JP6189188B2 - Control circuit for controlling inverter circuit, inverter device provided with the control circuit, power system provided with the inverter device, and control method - Google Patents

Description

  The present invention relates to a control circuit that controls an inverter circuit, an inverter device that includes the control circuit, a power system that includes the inverter device, and a control method.

  2. Description of the Related Art Conventionally, an inverter device has been developed that converts DC power generated by a solar cell or the like into AC power and supplies it to an electric power system. When distributed power sources with unstable output such as photovoltaic power generation are introduced into a power system in large quantities, the frequency tolerance of the power system is lowered and frequency fluctuations frequently occur. Conventionally, as countermeasures against such system frequency fluctuations, countermeasures such as governor-free operation on the generator side have been performed. However, the countermeasures on the generator side alone are not sufficient, and the active power is optimally adjusted using the coordinated operation of the inverter device for the distributed power source and the inverter device for the storage battery system and the load whose load can be adjusted. It is necessary to suppress system frequency fluctuations.

  FIG. 14 is a diagram showing a power system in which a plurality of inverter devices A ′ linked to the power system B adjust active power to suppress system frequency fluctuations. In the figure, an inverter device A ′ for a distributed power source such as solar power generation or wind power generation, and an inverter device A ′ for a load that can be adjusted with a storage battery system are connected to a power system B.

  The monitoring device C is for centrally monitoring each inverter device A '. When the system frequency rises, the monitoring device C causes the inverter device A ′ for the distributed power source to suppress the output active power, increases the consumption amount to the inverter device A ′ for the load, and the inverter device A for the storage battery system. Increase the amount of charge (or decrease the amount of discharge). Further, when the system frequency is lowered, the consumption amount is decreased in the load inverter device A ′, and the amount discharged to the inverter device A ′ for the storage battery system is increased (or the amount to be charged is decreased). In addition, the monitoring device C monitors the state of each inverter device A ′ and changes the adjustment amount of each inverter device A ′ according to the situation. For example, when a certain storage battery system is approaching the allowable charge amount, the amount charged to the storage battery system is not increased so much, the amount charged to other storage battery systems is further increased, or the load consumption is further increased. Let For example, Non-Patent Document 1 describes a system for controlling a load frequency by controlling power consumption in a heat pump water heater and charging in an electric vehicle by a central power supply command station.

Masuda, Shimizu, Yokoyama, "Load frequency control using a large number of heat pump water heaters and electric vehicles in an electric power system with a large amount of renewable energy power supply", IEEJ Transactions B (Power and Energy Division) Vol .132 No.1 pp.23-33 Reza Olfati-Saber, J. Alex Fax, and Richard M. Murray, "Consensus and Cooperation in Networked Multi-Agent Systems", Proceedings of the IEEE, Vol. 95, No. 1, (2007) Mehran Mesbahi and Magnus Egerstedt, "Graph Theoretic Methods in Multiagent Networks", Princeton (2010)

  However, when the monitoring device C controls the active power of each inverter device A ', there is a problem that the system becomes large, it is difficult to flexibly cope with the increase / decrease of the inverter device A', and it is vulnerable to failure. That is, it is necessary to provide the monitoring device C and communicate with each inverter device A ′. In the case of wired communication, it is necessary to connect the monitoring device C and each inverter device A 'via a communication line. In the case of wireless communication, it is necessary to prevent radio waves from being blocked by obstacles. Further, when increasing or decreasing the inverter device A ′, it is necessary to change the control program of the monitoring device C. Furthermore, when the monitoring device C fails, there is also a problem that control cannot be performed. A similar problem occurs even when one inverter device A ′ (master) having the function of the monitoring device C controls another inverter device A ′ (slave).

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a method capable of solving the above-described problems and adjusting the output active power of each inverter device. .

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

  The control circuit provided by the first aspect of the present invention is a control circuit that controls an inverter circuit included in each inverter device in a power system in which a plurality of inverter devices that are not in a master-slave relationship are connected in parallel, Active power control means for generating an active power compensation value for controlling the active power output or input by the inverter device, system frequency detection means for detecting the system frequency, and compensation for controlling the system frequency to a target value System frequency control means for generating a value, cooperative correction value generation means for generating a correction value for cooperation with each inverter device, and addition means for adding the correction value to the compensation value to calculate a correction compensation value PWM signal generation means for generating a PWM signal based on the active power compensation value plus the correction compensation value; and the correction compensation Weighting means for weighting and communication means for communicating with at least one other inverter device, wherein the communication means transmits a weighted correction compensation value to the other inverter device, and the cooperative correction The value generation means generates the correction value using a calculation result based on the weighted correction compensation value and the reception compensation value received by the communication means from the other inverter device. Note that “not in the master-slave relationship” means that one of the inverter devices (master: master) does not monitor or control the other (slave: slave), but all have equal relationships. Means. In addition, the “power system” means, for example, a power system in which a plurality of inverter devices are connected in parallel, but a power plant (for example, a mega solar) in which a large number of inverter devices are connected in parallel to perform solar power generation, This includes power plants that produce wind power (wind farms).

  In a preferred embodiment of the present invention, the cooperative correction value generation means includes a calculation means for performing a calculation based on the weighted correction compensation value and the reception compensation value, and a calculation result output by the calculation means. Integrating means for integrating to calculate the correction value.

  In a preferred embodiment of the present invention, the calculation means calculates the calculation result by subtracting the weighted correction compensation value from the reception compensation value and adding all the subtraction results.

  In a preferred embodiment of the present invention, the calculating means subtracts the weighted correction compensation values from the reception compensation values, adds all the subtraction results, and the communication means performs communication. The operation result is calculated by dividing by the number of inverter devices.

  In a preferred embodiment of the present invention, the computing means subtracts the weighted correction compensation value from the reception compensation value, adds all the subtraction results, and multiplies the weighted correction compensation value. Thus, the calculation result is calculated.

  In a preferred embodiment of the present invention, the calculation means subtracts the reception compensation value from the weighted correction compensation value, adds all the subtraction results, and squares the weighted correction compensation value. The result of the operation is calculated by multiplying.

  In a preferred embodiment of the present invention, the weighting means performs weighting by dividing the correction compensation value by a preset weighting value.

  In a preferred embodiment of the present invention, the apparatus further comprises temperature detecting means for detecting the temperature of the inverter circuit, and weighting value setting means for setting a weighting value corresponding to the temperature, wherein the weighting means includes the weighting value. Weighting is performed by dividing the correction compensation value by the weighting value set by the setting means.

  In a preferred embodiment of the present invention, the clock means for outputting the date or time, and the weight value are stored in association with the date or time, and the date or time corresponding to the date or time output by the clock means is stored. Weighting value setting means for setting a weighting value, and the weighting means performs weighting by dividing the correction compensation value by the weighting value set by the weighting value setting means.

  In a preferred embodiment of the present invention, the weighting unit further includes an active power calculating unit that calculates an output active power of the inverter circuit, and a weighting value setting unit that sets a weighting value corresponding to the output active power. Performs weighting by dividing the correction compensation value by the weighting value set by the weighting value setting means.

  In a preferred embodiment of the present invention, the active power control means limits the power input to the inverter device to a state less than a maximum state.

  In a preferred embodiment of the present invention, the communication means switches communication partners based on the system frequency detected by the system frequency detection means.

  The inverter device provided by the second aspect of the present invention includes the control circuit provided by the first aspect of the present invention and an inverter circuit.

