JP2019122150A - Power system and storage battery power conditioner - Google Patents

Abstract

To provide a power system and power conditioner that suppress sudden change in output power.SOLUTION: A power system of the present disclosure comprises: a power conditioner PCSto which power is input from a solar battery; a power conditioner PCSfor controlling charge/discharge of a storage battery; a power line 90 connected to a power system; and a centralized management device MC1 for managing the power conditioner PCSand the PCS. The power conditioner PCScomprises a C rate setting unit 32 for setting a characteristic value (C rate) for regulating input/output power at the time of the charge/discharge of the storage battery. The characteristic value set by the C rate setting unit 32, when being changed to a new set value, a designated value, changes in stages from the current set value to the designated value.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a grid-connected power system, and more particularly to a power system that controls regulated power to target power. The present disclosure also relates to a storage battery power conditioner included in the power system.

  BACKGROUND In recent years, power generation systems using renewable energy have become widespread. As an example, there is a solar power generation system using sunlight. The solar power generation system includes a solar cell and a power conditioner. The solar cell generates direct current power, and the power conditioner converts the direct current power into alternating current power. The converted AC power is supplied to the power system. Solar power generation systems range from small-scale ones for general household use to large-scale ones such as mega solar systems. In such a solar power generation system, output fluctuation occurs due to weather fluctuation and the like. In order to suppress this output fluctuation, it may be provided with the power conditioner which connected the storage battery and the storage battery.

  For example, Patent Document 1 includes a solar cell, a first power conditioner connecting the solar cell, a storage battery, a second power conditioner connecting the storage battery, a first power conditioner, and a second power conditioner. A solar power generation system is disclosed that includes a centralized management device to manage. In this conventional photovoltaic power generation system, the centralized management device calculates an index for controlling the predetermined adjustment target power to the target power, and the first power conditioner and the second power conditioner dispersely using the index. Control the output power. In such a solar power generation system, characteristic values for limiting input / output power at the time of charge and discharge of the storage battery are set in the second power conditioner. As this characteristic value, for example, there is a C rate. The C rate is a relative ratio of the current during charging or discharging to the total capacity of the storage battery, and is 1 C when charging or discharging the entire capacity of the storage battery in one hour.

International Publication No. 2017/150376

  In the conventional solar power generation system, the output power of the whole may change rapidly. Such a sudden change in output power may occur, for example, when the C rate set in the second power conditioner is changed, which causes an adverse effect on the power system. Therefore, there is still room for improvement in the conventional solar power generation system.

  An electric power system according to the present disclosure has been conceived in view of the above circumstances, and an object thereof is to provide an electric power system and a storage battery power conditioner which can suppress sudden change in output power of the entire system. is there.

  A power system provided by the first aspect of the present disclosure includes a power control device to which power is input from a power generation device, a storage battery power conditioner for controlling charging and discharging of a storage battery, the power control device, and the storage battery power conditioner. And a central control unit for managing the power control unit and the storage battery power conditioner, and the storage battery power conditioner is configured to charge the storage battery. A setting means is provided for setting a characteristic value for limiting input / output power at the time of discharge, and when the characteristic value set by the setting means is changed to a specified value which is a new setting value, The present invention is characterized in that it is gradually changed from the currently set current value to the specified value. According to this configuration, since the characteristic value set in the storage battery power conditioner is changed stepwise, the restriction of input / output power at the time of charging / discharging of the storage battery is changed stepwise. Since the restriction of input / output power at the time of charge / discharge of the storage battery is the limitation of the output power of the storage battery power conditioner, depending on the difference between the current value and the designated value when changing the characteristic value, Input and output power may change rapidly. However, since the output power of the storage battery power conditioner is gradually changed by changing the characteristic value in stages, it is possible to suppress a sudden change in the output power of the storage battery power conditioner. Therefore, when changing the characteristic value in the storage battery power conditioner, it is possible to suppress a sudden change in the output power of the entire power system.

  In a preferred embodiment of the power system, the centralized management device comprises designation means for transmitting the designated value to the storage battery power conditioner, and the setting means is based on the current value according to the centralized management device. The characteristic value is changed stepwise until the received designated value. According to this configuration, the storage battery power conditioner can gradually change the set characteristic value when instructed by the centralized management device to change the setting value of the characteristic value.

  In a preferred embodiment of the power system, the storage battery power conditioner further includes connection determination means for determining whether or not the battery is connected to the power line, and the setting means is connected by the connection determination means. When it is determined that the characteristic value is not set, the characteristic value is set to a predetermined value, and when it is determined that the characteristic value is connected, the characteristic value is changed to the designated value. In the power system, when the storage battery power conditioner is not connected to the power line but is connected to the power line, the output power of the storage battery power conditioner changes instantaneously, and the output power of the entire power system suddenly changes There is something to do. According to this configuration, when the storage battery power conditioner is not connected to the power line but is connected to the power line, the setting value changes the characteristic value stepwise from the predetermined value to the designated value. Thereby, since the restriction of the input / output power at the time of charge and discharge of the storage battery according to the characteristic value is changed stepwise, the output power of the storage battery power conditioner is gradually changed. Therefore, sudden changes in the output power of the entire power system can be suppressed.

  In a preferred embodiment of the power system, the characteristic value is a C rate indicating a relative ratio of input / output current at charging / discharging to the total capacity of the storage battery. According to this configuration, the input / output current is limited by the setting of the C rate, so that the input / output power at the time of charge and discharge of the storage battery can be limited.

  In a preferred embodiment of the power system, the centralized management device calculates an index for controlling the power to be adjusted to a target power, and each of the power control device and the storage battery power conditioner controls the index. Control the individual output power based on the optimization problem used. According to this configuration, each of the power control device and the storage battery power conditioner controls the individual output power in a distributed manner based on the index calculated by the central management device. Thus, the power system can control the adjustment target power to the target power.

  In a preferred embodiment of the power system, the characteristic value is used as a constraint in the optimization problem of the storage battery power conditioner. According to this configuration, the output power of the storage battery power conditioner can be limited by the characteristic value.

  A storage battery power conditioner provided by the second aspect of the present disclosure is a storage battery power conditioner connected to a power line connected to a power system and controlling input / output power during charging / discharging of the storage battery, Target power calculation means for calculating an individual target power which is a target value of output power of the storage battery power conditioner, output control means for controlling an individual output power so as to become the individual target power, charge and discharge of the storage battery Setting means for setting a characteristic value for limiting input / output power of the device, and the setting means is currently set when changing the characteristic value to a specified value which is a new setting value. The present invention is characterized in that it is changed stepwise from the current value to the specified value. According to this configuration, since the characteristic value set in the storage battery power conditioner changes stepwise, the restriction of the input / output current at the time of charging / discharging of the storage battery changes stepwise. Since the restriction of input / output power at the time of charge / discharge of the storage battery is the limitation of the output power of the storage battery power conditioner, depending on the difference between the current value and the designated value when changing the characteristic value, The output power may change rapidly. However, when the characteristic value changes stepwise, the output power of the storage battery power conditioner gradually changes, so that the output power of the storage battery power conditioner can be suppressed from being rapidly changed. Therefore, when changing the characteristic value in the storage battery power conditioner, it is possible to suppress a sudden change in the output power of the entire power system.

  In a preferred embodiment of the storage battery power conditioner, receiving means for receiving an indicator for controlling input / output power at the time of charging and discharging of the storage battery, which is transmitted from a centralized management device that manages the storage battery power conditioner. The target power calculation means calculates the individual target power based on an optimization problem using the index. According to this configuration, the storage battery power conditioner can control the individual output power based on the index.

  According to the power system of the present disclosure, the characteristic value set in the storage battery power conditioner is gradually changed from the current set value to the new set value when the change to the new set value is performed. Thereby, it can suppress that the output electric power of the whole solar energy power generation system changes rapidly. Therefore, the adverse effect on the power system can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the solar energy power generation system which concerns on 1st Embodiment. It is a figure which shows the function structure regarding electric power control of the solar energy power generation system which concerns on 1st Embodiment. It is a figure which shows the relationship of a control parameter | index and separate output electric power in the power conditioner to which the solar cell was connected. It is a figure which shows the relationship between a control parameter | index and separate output electric power in the power conditioner to which the storage battery was connected. It is a figure which shows the verification result by simulation which concerns on 1st Embodiment. It is a figure which shows the function structure regarding electric power control of the solar energy power generation system which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 1) by simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 2) by simulation which concerns on 2nd Embodiment. It is a figure which shows the whole structure of the solar energy power generation system which concerns on 3rd Embodiment. It is a figure which shows the function structure regarding electric power control of the solar energy power generation system which concerns on 3rd Embodiment.

Hereinafter, an embodiment of a power system of the present disclosure will be described by taking a grid-connected photovoltaic power generation system connected to a power system as an example. FIG. 1 shows the overall configuration of a solar photovoltaic system PVS1 according to the first embodiment. As shown in FIG. 1, the solar power generation system PVS1 includes a power line 90, a power load L, a plurality of solar cells SP _i (i = 1, 2,..., N; n is a positive integer), a plurality of powers A conditioner PCS _PVi , a plurality of storage batteries B _k (k = 1, 2,..., M; m is a positive integer), a plurality of power conditioners PCS _Bk , and a central management device MC1 are provided. In the following description, when power is output from the solar power generation system PVS1 to the power grid A, that is, when reverse power flow is present, the interconnection point between the solar power generation system PVS1 and the power grid A The power at is assumed to be a positive value. On the other hand, when electric power is output from the power system A to the solar power generation system PVS1, the electric power at the interconnection point has a negative value.

The power line 90 is for constructing a power grid in the solar power generation system PVS1. Power line 90 is connected to power system A via an interconnection point. In addition, a power load L, a plurality of power conditioners PCS _PVi , and a plurality of power conditioners PCS _Bk are connected to the power line 90.

The power load L consumes the supplied power. Power load L is supplied with power from power system A and power conditioners PCS _PVi and PCS _Bk via power line 90. As an example of the power load L, there is a factory or a general household. The solar power generation system PVS1 may not have the power load L.

Each of the plurality of solar cells SP _i converts solar energy into electrical energy. Each solar cell SP _i includes a plurality of solar cell panels connected in series and in parallel. The solar battery panel is, for example, a solar battery panel in which a plurality of solar battery cells made of a semiconductor such as silicon are connected and protected by a resin, tempered glass or the like so that it can be used outdoors. Each solar cell SP _i outputs the generated electric power (DC power) to each power conditioner PCS _PVi . In each solar cell SP _i , the maximum amount of power that can be generated is taken as the generated amount P _i ^SP of the solar cell SP _i . The solar cell SP _i corresponds to the “power generation device” of the present invention.

Each of the plurality of power conditioners PCS _PVi, converts power each solar SP _i is power generation (DC power) into AC power, and outputs. Each power conditioner PSC _PVi performs maximum power point tracking control (MPPT control) so that the power generated by each solar cell SP _i can be maximally output. In the present embodiment, the power conditioner PCS _PVi operates in the MPPT control with such responsiveness that the output changes in a cycle of 1 sec, for example. Note that this cycle is not limited to 1 sec. Each power conditioner PCS _PVi includes an inverter circuit, a transformer, a control circuit, and the like. In each power conditioner PCS _PVi , the inverter circuit converts DC power input from the solar cell SP _i into AC power synchronized with the power system A. The transformer boosts (or steps down) AC voltage output from the inverter circuit. The control circuit controls an inverter circuit and the like. In addition, each power conditioner PCS _PVi is not limited to what was comprised as mentioned above. The power conditioner PCS _PVi corresponds to the "power control device" of the present invention.

