JP6397653B2 - Measuring device and calculation method - Google Patents

Description

  The present invention relates to a measuring apparatus capable of calculating a maximum value or a minimum value of measurement values measured at a plurality of locations, and a method for calculating a maximum value or a minimum value.

  In solar power plants and wind power plants, dozens to hundreds of inverter devices are connected in parallel and connected to the power system.

  FIG. 11 is a diagram for explaining a conventional solar power plant. A measurement value obtained by the measuring device A100 incorporated in each inverter device is input to the monitoring device E, and the monitoring device E monitors the operating state of each inverter device (for example, see Patent Document 1). The measurement values input to the monitoring device E include, for example, output active power, output reactive power, output voltage, output current of the inverter circuit C, input power from the solar cell connected to the inverter circuit C, input voltage, input There are current, amount of solar radiation to solar cell, solar cell temperature and so on. FIG. 11 shows a case where the measuring device A100 is an active power measuring device that is arranged on the output side of the inverter circuit C and measures the output active power. The monitoring device E monitors the power generation state based on the measurement value input from each measurement device A100. The monitoring device E can calculate the maximum value and the minimum value among the measurement values input from each measurement device A100.

JP 2012-235658 A

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 solar power plant, the inverter devices are scattered on a large site. The measuring device A100 built in each inverter device can know the measured value in the inverter device, but cannot know the maximum value or the minimum value among the measured values in all the inverter devices. In order to know the maximum value and the minimum value, it is necessary to refer to the monitoring device E.

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a method for calculating the overall maximum value or minimum value without collecting all measurement values. .

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

  The measurement device provided by the first aspect of the present invention is a measurement device that performs measurement at each of a plurality of locations, and includes an internal value generation unit that generates an internal value based on a measurement value, and at least one other A communication unit that communicates with a measurement device, wherein the communication unit transmits an internal value generated by the internal value generation unit to at least one of the other measurement devices, and the internal value generation unit includes: An internal value is generated 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 measuring devices, and the generation is performed when the measured value changes. An internal value is generated using the measured value instead of the internal value.

  The measurement device provided by the second aspect of the present invention is a measurement device that performs measurement at each of a plurality of locations, and includes an internal value generation unit that generates an internal value based on the measurement value, and at least one other A communication unit that communicates with a measurement device, wherein the communication unit transmits an internal value generated by the internal value generation unit to at least one of the other measurement devices, and the internal value generation unit includes: An internal value is generated 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 measuring devices, and the measurement value is changed when the measured value changes. A value is output as an internal value.

  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 subtracts the generated internal value from the received internal value, and adds only those whose subtraction result is a positive value. Calculate the result.

  In a preferred embodiment of the present invention, the calculation means subtracts the generated internal value from the received internal value, and adds only those whose negative result is a negative value. Calculate the result.

  In a preferred embodiment of the present invention, there is further provided display means for displaying the internal value generated by the internal value generating means.

  In a preferred embodiment of the present invention, there is further provided timing matching means for matching the timing at which the internal value generating means generates the internal value with the other measuring device.

  In a preferred embodiment of the present invention, the timing matching unit includes a timing phase generation unit that generates a timing phase, and the communication unit uses the timing phase generated by the timing phase generation unit as the other measurement device. And the timing phase generation means uses the calculation result based on the generated timing phase and the timing phase received by the communication means from at least one of the other measurement devices. Generate phase.

  In a preferred embodiment of the present invention, the active power is calculated based on a voltage sensor that detects a voltage, a current sensor that detects a current, a voltage signal detected by the voltage sensor, and a current signal detected by the current sensor. Active power calculation means for calculating the measured value is further provided.

  In a preferred embodiment of the present invention, a temperature sensor for detecting temperature is further provided, and the temperature detected by the temperature sensor is set as the measured value.

  The calculation method provided by the third aspect of the present invention is a method for calculating the maximum value or the minimum value of the measurement values measured in each measurement device arranged at a plurality of locations, and is based on the measurement values. A first step of generating an internal value, a second step of transmitting the internal value generated in the first step to at least one other measurement device, and an internal transmitted by at least one other measurement device A third step of receiving a value by each measuring device, and the first step uses a calculation result based on the generated internal value and the internal value received in the third step. Then, an internal value is generated, and when the measured value changes, the generated internal value is replaced with the measured value.

A calculation method provided by the fourth aspect of the present invention is a method for calculating a maximum value among internal values of a plurality of devices, the first step of generating the internal value, Each device performs a second step of transmitting the internal value generated in the first step to at least one other device and a third step of receiving the internal value transmitted by at least one other device. The first step is to integrate the operation result u _i calculated based on the following equation from the generated internal value X _i and the internal value X _j received in the third step. The internal value X _i is generated. However, alpha _ij is "1" when the X _j> X _i, is a function that becomes "0" when the X _j ≦ X _i.

A calculation method provided by a fifth aspect of the present invention is a method for calculating a minimum value among internal values of a plurality of devices, the first step of generating the internal value, Each device performs a second step of transmitting the internal value generated in the first step to at least one other device and a third step of receiving the internal value transmitted by at least one other device. The first step is to integrate the operation result u _i calculated based on the following equation from the generated internal value Y _i and the internal value Y _j received in the third step. The internal value Y _i is generated. However, β _ij is a function that is “1” when Y _j <Y _i , and “0” when Y _j ≧ Y _i .

