JP6318734B2 - Distributed power system controller, power conditioner, distributed power system, and distributed power system control method - Google Patents

Description

  The present invention relates to a distributed power supply system control device, a power conditioner, a distributed power supply system, and a control method for a distributed power supply system, in which a storage battery is provided in the power generation device to suppress fluctuations in output power.

  In recent years, a natural energy power generation apparatus that generates power using natural energy, which is clean energy, has been spreading while attention has been paid to global environmental problems. In this natural energy generator, the output may fluctuate greatly due to changes in the weather. As one of measures for suppressing this output fluctuation, a system combining a natural energy power generation device and a storage battery has been proposed. In this system, while maintaining the charge level appropriately with a storage battery, it is studied to suppress a steep output fluctuation as a whole system and absorb a gradual output fluctuation with the frequency adjustment power of the system. In addition, a storage battery may be added to the cogeneration system or the fuel cell, and the same control may be performed. Note that, as described above, a system in which a power generation device such as a natural energy power generation device, a cogeneration system, or a fuel cell and a storage battery are combined is referred to as a distributed power system below.

  However, in this distributed power system, the amount of power generated by a power generator such as a natural energy power generator, a cogeneration system, or a fuel cell rises and falls sharply. There is a case where an increase in charge / discharge current rate per time and an increase in the number of times of charge / discharge are caused. As a result, there is a risk that the utilization efficiency of the generated power is reduced and the life of the storage battery is shortened.

  On the other hand, the technique which suppresses the charging / discharging current rate per unit time and the frequency | count of charging / discharging of a storage battery using a change rate limiting filter is proposed (for example, refer nonpatent literature 1). However, in this technology, the change rate limiting filter is effective for all the generated power, and as a result, the fluctuation suppression rate of the supplied power due to the combination of the power generation device and the storage battery may decrease. It was. In addition, since the change speed of the generated power in all directions is limited in the above technology, the change speed from the charge direction to the charge direction and the change speed from the discharge direction to the discharge direction, which do not need to be limited so much, are also included. It was limited and could not be said to be an efficient change rate limit.

Japanese Patent No. 4609156

Yuichi Miyazaki and three others, "Development of output fluctuation suppression control method for photovoltaic power generation using storage battery-Proposal of output fluctuation suppression control method using change speed limit-", Central Research Laboratory Research Report, Research Report R10034, May 2011

The present invention has been invented in view of the above-described prior art. The purpose of the present invention is in a distributed power supply system that combines a storage battery with a power generator such as a natural energy power generator, a cogeneration system, or a fuel cell. By reducing the number of charge / discharge switchings,
It is to provide a technology for realizing a long life of a storage battery or realizing more efficient power supply.

  The present invention for solving the above problems comprises a power generation means and a storage battery, and when the amount of power generated by the power generation means is insufficient with respect to the amount of power load, the battery is discharged from the storage battery according to the shortage, The absolute value of the deviation between the power generation amount of the power generation means and the power load amount with respect to the control device for the distributed power supply system that charges the storage battery according to the surplus amount when the power generation amount by the power generation means is greater than the power load amount Is smaller than the case where the absolute value of the deviation is larger, the deviation value between the power generation amount and the power load amount of the power generation means is converted so that the fluctuation is more largely suppressed. Thus, the greatest feature is to reduce the frequency of switching between the state of discharging from the storage battery and the state of charging the storage battery.

More specifically, power generation means for outputting power,
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A control device for a distributed power supply system comprising:
When the amount of power generated by the power generation means is insufficient with respect to the amount of power load, the power generation amount by the power generation means is supplemented with the amount of power generated by the power generation means by discharging from the storage battery according to the shortage. Control means for charging the storage battery with electric power corresponding to the surplus amount when the load amount is larger than the load amount;
Fluctuation suppression means for converting the deviation value between the power generation amount of the power generation means and the power load amount so that the fluctuation is suppressed;
A distributed power supply system comprising:
When the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is smaller than the case where the absolute value of the deviation is larger, the power generation amount of the power generation means by the fluctuation suppression means Charge / discharge switching suppression that reduces the frequency at which the state of discharging from the storage battery and the state of charging of the storage battery are switched by the control means by increasing the degree of suppression of variation in deviation from the power load amount Means
It is characterized by providing.

  That is, in the present invention, when the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is smaller, the variation suppression means performs the above-described case when the absolute value of the deviation is larger. The degree of suppression of variation in deviation between the power generation amount of the power generation means and the power load amount is increased. Then, when the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is closer to 0, the variation in the deviation between the power generation amount of the power generation means and the power load amount becomes smaller. As a result, the frequency at which the state of discharging from the storage battery and the state of charging the storage battery are switched by the control means is reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the burden to a storage battery can be reduced by reducing the frequency with which the state discharged from the storage battery and the state charged to the storage battery are switched. As a result, it is possible to extend the life of the storage battery. In addition, according to the present invention, since the variation in deviation between the power generation amount of the power generation means and the power load amount is not suppressed in all cases, the fluctuation suppression rate of the supplied power by the combination of the power generation means and the storage battery is reduced. Therefore, efficient power supply can be performed.

Further, in the present invention, the charge / discharge switching suppression means has one or a plurality of threshold values for the deviation between the power generation amount of the power generation means and the power load amount, and the power generation amount and power load amount of the power generation means Based on the relationship between the absolute value of the deviation and the threshold, the deviation is divided into a plurality of regions according to the magnitude of the absolute value of the deviation, and in the region where the absolute value of the deviation is smaller, Compared with the region where the absolute value of the deviation is larger, the fluctuation suppression means is connected to the power generation means of the power generation means so that the change rate of the deviation between the power generation amount of the power generation means and the power load amount becomes a smaller value. The deviation between the amount and the power load amount may be converted.

  That is, in the present invention, based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and one or more prepared threshold values, the deviation is set to the magnitude of the absolute value of the deviation. It is divided into a plurality of corresponding areas. Thus, the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is classified into at least two levels according to the value.

  In the present invention, in the region where the absolute value of the deviation is smaller, the change rate of the deviation between the power generation amount of the power generation means and the power load amount is higher than in the region where the absolute value of the deviation is larger. The deviation between the power generation amount of the power generation means and the power load amount is converted by the fluctuation suppression means so as to be a small value. That is, when the deviation value is small, the deviation value is converted so that the variation rate of the deviation becomes smaller.

  As a result, the frequency at which the state of discharging from the storage battery and the state of charging the storage battery are switched by the control means is reduced, and as a result, the burden on the storage battery can be reduced and the life of the storage battery can be reduced. It becomes possible to make it longer. In addition, in all cases, the fluctuation suppression rate of the supplied power due to the combination of the power generation means and the storage battery is reduced as compared with the case where the fluctuation of the deviation between the power generation amount of the power generation means and the power load amount is suppressed. It can be suppressed, and more efficient power supply can be performed.

  Further, in the present invention, the charge / discharge switching suppression means is configured to calculate the deviation based on a relationship between an absolute value of a deviation between the power generation amount of the power generation means and the power load amount and a predetermined threshold value. When the value is divided into a first region having a smaller value and a second region having a larger absolute value of the deviation, and the deviation belongs to the first region, You may make it convert so that the deviation with an electric power load amount may be converted so that the rate of change may be suppressed.

  That is, in the present invention, based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and a predetermined threshold value, the deviation is determined according to the magnitude of the absolute value of the deviation. And divide into the second area. In the present invention, in the first region where the absolute value of the deviation is smaller, the fluctuation suppressing means is configured so that the change rate of the deviation between the power generation amount of the power generation means and the power load amount becomes a smaller value. The deviation between the power generation amount of the power generation means and the power load amount is converted.