  The power system provided by the third aspect of the present invention is characterized in that a plurality of inverter devices provided by the second aspect of the present invention are connected in parallel.

  A control method provided by a fourth aspect of the present invention is a control method for controlling an inverter circuit included in each inverter device in a power system in which a plurality of inverter devices that are not in a master-slave relationship are connected in parallel. A first step of generating an active power compensation value for controlling the active power output or input by the apparatus; and a first step of generating a compensation value for controlling the system frequency detected by the system frequency detecting means to a target value. 2, a third step of generating a correction value for cooperating with each inverter device, a fourth step of calculating a correction compensation value by adding the correction value to the compensation value, and the effective A fifth step of generating a PWM signal based on the power compensation value plus the correction compensation value; a sixth step of weighting the correction compensation value; and a weighted compensation Each inverter device performs a seventh step of transmitting a compensation value to at least one other inverter device and an eighth step of receiving a value transmitted by the other inverter device as a reception compensation value. In the third step, the correction value is generated using a calculation result based on the weighted correction compensation value and the reception compensation value received in the eighth step. .

  According to the present invention, the cooperative correction value generation means generates a correction value using a calculation result based on the weighted correction compensation value and the reception compensation value. When the cooperative correction value generating means of each inverter device performs this, the weighted correction compensation values of all the inverter devices converge to the same value. Therefore, the correction compensation value of each inverter device is a value corresponding to each weight. Since the adjustment amount of the output active power of each inverter device is adjusted based on the correction compensation value, the adjustment amount of the output active power can be adjusted according to the weighting. Each inverter device only needs to perform mutual communication with at least one inverter device (for example, a device located in the vicinity or a device with which communication has been established). There is no need to communicate with the inverter device. Therefore, the system does not become a big deal. Even when a certain inverter device breaks down, it is only necessary that all other inverter devices can communicate with any one of the inverter devices. Moreover, it can respond flexibly to the increase / decrease of the inverter device.

  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 inverter apparatus which concerns on 1st Embodiment. It is a figure which shows the electric power system which concerns on 1st Embodiment. It is a figure for demonstrating the system frequency control system of an inverter apparatus. It is a figure for demonstrating the system frequency control system of the whole electric power system. 3 is a graph representing the power system shown in FIG. It is a figure showing the control system of the system frequency of the whole electric power system concerning a 1st embodiment. It is a figure for demonstrating the internal structure of a current control part. It is a figure which shows the simulation result which confirmed the fluctuation | variation suppression of the system frequency in an electric power system. It is a figure which shows the simulation result which confirmed the fluctuation | variation suppression of the system frequency in an electric power system. It is a figure which shows the simulation result which confirmed the fluctuation | variation suppression of the system frequency in an electric power system. It is a figure for demonstrating the inverter apparatus which concerns on 2nd Embodiment. It is a figure for demonstrating the inverter apparatus which concerns on 3rd Embodiment. It is a figure for demonstrating the inverter apparatus which concerns on 4th Embodiment. It is a figure which shows the conventional electric power system.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings, taking as an example a case where a control circuit according to the present invention is used in an inverter device linked to a power system.

  FIG. 1 is a diagram for explaining the inverter device according to the first embodiment. FIG. 2 is a diagram illustrating a power system in which a plurality of inverter devices according to the first embodiment are connected to a power system.

  The inverter device A is a so-called power conditioner. As shown in FIG. 1, the inverter device A includes an inverter circuit 2, a control circuit 3, a current sensor 4, a voltage sensor 5, and a DC voltage sensor 6, and is linked to the power system B. The inverter device A converts the DC power output from the DC power source 1 into AC power by the inverter circuit 2 and outputs the AC power to the power system B. Although not shown, a transformer for boosting (or stepping down) the AC voltage is provided on the output side of the inverter circuit 2.

  Further, as shown in FIG. 2, another inverter device A is also linked to the power system B to which the inverter device A is linked. In FIG. 2, an electric power system in which five inverter devices A (A1 to A5) are linked to the electric power system B is illustrated. In the actual power system, more inverter devices A are connected, but for the sake of simplicity of explanation, extremely few cases are shown.

  The arrows shown in FIG. 2 indicate that communication is being performed. That is, the inverter device A1 performs mutual communication only with the inverter device A2, and the inverter device A2 performs mutual communication only with the inverter device A1 and the inverter device A3. The inverter device A3 communicates only with the inverter device A2 and the inverter device A4, the inverter device A4 communicates only with the inverter device A3 and the inverter device A5, and the inverter device A5 communicates with the inverter device A4. Only doing mutual communication.

  Returning to FIG. 1, the DC power source 1 outputs DC power and includes a solar cell. A solar cell generates direct-current power by converting solar energy into electrical energy. The DC power source 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 from a solar cell. For example, the DC power source 1 may be a fuel cell, a storage battery, an electric double layer capacitor, a lithium ion battery, or AC power generated by a diesel engine generator, a micro gas turbine generator, a wind turbine generator, or the like. It may be a device that converts to DC power and outputs it.

  The inverter circuit 2 converts DC power input from the DC power source 1 into AC power and outputs the AC power. The inverter circuit 2 includes a PWM control inverter and a filter (not shown). The PWM control inverter is a three-phase inverter provided with three sets of six switching elements (not shown). Based on the PWM signal input from the control circuit 3, each switching element is switched on and off to generate DC power. Convert to AC power. The filter removes high frequency components due to switching. The inverter circuit 2 is not limited to this. For example, the PWM control inverter may be a single-phase inverter or a multi-level inverter. Further, the present invention is not limited to PWM control, and other methods such as phase shift control may be used.

  The current sensor 4 detects an instantaneous value of the three-phase output current of the inverter circuit 2. The current sensor 4 digitally converts the detected instantaneous value and outputs it to the control circuit 3 as current signals Iu, Iv, Iw (the three current signals may be collectively described as “current signal I”). . The voltage sensor 5 detects an instantaneous value of the three-phase interconnection point voltage of the inverter device A. The voltage sensor 5 digitally converts the detected instantaneous value and outputs it to the control circuit 3 as voltage signals Vu, Vv, and Vw (the three voltage signals may be collectively described as “voltage signal V”). . The DC voltage sensor 6 detects the input voltage of the inverter circuit 2. The DC voltage sensor 6 digitally converts the detected voltage and outputs it to the control circuit 3 as a voltage signal Vdc.

  The control circuit 3 controls the inverter circuit 2 and is realized by, for example, a microcomputer. The control circuit 3 according to the present embodiment controls the input voltage, output reactive power, output current, and system frequency of the inverter circuit 2. Among these, about the system frequency, all the inverter apparatuses A (A1-A5) (refer FIG. 2) linked to the electric power grid | system B perform control in cooperation.

  A system frequency control system according to the present invention will be described below with reference to FIGS.

  FIG. 3 is a diagram for explaining a system frequency control system of the inverter device A.

FIG. 3A shows a model of a general inverter device. The active power output from the inverter device is P, the reactive power is Q, the d-axis component and the q-axis component of the output current of the inverter device are Id and Iq (respective target values are Id ^* and Iq ^* ). The d-axis component and the q-axis component are two-phase components of the rotating coordinate system after being converted by a three-phase / two-phase converting process and a rotating coordinate converting process described later. Assuming that the internal phase of the inverter device completely follows the phase of the interconnection point voltage, the q-axis component of the output voltage is Vq = 0, and the d-axis component is Vd = V (the interconnection point voltage). Effective value)
P = Vd · Id + Vq · Iq = V · Id
Q = Vd · Iq−Vq · Id = V · Iq
It has become.

