JP2011010504A - System for controlling plurality of power supplies, and power conversion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of the entire power supply systems by controlling a plurality of power supplies.SOLUTION: The system 200 for controlling a plurality of power supplies controls each output of the power supplies 300 where the power that can be output is fluctuated by an external factor. The power supplies 300 can increase and decrease the output by a control parameter, and is operated with the control parameter set so that the output becomes close to the maximum. An integrated control unit 100 selects a power supply 300 whose power should be suppressed on the basis of reliability in each power supply when a situation requiring total power suppression results. Then, power is suppressed by a power suppressing method whose load to the power supply 300 is low out of a plurality of kinds of power suppressing methods of the selected power supply 300.

Description

  The present invention relates to a system for controlling a plurality of power supplies.

  With the development of the world economy, especially the economic growth in the Asian region, the demand for energy will continue to increase. For example, the International Energy Agency predicts global primary energy demand in 2030 to be 66% higher than 2000. In such a social situation, expectations for renewable energy such as solar, wind, biomass, geothermal and tidal power are increasing.

  Renewable energy has an excellent characteristic that it is clean and can be used permanently, but it has been pointed out that the output is not stable. For example, a wind power generator is unlikely to be a stable power supply source because its output changes due to the natural phenomenon of wind power. In order to cope with such a problem, a distributed power generation system has been proposed that aims to stabilize power supply by combining a plurality of renewable energy sources such as wind power generation, solar power generation, and solar thermal power generation. (For example, see Patent Documents 1, 2, 3, and 4).

JP 2003-399118 A JP 2005-224209 A Japanese Patent Laid-Open No. 04-372528 JP 2003-343416 A JP 2006-94652 A JP 2003-79057 A JP 2004-088900 A Japanese Patent Laid-Open No. 05-122855 JP 58-095988 A

  Some of the power sources included in the distributed power generation system have a long service life and some are short. In order to stably operate a power distribution type power generation system for a long period of time, it is desirable to reduce a physical load on a power supply having a short service life. Patent Document 6 discloses a power supply system that uses a plurality of micro gas turbines as power generation sources. In patent document 6, when the remaining life of each micro gas turbine is estimated and it is desired to suppress power supply, the micro gas turbine is stopped from the short remaining life.

  Actually, when operating a power distribution type power generation system, it is more realistic to suppress the output of one of the power sources than to stop one of the power sources. The present inventor considered that such a load on the power source can be effectively suppressed by preferentially suppressing power from a power source having a short service life. Furthermore, the present inventor has recognized that even if power is suppressed, the physical load applied to the power supply may increase.

  The present invention is an invention completed based on the above-mentioned problem recognition by the present inventor, and its main object is to provide a system for controlling a plurality of power supplies and realizing a long life as a whole power supply system. There is to do.

  The multiple power supply control system according to the present invention is connected to a plurality of irregular power supplies that are power supplies whose output power varies depending on external factors. The irregular power supply is a power supply that can be controlled to increase or decrease the output by the control parameter and that is operated in a state in which the control parameter is set so that the output is close to the maximum value. This system includes an output control unit that controls the output of each of a plurality of irregular power supplies, a measurement unit that obtains the total power output from a plurality of irregular power supplies in a unit time, and a total power amount that is predetermined. A condition determination unit that determines whether or not an output suppression condition is satisfied, and a power source selection unit that preferentially selects a random power source having low durability among a plurality of irregular power sources when the output suppression condition is satisfied Prepare. The output control unit selects the power suppression method by increasing the value of the control parameter and the power suppression method by decreasing the power control method with the lower influence on the durability of the selected irregular power source. The power output from the irregular power supply is suppressed.

  The “irregular power source” referred to here may be a power source derived from renewable energy, or may be a power source whose output is affected by the outside air temperature, such as a fuel cell. The “plurality of irregular power sources” may be different types of power sources such as solar power generation and wind power generation, or may be the same type of power sources such as solar power generation and solar power generation. The measurement unit may measure the amount of power itself, or may acquire a measurement value from an external sensor. “Select preferentially” means that control is performed such that an irregular power source having lower durability is more easily selected. For example, comprehensive judgment based on not only the durability but also other parameters may be used. The system suppresses power preferentially from a power source having a low durability among a plurality of power sources, and further suppresses power by adopting a power suppression method having the least influence on the durability of the power source among a plurality of power suppression methods. Can be operated stably over a long period of time.