  As a result, the frequency at which the state of discharging from the storage battery and the state of charging the storage battery are switched by the control means is reduced, and as a result, the burden on the storage battery can be reduced and the life of the storage battery can be reduced. It is possible to make it longer. In addition, in all cases, the fluctuation suppression rate of the supplied power due to the combination of the power generation means and the storage battery is reduced as compared with the case where the fluctuation of the deviation between the power generation amount of the power generation means and the power load amount is suppressed. It can be suppressed, and more efficient power supply can be performed.

Further, in the present invention, the charge / discharge switching suppressing means has a state in which a variation in a deviation between a power generation amount of the power generation means and a power load amount is discharged from the storage battery and a state in which the storage battery is charged. Charge / discharge switching determining means for determining whether or not the change is switched;
The charge / discharge switching determination means determines that the variation in the deviation between the power generation amount and the power load amount of the power generation means is a change in which the state of discharging from the storage battery and the state of charging the storage battery are switched. In this case, the fluctuation suppression unit may convert the deviation between the power generation amount of the power generation unit and the power load so that the rate of change is suppressed.

  That is, in the present invention, the change in the deviation between the power generation amount of the power generation means and the power load amount is a change in which the state of discharging from the storage battery and the state of charging the storage battery are switched by the charge / discharge switching determination means. When it is actually determined, the fluctuation suppression means converts the deviation between the power generation amount of the power generation means and the power load amount so that the rate of change is suppressed.

  According to this, when the fluctuation of the deviation between the amount of power generated by the power generation means and the amount of power load is actually a change in which the state of discharging from the storage battery and the state of charging of the storage battery are switched, the control means This reduces the frequency at which the state of discharging from the storage battery and the state of charging the storage battery are switched. As a result, the burden on the storage battery can be reduced more reliably, and the life of the storage battery can be extended more reliably. Further, in all cases, more efficient power supply can be performed as compared with the case where the variation in deviation between the power generation amount of the power generation means and the power load amount is suppressed.

  Moreover, in this invention, the said electric power generation means is good also as a solar power generation means to generate electric power by converting sunlight energy into electric power with a solar cell. According to this, in a photovoltaic power generation system that combines a solar battery and a storage battery, which are now widely used as renewable energy, the burden on the storage battery can be reduced, and the life of the storage battery can be made longer. Is possible.

The present invention also includes the above control device,
A power conversion device that performs voltage conversion and / or DC / AC conversion of each output between at least one of the power generation means and the storage battery and at least one of a power load and a system;
It may be a power conditioner of a distributed power supply system characterized by comprising:

Alternatively, the present invention provides the above control device,
Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A distributed power supply system characterized by comprising:

Further, the present invention provides the above power conditioner,
Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A distributed power supply system characterized by comprising:

Further, the present invention provides power generation means for outputting electric power,
A storage battery that stores electric power and is charged or discharged according to a deviation between an electric power generation amount and an electric power load amount of the electric power generation means,
With the amount of power generation to supplement power generation amount by the power generating means and discharged from said storage battery in response to said non foot amount if missing to power load amount by the power generating means, the power generation amount by the power generating means power When there is more than the load amount, the storage battery is charged with electric power according to the surplus amount, and the control method of the distributed power system,
When the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is smaller, the deviation between the power generation amount of the power generation means and the power load amount than when the absolute value of the deviation is larger. The frequency of switching the value so that the fluctuation is suppressed more greatly, thereby reducing the frequency of switching between the state of discharging from the storage battery and the state of charging the storage battery, It may be a control method of the power supply system.

  Further, in this case, based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and one or a plurality of threshold values, the deviation is set to the magnitude of the absolute value of the deviation. In a region where the absolute value of the deviation is smaller, the deviation between the power generation amount of the power generation means and the power load amount is compared with a region where the absolute value of the deviation is larger. A control method for a distributed power supply system may be characterized in that the deviation between the power generation amount of the power generation means and the power load amount is converted so that the change rate of the power supply becomes a smaller value.

  Further, in this case, based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and a predetermined threshold value, the deviation is defined as the first region where the absolute value of the deviation is smaller. , When the deviation is divided into a second region having a larger absolute value and the deviation belongs to the first region, the variation rate of the deviation between the power generation amount of the power generation means and the power load amount is suppressed. It may be a control method of a distributed power supply system, characterized in that conversion is performed as described above.

  Further, in this case, it is determined that the variation in the deviation between the power generation amount of the power generation means and the power load amount is a variation in which the state in which the storage battery is discharged and the state in which the storage battery is charged are switched. In this case, the control method of the distributed power supply system may be characterized in that the deviation between the power generation amount of the power generation means and the power load amount is converted so that the rate of change is suppressed.

  Also, the present invention may be a control method for a distributed power system, wherein the power generation means is a solar power generation means for generating power by converting solar energy into electric power by a solar cell. .

  Note that means for solving the above-described problems can be used in combination as much as possible.

  According to the present invention, in a distributed power system that combines a storage battery with a power generation device such as a natural energy power generation device, a cogeneration system, or a fuel cell, the life of the storage battery is extended by reducing the number of times of switching between charging and discharging of the storage battery. Or more efficient power supply can be realized.