Each of the plurality of storage batteries B _k is a battery capable of performing repeated charging and discharging. The storage battery B _k is, for example, a secondary battery such as a lithium ion battery, a nickel hydrogen battery, a nickel cadmium battery, or a lead storage battery. Also, a capacitor such as an electric double layer capacitor may be used. Battery B _k is to discharge accumulated power and supplies DC power to the power conditioner PCS _Bk.

The plurality of power conditioners PCS _Bk convert DC power input from the storage battery B _k into AC power and output the AC power. Furthermore, each power conditioner PCS _Bk converts AC power input from power system A or each power conditioner PCS _PVi to DC power via power line 90, and supplies the DC power to storage battery B _k. Charge _k . Each power conditioner PCS _Bk controls charging and discharging of each storage battery B _k . Therefore, the power conditioner PCS _Bk functions as a discharge circuit to discharge the charging circuit and the battery B _k to charge the battery B _k. In this embodiment, each power conditioner PCS _Bk, as a characteristic value for limiting the output power at the time of charging and discharging of the storage battery B _k, C rate is set. The C rate in the present embodiment includes the C rate on the charge side and the C rate on the discharge side. The C rate on the charge side is the C rate for the current when charging each storage battery B _k , and will be referred to as the “charge rate” in the following description. The C rate on the discharge side is a C rate with respect to the current when each storage battery B _k discharges, and will be referred to as a "discharge rate" in the following description. That is, the discharge rate and the charge rate are set to each power conditioner PCS _Bk . Power conditioner PCS _Bk corresponds to the "storage battery power conditioner" of the present invention.

Enable power P _PVi ^out output from the power conditioner PCS _PVi, when the reactive power and Q _PVi ^out, the complex power from each power conditioner ^{_{PCS PVi P PVi out + j ·}} Q PVi out is output. Also, assuming that the active power output from each power conditioner PCS _Bk is P _Bk ^out and the reactive power is Q _Bk ^out , the complex power of P _Bk ^out + j · Q _Bk ^out is output from each power conditioner PCS _Bk There is. Therefore, a plurality of power conditioners PCS _PVi, from PCS _Bk, complex power sum ^{_{(Σ i P PVi out + Σ}} k P Bk out) + j (Σ i Q PVi out + Σ k Q Bk out) is outputted. In the present embodiment, the output control of the reactive powers Q _PVi ^out and Q _Bk ^out mainly used for voltage fluctuation suppression at the interconnection point is not particularly considered. That is, the individual output powers controlled by the power conditioners PCS _PVi and PCS _Bk are the active powers P _PVi ^out and P _Bk ^out , respectively. Thus, the individual output power of each power conditioner PCS _PVi and P _PVi ^out, the individual output power of each power conditioner PCS _Bk and P _Bk ^out, when the power consumption P _L of the power load L, the power at the interconnection node P (t) (hereinafter referred to as “connection point power”) is the sum of the individual output powers P _PVi ^out and P _Bk ^{out of the} power conditioners PCS _PVi and PCS _Bk and the power consumption P _L of the power load L ( I _i P _PVi ^out + _{k k} P _Bk ^out- P _L ).

The central management device MC1 centrally manages a plurality of power conditioners PCS _PVi and PCS _Bk . The central management device MC1 transmits and receives various types of information to and from the power conditioners PCS _PVi and PCS _Bk , for example, by wireless communication. Note that wired communication may be used instead of wireless communication.

In the solar power generation system PVS1 configured as described above, the central management device MC1 monitors a predetermined adjustment target power, and the adjustment target power based on the adjustment target power and the target power which is the target value of the adjustment target power. Calculate the index to make the power the target power. Then, the power conditioners PCS _PVi and PCS _Bk perform control in a distributed manner using the index to set the adjustment target power as the target power. The power to be adjusted is the output power of the entire photovoltaic power generation system PVS1. In the present embodiment, the output power of the entire solar power system PVS1 the consumption of the individual output power P _Bk ^out and power load L of the individual output power P _PVi ^out and the power conditioner PCS _Bk of the power conditioner PCS _PVi is the sum of the power P _L. Further, as described above, the interconnection point power P (t) is the consumption of the individual output power P _PVi ^out of each power conditioner PCS _PVi , the consumption of the individual output power P _Bk ^{out of} each power conditioner PCS _Bk , and the power load L is the sum of the power P _L. Therefore, in the present embodiment, a case where the interconnection point power P (t) is used as the adjustment target power will be described. That is, photovoltaic systems PVS1 performs control for linking point power P (t) is the target power P ^C.

Indicators for Specifically, in photovoltaic systems PVS1, the central control device MC1 is to monitor the interconnection point power P (t), to match the interconnection point power P (t) and the target power P ^C Calculate In the present embodiment, a control index pr _PV and a control index pr _B are calculated as the index. The control index pr _PV is information for setting the interconnection point power P (t) to the target power P ^C , and is information for causing each power conditioner PCS _PVi to calculate the individual target power P _PVi ^ref . The individual target power P _PVi ^ref is a target value of the individual output power P _PVi ^out of the power conditioner PCS _PVi . The control index pr _B is information for setting the interconnection point power P (t) to the target power P ^C , and is information for causing each power conditioner PCS _Bk to calculate the individual target power P _Bk ^ref . The control index pr _B is also information for determining how much to charge or discharge the storage battery B _k . The individual target power P _Bk ^ref is a target value of the individual output power P _Bk ^out of the power conditioner PCS _Bk . Then, the central management device MC1 transmits the control index pr _PV to each power conditioner PCS _PVi, and transmits the control index pr _B to each power conditioner PCS _Bk . Each power conditioner PCS _PVi, based on the control indication pr _PV received from the central control device MC1, calculates individual target power P _PVi ^ref, based calculated the individual target power P _PVi ^ref, individual output power P _PVi ^out Control. Each power conditioner PCS _Bk based on the control indication pr _B received from the central control device MC1, calculates individual target power P _Bk ^ref, based calculated the individual target power P _Bk ^ref, individual output power P Control _Bk ^out . Thereby, the grid interconnection point power P (t) to match the target power P ^C.

In the present embodiment, as the target power P ^C, suppression target value, the peak cut target value, the backward flow around the target value, such as the schedule target value is set. These are suitably set according to the various electric power control which solar power generation system PVS1 performs.

The suppression target value is a target value for performing output suppression control to suppress the output power in accordance with the output suppression command instructed from the power company. When the solar power generation system PVS1 performs output suppression control, suppression target value is set as the target power P ^C. In recent years, the number of photovoltaic power generation systems connected to the power system A is increasing, and there is a possibility that the supply of power to the power system A becomes excessive compared to the demand. In order to eliminate the excessive supply state, an electric power company or the like instructs each photovoltaic power generation system to suppress individual output power. Therefore, in accordance with the output suppression commands from the power company, in order to suppress the electric power supplied to the power grid A, it sets a suppression target value as the target power P ^C. As a result, the interconnection point power P (t) is controlled to become the suppression target value. That is, since the interconnection point power P (t) does not exceed the suppression target value, the power supplied to the power system A can be suppressed according to the output suppression command.

The peak cut target value is a target value for performing peak cut control to reduce the peak value of the power (purchased power) supplied from the power system A. If photovoltaic system PVS1 performs peak-cut control, the peak cut target value as the target power P ^C is set. For example, when the photovoltaic power generation system PVS1 includes the power load L, power may be supplied from the power system A to the photovoltaic power generation system PVS1. At this time, power is purchased from a power company, and it is necessary to pay for the electricity by this purchase. When the peak value of purchased power is high, the electricity rate will also be high. Therefore, in order to suppress the peak value of the power purchase power, it sets a peak cut target value as the target power P ^C. Thereby, the interconnection point power P (t) is controlled to be the peak cut target value. That is, since the interconnection point power P (t) does not exceed the peak cut target value, it is possible to suppress the peak value of purchased power.

The reverse power flow avoidance target value is a target value for performing reverse power flow avoidance control that suppresses the occurrence of reverse power flow. If photovoltaic system PVS1 performs reverse flow prevention control, backward flow around the target value as the target power P ^C is set. For example, when the solar power generation system PVS1 is a self-consumption system, reverse power flow is prohibited. Therefore, in order to suppress the occurrence of reverse power flow, as the target power P ^C, sets the reverse power flow around the target value. Thereby, the interconnection point power P (t) is controlled to be the reverse power flow avoidance target value. That is, since the interconnection point power P (t) does not exceed the reverse power flow avoidance target value, reverse power flow can be avoided. In addition, in the solar power generation system PVS1 in which reverse power flow is prohibited, installation of a reverse power relay is required at the connection point with the power system A. The reverse power relay is a type of relay, and when it detects the occurrence of reverse power flow, the photovoltaic power generation system PVS1 is disconnected from the power system A. Therefore, reverse power flow avoidance control can prevent the reverse power relay from operating.

The schedule target value is a target value for performing schedule control for controlling the interconnection point power P (t) to a value freely set for each predetermined time zone. The predetermined time zone is a predetermined period obtained by dividing one day into a plurality of days, and can be set every 48 time zones, for example, when divided into 30 minutes. Note that the predetermined time zone is not limited to the above-described example, and may be divided into time zones such as morning, noon, evening, evening, late night, etc. It may be divided. If photovoltaic system PVS1 performs scheduling control, schedule target value is set as the target power P ^C. As the target power P ^C, by setting the schedule target value, interconnection node power P (t) is controlled to a set schedule target value for each predetermined time period. That is, the interconnection point power P (t) can be controlled to a free value every predetermined time zone.

FIG. 2 shows a functional configuration of a control system related to power control of the solar power generation system PVS1 shown in FIG. In FIG. 2, illustration of the solar cell SP _i and the storage battery B _k is omitted. In addition, only one (power conditioners PCS _PV1 and PCS _B1 ) is described for each of the plurality of power conditioners PCS _PVi and PCS _Bk .

  As shown in FIG. 2, the central management device MC1 includes a target power setting unit 11, an interconnection point power detection unit 12, an index calculation unit 13, a transmission unit 14, and a C rate specification unit 15 as a control system in power control. Contains.

The target power setting unit 11 sets a target value of the interconnection point power P (t). That is, setting the target power P ^C. As described above, the target power P ^C includes a suppression target value, a peak cut target value, a reverse power flow avoidance target value, and a schedule target value, and any one of these is set as the target power P ^C Ru.

When the solar power generation system PVS1 performs output suppression control as power control, the target power setting unit 11 acquires the output command value instructed from the electric power company, and sets the suppression target value based on the acquired output command value to the target power P. Set as ^C. For example, when the output command value to be acquired is a value for specifying the upper limit value of the output power, the output command value is set as the suppression target value. Alternatively, when the output command value to be acquired is the output suppression rate [%], the output suppression rate [%] and the rated output of the entire solar power generation system PVS1 (that is, the sum of the rated outputs of the respective power conditioners PCS _PVi ) based on the sigma _i P _PVi ^lmt, it calculates the upper limit value of the output power, and sets this as the suppression target value. For example, the target power setting unit 11, when acquiring the command is 20% as an output inhibition rate, 80% of the rated output Σ _i P _PVi ^lmt photovoltaic systems PVS1 (= 100-20) the upper limit of the output power Calculated as a value, which is set as a target value for suppression. In addition, it is not limited to what obtains an output command value directly from a power company. For example, the configuration may be such that the user manually inputs an output command value instructed from a power company to a predetermined computer, and the target power setting unit 11 acquires the output command value from the computer. Alternatively, another communication device may be relayed to obtain an output command value instructed from the power company.

If photovoltaic system PVS1 performs peak cut control as power control, a target power setting unit 11 sets a peak cut target value specified by the user as the target power P ^C. As the interconnection point power P (t) is a negative value and smaller, the power supplied from the power system A becomes larger, so the purchased power becomes larger. Since peak cut control is control for suppressing the peak value of purchased power, peak cut control is performed so that purchased power does not exceed the upper limit value designated by the user. Therefore, during peak cut control, the interconnection point power P (t) matches the peak cut target value so that the interconnection point power P (t) does not fall below the peak cut target value where the upper limit value is a negative value. I am doing it. Therefore, the peak cut target value is a negative value.

