Distributed power management device

Abstract

A distributed power management device includes: a communication circuit that communicates with a system management device and a plurality of distributed power sources; an operation plan creation circuit that generates a power target value for each distributed power source based on information received by the communication circuit and capacities of the plurality of distributed power sources; and a control parameter generation circuit that generates a control parameter for a virtual synchronous generator control of a static inverter installed in each distributed power source or information required for generation of the control parameter. The communication circuit is configured to receive at least one of measurement information of each distributed power source and an instruction value from the system management device, and transmit a control instruction to each distributed power source. The control parameter generation circuit generates the control parameter or the information required for generation of the control parameter based on the information received by the communication circuit, the capacities of the plurality of distributed power sources, and the power target value for each distributed power source, and outputs the generated control parameter or the information required for generation of the control parameter to each distributed power source via the communication circuit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a distributed power management device. BACKGROUND

[0002] In recent years, in order to reduce environmental load, renewable energy using devices (hereinafter also referred to as "energy creation device") such as solar cells are accelerated to be introduced. In addition, in order to cope with power shortages and the like after the Great East Japan Earthquake disaster, systems equipped with energy storage devices (hereinafter also referred to as "energy storage device") such as storage batteries, or systems and the like that combine energy creation devices and energy storage devices are being developed. In these systems, in order to connect the energy creation device and the energy storage device to an alternating current system, a static inverter is used.

[0003] On the other hand, in the power system, with an increase in the amount of power generation using renewable energy, from the viewpoint of reducing power generation costs including management costs, it is predicted that thermal power plants, which are adjustment forces for power generation in response to demand fluctuations, will be gradually closed in the future. However, synchronous generators in thermal power plants have a function of suppressing fluctuations in system frequency (inertial force, synchronizing force, etc.) in the event of fluctuations in system frequency. Therefore, as thermal power plants are gradually closed, synchronous generators are gradually reduced, so there is a concern that it will be difficult to ensure the stability of the power system.

[0004] In order to solve the above problem, development of control technology of a virtual synchronous generator having a function of a synchronous generator for a static inverter is being developed. For example, in Japanese Patent Application Publication No. 2019-176584 (Patent Literature 1), a method of setting control parameters of a distributed power source (static inverter) installed with a virtual synchronous generator control is disclosed. Specifically, in Patent Literature 1, a method is disclosed in which control parameters for setting virtual inertia in a distributed power source are generated from either a required inertia value required from a system operator or a virtual inertia value calculated based on the specifications and operating state of the distributed power source.

[0005] PRIOR ART DOCUMENTS

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2019-176584 SUMMARY

[0007] According to the control parameter generation method described in the above Patent Literature 1, although it is possible to ensure the inertia force of the system intended by the system manager, it is not possible to ensure the proportional distribution of the power shared by each distributed power source due to fluctuations in load or changes in the amount of power generation of the energy creation device.

[0008] For example, consider a case where batteries to which virtual synchronous generator control is installed are connected to a 2-system as a distributed power source. The capacities of the batteries and the capacities of the static inverters are the same, and the ratio of the state of charge (SOC) at the current time point is 2: 1. In this case, in the operation plan (charge and discharge plan) of the batteries, the ratio of the discharge power target values of the respective batteries is also allocated as 2: 1 as the ratio of the SOC.

[0009] Here, when the load of the entire system increases, the virtual synchronous generator control is executed in each battery, and the increased power is proportionally allocated to be output by the 2 batteries. At this time, in a case where the control parameters of the virtual synchronous generator control of the 2 batteries are the same, each battery additionally outputs the same amount of power.

[0010] However, in the operation plan of the above-described batteries, the 2 batteries are planned to output power in accordance with the ratio of the SOC of both, and it is preferable that the increased power also be proportionally allocated in accordance with the ratio of the operation plan.

[0011] In the above-described Patent Document 1, the control parameters are determined only with the inertial force of the system required by the system operator, so in a case where excess or insufficient power occurs when the load proportionally allocated by the plurality of distributed power sources is changed or the generated power of the energy creation device is changed, the proportionally allocated power is proportionally allocated in accordance with the virtual inertia of each distributed power source. Therefore, there is a problem that the excess or insufficient power is proportionally allocated in accordance with a different ratio than the proportionally allocated ratio assumed in the original operation plan.

[0012] Generally, the power target value (operation plan) proportionally allocated to the plurality of distributed power sources (a case where virtual synchronous generator control is assumed to be installed to the static inverter of the system battery system for simplicity of explanation) is proportionally allocated in accordance with the capacity of each battery and the SOC and the capacity of the static inverter, and the like. Specifically, in the case of discharge, when the battery capacity and the capacity of the static inverter are the same between the plurality of batteries, a large amount of power is allocated to the battery with a high SOC. This is because, in a case where, for example, the charge power of one of the 2 batteries becomes zero (SOC = 0), the inertial force of the system is thereafter maintained with the remaining one battery, so the virtual inertial force actually provided by the static inverter becomes half. Therefore, in a case where the power proportionally allocated to the plurality of batteries is determined, it is necessary to proportionally allocate the power in such a manner that the SOC of each battery becomes substantially zero (full charge in the case of charge) at the same time.

[0013] In particular, in a case where a microgrid or the like is configured using a plurality of distributed power sources such as storage batteries installed with virtual synchronous generator control, when the power supplied to the system is rapidly changed due to a rapid change in load or a rapid change in the amount of sunlight, there is a problem that the proportional distribution of power in each of the distributed power sources cannot be performed as intended.

[0014] The present disclosure was completed in order to solve the above-described problem points, and aims to generate, in a power system in which a plurality of distributed power sources having a static inverter installed with virtual synchronous generator control are interconnected, control parameters of the virtual synchronous generator control that enable each of the distributed power sources to proportionally distribute excess or insufficient power in a manner that the ratio to a power target value becomes equal even in a case where a variation in power consumption of a load or a variation in power generation of a power generation device occurs.

[0015] In one aspect of the present disclosure, a distributed power source management device manages a plurality of distributed power sources interconnected with a power distribution system. The plurality of distributed power sources each have a static inverter installed with virtual synchronous generator control. The distributed power source management device includes a communication circuit that communicates with a system management device that manages the power distribution system and the plurality of distributed power sources, an operation plan creation circuit that generates a power target value of each of the distributed power sources based on information received by the communication circuit and capacities of the plurality of distributed power sources, and a control parameter generation circuit that generates control parameters for the virtual synchronous generator control in each of the distributed power sources or information required for generation of the control parameters. The communication circuit is configured to receive at least one of measurement information of each of the distributed power sources and an instruction value from the system management device, and transmit a control instruction to each of the distributed power sources. The control parameter generation circuit generates the control parameters or the information required for generation of the control parameters based on the information received by the communication circuit, the capacities of the plurality of distributed power sources, and the power target value of each of the distributed power sources, and outputs the generated control parameters or the information required for generation of the control parameters to each of the distributed power sources via the communication circuit.

[0016] According to the present disclosure, proportional distribution of power in a plurality of distributed power sources can be performed as intended even in a case where a variation in power consumption of a load or a variation in power generation of a power generation device occurs. Specifically, excess or insufficient power can be proportionally distributed in a ratio equal to the ratio of a power target value at the time of creation of an operation plan of the distributed power source. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a block diagram illustrating a configuration of a power distribution system according to Embodiment 1.

[0018] Figure 2This is a block diagram used to further illustrate the structure of a portion of the equipment and power distribution system involved in Embodiment 1, including a battery connected to the power distribution system.

[0019] Figure 3 This is a block diagram of the CEMS involved in Implementation Method 1.

[0020] Figure 4 This is a block diagram of the operation planning and production circuit within the CEMS according to Implementation Method 1.

[0021] Figure 5 This is a block diagram of the control parameter generation circuit within the CEMS involved in Implementation Method 1.

[0022] Figure 6 yes Figure 1 The diagram shows a block structure of a power conversion device for a megawatt-class solar power generation system.

[0023] Figure 7 yes Figure 1 The diagram shown is a block diagram of the power conversion device for the battery in the system.

[0024] Figure 8 This is a block diagram illustrating the structure of the first control circuit that controls the first DC / DC converter of the power conversion device for megawatt-level solar power generation equipment.

[0025] Figure 9 This is a block diagram illustrating the structure of the second control circuit that controls the first DC / AC converter of the power conversion device for megawatt-level solar power generation equipment.

[0026] Figure 10 This is a block diagram illustrating the structure of the third control circuit that controls the second DC / DC converter of the battery power conversion device.

[0027] Figure 11 This is a block diagram illustrating the structure of the fourth control circuit that controls the second DC / AC converter of the battery power conversion device.

[0028] Figure 12 This is an explanation Figure 11 The diagram shows the structure of the AC frequency detection circuit.

[0029] Figure 13 This is an explanation Figure 11 The diagram shows the structure of the inverter voltage control circuit.

[0030] Figure 14 This is an explanation Figure 11 The diagram shows a block diagram of an example of the structure of a virtual synchronous generator control circuit.

[0031] Figure 15is a description Figure 14 is a block diagram showing the structure of a governor control circuit.

[0032] Figure 16 is a description Figure 14 is a block diagram showing the structure of a particle system operation circuit.

[0033] Figure 17 is a graph for explaining a region covered by the virtual synchronous generator control mounted to the battery power conversion device according to Embodiment 1.

[0034] Figure 18 is a graph showing an example of a relationship between a speed adjustment rate and a system frequency when a load is abruptly changed in the virtual synchronous generator control mounted to the battery power conversion device according to Embodiment 1.

[0035] Figure 19 is a graph showing an example of a relationship between a braking coefficient and a system frequency when a load is abruptly changed in the virtual synchronous generator control mounted to the battery power conversion device according to Embodiment 1.

[0036] Figure 20 is a graph showing an example of a ΔP / ΔF characteristic of the virtual synchronous generator control mounted to the battery power conversion device according to Embodiment 1.

[0037] Figure 21 is a graph showing a response waveform of a frequency of a system voltage output from a static inverter when a load is abruptly changed in the virtual synchronous generator control mounted to the battery power conversion device according to Embodiment 1.

[0038] Figure 22 is a graph showing a response waveform of a root mean square value of an alternating current output from each static inverter section when a load is abruptly changed in a stand-alone system configured using two battery power conversion devices each of which is mounted with a conventional virtual synchronous generator control.

[0039] Figure 23 is a graph showing a response waveform of a frequency of a system voltage output from each static inverter section when a load is abruptly changed in a stand-alone system configured using two battery power conversion devices each of which is mounted with a conventional virtual synchronous generator control.

[0040] Figure 24 is a graph showing an example of a ΔP / ΔF characteristic of a first power conversion device mounted with a conventional virtual synchronous generator control.

[0041] Figure 25is a graph showing one example of the ΔP / ΔF characteristic of the second power conversion device installed with the conventional virtual synchronous generator control.

[0042] Figure 26 is a graph showing one example of the ΔP / ΔF characteristic of the second power conversion device installed with the virtual synchronous generator control according to Embodiment 1.

[0043] Figure 27 is a graph showing one example of the reference ΔP / ΔF characteristic of the power conversion device installed with the virtual synchronous generator control according to Embodiment 1.

[0044] Figure 28 is a graph for explaining the operation of the ΔP / ΔF characteristic of the power conversion device in the case where the power target value is made different using the reference ΔP / ΔF characteristic of the power conversion device installed with the virtual synchronous generator control according to Embodiment 1.

[0045] Figure 29 is a graph for explaining the operation of the ΔP / ΔF characteristic of the power conversion device in the case where the capacity of the static inverter is made different using the reference ΔP / ΔF characteristic of the power conversion device installed with the virtual synchronous generator control according to Embodiment 1.

[0046] Figure 30 is a graph showing one example of the ΔP / ΔF characteristic of two power conversion devices installed with the virtual synchronous generator control according to Embodiment 1, which differ in the inverter capacity and the power target value.

[0047] Figure 31 is a graph showing the response waveform of the effective value of the alternating-current power output from the two power conversion devices having the ΔP / ΔF characteristics shown in Figure 30

[0048] Figure 32 is a timing chart of the usual operation of the distributed power management device centered on the CEMS shown in Figure 1

[0049] is a flowchart explaining the control processing of the CEMS shown in Figure 33 Figure 1 is a flowchart explaining the detailed operation of the operation plan making processing (S05) of

[0050] Figure 34 Figure 33 is a flowchart explaining the detailed operation of the control parameter generation processing (S056) of the virtual synchronous generator of

[0051] Figure 35 Figure 34 ​​​​​

[0052] Figure 36 is a flowchart illustrating detailed actions of the ΔP / ΔF characteristic generation process (S0562) of Figure 35

[0053] Figure 37 is a flowchart illustrating detailed actions of the ΔP / ΔF characteristic generation process (S0563) of Figure 35

[0054] Figure 38 is a flowchart illustrating detailed actions of the control parameter generation process (S0564) of Figure 35

[0055] Figure 39 is a flowchart illustrating detailed actions of the operation plan correction process (S09) of Figure 33

[0056] Figure 40 is a flowchart illustrating actions of the battery power conversion device.

[0057] Figure 41 is a flowchart illustrating detailed actions of the control process (S204) of the second DC / AC converter. Figure 40

[0058] is a block diagram of the control parameter generation circuit in the CEMS according to Embodiment 2. Figure 42

[0059] is a flowchart illustrating detailed actions of the virtual synchronous generator control parameter generation process (S056) of Figure 43 Figure 34

[0060] Figure 44 is a flowchart illustrating actions of the battery power conversion device according to Embodiment 2.

[0061] Figure 45 is a diagram for explaining the concept of the virtual synchronous generator control technology. DETAILED DESCRIPTION

[0062] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. Furthermore, the same or equivalent portions in the drawings are added with the same symbol, and the description thereof will not be repeated.

[0063] Embodiment 1.

[0064] (Structure example of power distribution system)

[0065] ​​​​​​First, a configuration example of a power distribution system to which the distributed power management apparatus according to Embodiment 1 is applied will be described. Further, a three-phase system is exemplified in Embodiment 1, but the power distribution system can also be a single-phase system.

[0066] Figure 1 is a block diagram showing a configuration example of the power distribution system 24 according to Embodiment 1. As shown in Figure 1 , the power distribution system 24 receives supply of electric power from the substation 20. In the power distribution system 24, a plurality of step voltage regulators (SVRs) 23a to 23c are provided. The plurality of SVRs 23a to 23c are connected in series with respect to the flow of electric power. The plurality of SVRs 23a to 23c are connected with the building 112, the apartment 113, the towns A to D 100a to 100d, the factory 110, the power conversion apparatus 27 for the mega solar power generation equipment, the power conversion apparatuses 41a to 41c for the system storage batteries, the synchronous generators 30a, 30b. In the following description, the SVRs 23a to 23c will also be collectively referred to as "SVRs 23". Further, the power conversion apparatuses 41a to 41c will also be collectively referred to as "power conversion apparatuses 41".

[0067] A plurality of voltage meters 22a, 22e, 22f, 22i, 22j, 22x are disposed in the power distribution system 24. Hereinafter, the voltage meters 22a, 22e, 22f, 22i, 22j, 22x will also be collectively referred to as "voltage meters 22". The measured values of the respective voltage meters 22 are transmitted to a distribution automation system 21 (hereinafter also referred to as "DSO 21") at a predetermined cycle. The DSO 21 corresponds to one embodiment of a "system management apparatus" that manages the power distribution system 24.

[0068] The information of the tap position of the SVRs 23, the primary-side voltage, and the secondary-side voltage is sent to the DSO 21. In Embodiment 1, the SVRs 23 notify the tap position information, the primary-side voltage, and the secondary-side voltage information at a predetermined cycle, and the tap position information, the primary-side voltage, and the secondary-side voltage information are notified non-periodically at the time of tap switching.

[0069] The CEMS 31 collects various measurement values and the like from each demander (towns 100a to 100d, factory 110, building 112, and apartment 113), power conversion device 27, synchronous generators 30a and 30b, and power conversion devices 41a to 41c at a predetermined cycle. The CEMS 31 notifies the collected data to the DSO 21 according to a request from the DSO 21. Further, the consumed power of the demanders in the towns 100a to 100d, the generated power of the energy creating equipment are measured by the smart meters (not shown) provided in each demander. The CEMS 31 collects the measurement values of the smart meters at a predetermined cycle (for example, 30 minutes cycle). The CEMS 31 corresponds to one embodiment of the "distributed power management device".

[0070] The power conversion device 27 is connected to the megawatt solar power generation equipment 26. The power conversion devices 41a to 41c are connected to the system storage batteries 40a to 40c, respectively. The storage batteries 40a to 40c are large capacity storage batteries which can be connected to the power distribution system 24. In the following description, the storage batteries 40a to 40c are also referred to as "storage batteries 40" in the case of collectively referring to the storage batteries 40a to 40c.

[0071] Figure 2 is a block diagram for further explaining Figure 1 the structure of the power distribution system 24 shown in

[0072] As shown in Figure 2 , the power distribution system 24 is connected to the load 600, power conversion device 41, and storage battery 40. Further, in order to simplify the description, the impedance 29 of the power distribution system 24 is represented by a centralized system in Figure 2 . The impedance 29 of the power distribution system 24 is set to be composed of a reactor component and a resistance component.

[0073] (1) CEMS 31

[0074] Figure 3 is a block diagram showing the structure of the CEMS 31 shown in Figure 1

[0075] As shown in Figure 3 , the CEMS 31 has a communication circuit 11, storage circuit 12, control parameter generation circuit 13, operation plan making circuit 14, transmission data generation circuit 15, and control circuit 16.

[0076] ​The communication circuit 11 communicates with the DSO 21, each demander (towns 100a to 100d, factory 110, building 112, apartment 113), power conversion device 27, synchronous generators 30a, 30b, and power conversion devices 41a to 41c via the communication line 25.

[0077] The storage circuit 12 stores various information acquired via the communication circuit 11. Among the various information, there are included measurement results and state information of each distributed power source, and the like.

[0078] The control parameter generation circuit 13 generates control parameters for the virtual synchronous generator control installed in each of the power conversion devices 41a to 41c.

[0079] The operation plan making circuit 14 makes an operation plan of the power conversion devices 41a to 41c in accordance with a control instruction from the DSO 21. The operation plan of the power conversion devices 41a to 41c includes a charge / discharge plan (power target value) of the corresponding storage batteries 40a to 40c. In Embodiment 1, the operation plan making circuit 14 makes an operation plan for 24 hours with an interval of 30 minutes.

[0080] Further, the operation plan making circuit 14 determines whether or not the operation plan needs to be corrected in accordance with measurement results of the power conversion devices 41a to 41c, SOC information of the storage batteries 40a to 40c, and the like collected in units of 5 minutes. In a case where it is determined that the operation plan needs to be corrected, the operation plan making circuit 14 corrects the operation plan for a period until the next control instruction from the DSO 21 is notified.

[0081] The transmission data generation circuit 15 stores the control parameters for the virtual synchronous generator control generated by the control parameter generation circuit 13 and the operation plan output from the operation plan making circuit 14. The transmission data generation circuit 15 outputs the stored data to the communication circuit 11 in response to a transmission instruction from the control circuit 16. The communication circuit 11 transmits the data output from the transmission data generation circuit 15 to the communication line 25 in accordance with a control signal output from the control circuit 16.

[0082] The control circuit 16 is a control circuit for managing the distributed power sources connected to the power distribution system 24. The control circuit 16 manages the actions of the communication circuit 11, the storage circuit 12, the control parameter generation circuit 13, the operation plan making circuit 14, and the transmission data generation circuit 15.

[0083] (1-1) Operation plan making circuit 14

[0084] Figure 4 is a block diagram showing the structure of the operation plan making circuit 14 shown in Figure 3 ​

[0085] As Figure 4 shown, the operation plan creation circuit 14 includes a storage battery operation plan creation circuit 141, a generated power prediction circuit 142, a consumed power prediction circuit 143, a storage battery operation plan correction circuit 144, a management circuit 145, and a management circuit 146.

[0086] The storage battery operation plan creation circuit 141 creates an operation plan (a power target value) of the power conversion device 41a, 41b, 41c, based on information on a control instruction notified from the DSO 21, information on a prediction result of the generated power of the mega solar power plant 26 predicted by the generated power prediction circuit 142, and information on a prediction result of the consumed power of the demand side predicted by the consumed power prediction circuit 143. Further, the control instruction notified from the DSO 21 to the storage battery operation plan creation circuit 141 includes a planned value of the power consumed on the downstream side of the substation 20 (a supplied power to the distribution system 24). The planned value of the supplied power includes a planned value of 24 hours in units of 30 minutes.