It is a figure which shows schematic structure of the solar energy power generation system in Example 1 of this invention. It is a figure which shows the system configuration | structure of the control apparatus in Example 1 of this invention. It is a block diagram which shows the content of the conventional charge / discharge amount control. It is a block diagram which shows the content of charge / discharge amount control at the time of inserting the conventional rate limiter. It is a graph which shows the relationship between the deviation | deviation of the electric power generation amount and load amount of a solar cell at the time of utilizing the conventional rate limiter, and the deviation output after passing a rate limiter. It is a flowchart of the rate limiter control logic for suppression of the deviation fluctuation | variation by the dynamic rate limiter in Example 1 of this invention. It is a block diagram which shows the content of the charge / discharge amount control in Example 1 of this invention. It is a graph which shows the relationship between the deviation | deviation of the electric power generation amount and load amount of a solar cell in Example 1 of this invention, and the deviation output after passing a dynamic rate limiter. It is the graph which took the limit value of the change rate at the time of making the conventional rate limiter work on the horizontal axis, and took FRR and the number of times of charging / discharging on the vertical axis. It is the graph which took the regulation value of the absolute value of the deviation of the electric power generation amount and load amount of a solar cell on the horizontal axis, and the number of times of charge and discharge of FRR and the solar cell on the vertical axis regarding the dynamic rate limiter in Example 1 of the present invention. . It is the graph which took the prescription | regulation value of the absolute value of the deviation of the electric power generation amount and load amount of the solar cell in Example 1 of this invention on the horizontal axis, and took the charging rate and the discharge rate on the vertical axis | shaft. It is the graph which took the limit value of the fluctuation | variation speed in the case of making a rate limiter work in the dynamic rate limiter in Example 1 of this invention on a horizontal axis, and took FRR and the frequency of charging / discharging on the vertical axis | shaft. It is a figure which shows the result of having performed the simulation about the case where there is no limiter, the rate limiter use, and the dynamic rate limiter use about the charge / discharge frequency in 36 patterns including a season, weather, and load. It is a figure which shows the result of having simulated FRR in 36 patterns including a season, weather, and load about the case where there is no limiter, the rate limiter is used, and the dynamic rate limiter is used. In the case of vermicelli, with no limiter, using the rate limiter, and using the dynamic rate limiter according to this example, the measurement results of the power generation amount and load amount of the solar cell, the charge / discharge of the storage battery, and the receiving end trading power is there. Measurement of solar cell power generation and load deviation, storage battery charging / discharging, and receiving end trading power for each case of no sunny limiter, late limiter use, and dynamic rate limiter use according to this example in case of sunny summer It is a result. Measurement of solar cell power generation and load deviation, storage battery charging / discharging, and receiving end trading power for each case of summer without rain limiter, rate limiter use, and dynamic rate limiter use according to this example. It is a result. In the case of autumn rain, with no limiter, using the rate limiter, and using the dynamic rate limiter according to this embodiment, the measurement results of the deviation of the power generation amount and load amount of the solar cell, the charge / discharge of the storage battery, and the receiving end trading power is there. In the case of cloudy winter season, no limiter, use of rate limiter, use of dynamic rate limiter according to this example, measurement of solar power generation amount and load amount, storage battery charge / discharge, receiving end trading power measurement It is a result. It is a flowchart of the rate limiter control logic 2 for the suppression of the deviation fluctuation | variation by the multilevel dynamic rate limiter in Example 2 of this invention. It is a block diagram which concerns on the control content of the multilevel dynamic rate limiter in Example 2 of this invention. It is a figure which shows the relationship between the deviation of the electric power generation amount and load amount of a solar cell in Example 2 of this invention, and the deviation output after performing control control of the deviation fluctuation | variation by a multilevel dynamic rate limiter. In Example 2, it is the graph which took the limit value 2 in the deviation range of the 2nd step on the horizontal axis, and took FRR and the number of times of charging / discharging on the vertical axis. In Example 2, when the limit value 2 is set to 0.4, the horizontal axis represents the specified value 2 and the vertical axis represents FRR and the number of charge / discharge cycles. It is the result of having performed the simulation about the case where a dynamic rate limiter is used and the case where the multi-level dynamic rate limiter concerning this example is used about the number of times of charge and discharge in a pattern including season, weather, and load in example 2. . It is the result of having performed simulation about the case where a dynamic rate limiter is used, and the case where the multi-level dynamic rate limiter which concerns on a present Example is used about FRR in the pattern containing a season, the weather, and load in Example 2. FIG. 10 is a flowchart of a rate limiter control logic 3 for suppressing deviation variation by the directional dynamic rate limiter in the third embodiment. In Example 3, it is a figure which shows the relationship between the deviation of the electric power generation amount and load amount of a solar cell, and the deviation output at the time of using a directional dynamic rate limiter. FIG. 10 is a diagram for describing rules for controlling a limited directional dynamic rate limiter in the fourth embodiment. It is a figure which shows another example of the relationship between the deviation of the electric power generation amount and load amount of a solar cell in Example 3, and a deviation output at the time of using a directional dynamic rate limiter. In Example 4, it is a figure which shows the relationship of the deviation output at the time of using the deviation of the electric power generation amount and load amount of a solar cell, and a limited directional dynamic rate limiter. It is a figure which shows the variation of schematic structure of the solar energy power generation system in the Example of this invention.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. In the following embodiments, a solar cell will be described as an example of power generation means, but the application target of the present invention is not limited to solar power generation.

  <Example 1>

  FIG. 1 shows a schematic configuration of a photovoltaic power generation system 1 that is an example of a distributed power supply system in the present embodiment. The solar power generation system 1 is provided with a solar cell 2 that generates power using solar energy as natural energy. The output of the solar cell 2 is input to a DC / DC conversion circuit 3 that converts the DC output of the solar cell 2 into a voltage and boosts the voltage. The direct current power output from the DC / DC conversion circuit 3 is converted into alternating current by the bidirectional DC / AC conversion circuit 4. The output of the bidirectional DC / AC conversion circuit 3 is connected to the system 8 and the load 9.

  When the grid 8 is operating normally, the photovoltaic power generation system 1 is in a linked operation state linked to the grid 8. At that time, the bidirectional DC / AC conversion circuit 4 outputs AC power to the system 8 and the load 9. When the output power from the bidirectional DC / AC conversion circuit 4 is smaller than the power consumption of the load 9, the shortage may be automatically supplied from the system 8 to the load 9. Conversely, when the output power from the bidirectional DC / AC conversion circuit 4 is greater than the power consumption of the load 9, the surplus may be automatically supplied to the system 8.

  Moreover, the solar power generation system 1 in the present embodiment includes a storage battery 5. In the present embodiment, the description is made on the assumption that a lithium ion battery is used as the storage battery 5, but the storage battery 5 may be another type such as a NaS battery (sodium-sulfur battery). . The output of the storage battery 5 is connected to a bidirectional DC / DC conversion circuit 6 for voltage conversion. The output of the bidirectional DC / DC conversion circuit 6 is connected to the output of the DC / DC conversion circuit 3. Thereby, when there is more power consumption of the load 9 than the electric power generated by the solar cell 2, the power consumption of the load 9 is satisfied by complementing the electric power discharged from the storage battery 5. In addition, as described above, the amount of power generated by the solar battery 2 greatly fluctuates due to the influence of the weather, and there is a possibility that the power quality such as voltage fluctuation and frequency fluctuation of the grid 8 may be adversely affected. With this power supply, fluctuations in generated power in the combination of the solar battery 2 and the storage battery 5 are suppressed.

  Further, when the power consumption of the load 9 is less than the power generated by the solar battery 2 and the amount of charge of the storage battery 5 is insufficient, the part of the power generated by the solar battery 2 that is not supplied to the load 9 is the storage battery 5. Is supplied to the storage battery 5 through the bidirectional DC / DC conversion circuit 6. In addition, when the amount of charge of the storage battery 5 is insufficient and the amount of power generated by the solar battery 2 that is not supplied to the load 9 is insufficient as the power for charging the storage battery 5, Power may be supplied from 8 to the storage battery 5 through the bidirectional DC / AC conversion circuit 4 and the bidirectional DC / DC conversion circuit 6.

  The control of the charge / discharge amount from the storage battery 5 is realized by controlling the bidirectional DC / DC conversion circuit 6 by a microprocessor (not shown) included in the control device 7 and a program executed on the microprocessor. The microprocessor and program (not shown) correspond to control means in this embodiment. The control device 7 measures the output power of the DC / DC conversion circuit 3 with a PV power generation amount sensor, which will be described later, and measures the load power at the load 9 with a load amount sensor, and according to the amount of deviation, Control the amount of charge and discharge. Note that the range indicated by the broken line in FIG. 1, that is, the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, the control device 7, and the bidirectional DC / DC conversion circuit 6 are housed in the form of a power conditioner 1a. It may be placed in the body. Alternatively, only the control device 7 is an independent device, and a range indicated by a dotted line, that is, the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, and the bidirectional DC / DC conversion circuit 6 are in the form of a power conditioner 1b. You may arrange | position in one housing | casing. Here, at least one of the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, and the bidirectional DC / DC conversion circuit 6 corresponds to the power conversion device in the present embodiment.

  In FIG. 2, the system block diagram of the control apparatus 7 is shown. The control device 7 includes, in addition to the CPU 76, the ROM 77, and the RAM 78, the voltage sensor 71 and the current sensor 72 as the PV power generation amount sensor described above, and the voltage sensor 73 and the current sensor 74 as the load amount sensor. The analog output from these sensors is digitized by an AD converter 74. A control signal of the control device 7 is input to the bidirectional DC / DC conversion circuit 6 for charge / discharge amount control through the I / O interface 75.

  In FIG. 3, the block diagram of the conventional charge / discharge amount control by the control apparatus 7 is shown. As shown in FIG. 3, in the conventional charge / discharge amount control, the deviation between the power generation amount by the solar cell 2 and the load amount of the load 9 and the charge / discharge amount by the storage battery 5 approaches the target value. Thus, charge / discharge control based on the control logic is performed. When this target value is 0, control is basically performed so that there is no power transfer to and from the grid 8.

As described above, the power supply from the storage battery 5 suppresses fluctuations in the generated power in the combination of the solar battery 2 and the storage battery 5. The fluctuation suppression effect is evaluated by the following fluctuation reduction rate (FRR).