If photovoltaic system PVS1 performs the backward flow prevention control as power control, a target power setting unit 11 sets the reverse power flow avoidance target value specified by the user as the target power P ^C. Since the reverse power flow occurs when the interconnection point power P (t) is a positive value, the interconnection point power P (t) does not have a positive value in order to suppress the occurrence of the reverse power flow. As long as you keep negative values. Therefore, at the time of reverse power flow avoidance control, the linkage point power P (t) is made to coincide with the reverse power flow avoidance target value so that the linkage point power P (t) becomes a negative value. Therefore, the reverse power flow avoidance target value is a negative value.

If photovoltaic system PVS1 performs scheduling control as power control, a target power setting unit 11 sets a schedule target value specified by the user as the target power P ^C. In schedule control, since the interconnection point power P (t) is controlled to the user's preference value, the schedule target value can be set freely.

Target power setting unit 11 outputs the target power P ^C set in the index calculation unit 13. The target power setting unit 11, when there is no setting of the target power P ^C, transmits the fact to the index calculation unit 13. For example, in such as when and solar SP _i is output to maximize the power generated when no command output suppression power company, there is no setting of the target power P ^C. In the present embodiment, the target power setting unit 11, when there is no setting of the target power P ^C, outputs a numeric -1 to the index calculation unit 13 as the target power P ^C. Incidentally, if transmit no setting of the target power P ^C to the index calculation unit 13, the technique is not limited. For example, the target power setting unit 11 may be configured to transmit the flag information indicating the presence or absence of setting of the target power P ^C to the index calculation unit 13. The flag information includes, for example, if there is no setting of the target power P ^C is "0", a case where there is a setting of the target power P ^C "1". In the case where there is a setting of the target power P ^C (if the flag information is "1") may be configured to transmit the set target power P ^C to the index calculation unit 13 together with the flag information.

  The interconnection point power detection unit 12 detects interconnection point power P (t). Then, the detected interconnection point power P (t) is output to the index calculation unit 13. The interconnection point power detection unit 12 may be configured as a detection device separate from the central management device MC1. In this case, the detection device (connected point power detection unit 12) transmits the detected value of the connected point power P (t) to the central management device MC1 by wireless communication or wired communication.

Index calculating unit 13 calculates an index for the interconnection point power P (t) to the target power P ^C. In the present embodiment, the index calculation unit 13 receives the target power P ^C from the target power setting unit 11 and sets the control index pr _PV , pr _B for setting the interconnection point power P (t) to the target power P ^C. Calculate The index calculation unit 13 calculates control indexes pr _PV and pr _B based on the following equation (1) and equation (2), where Lagrange multiplier is λ, gradient coefficient is ε (> 0), and time is t. However, the index calculation unit 13 as the target power P ^C from the target power setting unit 11, if a numeric value -1 to indicate that there is no setting of the target power P ^C is input, the Lagrange multiplier λ is set to "0" . That is, both control indexes pr _PV and pr _B are calculated as “0”. In the following equation (1), the target power P ^C is as a value which changes with respect to time t, and the target power is described as P ^C (t). The index calculation unit 13 calculates the control indexes pr _PV and pr _B at predetermined time intervals. In the present embodiment, although the predetermined time is 1 [sec], it is not limited to this. The control indicator pr _PV, arithmetic expression for calculating the pr _B is not limited to the following (1) and the following equation (2) may be different arithmetic expression from these.

The transmission unit 14 transmits the control indices pr _PV and pr _B calculated by the index calculation unit 13 to the power conditioners PCS _PVi and PCS _Bk , respectively. Transmitter 14, control index pr _PV by index calculation unit 13, every time the pr _B is calculated, the calculated control index pr _PV, transmits the pr _B. Therefore, in the present embodiment, the control indicators pr _PV and pr _B are transmitted to the power conditioners PCS _PVi and PCS _Bk every 1 [sec].

The C rate designation unit 15 transmits the C rate value (hereinafter referred to as "C rate designated value") to be set to the plurality of power conditioners PCS _Bk to each power conditioner PCS _Bk . For example, when the user performs an operation of specifying a C rate value (hereinafter referred to as a "request value") desired to be set in a plurality of power conditioners PCS _Bk using an operation device (not shown) provided in central management device MC1. The C rate designation unit 15 creates a C rate designation value based on the request value designated by this operation, and transmits the C rate designation value to each of the power conditioners PCS _Bk . In the present embodiment, the C rate specification value created is the same as the value (request value) specified by the user. The user instructs the solar power generation system PVS1 to change the setting value of the C rate by specifying a new value as the request value. The request value may be configured to specify different values for the charge rate and the discharge rate, or may be configured to specify the same value. In the present embodiment, the C rate designation unit 15 periodically transmits the C rate designation value at a predetermined cycle. In addition, it is not limited to this, for example, it may transmit only when C rate designated value is changed. Further, the predetermined cycle is, for example, the same as the calculation interval of the control indexes pr _PV and pr _B , but is not limited thereto. In the present embodiment, the C rate designation unit 15 directly transmits the C rate designation value to each power conditioner PCS _Bk. However, the present invention is not limited to this. For example, transmission via the transmission unit 14 is performed. Alternatively, transmission may be performed via a transmission unit provided in the central management device MC1 separately from the transmission unit 14.

Each power conditioner PCS _PVi includes a receiver 21, a target power calculator 22, and an output controller 23, as a control system related to power control, as shown in FIG.

The receiving unit 21 receives the control index pr _PV transmitted from the central management device MC1. The receiving unit 21 receives the control index pr _PV from the central management device MC1 by wireless communication, for example. Note that wired communication may be used instead of wireless communication.

The target power calculation unit 22 calculates the individual target power P _PVi ^ref of the own device (power conditioner PCS _PVi ) based on the control index pr _PV received by the reception unit 21. Specifically, the target power calculation unit 22 calculates the individual target power P _PVi ^ref by solving the constrained optimization problem shown in the following equation (3). The following equation (3a) in the following equation (3) indicates an evaluation function in the optimization problem. Further, the following equation (3b) and the following equation (3c) in the following equation (3) indicate constraints in the optimization problem. Under the constraint conditions, the following equation (3b) is a constraint due to the rated output of each power conditioner PCS _PVi , and the following equation (3c) is an output current constraint of each power conditioner PCS _PVi . Note that, instead of the output current restriction of each power conditioner PCS _PVi shown in the following equation (3c), the rated capacity restriction of the power conditioner PCS _PVi shown in the following equation (3d) may be used. In addition, in the case where the index calculation unit 13 calculates the control indexes pr _PV and pr _B by an arithmetic expression different from the expression (1) and the expression (2), the constraint set in the target power calculation unit 22 The attached optimization problem may be changed based on the different arithmetic expressions.

In the equation (3a), w _PVi represents a weight related to the effective power suppression of the power conditioner PCS _PVi , which is a design value. Pφ _i is a design value indicating a design parameter (hereinafter, referred to as “priority parameter”) indicating whether to prioritize the suppression of the individual output power P _PVi ^out of the power conditioner PCS _PVi . When the priority parameter Pφ _i is reduced, the charge amount of the storage battery B _k is reduced, and the individual output power P _PVi ^out is easily suppressed. On the other hand, when the priority parameter Pφ _i is increased, the charge amount of the storage battery B _k is increased, and it becomes difficult to suppress the individual output power P _PVi ^out . Therefore, it can be said that priority parameter Pφ _i is a design parameter indicating whether to prioritize charging of storage battery B _k . In addition, this priority parameter P.PHI _i, the output limit according to the rated output of the power conditioner PCS _PVi separately, considered as pseudo output limits of the individual output power P _PVi ^out of the power conditioner PCS _PVi is set Be Therefore, the priority parameter Pφ _i can be said to be a pseudo effective output limit. The weight w _PVi and the priority parameter Pφ _i can be changed by the user.

In the above (3b) equation, P _PVi ^lmt represents the rated output of the power conditioner PCS _PVi (output limit). Therefore, the (3b) expression individual target power P _PVi ^ref that is calculated is limited not to exceed the rated output P _PVi ^lmt.

In the above (3c) formula, Q _PVi the reactive power of the power conditioner PCS _PVi, S _PVi ^d is printable maximum apparent power of the power conditioner PCS _PVi, V ₀ is the reference of the linking point in time of design The voltage, V _PVi , represents the voltage at the interconnection point in each power conditioner PCS _PVi .

In the present embodiment, the weight w _PVi (refer to the above equation (3a)) regarding the active power suppression of each power conditioner PCS _PVi uses a value calculated by the following equation (4). In the following equation (4), pr _PV ^lmt indicates the control index limit. The control index limit pr _PV ^lmt is controlled indication of when to 0 individual output power P _PVi ^out, that is, a control indicator of when 100% suppress individual output power P _PVi ^out. Also, P _PVi ^lmt is a rated output of each power conditioner PCS _PVi. Instead of the rated output P _PVi ^lmt of the power conditioner PCS _PVi, it may be used pseudo effective output limit P.PHI _i. That is, a value calculated by the following equation (4 ') may be used. _{Alternatively} , in the plurality of power conditioners PCS _PVi , weights w _PVi may all be used for the same active power suppression.
w _PVi = pr _PV ^lmt / (2 x P _PVi ^lmt ) (4)
w _PVi = pr _PV ^lmt / (2 x Pφ _i ) (4 ')

FIG. 3 shows the relationship between the control index pr _PV and the individual output power P _PVi ^out when using the weight w _PVi related to the active power suppression of each power conditioner PCS _PVi as described above. Incidentally, in FIG. 3 shows for each of the three power conditioner PCS _PVi the rated output P _PVi ^lmt are different from each other. In the present embodiment, the individual output power P _PVi ^out is controlled to become the individual target power P _PVi ^ref calculated by the target power calculation unit 22, so the figure shows the control index pr _PV and the individual target power. It can be said that the relationship with P _PVi ^ref is shown. In FIG. 3, the control index limit pr _PV ^lmt is ^set to 100. In Figure 3, shows the rated output P _PVi ^lmt is 500kW solid, those rated output P _PVi ^lmt is 250kW dashed rated output P _PVi ^lmt is those 100kW by a dashed line.

As shown in FIG. 3, each time the control index pr _PV is 20 rises between 0 and 100 (control index limit pr _PV ^lmt), when the rated output P _PVi ^lmt is 500kW 100 kW, the rated output P _PVi ^lmt 250 kW for 50 kW, the rated output P _PVi ^lmt is reduced by 20kW for 100 kW. This would have reduced by 20% of the rated output P _PVi ^lmt of the power conditioner PCS _PVi. That is, the individual output power P _PVi ^out is suppressed at a ratio to the rated output P _PVi ^lmt of each power conditioner PCS _PVi . In each of the power conditioners PCS _PVi , when the control index pr _PV is the control index limit pr _PV ^lmt , the individual output power P _PVi ^out is zero. That is, 100% suppression. Further, when the control indicator pr _PV is zero, the individual output power P _PVi ^out has become the rated output P _PVi ^lmt. That is, the power that can be output as much as possible is output. Then, as shown in FIG. 3, the individual output power P _PVi ^{out of} each power conditioner PCS _PVi linearly changes between the control index pr _PV from 0 and the control index limit pr _PV ^lmt (100). . Each power conditioner PCS _PVi, since you can not output more power than its rated output P _PVi ^lmt, when control index pr _PV is a negative value, as shown in FIG. 3, a constant value (the rated output P It has become a _PVi ^lmt). From the above, in setting the weight w _PVi about active power suppression, by using the equation (4), with the change in control index pr _PV, as a percentage of the rated output P _PVi ^lmt of the power conditioner PCS _PVi The individual output power P _PVi ^out can be suppressed. Therefore, a plurality of power conditioners PCS _PVi, be different their rated output P _PVi ^lmt, when the control indicator pr _PV is the control index limit pr _PV ^lmt, the output of the individual output power P _PVi ^out 100% It can be suppressed. In the case of using the same value as the weight w _PVi about effective power restriction, even with different rated output P _PVi ^lmt of the power conditioner PCS _PVi, individual output power P _PVi ^out by the same amount uniformly decreases It can be configured as

The output control unit 23 controls the inverter circuit to control the individual output power P _PVi ^out . The output control unit 23 sets the individual output power P _PVi ^out to the individual target power P _{PV i} ^ref calculated by the target power calculation unit 22.