[0087] The generated power prediction circuit 142 acquires 24 hours of weather forecast information from a weather forecast server not shown via the communication circuit 11. The generated power prediction circuit 142 predicts the generated power of the mega solar power plant 26 based on the acquired weather forecast information and information of a database (not shown) prepared for predicting the generated power.

[0088] The consumed power prediction circuit 143 predicts a total value of the consumed power of each demand side based on clock information (date, day of the week, time) inside the CEMS 31 and information of a database (not shown) prepared for predicting the consumed power.

[0089] The storage battery operation plan correction circuit 144 determines whether or not the operation plan needs to be corrected based on the charge and discharge power amount of the power conversion device 41a to 41c and the power target value information via the communication circuit 11. In a case where it is determined that the operation plan needs to be corrected, the storage battery operation plan correction circuit 144 generates a correction value of the operation plan.

[0090] The management circuit 145 manages creation of the operation plan of the distributed power source connected to the distribution system 24. The management circuit 145 stores the power target value (a charge power target value and a discharge power target value) of each storage battery 40 generated by the storage battery operation plan creation circuit 141 and the storage battery operation plan correction circuit 144. The management circuit 145 outputs the power target value to the control parameter generation circuit 13 and the transmission data generation circuit 15 based on a control signal output from the management circuit 146.

[0091] The management circuit 146 manages the operation of the battery operation plan creation circuit 141, the power generation power prediction circuit 142, the power consumption prediction circuit 143, the battery operation plan correction circuit 144, and the management circuit 145.

[0092] (1-2) Control parameter generation circuit 13

[0093] Figure 5 is a block diagram showing the structure of the control parameter generation circuit 13. Figure 3

[0094] As shown in FIG. 1, the control parameter generation circuit 13 includes a reference ΔP / ΔF characteristic calculation circuit 131, a ΔP / ΔF characteristic calculation circuit 132, a control parameter generation circuit 133, a virtual synchronous generator model 134, a management circuit 135, and a control circuit 136. Figure 5 The reference ΔP / ΔF characteristic calculation circuit 131 calculates a reference ΔP / ΔF characteristic based on capacity information of the static inverter (second DC / AC converter 408) of the power conversion device 41a to 41c.

[0095] The ΔP / ΔF characteristic calculation circuit 132 calculates a ΔP / ΔF characteristic based on the above-mentioned reference ΔP / ΔF characteristic and power target value information created by the operation plan creation circuit 14 (141).

[0096] Figure 4

[0097] The control parameter generation circuit 133 generates a control parameter for virtual synchronous generator control using the virtual synchronous generator model 134 based on the above-mentioned ΔP / ΔF characteristic, information associated with the power distribution system 24 (system frequency (reference frequency Fref), ΔFmax, etc.) notified from the DSO 21, and capacity of the static inverter (second DC / AC converter 408).

[0098] The virtual synchronous generator model 134 calculates a speed adjustment rate Kgd and a brake coefficient Dg using information input from the control parameter generation circuit 133. The control parameter generation circuit 133 calculates an inertia constant M using the brake coefficient Dg.

[0099] The management circuit 135 manages the control parameter for virtual synchronous generator control. The management circuit 135 stores and manages the control parameter output from the control parameter generation circuit 133, the ΔP / ΔF characteristic calculated by the ΔP / ΔF characteristic calculation circuit 132, and information such as the power target value Pref to a not-illustrated memory.

[0100] ​​​The control circuit 136 manages the operations of the reference ΔP / ΔF characteristic calculation circuit 131, the ΔP / ΔF characteristic calculation circuit 132, the control parameter generation circuit 133, the virtual synchronous generator model 134, and the management circuit 135.

[0101] (2) Power conversion device 27

[0102] Figure 6 is a block diagram illustrating the structure of the power conversion device 27 shown in Figure 1

[0103] As shown in Figure 6 , the power conversion device 27 has a voltage meter 201, 206, 210, a current meter 202, 207, 211, a first DC / DC converter 203, a first control circuit 204, a direct current bus 205, a first DC / AC converter 208, a second control circuit 209, and a communication interface (I / F) 212.

[0104] The voltage meter 201 measures a direct current voltage output from the megawatt solar power plant 26. The current meter 202 measures a direct current output from the megawatt solar power plant 26.

[0105] The first DC / DC converter 203 converts a first direct current voltage output from the megawatt solar power plant 26 into a second direct current voltage. The first control circuit 204 controls the first DC / DC converter 203.

[0106] The direct current bus 205 supplies the second direct current voltage output from the first DC / DC converter 203 to the first DC / AC converter 208. The voltage meter 206 measures a voltage of the direct current bus 205. The current meter 207 measures a direct current output from the first DC / DC converter 203.

[0107] The first DC / AC converter 208 converts a direct current power output from the first DC / DC converter 203 into an alternating current power. The second control circuit 209 controls the first DC / AC converter 208.

[0108] The voltage meter 210 measures an alternating current voltage output from the first DC / AC converter 208. The current meter 211 measures an alternating current output from the first DC / AC converter 208. The communication I / F 212 performs communication between the power conversion device 27 and the CEMS 31.

[0109] (3) Power conversion device 41

[0110] Figure 7 is a block diagram illustrating the structure of the power conversion device 41 shown in Figure 1

[0111] As shown in Figure 7 ​​As shown, the power conversion device 41 includes voltmeters 401, 406, and 410, ammeters 402, 407, and 411, a second DC / DC converter 403, a third control circuit 404, a DC bus 405, a second DC / AC converter 408, a fourth control circuit 409, and a communication I / F 412.

[0112] Voltmeter 401 measures the DC voltage output from battery 40. Ammeter 402 measures the DC current output from battery 40.

[0113] The second DC / DC converter 403 converts the third DC voltage output from the battery 40 into a fourth DC voltage. The third control circuit 404 controls the second DC / DC converter 403.

[0114] DC bus 405 supplies the DC voltage output from the second DC / DC converter 403 to the second DC / AC converter 408. Voltmeter 406 measures the voltage of DC bus 405. Ammeter 407 measures the DC current output from the second DC / DC converter 403.

[0115] The second DC / AC converter 408 converts the DC power output from the second DC / DC converter 403 into AC power. The fourth control circuit 409 controls the second DC / AC converter 408.

[0116] Voltmeter 410 measures the AC voltage output from the second DC / AC converter 408. Ammeter 411 measures the AC current output from the second DC / AC converter 408. Communication I / F 412 enables communication between the power conversion device 41 and CEMS 31.

[0117] Furthermore, in the first DC / DC converter 203 ( Figure 6 ) and the second DC / DC converter 403 ( Figure 7 In the first DC / AC converter 208, a known DC / DC converter can be appropriately used. Figure 6 ) and the second DC / AC converter 408 ( Figure 7 In this embodiment, a known inverter can be used. The first DC / AC converter 208 and the second DC / AC converter 408 each correspond to an embodiment of a "static inverter". The second control circuit 209 and the fourth control circuit 409 correspond to an embodiment of a "static inverter control unit".

[0118] (2-1) First control circuit 204

[0119] Figure 8 This is an explanation Figure 6 The block diagram of the structure of the first control circuit 204 shown is shown.

[0120] As Figure 8 illustrated in FIG. 2, the first control circuit 204 has an MPPT (Maximum Power Point Tracking) control circuit 51, a voltage control circuit 52, a first switching circuit 53, and a fifth control circuit 54.

[0121] The MPPT control circuit 51 performs so-called MPPT (Maximum Power Point Tracking) control based on the measurement values of the voltage meter 201 and the current meter 202. The MPPT control circuit 51 searches for the maximum power point of the mega solar power generation device 26 in order to extract the generated power of the mega solar power generation device 26 to the maximum. Specifically, the MPPT control circuit 51 generates a control command value of the first DC / DC converter 203 in order to control the direct current voltage measured by the voltage meter 201 to the voltage corresponding to the maximum power point.

[0122] The voltage control circuit 52 generates a control command value of the first DC / DC converter 203 for maintaining the direct current voltage (second direct current voltage) of the direct current bus 205 at a predetermined target voltage based on the measurement value of the voltage meter 206.

[0123] The fifth control circuit 54 outputs the control parameters and control target values of the MPPT control circuit 51 and the voltage control circuit 52, and manages the generated state of the mega solar power generation device 26 and the like. The fifth control circuit 54 also outputs a control signal of the first switching circuit 53.

[0124] The first switching circuit 53 selectively outputs either of the outputs of the MPPT control circuit 51 and the voltage control circuit 52 as a control command value of the first DC / DC converter 203 in accordance with the control signal from the fifth control circuit 54.

[0125] The first DC / DC converter 203 is controlled in either an MPPT mode or a voltage control mode. In the MPPT mode, the first switching circuit 53 outputs the control command value generated by the MPPT control circuit 51. In the voltage control mode, the first switching circuit 53 outputs the control command value generated by the voltage control circuit 52.

[0126] (2-2) Second Control Circuit 209

[0127] Figure 9 is a block diagram illustrating Figure 6 the structure of the second control circuit 209 illustrated in FIG. 3.

[0128] As Figure 9 illustrated in FIG. 3, the second control circuit 209 has a phase detection circuit 61, a first sine wave generation circuit 62, a current control circuit 60, and a sixth control circuit 67.

[0129] The current control circuit 60 has a subtracter 63, a first PI control circuit 64, a multiplier 65, a subtracter 66, a second PI control circuit 68, and a first PWM converter 69. The current control circuit 60 performs a control mode that outputs electric power in synchronization with a system voltage. This control mode is a control method of a general electric power converter for solar power generation provided in a home.

[0130] The phase detection circuit 61 detects a phase of the alternating voltage from a waveform of the alternating voltage measured by the voltage meter 210 Figure 6 ).

[0131] The first sine wave generation circuit 62 generates a sine wave in synchronization with the waveform of the alternating voltage, based on the amplitude of the alternating voltage measured by the voltage meter 210 and the phase information detected by the phase detection circuit 61. Further, in Embodiment 1, the phase detection circuit 61 detects a zero-crossing point of the waveform of the alternating voltage, and detects the frequency of the alternating voltage from the detection result of the zero-crossing point. The phase detection circuit 61 outputs the detected frequency of the alternating voltage to the first sine wave generation circuit 62 together with the zero-crossing point information.

[0132] The current control circuit 60 generates a control command value for controlling the first DC / DC converter 208, based on the direct-current voltage of the direct-current bus 205 measured by the voltage meter 206 Figure 6 ). The subtracter 63 subtracts the direct-current voltage of the direct-current bus 205 measured by the voltage meter 206 from the target value of the direct-current bus voltage output from the sixth control circuit 67. The subtraction operation value obtained by the subtracter 63 is input to the first PI control circuit 64.

[0133] The multiplier 65 generates a current command value by multiplying the control command value output from the first PI control circuit 64 and the sine wave output from the first sine wave generation circuit 62.

[0134] The subtracter 66 calculates a deviation of the current command value output from the multiplier 65 from the current value of the alternating system measured by the current meter 211 Figure 6 ). The second PI control circuit 68 generates a control command value in such a manner that the deviation output from the subtracter 66 becomes zero, based on the control parameters (a proportional gain and an integral time) provided from the sixth control circuit 67. The second PI control circuit 68 outputs the generated control command value to the first PWM converter 69.

[0135] The second PI control circuit 68 generates a control command value in such a manner that the deviation output from the subtracter 66 becomes zero, based on the control parameters (a proportional gain and an integral time) provided from the sixth control circuit 67. The second PI control circuit 68 outputs the generated control command value to the first PWM converter 69.

[0136] The first PWM converter 69 generates a control command value by performing PWM control with respect to a control command value input from the second PI control circuit 68, and outputs the generated control command value to the first DC / AC converter 208.

[0137] The sixth control circuit 67 collects measurement results relating to the DC bus 205 output from the voltage meter 206 and the current meter 207, measurement results relating to the AC system output from the voltage meter 210 and the current meter 211, and state information of the first DC / DC converter 203 output from the first control circuit 204, and notifies the collected information to the CEMS 31 or the like via the communication I / F 212.

[0138] In addition, the sixth control circuit 67 notifies control parameters with respect to the first PI control circuit 64 and the second PI control circuit 68. The sixth control circuit 67 notifies information relating to active power and inactive power measured by an active voltage measurement unit (not shown) of the AC system to the CEMS 31 via the communication I / F 212. The sixth control circuit 67 notifies the measurement values of the active voltage and the active power of the AC system or the like to the fifth control circuit 54. The fifth control circuit 54 suppresses the rise of the system voltage by switching the control of the mega solar power generation device 26 from MPPT control to voltage control, for example, in a case where the effective value of the system voltage exceeds a predetermined value.

[0139] (3-1) Third Control Circuit 404

[0140] Figure 10 is a block diagram illustrating Figure 7 the structure of the third control circuit 404.

[0141] As Figure 10 illustrated, the third control circuit 404 has a charge control circuit 71, a discharge control circuit 72, a second switching circuit 73, and a seventh control circuit 74.

[0142] The charge control circuit 71 generates a control command value of the second DC / DC converter 403 when performing charge control of the storage battery 40.

[0143] The discharge control circuit 72 generates a control command value of the second DC / DC converter 403 when performing discharge control of the storage battery 40.

[0144] The seventh control circuit 74 outputs control parameters and control target values or the like with respect to the charge control circuit 71 and the discharge control circuit 72. The seventh control circuit 74 manages a charge power amount (SOC) of the storage battery 40, a charge power (charge current), a discharge power (discharge current), and the like. The seventh control circuit 74 outputs a control signal of the second switching circuit 73.

[0145] The second switching circuit 73 selectively outputs either of the outputs of the charge control circuit 71 and the discharge control circuit 72 as a control command value of the second DC / DC converter 403 in accordance with a control signal from the seventh control circuit 74. Specifically, the second switching circuit 73 outputs the control command value generated by the charge control circuit 71 when the charge of the battery 40 is instructed. On the other hand, the second switching circuit 73 outputs the control command value generated by the discharge control circuit 72 when the discharge of the battery 40 is instructed.

[0146] (3-2) Fourth Control Circuit 409

[0147] Figure 11 is a block diagram illustrating Figure 7 the structure of the fourth control circuit 409.

[0148] As Figure 11 illustrated, the fourth control circuit 409 has an AC frequency detection circuit 81, an active power calculation circuit 82, a virtual synchronous generator control circuit 83, an inverter current control circuit 84, an inverter voltage control circuit 85, a third switching circuit 86, and an eighth control circuit 87.

[0149] The AC frequency detection circuit 81 detects the phase of the AC voltage from the waveform of the AC voltage measured by the voltage meter 410 Figure 7 ) in the embodiment 1. Further, the detection method of the frequency of the AC voltage is not limited to the method using the detection result of the zero-crossing point.

[0150] The active power calculation circuit 82 calculates the active power using the information of the AC voltage and the AC current measured by the voltage meter 410 and the current meter 411 Figure 7 ) in the embodiment 1. Further, the calculation method of the active power is not limited to the above-described method, and for example, the DQ transformation or the like can be used to calculate the active power in the case where the AC system is a three-phase AC.

[0151] The virtual synchronous generator control circuit 83 adds the inertia force, the synchronization force, and the braking force that the synchronous generator has to the second DC / AC converter 408 (the static type inverter) in accordance with the frequency information of the AC voltage output from the AC frequency detection circuit 81 and the active power information output from the active power calculation circuit 82.

[0152] [Virtual synchronous generator control technology]

[0153] The following describes the virtual synchronous generator control technology.

[0154] A synchronous generator used typically in thermal power generation has a function of adjusting output power according to frequency (governor function), a function of maintaining angular velocity (inertia force), a function of attaining synchronization with system voltage (synchronization force), a function of adjusting voltage of a trunk system (AVR function: Automatic Voltage Regulation function), a function of continuing operation even when instantaneous decrease of AC system voltage occurs at the time of system trouble, and the like.

[0155] In the virtual synchronous generator control technology, the stationary inverter is caused to simulate functions that a synchronous generator has by controlling transient response of the stationary inverter. Specifically, three functions of the governor function, a function of simulating a mass system model based on a swing equation (dynamic characteristics of a rotating electric machine), and the AVR function are simulated.

[0156] In Embodiment 1, a case where the governor function and the function of simulating a mass system model based on a swing equation are installed to the second DC / AC converter 408 is specifically described. Figure 45 A conceptual diagram for explaining the virtual synchronous generator control technology is shown. Further, as to the AVR function that a synchronous generator has, it is mainly a function that is controlled according to an output voltage command or a reactive power command value notified from a higher system (CEMS 31 in Embodiment 1), so it is not installed in Embodiment 1. The following specifically describes the governor function and the function of simulating a mass system model based on a swing equation.

[0157] First, the governor function is described.

[0158] A governor in a power generation facility has a function of controlling output power of a generator by controlling output of a gas turbine or a steam turbine in thermal power generation and atomic power generation, and / or a guide vane of a water wheel in hydroelectric power generation. In an AC power system, when demand power exceeds supply power, frequency of system voltage decreases. In a thermal power generator or a hydroelectric power generator that can perform output control, the governor is caused to have a droop characteristic, so that the generator is controlled in such a manner that power generation power increases when frequency of system voltage decreases. On the other hand, the generator is controlled so that power generation power decreases when frequency of system voltage increases due to supply power exceeding demand power.

[0159] Figure 45 is a diagram schematically showing the governor function. As shown in Figure 45As shown, when the angular velocity ω of the synchronous generator increases, the valve that adjusts the energy inflow moves to the right, thereby reducing the energy supplied to the synchronous generator. Conversely, when the angular velocity ω of the synchronous generator decreases, the valve moves to the left, thereby increasing the energy supplied to the synchronous generator. Thus, the energy output from the synchronous generator can be controlled independently based on the frequency of the system voltage at this terminal (i.e., the angular velocity ω of the synchronous generator). Even when the synchronous generators perform the above actions independently, since the operation is managed according to the frequency of the system voltage, the load can be shared among multiple synchronous generators. Regarding the speed governor, a model constructed using a single-stage delay system is provided as a standard model from the Electrical Engineers of Japan.

[0160] In Implementation 1, the operation of the speed controller is described using a model composed of the above-described single-delay system, as shown in Equation (1).

[0161] -1 / {Kgd×(1+s×Tg)}…(1)

[0162] In equation (1), -1 / Kgd is the proportional gain of the speed controller (Kgd: speed regulation rate), and Tg is the time constant of the primary delay system (Tg: speed controller time constant).

[0163] Next, we will explain the functionality of simulating a particle system model based on the oscillating equation.

[0164] like Figure 45 As shown, the synchronous generator has a rotor with a unit inertia constant M. For example, in the case of a rapid decrease in the generated power of the megawatt-scale solar power generation equipment 26 due to a sharp change in solar irradiance, the insufficient power cannot be supplied instantaneously under the speed governor control described above. The synchronous generator converts the rotational energy stored in the rotor into electricity and outputs it to the AC system. At this time, when the angular velocity (rotational speed) of the rotor decreases, the energy supplied by the speed governor control increases, thereby balancing the demand for electricity and the supply of electricity. The following equation (2) shows the oscillation equation of the simulated particle system model (generator rotor). In the oscillation equation, the energy P is divided by the angular velocity ω and converted into torque T.

[0165] Tin-Tout=M×dω / dt+Dg×ω…(2)

[0166] Where Dg is the braking coefficient and M is the inertial constant.

[0167] In Implementation 1, the following situation is described: by substituting Equations (1) and (2) into the control of the static inverter (second DC / AC converter 408), the inertial force, synchronization force and braking force of the synchronous generator are simulated.

[0168] Returning to Figure 11 , the inverter current control circuit 84 generates a control command value for current control of the second DC / AC converter 408. Further, the inverter current control circuit 84 controls only the parameters different from the current control circuit 60 shown in FIG. 6, and the circuit structure and the operation are the same, so the detailed explanation is omitted. Figure 9

[0169] The inverter voltage control circuit 85 generates a control command value for voltage control of the second DC / AC converter 408.

[0170] The third switching circuit 86 switches the control command value from the inverter current control circuit 84 and the control command value from the inverter voltage control circuit 85 according to the output of the eighth control circuit 87.

[0171] The eighth control circuit 87 collects the measurement results relating to the DC bus 405 obtained by the voltage meter 406 and the current meter 407, the state information of the second DC / DC converter 403 output from the third control circuit 404, and the like, and notifies the collected information to the CEMS 31 and the like via the communication I / F 412.