  According to the present invention, the internal value generation unit generates an internal value using the calculation value based on the generated internal value, the internal value received by the other measurement device received by the communication unit, and the measurement value. When the internal value generating means of each measuring device does this, the internal values in all measuring devices converge to the same value. When the internal value generator calculates the internal value by subtracting the internal value generated from the received internal value and integrating the operation result obtained by adding all the positive values that are subtracted, the internal value Converges to the maximum measured value of each measuring device. Also, when the internal value generation means calculates the internal value by subtracting the internal value generated from the received internal value, and integrating the calculation result obtained by adding all of the subtraction results that are negative values, The internal value converges to the minimum value of the measurement value of each measurement device. Therefore, each measuring device can calculate the maximum value or the minimum value as a whole without collecting all the measured values measured at a plurality of locations.

  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 measuring device which concerns on 1st Embodiment. It is a figure which shows the solar power plant in which multiple inverter apparatuses were connected in parallel. 3 is a diagram illustrating an example of an internal configuration of an active power calculation unit 3. FIG. It is a flowchart for demonstrating the arithmetic processing which the calculating part 51 performs. It is a figure for _{demonstrating} the change of the internal maximum value Xi by the update of the measured active power. It is a figure for demonstrating the simulation which confirms that the maximum value is calculated in each measuring device. It is a figure for demonstrating the simulation which confirms that the minimum value is calculated in each measuring device. It is a figure for demonstrating the other communication state of each measuring device. It is a figure for demonstrating the measuring device which concerns on 2nd Embodiment. It is a figure for demonstrating the temperature measuring device which concerns on 3rd Embodiment. It is a figure for demonstrating the conventional solar power plant.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings, taking as an example the case where the measurement apparatus according to the present invention is used as a measurement apparatus for output active power.

  FIG. 1 is a diagram for explaining a measuring device A according to the first embodiment, and shows a state where the measuring device A is arranged on the output side of the inverter circuit C inside the inverter device linked to the power system B. Yes. FIG. 2 is a diagram showing a photovoltaic power plant in which a plurality of inverter devices are connected in parallel, and shows a state in which a measuring device A built in each inverter device is communicating.

  The inverter circuit C converts DC power input from a solar cell (not shown) into AC power and outputs the AC power to the power system B. The measuring device A measures the output active power of the inverter circuit C. The inverter circuit C, a control circuit that controls the inverter circuit C, a measuring device A, and an inverter device that includes various protection devices are so-called power conditioners.

  As shown in FIG. 1, the measuring device A includes a voltage sensor 1, a current sensor 2, an active power calculation unit 3, a maximum value generation unit 5, a display unit 6, and a communication unit 7. The measuring device A calculates the effective power P output from the inverter circuit C based on the voltage signal detected by the voltage sensor 1 and the current signal detected by the current sensor 2.

  The voltage sensor 1 is arranged on the output line of the inverter circuit C and detects an instantaneous value of the voltage at the arrangement position. The voltage sensor 1 digitally converts the detected instantaneous value and outputs it to the active power calculation unit 3 as a voltage signal. The current sensor 2 is arranged on the output line of the inverter circuit C and detects an instantaneous value of the current at the arrangement position. The current sensor 2 digitally converts the detected instantaneous value and outputs it to the active power calculation unit 3 as a current signal.

  The active power calculator 3 calculates the active power P based on the voltage signal input from the voltage sensor 1 and the current signal input from the current sensor 2. The active power calculation unit 3 updates the calculated active power P at a predetermined timing (for example, at intervals of 1 second), and outputs it to the maximum value generation unit 5 and the display unit 6.

  FIG. 3 is a diagram illustrating an example of an internal configuration of the active power calculation unit 3.

  The active power calculator 3 calculates the active power P based on the three-phase voltage signal and current signal. The αβ converters 31 and 31 ′, the dq converters 32 and 32 ′, and the power calculator 33 is provided.

  The αβ converter 31 converts the three-phase voltage signals Vu, Vv, Vw input from the voltage sensor 1 into two-phase voltage signals Vα, Vβ. The dq converter 32 receives the voltage signals Vα and Vβ from the αβ converter 31 and calculates an in-phase component Vd and a phase difference component Vq. The αβ converter 31 ′ converts the three-phase current signals Iu, Iv, Iw input from the current sensor 2 into two-phase current signals Iα, Iβ. The dq conversion unit 32 'receives the current signals Iα and Iβ from the αβ conversion unit 31' and calculates the in-phase component Id and the phase difference component Iq.

The power calculation unit 33 uses the in-phase component Vd and the phase difference component Vq input from the dq conversion unit 32 and the in-phase component Id and the phase difference component Iq input from the dq conversion unit 32 ′ to the following equation (1). Based on this, the active power P is calculated. The power calculation unit 33 calculates an average value between timings at a predetermined timing and outputs the average value as the active power P.

  Note that the active power calculation unit 3 illustrated in FIG. 3 is merely an example and is not limited thereto. For example, the active power P may be calculated from the voltage signals Vα, Vβ and the current signals Iα, Iβ, or the active power P may be calculated from the voltage signals Vu, Vv, Vw and the current signals Iu, Iv, Iw. It may be. The active power P may be calculated from the effective values of the voltage and current and the phase difference between the voltage and current.