In the present invention, since fluctuations in the system frequency are suppressed by adjusting the output active power, a control system for suppressing system frequency fluctuations is added to the model of FIG. FIG. 3B shows a model in which a control system for suppressing system frequency fluctuation is added. In FIG. 3B, a system frequency control system that outputs a system frequency compensation value ΔId ^* when a deviation Δω from the target value of the angular frequency ω of the power system is input is added, and a system frequency compensation value ΔId ^* is output. It is added to the target value Id ^* of the d-axis component of the current. In the control of the power system, an angular frequency (a frequency obtained by multiplying the frequency by 2π) is generally used rather than a frequency. Therefore, the angular frequency is also used in this specification.

The dynamics of the current control system, the PWM and the inverter main circuit can be ignored because they are faster than the dynamics of the power control system. FIG. 3C shows a model approximated by ignoring these. Note that Id ′ ^* = Id ^* + ΔId ^* .

  FIG. 3D shows a model in which attention is paid only to the system frequency control system in the model of FIG.

FIG. 4 is a diagram for explaining a system frequency control system of the entire power system. The active power output from each inverter device A1 to A5 is changed by ΔP ₁ to ΔP ₅ , respectively, and the active power supplied to the power system is changed by a change amount ΔP obtained by adding these. The angular frequency ω of the power system fluctuates due to fluctuations in the supplied active power P. As the frequency variation model, the equivalent generator model described in Non-Patent Document 1 is used. This equivalent generator model is formulated as the following equation (1) on the assumption that all generators in the system are performing complete synchronous operation. Here, the equivalent inertia constant M is updated in accordance with the inertia constant of the generators in parallel. The damping D is updated according to the load size. Further, the fluctuation (disturbance) ΔPw of the active power includes a fluctuation due to a load fluctuation or a change in the output of the solar cell. FIG. 4 shows a system that suppresses fluctuations in the system frequency (system angular frequency) by adjusting the active power of each inverter device A.

  However, in this case, since each inverter device A does not adjust the output active power in cooperation, the output active power adjusted by each inverter device A is the gain, location, DC power supply set internally 1 and so on. For example, it is impossible to adjust the output active power of the inverter device A1 by half that of the other devices and to adjust the inverter devices A2 to A5 evenly or according to the capacity of each inverter device A.

  Next, a method for adjusting the output active power in cooperation with each inverter device A will be described.

  There is known a consensus algorithm for converging a plurality of control target state values to the same value (see Non-Patent Documents 2 and 3). When each control target is a vertex and the communication state between each control target is expressed as a graph, if the graph is connected by an undirected graph in the graph theory, the state of each control target is determined using a consensus algorithm. The values can converge to the same value to achieve consensus. For example, when the communication state of the power system shown in FIG. 2 is expressed in a graph, it is as shown in FIG. The vertices A1 to A5 represent the inverter devices A1 to A5, respectively, and the sides with arrows represent the communication states between the inverter devices. Each side indicates that mutual communication is performed, and the graph is an undirected graph. Since a communication path exists for any two vertices of the graph, the graph is connected. Therefore, in the case of the power system shown in FIG. 2, consensus can be achieved. In addition, since the graphs shown in FIGS. 5B and 5C are also connected by undirected graphs, the communication states of the inverter devices A1 to A5 in the power system of FIG. Consensus can be achieved. In this way, the inverter device A performs mutual communication with at least one inverter device A among the inverter devices A connected to the power system, and any two inverter devices A connected to the power system. As long as a communication path exists (hereinafter, this state is referred to as a “connected state”), it is necessary to communicate with all inverter devices A connected to the power system. Absent.

In the present embodiment, the value of the state of each control target is not converged to the same value, but weighting is performed to converge the weighted value to the same value. That is, the weighting value W _i of each inverter device A is set in advance, weighting is performed by dividing the state value by the weighting value W _i , and the weighted value is converged to the same value. Thus, the value of each state converges to a value corresponding to the weighting value W _i. For example, if W ₁ = W ₂ = W ₃ = W ₄ = 1 and W ₅ = 10, the value of the state of the inverter device A5 converges to 10 times the value of the state of the inverter devices A1 to A4. .

  FIG. 6 is obtained by adding a consensus algorithm and weighting to the system shown in FIG. 4, and represents a control system that suppresses fluctuations in the system frequency by each inverter device A coordinating to adjust the active power. .

The compensation value ΔId _i ′ (= ΔId _i ^* / W _i ) obtained by dividing the compensation value ΔId _i ^* by the weighting value W _i converges to the same value by the consensus algorithm. 'When, the inverter device A _i, the compensation value ^{_{ΔId i * = W i · ΔIdα}} ' the convergence value Derutaaidiarufa will adjust the effective power according to. That is, by adjusting the effective power corresponding to the weighting value W _i. Therefore, for example, if W ₁ = W ₂ = W ₃ = W ₄ = 1 and W ₅ = 10, the inverter device A5 can adjust the active power 10 times that of the inverter devices A1 to A4.

  Returning to FIG. 1, the control circuit 3 performs PWM based on the current signal I input from the current sensor 4, the voltage signal V input from the voltage sensor 5, and the voltage signal Vdc input from the DC voltage sensor 6. A signal is generated and output to the inverter circuit 2. The control circuit 3 includes a reactive power control unit 30, an input voltage control unit 31, a system frequency control unit 32, a cooperative correction value generation unit 33, an adder 34, a current control unit 35, a command signal generation unit 36, and a PWM signal generation unit 37. A weighting unit 38, a communication unit 39, and a system frequency detection unit 40.

The reactive power control unit 30 is for controlling the output reactive power of the inverter circuit 2. Although not shown, the reactive power control unit 30 calculates the output reactive power of the inverter circuit 2 from the instantaneous value of the current detected by the current sensor 4 and the instantaneous value of the voltage detected by the voltage sensor 5, and the target value The PI control (proportional integral control) is performed on the deviation from, and the reactive power compensation value is output. The reactive power compensation value is input to the current control unit 35 as the target value Iq ^* . The control of the reactive power control unit 30 is not limited to PI control, and other control such as I control (integration control) may be performed.

The input voltage control unit 31 is for controlling the input voltage of the inverter circuit 2. The input voltage control unit 31 controls the input power by controlling the input voltage, thereby controlling the output active power of the inverter circuit 2. The input voltage control unit 31 receives a deviation ΔVdc between the voltage signal Vdc input from the DC voltage sensor 6 and the input voltage target value Vdc ^* that is a target value thereof, performs PI control, and outputs an active power compensation value. . The control of the input voltage control unit 31 is not limited to PI control, and other control such as I control may be performed.

  The system frequency detector 40 detects the angular frequency ω of the power system B. The system frequency detector 40 receives the voltage signal V from the voltage sensor 5, detects the angular frequency of the interconnection point voltage, and outputs this as the angular frequency ω of the power system B. As a method for detecting the angular frequency, a generally used method such as a PLL method or a zero-cross point counting method may be used.

The system frequency control unit 32 is for controlling the system frequency. The system frequency control unit 32 controls the system frequency by adjusting the active power output from the inverter circuit 2. The system frequency control unit 32 receives the deviation Δω between the angular frequency ω output from the system frequency detection unit 40 and the system frequency target value ω ^{* that} is the target value, performs PI control, and outputs the system frequency compensation value To do. The system frequency compensation value is input to the adder 34. The control of the system frequency control unit 32 is not limited to PI control, and other control such as I control may be performed. Further, the system frequency detection unit 40 detects the system frequency f, and the system frequency control unit 32 receives the deviation Δf between the system frequency f and its target value f ^*, and outputs the system frequency compensation value. Also good.