As shown in FIG. 2, each power conditioner PCS _Bk includes a receiver 31, a C rate setting unit 32, a target power calculation unit 33, and an output control unit 34 as a control system related to power control.

The receiving unit 31 is configured in the same manner as the receiving unit 21 and receives the control index pr _B transmitted from the central management device MC1.

The C rate setting unit 32 receives the C rate designation value transmitted from the central management device MC1, and sets the C rate based on the received C rate designation value. Specifically, the C rate setting unit 32 sets the C rate by setting the C rate setting value of the own device (power conditioner PCS _Bk ) to the C rate designated value. In the present embodiment, the C rate setting unit 32 directly receives the C rate designation value from the central management device MC1. However, the present invention is not limited to this. Alternatively, it may be received via the receiving unit provided in each power conditioner PCS _Bk separately from the receiving unit 31.

In the present embodiment, in each power conditioner PCS _Bk , the C rate designation value received from the central management device MC1 and the C rate setting value at the time of receiving the C rate designation value (hereinafter, “reception setting value”) When the C rate setting unit 32 changes the setting value of the C rate (if the setting value at reception is equal to the designated value of the C rate, the setting value of the C rate is not changed). At this time, the C rate setting value is changed stepwise from the reception setting value to the C rate designation value at one time by the C rate setting unit 32. Specifically, when the reception setting value and the C rate specification value are different, the C rate setting unit 32 previously sets the C rate setting value from the reception setting value to the C rate specification value in a predetermined update cycle. Change by the set unit update amount. The update period is a period for changing the setting value of the C rate, and the update period in this embodiment is the same as the calculation period (1 sec) of the control indicators pr _PV and pr _B by the centralized management device MC1. Note that they may be different. The unit update amount is an amount to be changed for each update cycle, and is an amount to be changed once. In the present embodiment, the unit update amount is 0.05C. Therefore, in the present embodiment, the C rate setting unit 32 changes over 20 seconds from the reception set value to the C rate designation value, for example, when the reception set value is 0 C and the C rate designation value is 1 C. . The update cycle and unit update amount are not limited to the above values, and the time required to change the C rate setting value from 0 C to the maximum value is within the range of 2 sec to 30 min (preferably, 10 sec to 60 sec). It should be set appropriately so that However, it is desirable that the update cycle be in the range of 1 sec to 10 sec, and the unit update amount be in the range of 0.01 C to 0.1 C.

The target power calculation unit 33 calculates the individual target power P _Bk ^ref of the own device (power conditioner PCS _Bk ) based on the control index pr _B received by the reception unit 31. Specifically, the target power calculation unit 33 calculates the individual target power P _Bk ^ref by solving the optimization problem shown in the following equation (5). The following equation (5a) in the following equation (5) indicates an evaluation function in the optimization problem. Further, the following equations (5b) to (5e) in the following equation (5) indicate constraints in the optimization problem. In the constraint condition, the following equation (5b) is a constraint by the rated output of each power conditioner PCS _Bk , the following equation (5c) is a C rate constraint of the storage battery B _k , and the following equation (5d) is each storage battery B _{The following} equation (5e) is an output current constraint of each power conditioner PCS _Bk . Instead of the output current restriction of each power conditioner PCS _Bk shown in the following equation (5e), the rated capacity restriction of power conditioner PCS _Bk shown in the following equation (5f) may be used. In addition, in the case where the index calculation unit 13 calculates the control indexes pr _PV and pr _B by an arithmetic expression different from the expression (1) and the expression (2), the constraint set in the target power calculation unit 33 The attached optimization problem may be changed based on the different arithmetic expressions.

In the equation (5a), w _Bk represents a weight related to the active power of the power conditioner PCS _Bk . The weight w _Bk can be set by the user. w _SOCk represents a weight according to SOC (States Of Charge) of the storage battery B _k . The weight w _SOCk is calculated by the following equation (6). In the following formula (6), A _SOC is the weight w _SOCK offset, K _SOC is the weight w _SOCK gain, s is the weight w _SOCK ON / OFF switch (e.g., 0 1, when off when on), SOC _k represents the current SOC of the storage battery B _k , and SOC _d represents the reference SOC.

In the above equation (5b), P _Bk ^lmt represents the rated output (output limit) of each power conditioner PCS _Bk . Therefore, the above equation (5b) limits the calculated individual target power P _Bk ^ref not to exceed the rated output P _Bk ^lmt .

In the above equation (5c), P _SMk ^lmt represents the charge rated output of storage battery B _k , and the charge rate is C _rate ^M, and the rated capacity of storage battery B _k is WH _S ^lmt , −C _rate It is obtained by ^M × WH _S ^lmt . The charge rated output P _SMk ^lmt of the storage battery B _k takes into account the storage battery charge amount correction according to the SOC shown in the following equation (7), where the correction start SOC is SOC _C and the charge limit threshold of SOC is c MAX . The storage battery charge amount correction is configured to perform the normal operation until the correction start SOC, and correct the output in a linear function so that the output becomes 0 at the SOC upper limit from the correction start SOC to the SOC upper limit. doing. P _SPk ^lmt represents the discharge rated output of storage battery B _k , and when the discharge rate is C _rate ^P and the rated capacity of storage battery B _k is WH _S ^lmt , it is ^calculated by C _rate ^P × WH _S ^lmt . Therefore, in the equation (5c), the calculated individual target power P _Bk ^ref is within the range between the charge rated output and the discharge rated output defined based on the set C rate (charge rate and discharge rate). It is limited to fit within. That is, the value obtained by dividing the output current (individual output power P _Bk ^out ) of each power conditioner PCS _Bk by the rated capacity of storage battery B _k does not exceed the set C rate due to the restriction by equation (5c). Is controlled by Therefore, the C rate can be said to be a characteristic value for limiting the output current (individual output power P _Bk ^out ) in each power conditioner PCS _Bk .

In the above equation (5d), α _k and β _k represent adjustment parameters that can be adjusted by the remaining amount of the storage battery B _k . For example, when the charging rate SOC _k of the storage battery B _k is 90% or more, the alpha _k 0, the beta _k By setting the P _Bk ^lmt, be limited to perform only discharged by the (5d) equation. Further, when the charging rate SOC _k of the storage battery B _k is less 10%, the alpha _k -P _Bk ^lmt, the beta _k by setting a 0, it can be limited to perform only charging the above (5d) equation. Furthermore, when the charging rate SOC _k of the storage battery B _k is between them (greater than 10% less than 90%), the alpha _k -P _Bk ^lmt, the beta _k By setting the P _Bk ^lmt, also charging discharging Can also be restricted to do.

In the above equation (5e), Q _Bk is the reactive power of each power conditioner PCS _Bk , S _Bk ^d is the maximum apparent power that can be output from each power conditioner PCS _Bk , and V ₀ is a reference of interconnection point at design time The voltage, V _Bk , represents the voltage at the interconnection point in each power conditioner PCS _Bk .

In the present embodiment, as the weight w _Bk (see the above equation (5a)) regarding the active power of each power conditioner PCS _Bk , a value calculated by the following equation (8) is used. In the following equation (8), pr _B ^lmt indicates the control index limit of the control index pr _B. The control index limit pr _B ^lmt, the control indicator when charging and discharging the storage battery B _k with maximum possible output power, i.e., when the individual output power P _Bk ^out is charged and discharged at 100% of the rated output P _Bk ^lmt Control index. Further, w _SOCk indicates a weight according to the SOC of the storage battery B _k , and P _Bk ^max is a power that can be output to the maximum when various constraints in the storage battery B _k are taken into account (hereinafter referred to as “constraint maximum output "Is indicated. The constraint maximum output P _Bk ^max is set based on the battery B _k charger rated output P _SMk ^lmt, rated output P _Bk ^lmt discharge rated output P _SPk ^lmt and power conditioner PCS _Bk of the battery B _k . Specifically, compared with the positive and negative values a value obtained by inverting the sign of the discharge rated output P _SPk ^lmt charging rated output P _SMk ^lmt, seek whichever is larger. Then, this larger value is compared with the value of the rated output P _Bk ^lmt , and the smaller value is set as the constraint maximum output P B _k ^max . In the plurality of power conditioners PCS _Bk , weights w _Bk may be used for all the same active power.
w _Bk = pr _B ^lmt / (2 × w _SOCk × P _Bk ^max ) (8)

FIG. 4 shows the relationship between the control index pr _B and the individual output power P _Bk ^out when the weight w _Bk relating to the active power of each power conditioner PCS _Bk is used as described above. FIG. 4 shows each of three power conditioners PCS _{Bk having} different rated outputs P _Bk ^lmt . In the present embodiment, each power conditioner PCS _Bk charges storage battery B _k when individual output power P _Bk ^out is a negative value, and discharges storage battery B _k when individual output power P _Bk ^out is a positive value. Do. Further, since the individual output power _PBk ^out is controlled to become the individual target power _PBk ^ref calculated by the target power calculation unit 33, the figure shows the control index pr _B and the individual target power _PBk ^ref It can be said that the relationship between In FIG. 4, the control index limit pr _B ^lmt is ^set to 100. Further, in FIG. 4, which shows what the rated output P _Bk ^lmt is 500kW solid, those rated output P _Bk ^lmt is 250kW dashed rated output P _Bk ^lmt is those 100kW by a dashed line.

As shown in FIG. 4, each time the control index pr _B rises by 20 between -100 (the control index limit pr _B ^lmt is a negative value) to 100 (the control index limit pr _B ^lmt ), the rated output If P _Bk ^lmt is 500kW 100 kW, if the rated output P _Bk ^lmt is 250 kW 50 kW, the rated output P _Bk ^lmt is reduced by 20kW for 100 kW. This would have reduced by 20% of the rated output P _Bk ^lmt of the power conditioner PCS _Bk. That is, it controls the individual output power P _Bk ^out a percentage of the rated output P _Bk ^lmt of the power conditioner PCS _Bk. Therefore, even if the change amount of the control index pr _{B is} the same, the charge / discharge amount of the storage battery B _k changes according to the rated output P _Bk ^lmt of the power conditioner PCS _Bk . Further, each power conditioner PCS _Bk individually has the same value as the rated output P _Bk ^lmt when the control index pr _B is a value (−pr _B ^lmt ) with the control index limit pr _B ^{lmt set} to a negative value. The storage battery B _k is discharged at the output power P _Bk ^out . On the other hand, when control index pr _B is at control index limit pr _B ^lmt , storage battery B _k is charged with individual output power P _Bk ^out having the same value as rated output P _Bk ^lmt . In other words, the storage battery B _k is charged and discharged with power that can be output to the maximum extent. Furthermore, when the control index pr _B is 0, the individual output power P _Bk ^out is 0. Then, as shown in FIG. 4, the individual output power _PBk ^out linearly changes. From the above, in setting the weight w _Bk relating to the active power, by using the above equation (8), the ratio of the power conditioner PCS _{Bk to} the rated output P _Bk ^lmt with each change of the control index pr _B Storage battery B _k can be charged and discharged. Therefore, a plurality of power conditioners PCS _Bk, be different their rated output P _Bk ^lmt, when the absolute value of the control index pr _B is control index limit pr _B ^lmt, 100% of the rated output P _Bk ^lmt Storage battery B _k can be charged and discharged. Specifically, when control index pr _B is a negative value of control index limit pr _B ^lmt , storage battery B _k is discharged at 100% of rated output P _Bk ^lmt , and control index pr _B is control index limit pr When it is the value of _B ^lmt , storage battery B _k can be charged with 100% of rated output P _Bk ^lmt . When the same value is used as the weight w _Bk related to the active power, the individual output power P _Bk ^out is uniformly reduced by the same amount even if the rated output P _Bk ^lmt of each power conditioner PCS _Bk is different. It can be configured.