The maximum value generation unit 5 generates an internal maximum value X _i of the active power P calculated by each measuring device A. The internal maximum value X _i is the maximum value of the active power P calculated by each measuring device A, which is temporarily calculated inside each measuring device A. As will be described later, the internal maximum value X _i of each measuring device A converges to the maximum value of the active power P calculated by each measuring device A by repeating the arithmetic processing in the maximum value generating unit 5. The maximum value generation unit 5 outputs the generated internal maximum value X _i to the display unit 6 and the communication unit 7. Details of the maximum value generator 5 will be described later.

The display unit 6 displays the measured value, and displays the active power P input from the active power calculation unit 3 as the output active power of the inverter circuit C. The display unit 6 displays the internal maximum value X _i input from the maximum value generation unit 5 as the maximum value of the output active power of the inverter device installed in the power plant.

The communication unit 7 communicates with another measuring device A. The communication unit 7 receives the internal maximum value X _i generated by the maximum value generation unit 5 and transmits it to the communication unit 7 of another measuring apparatus A. In addition, the communication unit 7 outputs the internal maximum value X _j received from the communication unit 7 of the other measuring device A to the maximum value generation unit 5. Note that the communication method is not limited, and may be wired communication or wireless communication.

  As shown in FIG. 2, each measuring device A is arranged on the output side of the inverter circuit C inside the inverter device linked to the power system B. FIG. 2 shows a state where five inverter devices are connected to the power system B. In practice, more inverter devices are connected, but extremely few cases are shown for simplification of explanation.

  The solid arrows shown in FIG. 2 indicate that the measurement apparatuses A are communicating with each other. The measurement device A1 performs mutual communication only with the measurement device A5 and the measurement device A2, and the measurement device A2 performs mutual communication only with the measurement device A1 and the measurement device A3. Further, the measuring device A3 performs mutual communication only with the measuring device A2 and the measuring device A4, the measuring device A4 performs mutual communication only with the measuring device A3 and the measuring device A5, and the measuring device A5 includes the measuring device A4 and the measuring device A4. Mutual communication is performed only with the measuring apparatus A1. As described above, the measuring device A communicates with at least one measuring device A among the measuring devices A built in the respective inverter devices installed in the power plant. On the other hand, it is only necessary to have a communication path (hereinafter, this state is referred to as “connected state”), and it is not necessary to communicate with all the measuring apparatuses A.

For example, when the measurement device A is the measurement device A2, the communication unit 7 transmits the internal maximum value X ₂ generated by the maximum value generation unit 5 to the communication unit 7 of the measurement devices A1 and A3, and the communication unit of the measurement device A1 7 receives the internal maximum value X ₁ and receives the internal maximum value X ₃ from the communication unit 7 of the measuring device A 3.

  Next, details of the maximum value generation unit 5 will be described.

Maximum value generation unit 5 includes an internal maximum value X _i of the generated, it is input from the communication unit 7, by using the internal maximum value X _j of the other measuring device A, to generate an internal maximum value X _i. Even if the internal maximum value X _i is different from the internal maximum value X _j , the internal maximum value X _i and the internal maximum value X _j become a common value by repeating the arithmetic processing in the maximum value generation unit 5. Converge. As shown in FIG. 1, the maximum value generation unit 5 includes a calculation unit 51, a multiplier 52, and an integrator 54.

The calculation unit 51 performs a calculation based on the following equation (2). alpha _ij is "1" when the X _j> X _i, is a function that becomes "0" when the X _j ≦ X _i. That is, the calculation unit 51 subtracts the internal maximum value X _i generated by the maximum value generation unit 5 from each internal maximum value X _j input from the communication unit 7, and only the subtraction result is a positive value. An operation result u _i obtained by adding all of the above is output to the multiplier 52. However, when the active power P input from the active power calculation unit 3 changes, the calculation result using the active power P instead of the internal maximum value X _i (that is, X _i = P in (2) below) u _i is calculated.

For example, when the measuring device A is the measuring device A2 (see FIG. 2) and the active power P does not change and X ₁ > X ₂ > X ₃ , the calculation unit 51 uses the following equation (3): An operation is performed and an operation result u ₂ is output.

  FIG. 4 is a flowchart for explaining a calculation process performed by the calculation unit 51. The calculation process is started when the measuring apparatus A is activated.

First, the internal maximum value X _i generated last time by the maximum value generation unit 5, the internal maximum value X _j of another measuring device A input from the communication unit 7, and the effective power input from the active power calculation unit 3 The power P is acquired (S1), and it is determined whether or not the active power P has been updated (S2). When the active power P is updated (S2: YES), the active power P is input to the internal maximum value X _i (S3). If the active power P has not been updated (S2: NO), the internal maximum value X _i remains unchanged, and the process proceeds to step S4.

Next, the calculation result u _i is initialized to “0” (S4), and steps S6 and S7 are repeated for all internal maximum values X _j (S5, S5 ′). Only when the internal maximum value X _j is larger than the internal maximum value X _i (S6: YES), a value obtained by subtracting the internal maximum value X _i from the internal maximum value X _j is added to the operation result u _i (S7).

After steps S6 and S7 are repeated for all internal maximum values X _j (S5, S5 ′), the calculation result u _i is output (S8), and the process returns to step S1. In addition, the calculation process which the calculating part 51 performs is not limited to what was mentioned above. For example, if it is determined in step S2 that the active power P has been updated (S2: YES), the integrator 54 outputs instead of using the active power P as the internal maximum value X _i in the calculation in the calculation unit 51. The internal maximum value X _i may be set to the active power P (that is, instead of step S3, the active power P is output from the integrator 54 as the internal maximum value X _i and the process returns to step S1).