  When the selected irregular power source is a non-single crystal semiconductor solar cell, the output control unit increases the output voltage of the solar cell to decrease the output current of the solar cell, thereby reducing the solar cell based on the non-single crystal semiconductor. You may suppress the electric power output from. According to such a control method, it is easy to suppress a physical load on the crystal structure of the solar cell made of a non-single crystal semiconductor, and thus it is easy to extend the life of the solar cell. Note that a low reliability (a value indicating high durability) is set for a solar cell made of a non-single crystal semiconductor, and such a solar cell is preferentially or reliably targeted for power suppression. You may do it.

  When the selected irregular power source is a wind power generator, the output control unit outputs the wind power generator by reducing the output voltage of the wind power generator and reducing the rotation speed of the wind turbine in the wind power generator. Electric power may be suppressed. According to such a control method, it is easy to suppress a physical load on the bearing portion of the windmill, and thus it is easy to extend the life of the wind power generator. Note that a particularly low reliability may be set for the wind power generator so that the wind power generator is preferentially or reliably targeted for power suppression.

  The system may further include a monitoring unit that monitors the operation state of a plurality of irregular power supplies, and a reliability update unit that updates reliability information according to the operation state of each irregular power source. According to such a control method, the reliability can be dynamically updated according to the operating state of each power supply, and therefore it becomes easy to align the end of use of a plurality of power supplies.

  The system further includes a charge / discharge control unit that controls charging / discharging of a lithium ion battery that is charged by power from a plurality of irregular power supplies, and the condition determination unit sets the charging rate of the lithium ion battery to a predetermined threshold value. When it exceeds, it determines with the output suppression condition having been satisfied, and a charge / discharge control part may discharge a lithium ion battery, when total electric energy is suppressed by establishment of an output suppression condition. By suppressing the total power in consideration of the charging rate of the lithium ion battery, the life of the lithium ion battery can be extended, and as a result, the stable operability of the entire system can be easily improved.

  Another multiple power supply control system according to the present invention is connected to one or more of a plurality of irregular power supplies, which are power supplies whose output power varies depending on external factors, and is common among the power output from the irregular power supplies. A plurality of power conversion devices that control the magnitude of power to be supplied to the power line, and an integrated control device that controls the plurality of power conversion devices. The irregular power supply is a power supply that can be controlled to increase or decrease the output by the control parameter and that is operated in a state in which the control parameter is set so that the output is close to the maximum value. The integrated control device includes a measuring unit that acquires a total power amount per unit time supplied to a common power line from a plurality of irregular power supplies, and a condition that determines whether the total power amount satisfies a predetermined output suppression condition When the judgment unit and output suppression conditions are satisfied, refer to reliability information indicating the high durability of the irregular power supply, and select among the irregular power supplies with low durability among the multiple irregular power supplies. And a suppression instruction unit that transmits an output suppression instruction to the power conversion apparatus that is in charge of controlling the selected irregular power source. The power conversion device includes an output control unit that controls the output of the irregular power source of the connection destination, and a suppression instruction receiving unit that receives a suppression instruction from the integrated control device, and the output control unit receives the suppression instruction The irregularity selected by the power suppression method having the lower influence on the durability of the selected irregular power source among the power suppression method by increasing the value of the control parameter and the power suppression method by decreasing the value. Suppress power output.

  One power converter according to the present invention is connected to an irregular power source, which is a power source that changes output power due to external factors. The apparatus includes an output control unit that controls power to be provided to the common power line among power output from the irregular power source, a reliability information holding unit that holds reliability information indicating durability of the irregular power source, A communication unit that transmits / receives reliability information to / from another power conversion device connected to another irregular power source. When a predetermined output suppression condition is satisfied, the output control unit refers to the reliability information received from the other power conversion device, and is more reliable than the durability of the irregular power source that the other power conversion device is responsible for. When the irregular power supply with which the device is in charge is low, the power suppression method by increasing the control parameter value from the reference point or the power suppression method by decreasing the control parameter value The output of the irregular power supply in charge is suppressed by the power suppression method with the lower impact on durability.

  The apparatus further includes a monitoring unit that monitors an operation state of the irregular power source at the connection destination, and a reliability update unit that updates the reliability information according to the operation state of the irregular power source at the connection destination. Good.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is easy to realize a long life as a whole system by controlling a plurality of power supplies.