The output control unit 34 is configured the same as the output control unit 23. The output control unit 34 controls the discharge and charge of the storage battery B _{k to set} the individual output power P _Bk ^out to the individual target power P _Bk ^ref calculated by the target power calculation unit 33. Specifically, when the individual target power P _Bk ^ref calculated by the target power calculation unit 33 is a positive value, the power (DC power) stored in the storage battery B _k is converted into AC power, and the power line 90 is used. Output. That is, the power conditioner PCS _Bk functions as a discharge circuit. On the other hand, when the individual target power P _Bk ^ref is a negative value, AC power input via the power line 90 is converted to DC power and supplied to the storage battery B _k . That is, the power conditioner PCS _Bk functions as a charging circuit.

Next, in the solar power generation system PVS1 according to the first embodiment, an operation when changing the setting value of the C rate of each power conditioner PCS _Bk will be described.

For example, in order to change the setting value of the C rate of each power conditioner PCS _Bk , the user designates an operation of specifying a new setting value (request value) different from the current setting value as the operating device of the central management device MC1. If done using (not shown), the C rate designation unit 15 creates a C rate designation value based on the request value designated by this operation, and transmits this to each power conditioner PCS _Bk . For example, it is assumed that the current C rate setting value in each power conditioner PCS _Bk is 0 C, and 1 C is specified as a new setting value (request value). At this time, the C rate designation unit 15 transmits the request value 1C as the C rate designation value to each of the power conditioners PCS _Bk .

Next, in each power conditioner PCS _Bk , the C rate setting unit 32 receives the C rate designation value transmitted from the C rate designation unit 15 of the central management device MC1. Then, when the C rate setting value (the above reception setting value) at the time of receiving the C rate specification value is different from the C rate specification value received, the C rate setting unit 32 sets the C rate setting value as Change in steps from the reception setting value to the C rate specification value. Specifically, the C rate setting unit 32 changes the setting value of the C rate from the reception setting value to the C rate designation value by a unit update amount that is preset in each predetermined update cycle. For example, if the reception setting value is 0 C and the received C rate specification value is 1 C, the reception rate setting value and the C rate specification value are different, so the C rate setting unit 32 sets the C rate setting value. From 0C which is a setting value at reception time to 1C which is a C rate specification value, it is increased by 0.05C (unit update amount) each time 1 sec elapses after receiving the C rate specification value (every update cycle). Therefore, in this case, the C rate setting unit 32 changes the set value of the C rate in each of the power conditioners PCS _Bk in a stepwise manner over 20 seconds.

As described above, when the user performs an operation to change the C rate setting value in the centralized management device MC1, the C rate setting value is changed from the reception setting value to the C rate in each power conditioner PCS _Bk . Gradually change to the specified value.

Next, in the solar power generation system PVS1, changes in the output power of the solar power generation system PVS1 when changing the set value of the C rate were verified by simulation. Moreover, simulation was similarly performed also in conventional solar power generation system PVS0. In addition, conventional solar power generation system PVS0 uses power conditioner PCS _Bk 'instead of power conditioner PCS _Bk which concerns on solar power generation system PVS1 of this embodiment. The power conditioner PCS _Bk 'are those having a conventional C-rate setting unit in place of the C-rate setting unit 32 of the power conditioner PCS _Bk, other configurations are the same as power conditioner PCS _Bk. The conventional C rate setting unit is not to change the setting value of the C rate in a stepwise manner as in the C rate setting unit 32 but to change it at one time (change it according to the C rate specified value) It is.

In this simulation, the set value of the discharge rate C _rate ^P was changed from 0 C to 1 C. Moreover, in this simulation, the control index pr _B was fixed at −100, assuming the power conditioners PCS _Bk ′ and PCS _Bk whose control index limit pr _B ^lmt is 100 (see FIG. 4).

FIG. 5 (a) shows a simulation result in the conventional solar power generation system PVS0, and FIG. 5 (b) shows a simulation result in the solar power generation system PVS1 of this embodiment. 5 (a) and 5 (b), the upper time chart (upper diagram) shows the time change of the control index pr _B with respect to the power conditioners PCS _Bk 'and PCS _Bk , and the middle time chart (middle diagram) shows the power conditioning na PCS _Bk ', C rate (discharge rate C _rate ^P) in the PCS _Bk of a temporal change in the set value, the lower time chart (lower chart) is the power conditioner PCS _Bk', the individual output power at PCS _Bk P _Bk ^out Shows the time change of. The broken lines shown in the middle part of FIGS. 5 (a) and 5 (b) indicate the time change of the C rate designation value transmitted from the central management device MC1. Further, FIG. 5 (a), (b) lower view of the solar power generation system PVS0, PVS1 comprises a plurality of power conditioners PCS _Bk ', one of the power conditioner PCS _Bk of the PCS _Bk', It is a simulation result in power conditioner PCS _Bk 'which is PCS _Bk and whose rated output is 250 kW, and PCS _Bk .

In the solar power generation system PVS0, as shown in FIG. 5A, a period from the start of simulation until the C rate designated value of the discharge rate C _rate ^P is changed (time t = 0 to 10 [sec] In the above, 0 C is set to the set value of the discharge rate C _rate ^P. Therefore, the individual target power P _Bk ^ref calculated by the target power calculation unit 33 is 0 kW according to the C rate constraint shown in the above-mentioned equation (5c). Since the output control unit 34 controls the individual output power _PBk ^{out to} be the individual target power _PBk ^{ref in the} power conditioner PCS _Bk ′, as shown in the lower diagram of FIG. _Bk ^out is 0 kW. Then, when the C rate designation value of the discharge rate C _rate ^P is changed at time t = 10 [sec], the set value of the discharge rate C _rate ^P is 0 C to 1 C as shown in the middle diagram of FIG. Has been changed to. As a result, as shown in FIG. 5 (a) lower chart, it has become instantaneously 250kW individual output power P _Bk ^out the time t = 10 [sec]. When PV system PVS0 has one power conditioner PCS _Bk ', it is only a change of 250kW, for example, when it has 100 power conditioner PCS _Bk ' whose rated output is 250kW The power of 25 MW will change instantaneously. This may adversely affect the power system A, as described above. In addition, power control of the solar power generation system PVS0 may not be properly performed.

On the other hand, in the solar power generation system PVS1, as shown in FIG. 5B, in the period of time t = 0 to 10 [sec], it is the same as the conventional solar power generation system PVS0. However, when the C rate designation value of the discharge rate C _rate ^P is changed at time t = 10 [sec], the setting value of the discharge rate C _rate ^P is 1 sec, as shown in the middle part of FIG. 5B. Every time it passes, it increases by 0.05C. This is because the C rate setting unit 32 increases the set value of the discharge rate C _rate ^P by 0.05 C each time one second elapses. In this case, the set value of the discharge rate C _rate ^P is as increased by 0.05 C, as shown in the lower diagram of FIG. 5 (b), the individual output power P _Bk ^out has increased by approximately 12.5 kW. This is because, in the C rate constraint (the above equation (5c)) of the optimization problem (the above equation (5)), the upper limit value of the C rate constraint is 12.5 kW (= 0.05 [C] × 250 [kW]) It is because it increases one by one. Therefore, the calculated individual target power P _Bk ^ref increases by 12.5 kW, and the individual output power P _Bk ^out increases by 12.5 kW. Then, when 20 seconds have passed after the C rate designation value of the discharge rate C _rate ^P is changed (time t = 30 [sec]), the set value of the discharge rate C _rate ^P becomes 1 C, and the individual output power P _Bk ^out is 250 kW which is a rated output of the power conditioner PCS _Bk .

In the above simulation, the case of increasing the set value of the discharge rate C _rate ^P, the discharge rate C _rate ^P setting the same when reduced, discharge rate C _rate ^P set value stepwise Thus, the output power (individual output power P _Bk ^out ) gradually decreases.

From the above, even if the solar power generation system PVS1 performs an operation to change the set value of the C rate (discharge rate C _rate ^P ), the interconnection point power P (t) is rapidly Can be suppressed. That is, it is possible to suppress the rapid change of the output power of the solar power generation system PVS1. Although the above simulation shows the case where the set value of discharge rate C _rate ^P is changed, each power conditioner can be changed stepwise even when the set value of charge rate C _rate ^M is changed. The output power from PCS _Bk to storage battery B _k can be changed stepwise. That is, also when charging the storage battery B _k , the solar power generation system PVS1 can suppress the rapid change of the output power of the solar power generation system PVS1.

  Next, the operation and effect of the solar power generation system PVS1 according to the first embodiment will be described.

According to the first embodiment, the C rate setting unit 32 determines the C rate setting value based on the C rate specification value received from the C rate specification unit 15 when the C rate specification value is received. Change stepwise from the set value (set value at reception) to the C rate specified value. As a result, the calculated individual target power P _Bk ^ref changes stepwise in the same manner as the change in the C rate setting value, so the individual output power P _Bk ^out also changes in the same manner as the C rate setting value changes. It changes gradually. From the above, even if the C-rate specified value is changed, the set value of the C-rate is not changed at one time, and therefore, it is possible to suppress a rapid change in the output power of the solar power generation system PVS1. Therefore, it is possible to suppress the adverse effect on power system A caused by the abrupt change in the output power of solar power generation system PVS1. In addition, by suppressing the rapid change of the output power of the solar power generation system PVS1, it is possible to suppress that the power control using the control indexes pr _PV and pr _B can not be appropriately performed.

In the first embodiment, the case where the user performs the operation of specifying the request value using the operation device (not shown) of the central management device MC1 is shown, but the present invention is not limited to this. For example, it may be a management device for managing a plurality of solar power generation systems PVS1 collectively, and may be configured to be able to specify a request value in a central management device above the central management device MC1. In this case, when the user performs an operation of specifying a request value in the central management device, the request value specified by this operation is transmitted to the central management device MC1. Then, the central management device MC1 transmits the received request value as a C rate designation value to each power conditioner PCS _Bk .

In the first embodiment, the C rate designation value is transmitted from the central management device MC1, and each of the power conditioners PCS _Bk that receives this transmits the C rate setting value stepwise from the reception value setting value to the C rate specification value. However, the present invention is not limited to this. For example, the following modification is possible. That is, when the user performs an operation to change the request value to the central management device MC1, the C rate specification unit 15 of the central management device MC1 changes the request value before the change operation to the request value after the change operation. While changing the designated value in stages, each change is transmitted to each power conditioner PCS _Bk . And each power conditioner PCS _Bk makes the setting value of C rate the received C rate designated value. Even with this configuration, since the set value of the C rate of each power conditioner PCS _Bk is changed stepwise, it is possible to suppress a rapid change in the output power of the solar power generation system PVS1. When the user can specify a request value in the central management unit as described above, the specified request value is transmitted from the central management unit to the central management unit MC1, and the central management unit MC1 is the central management unit. , And may be configured to transmit a C rate designation value that changes in stages to each of the power conditioners PCS _Bk based on the request value received from.