The multiplier 52 multiplies the calculation result u _i input from the calculation unit 51 by a predetermined coefficient ε and outputs the result to the integrator 54. The coefficient ε is a value that satisfies 0 <ε <1 / d _max and is set in advance. d _max is the _maximum of all the measuring devices A built in each inverter device installed in the power plant among _di , which is the number of other measuring devices A with which the communication unit 7 communicates. It is. That is, it is the number of internal maximum values X _j input to the communication unit 7 of the measuring device A that communicates with the largest number of other measuring devices A. Note that the coefficient ε is multiplied by the calculation result u _i in order to suppress the fluctuation of the internal maximum value X _{i from} becoming too large. Therefore, when the process in the average value generator 5 is a continuous time process, the multiplier 52 need not be provided.

The integrator 54 integrates the value input from the multiplier 52 (that is, adds the value input from the multiplier 52 to the previously generated internal maximum value X _i ) to generate the internal maximum value X _i. Output. The internal maximum value X _i is output to the display unit 6, the communication unit 7, and the calculation unit 51.

In the present embodiment, the maximum value generation unit 5 uses the generated internal maximum value X _i and the internal maximum value X _j of another measuring device A input from the communication unit 7 to use the internal maximum value X _i. Is generated. When the internal maximum value X _i is smaller than any of the internal maximum values X _j , the difference is added to increase the internal maximum value X _i . As a result, the internal maximum value X _i approaches the maximum value of the internal maximum value X _j . When the internal maximum value X _i matches the maximum value of the internal maximum value X _j , the calculation result u _i becomes “0” and the calculation result u _i does not change. However, since this process is performed in each measuring device A, if there is a larger internal maximum value, any one of the internal maximum values X _j changes to match the internal maximum value, and the internal maximum value X _i also matches the internal maximum value X _j . Therefore, the internal maximum value X _i converges to the overall maximum value. When the active power P of any measuring device A is updated, the internal maximum value X _i of the measuring device A is replaced with the updated active power P, and the internal maximum value X _i of each measuring device A is It converges to a new maximum value.

FIG. 5 is a diagram for explaining a change in the internal maximum value X _i due to the update of the active power P.

In FIG. 5, the case where the maximum values of the two measuring devices A1 and A2 are calculated will be described. The active power P measured by the measuring device A1 and A2 and P ₁ and P ₂ respectively show generated at the maximum value generation portion 5 of the measuring apparatus A1 and A2 internal maximum value as X ₁ and X _2, respectively . P ₁ is “40” from time t 0 to t ₁ , “35” from time t 1 to t ₂ , “40” after time t ₂ , and P ₂ is “20” from time t 0 to t 1, The time from t1 to t2 is “30”, and after time t2 is “45”.

X ₁ and X ₂ are “40” and “20”, respectively, at time t 0, but X ₂ immediately changes to “40”. Thereafter, at time t1, P ₁ is updated to “35”, so X ₁ is updated to “35”. Since P ₂ is updated to “30”, X ₂ is updated to “30”, but immediately changes to “35”. At time t2, since P ₂ is updated to “45”, X ₂ is updated to “45”. Also, since P ₁ is updated to “40”, X ₁ is updated to “40”, but immediately changes to “45”.

  Below, the simulation which confirms that each measuring apparatus A1-A5 shown in FIG. 2 calculates a maximum value is demonstrated.

  FIG. 6 is a diagram for explaining the simulation. FIG. 6A shows the change over time of the active power P (that is, the measured value) output from the active power calculation unit 3 of each of the measuring devices A1 to A5. Each measurement value is randomly changed every second using a random number. The communication cycle by the communication unit 7 is 10 milliseconds, and ε is 1/3.

FIG. 5B shows the change over time of the internal maximum value X _i output from the maximum value generation unit 5 of each of the measuring devices A1 to A5. As shown in FIG. 5B, when the measurement value is updated, the internal maximum value X _i of each of the measuring devices A1 to A5 changes transiently, but it can be confirmed that it has converged to the maximum value. If the internal maximum value X _i is displayed on the display unit 6 after the steady state is reached (for example, 0.1 seconds after the measurement value is updated), the maximum value as a whole can be displayed. it can.

According to the present embodiment, the measuring device A built in each inverter device installed in the power plant has at least one measuring device A (for example, one that is located in the vicinity or one that has established communication). Since mutual communication is performed and the communication state of each measuring device A is in the connected state, the internal maximum values X _i of all the measuring devices A converge to the same value. The convergence value is the maximum value of the internal maximum value X _i of each measuring device A. When the active power P is updated, the internal maximum value X _i is replaced with the updated active power P, and the internal maximum value X _i converges to a new maximum value. When the active power P of another measuring device A is updated, the internal maximum value X _i of the measuring device A is replaced with the updated active power P, and the internal maximum value X _i of each measuring device A is It converges to a new maximum value. Thereby, the internal maximum value X _i can calculate the maximum value of the active power P of each measuring device A. The display unit 6 displays the internal maximum value X _i . Therefore, without referring to the monitoring device E, each measuring device A can know the maximum value of the output active power in the entire power plant.