FRR = (Spv−Sgd) / Spv × 100 (1)

Here, Spv is the magnitude of the frequency spectrum component in a predetermined frequency range obtained by performing FFT (Fast Fourier Transform) on the solar cell output. Sgd is the magnitude of the frequency spectrum component in a predetermined frequency range obtained by performing FFT on the output at the linkage point after the combination of the outputs of the solar cell 2 and the storage battery 5. Therefore, it means that the larger the FRR value, the greater the effect of suppressing fluctuations in generated power in the combination of the solar cell 2 and the storage battery 5. (Nobuya Naoi and two others, “Verification test of photovoltaic power generation system with output fluctuation suppression function”, Toshiba Review, Vol.67 No.1 (2012), p.14-17)

  In this way, fluctuations in the amount of power generated by the solar cell 2 due to changes in the weather are absorbed and suppressed by the storage battery 5, so depending on the weather and the load amount of the load 9, the storage battery 5 per unit time Since the charging / discharging current rate increases or the number of times of charging / discharging of the storage battery 5 increases, the power generation efficiency due to the combination of the solar battery 2 and the storage battery 5 decreases, and the life of the storage battery 5 is shortened. There was a case.

On the other hand, conventionally, a countermeasure using a “change rate limiting filter” has been proposed.
As shown in FIG. 4, a rate limiter 760 as an example of a variation suppressing unit is inserted with respect to the amount of deviation between the power generation amount and the load amount of the solar cell 2, and the power generation amount and the load amount of the solar cell 2. The absolute value of the rate of change of deviation is always limited to a specified value or less.

Here, the change rate (rate) of the deviation between the power generation amount and the load amount of the solar cell 2 is expressed by the following equation.

Rate = (y (x) −y (x−1)) / (t (x) −t (x−1)) (2)

Here, t (x) is the x-th sampling time, and y (x) is a physical quantity at t (x) (in this case, the deviation between the power generation amount and the load amount of the solar cell 2).

  In the rate limiter 760, assuming that the maximum rise rate is Rp and the maximum fall rate is Rn, y (x) is output as it is when the rate is equal to or less than the limit value Rp and equal to or greater than Rn. Rp is output when the rate is equal to or greater than the limit value Rp, and Rn is output when the rate is equal to or less than Rn. When this rate limiter 760 is used, the relationship between the power generation amount and load amount deviation of the solar cell 2 and the deviation output after passing through the rate limiter 760 is as shown in FIG. In FIG. 5, the target value in FIG.

  In FIG. 5, the horizontal axis represents time, and the vertical axis represents power, but the power values themselves are for convenience. This is the same for the similar graphs in the following description. A dotted line indicates a deviation between the power generation amount and the load amount of the solar cell 2, and a solid line indicates a deviation output when the rate limiter 760 is operated. As can be seen from FIG. 5, by inserting the rate limiter 760, variation in the deviation between the power generation amount and the load amount of the solar cell 2 (hereinafter also referred to as deviation variation) is suppressed. As a result, the fluctuation of the charge / discharge amount by the storage battery 5 is also suppressed, and the number of times of switching between charge / discharge is also reduced. However, in the measure for inserting the rate limiter 760, the rate of change is limited regardless of the value of the deviation between the power generation amount and the load amount of the solar cell 2. For this reason, when the deviation between the power generation amount and the load amount of the solar cell 2 greatly increases, the change cannot be sufficiently compensated for by the storage battery 5, and fluctuations in the generated power due to the combination of the solar cell 2 and the storage battery 5. In some cases, a sufficient suppression effect could not be obtained.

  Further, in the measure for inserting the rate limiter 760, from the viewpoint of suppressing the shortening of the life of the storage battery 5, it is not necessary to suppress the deviation variation so much that the storage battery 5 is discharged from the charge direction or the discharge direction. Deviation fluctuations in the direction are also limited. Therefore, it cannot be said that the fluctuation suppression of the generated power by the combination of the solar cell 2 and the storage battery 5 is efficiently performed.

  On the other hand, in this embodiment, a dynamic rate limiter 760 is employed that operates the rate limiter 760 only when the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than a specified value. FIG. 6 shows a flowchart of the rate limiter control logic for suppressing deviation fluctuation by the dynamic rate limiter. The rate limiter control logic is a program stored in the ROM 77 of the control device 7 and is executed by the CPU 76.

When this logic is executed, first, in S101, it is determined whether or not the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than a specified value. Here, when it is determined that the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is larger than the specified value, the deviation variation is caused such as from the charging direction to the discharging direction or from the discharging direction to the charging direction. Since it is determined that the charge / discharge direction of the storage battery 5 is not likely to be switched, the process proceeds to S104. On the other hand, when it is determined in S101 that the absolute value of the deviation is equal to or less than the specified value, it is determined that the charge / discharge direction of the storage battery 5 is likely to be switched due to the deviation variation, and thus the process proceeds to S102.

  In S102, it is determined whether or not the absolute value of the change rate of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the limit value. Here, when it is determined that the absolute value of the change speed is equal to or less than the limit value, it is determined that there is no particular need to suppress the deviation variation, and thus the process proceeds to S104. On the other hand, if it is determined that the absolute value of the change speed is greater than the limit value, it is determined that deviation variation needs to be suppressed, and the process proceeds to S103.

  In S103, a deviation value is output such that the absolute value of the change speed becomes the limit value. On the other hand, in S104, the deviation between the power generation amount and the load amount of the solar cell 2, that is, the input to the rate limiter 760 is output as it is. When the process of S103 or S104 ends, this logic is temporarily ended. In S101 and S102 of FIG. 6, for the sake of simplicity, the terms deviation and change speed are used, but these represent the absolute value of deviation and the absolute value of change speed, respectively. The rate limiter control logic in this embodiment or the CPU 76 that executes the rate limiter control logic corresponds to charge / discharge switching suppression means.

  FIG. 7 shows a block diagram relating to control contents in the present embodiment. The difference between the block diagram shown in the present embodiment and the block diagram shown in FIG. 4 is that, in the present embodiment, the path for operating the rate limiter 760 against the deviation between the power generation amount and the load amount of the solar cell 2; A route that does not work is provided, and a rate limiter control logic 761 that selects which route is used is provided. Whether the deviation between the power generation amount and the load amount of the solar cell 2 makes the rate limiter 760 work depending on whether the rate limiter control logic 761 executes the process of S103 or the process of S104 in the flowchart shown in FIG. No is selected.

  FIG. 8 shows the relationship between the deviation between the power generation amount and the load amount of the solar cell 2 and the deviation output after the deviation fluctuation suppression control by the rate limiter control logic 761 and the rate limiter 760 in this embodiment. . A curve indicated by a dotted line is a deviation between the power generation amount and the load amount of the solar cell 2. A curve indicated by a solid line is a deviation output after the deviation variation suppression control by the rate limiter control logic 761 and the rate limiter 760 is performed. In FIG. 8, the prescribed value of the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2, that is, the threshold value for determining whether or not to operate the rate limiter 760 is set to 5. Further, the limit value of the absolute value of the change speed when the rate limiter 760 is operated is set to 1. Therefore, the deviation between the power generation amount and the load amount of the solar cell 2 indicated by the dotted line is in the range of −5 to +5, and the change from the deviation output of the rate limiter 760 at that time to the deviation amount at the next sampling time. When the absolute value of the speed is greater than 1, the change speed, that is, the absolute value of the slope of the graph is limited to 1.

  According to the dynamic rate limiter described above, the variation in deviation is suppressed only in a region where the deviation between the power generation amount and the load amount of the solar cell 2 is highly likely to switch the charge / discharge direction of the solar cell 2. When the rate limiter is used, that is, compared with the case where all deviation fluctuations are suppressed, the followability of the output of the storage battery 5 with respect to deviation fluctuations in the deviation between the power generation amount and the load amount of the solar battery 2 as a whole can be improved. Therefore, it is possible to maintain the FRR related to the combination of the solar cell 2 and the storage battery 5 higher than when the rate limiter is used.