  In the first embodiment, the case where the set value of the C rate is changed by the user operation is shown, but the change of the set value of the C rate is not limited to this. Also in the situation described below, since the set value of the C rate may be changed, the set value of the C rate may be changed stepwise even in such a situation.

For example, at the time of peak cut control, the discharge of the storage battery B _k is prioritized, and the power stored in the storage battery B _k decreases. Therefore, there is a possibility that a situation may occur where the necessary power is not stored in the storage battery B _k despite the desire to discharge the storage battery B _k by peak cut control. Therefore, by changing the set value of the charging rate C _rate ^M, controls the charging of the battery B _k, is to keep charging the battery B _k comprises the discharge by the next peak cut control. For example, when the set value of the charge rate C _rate ^M is 0 C, charging can be prevented, and the charge rate can be increased as the set value of the charge rate C _rate ^M is increased. Even when the set value of the charge rate C _rate ^M is changed in such control, the output of the solar power generation system PVS1 can be changed by changing the set value of the C rate (charge rate C _rate ^M ) in stages. Abrupt changes in power can be suppressed.

In addition, for example, in reverse power flow avoidance control, charging of storage battery B _k is prioritized, and power is accumulated in storage battery B _k . Therefore, the reverse power flow avoidance control despite wants to charge the battery B _k, battery B _k is fully charged, there is a possibility that the situation where the charging of the battery B _k can not be performed occurs. Therefore, by changing the set value of the discharge rate C _rate ^P, to control the discharge of the battery B _k, which may keep discharging the storage battery B _k comprises the charging by the next reverse power flow avoidance control. For example, when the set value of the discharge rate C _rate ^P is 0 C, the discharge can be prevented, and the discharge rate can be increased as the set value of the discharge rate C _rate ^P is increased. Even when the set value of the discharge rate C _rate ^P is changed in such control, the output of the solar power generation system PVS1 can be changed by changing the set value of the C rate (discharge rate C _rate ^P ) stepwise. Abrupt changes in power can be suppressed.

In addition, when the setting value of C rate is changed, it is not limited to two above-mentioned examples, Also in other cases, photovoltaic power generation system PVS1 sets the setting value of C rate of each power conditioner PCS _Bk You can change it in stages.

  Next, a solar power generation system PVS2 according to a second embodiment will be described. In addition, about the structure the same as that of 1st Embodiment, or similar, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The whole structure of solar power generation system PVS2 is the same as that of solar power generation system PVS1 which concerns on 1st Embodiment shown in FIG.

FIG. 6 shows a mechanical configuration of a control system related to power control of the solar power generation system PVS2. As shown to the same figure, compared with the said solar power generation system PVS1, solar power generation system PVS2 differs in the point in which each power conditioner PCS _Bk is further provided with the connection judgment part 35. FIG.

Connection determination unit 35 determines whether or not own device (power conditioner PCS _Bk ) is connected to power line 90. In the following description, the state connected to the power line 90 is referred to as "connected state", and the state not connected to the power line 90 is referred to as "non-connected state". Each power conditioner PCS _Bk can perform charging and discharging of storage battery B _{k in} the connected state, and can not perform charging and discharging of storage battery B _{k in} the non-connected state. The connection state or the non-connection state is determined based on, for example, the state of a switch (not shown) for connecting each power conditioner PCS _Bk to the power line 90. Connection determination unit 35 determines that power conditioner PCS _Bk is in a connection state when the switch is in a conduction state, and when the switch is in a disconnection state, power conditioner PCS _Bk is in a non-connection state. I will judge.

Even if the C rate setting unit 32 in the second embodiment receives the C rate designation value transmitted from the central management device MC1 (C rate designation unit 15), the connection determination unit 35 determines that the C rate setting unit 32 is in the non-connection state. If the C rate is not set, the C rate setting value is not set to the received C rate designated value, but is set to a predetermined value. In the present embodiment, 0C is used as the predetermined value, but it is not limited to this. On the other hand, when it is determined by the connection determination unit 35 that the connection state is established, the set value of the C rate is set to the received C rate designated value. Therefore, when the C rate designation value received from the C rate designation unit 15 is different from the predetermined value, it is necessary to change the setting value of the C rate when switched from the non-connection state to the connection state. For example, when each power conditioner PCS _Bk is newly connected to the power line 90, each power conditioner PCS _Bk switches from the disconnected state to the connected state. Therefore, the C rate setting unit 32 changes the setting value of the C rate stepwise from the predetermined value to the C rate designated value when switching from the disconnection state to the connection state. The method of changing the setting value of the C rate in a stepwise manner by the C rate setting unit 32 is the same as that of the C rate setting unit 32 according to the first embodiment.

Next, in the solar power generation system PVS2, when the power conditioner PCS _Bk having a rated output of 250 kW changes from the non-connection state to the connection state, the output power of the power conditioner PCS _Bk (individual output power P _Bk ^out ) The change of was verified by simulation. In addition, similarly to the first embodiment, the simulation was similarly performed also in the conventional solar power generation system PVS0.

In this simulation, it is assumed that 1 C is transmitted as a C rate designated value of the discharge rate C _rate ^P from the central management device MC 1 to the power conditioners, PCS _Bk ′, and PCS _Bk . Further, as in the simulation in the first embodiment, the control index pr _B is fixed at -100.

Fig.7 (a) is a simulation result in conventional solar power generation system PVS0, FIG.7 (b) has each shown the simulation result in solar power generation system PVS2 of this embodiment. 7A and 7B, the upper time chart (upper diagram) shows the time change of the control index pr _B with respect to the power conditioners PCS _Bk 'and PCS _Bk , and the middle time chart (middle diagram) shows the power condition na PCS _Bk ', C rate (discharge rate C _rate ^P) in the PCS _Bk of a temporal change in the set value, the lower time chart (lower chart) is the power conditioner PCS _Bk', the individual output power at PCS _Bk P _Bk ^out Shows the time change of. 7 (a) and 7 (b) are the same as FIG. 5, the power of any one of the plurality of power conditioners PCS _Bk 'and PCS _Bk included in the solar power generation systems PVS0 and PVS1. It is a simulation result in power conditioner PCS _Bk 'and PCS _Bk which are conditioner PCS _Bk ' and PCS _Bk and whose rated output is 250 kW. In this simulation, it is assumed that the power conditioners PCS _Bk ′ and PCS _Bk are switched from the non-connection state to the connection state at time t = 5 [sec]. That is, at time t = 0 to 5 [sec], power conditioners PCS _Bk 'and PCS _Bk are not connected, and at time t = 5 to 35 [sec], power conditioner PCS _Bk ', PCS It is assumed that _Bk is in a connected state.

In the photovoltaic system PVS0, even if the power conditioner PCS _Bk ′ is not connected, if the C rate designated value is received from the centralized management device MC1, the C rate set value is the C rate. It was configured to be the specified value. Therefore, as shown in the middle diagram of FIG. 7A, the power conditioner PCS _Bk ′ is in a disconnected state (time t = 0 to 5 [sec]) and in a connected state (time t = t). In both of 5 to 35 [sec]), 1 C is set as the set value of the discharge rate C _rate ^P. Further, in the solar power generation system PVS0, as shown in the lower part of FIG. 7A, the power conditioner PCS _Bk ′ is not electrically connected in a disconnected state (time t = 0 to 5 [sec]) The individual output power _PBk ^out is 0 kW even if 1 C is set to the set value of the discharge rate C _rate ^P. On the other hand, since the power can be output in the connected state (time t = 5 to 35 [sec]), the individual output power _PBk ^out is 250 kW according to the set value (1C) of the discharge rate C _rate ^P . Therefore, at the same time as the power conditioner PCS _Bk ′ changes from the unconnected state to the connected state, the individual output power _PBk ^out instantaneously rises to 250 kW of the rated output. In the photovoltaic system PVS0, when one power conditioner PCS _Bk 'is changed from the non-connected state to the connected state, the change is 250 kW, but a large number of power conditioners PCS _Bk ' are simultaneously disconnected When the connection state is established, the output power of the solar power generation system PVS0 changes rapidly. This may adversely affect the power system A. In addition, power control of the solar power generation system PVS0 may not be properly performed.

On the other hand, in the solar power generation system PVS2, as shown in the middle diagram of FIG. 7 (b), the power conditioner is in a disconnected state (time t = 0 to 5 [sec]) when the power conditioner PCS _Bk is not connected. Even if the PCS _Bk receives the C rate designation value from the central management device MC1, the setting value of the discharge rate C _rate ^P is a predetermined value (0 C). Then, when power conditioner PCS _Bk changes from the disconnection state to the disconnection state at time t = 5 [sec], the setting value of discharge rate C _rate ^P changes from the predetermined value (0 C) to the C rate designation value (1 C) once. In each of 1 sec from the predetermined value (0 C), the temperature rises by 0.05 C. Then, at time t = 25 [sec], the set value of the discharge rate C _rate ^P becomes the C rate specified value (1 C). Therefore, as shown in the middle diagram of FIG. 7B, the setting value of the discharge rate C _rate ^P is a predetermined value (0 C) when the power conditioner PCS _Bk is in the non-connected state, and the connection is started from the non-connected state. In the state, it is understood that the C rate designated value (1C) received from the central management device MC1 is gradually changed (raised). In addition, as shown in the lower diagram of FIG. 7B, the individual output power P _Bk ^out is not associated with the above-mentioned solar light in a period (time t = 0 to 5 [sec]) in which the power conditioner PCS _Bk is not connected. As in the case of the power generation system PVS0, although it is 0 kW, it can be seen that after the connection state is reached, it gradually rises in accordance with the change in the set value of the discharge rate C _rate ^P. Also in this simulation, since the set value of the discharge rate C _rate ^P changes by 0.05 C every 1 sec, the individual output power _PBk ^out rises by 12.5 kW every 1 sec. doing. Then, a time t = 25 in [sec], the individual output power P _Bk ^out is the rated output of the power conditioner PCS _Bk 250 kW. From the above, the solar power generation system PVS2 can suppress the rapid change of the output power of the solar power generation system PVS2 even when the power conditioner PCS _Bk changes from the non-connection state to the connection state. There is.

Furthermore, it verified by simulation that the case where solar power generation system PVS2 is self-consumption type. In this simulation, it is assumed that the solar power generation system PVS2 has a reverse power relay installed and reverse power flow avoidance control is performed. Further, in this simulation, it is assumed that the solar power generation systems PVS2 and PVS0 consume 200 kW of power by the power load L, and have one power conditioner PCS _Bk with a rated output of 250 kW. I assumed. Further, in this simulation, the predetermined value when the power conditioner PCS _Bk is in the non-connected state is 0 C, and the C rate designated value is 1 C. In this simulation, unlike the other simulations described above, the control index pr _B is changed by the interconnection point power P (t) and the target power P ^C (reverse power flow avoidance target value).

FIG. 8 (a) shows a simulation result in the photovoltaic system PVS0, and FIG. 8 (b) shows a simulation result in the photovoltaic system PVS2. 8A and 8B, the upper time chart (upper diagram) shows the time change of the control index pr _B with respect to the power conditioners PCS _Bk 'and PCS _Bk , and the middle time chart (middle diagram) shows the sunlight The time change of the interconnection point power P (t) in the power generation systems PVS0 and PVS2 is shown, and the lower time chart (lower diagram) shows the time change of the individual output power _PBk ^{out in} the power conditioners PCS _Bk 'and PCS _Bk . ing. In the middle diagrams of FIGS. 8A and 8B, the alternate long and short dash line indicates the operation level of the reverse power relay, and the alternate long and short dash line indicates the reverse power flow avoidance target value. Also in this simulation, it is assumed that the power conditioners PCS _Bk ′ and PCS _Bk are switched from the non-connection state to the connection state at time t = 5 [sec], as in the simulation shown in FIG.