It is a figure which shows the structure of the multiple power supply control system in 1st Embodiment. It is a time chart which shows the measurement process and calculation process for adjusting total electric power. It is a functional block diagram of the integrated control apparatus in 1st Embodiment. It is a functional block diagram of the power converter device in a 1st embodiment. FIG. 3 is a circuit diagram of an output control circuit in the first embodiment. It is a graph which shows the current-voltage characteristic of a solar cell. It is a graph which shows the power voltage characteristic of a solar cell. It is a graph which shows the current voltage characteristic of wind power generation. It is a flowchart of the process which suppresses total electric power in 1st Embodiment. It is a hardware block diagram of the multiple power supply control system in 2nd Embodiment. It is a functional block diagram of the power converter device in 2nd Embodiment. It is a flowchart of the process which suppresses total electric power in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, as a first embodiment, a power control system of a type in which an integrated control apparatus controls a plurality of power supplies in an integrated manner will be described. Next, a power control system of a type in which a plurality of power conversion devices autonomously control a plurality of power supplies will be described as a second embodiment. Hereinafter, when the first embodiment and the second embodiment are not particularly distinguished, they are simply referred to as “this embodiment”.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a multiple power supply integration system 200 in the first embodiment. The multiple power supply integrated system 200 is a system that realizes stable power supply from the entire system by controlling a plurality of power supplies. In the case of the figure, the “plurality of power sources” corresponds to the solar cell 302, the wind power generation 304, the biomass 306, and the fuel cell 308 (hereinafter simply referred to as “power source 300” unless otherwise specified). In the meaning of a plurality of power supplies 300, they are also referred to as a power supply group 310. The multiple power supply control system 200 in this embodiment is a distributed power supply system designed for the purpose of supplying power to apartment houses such as homes and condominiums and small villages.

  Each power supply 300 generates power independently without interfering with each other. Solar cell 302, wind power generation 304, biomass 306, and fuel cell 308 are connected to common power line 400 via power conversion devices 312a to 312d (hereinafter simply referred to as “power conversion device 312”), respectively. The power converter 312 controls the amount of power supplied from each power supply 300 to the common power line 400 by a method described later. In the present embodiment, power conversion device 312 and power supply 300 are connected on a one-to-one basis, but may be one-to-many. The common power line 400 is a power line that transmits DC power. The total power (hereinafter referred to as “total power”) supplied from each power source 300 to the common power line 400 is supplied from the common power line 400 to various loads such as electric devices via the inverter 402. All or part of the total power may be sold.

  Integrated control device 100 is connected to a plurality of power conversion devices 312, common power line 400, and battery 404. The integrated control device 100 measures the total power and instructs each power conversion device 312 to perform output control based on the measurement result. When the total power exceeds the demand, the excess battery charges the battery 404. When the total power falls below demand, the battery 404 compensates for the shortage. When the total power exceeds the demand and the charging rate of the battery 404 is high, the integrated control device 100 causes one or more power conversion devices 312 to suppress the supply of power.

  The integrated control apparatus 100 in this embodiment measures total power at 1 minute intervals. “Total power” is the amount of electric power (Ws) generated per second during the measurement time of 1 minute. In other words, it is average power. The integrated control apparatus 100 may measure by itself or may acquire a measurement value from an external sensor. The measurement time length of one minute is merely an example, and the optimal measurement time may be determined based on the performance of the integrated control device 100 and the power supply 300, the operating environment, and the like.

  Within the power supply group 310, there are a power supply 300 with a long service life and a short power supply 300. Each power supply 300 is set with a “reliability” in the range of 0 to 100 as an index value indicating the high durability. The administrator of the multiple power supply control system 200 sets a higher reliability for the power supply 300 having a longer estimated useful life. For example, based on MTTF (Mean Time To Failure) and MTBF (Mean Time Between Failure), the power supply 300 having a larger value may set higher reliability. The reliability value may be determined by experiments or simulations in consideration of the operating conditions of the multiple power supply control system 200.

  The multiple power supply control system 200 is normally expected to operate stably for a long period of 20 years or longer. For this purpose, it is desirable to reduce as much as possible the physical load applied to the power supply 300 with low reliability (hereinafter referred to as “low reliability power supply”). Therefore, in this embodiment, when it is desired to suppress the total power, the power is preferentially suppressed from the low reliability power source. In other words, rest from a low-reliability power source.