  The cooperation correction value generation unit 33 generates a cooperation correction value for cooperation with each inverter device A. Details of the cooperative correction value generation unit 33 will be described later.

The adder 34 adds the cooperative correction value input from the cooperative correction value generation unit 33 to the system frequency compensation value input from the system frequency control unit 32 to calculate a correction compensation value ΔId _i ^* . The active power compensation value output from the input voltage control unit 31 is added to the correction compensation value ΔId _i ^* output from the adder 34 and input to the current control unit 35 as the target value Id ^* . The adder 34 also outputs the calculated correction compensation value ΔId _i ^* to the weighting unit 38.

  The current control unit 35 is for controlling the output current of the inverter circuit 2. The current control unit 35 generates a current compensation value based on the current signal I input from the current sensor 4 and outputs the current compensation value to the command signal generation unit 36.

  FIG. 7 is a functional block diagram for explaining the internal configuration of the current control unit 35.

  The current control unit 35 includes a three-phase / two-phase conversion unit 351, a rotation coordinate conversion unit 352, an LPF 353, an LPF 354, a PI control unit 355, a PI control unit 356, a stationary coordinate conversion unit 357, and a two-phase / three-phase conversion unit. 358.

  The three-phase / two-phase conversion unit 351 performs a so-called three-phase / two-phase conversion process (αβ conversion process). The three-phase / two-phase conversion process is a process that converts a three-phase AC signal into an equivalent two-phase AC signal. The three-phase AC signal is a stationary orthogonal coordinate system (hereinafter referred to as “static coordinate system”). In this case, the signals are decomposed into orthogonal α-axis and β-axis components and the components of the respective axes are added to each other, thereby converting into an AC signal of the α-axis component and an AC signal of the β-axis component. The three-phase / two-phase converter 351 converts the three-phase current signals Iu, Iv, and Iw input from the current sensor 4 into an α-axis current signal Iα and a β-axis current signal Iβ, and a rotational coordinate converter 352. Output to.

The conversion process performed by the three-phase / two-phase conversion unit 351 is represented by a determinant represented by the following equation (2).

  The rotation coordinate conversion unit 352 performs a so-called rotation coordinate conversion process (dq conversion process). The rotation coordinate conversion process is a process of converting a two-phase signal in the stationary coordinate system into a two-phase signal in the rotation coordinate system. The rotating coordinate system is an orthogonal coordinate system having orthogonal d-axis and q-axis and rotating in the same rotational direction at the same angular velocity as the fundamental wave of the interconnection point voltage. The rotating coordinate conversion unit 352 converts the α-axis current signal Iα and β-axis current signal Iβ of the stationary coordinate system input from the three-phase / two-phase conversion unit 351 based on the phase θ of the fundamental wave of the interconnection point voltage. It is converted into a d-axis current signal Id and a q-axis current signal Iq in the rotating coordinate system and output.

The conversion process performed by the rotation coordinate conversion unit 352 is expressed by a determinant represented by the following expression (3).

  LPF 353 and LPF 354 are low-pass filters and pass only the DC components of d-axis current signal Id and q-axis current signal Iq, respectively. Through the rotation coordinate conversion process, the fundamental wave components of the α-axis current signal Iα and the β-axis current signal Iβ are converted into DC components of the d-axis current signal Id and the q-axis current signal Iq, respectively. That is, the LPF 353 and the LPF 354 remove unbalanced components and harmonic components and pass only the fundamental wave components.

The PI control unit 355 performs PI control based on the deviation between the DC component of the d-axis current signal Id and the target value, and outputs a current compensation value Xd. The correction compensation value ΔId _i ^* is added to the active power compensation value output from the input voltage control unit 31 and used as the target value Id ^* of the d-axis current signal Id. The PI control unit 356 performs PI control based on the deviation between the DC component of the q-axis current signal Iq and the target value Iq ^*, and outputs a current compensation value Xq. The reactive power compensation value output from reactive power control unit 30 is used as target value Iq ^* of q-axis current signal Iq.

  The stationary coordinate conversion unit 357 converts the current compensation values Xd and Xq respectively input from the PI control unit 355 and the PI control unit 356 into the current compensation values Xα and Xβ of the stationary coordinate system. In contrast to 352, the conversion processing is performed. The static coordinate conversion unit 357 performs a so-called static coordinate conversion process (inverse dq conversion process), and calculates the current compensation values Xd and Xq of the rotating coordinate system based on the phase θ and the current compensation value Xα of the static coordinate system. , Xβ.

The conversion process performed by the stationary coordinate conversion unit 357 is represented by a determinant represented by the following expression (4).

  The two-phase / three-phase conversion unit 358 converts the current compensation values Xα and Xβ input from the stationary coordinate conversion unit 357 into three-phase current compensation values Xu, Xv, and Xw. The two-phase / three-phase conversion unit 358 performs a so-called two-phase / three-phase conversion process (reverse αβ conversion process), and performs a conversion process opposite to the three-phase / two-phase conversion unit 351.

The conversion process performed by the two-phase / three-phase conversion unit 358 is represented by a determinant represented by the following equation (5).

  In addition, although this embodiment demonstrated the case where the inverter apparatus A was a three-phase system, a single phase system may be sufficient. In the case of a single-phase system, the current control unit 35 may control the single-phase current signal that detects the output current of the inverter circuit 2.

  The command signal generator 36 generates a command signal based on the current compensation values Xu, Xv, Xw input from the current controller 35 and outputs the command signal to the PWM signal generator 37.

  The PWM signal generation unit 37 generates a PWM signal. The PWM signal generation unit 37 generates a PWM signal by a triangular wave comparison method based on the carrier signal and the command signal input from the command signal generation unit 36. For example, a pulse signal that is high when the command signal is larger than the carrier signal and low when the command signal is equal to or less than the carrier signal is generated as a PWM signal. The generated PWM signal is output to the inverter circuit 2. The PWM signal generation unit 37 is not limited to the case where the PWM signal is generated by the triangular wave comparison method. For example, the PWM signal generation unit 37 may generate the PWM signal by a hysteresis method.

The weighting unit 38 weights the correction compensation value ΔId _i ^* input from the adder 34. A weighting value W _i is set in the weighting unit 38 in advance. The weighting unit 38 outputs the weighted correction compensation value ΔId _i ′ obtained by dividing the correction compensation value ΔId _i ^* by the weighting value W _i to the communication unit 39 and the cooperative correction value generation unit 33.

The weighting value _Wi is set in advance according to the magnitude (adjustment amount) of the output active power to be adjusted by the inverter device A. For example, since the capacity of the inverter device A1 (see FIG. 2) is larger than the capacity of the inverter devices A2 to A5, when the adjustment amount of the inverter device A1 is to be increased (when the adjustment amount of the inverter devices A2 to A5 is to be made as small as possible). , the weighting value W ₁ of the inverter device A1, set the larger value as compared with the weighting value W ₂ to _W-5 of the other inverter A2 to A5. The weighting values W _{2 to} W ₅ may be the same value in order to make the adjustment amounts equal. The method of setting the weighting value W _i is not limited, for example, may be set according to the size of the solar cell panel is connected to the inverter A.