  In addition, in the said 1st Embodiment, although the case where the measuring device A calculated the maximum value was demonstrated, it is not restricted to this. It is also possible for the measuring device A to calculate the minimum value.

In order for the measurement apparatus A to calculate the minimum value instead of the maximum value, the calculation process in the calculation unit 51 may be changed. Here, the minimum value generation unit 5 ′ uses the generated internal minimum value Y _i and the internal minimum value Y _j of another measuring device A input from the communication unit 7 to calculate the internal minimum value Y _i . The case of generating will be described. Note that the configuration of the measuring apparatus A in this case is the same as that shown in FIG. 1, and only the calculation process in the calculation unit 51 is changed. Since the maximum value generation unit 5 shown in FIG. 1 generates the internal maximum value, here, the maximum value generation unit 5 will be described as the minimum value generation unit 5 ′ that generates the internal minimum value.

The calculation unit 51 of the minimum value generation unit 5 ′ performs a calculation based on the following equation (4). β _ij is a function that is “1” when Y _j <Y _i , and “0” when Y _j ≧ Y _i . That is, the calculation unit 51 subtracts the internal minimum value Y _i generated by the minimum value generation unit 5 ′ from each internal minimum value Y _j input from the communication unit 7, and the subtraction result is a negative value. The result u _i obtained by adding all the above is output to the integrator 54. However, when the active power P input from the active power calculation unit 3 changes, the calculation result using the active power P instead of the internal minimum value Y _i (that is, Y _i = P in (4) below) u _i is calculated.

  Hereinafter, a simulation for confirming that the minimum value is calculated in each of the measurement apparatuses A1 to A5 illustrated in FIG. 2 will be described.

  FIG. 7 is a diagram for explaining the simulation. FIG. 6A is common to FIG. 6A, and shows the time change of the active power P (that is, the measured value) output by the active power calculation unit 3 of each of the measuring devices A1 to A5.

FIG. 7B shows a time change of the internal minimum value Y _i output from the minimum value generation unit 5 ′ of each of the measuring devices A1 to A5. As shown in FIG. 5B, when the measurement value is updated, the internal minimum value Y _i of each of the measuring devices A1 to A5 changes transiently, but it can be confirmed that it has converged to the minimum value. If the internal minimum value Y _i is displayed on the display unit 6 after the steady state is reached (for example, 0.1 seconds after the measurement value is updated), the overall minimum value can be displayed. it can.

  Note that both the maximum value generation unit 5 and the minimum value generation unit 5 ′ may be provided so that the measurement apparatus A can calculate the maximum value and the minimum value.

In the first embodiment, the case where each measuring device A performs mutual communication has been described. However, the present invention is not limited to this, and one-side communication may be performed. For example, as shown in FIG. 8, the measuring device A1 only receives from the measuring device A5, transmits only to the measuring device A2, and the measuring device A2 only receives from the measuring device A1 to the measuring device A3. Transmitting only, measuring device A3 only receiving from measuring device A2, only transmitting to measuring device A4, measuring device A4 only receiving from measuring device A3, only transmitting to measuring device A5 Even when the measurement apparatus A5 only receives from the measurement apparatus A4 and only transmits to the measurement apparatus A1, the internal maximum value X _i can be converged to the maximum value. More generally speaking, the internal maximum value is a state (a “strongly connected” state in the graph theory) that can reach the arbitrary measuring device A by following the transmission destination from the arbitrary measuring device A. This is a condition for converging X _i to the maximum value.

In the first embodiment, is not mentioned about the timing of the maximum value generation unit 5 generates an internal maximum value X _i, the generation timing of the internal maximum value X _i of the maximum value generation unit 5 of the measuring device A Are preferably matched.

If the generation timing of the internal maximum value X _i in the maximum value generation unit 5 of each measuring device A does not match, the error between the convergence value of the internal maximum value X _i and the actual maximum value may increase. Therefore, in order to suppress the occurrence of a large error, it is necessary to match the generation timing of the internal maximum value X _i in the maximum value generation unit 5 of each measuring device A. As a method of matching the generation timing of the internal maximum value X _i , for example, there is a method of using time information of GPS (Global Positioning System). That is, the maximum value generator 5 of each measuring device A may generate the internal maximum value X _i at the same timing using GPS time information. In addition, there is a method in which each measurement device A generates a timing phase for generation timing and matches this timing phase with the same phase.

FIG. 9 is a diagram for explaining a measuring apparatus A according to the second embodiment. In the figure, the same or similar elements as those of the measuring apparatus A (see FIG. 1) according to the first embodiment are denoted by the same reference numerals. The measuring apparatus A according to the second embodiment further includes a timing phase generation unit 8 and a timing generation unit 9, and a point that the communication unit 7 transmits and receives the timing phase θ _i in addition to the internal maximum value X _i. Thus, it is different from the measuring apparatus A according to the first embodiment.

The timing phase generator 8 generates a timing phase θ _i for instructing the generation timing of the internal maximum value X _{i in} the maximum value generator 5. The timing phase generation unit 8 outputs the generated timing phase θ _i to the communication unit 7 and the timing generation unit 9. Timing phase generator 8, a timing phase theta _i which generated, is input from the communication unit 7, by using the timing phase theta _j of another measuring device A, and generates a timing phase theta _i. Even if the timing phase θ _i is different from the timing phase θ _j , the timing phase θ _i and the timing phase θ _j converge to a common timing phase by repeating the arithmetic processing in the timing phase generator 8. As shown in FIG. 9, the timing phase generation unit 8 includes a calculation unit 81, a multiplier 82, an adder 83, and an integrator 84.