[0172] In addition, the eighth control circuit 87 notifies the respective control parameters of the virtual synchronous generator control circuit 83, the inverter current control circuit 84, and the inverter voltage control circuit 85.

[0173] Further, the eighth control circuit 87 notifies the active voltage of the alternating current system measured by an active voltage measurement unit not shown, or the information of the active power and the inactive power measured by an active / inactive power measurement unit not shown of the alternating current system, to the CEMS 31 via the communication I / F 412. The eighth control circuit 87 notifies the measurement results of the active voltage of the alternating current system, the active power, and the like to the seventh control circuit 74.

[0174] (3-2-1) Alternating Current Frequency Detection Circuit 81

[0175] Figure 12 is a block diagram illustrating the structure of the alternating current frequency detection circuit 81 shown in FIG. 6. Figure 11 As shown in FIG. 7, the alternating current frequency detection circuit 81 has a phase detection circuit 810, a frequency detection circuit 811, and a second sine wave generation circuit 812.

[0176] Figure 12

[0177] ​​​The phase detection circuit 810 detects a zero-crossing point from a waveform of the system voltage output from the voltage meter 410. The phase detection method in the phase detection circuit 810 is not limited to the detection of the zero-crossing point. With regard to the detection of the zero-crossing point in the actual machine, an error occurs due to a detection error of the zero-crossing point of the voltage meter 410 (mainly, an offset error), an amplitude detection error of the voltage meter 410 (mainly, a linearity error), an error of a sampling period at the time of sampling the system voltage waveform, and the like. Further, when sampling is performed by a microcomputer or the like, an error of the sampling period can occur due to a deviation of time from the carrier interruption to the actual sampling.

[0178] The frequency detection circuit 811 detects the system frequency from the period of the zero-crossing point output from the phase detection circuit 810. Further, the method of detecting the system frequency is not limited to the method of detecting from the period of the zero-crossing point.

[0179] The second sine wave generation circuit 812 generates a sine wave synchronized with the system voltage on the basis of the detection result of the zero-crossing point in the phase detection circuit 810, the detection result of the frequency in the frequency detection circuit 811, and the amplitude of the system voltage output from the CEMS 31. The AC frequency detection circuit 81 outputs the detection result of the zero-crossing point (the timing of the detection of the zero-crossing point), the detection result of the frequency, and the sine wave information.

[0180] (3-2-2) Inverter Voltage Control Circuit 85

[0181] Figure 13 is a block diagram illustrating the structure of the inverter voltage control circuit 85 shown in Figure 11

[0182] As shown in Figure 13 , the inverter voltage control circuit 85 has a third sine wave generation circuit 851, a subtracter 852, a third PI control circuit 853, and a second PWM converter 854.

[0183] The inverter voltage control circuit 85 generates a control command value for controlling the second DC / AC converter 408 on the basis of the information of the frequency and the phase output from the virtual synchronous generator control circuit 83 Figure 11 , and the amplitude information of the system voltage output from the eighth control circuit 87 Figure 11 . Further, the amplitude information of the system voltage from the eighth control circuit 87 is input to the inverter voltage control circuit 85 via the second sine wave generation circuit 812.

[0184] The frequency and the phase from the AC frequency detection circuit 81 Figure 11 ​The sine wave information (information of frequency, phase, and amplitude) of the output voltage of the second DC / AC converter 408 is input to a third sine wave generation circuit 851. The third sine wave generation circuit 851 generates a target value of the alternating voltage output from the second DC / AC converter 408 in accordance with the input sine wave information.

[0185] A subtracter 852 calculates a deviation of the target value of the alternating voltage from the third sine wave generation circuit 851 from the voltage measured by the voltage meter 410, and outputs the calculated deviation to a third PI control circuit 853.

[0186] The third PI control circuit 853 generates a voltage command value by performing a PI (proportional integral) operation in such a manner that the input deviation becomes zero. The third PI control circuit 853 outputs the generated voltage command value to a second PWM converter 854. Further, the control parameters (control gain and integral time) in the third PI control circuit 853 are provided from the eighth control circuit 87.

[0187] The second PWM converter 854 performs PWM (Pulse Width Modulation) control using the voltage command value output from the third PI control circuit 853, thereby generating a control signal. The second PWM converter 854 outputs the generated control signal to the second DC / AC converter 408.

[0188] (3-2-3) Virtual synchronous generator control circuit 83

[0189] Figure 14 is a block diagram illustrating Figure 11 the structure of the virtual synchronous generator control circuit 83.

[0190] As Figure 14 illustrated, the virtual synchronous generator control circuit 83 has a subtracter 832, a governor control circuit 833, an adder 835, a subtracter 836, and a mass system operation circuit 837.

[0191] The subtracter 832 calculates a deviation of the measured frequency from the reference frequency Fref output from the eighth control circuit 87. The output of the subtracter 832 is input to the governor control circuit 833. The governor control circuit 833 generates a deviation value to be added to the power target value in accordance with the output of the subtracter 832. The detailed operation of the governor control circuit 833 will be described later.

[0192] The adder 835 generates a control power target value of the mass system operation circuit 837 by adding the deviation value output from the governor control circuit 833 and the power target value Pref input from the eighth control circuit 87.

[0193] Subtractor 836 calculates the deviation between the effective power input from effective power calculation circuit 82 and the target value of control power input from adder 835. The output of subtractor 836 is input to particle system operation circuit 837.

[0194] The particle system calculation circuit 837 calculates the frequency and phase of the system voltage output from the power conversion device 41 in such a way that the deviation output from the subtractor 836 is zero. Furthermore, in Embodiment 1, the control parameters (speed adjustment rate Kgd, governor time constant Tg, inertia constant M, and braking coefficient Dg) of the speed governor control circuit 833 and the particle system calculation circuit 837 are communicated from the CEMS 31 via the eighth control circuit 87.

[0195] (3-2-3-1) Speed ​​Regulator Control Circuit 833

[0196] Figure 15 This is an explanation Figure 14 The block diagram shown is of the structure of the speed controller control circuit 833.

[0197] like Figure 15 As shown, the speed controller control circuit 833 has a multiplier 91, a single-delay system model 92, and a limiting circuit 93.

[0198] Multiplier 91 multiplies the output of subtractor 832 with the proportional gain (-1 / Kgd) output from the eighth control circuit 87. The output of multiplier 91 is input to the primary delay system model 92. In Embodiment 1, the primary delay system model 92 adopts the standard model of a primary delay system (1 / (1+s×Tg)) proposed by the Institute of Electrical Engineers of Japan. Limiting circuit 93 performs limiting processing on the output of primary delay system model 92.

[0199] (3-2-3-2) Operational Circuit of Particle System 837

[0200] Figure 16 This is an explanation Figure 14 The block diagram shown is of the structure of the particle system operational circuit 837.

[0201] like Figure 16 As shown, the particle system operation circuit 837 includes a subtractor 101, an integrator 102, a multiplier 103, a divider 104, an adder 105, and a phase calculation circuit 106.

[0202] Subtractor 101 calculates the deviation between the output of subtractor 836 and the output of multiplier 103. The output of subtractor 101 is input to integrator 102.

[0203] Integrator 102 generates the output of subtractor 101 by dividing the output by the inertia constant M and then integrating it. Figure 45The target angular velocity of the generator rotor (2 x π x target frequency (e.g., 60 Hz)) is shown as a difference value Δω of the angular velocity of the generator rotor. The output of the integrator 102 is input to the multiplier 103.

[0204] The multiplier 103 multiplies the output of the integrator 102 by the braking coefficient Dg input from the eighth control circuit 87.

[0205] The mass system operation circuit 837 is configured to simulate the braking force possessed by the synchronous generator by control of the second DC / AC converter 408, in accordance with the deviation of the output of the subtracter 836 and the output of the multiplier 103.

[0206] The divider 104 converts the difference value Δω of the output of the integrator 102 into a difference value Δf of the frequency by dividing by 2 x π. The adder 105 converts the difference value Δf of the frequency into the frequency of the generator rotor (rotational frequency) by adding the target frequency (60 Hz) to the difference value Δf of the frequency. The output of the adder 105 is input to the phase calculation circuit 106. The phase calculation circuit 106 calculates the phase of the generator rotor.

[0207] Next, the transfer function of the swing equation of the mass system operation circuit 837 will be described. The transfer function of the swing equation is shown in the following equation (3) and can be expressed using the proportional gain (1 / Dg) and the time constant (M / Dg) of the first order delay system.

[0208] (1 / M x s) / {1 + Dg / M x (1 / s)}

[0209] = (1 / Dg) x [1 / {1 + (M / Dg) x s}... (3)

[0210] Further, the governor time constant Tg in the virtual synchronous generator control and the time constant M / Dg of the mass system operation circuit are determined in accordance with the response speed required of the system.

[0211] (Action outline of the distributed power source management device)

[0212] Next, an outline of the action of the distributed power source management device according to Embodiment 1 will be described.

[0213] Figure 17 is a graph showing the area covered by the virtual synchronous generator control installed in the power conversion device 41. Figure 17 The horizontal axis of indicates the response time and the vertical axis indicates the demand fluctuation amplitude.

[0214] As Figure 17As shown, the virtual synchronous generator control mounted to the stationary inverter covers slight variations and short-period variations of several tens of milliseconds to several minutes. With respect to variations of several minutes or more, it is possible to cope with them by load frequency control (LFC) or economic load dispatch control (EDC). Therefore, in Embodiment 1, the response performance of the virtual synchronous generator control is set to 1 second or less and is described.

[0215] In the following description, a model composed of a storage battery 40, a power conversion device 41, an impedance 29 of a power distribution system, and a load 600 connected to the power distribution system 24 shown in FIG. 1 is used. In order to simplify the description, the inverter capacity of the power conversion device 41 is set to 4 kW, and the capacity of the load 600 is set to a maximum of 4 kW. Figure 2

[0216] Figure 18 is a graph for explaining the virtual synchronous generator control related to Embodiment 1 mounted to the power conversion device 41. In Figure 18 , one example of the relationship between the speed adjustment rate Kgd and the system frequency when the consumption power of the load 600 is changed without changing the power target value is shown. Figure 18 In Figure 2 , the system frequency in each speed adjustment rate Kgd in a stable state when the load 600 is changed from 2 kW to 4 kW from a state where the power target value is notified from the CEMS 31 as 2 kW is shown. Further, the governor time constant Tg, the inertia constant M, and the braking coefficient Dg are each fixed to a constant value.

[0217] In the example of Figure 18 , the system frequency decreases as the value of Kgd becomes larger before Kgd becomes 0.343. On the other hand, it is confirmed that the system frequency converges when Kgd exceeds 0.343.

[0218] Figure 19 is a graph for explaining the virtual synchronous generator control related to Embodiment 1 mounted to the power conversion device 41. In Figure 19 , one example of the relationship between the braking coefficient Dg and the system frequency when the load is abruptly changed is shown. Figure 19 In Figure 2 , the system frequency in each braking coefficient Dg when the load is changed from 2 kW to 4 kW from a state where the power target value is notified from the CEMS 31 as 2 kW is shown. Further, the governor time constant Tg, the inertia constant M, and the speed adjustment rate Kgd (= 0.343) are each fixed to a constant value. In Figure 19 , it is confirmed that the decrease in the system frequency becomes larger as the braking coefficient Dg becomes smaller.

[0219] ​Generally, the limit value (upper limit value and lower limit value) of the system frequency is the reference frequency (hereinafter also referred to as Fref) ± 1 to 2%. Thus, in the case where the reference frequency Fref is 60 Hz, the upper limit value of the system frequency is 61.2 to 60.6 Hz, and the lower limit value of the system frequency is 59.4 to 58.8 Hz. Thus, it is necessary to set the speed adjustment rate Kgd of the governor control and the braking coefficient Dg in such a manner that the system frequency converges to the frequency range determined by the above limit values.

[0220] Next, the ΔP / ΔF characteristic will be described.

[0221] Figure 20 is a graph showing one example of the ΔP / ΔF characteristic. Figure 20 The horizontal axis of is the difference in power ΔP, which is the deviation of the output power of the power conversion device 41 from the power target value. With respect to the difference in power ΔP, a case where the output power of the power conversion device 41 is greater than the power target value is taken as positive.

[0222] Figure 20 The vertical axis of is the difference in frequency ΔF, which is the deviation of the frequency of the alternating voltage output from the power conversion device 41 from the reference frequency Fref (for example, 60 Hz) of the alternating current system. With respect to the difference in frequency ΔF, a case where the frequency of the alternating voltage output from the power conversion device 41 is higher than the reference frequency Fref is taken as positive. ΔFmax is the maximum value of the difference in frequency ΔF.

[0223] In the virtual synchronous generator control circuit 83 ( Figure 11 ) related to Embodiment 1, Figure 20 The ΔP / ΔF characteristic shown in is determined by the capacity of the static inverter (second DC / AC converter 408), the speed adjustment rate Kgd, and the braking coefficient Dg. Further, in Figure 20 , the power target value is set to half the capacity of the static inverter (second DC / AC converter 408) without taking the charge of the storage battery 40 into consideration. Figure 20 shows a case where the system frequency at which the consumption power of the load 600 becomes the same as the capacity of the static inverter (second DC / AC converter 408) in Figure 2 is set as the upper limit value (Fref + ΔFmax), and the system frequency at which the consumption power of the load 600 becomes zero is set as the lower limit value (Fref - ΔFmax).

[0224] In Embodiment 1, the Figure 20The illustrated ΔP / ΔF characteristic is referred to as a "reference ΔP / ΔF characteristic". As described above, the reference ΔP / ΔF characteristic is a ΔP / ΔF characteristic under the condition that, in the discharge mode of the storage battery 40, half of the capacity of the static inverter is set as the electric power target value, the system frequency becomes the upper limit value (Fref+ΔFmax) in the case where the output of the static inverter coincides with the capacity, and the system frequency becomes the lower limit value (Fref-ΔFmax) in the case where the output of the static inverter is zero. Further, details of the discharge mode are described later.

[0225] Figure 21 is a graph showing a response waveform of the frequency of the alternating voltage output from the static inverter at the time of a sudden change in load in the virtual synchronous generator control mounted on the power conversion device 41 according to Embodiment 1.

[0226] As explained in Figure 17 , the virtual synchronous generator control mounted on the static inverter covers slight vibrations and short-period fluctuations of several tens of milliseconds to several minutes. Therefore, in the virtual synchronous generator control, a response performance of 1 second or less is required. Generally, the response performance improves when the time constant is reduced, but vibrations occur in the response waveform. In addition, in the case where a plurality of distributed power sources act cooperatively, there can be a problem that unnecessary circulating currents and the like occur. Therefore, in Embodiment 1, as shown in Figure 21 , the time constants in the governor control circuit 833 Figure 15 and the mass system operation circuit 837 Figure 16 are determined in such a manner that the system frequency converges in 1 second.

[0227] (Conventional Virtual Synchronous Generator Control and Problem Points Thereof)

[0228] Next, a problem point in the case where two power conversion devices 41 in which the conventional virtual synchronous generator control is mounted are arranged to the power distribution system 24 is described.

[0229] Figure 22 is a graph showing a response waveform of the effective value of the alternating electric power output from the static inverter of each of the two power conversion devices 41 in which the conventional virtual synchronous generator control is mounted. Figure 22 The illustrated response waveform indicates a waveform of the effective value of the alternating electric power output from each static inverter at the time of a sudden change in load in the case where the two power conversion devices 41 are used to constitute independent systems.

[0230] In Figure 22In the example, the inverter capacity of each power conversion device 41 is set to 4 kW, and the consumption power of the load is set to 3.3 kW. The power target value of the first battery (indicated as "BAT1" in the drawing) corresponding to the first power conversion device 41 is set to 2.2 kW, and the power target value of the second battery (indicated as "BAT2" in the drawing) corresponding to the second power conversion device 41 is set to 1.1 kW, and the first and second power conversion devices 41 are controlled. It is assumed that the consumption power of the load is drastically changed to about half (1.65 kW) around 5 seconds in this state.

[0231] As shown in FIG. 6A, before the load is drastically changed, power around the power target value (2.2 kW) is output from the first power conversion device 41, and power around the power target value (1.1 kW) is output from the second power conversion device 41, and the power ratio of the two is 2: 1. Figure 22

[0232] On the other hand, after the load is drastically changed, the output power of the first power conversion device 41 becomes 1.35 kW, and the output power of the second power conversion device 41 becomes 0.3 kW, and the power ratio of the two is 9: 2. It is known that, after the load is drastically changed, power is output from the two power conversion devices 41 in a ratio (9: 2) different from the assumed power ratio distribution ratio (2: 1).

[0233] Figure 23 FIG. 6B shows the response waveform of the frequency of the alternating voltage output from each static inverter when the two power conversion devices 41 provided with the conventional virtual synchronous generator control are operated under the above conditions. As shown in FIG. 6B, with respect to the frequency of the alternating voltage, it is known that, even after the load is drastically changed, the virtual synchronous generator control converges to approximately the same frequency. Figure 23

[0234] Next, using FIGS. 7A and 7B, the reason for the change in the power ratio distribution ratio when the load is drastically changed will be described. Figure 24 Figure 25 FIG. 7A is a graph showing one example of the ΔP / ΔF characteristic of the first power conversion device 41 provided with the conventional virtual synchronous generator control.

[0235] FIG. 7B is a graph showing one example of the ΔP / ΔF characteristic of the second power conversion device 41 provided with the conventional virtual synchronous generator control. Figure 24 Figure 25 In the conventional virtual synchronous generator control, the ΔP / ΔF characteristic is not switched in accordance with the power target value and the capacity of the static inverter. In

[0236] Figure 24 Figure 25 ​​​​​In the example of FIG. 6, the capacities of the static inverters of the two power conversion devices 41 are the same (4 kW), so the same ΔP / ΔF characteristics are provided.

[0237] In the case of a rapid change in the load as shown in FIG. 7, in the virtual synchronous generator control installed in each power conversion device 41, the two power conversion devices 41 are caused to act in such a way as to share excess or insufficient power. At this time, as shown in FIG. 8, the two power conversion devices 41 are controlled in such a way that the frequencies of the alternating voltages output from the static inverters become equal to each other. Figure 22 Figure 23

[0238] On the other hand, the difference power ΔP of the power output from each power conversion device 41 and the power target value is determined by the ΔP / ΔF characteristics shown in FIG. 5 and FIG. 6. Therefore, in the case where the ΔP / ΔF characteristics of the two power conversion devices 41 are the same, the difference frequency ΔF is the same, so the difference power ΔP also becomes the same value. As a result, as shown in FIG. 8, after the load rapidly changes, the two power conversion devices 41 output power in different proportional distribution ratios from the proportional distribution ratio assumed. Figure 24 Figure 25 Figure 22

[0239] (Virtual synchronous generator control)

[0240] Figure 26 is a graph showing one example of the ΔP / ΔF characteristics of the second power conversion device 41 to which the virtual synchronous generator control according to Embodiment 1 is installed. The solid line in the graph indicates the ΔP / ΔF characteristics of the second power conversion device 41, and the dashed line indicates the ΔP / ΔF characteristics of the first power conversion device 41. Figure 24

[0241] As shown in FIG. 10, in the case where the power target value of the second power conversion device 41 (1.1 kW) is half the power target value of the first power conversion device 41 (2.2 kW) (i.e., the power proportional distribution ratio is 2: 1), as shown in FIG. 11, the ΔP / ΔF characteristics of the second power conversion device 41 are determined in such a way that the ratio of the difference power ΔP of the first power conversion device 41 (ΔP1 in the graph) and the difference power ΔP of the second power conversion device 41 (ΔP2 in the graph) at the same difference frequency ΔF becomes equal to the ratio of the power target values (2: 1). Figure 22 Figure 26 As shown in FIG. 12, in the case where the power target value of the second power conversion device 41 (1.1 kW) is half the power target value of the first power conversion device 41 (2.2 kW) (i.e., the power proportional distribution ratio is 2: 1), as shown in FIG. 13, the ΔP / ΔF characteristics of the second power conversion device 41 are determined in such a way that the ratio of the difference power ΔP of the first power conversion device 41 (ΔP1 in the graph) and the difference power ΔP of the second power conversion device 41 (ΔP2 in the graph) at the same difference frequency ΔF becomes equal to the ratio of the power target values (2: 1).