Next, in the dynamic rate limiter, the actual specified value regarding the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2, that is, the threshold value of whether or not to operate the rate limiter 760, and the fluctuation speed when the rate limiter 760 is operated. The method of determining the actual limit value will be described. Before describing the dynamic rate limiter, first, how to determine the actual limit value of the fluctuation speed when simply operating the rate limiter 760 will be described.

  FIG. 9 is a graph in which the limit value of the absolute value of the change rate when the rate limiter 760 is simply operated is plotted on the horizontal axis, and the FRR and the number of charge / discharge cycles are plotted on the vertical axis. A solid line indicates the number of charge / discharge cycles, and a broken line indicates FRR. From this graph, when the rate limiter 760 is simply operated, the number of times of charging / discharging can be reduced to some extent and sufficient FRR can be obtained as compared with the case where the limit value of the absolute value of the change rate is not set. It can be seen that the possible limit value is, for example, about 0.5.

  Next, in FIG. 10, regarding the dynamic rate limiter in the present embodiment, the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is plotted on the horizontal axis, and the charge / discharge frequency of the FRR and the solar cell 2 is plotted vertically. A graph taken along the axis is shown. From FIG. 10, it is understood that the value of about 0.25 ≦ specified value ≦ 0.4 may be set when the specified value range in which FRR is 70% or more and the number of times of charging / discharging is 10 times or less is examined. In addition, FIG. 11 shows a graph in which the abscissa indicates the prescribed absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 and the ordinate indicates the charging rate and the discharging rate. Here, since it is desirable that the charging rate and the discharging rate are in the range of 90% to 100%, considering the range of the specified value from FIG. 11, it can be said that a value of about 0 ≦ specified value ≦ 0.25 is preferable. Therefore, it can be seen from the results of FIGS. 10 and 11 that 0.25 may be adopted as the value of the specified value.

  FIG. 12 is a graph in which the limit value of the absolute value of the fluctuation speed when the rate limiter 760 is operated in the dynamic rate limiter is plotted on the horizontal axis, and the FRR and the number of charge / discharge cycles are plotted on the vertical axis. A solid line indicates the number of charge / discharge cycles, and a broken line indicates FRR. In this graph, the specified value is fixed at 0.25. From this graph, the dynamic rate limiter is a limit value that can reduce the number of charge / discharge cycles to some extent and can obtain a sufficient FRR compared with the case where the limit value of the absolute value of the change rate is not set. For example, it can be seen that it may be about 0.01.

  In FIG. 13, the horizontal axis shows the number of times of charging / discharging in 36 patterns including the season, weather, and load (all electrification, combined use of gas, combined use of gas power generation), no limiter, use of the rate limiter, and the dynamic rate limiter according to the present embodiment. The result of having performed simulation about each case of use is shown. A solid line indicates a case where no limiter is used, a dotted line indicates that the rate limiter is used, and a broken line indicates a case where the dynamic rate limiter according to this embodiment is used. As can be seen from FIG. 13, overall, the rate limiter is used compared to the case without the limiter, and the case where the dynamic rate limiter is used compared to the case where the rate limiter is used. However, the number of charge and discharge is improved.

  In FIG. 14, the horizontal axis shows the FRR in 36 patterns including the season, weather, and load (all electrification, combined use of gas, combined use of gas power generation), no limiter, use of the rate limiter, and the dynamic rate limiter according to this embodiment. The result of having performed simulation about each case of use is shown. A solid line indicates a case where no limiter is used, a dotted line indicates that the rate limiter is used, and a broken line indicates a case where the dynamic rate limiter according to this embodiment is used. As can be seen from FIG. 14, overall, the FRR is highest when there is no limiter, but the FRR is higher when the dynamic rate limiter is used than when the rate limiter is used. It is high.

15 to 19 show the deviation between the power generation amount and the load amount of the solar cell 2 and the charge of the storage battery 5 for each case of no limiter, use of the rate limiter, and use of the dynamic rate limiter according to the present embodiment in each environmental condition. The measurement result of electric discharge and receiving end trading power is shown. 15 shows the case of spring rain, FIG. 16 shows the case of sunny summer, FIG. 17 shows the case of summer rain, FIG. 18 shows the case of autumn rain, and FIG. 19 shows the case of cloudy winter season. In all cases of measurement under five kinds of environmental conditions, FRR has no limiter, FRR is high in the order of using the dynamic rate limiter according to this embodiment, and using the rate limiter. It can be seen that the number of times of charging and discharging is small in the order of using the dynamic rate limiter according to the example and without the limiter.

  As a result of the above, it was understood that it is effective to use the dynamic rate limiter in the present embodiment as a method for obtaining a relatively small number of charge / discharge cycles and a relatively high FRR in a balanced manner.

<Example 2>
Next, a second embodiment of the present invention will be described. In this embodiment, there are a plurality of prescribed values of absolute values of deviation between the power generation amount and the load amount of the solar battery 2, and a multi-stage limit value for the absolute value of the change rate is set in multiple steps according to the deviation value. The level dynamic rate limiter will be described. In addition, the system configuration | structure of the solar power generation system 1 and the control apparatus 7 in a present Example is the same as that of the Example 1 shown in FIG.1 and FIG.2.

  On the premise that the dynamic rate limiter in Example 1 is used, if the number of charge / discharge is further reduced, the amount of FRR decrease becomes large, and the number of charge / discharge is larger than that shown in Example 1. It was not easy to reduce. On the other hand, in this embodiment, the second specified value in a wider range is set with respect to the specified value range set in the first embodiment, and the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is the specified value. If it is greater than or equal to the second specified value, a second limit value larger than the limit value in the first embodiment is set for the change rate of the deviation, and the deviation between the power generation amount of the solar cell 2 and the load amount is set. It was decided to limit the rate of change. In the following description, this control is called a multilevel dynamic rate limiter.

  FIG. 20 shows a flowchart of the rate limiter control logic 2 for suppressing deviation fluctuation by the multi-level dynamic rate limiter in the present embodiment. The rate limiter control logic 2 is also a program stored in the ROM 77 of the control device 7 and is executed by the CPU 76.

  When this logic is executed, first, in S201, it is determined whether or not the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the specified value 1. The specified value 1 here corresponds to the specified value in the dynamic rate limiter. When it is determined that the absolute value of the deviation is larger than the specified value 1, it is determined that the possibility of switching the charge / discharge direction of the storage battery 5 due to the deviation variation is low, and the process proceeds to S205. On the other hand, when it is determined in S101 that the absolute value of the deviation is equal to or less than the specified value, it is determined that there is a high possibility that the charge / discharge direction of the storage battery 5 is switched due to the deviation variation, and thus the process proceeds to S202.

  In S202, it is determined whether or not the absolute value of the change rate of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the limit value 1. The limit value 1 here is equivalent to the limit value in the dynamic rate limiter. If it is determined that the absolute value of the change speed is equal to or less than the limit value 1, it is determined that there is no need to suppress the deviation variation, and the process proceeds to S204. On the other hand, if it is determined that the absolute value of the change speed is greater than the limit value 1, it is determined that deviation variation needs to be suppressed, and the process proceeds to S203.

  In S203, a deviation output is calculated such that the absolute value of the change speed becomes the limit value 1, and the value is output. On the other hand, in S204, the deviation between the power generation amount and the load amount of the solar cell 2 is output as it is.