  When the predetermined “output suppression condition” is satisfied, the integrated control apparatus 100 instructs the power conversion apparatus 312 in charge of the low-reliability power supply to suppress power. The power conversion device 312 that has received the instruction suppresses the supply power of the corresponding power supply 300 by a method described later. The output suppression condition may be arbitrarily determined as a condition that is satisfied when a situation in which total power is to be suppressed occurs. For example, it may be defined as a condition that is satisfied when the total power exceeds a threshold or when the increase degree of the total power per unit time exceeds the threshold. The output suppression condition may be satisfied when the charging rate of the battery 404 exceeds a threshold or when a power suppression instruction is received from an administrator of the multiple power supply control system 200. Hereinafter, the power supply 300 selected as the power suppression target is referred to as a “suppression target power supply”. In the present embodiment, the power supply 300 having the lowest reliability is selected as the suppression target power supply.

  In addition to the above, the power source 300 may be a power source derived from various renewable energies such as tidal power, geothermal heat, snow and ice heat. Further, not only the power source derived from renewable energy, but also a power source whose output power varies depending on external factors can be controlled by the multiple power source control system 200.

FIG. 2 is a time chart showing a measurement process and a calculation process for adjusting the total power. First, at times t _{0 to} t ₁ , the integrated control device 100 measures total power. This measurement result is called “M1”. In the present embodiment, the measurement period from time t _{0 to} t ₁ is 1 minute. Next, at times t _{1 to} t ₂ , the integrated control apparatus 100 determines whether or not the total power adjustment is necessary based on the measurement result M1, and adjusts the total power. This adjustment process is referred to as “A1”. The term “adjustment” as used herein includes processing such as power suppression and release, charging / discharging of the battery 404, and the like, which will be described in detail later with reference to FIG. After completion of the adjustment process A1, measure the total power again at time _t 2 ~t _3. This measurement result is called “M2”. At times t _{3 to} t ₄ when the measurement is completed, the adjustment process A2 based on the measurement result M2 is executed. In this way, measurement and adjustment of the total power are repeatedly performed.

  FIG. 3 is a functional block diagram of the integrated control apparatus 100 according to the first embodiment. The integrated control apparatus 100 can be realized in hardware by an electronic device such as a CPU of a computer, and is realized in software by a program having a data transmission / reception function. However, in FIG. The functional block realized by those cooperation is drawn. Therefore, these functional blocks can be realized in various forms by a combination of hardware and software. Here, the configuration of each functional block will be mainly described. Specific processing contents will be described in detail after the description of the configuration.

  The integrated control apparatus 100 includes a measurement unit 110, a data processing unit 120, and a reliability information holding unit 140. The measuring unit 110 measures the total power. The data processing unit 120 executes various data processing based on data acquired from the measurement unit 110 and the reliability information holding unit 140. The data processing unit 120 also serves as an interface between the measurement unit 110 and the reliability information holding unit 140. The reliability information holding unit 140 is a storage area for holding reliability information in which the reliability of each power supply 300 is registered.

  The data processing unit 120 includes a condition determination unit 122, a power supply selection unit 124, a reliability update unit 126, a power supply control unit 130, and a charge / discharge control unit 136. The condition determination unit 122 determines whether the output suppression condition is successful. The power source selection unit 124 selects the power source to be suppressed with reference to the reliability information when the output suppression condition is satisfied. In the first embodiment, the power supply 300 having the lowest reliability is selected as the suppression target power supply.

  The power supply control unit 130 controls the amount of power supplied from the power supply 300 via the power conversion device 312. The power supply control unit 130 includes an instruction unit 132 and a monitoring unit 134. When the output suppression condition is satisfied, the instruction unit 132 instructs the power conversion device 312 in charge of the suppression target power supply to suppress power. When the output suppression condition returns from the established state to the unestablished state, the power suppression of the suppression target power supply is released. The monitoring unit 134 receives operation information of each power supply 300 via the power conversion device 312. The operation information may be numerical information that quantitatively indicates the accumulated load on the power supply 300. For example, the operation information may include an integrated value of power supplied from the power supply 300, an integrated value of output current, a total operating time, and the like. In the case of wind power generation 304, the total number of rotations of the windmill may be included in the operation information. By receiving the operation information, the monitoring unit 134 monitors the operation state of each power supply 300. The reliability update unit 126 updates the reliability information based on the operation information. For example, the reliability may be decreased by one each time a certain power supply 300 supplies an amount of power for 100,000 (kWh). The algorithm by which the reliability update unit 126 updates the reliability may be determined by experiments, simulations, or the like based on the performance of the power supply 300, the usage environment, or the like, but in any case, the cumulative load on the power supply 300 increases. It is preferable to reduce the reliability.