[0242] As shown in FIG. 14, in the case where the power target value of the second power conversion device 41 (1.1 kW) is half the power target value of the first power conversion device 41 (2.2 kW) (i.e., the power proportional distribution ratio is 2: 1), as shown in FIG. 15, the ΔP / ΔF characteristics of the second power conversion device 41 are determined in such a way that the ratio of the difference power ΔP of the first power conversion device 41 (ΔP1 in the graph) and the difference power ΔP of the second power conversion device 41 (ΔP2 in the graph) at the same difference frequency ΔF becomes equal to the ratio of the power target values (2: 1). Figure 26 ​​​​​​​The ΔP / ΔF characteristics of the two power conversion devices 41 are determined so that the ratio of the electric power shared by each power conversion device 41 becomes equal to the ratio (2:1) of the electric power target value notified from the CEMS 31 even in the case where the load changes.

[0243] (Method of creating ΔP / ΔF characteristics)

[0244] Next, a method of creating the ΔP / ΔF characteristics of each power conversion device 41 in the CEMS 31 will be described.

[0245] In Embodiment 1, in the case where the ΔP / ΔF characteristics of each power conversion device 41 are created, the CEMS 31 first creates a reference ΔP / ΔF characteristic for each power conversion device 41. In the following description, the method of creating the reference ΔP / ΔF characteristics will be described with limitation to discharging of the storage battery 40.

[0246] In the operation modes of the storage battery 40, there are a discharging mode in which discharging of the storage battery 40 is performed, a charging mode in which charging of the storage battery 40 is performed, and a charge-discharge mode in which charge-discharge of the storage battery 40 is performed. In the case where the storage battery 40 is caused to operate in the discharging mode or the charging mode, the reference ΔP / ΔF characteristics are created in such a manner that the differential electric power ΔP corresponding to the limit value ΔFmax of the differential frequency ΔF becomes half of the capacity of the static inverter.

[0247] On the other hand, in the case where the storage battery 40 is caused to operate in the charge-discharge mode (particularly, in the case where the electric power target value becomes around zero), the reference ΔP / ΔF characteristics are created in such a manner that the differential electric power ΔP corresponding to ΔFmax becomes equal to the capacity of the static inverter.

[0248] Further, the CEMS 31 needs to create the reference ΔP / ΔF characteristics of a plurality of power conversion devices 41 to be managed in the same strategy. Therefore, the CEMS 31 creates the reference ΔP / ΔF characteristics in the first power conversion device 41 with consideration of the charge-discharge mode, whereas the CEMS 31 creates the reference ΔP / ΔF characteristics in the second power conversion device 41 without consideration of the charging mode or the discharging mode.

[0249] Figure 27 is a graph showing one example of the reference ΔP / ΔF characteristics in the power conversion device 41 to which the virtual synchronous generator control is installed according to Embodiment 1.

[0250] In Embodiment 1, the reference ΔP / ΔF characteristics are created on the basis of the information on the limit value (Fref±ΔFmax) of the system frequency and the information on the capacity of the static inverter notified from the DSO 21.

[0251] Specifically, considering only the discharge mode, the power target value Pref is set to half the capacity of the static inverter. The reference ΔP / ΔF characteristic is created by making the system frequency the lower limit (Fref-ΔFmax) when the power conversion device 41 outputs power equal to the capacity of the static inverter, and the system frequency the upper limit (Fref+ΔFmax) when the output of the static inverter becomes zero.

[0252] Furthermore, considering only the charging mode, the same effect can be achieved by treating the charging power as a negative value, so that the system frequency becomes the lower limit (Fref-ΔFmax) when the charging power becomes zero, and the system frequency becomes the upper limit (Fref+ΔFmax) when the charging power becomes equal to the capacity of the static inverter.

[0253] Furthermore, considering the charging and discharging modes, the same effect can be achieved by setting the power target value Pref to zero, so that the system frequency is at the lower limit (Fref-ΔFmax) when discharging with the same power as the static inverter and at the upper limit (Fref+ΔFmax) when charging with the same power as the static inverter.

[0254] Next, use Figure 28 This indicates that it was used. Figure 27 The method for manufacturing the reference ΔP / ΔF characteristics and the ΔP / ΔF characteristics of each power conversion device 41.

[0255] Furthermore, in the following description, it is assumed that the static inverters of each power conversion device 41 have the same capacity. Figure 28 The middle section explains the use of Figure 27 The diagram illustrates a method for generating a ΔP / ΔF characteristic when the target power value differs from the target power value (half the capacity of the static inverter) in the baseline ΔP / ΔF characteristic. The dashed line in the diagram represents the baseline ΔP / ΔF characteristic (…). Figure 27 The solid line represents the ΔP / ΔF characteristic.

[0256] When the capacity of the static inverter is the same, in Embodiment 1, the slope of the ΔP / ΔF characteristic (the dashed line in the figure) is obtained by multiplying the slope of the reference ΔP / ΔF characteristic (0.5 times) by dividing half (0.5 times) of the static inverter capacity by the power target value Pref of the power conversion device 41. For example, when the power target value Pref is 0.25 times the capacity of the static inverter, the slope of the reference ΔP / ΔF characteristic is multiplied by 0.5 / 0.25 (=2) to obtain the slope of the ΔP / ΔF characteristic.

[0257] Next, a case where the capacities of the static inverters of the respective power conversion devices 41 are different will be described. In this case, the method of creating the reference ΔP / ΔF characteristics of the respective power conversion devices 41 is different from the above-described method of creating.

[0258] In the case where the capacities of the static inverters are different among the plurality of power conversion devices 41, the capacity of the static inverter that becomes the reference is determined in advance. For example, in the case where the capacities of the three static inverters are set to 10 kW, 8 kW, and 4 kW, the reference is set to 8 kW. Further, it is obvious that it is basically no problem which capacity is selected as the reference. Then, using the method of creating described in Figure 27 , the reference ΔP / ΔF characteristics of the static inverter having the reference capacity (8 kW) are created.

[0259] Next, using the reference ΔP / ΔF characteristics of the static inverter having the reference capacity (8 kW), the reference ΔP / ΔF characteristics of the static inverter having the capacity of 4 kW are created. Figure 29 is a graph for illustrating the method of creating the reference ΔP / ΔF characteristics of the static inverter having the capacity of 4 kW. The dashed line in the graph indicates the reference ΔP / ΔF characteristics of the static inverter having the reference capacity (8 kW) (reference ΔP / ΔF characteristics (8 kW)), Figure 27 , and the solid line indicates the reference ΔP / ΔF characteristics of the static inverter having the capacity of 4 kW.

[0260] As shown in Figure 29 , the slope of the reference ΔP / ΔF characteristics is found by multiplying the slope of the reference ΔP / ΔF characteristics for the reference capacity (8 kW) by the value obtained by dividing the reference capacity (8 kW this time) by the capacity of the own static inverter (4 kW this time). Specifically, the slope of the reference ΔP / ΔF characteristics of the static inverter having the capacity of 4 kW is calculated by multiplying the slope of the reference ΔP / ΔF characteristics of the static inverter having the reference capacity (8 kW) by 8 / 4 (= 2). Likewise, the slope of the straight line of the reference ΔP / ΔF characteristics of the static inverter having the capacity of 10 kW is calculated by multiplying the slope of the reference ΔP / ΔF characteristics of the static inverter having the reference capacity (8 kW) by 8 / 10 (= 0.8).

[0261] Figure 30 is a graph showing one example of the reference ΔP / ΔF characteristics and the ΔP / ΔF characteristics of two power conversion devices 41 whose capacities of the static inverters are different. In Figure 30In this case, the dashed line L1 indicates a reference ΔP / ΔF characteristic of the first power conversion device 41, and the solid line L2 indicates a ΔP / ΔF characteristic of the first power conversion device 41. The dashed line L3 indicates a reference ΔP / ΔF characteristic of the second power conversion device 41, and the solid line L4 indicates a ΔP / ΔF characteristic of the second power conversion device 41.

[0262] In Figure 30 the example, in the first power conversion device 41, the capacity of the static inverter is 8 kW, and the power target value is 6 kW. In the second power conversion device 41, the capacity of the static inverter is 4 kW, and the power target value is 1 kW.

[0263] Figure 31 is a graph showing the waveforms of the effective values of the alternating-current power output from the Figure 30 two power conversion devices 41 shown in Figure 31 the example, in the first power conversion device 41, the capacity of the static inverter is 8 kW, and the power target value is 2 kW. In the second power conversion device 41, the capacity of the static inverter is 4 kW, and the power target value is 1 kW.

[0264] Figure 31 The waveforms are waveforms in which the first and second power conversion devices 41 are caused to operate using the control parameters (Tg, Kgd, M, and Dg) generated by the virtual synchronous generator control circuit 83 in the case where the power target values of the two power conversion devices 41 are 2 kW and 1 kW, based on the reference ΔP / ΔF characteristics (solid lines L1 and L3 in the graph) of the two power conversion devices 41 shown in Figure 30

[0265] In Figure 31 , waveforms of the effective values of the alternating-current power output from each power conversion device 41 are shown in the case where the load is abruptly changed from 3 kW to 5.25 kW. As Figure 31 indicated, it is seen that the power ratio distribution ratio of the first and second power conversion devices 41 becomes 2:1 both before the abrupt change in the load and after the abrupt change in the load, and operates in accordance with the assumption.

[0266] As explained above, in the case where a plurality of power conversion devices 41 having static inverters installed with virtual synchronous generator control are connected to the power distribution system 24, for each power conversion device 41, a ΔP / ΔF characteristic is made in accordance with the capacity of the static inverter and the power target value. Also, for each power conversion device 41, the control parameters of the virtual synchronous generator control circuit 83 (Tg, Kgd, M, and Dg) are generated using the ΔP / ΔF characteristic. Figure 11

[0267] ​​By being configured as such, even in the case where the consumed power of the load 600 or the generated power of the mega solar power plant 26 changes drastically, the ratio of the power output from each power conversion device 41 can be made equal to the ratio of the power target value notified from the CEMS 31. Thus, it is possible to prevent the ratio of the discharge power of the battery 40, which sets the discharge power to be small due to a small SOC, for example, from becoming large in the entire discharge power.

[0268] Further, in Embodiment 1, as the method of creating the ΔP / ΔF characteristic, the method of creating the reference ΔP / ΔF characteristic of each power conversion device 41 and creating the ΔP / ΔF characteristic according to the power target value using the created reference ΔP / ΔF characteristic is described, but is not limited thereto. For example, it can be configured to directly generate the control parameters (Tg, Kgd, M, Dg) of the virtual synchronous generator control circuit 83 according to the capacity of the static inverter, the power target value, and the SOC information of the battery 40.

[0269] (Action of the distributed power source management device)

[0270] Next, the action of the distributed power source management device according to Embodiment 1 will be described in detail using Figures 1 to 41

[0271] First, the power distribution system 24 to which the distributed power source management device according to Embodiment 1 is applied will be described with reference to Figure 1

[0272] In Embodiment 1, the power distribution system 24 has a plurality of SVRs 23 connected in series between the substation 20 and the power conversion device 27 (or the power conversion device 41a or the town 100a) in order to control the system voltage supplied from the substation 20 within a predetermined voltage range.

[0273] The power conversion device 27 acts as a current source. The power conversion device 41a is provided in the vicinity of the power conversion device 27. In Embodiment 1, the power conversion device 41a acts as a voltage source. The power conversion device 41a can also smooth the generated power of the mega solar power plant 26 by performing virtual synchronous generator control.

[0274] As the loads, there are the towns 100a to 100d, the factory 110, the building 112, and the apartment 113. The loads are supplied with power supplied from the substation 20, the generated power of the mega solar power plant 26, and the discharge power of the battery 40. The synchronous generator 30a for emergency is disposed in the factory 110, and the synchronous generator 30b for emergency is disposed in the building 112.

[0275] ​​Here, the operation of the distributed power source management device in the power distribution system 24 that receives the electric power supplied from the substation 20, the electric power generated by the mega solar power plant 26, and the discharge electric power of the storage battery 40 will be described.

[0276] Figure 32 is a time chart for explaining the general operation of the distributed power source management device centered on the CEMS 31. Figure 1

[0277] As shown in Figure 32 , the process at the time of stabilization includes a process (hereinafter also referred to as "first process") that is implemented in a period of 30 minutes and a process (hereinafter also referred to as "second process") that is implemented in a period of 5 minutes.

[0278] After the start of the first process (30-minute-period process), the DSO 21 requests the CEMS 31 to output the collected measurement data via the communication line 25. The CEMS 31 transmits the measurement data including the consumed electric power amount of each demander, the generated electric power amount of the mega solar power plant 26, and the charge / discharge electric power amount and SOC of the storage battery 40 collected during the most recent 30 minutes to the DSO 21 upon receiving the request from the DSO 21.

[0279] Upon receiving the measurement data, the DSO 21 makes an operation plan of the power distribution system 24 based on the measurement data and notifies the CEMS 31 of the made operation plan. The operation plan of the power distribution system 24 includes an electric power supply plan from the substation 20 to the power distribution system 24, which is necessary for making an operation plan (charge / discharge plan) of the storage battery 40. The DSO 21 makes the 30-minute-period electric power supply plan in an amount corresponding to 24 hours. The 30-minute-period electric power supply plan indicates the total electric power amount supplied from the substation 20 to the power distribution system 24 during 30 minutes.

[0280] The CEMS 31, upon receiving the operation plan (electric power supply plan) from the DSO 21, requests the power conversion device 41 to transmit the measurement data. The measurement data includes the charge / discharge electric power amount and the SOC information of the storage battery 40 during the most recent 5 minutes. The power conversion device 41, upon receiving the request from the CEMS 31, notifies the CEMS 31 of the measurement data.

[0281] The CEMS 31 receives the measurement data from all the power conversion devices 41a to 41c connected to the power distribution system 24. At this time, the CEMS 31 also collects the measurement data such as the consumed electric power amount of each demander during 30 minutes and the generated electric power amount of the mega solar power plant 26.

[0282] ​After the measurement data is collected, CEMS31 generates the operation plan and control parameters for battery 40. The operation plan for battery 40 is the charging and discharging plan for battery 40, including the target values ​​of the charging and discharging power of battery 40 (power target values). The method for generating the operation plan and control parameters for battery 40 will be described later.

[0283] After the operation plan and control parameters of the storage battery 40 are completed, the CEMS31 notifies each power conversion device 41 of the corresponding operation plan and control parameters of the storage battery 40, and ends the first process.

[0284] Next, CEMS31 performs a second processing step (5-minute cycle processing). CEMS31 collects measurement data from each power conversion device 41 every 5 minutes. Based on the collected measurement data, CEMS31 detects the deviation between the target power value and the actual charging / discharging power. If the deviation exceeds a predetermined threshold, CEMS31 recalculates the operating plan (target power value) for the battery 40 and notifies each power conversion device 41 of the recalculation result. The specific method for this recalculation will be described later.

[0285] (CEMS31's actions)

[0286] Next, use Figure 33 This will explain the detailed operation of CEMS31.

[0287] Figure 33 It is shown Figure 1 The flowchart shown is for the control processing of CEMS31. Figure 33 As shown, after processing begins, CEMS31 checks in step (hereinafter referred to as S)01 whether it has received an output request for measurement data from DSO21. If an output request is received ("Yes" in S01), CEMS31 collects measurement data from multiple power conversion devices 41 via S02. CEMS31 then notifies DSO21 of the measurement data stored in storage circuit 12 via communication circuit 11 via S03.

[0288] On the other hand, if no output request is received from DSO21 ("No" in S01) or if measurement data has been sent to DSO21 in S03, CEMS31 proceeds to S04 to confirm whether an operation plan (power supply plan) has been received from DSO21. If an operation plan has been received ("Yes" in S04), CEMS31 proceeds to S05 to create an operation plan (charge and discharge plan) for battery 40.

[0289] Figure 34 This illustrates the process of manufacturing the storage battery 40. Figure 33 the flowchart of S05).

[0290] As shown in FIG. 5, after the process is started, the CEMS 31 predicts the power generation amount of the mega solar power plant 26 by S051. Specifically, returning to FIG. 5, the management circuit 146 in the operation plan making circuit 14 is instructed by the control circuit 16 (S051) to make an operation plan. The management circuit 146 instructs the power generation power prediction circuit 142 via the storage battery operation plan making circuit 141 to predict the power generation power of the mega solar power plant 26 upon receiving the instruction from the control circuit 16. Figure 34 Figure 3 Figure 4 Upon receiving the operation plan from the DSO 21, the control circuit 16 (S052) instructs the management circuit 146 in the operation plan making circuit 14 to make an operation plan. The management circuit 146 instructs the consumption power prediction circuit 143 via the storage battery operation plan making circuit 141 to predict the consumption power of the demand side upon receiving the instruction from the control circuit 16. Figure 3 Figure 4

[0291] The power generation power prediction circuit 142, upon receiving the instruction from the management circuit 146, acquires a 24-hour amount of weather forecast from now to 24 hours later by accessing a weather forecast server configured on the Internet not shown. The power generation power prediction circuit 142 predicts a 24-hour amount of power generation amount from now to 24 hours later using the acquired 24-hour amount of weather forecast and data stored in a database (not shown) for power generation amount prediction managed by the power generation power prediction circuit 142. Further, the database for power generation amount prediction is constructed from actual data of power generation amount of the mega solar power plant 26 and weather actual data information collected in a period of 30 minutes. The description of the construction method of the database is omitted.

[0292] Upon predicting the power generation amount in S051, the CEMS 31 predicts the consumption power of the demand side by S052. Specifically, returning to FIG. 5, the management circuit 146, upon receiving the prediction result of the power generation amount of the mega solar power plant 26 from the power generation power prediction circuit 142, instructs the consumption power prediction circuit 143 via the storage battery operation plan making circuit 141 to predict the consumption power of the demand side. Figure 4

[0293] The consumption power prediction circuit 143, upon receiving the instruction from the management circuit 146, predicts a 24-hour amount of consumption power of the demand side from now to 24 hours later using data stored in a database (not shown) for consumption power prediction managed by the consumption power prediction circuit 143. Further, the database for consumption power prediction is constructed by processing the consumption power of the demand side collected in a period of 30 minutes in terms of date, time information, and weather information. The description of the construction method of the database is omitted.

[0294] ​​​​​After predicting the power consumption amount of the demand side in S052, the CEMS 31 makes a demand plan through S053. Specifically, returning to Figure 4 When the power consumption prediction circuit 143 receives the prediction result of the power consumption amount of the demand side, the storage battery operation plan making circuit 141 calculates the total value of the charge and discharge power amount of each of the storage batteries 40a to 40c every 30 minutes, based on the prediction result of the power generation amount of the mega solar power plant 26 predicted by the power generation prediction circuit 142, the prediction result of the power consumption amount of the demand side predicted by the power consumption prediction circuit 143, and the operation plan (power supply plan every 30 minutes) notified from the DSO 21.

[0295] After making the demand plan in S053, the CEMS 31 sets the charge and discharge power (power target value) of the storage batteries 40a to 40c through S054. Specifically, returning to Figure 3 and Figure 4 The storage battery operation plan making circuit 141 proportionally allocates the charge and discharge power of each of the storage batteries 40 every 30 minutes, based on the SOC information of the storage batteries 40a to 40c and the storage battery capacities collected to the storage circuit 12 via the communication circuit 11.

[0296] In Embodiment 1, when making the operation plan of the storage batteries 40 for 24 hours, the CEMS 31 sets the charge and discharge power of each of the storage batteries 40 in such a manner that the SOCs of the storage batteries 40a to 40c become zero at the same time or that the storage batteries 40a to 40c all become fully charged after 24 hours.

[0297] This is because of the following reasons. For example, assume a case where the power generation of the mega solar power plant 26 decreases from 10 MW to 4 MW around 5 minutes due to clouds passing over the mega solar power plant 26. Further, the capacities of the static inverters of the power conversion devices 41a to 41c are set to 8 MW, 4 MW, and 2 MW, respectively.

[0298] Here, the operation plan of the storage batteries is notified to the power conversion devices 41b and 41c in such a manner that 1 MW and 0.5 MW are discharged from the remaining storage batteries 40b and 40c, respectively, because the SOC of the storage battery 40a is initially zero and the discharge is stopped. In a case where the power generation of the mega solar power plant 26 decreases by 6 MW due to a sharp change in the amount of sunlight, regarding the discharge power of the storage batteries 40b and 40c, it is possible to add only 3 MW and 1.5 MW, respectively, by the virtual synchronous generator control, so it is not possible to compensate for the shortage of 6 MW.