In the solar power generation system PVS0, when the power conditioner PCS _Bk 'changes from the non-connection state to the connection state at time t = 5 [sec], as shown in the lower diagram of FIG. _Bk ^out instantaneously rises to 250 kW. As a result, as shown in the middle diagram of FIG. 8A, the interconnection point power P (t) becomes a positive value, which exceeds the operation level (0 kW) of the reverse power relay. Therefore, a reverse power flow state occurs, and the reverse power relay operates. Thereby, the photovoltaic power generation system PVS0 is disconnected from the power system A by the reverse power relay.

On the other hand, in the solar power generation system PVS2, when the power conditioner PCS _Bk changes from the non-connection state to the connection state at time t = 5 [sec], the set value of the discharge rate C _rate ^P is changed stepwise As shown in the lower part of FIG. 8B, the individual output power _PBk ^out rises stepwise. Therefore, as shown in the middle diagram of FIG. 8 (b), the interconnection point power P (t) also rises in stages. Then, when the interconnection point power P (t) exceeds the backward flow avoidance target value, the backward flow avoidance control is performed such that the interconnection point power P (t) matches the backward flow avoidance target value. Thus, as shown in the upper diagram of FIG. 8B, at time t = 15 [sec], the control index pr _B starts to rise from −100 (the absolute value of the control index pr _B decreases, ie, Start changing towards 0). As a result, at time t = 20 [sec], as shown in the lower diagram of FIG. 8B, the individual output power _PBk ^out is suppressed, and the increase turns to a decrease. Therefore, as shown in the middle diagram of FIG. 8 (b), the interconnection point power P (t) is also turned from the decrease to the increase, and the interconnection point power P (t) is controlled to become the reverse power flow avoidance target value. ing. At time t = 15 to 20 [sec], since the control index pr _B is rising (because the absolute value of the control index pr _B is decreasing), the individual output power P _Bk ^out is suppressed. Although it should be controlled in so that, the individual output power P _Bk ^out has increased as it is not inhibited (see lower chart in Figure 8 (b)). This is because the set value of the discharge rate C _rate ^P is higher (C rate constraint (the above equation (5c)) than the individual target power P _Bk ^ref (see the above equation (5a)) calculated by the control index pr _B This is because the individual target power P _Bk ^ref determined in accordance with the increase in the upper limit value is smaller, and the individual target power P _Bk ^ref finally calculated by the target power calculation unit 33 corresponds to the discharge rate C _rate ^P As it is determined, the individual output power P _Bk ^out is not suppressed but is rising. In the time t = 20 [sec] after the individual target power P _Bk ^ref Gayori calculated by the control indicator pr _B also, the discharge rate C _rate ^P setting individual target power P _Bk determined in response to an increase in ^{since ref} increases, with increasing control index pr _B (a decrease in the absolute value of the control index pr _B), the individual target power P _Bk ^ref is finally calculated by the target electric power calculating unit 33 is reduced, the individual Output power P _Bk ^out is suppressed.

From the simulation results described above, the photovoltaic power generation system PVS2 can suppress rapid increase in the interconnection point power P (t). Further, the solar power generation system PVS2 can suppress the interconnection point power P (t) exceeding the operation level (0 kW) of the reverse power relay by changing the setting value of the C rate and changing the control index pr _B. . That is, the solar power generation system PVS2 can appropriately perform the power control using the control indexes pr _PV and pr _B, and can suppress the operation of the reverse power relay.

In the two simulations according to the present embodiment described above, the case where the set value of the discharge rate C _rate ^P is increased is shown, but also in the case where the set value of the discharge rate C _rate ^P is decreased Since the set value of the discharge rate C _rate ^P gradually decreases when the power supply PCS _Bk changes from the unconnected state to the connected state, the output power (individual output power P _Bk ^out ) gradually decreases. Moreover, in these simulations, although the case where the set value of the discharge rate C _rate ^P is changed is shown, the setting of the charge rate C _rate ^M is similarly performed when the set value of the charge rate C _rate ^M is changed. By changing the value stepwise, it is possible to change the output power from each power conditioner PCS _Bk to the storage battery B _k stepwise. That is, also when charging the storage battery B _k , the solar power generation system PVS2 can suppress a rapid change of the output power of the solar power generation system PVS2 similarly.

  Next, the operation and effect of the photovoltaic power generation system PVS2 according to the second embodiment will be described.

According to the second embodiment, the C rate setting unit 32 sets the C rate set value to a predetermined value when each power conditioner PCS _Bk is not connected, and when each power conditioner PCS _Bk is connected. The setting value of C rate was made to be C rate specified value. Then, the C rate setting unit 32 designates the C rate setting value from the predetermined value to the C rate specification when each power conditioner PCS _Bk changes from the disconnection state to the connection state and the C rate setting value needs to be changed. It changed gradually to the value. Thereby, when each power conditioner PCS _Bk changes from a non-connection state to a connection state, it can suppress that the individual output electric power _PBk ^{out of} each power conditioner PCS _Bk changes rapidly. Therefore, since the output power of the photovoltaic system PVS2 can be prevented from changing rapidly, it is possible to suppress the adverse effect and control indicators pr _PV to the power grid, the power control using the pr _B not properly performed. In particular, as can be seen from the simulation results shown in FIG. 8, when the solar power generation system PVS2 is a self-consumption type, the setting value of the C rate of each power conditioner PCS _Bk is changed in stages to make the solar power generation system By suppressing a rapid change in the output power of the PVS 2, the possibility of the photovoltaic system PVS 2 being disconnected from the power system A can be reduced.

According to the second embodiment, 0 C is used as the predetermined value in the non-connected state. Thus, each power conditioner PCS _Bk may limit the individual target power P _Bk ^ref calculated to zero by the C rate constraint (the above equation (5c)) of the optimization problem represented by the above equation (5). it can. That is, each individual output power _PBk ^out of each power conditioner PCS _Bk can be limited to zero. Therefore, when each power conditioner PCS _Bk changes from the disconnection state to the connection state, it is possible to change each individual output power PB _k ^out from 0 kW.

In the second embodiment, although the C conditioner designated value is received from the central management device MC1 even in the non-connected power conditioner PCS _Bk , the present invention is not limited to this. For example, the power conditioner PCS _Bk does not receive the C rate designation value transmitted from the central management device MC1 in the non-connection state, and the C rate transmitted from the central management device MC1 in the connection state. It may be configured to receive a designated value.

In the second embodiment, each power conditioner PCS _Bk determines whether it is in the non-connected state or in the connected state, and in the non-connected state, the setting value of the C rate is set to a predetermined value, It is not limited to this. For example, as long as the central management device MC1 can determine whether each power conditioner PCS _Bk is in the connected state or not connected, it may be configured as follows. That is, the central management device MC1 transmits the above predetermined value as a C rate designated value to the power conditioner PCS _Bk which is not connected, and the C rate designated to the power conditioner PCS _Bk which is connected. Send request value as value. Then, when the power conditioner PCS _Bk in the non-connection state is in the connection state, the C rate designation unit 15 of the central management device MC1 changes the C rate designation value stepwise while changing it from the predetermined value to the request value. Every time, the C rate designation value at that time is transmitted to the power conditioner PCS _Bk that has changed from the unconnected state to the connected state. The power conditioner PCS _Bk sets the C rate setting value to the received C rate designated value. Even in the case of such a configuration, since the setting value of the C rate of each power conditioner PCS _Bk is changed stepwise, it is possible to suppress the rapid change of the output power of the solar power generation system PVS2. .

In the second embodiment, the case where the power conditioner PCS _Bk is _switched from the unconnected state to the connected state is described, but it is also conceivable that all or part of the power conditioner PCS _PVi is changed from the unconnected state to the connected state. . That is, it may be considered that power conditioner PCS _PVi is newly connected to power line 90. At this time, immediately after the power conditioner PCS _PVi is in the connected state, the interconnection point power P (t) may change rapidly depending on the solar radiation condition and the like. However, as described above, the power conditioner PCS _PVi performs maximum power point tracking control (MPPT control), and the individual output power P _PVi ^out of the power conditioner PCS _PVi is set to a predetermined cycle (the present implementation by this MPPT control). In the form, it changes stepwise in 1 sec). The power conditioner PCS _PVi is performed control using control index pr _PV, individual target power P _PVi ^ref in calculation period of the control index pr _PV (1 sec in this embodiment) is calculated. By these controls, each individual output power P _PVi ^out can be controlled so as not to change rapidly.

Next, a solar power generation system PVS3 according to a third embodiment will be described. In the first and second embodiments, the case where the interconnection point power P (t) detected by the interconnection point power detection unit 12 is used as the adjustment target power. In this embodiment, the sum of the individual output powers P _PVi ^out and P _Bk ^{out of the} power conditioners PCS _PVi and PCS _Bk and the power consumption P _L of the power load L is calculated and used as the adjustment target power. Show. In the following description, the sum of the individual output powers P _PVi ^out and P _Bk ^{out of the} power conditioners PCS _PVi and PCS _Bk and the power consumption P _L of the power load L is referred to as “system total output”. Thus, solar systems PVS3 controls to the total system output the target power P ^C.

FIG. 9 shows the overall configuration of the solar power generation system PVS3. As shown in the figure, the solar power generation system PVS3 includes a plurality of solar cells SP _i , a plurality of power conditioners PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioners PCS _Bk , and a central management device MC3. It is configured to have.

The solar power generation system PVS3 according to the present embodiment does not detect the interconnection point power P (t), and the individual output powers P _PVi ^out and P _Bk ^{out of the} power conditioners PCS _PVi and PCS _Bk and the power load L total power consumption P _L is calculated (system total output P _total (t)). System total output P _total (t) is determined by the arithmetic expression ^{_{"Σ i P PVi out + Σ k}} P Bk out -P L ". Then, the calculated _total system output P _total (t) is controlled to match the target power P ^C as the output (adjustment target power) of the entire photovoltaic power generation system PVS 3. That is, the solar power generation system PVS3 performs various types of power control using the _total system output P _total (t) instead of the interconnection point power P (t).

FIG. 10 shows a functional configuration of a control system related to power control of the solar power generation system PVS3 shown in FIG. In FIG. 10, illustration of the solar cell SP _i and the storage battery B _k is omitted. Also, only the first power conditioners PCS _PVi and PCS _Bk are described. The solar power generation system PVS3 differs in that a centralized management device MC3 is provided instead of the centralized management device MC1 according to the first embodiment. Also, the configurations of the power conditioners PCS _PVi and PCS _Bk are different.

In the third embodiment, as shown in FIG. 10, each power conditioner PCS _PVi further includes an output power detection unit 24 and a transmission unit 25 as a control system in power control. Further, as shown in FIG. 10, each of the power conditioners PCS _Bk further includes an output power detection unit 36 and a transmission unit 37 as a control system in power control.

The output power detection unit 24 is included in each of the power conditioners PCS _PVi , and detects the individual output power P _PVi ^out of the own device. The output power detection unit 36 is provided in each of the power conditioners PCS _Bk , and detects an individual output power _PBk ^out of the own device.

The transmitter 25 transmits the individual output power P _PVi ^out detected by the output power detector 24 to the central management device MC3. The transmission unit 37 transmits the individual output power _PBk ^out detected by the output power detection unit 36 to the central management device MC3.

  As shown in FIG. 10, the central management device MC3 specifies the target power setting unit 11, the receiving unit 16, the total output calculating unit 17, the index calculating unit 18, the transmitting unit 14, and the C rate as a control system in power control. Part 15 is included. That is, as compared with the centralized management device MC1 according to the first embodiment, the receiving unit 16, the total output calculating unit 17, and the index calculating unit 18 instead of the interconnection point power detecting unit 12 and the index calculating unit 13. It differs in the point which it has.