The calculation unit 81 performs a calculation based on the following equation (5). That is, the calculation unit 81 subtracts the timing phase θ _i generated by the timing phase generation unit 8 from each timing phase θ _j input from the communication unit 7 and adds the calculation result u ′ _i obtained by adding all the subtraction results. Output to the multiplier 82.

The multiplier 82 multiplies the operation result u ′ _i input from the operation unit 81 by a predetermined coefficient ε ′ and outputs the result to the adder 83. The coefficient ε ′ is a value that satisfies 0 <ε ′ <1 / d _max and is set in advance. Note that the coefficient ε ′ is multiplied by the operation result u ′ _i in order to prevent the correction angular frequency ω _i from becoming too large (small) and the variation of the timing phase θ _{i from} becoming too large. . Therefore, when the processing in the timing phase generator 8 is continuous time processing, the multiplier 82 need not be provided.

The adder 83 adds the input from the multiplier 82 to a predetermined angular frequency ω ₀ and outputs the result to the integrator 84 as a corrected angular frequency ω _i . The angular frequency ω ₀ corresponds to the timing frequency. The integrator 84 integrates the corrected angular frequency ω _i input from the adder 83 to generate and output the timing phase θ _i . The integrator 84 generates a timing phase theta _i by adding the corrected angular frequency omega _i in timing phase theta _i previously generated. The integrator 84 outputs the timing phase θ _i as a value in the range of (−π <θ _i ≦ π). The method of setting the range of the timing phase θ _i is not limited to this, and may be, for example, (0 ≦ θ _i <2π). The timing phase θ _i is output to the timing generation unit 9, the communication unit 7, and the calculation unit 81.

In the second embodiment, the timing phase generator 8, by using the timing phase theta _i which generated, is input from the communication unit 7, and a timing phase theta _j of another measuring device A, generates a timing phase theta _i To do. When the timing phase θ _i is larger than the arithmetic mean value of each timing phase θ _j , the calculation result u ′ _i output from the calculation unit 81 is a negative value. Then, the corrected angular frequency ω _i becomes smaller than the predetermined angular frequency ω _{0 and} the change amount of the timing phase θ _i becomes small. On the other hand, when the timing phase θ _i is smaller than the arithmetic mean value of each timing phase θ _j , the calculation result u ′ _i output from the calculation unit 81 is a positive value. Then, the corrected angular frequency ω _i becomes larger than the predetermined angular frequency ω ₀ , and the change amount of the timing phase θ _i becomes large. That is, the timing phase θ _i approaches the arithmetic average value of each timing phase θ _j . By performing this processing in each measuring device A, the timing phase θ _i of each measuring device A converges to the same value. The timing phase θ _i changes with time, and can be considered as a combination of a component that changes according to the angular frequency ω ₀ and a component that changes so as to compensate for the initial phase shift. As the latter converges to the same value θα, the timing phase θ _i of each measuring device A also converges to the same value. It has been proved mathematically that the latter converges to the same value θα (see Non-Patent Documents 1 and 2). Further, the convergence value θα is, as shown in the following equation (6), has also been demonstrated to be the arithmetic mean value of the initial value of the timing phase theta _i of the measuring device A. n is the number of inverter devices installed in the power plant (that is, the number of measuring devices A), and the following equation (6) adds all initial values of the timing phases θ _{1 to} θ _n of the measuring devices A _{1 to} An. The arithmetic mean value divided by n is calculated.

In the second embodiment, the case where the processing period T in the timing phase generation unit 8 is 1 second is described. When the period T is 0.1 seconds, for example, the input from the multiplier 82 is added by the adder 83 to a _{value obtained} by reducing the angular frequency ω ₀ to 1/10 (multiplied by 0.1). That is, Tω ₀ is input instead of ω ₀ .

The timing generation unit 9 outputs a timing signal that instructs the generation value of the internal maximum value X _i to the maximum value generation unit 5. The timing generator 9 outputs a timing signal based on the timing phase θ _i input from the timing phase generator 8. Specifically, the timing signal is output at the timing when the timing phase θ _i becomes “0”. The timing for outputting the timing signal is not limited to “0”. In addition, the timing signal may be output at a timing when the number of times the timing phase θ _i becomes “0” becomes a predetermined number. In addition, the timing generation unit 9 also outputs a timing signal that is frequency-divided according to each processing cycle to the active power calculation unit 3 and the communication unit 7.

According to the second embodiment, each measuring device A performs mutual communication with at least one measuring device A, and since the communication state of each measuring device A is a connected state, the timing phases θ _i of all the measuring devices A are Converge to the same value. Therefore, each measuring device A can match the generation timing of the internal maximum value X _{i in} the maximum value generation unit 5. Thereby, each measuring device A can converge the internal maximum value X _i to the actual maximum value with high accuracy. Each measuring device A can also match the timing of the active power calculation in the active power calculation unit 3 and the timing of the communication in the communication unit 7.

In the second embodiment, the varying components so as to compensate for deviation of the initial phase of the timing phase theta _i of the measuring device A, the arithmetic mean value of the initial value of the timing phase theta _i of the measuring device A Although the case where it makes it converge was demonstrated, it is not restricted to this. The convergence value θα varies depending on the calculation formula set in the calculation unit 81.