[0299] On the other hand, when batteries 40a to 40c are operating, they can discharge up to a maximum of 14MW (=8MW+4MW+2MW), thus expanding the range of power that can be compensated by virtual synchronous generator control. Therefore, when creating an operation plan (charge and discharge plan) for battery 40 in CEMS31, the operation plan needs to be created in a way that makes the SOC of batteries 40a to 40c approximately zero or fully charged at the same time.

[0300] After setting the charging and discharging power (target power value) for batteries 40a-40c in S054, CEMS31 checks in S055 whether control parameters for virtual synchronous generator control have been generated for all batteries 40a-40c. If the generation of control parameters for all batteries 40a-40c has not yet been completed (in S055, it is marked "No"), CEMS31 proceeds to S056 to generate the control parameters for virtual synchronous generator control.

[0301] Figure 35 This illustrates the process of generating control parameters for virtual synchronous generator control. Figure 34 The flowchart of S056). The control parameter generation circuit 13 within CEMS31 ( Figure 5 )implement Figure 35 The processing shown.

[0302] like Figure 35 As shown, after processing begins, control circuit 136 ( Figure 5 Collected via S0561 Figure 34 In S054, the battery operation plan generation circuit 141 generates the target power value of the battery 40 for the next 30 minutes, the capacity of the second DC / AC converter 408 (static inverter) within the power conversion device 41, and information related to the power distribution system 24. Furthermore, the information related to the power distribution system 24 includes the upper and lower limits of the system frequency, and the virtual synchronous generator control circuit 83 (… Figure 11 The upper limit of the system frequency is the reference frequency Fref (e.g., 60Hz) + ΔFmax, and the lower limit of the system frequency is Fref - ΔFmax.

[0303] After information collection is completed in S0561, the reference ΔP / ΔF characteristic calculation circuit 131 calculates the reference ΔP / ΔF characteristic for each power conversion device 41 in S0562. The reference ΔP / ΔF characteristic will be explained below.

[0304] In a case where the control parameters of the power conversion device 41 installed with the virtual synchronous generator control are generated, first, the reference ΔP / ΔF characteristic of the static inverter is calculated. Further, in Embodiment 1, the structure of generating the control parameters for the power conversion device 41 is explained, but the same method can be used to generate the control parameters also with respect to the structure where the virtual synchronous generator control is installed in the power conversion device where the output can be adjusted, such as the wind power generation device.

[0305] Specifically, as shown in FIG. 13, in the discharging mode of the storage battery 40, the reference ΔP / ΔF characteristic is determined in such a manner that half of the capacity of the static inverter is set as the power target value so that the frequency of the alternating voltage when the static inverter discharges the maximum power becomes equal to the lower limit frequency (ΔF = -ΔFmax) and the frequency of the alternating voltage when the discharging power of the static inverter is zero becomes equal to the upper limit frequency (ΔF = ΔFmax). Figure 27 Figure 27 Figure 27

[0306] On the other hand, in the charging mode of the storage battery 40, the reference ΔP / ΔF characteristic is determined in such a manner that half of the capacity of the static inverter is set as the power target value so that the frequency of the alternating voltage when the static inverter charges the maximum power becomes the upper limit frequency (ΔF = ΔFmax) and the frequency of the alternating voltage when the charging power of the static inverter is zero becomes equal to the lower limit frequency (ΔF = -ΔFmax).

[0307] Further, in the charge-discharge mode of the storage battery 40, the reference ΔP / ΔF characteristic is determined in such a manner that the power target value of the static inverter is set to zero so that the frequency of the alternating voltage when the static inverter discharges the maximum power becomes equal to the lower limit frequency (ΔF = -ΔFmax) and the frequency of the alternating voltage when the static inverter charges the maximum power becomes equal to the upper limit frequency (ΔF = ΔFmax).

[0308] Figure 36 is a flowchart showing the process (S0562) of generating the reference ΔP / ΔF characteristic. Figure 35

[0309] As shown in FIG. 14, after the start of the process, the reference ΔP / ΔF characteristic calculation circuit 131 (131a) collects the capacity information (Cinv) of the static inverter that becomes the object from the control circuit 136 by S05621. Figure 36 Figure 5

[0310] ​​​​​​When the capacity information of the static inverter is collected, the reference ΔP / ΔF characteristic calculation circuit 131 collects system information (ΔFmax) via S05622. Next, the reference ΔP / ΔF characteristic calculation circuit 131 uses the inverter capacity Cinv and ΔFmax to calculate the slope of the reference ΔP / ΔF characteristic via S05623.

[0311] Specifically, when the battery 40 is in charging or discharging mode, the reference ΔP / ΔF characteristic calculation circuit 131 sets the slope of the reference ΔP / ΔF characteristic to -ΔFmax / (Cinv×0.5). On the other hand, when the battery 40 is in charging or discharging mode, the slope of the reference ΔP / ΔF characteristic is set to -ΔFmax / Cinv.

[0312] Furthermore, regarding the reference ΔP / ΔF characteristics for using the discharge mode (or charging mode) and which of the charge / discharge modes, the battery operation planning circuit 141 ( Figure 4 According to Figure 34 The battery operation plan generation circuit 141 judges the result of determining the charging and discharging power of the battery 40 in the demand plan generated in S053. Specifically, if the absolute value of the determined charging and discharging power is less than a predetermined value, the battery operation plan generation circuit 141 adopts the charging and discharging mode. In addition, the adopted mode is applied to all power conversion devices 41 connected to the power distribution system 24.

[0313] Return to Figure 35 After calculating the baseline ΔP / ΔF characteristic in S0562, the ΔP / ΔF characteristic calculation circuit 132 is then used in S0563. Figure 5 Generate ΔP / ΔF characteristics. Specifically, return to Figure 5 The reference ΔP / ΔF characteristic calculation circuit 131 outputs the slope of the generated reference ΔP / ΔF characteristic to the control circuit 136 and the ΔP / ΔF characteristic calculation circuit 132.

[0314] The ΔP / ΔF characteristic calculation circuit 132 calculates the ΔP / ΔF characteristic based on the power target value provided by the control circuit 136. Figure 37 This illustrates the process for generating the ΔP / ΔF characteristics. Figure 35 The flowchart of S0563). Figure 37 As shown, after processing begins, the ΔP / ΔF characteristic calculation circuit 132 collects the power target value from the control circuit 136 via S05631. The ΔP / ΔF characteristic calculation circuit 132 then determines via S05632 whether the collected power target value does not exceed the static inverter capacity Cinv.

[0315] In a case where the magnitude of the power target value exceeds the static inverter capacity Cinv (NO in S05632), in S05633, the ΔP / ΔF characteristic calculation circuit 132 limits the power target value to the static inverter capacity Cinv by a limiter.

[0316] The ΔP / ΔF characteristic calculation circuit 132 calculates the slope of the ΔP / ΔF characteristic using the power target value by S05634. Specifically, in a case where the storage battery 40 is in the discharging mode or the charging mode, the slope of the ΔP / ΔF characteristic is set to the slope of the reference ΔP / ΔF characteristic × (Cinv × 0.5) / the power target value. On the other hand, in a case where the storage battery 40 is in the charging and discharging mode, the variation in the power generated by the mega solar power plant 26 or the like or the wind power generation is assumed to be absorbed (the power target value is zero), and the reference ΔP / ΔF characteristic, that is, the reference ΔP / ΔF characteristic calculated in S0562 of Figure 35

[0317] Returning to Figure 35 , after the ΔP / ΔF characteristic is generated by S0563, by S0564, the control circuit 136 generates the control parameter of the virtual synchronous generator control. The method of generating the control parameter will be described using Figure 5 and Figure 38 .

[0318] As shown in Figure 5 , the control circuit 136 instructs the control parameter generation circuit 133 to generate the control parameter.

[0319] Upon receiving the instruction to generate the control parameter, the control parameter generation circuit 133 generates the control parameter based on the slope of the ΔP / ΔF characteristic provided from the ΔP / ΔF characteristic calculation circuit 132, the system information (the reference frequency Fref, ΔFmax) input from the control circuit 136, the power target value Pref, and the inverter capacity Cinv. In Embodiment 1, a case where the virtual synchronous generator model 134 that simulates the operation of the virtual synchronous generator control circuit 83 is installed in the control parameter generation circuit 133 and the model is used to generate the control parameter will be described. Figure 3 Figure 11

[0320] Further, the method of generating the control parameter is not limited thereto, and for example, it can be configured to store the relationship between the speed adjustment rate Kgd and the system frequency shown in Figure 18 for each braking coefficient Dg as corresponding table data, and to generate the control parameter by referring to the table data. Figure 19 ​​​The relationship between the braking coefficient Dg and the system frequency is stored as corresponding tabular data for each speed adjustment rate Kgd. These tabular data are used to determine the appropriate speed adjustment rate Kgd and braking coefficient Dg.

[0321] In implementation 1, as a virtual synchronous generator model 134, a method is used... Figures 14 to 16 The block diagram shown is used to model the model, but it is not limited to this. For example, it can also be configured to generate a virtual synchronous generator control circuit 83 based on the transfer function of the governor control unit shown in equation (1) and the swing equation shown in equation (2). Figure 11 The transfer function is generated, and control parameters are generated based on the generated transfer function.

[0322] Figure 38 This illustrates the process of generating control parameters. Figure 35 The flowchart of S0564). Figure 38 As shown, after the generation of control parameters begins, the virtual synchronous generator model 134 ( Figure 5 By using S05641, the speed regulation rate Kgd and the braking coefficient Dg are set to predetermined initial values, thereby initializing the speed regulation rate Kgd and the braking coefficient Dg. In Implementation 1, it is assumed that the virtual synchronous generator model 134 only generates the speed regulation rate Kgd and the braking coefficient Dg that determine the ΔP / ΔF characteristics.

[0323] After initializing the speed regulation rate Kgd and braking coefficient Dg in S05641, the virtual synchronous generator model 134 enters S05642, using the speed regulation rate Kgd and braking coefficient Dg to calculate the slope of the ΔP / ΔF characteristic.

[0324] Virtual synchronous generator model 134, through S05643, compares the slope of the ΔP / ΔF characteristic calculated in S05642 with that calculated in S05642. Figure 35 S0563 ( Figure 37 The slope of the generated ΔP / ΔF characteristics. Specifically, the virtual synchronous generator model 134 confirms whether the deviation of the slopes of these two ΔP / ΔF characteristics falls within a predetermined allowable range.

[0325] If the slope deviation falls within the above-mentioned allowable range, the virtual synchronous generator model 134 determines that the slopes of the two ΔP / ΔF characteristics are consistent ("Yes" in S05643), and causes the process to proceed to S05649.

[0326] On the other hand, in a case where the deviation of the slope does not enter the above-mentioned allowable range, the virtual synchronous generator model 134 determines that the slopes of the two ΔP / ΔF characteristics are not consistent (NO in S05643). In this case, the virtual synchronous generator model 134 proceeds to S05644, and changes the braking coefficient Dg. In Embodiment 1, the virtual synchronous generator model 134 adds a predetermined value to the current braking coefficient Dg.

[0327] After changing the braking coefficient Dg in S05644, the virtual synchronous generator model 134 proceeds to S05645, and confirms whether the braking coefficient Dg enters a predetermined range decided in advance. If the braking coefficient Dg enters the predetermined range (YES in S05645), the virtual synchronous generator model 134 returns to S05642, and calculates the slope of the ΔP / ΔF characteristic using the changed braking coefficient Dg.

[0328] On the other hand, in a case where the braking coefficient Dg exceeds the predetermined range (NO in S05645), the virtual synchronous generator model 134 determines that a suitable characteristic cannot be obtained at the current speed adjustment rate Kgd, returns the braking coefficient Dg to the initial value through S05646, and changes the speed adjustment rate Kgd. Specifically, the virtual synchronous generator model 134 adds a predetermined value to the current speed adjustment rate Kgd (initial value).

[0329] After changing the speed adjustment rate Kgd in S05646, the virtual synchronous generator model 134 proceeds to S05647, and confirms whether the speed adjustment rate Kgd enters a predetermined range decided in advance. In a case where the speed adjustment rate Kgd departs from the predetermined range (NO in S05647), the virtual synchronous generator model 134 proceeds to S05648, sets that a suitable speed adjustment rate Kgd and a braking coefficient Dg are not obtained, sets the speed adjustment rate Kgd and the braking coefficient Dg to respective default values prepared in advance, and causes the processing to proceed to S05649.

[0330] On the other hand, in a case where the speed adjustment rate Kgd is within the predetermined range in S05647 (YES in S05647), the virtual synchronous generator model 134 returns to S05642, and calculates the slope of the ΔP / ΔF characteristic using the changed speed adjustment rate Kgd and the braking coefficient Dg. The virtual synchronous generator model 134 repeatedly executes the processing of S05642 to S05647 until it is determined YES in S05654 or it is determined NO in S05647.

[0331] After setting the speed regulation rate Kgd and the braking coefficient Dg, the control parameter generation circuit 133 calculates the inertia constant M via S05649. In Embodiment 1, the inertia constant M is calculated based on the response time required in the virtual synchronous generator control. Specifically, based on the speed governor control circuit 833 ( Figure 14 The governor time constant Tg and the particle system calculation circuit 837 obtained by the oscillation equation. Figure 14 The time constant M / Dg determines the response performance of the virtual synchronous generator control. In Implementation 1, the default value of the governor time constant Tg is used, and the governor time constant Tg is not generated, so only the time constant of the particle system operation circuit 837 is controlled. According to the above equation (3), the time constant of the particle system operation circuit 837 is obtained by M / Dg. Therefore, in Implementation 1, the inertia constant M is calculated by multiplying the time constant of the particle system operation circuit 837 determined by the default value by the braking coefficient Dg.

[0332] Return to Figure 34 After generating the control parameters for the virtual synchronous generator in S056, the circuit returns to S055, where the control parameter generation circuit 13 checks whether the calculation of control parameters for all power conversion devices 41 connected to the power distribution system 24 is complete. If the calculation of control parameters for all power conversion devices 41 is not yet complete (in S055, "No"), the control parameter generation circuit 13 proceeds to S056 to calculate the control parameters for the next power conversion device 41. On the other hand, if the calculation of control parameters for all power conversion devices 41 is complete (in S055, "Yes"), the control parameter generation circuit 13 ends the creation of the battery 40 operation plan.

[0333] In passing Figure 33 After the operation plan of battery 40 is completed by S05, the battery operation plan production circuit 141 ( Figure 4 The system notifies the management circuit 145 of the generated operation plan (power target value). Upon receiving the operation plan, the management circuit 145 stores the received operation plan in its memory and notifies the data generation circuit 15. Figure 3 The control parameter generation circuit 13 notifies the data transmission generation circuit 15 of the generated control parameters.

[0334] After obtaining the operating plan (power target value) and control parameters of the battery 40, the data generation circuit 15 processes them into a transmission format and outputs them to the communication circuit 11. Figure 3 When the communication circuit 11 receives the transmission data from the transmission data generation circuit 15, it transmits the transmission data to the corresponding power conversion device 41 via the communication line 25.

[0335] exist Figure 33 In S10, after the operation plan and control parameters for all power conversion devices 41 are sent, S11 checks whether to stop CEMS31. If CEMS31 is stopped ("Yes" in S11), the process ends. On the other hand, if CEMS31 is not stopped ("No" in S11), the process returns to S01.

[0336] In contrast, Figure 33 If no operation plan (power supply plan) is received from DSO21 in S04 ("No" in S04), CEMS31 proceeds to S06 to check whether the collection time for various measurement data has arrived. In Embodiment 1, as described above, CEMS31 collects measurement data in 5-minute cycles. If the collection time for measurement data has not arrived ("No" in S06), the process returns to S01. On the other hand, if the collection time for measurement data has arrived ("Yes" in S06), CEMS31 collects measurement data in S07. In Embodiment 1, CEMS31 collects the charging and discharging power of the battery 40, the current charging and discharging power, and SOC information from the power conversion devices 41a to 41c for 5 minutes as measurement data.

[0337] After collecting measurement data in S07, CEMS31 confirms in S08 whether the operation plan of the battery 40 needs to be revised. In S07, CEMS31 compares the current charge / discharge power with the operation plan (power target value) for each of the multiple batteries 40. Specifically, CEMS31 confirms whether the power difference between the current charge / discharge power and the power target value exceeds a predetermined range, and whether the SOC of the battery 40 exceeds a predetermined allowable range. If the power difference in any of the multiple batteries 40 exceeds the predetermined range, and / or the SOC exceeds the allowable range, CEMS31 re-evaluates the operation plans of all batteries 40. Furthermore, the operation plans of batteries 40 whose power difference exceeds the predetermined range and / or whose SOC exceeds the allowable range can also be re-evaluated.

[0338] CEMS31 checks whether the operation plan of the battery 40 needs to be modified according to the above-mentioned procedure. If it determines that the operation plan of the battery 40 does not need to be modified ("No" in S08), it returns to S01 and continues processing. On the other hand, if it determines that the operation plan of the battery 40 needs to be modified ("Yes" in S08), CEMS31 proceeds to S09 and modifies all the operation plans of the battery 40.

[0339] Figure 39 This demonstrates the process of revising the operating plan of the storage battery 40. Figure 33The flowchart of S09). The circuit 14 (within CEMS31) is used to create the operation plan. Figure 4 )implement Figure 39 The processing shown.

[0340] like Figure 39 As shown, after processing begins, the management circuit 146 ( Figure 4 )Through S091, for the battery operation plan correction circuit 144 ( Figure 4 The system instructs the correction of the operating plan and transmits the charging and discharging power and SOC information collected from each power conversion device 41. In S092, the management circuit 146 also outputs the data stored in the management circuit 145 to the battery operating plan correction circuit 144. Figure 4 The operating plan (power target value) of the battery 40 and the capacity of the static inverter of the power conversion device 41 stored in the storage circuit 12.

[0341] The battery operation plan correction circuit 144 re-evaluates the operation plan of the battery 40 based on information provided from the management circuit 146. For example, consider the following situation: because any one of the predicted values ​​of the power generation of the megawatt-class solar power generation device 26 and the predicted values ​​of the power consumption of each demander deviates from the actual data value, the output power of the power conversion device 41 becomes twice the power target value.

[0342] In such a situation, the system frequency is assumed to drop to near the lower limit (Fref - ΔFmax). If further power shortage occurs, the system frequency becomes the lower limit, and a situation may arise where the power conversion device 41 is unable to supply more power.

[0343] Therefore, in Embodiment 1, when the ratio of the target power value to the charge / discharge power is not within a predetermined range, the battery operation plan correction circuit 144 corrects the operation plan (target power value) of the battery 40 based on measurement data collected in 5-minute cycles. Specifically, the battery operation plan correction circuit 144 corrects the operation plan of the battery 40 based on the current charge / discharge power and SOC information.

[0344] The reason for using SOC in the revision of the battery 40's operation plan is that, when using a lithium-ion battery as the battery 40, the battery 40 sometimes fails or deteriorates rapidly due to overcharging or over-discharging. Therefore, in normal battery control, when the SOC exceeds, for example, 90%, the battery charging mode is switched from constant current charging mode to constant voltage charging mode. In constant voltage charging mode, it is not possible to set a large charging power, so the power target value needs to be reduced in the virtual synchronous generator control. Similarly, when over-discharging occurs, the battery 40 deteriorates, so the discharge power needs to be reduced when the SOC falls below, for example, 5%. Therefore, SOC is used in the creation and revision of the battery 40's operation plan.

[0345] Furthermore, when using lead-acid batteries as storage battery 40, although they are resistant to overcharging, there is a tendency for degradation to occur due to over-discharge. Therefore, in the case of lead-acid batteries, it is necessary to reduce the discharge power, for example, when the State of Charge (SOC) is below 20%. As described above, in order to suppress the degradation of the battery used, the SOC is used to adjust the power target value.

[0346] Specifically, the battery operation plan correction circuit 144 creates an operation plan for the battery 40 based on the current charge / discharge power. However, during charging when the State of Charge (SOC) is near its upper limit and during discharging when the SOC is near its lower limit, the battery operation plan is created based on the current charge / discharge power and the SOC. Specifically, the target charging power is reduced when the SOC is close to its upper limit, and the target discharging power is reduced when the SOC is close to its lower limit.