The communication unit 39 communicates with the control circuit 3 of the other inverter device A. The communication unit 39 receives the weighted correction compensation value ΔId _i ′ from the weighting unit 38 and transmits it to the communication unit 39 of another inverter device A. Further, the communication unit 39 outputs the compensation value ΔId _j ′ received from the communication unit 39 of the other inverter device A to the cooperative correction value generation unit 33. Note that the communication method is not limited, and may be wired communication or wireless communication.

For example, when the inverter device A is the inverter device A2 shown in FIG. 2, the communication unit 39 transmits the weighted correction compensation value ΔId ₂ ′ to the communication units 39 of the inverter devices A1 and A3, and the communication unit of the inverter device A1. 39 receives the compensation value ΔId ₁ ′, and receives the compensation value ΔId ₃ ′ from the communication unit 39 of the inverter device A3.

  Next, details of the cooperative correction value generation unit 33 will be described.

The cooperative correction value generation unit 33 receives the weighted correction compensation value ΔId _i ′ (hereinafter abbreviated as “compensation value ΔId _i ′”) input from the weighting unit 38 and the communication unit 39. Using the compensation value ΔId _j ′ of the other inverter device A, a cooperative correction value for cooperating with each inverter device A is generated. Even if the compensation value ΔId _i ′ and the compensation value ΔId _j ′ are different, the calculation value in the cooperative correction value generation unit 33 is repeated so that the compensation value ΔId _i ′ and the compensation value ΔId _j ′ are a common value. Converge to. As shown in FIG. 1, the cooperative correction value generation unit 33 includes a calculation unit 331, a multiplier 332, and an integrator 333.

The computing unit 331 performs computation based on the following equation (6). That is, the calculation unit 331 subtracts the compensation value ΔId _i ′ input from the weighting unit 38 from each compensation value ΔId _j ′ input from the communication unit 39, and adds the calculation result u _i obtained by adding all the subtraction results. The result is output to the multiplier 332.

For example, if the inverter apparatus A of the inverter device A2 (see FIG. 2), computation unit 331 performs calculation of the following equation (7), and outputs the operation result u _2.

The multiplier 332 multiplies the calculation result u _i input from the calculation unit 331 by a predetermined coefficient ε and outputs the result to the integrator 333. 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 inverter devices A connected to the power system among d _i that is the number of other inverter devices A with which the communication unit 39 communicates. That is, it is the number of compensation values ΔId _j ′ input to the communication unit 39 of the inverter device A connected to the power system that communicates with the largest number of other inverter devices A. Incidentally, the coefficient epsilon, operation result u _i becomes too large (small), in order to suppress the fluctuation of the cooperative correction value becomes too large, it is intended to be multiplied to the calculation result u _i. Therefore, when the process in the cooperative correction value generation unit 33 is a continuous time process, it is not necessary to provide the multiplier 332.

  The integrator 333 generates and outputs a cooperative correction value by integrating the value input from the multiplier 332. The integrator 333 generates a cooperative correction value by adding the value input from the multiplier 332 to the previously generated cooperative correction value. The cooperative correction value is output to the adder 34.

  In the present embodiment, the case where the control circuit 3 is realized as a digital circuit has been described, but it may be realized as an analog circuit. Further, the processing performed by each unit may be designed by a program, and the computer may function as the control circuit 3 by executing the program. The program may be recorded on a recording medium and read by a computer.

In the present embodiment, the cooperative correction value generation unit 33 uses the compensation value ΔId _i ′ input from the weighting unit 38 and the compensation value ΔId _j ′ of the other inverter device A input from the communication unit 39. Then, a cooperative correction value is generated. When the compensation value ΔId _i ′ is larger than the arithmetic mean value of the respective compensation values ΔId _j ′, the computation result u _i output from the computation unit 331 becomes a negative value. Then, the cooperative correction value becomes small, and the compensation value ΔId _i ′ also becomes small. On the other hand, when the compensation value ΔId _i ′ is smaller than the arithmetic mean value of the respective compensation values ΔId _j ′, the computation result u _i output from the computation unit 331 becomes a positive value. As a result, the cooperative correction value increases and the compensation value ΔId _i ′ also increases. That is, the compensation value ΔId _i ′ approaches the arithmetic mean value of each compensation value ΔId _j ′. By performing this process in each inverter device A, the compensation value ΔId _i ′ of each inverter device A converges to the same value. It has been mathematically proved that the value of the state to be controlled converges to the same value by using the consensus algorithm (see Non-Patent Documents 1 and 2). In the case of the present embodiment, the compensation value ΔId _i ′ is the value of the state to be controlled.

  Hereinafter, in the power system shown in FIG. 2, a description will be given of a simulation in which each inverter device A confirms that the fluctuation of the system frequency is suppressed by adjusting the output active power in cooperation. A simulation was performed using the control system shown in FIG.

The proportional gain Kp ₁ of the system frequency control unit 32 of the inverter device A1 is “1”, the integral gain Ki ₁ is “2”, the proportional gain Kp ₂ of the system frequency control unit 32 of the inverter device A2 is “1”, and the integral gain Ki. ₂ is “0.5”, the proportional gain Kp ₃ of the system frequency control unit 32 of the inverter device A3 is “2”, the integral gain Ki ₃ is “3”, and the proportional gain Kp ₄ of the system frequency control unit 32 of the inverter device A4. Is “5”, the integral gain Ki ₄ is “1”, the proportional gain Kp ₅ of the system frequency control unit 32 of the inverter A5 is “0.5”, the integral gain Ki ₅ is “0.3”, and the interconnection point The voltages V _{1 to} V ₅ are “1 [pu]”, M is “9 [s]”, and D is “2 [pu]]. 8 to 10 show the results of the simulation.

8 and FIG. 9 are weighting values W _{1 to} W ₅ set in the weighting unit 38 of the inverter devices A1 to A5, where W ₁ = W ₂ = W ₃ = W ₄ = W ₅ = 1. Yes, to confirm that each inverter device A adjusts the output active power in cooperation. FIG. 8 is for comparison, and shows the case without cooperation (that is, when the control system shown in FIG. 4 is used), and FIG. 9 shows the case with cooperation (that is, shown in FIG. 6). (When using a control system).

  In both cases, the disturbance ΔPw is 0.5 [p. u. ] Was step-injected. FIG. 8A and FIG. 9A show changes over time in the deviation Δω of the system angular frequency. Moreover, FIG.8 (b) and FIG.9 (b) have shown the time change of the adjustment amount of the output active power of each inverter apparatus A1-A5. In this simulation, a disturbance ΔPw that increases the active power is injected and each inverter device A1 to A5 is adjusted so as to suppress the output active power. In each figure (b), since the case where output active electric power is increased is made positive, the adjustment amount (suppression amount) is shown by the negative value.

  In the case of FIG. 8, fluctuations in the system angular frequency can be immediately suppressed, but the adjustment amount of each inverter device A1 to A5 is fixed to a value corresponding to each gain. Therefore, the adjustment amount of each inverter device A1 to A5 cannot be controlled. In the case of FIG.8 (b), the output active power of inverter apparatus A3 is suppressed most, and this adjustment amount cannot be made small.

  In the case of FIG. 9 as well, as in the case of FIG. 8, the fluctuation of the system angular frequency can be immediately suppressed. In the case of FIG. 9, the adjustment amounts of the inverter devices A1 to A5 converge to the same value in about 24 seconds from the start of the simulation. That is, each inverter apparatus A1-A5 is adjusting the output active power in cooperation.