For example, when the calculation formula set in the calculation unit 81 is the following formula (7), the convergence value θα is a value as shown in the following formula (8). d _i is the number of other measuring devices A with which the communication unit 7 communicates, that is, the number of timing phases θ _j input to the communication unit 7. That is, the convergence value θα performed a weighting by number of the communication partner, a weighted average value of the initial value of the timing phase theta _i of the measuring device A.

Further, when the calculation formula set in the calculation unit 81 is the following formula (9), the convergence value θα is the geometric mean value of the initial values of the timing phase θ _i of each measuring device A as shown in the following formula (10). (Geometric mean value).

Further, when the calculation formula set in the calculation unit 81 is the following formula (11), the convergence value θα is the harmonic mean value of the initial values of the timing phase θ _i of each measuring device A as shown in the following formula (12). become.

Further, when the calculation formula set in the calculation unit 81 is the following formula (13), the convergence value θα is the P-order average of the initial values of the timing phase θ _i of each measuring device A as shown in the following formula (14). Value.

Further, using the algorithm for calculating the maximum value (or minimum value) described in the calculation unit 51 according to the first embodiment, the convergence value θα is set to the maximum value of the initial value of the timing phase θ _i of each measuring device A. (Or minimum value).

When the calculation formula set in the calculation unit 81 is the following formula (15), the convergence value θα is the maximum initial value of the timing phase θ _i of each measuring device A. Incidentally, alpha _ij is "1" when the θ _j> θ _i, is a function that becomes "0" when the θ _j ≦ θ _i.

Similarly, when the operation expression to set the calculation unit 81 had the following expression (16), the convergence value θα is minimized value of the initial value of the timing phase theta _i of the measuring device A. Β _ij is a function that is “1” when θ _j <θ _i , and “0” when θ _j ≧ θ _i .

  As described above, the algorithm for calculating the maximum value (or minimum value) described above is used not only for calculating the maximum value (or minimum value) but also for matching the phase, timing, and other internal values. Can also be used.

  In the said 1st and 2nd embodiment, although the case where the measuring apparatus A calculated the maximum value (or minimum value) of output active power was demonstrated, it is not restricted to this. For example, if reactive power is calculated instead of calculating active power by the active power calculation unit 3, the measuring device A functions as a reactive power measuring device that can calculate the maximum value (or minimum value) of output reactive power. Can be made. Further, the output voltage and output current of the inverter circuit C may be measured to calculate the maximum value (or minimum value), or the input power and input from the solar cell connected to the inverter circuit C The maximum value (or the minimum value) may be calculated by measuring the voltage and the input current. Alternatively, the maximum value (or minimum value) may be calculated by detecting the voltage phase and frequency from the voltage signal. Alternatively, the maximum value (or the minimum value) may be calculated by measuring the solar radiation intensity, the amount of solar radiation, the temperature of the solar battery, and the like. Furthermore, some or all of these measured values may be calculated respectively.

  In the said 1st and 2nd embodiment, although the case where the measuring device A was installed in the inverter apparatus installed in a solar power plant and connected to a solar cell was demonstrated, it is not restricted to this. For example, the present invention can be applied to a measuring device built in an inverter device installed in a wind power plant. In this case, the maximum value (or the minimum value) may be calculated by measuring the wind speed or the air volume. Further, the present invention can also be applied to a measuring device that is arranged on a power distribution line or power transmission line, or an outlet of each home or building and measures electrical information (voltage, current, power, etc.). The present invention can also be applied to measuring devices that measure electrical information of outputs such as fuel cells, storage batteries, diesel engine generators, and micro gas turbine generators.

  In addition, the present invention can be applied to a measuring device that measures information other than electrical information (for example, in addition to the above-described temperature, solar radiation intensity, solar radiation amount, wind speed, air volume, as well as atmospheric pressure, flow rate, weight, etc.). it can. The case where the measuring device A functions as a temperature measuring device will be described below as a third embodiment.

  FIG. 10 is a view for explaining a measuring apparatus (temperature measuring apparatus) A ′ according to the third embodiment. In the figure, the same or similar elements as those of the measuring apparatus A (see FIG. 1) according to the first embodiment are denoted by the same reference numerals. The temperature measurement device A ′ according to the third embodiment is different from the voltage sensor 1, the current sensor 2, and the active power calculation unit 3 in that the temperature measurement device A ′ includes the temperature sensor 1 ′, and the measurement device A according to the first embodiment. Different.

The temperature sensor 1 ′ detects the temperature T at the arrangement position, and uses, for example, a thermistor or a thermocouple. The detected temperature T is output to the maximum value generation unit 5 and the display unit 6. The maximum value generation unit 5 generates an internal maximum value X _i and performs transmission / reception with another temperature measurement device A ′ via the communication unit 7.

Also in the third embodiment, each temperature measurement device A ′ is in mutual communication with at least one temperature measurement device A ′, and all the temperatures are measured if the communication state of each temperature measurement device A ′ is a connected state. The internal maximum value X _i of the measuring device A ′ can be converged to the actual maximum value. Therefore, the maximum temperature measured by each temperature measuring device A ′ can be displayed on the display unit 6. In the third embodiment, the same effect as that of the first embodiment can be obtained.