[0347] After modifying the operating plan (power target value) of battery 40 in S093, the parameter generation circuit 13 is controlled via S094. Figure 3 The system confirms whether the calculation of all control parameters for the batteries 40 is complete. If the calculation of all control parameters for the batteries 40 is complete ("Yes" in S094), the battery operation plan correction circuit 144 ends the correction process of the battery operation plan. On the other hand, if the correction of the operation plan for all batteries 40 is not yet complete ("No" in S094), the control parameter generation circuit 13 generates control parameters for the virtual synchronous generator control via S095. Furthermore, the method for generating the control parameters for the virtual synchronous generator control is the same as that used in the battery operation plan creation process described above. Figure 34 S056 and Figure 35 The generation method used in () is the same, so the explanation is omitted.

[0348] After generating the control parameters in S095, the circuit returns to S094, where the control parameter generation circuit 13 confirms whether the calculation of control parameters for all power conversion devices 41 has been completed. If the calculation of control parameters for all power conversion devices 41 has not been completed (in S094, "No"), the control parameter generation circuit 13 generates the control parameters for the next power conversion device 41 in S095.

[0349] On the other hand, after all the control parameters of the power conversion device 41 have been calculated ("Yes" in S094), the battery operation plan correction circuit 144 ends the correction process of the operation plan of the battery 40.

[0350] Return to Figure 33 After the operation plan of the storage battery 40 is corrected in S09, the storage battery operation plan creation circuit 141 notifies the management circuit 145 of the corrected operation plan (power target value) in the same way as when the operation plan is created.

[0351] After obtaining the operation plan of the battery 40 from the battery operation plan generation circuit 141, the management circuit 145 stores the obtained operation plan in a memory (not shown) and notifies the data transmission generation circuit 15. Similarly, the control parameter generation circuit 13 notifies the data transmission generation circuit 15 of the operation plan and control parameters of the battery 40.

[0352] When the data generation circuit 15 receives the operation plan and control parameters of the battery 40, it processes them into a format for transmission and outputs them to the communication circuit 11.

[0353] When the communication circuit 11 receives the transmission data from the transmission data generation circuit 15, it transmits the transmission data to the corresponding power conversion device 41 via the communication line 25. Figure 33 (S10).

[0354] exist Figure 33 In S10, after sending the operation plan of the battery 40 for all power conversion devices 41, S11 checks whether to stop the CEMS 31. If the CEMS 31 is stopped (Yes in S11), the process ends. On the other hand, if the CEMS 31 is not stopped, the process returns to S01 and continues.

[0355] As explained above, in Embodiment 1, when the operation plan (power target value) of the storage battery 40 is made facing the power conversion device 41, the control parameter of the virtual synchronous generator control installed in the static inverter of each power conversion device 41 is generated in accordance with the capacity of the static inverter and the power target value of each power conversion device 41. Thereby, in the period until the next operation plan is notified from the CEMS 31, even in the case where the power consumption of the load 600 or the power generation of the mega solar power plant 26 or the like changes, the excess or deficient power can be shared in the same proportional distribution ratio as the operation plan (power target value) of the storage battery 40.

[0356] Therefore, in the case where the power generation of the mega solar power plant 26 decreases by 50% due to, for example, a change in the amount of sunlight after the operation plan is just notified to all the power conversion devices 41, the deficient power of 50% is distributed in proportion to the ratio of the power target value calculated at the time of making the operation plan. For example, in the case where the power target value is controlled in accordance with the ratio thereof at the time of making the operation plan, when the charge and discharge power of each storage battery 40 is determined in such a manner that the SOC of all the storage batteries 40 becomes zero at substantially the same time, even if the power generation of the mega solar power plant 26 decreases by 50%, since the excess or deficient power is distributed in proportion to the ratio of the power target value, it is possible to control in such a manner that the SOC of all the storage batteries 40 becomes zero at substantially the same time.

[0357] Further, in Embodiment 1, the structure in which the control parameter of the virtual synchronous generator control is generated facing the static inverter of the power conversion device 41 using the inverter capacity and the power target value is explained, but is not limited thereto, for example, in the case where the capacity of the storage battery 40a is twice the inverter capacity of the power conversion device 41a, the capacity of the storage battery 40b is three times the inverter capacity of the power conversion device 41b, or the like, the ratio of the capacity of the storage battery 40 to the inverter capacity differs between the power conversion devices 41, the operation plan (power target value) of each storage battery 40 is generated considering the ratio of the capacity. Or, the same effect can be obtained by considering the above capacity ratio when the control parameter is generated.

[0358] (Action of the power conversion device 27 and the power conversion device 41)

[0359] Next, the action of the power conversion device 27 for the mega solar power plant and the power conversion device 41 for the storage battery will be explained using Figures 6 to 16 , Figure 40 and Figure 41 .

[0360] [Action of the power conversion device 27]

[0361] Use Figure 6 The operation of the power conversion device 27 for the megawatt solar power generation device is described.

[0362] After the megawatt solar power generation device 26 starts power generation, the direct current voltage inputted from the megawatt solar power generation device 26 to the first DC / DC converter 203 in the power conversion device 27 rises. The first control circuit 204 monitors the direct current voltage measured by the voltage meter 201. The first control circuit 204 shifts the power conversion device 27 from the standby state to the normal operation in the case where the direct current voltage exceeds a predetermined voltage value.

[0363] After the shift to the normal operation, the second control circuit 209 in the power conversion device 27 controls the first DC / AC converter 208. The control of the power conversion device 27 at the time of the normal operation is described below.

[0364] Reference Figure 6 The first control circuit 204 confirms whether the megawatt solar power generation device 26 is generating power. Specifically, the first control circuit 204 confirms whether the output voltage of the megawatt solar power generation device 26 measured by the voltage meter 201 exceeds a predetermined voltage. In the case where the output voltage exceeds the predetermined voltage, the first control circuit 204 notifies the second control circuit 209 of the information that the megawatt solar power generation device 26 can generate power.

[0365] The second control circuit 209 confirms whether power is supplied from the substation 20 to the power distribution system 24 (whether the power distribution system 24 is not out of power) on the basis of the alternating current voltage of the power distribution system 24 measured by the voltage meter 10 at the time of receiving the notification from the first control circuit 204.

[0366] In the case where the alternating current voltage measured by the voltage meter 210 is a predetermined voltage or more and it is confirmed that the power distribution system 24 is not out of power, the second control circuit 209 starts the DC / AC converter 208 and instructs the first control circuit 204 to start power generation of the megawatt solar power generation device 26.

[0367] Further, in Embodiment 1, the case where the direct current bus voltage of the direct current bus 205 is managed by the first DC / AC converter 208 at the time of the normal operation is described. In addition, in Embodiment 1, the power regenerated from the power conversion device 27 to the power distribution system 24 is managed by the current control of the first DC / AC converter 208, so that the distributed power source management device as a whole operates.

[0368] At the time of instructing the start of power generation of the megawatt solar power generation device 26 by the second control circuit 209, the fifth control circuit 54( Figure 8 ) of the first control circuit 204 instructs the MPPT control circuit 51( Figure 8The maximum power point tracking control of the megasolar power plant 26 is started.

[0369] The maximum power point tracking control is briefly explained. In the maximum power point tracking control, it is managed whether the last command value is larger than the last-but-one command value or smaller than the last-but-one command value. Also, the generated power of the megasolar power plant 26 measured this time is compared with the generated power of the megasolar power plant 26 measured last time, and in the case where the generated power is increased, the command value is changed in the same direction (increasing direction or decreasing direction) as last time.

[0370] Specifically, in the case where the generated power of the megasolar power plant 26 measured this time is increased compared with the generated power measured last time, the command value this time is increased when the last command value is larger than the last-but-one command value. On the other hand, the command value this time is decreased when the last command value is smaller than the last-but-one command value. Conversely, in the case where the generated power of the megasolar power plant 26 measured this time is decreased compared with the generated power measured last time, the command value this time is decreased when the last command value is larger than the last-but-one command value. On the other hand, the command value this time is increased when the last command value is smaller than the last-but-one command value. The command value this time is thus controlled, and the megasolar power plant 26 is controlled in such a manner that the output power becomes maximum.

[0371] The first DC / DC converter 203 operates the built-in step-up circuit in accordance with the command value output from the first control circuit 204, and thereby converts the first direct-current voltage output from the megasolar power plant 26 into a second direct-current voltage (the direct-current bus voltage of the direct-current bus 205) and outputs it.

[0372] After the generated power of the megasolar power plant 26 is started to be supplied from the first DC / DC converter 203, the second control circuit 209 outputs (regenerates) the generated power of the megasolar power plant 26 to the power distribution system 24 by controlling the first DC / AC converter 208. Specifically, the direct-current bus voltage of the direct-current bus 205 is monitored, and in the case where the direct-current bus voltage exceeds the control target value, the generated power is output in synchronization with the alternating-current voltage supplied from the power distribution system 24.

[0373] Next, the operation of the second control circuit 209 will be explained using Figure 9

[0374] In the second control circuit 209, the phase detection circuit 61 detects the zero-crossing point of the waveform of the alternating-current voltage of the power distribution system 24 measured by the voltage meter 210 Figure 1

[0375] ​​The first sine wave generating circuit 62 generates a reference sine wave synchronized with the waveform of the alternating current voltage of the power distribution system 24, based on information indicating the zero-crossing point detected by the phase detecting circuit 61 and the waveform of the alternating current voltage measured by the voltage meter 210. The first sine wave generating circuit 62 outputs the generated reference sine wave to the multiplier 65.

[0376] The voltage meter 206 measures the voltage of the direct current bus 205 and outputs the measurement value to the subtracter 63 and the sixth control circuit 67 in the current control circuit 60. Further, the current control circuit 60 uses a control method (current control) that outputs electric power in synchronization with the alternating current system voltage. This control method is a control method of a general solar power generation use power conversion device provided in a home.

[0377] The sixth control circuit 67 stores a target voltage of the direct current bus 205 and outputs the target voltage to the subtracter 63.

[0378] The current control circuit 60 controls the current output from the first DC / AC converter 208 in such a manner that the direct current bus voltage measured by the voltage meter 206 becomes the target voltage. The output of the subtracter 63 is input to the first PI control circuit 64. The first PI control circuit 64 performs PI control in such a manner that the output of the subtracter 63 becomes zero. The output of the first PI control circuit 64 is input to the multiplier 65 and is converted into a current command value by being multiplied by the reference sine wave from the first sine wave generating circuit 62.

[0379] The current command value output from the multiplier 65 is input to the subtracter 66. The subtracter 66 calculates the deviation of the current command value from the alternating current value of the power distribution system 24 measured by the current meter 211 and inputs the calculated deviation to the second PI control circuit 68.

[0380] The second PI control circuit 68 performs PI control in such a manner that the deviation output from the subtracter 66 becomes zero. The first PWM converter 69 generates a command value for the first DC / AC converter 208 by performing PWM control with respect to the output of the second PI control circuit 68. The first DC / AC converter 208 outputs an alternating current in accordance with the command value supplied from the first PWM converter 69.

[0381] In addition, in a case where the alternating current voltage (alternating current effective voltage) measured by the voltage meter 210 exceeds a predetermined voltage value or in a case where the CEMS 31 notifies of a request to suppress the generated electric power of the megawatt solar power generation device 26, the fifth control circuit 54 in the first control circuit 204 outputs a command to the second control circuit 202 to stop the operation of the megawatt solar power generation device 26. Figure 8) switches the control of the megawatt solar power generation device 26 from the MPPT control to the voltage control. Specifically, the fifth control circuit 54 controls the direct current voltage output from the megawatt solar power generation device 26 in such a manner that the alternating current voltage (alternating current effective voltage) measured by the voltage meter 210 converges to a predetermined voltage range. Alternatively, the fifth control circuit 54 controls the output voltage of the megawatt solar power generation device 26 in such a manner that the power generation electric power of the megawatt solar power generation device 26 converges to a power range notified from the CEMS 31.

[0382] Further, the first switching circuit 53 ( Figure 8 ) switches the output of the MPPT control circuit 51 and the output of the voltage control circuit 52 in accordance with a switching control signal supplied from the fifth control circuit 54.

[0383] The sixth control circuit 67 collects the measurement results relating to the direct current bus 205 measured by the voltage meter 206 and the current meter 207, the measurement results relating to the power distribution system 24 measured by the voltage meter 210 and the current meter 211, the state information of the first DC / DC converter 203 output from the first control circuit 204, and the like, and notifies the collected information to the CEMS 31 and the like via the communication I / F 212.

[0384] In addition, the sixth control circuit 67 also notifies the CEMS 31 of the effective voltage of the power distribution system 24 measured by an effective voltage measurement section not shown, or the information relating to the effective power and the ineffective power of the alternating current system measured by an effective / ineffective power measurement section not shown, via the communication I / F 212, and also notifies the measurement results of the effective voltage, the effective power, and the like of the alternating current system to the fifth control circuit 54.

[0385] As described above, in the case where the effective value of the alternating current system voltage exceeds a predetermined value, the fifth control circuit 54 suppresses the rise of the alternating current system voltage by switching the control of the megawatt solar power generation device 26 from the MPPT control to the voltage control.

[0386] [Operation of the power conversion device 41]

[0387] Next, the operation of the power conversion device 41 for the storage battery will be described using Figure 7 , Figures 10 to 16 , Figure 40 and Figure 41 .

[0388] In Embodiment 1, the virtual synchronous generator control is installed in the power conversion device 41, so the second DC / AC converter 408 operates as a voltage source by performing the voltage control. That is, the third control circuit 404 ( Figure 7 ) controls in such a manner that the voltage of the direct current bus 405 becomes a constant value. Hereinafter, the operation of the power conversion device 41 for the storage battery will be described using Figure 10 The operation of the third control circuit 404 will be described.

[0389] The voltage of the DC bus 405 is measured by the voltage meter 406. The measured value of the voltage meter 406 is input to the charge control circuit 71, the discharge control circuit 72, and the seventh control circuit 74.

[0390] The charge control circuit 71 and the discharge control circuit 72 control the charge power or the discharge power in such a manner that the voltage of the DC bus 405 becomes the target voltage output from the seventh control circuit 74. Specifically, in the case where the battery 40 is discharged, the control is performed in such a manner that the discharge power is reduced when the voltage of the DC bus 405 is greater than the target voltage, and on the other hand, the discharge power is increased when the voltage of the DC bus 405 is less than the target voltage, thereby making the voltage of the DC bus 405 coincide with the target voltage.

[0391] On the other hand, in the case where the battery 40 is charged, the control is performed in such a manner that the charge power is increased when the voltage of the DC bus 405 is greater than the target voltage, and on the other hand, the charge power is reduced when the voltage of the DC bus 405 is less than the target voltage, thereby making the voltage of the DC bus 405 coincide with the target voltage.

[0392] Further, the output of the charge control circuit 71 and the output of the discharge control circuit 72 are switched by the second switching circuit 73. The seventh control circuit 74 outputs a switching control signal to the second switching circuit 73 in accordance with the charge and discharge operation of the battery 40.

[0393] Next, the operation of the fourth control circuit 409 Figures 11 to 16 will be described using Figure 40 . Figure 7

[0394] Figure 40 is a flowchart for explaining the operation of the power conversion device 41.

[0395] As shown in Figure 40 , after the start of the process, the fourth control circuit 409 initializes various control parameters by S200. Next, the fourth control circuit 409 collects the voltage values measured by the voltage meters 401, 406, 410, the current values measured by the current meters 402, 407, 411, and the state information of the battery 40 by S201. Further, the measured value of the voltage meter 410 is an alternating voltage, so the eighth control circuit 87 Figure 11 ​The effective value of the alternating current is calculated in the eighth control circuit 87, and the effective value is used as the current value. The measurement value of the ammeter 411 is an alternating current, so the effective value of the alternating current is calculated in the eighth control circuit 87, and the effective value is used as the current value. The charge / discharge power calculation circuit (not shown) in the seventh control circuit 74 calculates the charge / discharge power of the storage battery and the charge / discharge power amount on the basis of the collected data.

[0396] The alternating voltage of the power distribution system 24 measured by the voltmeter 410 is input to the alternating frequency detection circuit 81 Figure 11 The alternating frequency detection circuit 81 detects the zero-crossing point of the waveform of the alternating voltage through S202.

[0397] Figure 12 is a block diagram showing the structure of the alternating frequency detection circuit 81 shown in Figure 11 As shown in Figure 12 , the measurement value of the voltmeter 410 is input to the phase detection circuit 810. The phase detection circuit 810 detects the zero-crossing point of the alternating voltage through S202 of the above-described configuration. Figure 40 Further, in Embodiment 1, the zero-crossing point indicates the point and the time at which the waveform of the alternating voltage measured by the voltmeter 410 is switched from negative to positive. The phase detection circuit 810 outputs information indicating the detected zero-crossing point to the frequency detection circuit 811.

[0398] The frequency detection circuit 811 calculates the period of the alternating voltage on the basis of the time of the last detected zero-crossing point by the phase detection circuit 810 and the time of the present detected zero-crossing point. The frequency detection circuit 811 calculates the frequency of the alternating voltage on the basis of the calculated period.

[0399] The second sine wave generation circuit 812 outputs the zero-crossing point information detected by the phase detection circuit 810 and the frequency information of the alternating voltage detected by the frequency detection circuit 811 as sine wave information. The zero-crossing point information and the frequency information are output to the inverter current control circuit 84, the inverter voltage control circuit 85, the virtual synchronous generator control circuit 83, and the eighth control circuit 87.

[0400] Returning to Figure 40 , in a case where the zero-crossing point is detected in S202 (YES in S202), the phase detection circuit 810 sets the zero-crossing point detection flag through S203. In a case where the processing of S203 is ended, or in a case where the zero-crossing point is not detected in S202 (NO in S202), the fourth control circuit 409 controls the second DC / AC converter 408 through S204.

[0401] Hereinafter, the use of Figure 11 and Figure 41, which indicates the control of the second DC / AC converter 408.

[0402] As described above, the power conversion device 41 is installed with the virtual synchronous generator control, so the second DC / AC converter 408 is controlled as a voltage source. That is, the second DC / AC converter 408 is voltage-controlled. Therefore, in a case where the power supplied to the power distribution system 24 is insufficient, the second DC / AC converter 408 is controlled in a manner to increase the output power. On the other hand, in a case where the power supplied to the power distribution system 24 becomes excessive, the second DC / AC converter 408 is controlled in a manner to decrease the output power.

[0403] Figure 41 is a flowchart for explaining details of the control process of the second DC / AC converter 408.

[0404] As Figure 41 indicated, by S2041, the active power calculation circuit 82 Figure 11 , after calculating the power value from the measured values of the voltage meter 410 and the current meter 411, by S2042, integrates the calculated power value. In a case where the zero-crossing point detection flag is set (YES in S2043), the active power calculation circuit 82 goes to S2044, stores the integrated value of the active power value for one cycle of the alternating voltage to a storage circuit (not shown) in the eighth control circuit 87, and initializes the integrated value to zero by S2045.

[0405] In a case where the process of S2045 is ended, or in a case where the zero-crossing point detection flag is not set (NO in S2043), by S2046, the inverter voltage control circuit 85 generates the command value of the second DC / AC converter 408.

[0406] After the command value is generated in S2046, the virtual synchronous generator control circuit 83 Figure 11 performs the virtual synchronous generator control. In Embodiment 1, one cycle of the alternating voltage is set as the control period. Further, as for the control period, an integer multiple of one cycle of the alternating voltage or a predetermined period such as one second period can be set.

[0407] Figure 14 is a block diagram showing the structure of the virtual synchronous generator control circuit 83.

[0408] The eighth control circuit 87 Figure 11 , when it is determined that the control timing comes, instructs the virtual synchronous generator control circuit 83 to generate information on the frequency and the phase used in the voltage control. In Embodiment 1, at the zero-crossing point, the third sine wave generation circuit 851 in the inverter voltage control circuit 85 is updated, and the virtual synchronous generator control circuit 83 is instructed to generate the information on the frequency and the phase. Figure 13 The frequency and phase of the generated sine wave. Therefore, in Embodiment 1, the control period described above becomes the period of the zero-crossing point detected by the AC frequency detection circuit 81.

[0409] like Figure 14 As shown, in the virtual synchronous generator control circuit 83, the subtractor 832 receives input from the AC frequency detection circuit 81 (…). Figure 11 The measured value of the frequency of the input AC voltage is subtracted from the reference frequency Fref (e.g., 60Hz) input by the eighth control circuit 87, and the result of the subtraction is output to the speed controller control circuit 833. Figure 15 It is shown Figure 14 The diagram shows a detailed structural block diagram of the speed controller control circuit 833.