  A simulation was also performed for each of the cases where the communication state of the power system of FIG. 2 is the graphs shown in FIGS. 5B and 5C. In these cases as well as in the case of FIG. 9, it was possible to immediately suppress the fluctuation of the system angular frequency, and it was confirmed that the adjustment amounts of the inverter devices A1 to A5 converge to the same value. Further, in the case of the graph of FIG. 5B, the time until convergence is shorter than in the case of FIG. 9 (in the case of the graph of FIG. 5A), and in the case of the graph of FIG. The time to convergence has become even shorter. The simulation results are not shown.

In FIG. 10, the weighting values W _{1 to} W ₅ set in the weighting unit 38 of the inverter devices A1 to A5 are set to W ₂ = W ₃ = W ₄ = W ₅ = 1, and W ₁ is changed with time. It is for confirming that the adjustment amount of the output active power of each inverter apparatus A changes with a weighting value. Also in the case of FIG. 10, 10 seconds after the simulation starts, the disturbance ΔPw is 0.5 [p. u. ] Was step-injected. FIG. 10A shows a time change of the system angular frequency deviation Δω, and FIG. 10B shows a time change of the adjustment amount of the output active power of each of the inverter devices A1 to A5. The weighting value W ₁ is set to “1” at the start of the simulation, but is changed to “2” 30 seconds after the start of the simulation, changed to “4” after 60 seconds, and changed to “8” after 90 seconds, 120 seconds Later, it is changed to “16”.

As shown in FIG. 10, the fluctuation of the system angular frequency can be immediately suppressed, and the adjustment amounts of the inverter devices A1 to A5 converge to the same value in about 24 seconds from the start of the simulation. Further, after changing the weighting value W ₁ to “2”, the adjustment amount of the inverter devices A2 to A5 is small (the value in FIG. 10B is large) and the adjustment amount of the inverter device A1 is large (FIG. 10 (b) is small). That is, the inverter device A1 comes to bear a part of the adjustment amount of the inverter devices A2 to A5. The adjustment amount of the inverter devices A2 to A5 is half of the adjustment amount of the inverter device A1. Further, after changing the weighting value W ₁ to “4”, the adjustment amount of the inverter devices A2 to A5 is ¼ of the adjustment amount of the inverter device A1. After the weight value W ₁ is changed to “8”, the adjustment amount of the inverter devices A2 to A5 becomes 1/8 of the adjustment amount of the inverter device A1, and the weight value W ₁ is changed to “16”. The adjustment amount of the inverter devices A2 to A5 is 1/16 of the adjustment amount of the inverter device A1. Thus, it was confirmed that the adjustment amount of the output active power of each inverter device A changes depending on the weighting value.

According to the present embodiment, the cooperative correction value generation unit 33 generates a cooperative correction value using a calculation result based on the compensation value ΔId _i ′ and the compensation value ΔId _j ′. When the cooperative correction value generation unit 33 of each inverter device A1 to A5 performs this, the compensation values ΔId _i ′ of all the inverter devices A1 to A5 converge to the same value. Therefore, the correction compensation values ΔId _i ^* of the inverter devices A1 to A5 are values corresponding to the respective weighting values W _{1 to} W ₅ . Since the adjustment amount of the output active power of each of the inverter devices A1 to A5 is adjusted based on the correction compensation value ΔId _i ^* , the adjustment amount of the output active power of each of the inverter devices A1 to A5 is set to the weight values W _{1 to} W _5. Can be adjusted according to.

  In addition, each inverter device A connected to the power system performs mutual communication only with at least one inverter device A (for example, a device that is located in the vicinity or that has established communication), and the power system It is only necessary that the connected state is established, and it is not necessary for one inverter device A or the monitoring device to communicate with all other inverter devices A. Therefore, the system does not become a big deal. Moreover, even when a certain inverter device A fails or when a certain inverter device A is reduced, all the other inverter devices A can communicate with any one of the inverter devices A, and the power system is in a connected state. Good. Further, when the number of inverter devices A is increased, it is only necessary that the inverter device A performs mutual communication with at least one inverter device A. Therefore, the increase / decrease in the inverter device A can be flexibly dealt with.

  In the first embodiment, the case where the inverter device A converts the input from the DC power source 1 and outputs it to the power system B has been described, but the present invention is not limited to this. For example, the inverter device A may be an inverter device for charging and discharging a storage battery system, or may be an inverter device for a load that can be adjusted in power. In these inverter devices A, the active power charged (or discharged) to the storage battery or the active power consumed by the load is adjusted. That is, the active power to be charged or consumed is increased when the system frequency is increased, and the active power to be charged or consumed is decreased when the system frequency is decreased. Even in these cases, the adjustment of the active power can be performed in cooperation with the other inverter device A. For solar power and wind power, etc., we do not want to adjust the output active power as much as possible. Therefore, the weighting value W of the inverter device A used in solar power generation or wind power generation is set to a small value, and the weighting value W of the inverter device A used in the storage battery system or the load is set to a large value. As a result, the active power to be charged (or discharged) to the storage battery or the active power to be consumed by the load is adjusted without adjusting the output active power by solar power generation or wind power generation. Variations can be suppressed. In the case of a storage battery system or a load inverter device, the output active power may be controlled instead of controlling the input voltage. Specifically, an output active power control unit is provided in place of the input voltage control unit 31, the output active power of the inverter circuit 2 is calculated, and PI control is performed on the deviation from the target value to obtain an active power compensation value. Is output.

  In the case of the inverter device A that converts the input from the DC power source 1 such as a solar cell and outputs it to the power system B as in the first embodiment, the output active power is suppressed when the system frequency increases. An adjustment is made so that the output active power is increased when the system frequency is lowered. Therefore, in order to leave room for increasing the output active power, control is not performed so as to output the maximum power by MPPT control (maximum power point tracking control), but the output is controlled to a maximum of about 90%. There is a need.

  Alternatively, it is necessary to change the communication state when the system frequency decreases. That is, the communication network except the inverter device A performing MPPT control is controlled from the communication network when the normal or system frequency is increased (that is, the storage device or the inverter device A for load and the maximum output of about 90%). It is necessary to switch to a communication network composed only of the inverter device A. The inverter device A configuring the communication network after switching performs adjustment so as to increase active power in cooperation with communication. Switching of the communication network is performed by each inverter device A by the communication unit 39 changing the communication partner based on the system angular frequency ω detected by the system frequency detection unit 40.

  For example, when switching from the communication network shown in the graph of FIG. 5A to a communication network (see FIG. 5D) excluding the inverter devices A1 and A4 performing MPPT control, the inverter device A1 is connected to the inverter device A2. And the inverter device A2 also blocks communication with the inverter device A1. Further, the inverter device A3 cuts off communication with the inverter device A4 and communicates with the inverter device A5 instead. Inverter device A4 cuts off communication with inverter devices A3 and A5. Inverter device A5 cuts off communication with inverter device A4 and communicates with inverter device A3 instead. Thereby, it switches to the communication network shown to the graph of FIG.5 (d), and inverter apparatus A2, A3, A5 adjusts so that active power may be increased in cooperation. Inverter devices A1 and A4 do not adjust to increase the active power. When the state in which the system frequency is lowered is eliminated, the communication unit 39 of each inverter device A switches the communication network to the communication network shown in the graph of FIG.