  Next, in S205, it is determined whether or not the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the specified value 2. The specified value 1 and the specified value 2 are positive numbers, and the specified value 2 is set to be larger than the specified value 1. Here, when it is determined that the absolute value of the deviation is larger than the specified value 2, it is determined that the possibility of switching the charge / discharge direction of the storage battery 5 due to the deviation variation is lower, and thus the process proceeds to S209. On the other hand, when it is determined in S205 that the absolute value of the deviation is equal to or less than the specified value 2, it is determined that there is a possibility that the charge / discharge direction of the storage battery 5 is switched due to the deviation fluctuation, and thus the process proceeds to S206. .

  In S206, it is determined whether or not the absolute value of the change rate of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the limit value 2. The limit value 1 and the limit value 2 are positive numbers, and the limit value 2 is set to be larger than the limit value 1. Here, if it is determined that the absolute value of the change speed is equal to or less than the limit value 2, it is determined that there is no particular need to suppress the deviation fluctuation, and the process proceeds to S208. On the other hand, if it is determined that the absolute value of the change speed is greater than the limit value 2, it is determined that deviation variation needs to be suppressed, and the process proceeds to S207.

  In S207, a deviation output is calculated such that the absolute value of the change speed is the limit value 2, and the value is output. On the other hand, in S208, the deviation value between the power generation amount and the load amount of the solar cell 2 is output as it is. When any one of S203, S204, S207, and S208 is completed, this flow is temporarily ended.

  A multi-level dynamic rate limiter having two levels of default values and limit values is realized by the flow of S201 to S208. Similarly, when three or more levels of specified values and limit values are set, S205 to The process corresponding to S208 is repeated. Here, a case where there are n-stage specified values and limit values will be described as processing after S209. In S209, it is determined whether or not the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than a specified value n. Here, when it is determined that the absolute value of the deviation is larger than the specified value n, it is determined that the possibility of switching the charge / discharge direction of the storage battery 5 due to the deviation variation is further low, and thus the process proceeds to S212. On the other hand, when it is determined in S209 that the absolute value of the deviation is equal to or less than the specified value n, it is determined that there is still a possibility that the charge / discharge direction of the storage battery 5 is switched due to the deviation fluctuation. Proceed to S210.

  In S210, it is determined whether the absolute value of the change rate of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the nth limit value. Here, when it is determined that the absolute value of the change speed is equal to or less than the nth limit value, it is determined that there is no need to suppress the deviation variation, and the process proceeds to S212. On the other hand, if it is determined that the absolute value of the change speed is larger than the nth limit value, it is determined that deviation variation needs to be suppressed, and the process proceeds to S211.

  In S211, a deviation output is calculated such that the absolute value of the change speed becomes the limit value n, and the value is output. On the other hand, in S212, the deviation between the power generation amount and the load amount of the solar cell 2 is output as it is. When the process of S211 or S212 ends, this flow is temporarily ended. In S201, S205, and S209 of FIG. 20, the word “deviation” is used for simplicity, and these mean the absolute value of the deviation. Also, in S202, 206, and 210, the term "change speed" is used for simplicity, but these mean the absolute values of the change speed. Further, the rate limiter control logic 2 or the CPU 76 that executes the rate limiter control logic 2 in this embodiment corresponds to charge / discharge switching suppression means.

FIG. 21 is a block diagram relating to the control contents of the multilevel dynamic rate limiter in the present embodiment. The difference between the block diagram shown in the present embodiment and the block diagram shown in FIG. 7 is that a ray limiter 760 and a rate limiter 762 are different in this embodiment.
This is a point having two types of rate limiters. The rate limiter 760 uses the specified value 1 and the limit value 1 for control, whereas the rate limiter 762 uses the specified value 2 and the limit value 2 for control. In this embodiment, the rate limiter control logic 761 selects which rate limiter is to be activated or which rate limiter is not to be activated in accordance with the deviation between the power generation amount and the load amount of the solar cell 2. In addition, in the case where there are n-stage specified values and limit values, n rate limiters are provided in FIG.

  FIG. 22 shows the relationship between the deviation between the power generation amount and the load amount of the solar cell 2 and the deviation output after the deviation fluctuation suppression control by the multi-level dynamic rate limiter is performed in this example. The horizontal axis is time and the vertical axis is power, but the numerical value itself is for convenience. In FIG. 22, the prescribed value of the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is set to 5 as indicated by a broken line, and the prescribed value 2 is set to 15 as indicated by a dotted line. Further, the limit value of the absolute value of the change speed is set to 1 and the limit value 2 is set to 5. Therefore, the deviation between the power generation amount and the load amount of the solar cell 2 indicated by the dotted broken line is in the range of -5 to +5 (the absolute value of the deviation is 5 or less), and from the deviation output of the rate limiter at that time point, When the absolute value of the rate of change to the next deviation amount is greater than 1, the absolute value of the rate of change (the slope of the graph) is limited to 1. Further, the deviation between the power generation amount and the load amount of the solar cell 2 indicated by the dotted broken line is in the range of -15 to -5 and +5 to +15, and the deviation from the deviation output of the rate limiter at that time is When the absolute value of the rate of change to quantity is greater than 5, the absolute value of the rate of change (slope of the graph) is limited to 5.

  According to this, when the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 that is likely to change the charge / discharge direction of the solar cell 2 is small, the deviation variation is more severely suppressed. As the absolute value of the deviation between the power generation amount and the load amount of the battery 2 increases, the control for relaxing the deviation fluctuation can be realized, so that the charging can be performed more reliably than when the dynamic rate limiter is used. It is possible to reduce the number of discharges.

  Next, how to set the specified value 2 and the limit value 2 in the multilevel dynamic rate limiter in this embodiment will be described. At this time, the specified value 1 of the deviation range at the first stage is set to 0.25 as in the first embodiment. The limit value 1 is also set to 0.01 as in the first embodiment. FIG. 23 shows a graph in which the horizontal axis represents the limit value 2 in the second stage deviation range, and the vertical axis represents FRR and the number of charge / discharge cycles. In FIG. 23, it can be seen that a value of 0.4 may be selected as the limit value 2 that can be realized by combining a small number of charge / discharge cycles and a high FRR. At this time, the specified value 2 is temporarily fixed to 0.8.

  Next, FIG. 24 shows a graph in which when the limit value 2 is 0.4, the abscissa indicates the specified value 2 and the ordinate indicates the FRR and the number of charge / discharge cycles. In FIG. 24, it can be seen that a value of 0.75 may be selected as the limit value 2 that can be realized by combining a low number of charge / discharge cycles and a high FRR.

  Next, after setting the specified value to 0.25, the limit value to 0.01, the specified value 2 to 0.75, and the limit value 2 to 0.4, the FRR when the multi-level dynamic rate limiter is used is When the number of times of charging / discharging was determined by simulation, the FRR was 77% and the number of times of charging / discharging was 4. On the other hand, in order to suppress the number of times of charging / discharging to 4 times using the dynamic rate limiter shown in Example 1, it is necessary that the specified value is 0.75 and the limit value is 0.02. When the simulation was performed using the limit value, the FRR was 52%. As described above, when the multi-level dynamic rate limiter in the present embodiment is used, a higher FRR can be obtained when the same number of times of charging and discharging is used as compared with the case of using the dynamic rate limiter in the first embodiment. Is possible.

In FIG. 25, the horizontal axis shows the number of times of charging / discharging in 36 patterns including the season, weather, and load (all electrification, combined use of gas, combined use of gas power generation) when the dynamic rate limiter is used, and the multi-rate according to this embodiment. The result of having performed simulation about the case where a level dynamic rate limiter is used is shown. A solid line indicates a case where the dynamic rate limiter is used, and a dotted line indicates a case where the multi-level dynamic rate limiter according to the present embodiment is used. Here, the limit value of the dynamic rate limiter is 0.01, the specified value is 0.25, the limit value of the multi-level dynamic rate limiter is 0.2, the specified value is 0.35, and the limit value 2 is 0.01. The value 2 is 0.25.