[0410] like Figure 15 As shown, in the speed controller control circuit 833, the multiplier 91 converts the subtractor 832 ( Figure 14 The output of the multiplier 91 is multiplied by the control parameter (-1 / Kgd) notified from the eighth control circuit 87. The multiplier 91 inputs the multiplication result into the first-order delay system model 92.

[0411] Furthermore, the speed regulation rate Kgd and the speed governor time constant Tg used in the speed governor control circuit 833 are set to a register (not shown) via the eighth control circuit 87 and used, based on the parameters notified from CEMS31.

[0412] The first-order delay system model 92 is used to simulate the first-order delay system (1 / (1+s×Tg)) by using the time constant Tg notified from the eighth control circuit 87 as described above, and the calculation result is output to the limiting circuit 93.

[0413] Limiting circuit 93 imposes a limit on the input data. Specifically, limiting circuit 93 limits the output power of second DC / AC converter 408 in a manner that does not exceed the power capacity of second DC / AC converter 408.

[0414] Return to Figure 14 Adder 835 adds the output of speed controller control circuit 833 to the power target value Pref output from eighth control circuit 87. Furthermore, regarding the power target value Pref, the eighth control circuit 87 outputs parameters notified from CEMS 31.

[0415] Subtractor 836 subtracts the output of adder 835 from the output of effective power calculation circuit 82. Figure 11 The actual data value of the effective power output is calculated, and the subtraction result is output to the particle system operation circuit 837. Figure 16 It is shown Figure 15The block diagram showing the detailed structure of the particle system operational circuit 837 is shown.

[0416] like Figure 16 As shown, subtractor 101 is derived from subtractor 836 ( Figure 14 The output of the multiplier 103 is subtracted from the output of the multiplier 103, and the subtraction value is output to the integrator 102.

[0417] Integrator 102 divides the subtraction result of subtractor 101 by the inertia constant M output from the eighth control circuit 87, and integrates the division result. The output Δω of integrator 102 is equivalent to the difference between the angular velocity (2×π×60Hz) for the frequency of the AC voltage. The output Δω of integrator 102 is input to multiplier 103 and divider 104.

[0418] Multiplier 103 multiplies the output Δω of integrator 102 with the braking coefficient Dg provided from the eighth control circuit 87, and outputs the multiplication result to subtractor 101.

[0419] Divider 104 transforms the output Δω of integrator 102 into a difference Δf with the reference frequency Fref (60Hz) by dividing Δω by 2×π. Adder 105 adds the output Δf of divider 104 to the reference frequency Fref (60Hz) to generate a voltage control circuit 85 for use in inverter voltage control. Figure 11 The frequency (Fref+Δf) used for voltage control in )

[0420] Furthermore, the parameters of inertia constant M and braking coefficient Dg used in the particle system operation circuit 837 are set to a register (not shown) via the eighth control circuit 87, and the parameters set to the register are used.

[0421] The frequency information (Fref+Δf) output from adder 105 is input to phase calculation circuit 106. The operation of phase calculation circuit 106 will be described below.

[0422] In implementation 1, the phase calculation circuit 106 is used to calculate the phase of the adder 105 ( Figure 16 The frequency information output is integrated and output as phase information when the inverter voltage control circuit 85 performs voltage control.

[0423] From the particle system operation circuit 837 ( Figure 16 The phase and frequency information output are processed by the second sine wave generation circuit 812 within the AC frequency detection circuit 81. Figure 12 The third sine wave generation circuit 851, which is input to the inverter voltage control circuit 85, is... Figure 13). The third sine wave generation circuit 851 generates a target value of the alternating voltage output from the power conversion device 41 based on the input information.

[0424] Returning to Figure 40 After the process of the virtual synchronous generator control in S205 is completed, the fourth control circuit 409 confirms whether or not a transmission request of the measurement data is accepted from the CEMS 31 through S206. In a case where the transmission request is accepted from the CEMS 31 (YES in S206), the eighth control circuit 87 (YES in S207) transmits the measurement data to the CEMS 31 via the communication I / F 412 (YES in S208) through S209. Figure 11 Figure 7

[0425] On the other hand, in a case where the measurement data is transmitted in S207 or in a case where no transmission request is received from the CEMS 31 (NO in S206), the eighth control circuit 87 proceeds to S208 to confirm whether or not control information is received from the CEMS 31.

[0426] In a case where the control information is received from the CEMS 31 (YES in S208), the eighth control circuit 87 sets a reception flag of the control information through S209. In a case where the process of S209 is completed or in a case where no control information is received from the CEMS 31 (NO in S208), the eighth control circuit 87 confirms whether or not a zero-crossing point detection flag is set through S210. In a case where the zero-crossing point detection flag is not set (NO in S210), the process returns to S201.

[0427] On the other hand, in a case where the zero-crossing point detection flag is set (YES in S210), the second sine wave generation circuit 812 (YES in S211) takes in information of the frequency and the phase of the system voltage and resets the zero-crossing point detection flag in S212. Figure 12 After the zero-crossing point detection flag is reset in S212, the second sine wave generation circuit 812 updates the information of the frequency and the phase of the system voltage (the zero-crossing point timing information in Embodiment 1) to the information taken in in S211 through S213.

[0428] After the process of S213 is completed, the eighth control circuit 87 confirms whether or not the control information is received from the CEMS 31 (whether or not the reception flag of the control information is set) through S214. In a case where the reception flag is not set (NO in S214), the process returns to S201.

[0429]

[0430] ​​​On the other hand, in a case where the reception flag is set (YES in S214), the eighth control circuit 87 replaces the frequency target value (reference frequency Fref) and the power target value Pref with the received data, respectively, through S215. The eighth control circuit 87 updates the control parameters of the virtual synchronous generator control to the control parameters (speed adjustment rate Kgd, brake coefficient Dg, and inertia constant M) received in S216.

[0431] After the update of the control parameters in S216 is completed, the eighth control circuit 87 clears (resets) the register (not shown) in which the reception flag is set, and returns the process to S201.

[0432] As explained above, according to the distributed power management apparatus relating to Embodiment 1, even in a case where the demand balance greatly changes after the operation plan (power target value) of the storage batteries 40a to 40c made by the CEMS 31 is just notified to the corresponding power conversion devices 41a to 41c, respectively, the proportional distribution ratio of the output power of the power conversion devices 41a to 41c can be made substantially equal to the ratio of the power target values at the time of making the operation plan. Thereby, in a case where the operation plan (discharge plan) is made in a manner that the SOCs of the storage batteries 40a to 40c become substantially zero at the same time after several hours, or in a case where the operation plan (charge plan) is made in a manner that the storage batteries 40a to 40c become substantially fully charged at the same time, even in a case where the consumption power of the load 600 or the power generation power of the mega solar power plant 26 greatly changes from the assumed power at the time of making the operation plan, although the assumed time is deviated, the SOCs of the storage batteries 40a to 40c can be made substantially zero at the same time or the storage batteries 40a to 40c can be made substantially fully charged at the same time, and the assumed operation plan can be followed.

[0433] Further, in the conventional virtual synchronous generator control technology, the power conversion devices 41a to 41c equally share the excess or insufficient power, so the proportional distribution ratio of the power of the power conversion device 41 whose power target value is relatively small becomes high, and the corresponding storage battery 40 sometimes becomes zero in the SOC before the other storage batteries 40. In contrast, according to Embodiment 1, the excess or insufficient power can be proportionally distributed in accordance with the ratio of the power target values set in the operation plan, so the proportional distribution ratio of the power of the storage battery 40 whose SOC is low (i.e., whose power target value is small) can be suppressed to be low.

[0434] Embodiment 2.

[0435] In Embodiment 1, a structure is described in which the CEMS 31 generates control parameters of the virtual synchronous generator control installed in the power conversion device 41 and transmits the control parameters to the power conversion device 41. In Embodiment 2, a structure is described in which the CEMS 31 transmits parameters required for generation of the control parameters to the power conversion device 41, and the power conversion device 41 generates the control parameters using the received parameters.

[0436] The CEMS 31 in Embodiment 2 differs from the CEMS 31 in Embodiment 1 only in the structure of the control parameter generation circuit 13 Figure 5 ). Hereinafter, the distributed power management device according to Embodiment 2 is described focusing on the parts different from Embodiment 1.

[0437] Figure 42 is a block diagram showing the structure of the control parameter generation circuit 13 according to Embodiment 2. Figure 42 The control parameter generation circuit 13 shown is a structure obtained by removing the control parameter generation circuit 133 and the virtual synchronous generator model 134 from the control parameter generation circuit 13 shown in Figure 5

[0438] In Embodiment 2, the CEMS 31 generates the slope of the ΔP / ΔF characteristic, and transmits the generated slope of the ΔP / ΔF characteristic, the power target value Pref, and system information (the limit value of the system frequency (Fref±ΔFmax), the response performance of the virtual synchronous generator control, and the like) to the power conversion device 41. The power conversion device 41 generates the control parameters using the received data from the CEMS 31 and the capacity of its static inverter.

[0439] In Embodiment 2, the structure in which the CEMS 31 generates the ΔP / ΔF characteristic is described, but the present application is not limited to this, and the CEMS 31 can be configured to transmit all information required for generation of the control parameters or data generated in the middle process to the power conversion device 41, and the power conversion device 41 can generate the control parameters using the received data. By this, the amount of data transmitted from the CEMS 31 to the power conversion device 41 can be reduced.

[0440] As shown in Figure 42 , the control parameter generation circuit 13 according to Embodiment 2 has a reference ΔP / ΔF characteristic calculation circuit 131, a ΔP / ΔF characteristic calculation circuit 132, a management circuit 135, and a control circuit 137.

[0441] The reference ΔP / ΔF characteristic calculation circuit 131 calculates the reference ΔP / ΔF characteristic based on information about the capacity of the static inverter (the second DC / AC converter 408) of the power conversion device 41a to 41c.​

[0442] The ΔP / ΔF characteristic calculation circuit 132 calculates the ΔP / ΔF characteristic based on the reference ΔP / ΔF characteristic and the circuit 14 (made from the operation plan). Figure 5 The power target value Pref is generated, and the ΔP / ΔF characteristic is calculated.

[0443] The management circuit 135 stores and manages information such as the slope of the ΔP / ΔF characteristic output from the ΔP / ΔF characteristic calculation circuit 132 and the power target value Pref, which are not shown in the figure.

[0444] The control circuit 137 manages the operation of the reference ΔP / ΔF characteristic calculation circuit 131, the ΔP / ΔF characteristic calculation circuit 132, and the management circuit 135.

[0445] Next, the operation of CEMS31 according to Embodiment 2 will be explained. Compared to the operation of CEMS31 according to Embodiment 1, the only difference in the operation of CEMS31 according to Embodiment 2 is the generation and processing of control parameters for virtual synchronous generator control. Figure 34 S056 and Figure 35 The differences are as follows. The actions of the different parts are explained below.

[0446] Figure 43 This illustrates the process of generating control parameters for virtual synchronous generator control. Figure 34 The flowchart of S056). The control parameter generation circuit 13 within CEMS31 ( Figure 42 )implement Figure 43 The processing shown.

[0447] like Figure 43 As shown, after the processing begins, the control circuit 137 first collects data based on the information provided in step S10561. Figure 34 The power target value Pref is calculated based on the charging and discharging power of the battery 40 during the next 30 minutes, generated in S054; the inverter capacity Cinv of the second DC / AC converter 408 within the power conversion device 41; and information about the power distribution system 24 (system frequency limit value (Fref±ΔFmax) and response performance of the virtual synchronous generator control). In Embodiment 2, in Figure 34 In S054, the battery operation plan control circuit 141 is set up. Figure 4 Create the power target value Pref for each power conversion device 41.

[0448] After information is collected in S10561, the reference ΔP / ΔF characteristic calculation circuit 131 is used via S10562. Figure 42) The reference ΔP / ΔF characteristic is calculated. The method of creating the reference ΔP / ΔF characteristic is the same as the method described in Embodiment 1. That is, in the discharging mode or the charging mode of the storage battery 40, half of the inverter capacity serving as a reference is set as the power target value (the discharging case is set as positive, and the charging case is set as negative), so that the frequency of the alternating voltage in the case where the static inverter discharges the maximum power (in the charging case, the case where the charging power becomes zero) becomes equal to the lower limit frequency (Fref-ΔFmax), and the frequency of the alternating voltage in the case where the discharging power of the static inverter is zero (in the charging case, the case where the maximum charging power is discharged) becomes equal to the upper limit frequency (Fref+ΔFmax), and the reference ΔP / ΔF characteristic is created in this manner.

[0449] On the other hand, in the case of the charging and discharging mode of the storage battery 40, half of the inverter capacity serving as a reference is set as the power target value, so that the frequency of the alternating voltage in the case where the static inverter is charged with the maximum power becomes equal to the upper limit frequency, and the frequency of the alternating voltage in the case where the charging power of the static inverter becomes zero becomes equal to the lower limit frequency, and the reference ΔP / ΔF characteristic is created in this manner.

[0450] After the reference ΔP / ΔF characteristic is calculated in S10562, the ΔP / ΔF characteristic calculation circuit 132 creates the ΔP / ΔF characteristic by S10563. Specifically, as shown in FIG. 10, after the reference ΔP / ΔF characteristic is generated, the reference ΔP / ΔF characteristic calculation circuit 131 outputs the slope of the generated reference ΔP / ΔF characteristic to the control circuit 137 and the ΔP / ΔF characteristic calculation circuit 132. Figure 42

[0451] The ΔP / ΔF characteristic calculation circuit 132 calculates the ΔP / ΔF characteristic in accordance with the power target value Pref notified from the control circuit 137. Specifically, the ΔP / ΔF characteristic calculation circuit 132 limits the power target value Pref to the inverter capacity Cinv in the case where the power target value Pref collected from the control circuit 137 exceeds the inverter capacity Cinv. Also, the ΔP / ΔF characteristic calculation circuit 132 calculates the slope of the ΔP / ΔF characteristic in the discharging mode or the charging mode of the storage battery 40 in such a manner that the slope of the ΔP / ΔF characteristic = the slope of the reference ΔP / ΔF characteristic x (Cinv x 0.5) / Pref.

[0452] ​After calculating the slope of the ΔP / ΔF characteristic, the control circuit 137 outputs the slope of the ΔP / ΔF characteristic, the electric power target value Pref, and system information (Fref ± ΔFmax, response performance of the virtual synchronous generator control, etc.) to the management circuit 135. The management circuit 135 stores the input information to a storage section not shown for each electric power conversion device 41. The subsequent operation is the same as that in Embodiment 1, so the description is omitted.

[0453] Next, the operation of the electric power conversion device 41 according to Embodiment 2 will be described.

[0454] Figure 44 is a flowchart of the operation of the fourth control circuit 409. Figure 11

[0455] As shown in Figure 44 , after the operation of the electric power conversion device 41 is started, the fourth control circuit 409 initializes various control parameters to predetermined initial values by S200, as in Embodiment 1.

[0456] After initializing the various control parameters, the fourth control circuit 409 collects the measurement values of the voltage meters 401, 406, 410 and the current meters 402, 407, 411 and the state information (SOC, etc.) of the storage battery 40 by S201. In Embodiment 2, the fourth control circuit 409 calculates the charge and discharge electric power of the storage battery 40 and the charge and discharge electric power amount on the basis of the collected data.

[0457] Next, the fourth control circuit 409 detects the zero-crossing point of the alternating voltage by S202. Upon detecting the zero-crossing point (YES in S202), the operation proceeds to S203, and the zero-crossing point detection flag is set. Also, the zero-crossing point, as in Embodiment 1, indicates the point and time at which the waveform of the alternating voltage measured by the voltage meter 410 is switched from negative to positive. The alternating frequency detection circuit 81 Figure 11 ) calculates the period of the alternating voltage on the basis of the time information of the last detected zero-crossing point and the time information of the present detected zero-crossing point by the phase detection circuit 810 Figure 12 ) and calculates the frequency of the alternating voltage on the basis of the calculated result.

[0458] The second sine wave generation circuit 812 Figure 12 ) outputs the zero-crossing point information detected by the phase detection circuit 810 and the frequency information of the alternating voltage detected by the frequency detection circuit 811 as the sine wave information.

[0459] ​In a case where the processing of S203 ends or in a case where no zero-crossing point is detected in S202 (NO in S202), the fourth control circuit 409 controls the second DC / AC converter 408 through S204. As with Embodiment 1, the fourth control circuit 409 controls the second DC / AC converter 408 as a voltage source. Thus, the fourth control circuit 409 increases the output power of the second DC / AC converter 408 in a case where the power supplied to the power distribution system 24 is insufficient, and decreases the output power of the second DC / AC converter 408 in a case where the power supplied to the power distribution system 24 becomes excessive.

[0460] The active power calculation circuit 82( Figure 11 ) calculates the active power value from the measurement values of the voltage meter 410 and the current meter 411, and integrates the calculated active power value. In a case where the zero-crossing point detection flag is set, the active power calculation circuit 82 stores the integrated value of the active power for one cycle of the alternating voltage to the storage circuit in the eighth control circuit 87, and initializes the integrated value to zero. After the active power is calculated, the inverter voltage control circuit 85 generates an instruction value for controlling the second DC / AC converter 408.

[0461] After the instruction value is generated in S204, the fourth control circuit 409 executes the virtual synchronous generator control through S205. As with Embodiment 1, one cycle of the alternating voltage is set as the control period. The eighth control circuit 87( Figure 11 ) instructs the virtual synchronous generator control circuit 83( Figure 11 ) to generate information of the frequency and the phase of the alternating voltage used in the voltage control, when it is determined that the control timing has come. In Embodiment 2, as with Embodiment 1, the third sine wave generation circuit 851( Figure 13 ) in the inverter voltage control circuit 85 is updated at the zero-crossing point.

[0462] In the virtual synchronous generator control circuit 83( Figure 14 ), the subtracter 832 calculates a deviation of the measured value of the frequency of the alternating voltage detected by the alternating frequency detection circuit 81( Figure 11 ) from the reference frequency Fref output from the eighth control circuit 87, and outputs the calculated deviation to the governor control circuit 833.

[0463] The governor control circuit 833( Figure 15) The deviation output from the subtracter 832 is multiplied by the control parameter (-1 / Kgd) notified from the eighth control circuit 87 by the multiplier 91, and the multiplication result is output to the first-order lag system model 92. Further, as for the speed adjustment rate Kgd and the governor time constant Tg used by the governor control circuit 833, parameters generated by the eighth control circuit 87 from information notified from the CEMS 31 and set to a register not shown are used.

[0464] The first-order lag system model 92 performs an operation for simulating a first-order lag system (1 / (1+s x Tg)) using the time constant Tg notified from the eighth control circuit 87 as in Embodiment 1, and outputs the operation result to the limiter circuit 93. The limiter circuit 93 imposes a limit on the output power of the second DC / AC converter 408 in such a manner that the power capacity of the second DC / AC converter 408 is not exceeded.

[0465] The output of the governor control circuit 833 is added to the power target value Pref output from the eighth control circuit 87 by the adder 835. Figure 14 Further, the power target value Pref is a parameter notified from the CEMS 31. The subtracter 836 calculates the deviation of the output of the adder 835 from the measured value of the effective power calculated by the effective power calculation circuit 82 Figure 11

[0466] In the particle system operation circuit 837, the subtracter 101 calculates the deviation of the output of the subtracter 836 Figure 16 Figure 14 ​​The output of subtractor 101 is calculated to deviate from the output of multiplier 103, and the calculated deviation is output to integrator 102. Integrator 102 divides the output of subtractor 101 by the inertia constant M output from the eighth control circuit 87 and integrates the division result. The output Δω of integrator 102 (the difference between the angular velocity of the AC voltage frequency and the integrator 102) is input to multiplier 103 and divider 104. Multiplier 103 multiplies the output Δω of integrator 102 by the braking coefficient Dg output from the eighth control circuit 87 and outputs the multiplication result to subtractor 101. Divider 104 transforms Δω into Δf (the difference between the AC voltage frequency and the integrator 102) by dividing the output Δω of integrator 102 by 2×π. Adder 105 generates the frequency used in voltage control in inverter voltage control circuit 85 by adding the output of divider 104 to the reference frequency Fref (60Hz) of AC voltage. Furthermore, the inertia constant M and braking coefficient Dg used by the particle system operation circuit 837 are parameters generated and set into a register (not shown) using information from the CEMS31 by the eighth control circuit 87. The frequency information output from the adder 105 is output to the phase calculation circuit 106. The phase calculation circuit 106 generates the phase information used in the voltage control of the inverter voltage control circuit 85 by integrating the frequency information output from the adder 105.