The receiving unit 16 receives individual output powers P _PVi ^out and P _Bk ^out transmitted from the power conditioners PCS _PVi and PCS _Bk . The receiving unit 16 receives the power consumption P _L that is transmitted from the power load L.

Total output calculating section 17, receiving section 16 has received, and calculates the individual output power P _PVi ^out, P _Bk ^out and power load L power P _L is the sum of the total system output P _total of (t). In the present embodiment, the total output calculation section 17, calculates all the individual output power P _PVi ^out, P _Bk ^out and power load L consumption P _L addition the systems total output P _total of the (t) input Do.

The index calculation unit 18 calculates an index (control index pr _PV , pr _B ) for setting the _total system output P _total (t) calculated by the total output calculation unit 17 to the target power P ^C. At this time, the index calculation unit 18 calculates the Lagrange multiplier λ using the _total system output P _total (t) instead of the interconnection point power P (t) in the above equation (1). Then, the calculated Lagrange multiplier λ is calculated as the control indexes pr _PV and pr _{B according to} the above equation (2). The calculated control index pr _PV is transmitted to each of the power conditioners PCS _PVi via the transmission unit 14. Further, the calculated control index pr _B is transmitted to each of the power conditioners PCS _Bk via the transmission unit 14.

Also in the solar power generation system PVS3 configured as described above, the setting value of the C rate of each power conditioner PCS _Bk can be changed stepwise in the same manner as in the first embodiment. . Thereby, as in the first embodiment, even when the C rate designated value is changed, it is possible to suppress a rapid change in the output power of the solar power generation system PVS3.

The solar power generation system PVS3 according to the third embodiment is a system total output P _total (t) instead of the interconnection point power P (t) as the adjustment target power in the solar power generation system PVS 1 according to the first embodiment. In the solar power generation system PVS2 according to the second embodiment, the system total output P _total (t) is used instead of the interconnection point power P (t) as the adjustment target power. It may be configured. In this case, as in the second embodiment, even when the power conditioners PCS _Bk are switched from the non-connection state to the connection state, it is possible to suppress a rapid change in the output power of the solar power generation system PVS3.

Further, in the schedule control in the third embodiment, the output power of the entire photovoltaic power generation system PVS 3 (system total output P _total (t)) is not used as the adjustment target power, but a plurality of power conditioners PCS _PVi and PCS are used. _{When Bk} is divided into a plurality of groups, the output power of each group may be used. In this case, target power is set for each group, and schedule control is performed so that the output power of each group becomes the target power of the group.

In the first to third embodiments, the C rate setting value in each power conditioner PCS _Bk is changed by a preset unit update amount (for example, 0.05 C). However, the present invention is limited thereto. I will not. For example, every time the C rate specification value is changed, the C rate setting unit 32 may appropriately change the unit update amount based on the difference between the reception setting value and the C rate specification value. Specifically, in each power conditioner PCS _Bk , the time required to change from the reception set value to the C rate designated value (hereinafter referred to as “required time”) and the update period are set in advance. Then, when the C rate designation value is changed, the difference between the reception set value and the C rate designation value (target update amount) is calculated, and the calculated target update amount, the required time, and the update period are used. , “Target update amount ÷ (necessary time ÷ update period)” is calculated. This calculation result is used as a unit update amount. For example, it is assumed that the required time is set to 20 sec, the update cycle is set to 1 sec, and the C rate designation value is changed from 0C to 0.5C. That is, it is assumed that the reception setting value of 0 C is changed to the C rate designation value of 0.5 C in a necessary time of 20 sec in an update cycle of 1 sec. At this time, the C-rate setting unit 32 first calculates the difference between the reception setting value and the C-rate designation value (0.5C-0C) to calculate the target update amount as 0.5C. Next, the C rate setting unit 32 uses the calculated target update amount to calculate a unit update amount of 0.025 C (= 0.5 [C] ÷ (20 [sec] ÷ 1 [sec]) according to the above equation. Calculate with)). Therefore, the unit update amount in this case is 0.025C. Moreover, when changing from 0 C which is a setting value at reception to 2 C which is a C-rate specified value over the necessary time of 20 sec in an update cycle of 1 sec, the C rate setting unit 32 similarly calculates unit update amount Is 0.1 C (= 2 [C] ÷ (20 [sec] ÷ 1 [sec])). As described above, the unit update amount may be changed each time the C rate specification value is changed. The above-mentioned numerical value is an example and it is not limited to this.

When changing the unit update amount as described above, an upper limit value of the unit update amount is provided, and when the calculated unit update amount exceeds the set upper limit value, it is limited by the upper limit value. It is good to be configured. By doing this, it is possible to suppress a rapid change in the individual output power _PBk ^{out of} each power conditioner PCS _Bk due to the unit update amount becoming too large. Further, either the first unit update amount or the second unit update amount different from each other may be used according to the calculated target update amount. Specifically, when the calculated target update amount is less than the predetermined threshold, the C rate setting unit 32 uses the first unit update amount set in advance and the calculated target update amount is equal to or greater than the threshold. The second unit update amount set in advance may be used. The second unit update amount is larger than the first unit update amount. Moreover, even if any of the first unit update amount and the second unit update amount is used, the unit update amount obtained by the above-mentioned arithmetic expression (“target update amount / (necessary time / update period)”) is used. Good.

In the first to third embodiments, the case where the “characteristic value” of the present invention is a C rate has been described as an example, but the present invention is not limited to this. For example, a constraint different from the constraint in the optimization problem shown in the above equation (5) is used, and a characteristic value which limits input / output power at the time of charge and discharge of storage battery B _k is used as the constraint. In this case, the setting value of the characteristic value may be changed stepwise in place of the setting value of the C rate.

In the first to third embodiments, the case where the central management device MC1 (MC3) calculates the control indexes pr _PV and pr _B is shown, but the present invention is not limited to this. For example, the central management device MC1 (MC3) may calculate individual target power P _PVi ^ref and P _Bk ^ref for each of the plurality of power conditioners PCS _PVi and PCS _Bk instead of the control indexes pr _PV and pr _B. It is also good. In this case, the central management device MC1 (MC3) generates a plurality of power conditioners PCS _PVi , based on the power to be adjusted (interconnection point power P (t) or total system output P _total (t)) and target power. The individual target power P _PVi ^ref and P _Bk ^ref for each PCS _Bk are calculated. Then, each of the power conditioners PCS _PVi and PCS _Bk obtains the individual target power P _PVi ^ref and P _Bk ^ref for the own device from the centralized management device MC1 (MC3), and the individual output power P _PVi ^out and P _Bk ^out are individually Control is performed to achieve target power P _PVi ^ref and P _Bk ^ref . At this time, each power conditioner PCS _Bk has limited input / output power at the time of charge / discharge of storage battery B _k , that is, individual output power P _Bk ^out , based on the set value of C rate to be set. Even in such a case, rapid change of the output power of the photovoltaic power generation system can be suppressed by the C rate setting unit 32 changing the setting value of the C rate in a stepwise manner.

  In the first to third embodiments, although the case where the power system of the present disclosure is a solar power generation system has been described as an example, the present invention is not limited thereto. The power system may be another power generation system. Other power generation systems include, for example, a wind power generation system, a power generation system using a fuel cell, a power generation system using a rotary generator, a virtual power generation system for managing the load of customers by an aggregator that performs negawatt trading, etc. Conceivable. The aggregator, however, does not actually generate electricity because it treats the saved electricity as generated electricity through the Negawatt Trading. Also in these power generation systems, the central control device detects the interconnection point power or calculates the sum of the individual output powers to be the adjustment target power, calculates the index, and transmits it to each power control device. Then, the power control device of each power generation system calculates the individual target power of the own device based on the optimization problem using the received index, and controls the individual output power so as to be the individual target power. In the case of a solar power generation system, a wind power generation system or a power generation system using a fuel cell, the power control device is a power conditioner. Further, in the case of a power generation system using a rotary generator, the power controller is a generator and a controller that controls the generator. Moreover, in the case of the power generation system by an aggregator, a power control apparatus is a load of a consumer and a control apparatus which controls this. In addition, in the power generation system by the aggregator, since the saved power is regarded as the generated power, the power reduced from the normal power consumption of the load of the customer becomes the individual output power. In addition, the power system may use the above-described power generation system in combination. For example, a configuration in which a rotating machine type generator is added to a photovoltaic power generation system, and a centralized management device sends an index to each power conditioner and generator control device of the photovoltaic power generation system to control the overall output It may be

  The power system and the storage battery power conditioner according to the present disclosure are not limited to the above embodiment, and the specific configuration of each part can be variously changed in design without departing from the contents described in the claims. It is.

PVS1 to PVS3: photovoltaic system A: power system L: power loads MC1, MC3: centralized management device 11: target power setting unit 12: interconnection point power detection unit 13: index calculation unit 14: transmission unit 15: C rate designating section 16: reception section 17: total output calculation section 18: index calculating unit SP _i: solar PCS _PVi: power conditioner 21: receiver 22: target power calculation unit 23: output control section 24: output power detection unit 25 : transmission unit B _k: battery PCS _Bk: power conditioner 31: receiving unit 32: C-rate setting unit 33: target power calculation unit 34: output control section 35: connection determination unit 36: output power detection unit 37: transmission unit 90 : Power line

Claims (8)

A power control unit to which power is input from the power generation unit;
A storage battery power conditioner that controls charging and discharging of the storage battery,
A power line to which the power control device and the storage battery power conditioner are connected and which is connected to a power system;
A central control unit for managing the power control unit and the storage battery power conditioner;
The storage battery power conditioner includes setting means for setting a characteristic value for limiting input / output power when charging and discharging the storage battery,
The characteristic value set by the setting means is stepwise changed from the currently set current value to the specified value when a change to a specified value which is a new set value is performed.
Power system characterized by. The centralized management device includes a designation unit that transmits the designated value to the storage battery power conditioner.
The setting means gradually changes the characteristic value from the current value to the designated value received from the centralized management device.
The power system according to claim 1. The storage battery power conditioner further includes connection determination means for determining whether or not the storage battery is connected to the power line,
The setting means sets a predetermined value to the characteristic value when it is determined that the connection is not connected by the connection determination means, and sets the characteristic value as the specified value when it is determined that the property value is connected. change,
The power system according to claim 1 or claim 2. The characteristic value is a C rate indicating a relative ratio of input / output current at charging / discharging to the total capacity of the storage battery.
The power system according to any one of claims 1 to 3. The centralized management device calculates an index for controlling the power to be adjusted to the target power,
Each of the power control unit and the storage battery power conditioner controls an individual output power based on an optimization problem using the index.
The power system according to any one of claims 1 to 4. The characteristic value is used as a constraint in the optimization problem of the storage battery power conditioner.
The power system according to claim 5. A storage battery power conditioner connected to a power line connected to a power system and controlling input / output power when charging and discharging the storage battery,
Target power calculation means for calculating an individual target power which is a target value of the output power of the storage battery power conditioner;
An output control unit configured to control an individual output power to be the individual target power;
Setting means for setting a characteristic value for limiting input / output power when charging / discharging the storage battery;
Equipped with
When changing the characteristic value to a specified value which is a new set value, the setting means changes the current value currently set from the current value to the specified value in stages.
Storage battery power conditioner characterized by. It further comprises receiving means for receiving an indicator for controlling input / output power at the time of charging / discharging of the storage battery, which is transmitted from a centralized management device that manages the storage battery power conditioner,
The target power calculation means calculates the individual target power based on an optimization problem using the index.
The storage battery power conditioner according to claim 7.

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