X _j and internal value X _i do not match, appropriate convergence may not occur. When the _{communication} unit 34 receives an internal value X _j from any device A _, the calculation unit 311 calculates the internal value The difference from the internal value X _i is calculated. Since the calculation unit 311 performs the subtraction based on the internal value X _i and the internal value X _j at the same time, the communication system B can appropriately converge the internal value X _i .

In the first embodiment, the component that changes to compensate for the initial phase shift of the internal value X _i of the device A is converged to the arithmetic mean value of the initial value of the internal value X _i of each device A. Although the description has been made regarding the case where the The convergence value X _α changes depending on the arithmetic expression set in the arithmetic unit 311. The arithmetic expression set in the arithmetic unit 311 is not limited.

In the first embodiment, each device A is a distributed power source, and the communication system B synchronizes the internal phases of the inverter devices of each device A (distributed power source) connected in parallel. The communication system according to the present invention is not limited to this. The present invention can be applied to any communication system that includes a device that has a communication function and matches internal values by transmitting and receiving internal values with other devices that constitute a network. For example, when various timings are made to match or are shifted so that they do not match, the present invention makes it possible to suppress the amount of output active power and output reactive power by matching the internal compensation values of each inverter device that constitutes the power system. It can also be applied to the case where each measuring device matches the internal average value, maximum value, and minimum value based on the measured value.

FIG. 4 is a diagram for explaining the communication system B' according to the second embodiment, and is a block diagram showing the internal configuration of each device A' forming the communication system B'. In the figure, the same or similar elements as those in the device A according to the first embodiment (see FIG. 1(b)) are given the same reference numerals. The communication system B' according to the second embodiment differs from the communication system B according to the first embodiment in that the internal value X _i generated by the internal value generation unit 31 of each device A' changes only when updated. Note that the diagram showing the communication status of the plurality of devices A' that constitute the communication system B' is the same as that of the first embodiment (see FIG. 1A), so description and explanation thereof will be omitted.

The device A' according to the second embodiment performs control based on the internal value X _i generated by the internal value generation section 31 and performs calculation using the internal value X _i . In actuality, the device A' has a control means for inputting the internal value X _i to perform control, a calculation means for performing calculations, a display means for displaying the internal value X _i , etc. However, in this embodiment, the description and explanation of these means are omitted.

The internal value generation section 31 of the device A' updates the internal value X _i using the generated internal value X _i and the internal value X _j of another device A' inputted from the communication section 34 . The internal value generation unit 31 does not change the internal value X _i according to time, but changes it only when updating. That is, the internal value X _i generated by the internal value generation unit 31 of the device A' is expressed by the following equation (4) and the following equation (5). Equation (4) below represents the calculation at the update timing. Equation (5) below represents calculation between update timings. u(kΔt) is a time-series change element, and is an element for adding the amount of change in the internal value X _i from t=kΔt to t=(k+1)Δt at the time of updating. For example, in the invention according to Patent Document 3, each measuring device calculates the overall average value by matching the internal values based on the measured values, but the measured value at the previous update and the measured value at the current update The difference is set as u(kΔt) and added to the internal value during the current update. In the case of the first embodiment, as shown in the above equation (1), u(kΔt)=ω ₀ *Δt, and as shown in the above equation (2), the internal value also changes between update timings. X _i changes.

Also in this embodiment, the internal value generation section 31 updates the internal value X _i using the generated internal value X _i and the internal value X _j of the other device A' received by the communication section 34 . The internal value generation unit 31 of each device A' similarly updates, so that the internal values X _i of all devices A' converge to the same value. Since the communication unit 34 of a certain device A' transmits the internal value X _i at a different timing from that of the communication unit 34 of another device A', the timing of transmitting the internal value X _i to the other device A', The timing of receiving the internal value X _j from another device A' can be shifted. As a result, in the communication system B', the communication unit 34 of each device A' transmits the internal value X _i at the same timing as the communication unit 34 of the other device A'. Less affected by performance and communication environment constraints. Further, the communication system B' has the same configuration as the communication system B, and thus has the same effects as the communication system B.

The communication system according to the present invention is not limited to the embodiments described above. The specific configuration of each part of the communication system according to the present invention can be changed in design in various ways.

A, A1 to A5, A': Device, 31: Internal value generation section, 34: Communication section, B, B': Communication system

Claims (5)

A communication system comprising a plurality of devices each having a communication function,
Each of the plurality of devices includes:
internal value generation means for generating an internal value;
communication means for communicating with at least one other device;
Equipped with
The communication means transmits the internal value generated by the internal value generation means to at least one of the other devices,
The internal value generation means updates the generated 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 timing at which the communication means transmits is different from the timing at which the communication means of the other device transmits,
A communication system characterized by: The internal value generation means, when the communication means receives an internal value from any of the other devices, calculates the difference between the received internal value and the internal value generated at this time, and obtains a subtraction result. ,
The communication system according to claim 1. The internal value generation means uses the subtraction result calculated between the previous update timing and the current update timing at an update timing different from the timing at which the communication means of each device transmits the generated value. update internal value,
The communication system according to claim 2. When the number of the plurality of devices is n and the cycle of the update timing is Δt,
The timing at which each communication means of the plurality of devices transmits is shifted by (Δt/(n+1)),
The communication system according to claim 3. The internal value generated by the internal value generating means is constantly changing.
A communication system according to any one of claims 1 to 4.

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