  As can be seen from FIG. 25, it can be seen that the number of charge / discharge cycles is improved when the multi-level dynamic rate limiter is used as compared with the case where the dynamic rate limiter is used. The average number of times of charging / discharging was 16 times when the dynamic rate limiter was used, and 14 times when the multi-level dynamic rate limiter was used.

  FIG. 26 also shows the FRR in 36 patterns including the season, weather, and load (all electrification, combined use of gas, combined use of gas power generation) on the horizontal axis when the dynamic rate limiter is used and the multi-rate according to this embodiment. The result of having performed simulation about the case where a level dynamic rate limiter is used is shown. A solid line indicates a case where the dynamic rate limiter is used, and a dotted line indicates a case where the multi-level dynamic rate limiter according to the present embodiment is used. As can be seen from FIG. 26, overall, it can be seen that the same FRR was obtained when the dynamic rate limiter was used and when the multi-level dynamic rate limiter was used. The average value of FRR was 85% in both cases.

  In Examples 1 and 2 described above, the deviation between the power generation amount and the load amount of the solar cell 2 is divided into a plurality of regions, and different specified values and limit values are used in each region. Control was performed so that the variation in the deviation between the power generation amount and the load amount did not cross the zero deviation line. However, instead of such stepwise control, a limit value determined in a stepless manner is read from a map prepared in advance according to the deviation between the power generation amount and the load amount of the solar cell 2, and the solar cell 2 The smaller the absolute value of the deviation between the power generation amount and the load amount, the smaller the limit value may be used for control.

  According to this, as the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is smaller, the absolute value of the change rate of the deviation can be finely reduced, and the power generation of the solar cell 2 can be performed more reliably. It is possible to prevent the variation in the deviation between the quantity and the load quantity from intersecting the zero deviation line.

<Example 3>
Next, Embodiment 3 of the present invention will be described. In this embodiment, the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is not more than a specified value, and the absolute value of the change rate of the deviation is not more than the limit value, and the deviation is A directional dynamic rate limiter that limits the change rate of the deviation when the charge / discharge direction is changed will be described. In addition, the system configuration | structure of the solar power generation system 1 and the control apparatus 7 in a present Example is the same as that of the Example 1 shown in FIG.1 and FIG.2.

  FIG. 27 shows a flowchart of the rate limiter control logic 3 for suppressing deviation variation by the directional dynamic rate limiter in this embodiment. The rate limiter control logic 3 is also a program stored in the ROM 77 of the control device 7 and is executed by the CPU 76.

When this logic is executed, first, in S301, it is determined whether or not the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than a specified value. Here, when it is determined that the absolute value of the deviation is larger than the specified value, it is determined that the possibility of switching the charge / discharge direction of the storage battery 5 due to the deviation variation is low, so the process proceeds to S305. On the other hand, if it is determined in S301 that the absolute value of the deviation is equal to or less than the specified value, it is determined that there is a high possibility that the charge / discharge direction of the storage battery 5 is switched due to the deviation variation, and the process proceeds to S302.

  In S302, it is determined whether or not the absolute value of the change rate of the deviation between the power generation amount and the load amount of the solar cell 2 is equal to or less than the limit value. Here, if it is determined that the absolute value of the change speed is equal to or less than the limit value, it is determined that there is no particular need to suppress the deviation variation, and thus the process proceeds to S305. On the other hand, if it is determined that the absolute value of the change speed is greater than the limit value, it is determined that deviation variation needs to be suppressed, and the process proceeds to S303.

  In S303, it is determined whether or not the deviation after the change is a deviation that changes the charging / discharging direction of the storage battery 5. That is, it is determined whether the deviation output curve is a deviation that intersects a line with a charge / discharge amount of zero. Here, when the deviation after the change is not a deviation that changes the charging / discharging direction of the storage battery 5, it is determined that it is not always necessary to suppress the deviation fluctuation, and the process proceeds to S305. On the other hand, when it is determined that the deviation after the change is a deviation that changes the charging / discharging direction of the storage battery 5, it is determined that the deviation fluctuation needs to be suppressed, and the process proceeds to S304.

  In S304, a deviation output is calculated so that the absolute value of the change speed becomes the limit value, and this value is output. On the other hand, in S305, the deviation between the power generation amount and the load amount of the solar cell 2 is output as it is. The content of the block diagram related to the control content in this embodiment is the same as the block diagram shown in FIG. The rate limiter control logic 3 or the CPU 76 that executes the rate limiter control logic 3 in this embodiment corresponds to charge / discharge switching suppression means. In particular, the process of S303 in the rate limiter control logic 3 or the CPU 76 that executes the process of S303 corresponds to charge / discharge switching determination means.

  FIG. 28 shows the relationship between the deviation between the power generation amount and the load amount of the solar cell 2 and the deviation output when the directional dynamic rate limiter is used in this example. The horizontal axis represents time and the vertical axis represents power, but the numerical value itself is for convenience. In FIG. 28, the prescribed value of the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 is set to 5. Further, the limit value of the absolute value of the change speed is set to 1. Accordingly, the deviation between the power generation amount and the load amount of the solar cell 2 indicated by the dotted line is in the range of −5 to +5, and the absolute value of the rate of change to the next deviation amount is greater than 1, and further, at that time When the change from the deviation output of the directional dynamic limiter crosses the line with zero deviation, the absolute value of the change speed (the slope of the graph) is limited to one.

  According to this, since the deviation fluctuation is suppressed only when the charging / discharging direction of the solar battery 2 is actually switched, the storage battery 5 with respect to the deviation fluctuation of the deviation between the power generation amount and the load amount of the solar battery 2 as a whole. Therefore, the FRR in the combination of the solar cell 2 and the storage battery 5 can be maintained higher.

<Example 4>
Next, a fourth embodiment of the present invention will be described. In this embodiment, a limited directional dynamic rate limiter obtained by further improving the directional dynamic rate limiter described in the third embodiment will be described. In addition, the system configuration | structure of the solar power generation system 1 and the control apparatus 7 in a present Example is the same as that of the Example 1 shown in FIG.1 and FIG.2.

In the limited directional dynamic rate limiter in the present embodiment, as shown in FIG. 29, the rate of change in the deviation between the power generation amount and the load amount of the solar cell 2 is limited according to the following rules.
(1) The deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time and the deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time have the same sign, and the absolute value increases. In the case of a change in direction, the rate of change is not limited.
(2) The absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time is not more than the specified value 3, and the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time; When the deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time has the same sign and is a fluctuation in a direction in which the absolute value decreases, the change speed is limited to the limit value 3.
(3) The absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time is not more than the specified value 3, and the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time; The deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time is an opposite sign, and the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time is equal to or less than the specified value 4. Limits the rate of change to a limit value of 3.
(4) The absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time is not more than the specified value 3, and the deviation between the power generation amount and the load amount of the solar cell 2 at the current sampling time; The deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time is an opposite sign, and the absolute value of the deviation between the power generation amount and the load amount of the solar cell 2 at the next sampling time is larger than the specified value 4. Does not limit the rate of change.

  FIG. 30 shows the relationship between the deviation between the power generation amount and the load amount of the solar cell 2 and the deviation output when the directional dynamic rate limiter described in the third embodiment is used. FIG. 31 shows the relationship between the deviation between the power generation amount and the load amount of the solar cell 2 and the deviation output when the limited directional dynamic rate limiter in this embodiment is used.