  In the first to third embodiments, the case where the measuring device A uses the algorithm for calculating the maximum value (or the minimum value) has been described. However, the present invention is not limited to this. The algorithm (a method for calculating the maximum value (or minimum value)) can also be used in other apparatuses. For example, in each inverter device of a photovoltaic power plant, the output active power of each inverter device may be controlled to the maximum active power using the algorithm in a control circuit that controls the inverter circuit. The algorithm may be used not to calculate the maximum value (or minimum value) but to match the phase, timing, other internal values, and the like. For example, you may make it synchronize the internal phase of a control circuit using the said algorithm with the control circuit of each inverter apparatus of a photovoltaic power plant.

  The measurement apparatus and calculation method according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the measurement apparatus and calculation method according to the present invention can be varied in design in various ways.

A, A1 to A5 Measuring device A ′ Temperature measuring device 1 Voltage sensor 1 ′ Temperature sensor 2 Current sensor 3 Active power calculation unit 31, 31 ′ αβ conversion unit 32, 32 ′ dq conversion unit 33 Power calculation unit 5 Maximum value generation unit (Internal value generation means)
5 'Minimum value generator (internal value generator)
51 arithmetic unit 54 integrator 6 display unit 7 communication unit 8 timing phase generation unit (timing matching means)
81 arithmetic unit 82 multiplier 83 adder 84 integrator 9 timing generation unit (timing matching means)
B Power system C, C1 to C5 Inverter circuit E Monitoring device

Claims (13)

A measuring device that performs measurement at a plurality of locations,
An internal value generating means for generating an internal value based on the measured value;
Communication means for communicating with at least one other measuring device;
With
The communication means transmits the internal value generated by the internal value generation means to at least one of the other measurement devices;
The internal value generation means includes
Using the calculation result based on the generated internal value and the internal value received by the communication means from at least one of the other measuring devices, an internal value is generated,
When the measurement value changes, the internal value is generated using the measurement value instead of the generated internal value ,
The generated internal value is a maximum value or a minimum value.
A measuring device characterized by that. A measuring device that performs measurement at a plurality of locations,
An internal value generating means for generating an internal value based on the measured value;
Communication means for communicating with at least one other measuring device;
With
The communication means transmits the internal value generated by the internal value generation means to at least one of the other measurement devices;
The internal value generation means includes
Using the calculation result based on the generated internal value and the internal value received by the communication means from at least one of the other measuring devices, an internal value is generated,
When the measurement value changes, the measurement value is output as an internal value ,
The generated internal value is a maximum value or a minimum value.
A measuring device characterized by that. 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 measuring device according to claim 1 or 2. The calculation means subtracts the generated internal value for each received internal value , and calculates only the calculation result by adding all subtraction results whose subtraction result is a positive value .
The generated internal value is the maximum value.
The measuring device according to claim 3. The calculation means subtracts the generated internal value for each received internal value , and calculates the calculation result by adding all of the subtraction results for which the subtraction result is a negative value .
The generated internal value is the minimum value,
The measuring device according to claim 3. A display unit for displaying the internal value generated by the internal value generation unit;
The measuring device according to claim 1. A timing matching means for matching the timing at which the internal value generating means generates an internal value with the other measuring device;
The measuring device according to claim 1. The timing matching means includes timing phase generation means for generating a timing phase,
The communication unit transmits the timing phase generated by the timing phase generation unit to at least one of the other measurement devices;
The timing phase generation unit generates a timing phase using a calculation result based on the generated timing phase and a timing phase received by the communication unit from at least one of the other measurement devices.
The measuring device according to claim 7. A voltage sensor for detecting the voltage;
A current sensor for detecting current;
Based on the voltage signal detected by the voltage sensor and the current signal detected by the current sensor, active power calculating means for calculating active power as the measured value;
Further equipped with,
The measuring device according to claim 1. A temperature sensor for detecting the temperature;
The temperature detected by the temperature sensor is the measured value,
The measuring device according to claim 1. A method of calculating a maximum value or a minimum value of measurement values measured in each measurement device arranged in a plurality of locations,
A first step of generating an internal value based on the measured value;
A second step of transmitting the internal value generated in the first step to at least one other measuring device;
A third step of receiving an internal value transmitted by at least one other measuring device;
Is performed by each measuring device to converge the generated internal value to the maximum value or the minimum value ,
The first step includes
Using the calculation result based on the generated internal value and the internal value received in the third step, an internal value is generated,
When the measurement value changes, the generated internal value is replaced with the measurement value.
A calculation method characterized by the above. A method of calculating a maximum value among internal values of a plurality of devices,
A first step of generating the 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 by each device to converge the generated internal value to the maximum value ,
The first step integrates a calculation result u _i calculated based on the following equation from the generated internal value X _i and the internal value X _j received in the third step, thereby obtaining an internal value X generate _i ,
A calculation method characterized by the above.
However, alpha _ij is "1" when the X _j> X _i, is a function that becomes "0" when the X _j ≦ X _i.
A method of calculating a minimum value among internal values of a plurality of devices,
A first step of generating the 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 by each device to converge the generated internal value to the minimum value ,
The first step integrates the operation result u _i calculated based on the following equation from the generated internal value Y _i and the internal value Y _j received in the third step, thereby obtaining the internal value Y generate _i ,
A calculation method characterized by the above.
However, β _ij is a function that is “1” when Y _j <Y _i , and “0” when Y _j ≧ Y _i .