In the first embodiment, assuming that the interconnection point voltage V ₁ ~V ₅ of each inverter A1 to A5 (see FIG. 6) is the same, the case of setting the weighting value W ₁ to _W-5 Although described, when the interconnection point voltages V _{1 to} V ₅ are different, the setting method of the weight values W _{1 to} W ₅ is changed. That is, when the interconnection point voltages V _{1 to} V ₅ are different, the output active powers are different even if each inverter device A _{1 to A 5} outputs the same current. Therefore, in order to adjust the amount of output active power of each inverter apparatus A1~A5 the same weighting value W ₁ to _W-5 rather than the same value, the interconnection node voltage V ₁ ~V ₅ The value must be proportional to the inverse. For example, when V ₁ = V ₂ = V ₃ = V ₄ = 2V ₅ (that is, when V ₅ is half of V _{1 to} V ₄ ), W ₁ = W ₂ = W ₃ = W ₄ = 1, W _By setting ₅ = 2, the adjustment amount of the output active power can be made the same.

In the first embodiment, the case where the arithmetic expression set in the arithmetic unit 331 is the expression (6) has been described, but the present invention is not limited to this. Another equation for converging the compensation value ΔId _i ′ of the inverter devices A1 to A5 to the same value may be used.

For example, the compensation value ΔId _i ′ can be converged to the same value even when the arithmetic expression set in the arithmetic unit 331 is the following expression (8). d _i is the number of other inverter devices A with which the communication unit 39 communicates, that is, the number of compensation values ΔId _j ′ input to the communication unit 39.

Further, when the calculation formulas set in the calculation unit 331 are the following formulas (9) to (11), the compensation value ΔId _i ′ can be converged to the same value.

  In the said 1st Embodiment, although the case where the fixed value was preset as a weighting value of each inverter apparatus A was demonstrated, it is not restricted to this. The weighting value of each inverter device A may be changeable.

FIG. 11 is a diagram for explaining an inverter device A according to the second embodiment. In FIG. 11, only the control circuit 3 is shown, and the description of the control circuit 3 that is common to the control circuit 3 according to the first embodiment (see FIG. 1) is omitted. The inverter device A according to the second embodiment differs from the inverter device A according to the first embodiment in that the weighting value _Wi is changed according to the temperature of the inverter circuit 2. As shown in FIG. 11, the inverter device A according to the second embodiment further includes a temperature detection unit 41 and a weight value setting unit 42 in the control circuit 3.

Although not shown, a temperature sensor is attached to the heat sink of the inverter circuit 2. The temperature detection unit 41 detects the temperature detected by the temperature sensor, and outputs the detected temperature to the weight value setting unit 42. Weighting value setting unit 42 sets the weighting value W _i corresponding to the temperature input from the temperature detector 41 to the weighting section 38. When the temperature of the inverter circuit 2 is high, it is considered that the inverter circuit 2 is burdened, so it is difficult to further increase the output active power. Therefore, it is better to reduce the adjustment amount. In the present embodiment, compared to a threshold value that sets the temperature input from the temperature detection unit 41 in advance, the temperature is changed to a smaller value the weighting value W _i if the threshold is greater than. Incidentally, may be set a plurality of threshold values, the weighting value W _i may be stepwise changed. Alternatively, a calculation formula for linearly calculating the weighted value W _i from the temperature input from the temperature detection unit 41 may be set, and the calculation result of the calculation formula may be set.

According to the second embodiment, when an excessive load is applied to the inverter circuit 2 of the inverter device A and the temperature of the inverter circuit 2 becomes high, the weighting value _Wi is changed to a small value. Thereby, the adjustment amount of the output active power of the said inverter apparatus A becomes small, and the adjustment amount of the output active power of the other inverter apparatus A becomes large correspondingly. As a result, it is possible to prevent the output active power of the inverter device A from being greatly increased. Also in the second embodiment, the same effects as in the first embodiment can be obtained.

  When the inverter device A participates in the adjustment (suppression) of the active power only when the system frequency increases (that is, when the inverter device A does not participate in the adjustment (increase) of the active power when the system frequency decreases), On the contrary, the adjustment amount (suppression amount) may be increased when the detected temperature is high. That is, by increasing the suppression amount, the output active power may be reduced, the burden on the inverter device A may be reduced, and another inverter device A may bear the corresponding amount.

FIG. 12 is a diagram for explaining an inverter device A according to the third embodiment. FIG. 12A shows only the control circuit 3 of the inverter device A according to the third embodiment, and the common part of the control circuit 3 with the control circuit 3 according to the first embodiment (see FIG. 1). Is omitted. The inverter device A according to the third embodiment is different from the inverter device A according to the first embodiment in that the weighting value _Wi is changed according to the date and time. As illustrated in FIG. 12A, the inverter device A according to the third embodiment further includes a clock unit 43 and a weight value setting unit 42 ′ in the control circuit 3.

  The clock unit 43 outputs the date and time (hereinafter collectively referred to as “date and time”) to the weight value setting unit 42 ′.

Weighting value setting unit 42 'sets the weighting value W _i corresponding to the date and time input from the clock unit 43 to the weighting section 38. Since the position of the sun changes with time, the shadowed area such as a building changes with time. In addition, since the sun's orbit changes depending on the date (for example, the sun's orbit differs greatly between the summer solstice and the winter solstice), the shadowed area such as a building also changes depending on the date. When the solar cell panel connected to the inverter device A is shaded, the electric power generated by the solar cell panel is reduced. In this case, it is desirable to avoid further suppressing the output power of the inverter device A, and it is difficult to further increase the output power, so it is desirable to reduce the adjustment amount. In this embodiment, by investigating the solar panel shadows such advance, the weighting value W _i of the inverter device A shadow takes solar panel is connected, to switch to a smaller value in the shadow takes time ing. Further, the weighting value W _i is made smaller as the shadowed area becomes larger. Specifically, the weight value setting unit 42 ′ stores a table of weight values W _i shown in FIG. 12B in the memory, and sets the weight value W _i corresponding to the date and time input from the clock unit 43. Read and set. In FIG. 12B, since the shadow is applied to the solar cell panel from 9:00 to 12:00 in January, a smaller value than usual is set for this date and time. The weight value W _i may be changed only by time regardless of the date, or may be changed only by date regardless of the time.

According to the third embodiment, on the date and time when the solar cell panel connected to the inverter device A is shaded, the weighting value _Wi is changed to a small value, and the adjustment amount of the output active power becomes small. Thereby, when the electric power generated by the shadow becomes small, the adjustment amount can be made small. In the third embodiment, the same effects as in the first embodiment can be obtained.

FIG. 13 is a diagram for explaining an inverter device A according to the fourth embodiment. In FIG. 13, the description of the common part of the control circuit 3 with the control circuit 3 according to the first embodiment (see FIG. 1) is omitted. The inverter device A according to the fourth embodiment is different from the inverter device A according to the first embodiment in that the weighting value _Wi is changed according to the output active power of the inverter circuit 2. As shown in FIG. 13, the inverter device A according to the fourth embodiment further includes an active power calculation unit 44 and a weight value setting unit 42 ″ in the control circuit 3.

  The active power calculation unit 44 calculates the output active power P of the inverter circuit 2, and the current signals Iu, Iv, Iw input from the current sensor 4 and the voltage signals Vu, Vv input from the voltage sensor 5. , Vw, and the output active power P is calculated. The active power calculation unit 44 outputs the calculated output active power P to the weighting value setting unit 42 ″.