  As is clear when comparing the latter half of the graphs of FIG. 30 and FIG. 31, when the limited directional dynamic rate limiter is used in this embodiment, for example, the charge / discharge direction of the storage battery 5 is switched. Even if the variation of the deviation is not large, the variation rate is not limited if the variation is large. Therefore, the change rate is not limited for the fluctuation that greatly affects the FRR in the combination of the solar battery 2 and the storage battery 5, and the FRR in the combination of the solar battery 2 and the storage battery 5 can be kept high.

  In the above embodiment, the example in which the present invention is applied to the solar power generation system 1 shown in FIG. 1 has been described. However, the solar power generation system to which the present invention is applied is not limited thereto. You may apply to the solar power generation system 10 as shown in FIG. In this solar power generation system 10, the storage battery 5 is connected to the bidirectional DC / AC conversion circuit 16, and the output of the bidirectional DC / AC conversion circuit 16 is connected to the output of the bidirectional DC / AC conversion circuit 4. Has been. Thereby, the solar power generation system 10 can exhibit functions equivalent to the solar power generation system 1.

  In FIG. 32, a range indicated by a broken line, that is, the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, the control device 7, and the bidirectional DC / AC conversion circuit 16 are arranged in one housing in the form of a power conditioner 10a. You may arrange. Alternatively, only the control device 7 is an independent device, and a range indicated by a dotted line, that is, the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, and the bidirectional DC / AC conversion circuit 16 are in the form of a power conditioner 10b. You may arrange | position in one housing | casing. Here, at least one of the DC / DC conversion circuit 3, the bidirectional DC / AC conversion circuit 4, and the bidirectional DC / AC conversion circuit 16 corresponds to the power conversion device in the present embodiment.

In the above embodiment, the control for reducing the frequency of switching between the state in which the storage battery is discharged and the state in which the storage battery is charged is controlled by cooperation between the software (program) stored in the ROM 77 of the control device 7 and the CPU 76. Although an example realized by operation has been described, there is no problem even if the control of the present invention is realized using an analog circuit.

DESCRIPTION OF SYMBOLS 1 ... Photovoltaic power generation system 1a, 1b ... Power conditioner 2 ... Solar cell 3 ... DC / DC conversion circuit 4 ... Bidirectional DC / AC conversion circuit 5 ... Storage battery 6. .... Bidirectional DC / DC conversion circuit 7 ... Control device 10 ... Solar power generation system 10a, 10b ... Power conditioner 16 ... Bidirectional DC / AC conversion circuit 760, 762 ... Late Limiter 761 ... Late limiter control logic

Claims (13)

Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A control device for a distributed power supply system comprising:
When the amount of power generated by the power generation means is insufficient with respect to the amount of power load, the power generation amount by the power generation means is supplemented with the amount of power generated by the power generation means by discharging from the storage battery according to the shortage. Control means for charging the storage battery with electric power corresponding to the surplus amount when the load amount is larger than the load amount;
Fluctuation suppression means for converting the deviation value between the power generation amount of the power generation means and the power load amount so that the fluctuation is suppressed;
When the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is smaller than the case where the absolute value of the deviation is larger, the power generation amount of the power generation means by the fluctuation suppression means Charge / discharge switching suppression that reduces the frequency at which the state of discharging from the storage battery and the state of charging of the storage battery are switched by the control means by increasing the degree of suppression of variation in deviation from the power load amount Means
A control device for a distributed power supply system, comprising:   The charge / discharge switching suppression means has one or a plurality of threshold values for the deviation between the power generation amount of the power generation means and the power load amount, and the absolute value of the deviation between the power generation amount of the power generation means and the power load amount, Based on the relationship with the threshold value, the deviation is divided into a plurality of areas corresponding to the magnitude of the absolute value of the deviation, and the absolute value of the deviation is larger in an area where the absolute value of the deviation is smaller. Compared to the region, the fluctuation suppressing means is connected to the power generation amount and the power load amount of the power generation means so that the change rate of the deviation between the power generation amount and the power load amount of the power generation means becomes a smaller value. The control apparatus for a distributed power supply system according to claim 1, wherein the deviation is converted.   The charge / discharge switching suppressing means is configured to determine the deviation based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and a predetermined threshold value, and a first region in which the absolute value of the deviation is smaller. And when the deviation belongs to the first region, the deviation between the power generation amount of the power generation unit and the power load amount is given to the fluctuation suppression unit. 3. The control device for a distributed power supply system according to claim 1, wherein the conversion is performed so that the rate of change is suppressed. The charge / discharge switching suppression means determines whether the variation in the deviation between the power generation amount of the power generation means and the power load is a change in which the state of discharging from the storage battery and the state of charging the storage battery are switched. Having charge / discharge switching judging means for judging,
The charge / discharge switching determination means determines that the variation in the deviation between the power generation amount and the power load amount of the power generation means is a change in which the state of discharging from the storage battery and the state of charging the storage battery are switched. 4. The method according to claim 2, wherein the fluctuation suppression unit converts the deviation between the power generation amount of the power generation unit and the power load amount so that the rate of change is suppressed. Control device for distributed power system.   5. The control of the distributed power supply system according to claim 1, wherein the power generation unit is a solar power generation unit configured to generate power by converting solar energy into electric power using a solar cell. apparatus. A control device according to any one of claims 1 to 5;
A power conversion device that performs voltage conversion and / or DC / AC conversion of each output between at least one of the power generation means and the storage battery and at least one of a power load and a system;
A power conditioner for a distributed power supply system. A control device according to any one of claims 1 to 5;
Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A distributed power supply system comprising: A power conditioner according to claim 6;
Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged in accordance with a deviation between an electric power generation amount of the electric power generation means and an electric power load amount;
A distributed power supply system comprising: Power generation means for outputting electric power;
A storage battery that stores electric power and is charged or discharged according to a deviation between an electric power generation amount and an electric power load amount of the electric power generation means,
With the amount of power generation to supplement power generation amount by the power generating means and discharged from said storage battery in response to said non foot amount if missing to power load amount by the power generating means, the power generation amount by the power generating means power When there is more than the load amount, the storage battery is charged with electric power according to the surplus amount, and the control method of the distributed power system,
When the absolute value of the deviation between the power generation amount of the power generation means and the power load amount is smaller, the deviation between the power generation amount of the power generation means and the power load amount than when the absolute value of the deviation is larger. The frequency of switching the value so that the fluctuation is suppressed more greatly, thereby reducing the frequency of switching between the state of discharging from the storage battery and the state of charging the storage battery, Power system control method.
  Based on the relationship between the absolute value of the deviation between the power generation amount of the power generation means and the power load amount and one or more thresholds, the deviation is a plurality of areas corresponding to the magnitude of the absolute value of the deviation. In the region where the absolute value of the deviation is smaller, the change rate of the deviation between the power generation amount of the power generation means and the power load amount is smaller than in the region where the absolute value of the deviation is larger. The method of controlling a distributed power system according to claim 9, wherein a deviation between the power generation amount of the power generation means and the power load amount is converted so as to be a value.   Based on the relationship between the absolute value of the deviation between the power generation amount and the power load amount of the power generation means and a predetermined threshold, the deviation is defined as a first region where the absolute value of the deviation is smaller, and the absolute value of the deviation is When the deviation belongs to the first region, the deviation between the power generation amount of the power generation means and the power load amount is converted so that the rate of change is suppressed. The control method of the distributed power supply system according to claim 9 or 10, characterized in that   When it is determined that the variation in the deviation between the power generation amount of the power generation means and the power load amount is a change in which the state of discharging from the storage battery and the state of charging the storage battery are switched, The method of controlling a distributed power system according to claim 10 or 11, wherein the deviation between the power generation amount and the power load amount is converted so that the rate of change is suppressed.   The distributed power system according to any one of claims 9 to 12, wherein the power generation means is a solar power generation means that generates power by converting solar energy into electric power by a solar cell. Control method.

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