[0467] The phase information and frequency information output from the particle system operation circuit 837 are transmitted through the second sine wave generation circuit 812 within the AC frequency detection circuit 81. Figure 12 The third sine wave generation circuit 851, which is input to the inverter voltage control circuit 85, is... Figure 13 The third sine wave generating circuit 851 generates the target value of the AC voltage output from the power conversion device 41.

[0468] Return to Figure 44 After the virtual synchronous generator control is completed in S205, the fourth control circuit 409 confirms in S206 whether the request to send measurement data has been accepted from CEMS31. If the request to send data has been accepted from CEMS31 (Yes in S206), the process proceeds to S207, where the fourth control circuit 409 notifies CEMS31 of the measurement data via communication I / F412.

[0469] In a case where the measurement data is transmitted in S207 or in a case where the transmission request from the CEMS 31 is not received (NO in S206), the fourth control circuit 409 confirms whether or not the control information is received from the CEMS 31 through S208. In a case where the control information is received (YES in S208), the fourth control circuit 409 sets a reception flag of the control information. In a case where the reception flag is set in S209 or in a case where the control information is not received from the CEMS 31 (NO in S208), the fourth control circuit 409 confirms whether or not the zero-crossing point detection flag is set through S210. In a case where the zero-crossing point detection flag is not set (NO in S210), the process returns to S201.

[0470] On the other hand, in a case where the zero-crossing point detection flag is set (YES in S210), the fourth control circuit 409 proceeds to S211, takes the information of the frequency and the phase of the alternating voltage into the second sine wave generating circuit 812, and resets the zero-crossing point detection flag through S212.

[0471] After the zero-crossing point detection flag is reset in S212, the fourth control circuit 409 updates the information of the frequency and the phase of the alternating voltage to the frequency and the phase taken into the second sine wave generating circuit 812 in S211, respectively, through S213.

[0472] After the information of the frequency and the phase of the alternating voltage is updated in S213, the fourth control circuit 409 confirms whether or not the control information from the CEMS 31 is received (whether or not the reception flag is set) through S214. In a case where the reception flag is not set (NO in S214), the process returns to S201. On the other hand, in a case where the reception flag is set (YES in S214), the fourth control circuit 409 replaces the frequency target value (reference frequency Fref) and the power target value Pref to the received data, respectively, through S215.

[0473] After the information for generating the control parameter is received in S216, the eighth control circuit 87 generates the control parameter of the virtual synchronous generator control. Specifically, the control parameter is generated in accordance with the slope of the ΔP / ΔF characteristic generated by the CEMS 31, the system information (reference frequency Fref, power target value Pref, ΔFmax, and the like), and the own inverter capacity. In Embodiment 2, the eighth control circuit 87 stores the relationship between the damping coefficient Dg and the system frequency shown in FIG. 9 as table data for each of the plurality of speed adjustment rates Kgd. The eighth control circuit 87 refers to the table data in accordance with the information of ΔFmax, thereby retrieving the combination of the speed adjustment rate Kgd and the damping coefficient Dg that coincide with the slope of the ΔP / ΔF characteristic. Figure 19 After the information for generating the control parameter is received in S216, the eighth control circuit 87 generates the control parameter of the virtual synchronous generator control. Specifically, the control parameter is generated in accordance with the slope of the ΔP / ΔF characteristic generated by the CEMS 31, the system information (reference frequency Fref, power target value Pref, ΔFmax, and the like), and the own inverter capacity. In Embodiment 2, the eighth control circuit 87 stores the relationship between the damping coefficient Dg and the system frequency shown in FIG. 9 as table data for each of the plurality of speed adjustment rates Kgd. The eighth control circuit 87 refers to the table data in accordance with the information of ΔFmax, thereby retrieving the combination of the speed adjustment rate Kgd and the damping coefficient Dg that coincide with the slope of the ΔP / ΔF characteristic.

[0474] Furthermore, the method for generating control parameters for controlling the virtual synchronous generator installed in the power conversion device 41 is not limited to the method described above. For example, it is also possible to use a built-in virtual synchronous generator control model or a built-in formula representing the virtual synchronous generator control, as in Embodiment 1.

[0475] After generating the speed adjustment rate Kgd and the braking coefficient Dg, the eighth control circuit 87 calculates the inertial constant M based on the time constant information of the mass system operation circuit. In the method for calculating the inertial constant M, as described in Embodiment 1, the above formula (3) is used to calculate the inertial constant M in such a way that the time constant notified from CEMS31 is equal to (M / Dg).

[0476] exist Figure 44 After the control parameters are generated in S220, the eighth control circuit 87 modifies (updates) the control parameters through S216. After modifying (updating) the control parameters, the eighth control circuit 87 clears (resets) the register (not shown) with the receive flag set, causing the processing to return to S201.

[0477] As explained above, according to Embodiment 2, in a structure in which multiple power conversion devices 41, each equipped with virtual synchronous generator control, are arranged in the power distribution system 24, even if the power consumption of the load 600 or the power generated by the megawatt-level solar power generation equipment 26 changes, the multiple power conversion devices 41 can share the excess or insufficient power according to the proportional allocation ratio of the operation plan (power target value) generated by the CEMS 31.

[0478] Furthermore, in Embodiment 2, by configuring a portion of the functions installed in CEMS 31 to be integrated into the power conversion device 41, the processing load on CEMS 31 can be reduced. For example, in Embodiment 1, when the virtual synchronous generator control is installed in a household battery installed by a general customer, CEMS 31 needs to generate control parameters for the virtual synchronous generator control in hundreds to thousands of household batteries. On the other hand, according to Embodiment 2, by integrating a portion of the virtual synchronous generator control functions into the household battery, the processing load on CEMS 31 can be reduced.

[0479] Furthermore, when the control circuits of virtual synchronous generators installed in multiple power conversion devices 41 or household batteries have different structures, the CMES31 needs to have multiple types of control parameters generated by the CEMS31. Figure 5The virtual synchronous generator model shown, or the table data shown in the plurality of kinds of embodiment 2. In addition, there is also a case where the number of generated control parameters differs for each virtual synchronous generator control circuit. Even in such a case, by configuring the power conversion device 41 and the household storage battery each to generate a control parameter, it is possible to make the processing of the CEMS 31 simple.

[0480] In addition, in the embodiments 1 and 2, by configuring to generate the control parameters according to the capacities of the static inverters of the respective power conversion devices 41 and the power target values at the time of making the operation plan (power target value) facing the power conversion device 41, even in a case where the consumption power of the load 600 or the power generation power of the mega solar power plant 26 has changed during a period until the next operation plan is notified from the CEMS 31, it is possible to share the excess or deficient power in the same proportion as the proportion of the operation plan (power target value).

[0481] Thus, even in a case where, for example, the amount of sunshine changes after the operation plan is just notified and the power generation power of the mega solar power plant 26 decreases by 50%, the deficient 50% of the power is shared according to the proportion of the power target value calculated at the time of making the operation plan. Therefore, in a case where, for example, the power target values of the plurality of storage batteries 40 are calculated in a manner that the SOCs become substantially zero at the same time at the time of making the operation plan, the deficient 50% of the power is distributed in proportion according to the proportion of the power target value, so it is possible to control in a manner that the SOCs become substantially zero at the same time.

[0482] Further, in the embodiments 1 and 2, the structure in which the virtual synchronous generator control is installed to the power conversion device 41 for the storage battery 40 is described, but is not limited thereto, and, for example, even in a structure in which the virtual synchronous generator control is installed to a wind power generator or the like energy generating device, the same effect is of course exerted. In particular, the wind power generator rotates the motor with a propeller, so the generator has an inertial force, and the same effect is of course exerted.

[0483] In addition, in the embodiments 1 and 2, the structure in which a plurality of large-capacity storage batteries like the storage battery 40 are installed to the power distribution system 24 is described, but it is also possible to install the virtual synchronous generator control to the power conversion device of the household storage battery or the power conversion device for an electric automobile, and to implement the same control as the control performed with the CEMS 31. In this case, the power conversion devices connected to the power distribution system 24 can be in the order of several hundred. Also, even if a large capacity like the storage battery 40 (for example, several hundred kW to several MW) and a household storage battery (several kW) are disposed as the storage battery capacity, the same effect is exerted.

[0484] In addition, the power conversion device 41 for the storage battery 40 is explained in Embodiments 1 and 2, but is not limited thereto, and the same effects can be obtained by configuring to generate the control parameter for the virtual synchronous generator control using the above-described method with respect to a structure in which a virtual synchronous generator control is installed in a system in which a static inverter controlled as a voltage source, such as a power conversion device (for example, a solar cell (including a household solar cell), a wind power generator, and a power generation power of a fuel cell) is supplied to the power distribution system 24.

[0485] Furthermore, a vehicle-mounted storage battery of an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV), or a fuel cell vehicle (FCV), or the like can also be used.

[0486] In addition, in Embodiments 1 and 2, a single-phase alternating current is explained for the sake of simplicity of explanation, or a three-phase alternating current is explained in Figures 21 to 31 The operation is explained using the power conversion device 41 having an inverter capacity of several kW in the explanation of Embodiments 1 and 2, but is not limited thereto.

[0487] In addition, the distributed power management device is applied to the power distribution system in Embodiments 1 and 2, but is not limited thereto, and the same effects can be obtained even if the technology of the present disclosure is applied to a microgrid of a power transmission system or an independent system.

[0488] Furthermore, a single-phase alternating current or a single-phase three-wire alternating current can also be used in Embodiments 1 and 2. Furthermore, even in a structure in which a power conversion device (three-phase alternating current) for a system storage battery and a household storage battery system (single-phase alternating current) are mixed, the same effects can be obtained by configuring to generate the control parameter for the virtual synchronous generator control using the above-described method.

[0489] In addition, in Embodiments 1 and 2, a structure in which the capacity of the static inverter and the power target value are used to generate the control parameter when generating the control parameter for the virtual synchronous generator control with respect to the static inverter within the power conversion device 41 is explained, but is not limited thereto. For example, in a case in which the capacity ratio of the storage battery capacity of the storage battery 40a with respect to the capacity of the static inverter within the power conversion device 41a is 2 times, the capacity ratio of the storage battery capacity of the storage battery 40b with respect to the capacity of the static inverter within the power conversion device 41b is 3 times, or the like, in which the capacity ratio of the storage battery with respect to the static inverter differs from each other, the same effects can be obtained by configuring to generate the operation plan (power target value) considering the capacity ratio or considering the above-described capacity ratio when generating the control parameter.

[0490] In Embodiment 2, the structure in which the system information and the slope information of the ΔP / ΔF characteristic are transmitted in addition to the electric power target value in a manner capable of generating the control parameter within the electric power conversion device 41 is explained, but the information to be transmitted is not limited thereto, and the same effect can be obtained by configuring to transmit the information capable of generating the control parameter within the electric power conversion device 41 from the CEMS 31.

[0491] In Embodiments 1 and 2, the structure of the virtual synchronous generator model ( Figure 5 ) built-in is explained, but is not limited thereto, and the structure in which the relationship between the braking coefficient Dg and the system frequency ( Figure 19 ) is stored as table data in correspondence with a plurality of speed adjustment rates Kgd respectively, and the combination of the speed adjustment rate Kgd and the braking coefficient Dg that are substantially in agreement with the slope of the ΔP / ΔF characteristic is retrieved in accordance with the ΔFmax information, or the relationship between the speed adjustment rate Kgd and the system frequency ( Figure 18 ) is stored as table data in correspondence with a plurality of braking coefficients Dg respectively, and the combination of the speed adjustment rate Kgd and the braking coefficient Dg that are substantially in agreement with the slope of the ΔP / ΔF characteristic is retrieved in accordance with the ΔFmax information. For example, other methods such as a virtual synchronous generator control circuit built-in in a formula model can be adopted, of course.

[0492] Further, in Embodiments 1 and 2, the structure in which the ΔP / ΔF characteristic is calculated at the time of generating the control parameter is explained, but is not limited thereto, and for example, the structure in which the distribution system model (digital twin) of the substation 20 and the like is installed within the CEMS 31 to generate the control parameter in a manner that optimally acts in the use example assumed using the distribution system model can be provided. Further, the structure in which the AI is installed and the AI is used to generate the control parameter can be configured.

[0493] Further, in Embodiments 1 and 2, the communication cycle between the CEMS 31 and the DSO 21 is configured to be 30 minutes, and the communication cycle between the CEMS 31 and the electric power conversion device 41 is configured to be 5 minutes, but is not limited thereto. For example, the communication cycle between the CEMS 31 and the electric power conversion device 41 can be configured to be 1 minute.

[0494] Further, in Embodiments 1 and 2, the governor model within the governor control circuit 833 ( Figure 14 ) is modeled as a first-order delay system, but is not limited thereto, and the governor model can be configured from a second-order delay system or an LPF (Low Pass Filter), and the like.

[0495] Moreover, in Embodiments 1 and 2, the mass system operation circuit 837( Figure 14 ) is modeled with an integrator and a feedback loop, but is not limited thereto, and can be modeled with, for example, a first-order delay system, a second-order delay system, and an LPF. Moreover, in Embodiments 1 and 2, the VQ control widely used in virtual synchronous generator control is omitted for the sake of simplicity of explanation, but the same effects can be obtained even when the present disclosure is employed in a power conversion device in which the VQ control is installed as virtual synchronous generator control. Moreover, the structure of the mass system operation circuit 837( Figure 14 ) is not limited to the circuit shown in Figure 16 .

[0496] Description of Modified Examples

[0497] In Embodiments 1 and 2, for the sake of easy understanding of the explanation, the case where the control circuit in the power conversion device 27 and the power conversion device 41 is configured as the structure shown in Figures 6 to 16 , and the hardware shown in Figures 3 to 5 is configured as the CEMS 31 is described, but the same control functions can be achieved even when the functions of each module or a part of the modules are configured by software installed on a CPU (Central Processing Unit). Alternatively, with respect to at least a part of the modules, the same control functions can be achieved by division of the functions of software and hardware.

[0498] Furthermore, with respect to the above-described embodiments and modified examples, the structures described in the embodiments can be appropriately combined within a range in which no incongruity or contradiction occurs, including combinations not mentioned in the specification, from the time of filing of the application.

[0499] It should be understood that the embodiments of the present disclosure are merely illustrative and are not restrictive. The scope of the present disclosure is not the above-described description but is shown by the claims, and is intended to include all modifications within the meaning and range equivalent to the claims.

[0500] Explanation of Symbols

[0501] 11: communication circuit; 12: storage circuit; 13: control parameter generation circuit; 14: operation plan making circuit; 15: transmission data generation circuit; 16: control circuit; 20: substation; 21: distribution automation system (DSO); 22, 201, 206, 210, 401, 406, 410: voltage meter; 23: automatic voltage regulator (SVR); 24: distribution system; 25: communication line; 26: megawatt solar power plant; 27: power conversion device for megawatt solar power plant; 28: switch; 29: impedance; 30a, 30b: synchronous generator; 31: CEMS; 40, 40a to 40c: storage battery for system; 41, 41a to 40c: power conversion device for storage battery; 51: MPPT control circuit; 52: voltage control circuit; 53: first switching circuit; 54: fifth control circuit; 61: phase detection circuit; 62: first sine wave generation circuit; 63, 66, 101, 832, 836, 852: subtracter; 64: first PI control circuit; 65, 91, 103: multiplier; 67: sixth control circuit; 68: second PI control circuit; 69: first PWM converter; 71: charge control circuit; 72: discharge control circuit; 73: second switching circuit; 74: seventh control circuit; 81: AC frequency detection circuit; 82: effective power calculation circuit; 83: virtual synchronous generator control circuit; 84: inverter current control circuit; 85: inverter voltage control circuit; 86: third switching circuit; 87: eighth control circuit; 92: primary delay system model; 93: limiter circuit; 102: integrator; 104: divider; 105, 835: adder; 106: phase calculation circuit; 100a to 100d: city and town; 110: factory; 112: building; 113: apartment; 141: storage battery operation plan making circuit; 142: power generation power prediction circuit; 143: consumption power prediction circuit; 144: storage battery operation plan correction circuit; 135, 145, 146: management circuit; 131: reference ΔP / ΔF characteristic calculation circuit; 132: ΔP / ΔF characteristic calculation circuit; 133: control parameter generation circuit; 134: virtual synchronous generator model; 136: control circuit; 202, 207, 211, 402, 407, 411: current meter; 203: first DC / DC converter; 204: first control circuit; 205, 405: direct current bus; 208: first DC / AC converter; 209: second control circuit; 212, 412: communication I / F; 403: second DC / DC converter; 404: second control circuit; 408: second DC / AC converter; 409: fourth control circuit; 810: phase detection circuit; 811: frequency detection circuit; 812: second sine wave generation circuit; 833: governor control circuit; 837: mass point system operation circuit; 851: third sine wave generation circuit;853: third PI control circuit; 854: second PWM converter; 600: load.

Claims

1. A distributed power source management device that manages a plurality of distributed power sources interconnected with a power distribution system, wherein the plurality of distributed power sources each have a static inverter installed with a virtual synchronous generator control, the distributed power source management device is provided with: a communication circuit that communicates between the plurality of distributed power sources; an operation plan making circuit that generates a power target value of each of the plurality of distributed power sources based on information received by the communication circuit and capacities of the plurality of distributed power sources; and a control parameter generating circuit that generates a control parameter for the virtual synchronous generator control in each of the distributed power sources or information required for generation of the control parameter, the communication circuit is configured to receive measurement information of each of the distributed power sources and transmit a control instruction to each of the distributed power sources, the control parameter generating circuit generates the control parameter or the information required for generation of the control parameter based on the information received by the communication circuit, the capacities of the plurality of distributed power sources, and the power target value of each of the distributed power sources, and outputs the generated control parameter or the information required for generation of the control parameter to each of the distributed power sources as the control instruction via the communication circuit.

2. The distributed power source management device according to claim 1, wherein the control parameter generating circuit generates the control parameter based on information indicating a capacity of the static inverter of each of the distributed power sources and the power target value of each of the distributed power sources generated by the operation plan making circuit.

3. The distributed power source management device according to claim 1, wherein the control parameter generating circuit generates the control parameter based on the power target value of each of the distributed power sources generated by the operation plan making circuit and information for managing the power distribution system.

4. The distributed power source management device according to any one of claims 1 to 3, wherein the control parameter generating circuit generates a reference ΔP / ΔF characteristic indicating a relationship between a differential frequency and a differential power when half of a capacity of the static inverter is set as a power target value, wherein the differential frequency is a deviation of a system frequency from a reference frequency, and the differential power is a deviation of an output power of the static inverter from a power target value, the control parameter generating circuit generates a ΔP / ΔF characteristic of each of the distributed power sources using a ratio of the power target value generated by the operation plan making circuit to half of the capacity of the static inverter, based on the generated reference ΔP / ΔF characteristic.

5. The distributed power source management device according to claim 4, wherein the control parameter generating circuit calculates a slope of the ΔP / ΔF characteristic of each of the distributed power sources based on the slope of the reference ΔP / ΔF characteristic and the ratio of the power target value generated by the operation plan making circuit to half of the capacity of the static inverter.

6. The distributed power source management device according to claim 5, wherein ​ ​ The control parameter generating circuit calculates a maximum value of the differential frequency corresponding to a maximum value of the differential power in the ΔP / ΔF characteristics of each of the distributed power sources, and generates the control parameter based on the maximum value of the differential frequency.

7. The distributed power source management device according to any one of claims 1 to 3, wherein Each of the distributed power sources includes a control circuit that executes the virtual synchronous generator control, The control circuit has a governor control circuit that simulates a governor function of a synchronous generator, and a mass system operation circuit that simulates a swing equation of the synchronous generator, The control parameter generating circuit generates at least one of a gain of the governor control circuit and a damping coefficient of the mass system operation circuit as the control parameter.

8. The distributed power source management device according to claim 7, wherein The communication circuit notifies, for each of the distributed power sources, at least one of the gain of the governor control circuit and the damping coefficient of the mass system operation circuit and the power target value generated by the operation plan making circuit.

9. The distributed power source management device according to claim 4, wherein The communication circuit notifies, for each of the distributed power sources, the power target value generated by the operation plan making circuit and the ΔP / ΔF characteristics of each of the distributed power sources or information used when generating the ΔP / ΔF characteristics, which are generated by the control parameter generating circuit.

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