The weight value setting unit 42 ″ sets the weight value W _i corresponding to the output active power P input from the active power calculation unit 44 in the weighting unit 38. When the output active power P is large, the capacity of the inverter device A is set. Since there is no room for this, it is difficult to increase the output active power even further, and therefore, in this embodiment, the adjustment amount is reduced. It is compared with the threshold value that the output effective power P input from the section 44 is set in advance, the output effective power P is changed to a smaller value the weighting value W _i if the threshold is greater than. Incidentally, may be set a plurality of threshold values, the weighting value W _i may be stepwise changed. Alternatively, a calculation formula for linearly calculating the weighted received value W _i from the output active power P may be set, and a calculation result of the calculation formula may be set.

According to the fourth embodiment, when the output active power P of the inverter device A is large, the weighting value _Wi is changed to a small value. Thereby, the adjustment amount of the output active power of the said inverter apparatus A becomes small, and output active power is adjusted. Moreover, also in 4th Embodiment, there can exist an effect similar to 1st Embodiment.

  When the inverter device A participates in the adjustment (suppression) of the active power only when the system frequency increases (that is, when the inverter device A does not participate in the adjustment (increase) of the active power when the system frequency decreases), On the contrary, when the output active power P is large, the adjustment amount (suppression amount) may be increased. That is, when the output active power P is large, there is no room for the capacity of the inverter device A, so the adjustment amount (suppression amount) is increased, and when the output active power P is small, the adjustment amount (suppression amount) is decreased. .

Incidentally, it is also possible to change the weighting value W _i by the generator of the DC power source 1. Further, when the DC power source 1 is a solar cell, the weighting value W _i is determined by the amount of solar radiation, and when the DC power source 1 is an apparatus that converts AC power generated by a wind turbine generator or the like into DC power and outputs it, the weight value W _i May be changed. Further, when the inverter device A is an inverter device of the storage battery, the charging amount of the battery, may be changed weighting value W _i. For example, the weighting value W _i may be increased when there is remaining charge capacity. Further, it is also possible to change the weighting value W _i in accordance with the power sale price.

  In the said 1st-4th embodiment, although the case where the control circuit which concerns on this invention was used for the inverter apparatus linked to an electric power grid | system was demonstrated, it is not restricted to this. For example, you may make it use the control circuit which concerns on this invention as a control circuit of the inverter apparatus used in the power plant (for example, mega solar) which performs solar power generation, or the power plant (wind farm) which performs wind power generation. In these cases, fluctuations in the system frequency in the mega solar or wind farm can be suppressed by adjusting the active power in cooperation with each inverter device.

  The control circuit, inverter device, power system, and control method according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the control circuit, the inverter device, the power system, and the control method according to the present invention can be varied in design in various ways.

A, A1 to A5 Inverter device 1 DC power supply 2 Inverter circuit 3 Control circuit 30 Reactive power control unit 31 Input voltage control unit (active power control means)
32 system frequency control unit 33 cooperative correction value generation unit 331 calculation unit 332 multiplier 333 integrator 34 adder 35 current control unit 351 three-phase / two-phase conversion unit 352 rotational coordinate conversion unit 353, 354 LPF
355, 356 PI control unit 357 Static coordinate conversion unit 358 Two-phase / three-phase conversion unit 36 Command signal generation unit 37 PWM signal generation unit 38 Weighting unit 39 Communication unit 40 System frequency detection unit 41 Temperature detection unit 42, 42 ', 42 ”Weight value setting unit 43 Clock unit 44 Active power calculation unit 4 Current sensor 5 Voltage sensor 6 DC voltage sensor B Power system

Claims (15)

In a power system in which a plurality of inverter devices that are not in a master-slave relationship are connected in parallel, a control circuit that controls an inverter circuit included in each inverter device,
Active power control means for generating an active power compensation value for controlling the active power output or input by the inverter device;
A system frequency detecting means for detecting the system frequency;
System frequency control means for generating a compensation value for controlling the system frequency to a target value;
Cooperative correction value generation means for generating a correction value for cooperation with each of the inverter devices;
Adding means for calculating a correction compensation value by adding the correction value to the compensation value;
PWM signal generating means for generating a PWM signal based on a value obtained by adding the correction compensation value to the active power compensation value;
Weighting means for weighting the correction compensation value;
Communication means for communicating with at least one other inverter device;
With
The communication means transmits a weighted correction compensation value to the other inverter device,
The cooperative correction value generation means generates the correction value using a calculation result based on the weighted correction compensation value and the reception compensation value received by the communication means from the other inverter device.
A control circuit characterized by that. The cooperative correction value generating means
A calculation means for performing a calculation based on the weighted correction compensation value and the reception compensation value;
Integrating means for calculating the correction value by integrating the calculation result output by the calculating means;
The control circuit according to claim 1, comprising: The calculation means subtracts the weighted correction compensation value from the reception compensation value, and calculates the calculation result by adding all the subtraction results.
The control circuit according to claim 2. The arithmetic means subtracts the weighted correction compensation value from the reception compensation value, adds all the subtraction results, and divides by the number of other inverter devices with which the communication means is communicating. , Calculate the calculation result,
The control circuit according to claim 2. The calculating means subtracts the weighted correction compensation value from the reception compensation value, adds all the subtraction results, and multiplies the weighted correction compensation value to calculate the calculation result.
The control circuit according to claim 2. The calculation means calculates the calculation result by subtracting the reception compensation value from the weighted correction compensation value, adding all the subtraction results, and multiplying by the square of the weighted correction compensation value. To
The control circuit according to claim 2. The weighting unit performs weighting by dividing the correction compensation value by a preset weighting value.
The control circuit according to claim 1. Temperature detecting means for detecting the temperature of the inverter circuit;
Weighting value setting means for setting a weighting value corresponding to the temperature;
Further comprising
The weighting unit performs weighting by dividing the correction compensation value by a weighting value set by the weighting value setting unit.
The control circuit according to claim 1. Clock means for outputting the date or time;
A weighting value setting means for storing a weighting value in association with the date or time, and for setting a weighting value corresponding to the date or time output by the clock means;
Further comprising
The weighting unit performs weighting by dividing the correction compensation value by a weighting value set by the weighting value setting unit.
The control circuit according to claim 1. Active power calculating means for calculating output active power of the inverter circuit;
Weighting value setting means for setting a weighting value corresponding to the output active power;
Further comprising
The weighting unit performs weighting by dividing the correction compensation value by a weighting value set by the weighting value setting unit.
The control circuit according to claim 1. The active power control means limits the power input to the inverter device to a state less than the maximum state,
The control circuit according to claim 1.   The control circuit according to claim 1, wherein the communication unit switches a communication partner based on a system frequency detected by the system frequency detection unit.   An inverter device comprising the control circuit according to claim 1 and an inverter circuit.   A power system comprising a plurality of inverter devices according to claim 13 connected in parallel. In a power system in which a plurality of inverter devices that are not in a master-slave relationship are connected in parallel, a control method for controlling the inverter circuit of each inverter device,
A first step of generating an active power compensation value for controlling the active power output or input by the inverter device;
A second step of generating a compensation value for controlling the system frequency detected by the system frequency detection means to a target value;
A third step of generating a correction value for cooperating with each inverter device;
A fourth step of calculating a correction compensation value by adding the correction value to the compensation value;
A fifth step of generating a PWM signal based on the active power compensation value plus the correction compensation value;
A sixth step of weighting the correction compensation value;
A seventh step of transmitting the weighted correction compensation value to at least one other inverter device;
An eighth step of receiving a value transmitted by the other inverter device as a reception compensation value;
Is performed by each inverter device,
The third step generates the correction value using a calculation result based on the weighted correction compensation value and the reception compensation value received in the eighth step.
A control method characterized by that.