  Note that the integrated control device 100 and the power conversion device 312 may transmit and receive various types of data such as reliability information and operation information through a dedicated communication line or a wireless system, or may be superimposed on an electric power system such as the common power line 400 as an AC signal. You may send and receive by doing.

  The charge / discharge control unit 136 controls charge / discharge of the battery 404. The battery 404 in this embodiment is a lithium ion battery. When the total power exceeds the demand, the battery 404 is charged with surplus power. On the other hand, when the total power falls below the demand, the shortage is discharged from the battery 404 to the common power line 400. In general, the lithium ion battery is preferably used at a charging rate of 50% to 80%. A lithium ion battery with a charging rate of 100% is not preferable because metallic lithium may be deposited on the negative electrode side. Therefore, the condition determination unit 122 determines that the output suppression condition is satisfied even when the charging rate of the battery 404 exceeds a predetermined threshold, for example, 75%, and suppresses the total power. At this time, the charge / discharge control unit 136 compensates for the suppression by discharging from the battery 404. With such a processing method, not only the power supply 300 but also the battery 404 is extended in life.

  FIG. 4 is a functional block diagram of the power conversion device 312 in the first embodiment. The power conversion device 312 can also be realized by various electronic circuit elements in terms of hardware, and can be realized in terms of software by a program having a data transmission / reception function. FIG. 4 also shows functional blocks realized by their cooperation. I'm drawing. Therefore, these functional blocks can also be realized in various forms by a combination of hardware and software.

  The power conversion device 312 includes an output control unit 320, an instruction reception unit 322, and an operation information transmission unit 324. The output control unit 320 includes a step-up chopper circuit, which will be described later with reference to FIG. 5, and increases or decreases the supplied power by controlling the input impedance. The instruction receiving unit 322 receives various instructions such as a suppression instruction from the instruction unit 132 of the integrated control apparatus 100. When receiving the suppression instruction, the output control unit 320 suppresses the power supplied from the power source 300 to the common power line 400. The operation information transmission unit 324 acquires operation information and transmits it to the integrated control apparatus 100.

FIG. 5 is a circuit diagram of the output control circuit 330 in the first embodiment. The output control circuit 330 is a typical step-up chopper circuit having four terminals of two input terminals P ₁ and P ₂ and two output terminals P ₃ and P ₄ . A power supply 300 is connected to the input terminals P ₁ and P ₂ , and a common power line 400 is connected to the output terminals P ₃ and P ₄ . Inductor L and the diode D is inserted in series in the path from the input terminal P ₁ to the output terminal P _3. The intermediate point P ₅ of the inductor L and the diode D, the transistor Tr is connected between the intermediate point P ₆ of the input terminal P ₂ and the output terminal P _4. Transistor Tr, since the on-off are periodically repeated, the path from the intermediate point P ₅ to the intermediate point P ₆ becomes periodically conductive and non-conductive. A diode D and the intermediate point P ₇ of the output terminal P _3, the capacitor C is connected between the intermediate point P ₆ and the intermediate point P ₈ output terminals P _4.

Assuming that the voltage between the input terminals P ₁ and P ₂ is the input voltage V _in and the current flowing into the input terminal P ₁ is the input current I _in , the input impedance Z _in viewed from the power supply 300 is Z _in = V _in / I _in Is defined as A voltage between the output terminals P ₃ and P ₄ is an output voltage V _out , and a current flowing _{out from} the output terminal P ₃ is an output current I _out . By controlling the timing of on and off of the transistor Tr, the input impedance Z _in is changed. For this reason, the output voltage _Vout and the output current _Iout also vary depending on the duty ratio of the transistor Tr.

When the power-on time of transistor Tr increases, the input impedance _{Z in} is reduced, the output voltage _{V out} decreases, the output current _{I out} is increased. When the power-on time of transistor Tr is small, the input impedance _{Z in} is increased, the output voltage _{V out} increases, the output current _{I out} decreases. By controlling the input impedance Z _in of the output control circuit 330 according to the duty ratio of the transistor Tr, the operating state of the power supply 300 can be controlled.

  Next, the power suppression method will be described for each of the solar cell 302 and the wind power generation 304.

(1) Solar cell FIG. 6 is a graph showing current-voltage characteristics of a solar cell. In the figure, the horizontal axis represents the output voltage V _out and the vertical axis represents the output current I _out . In the solar cell, the output current _Iout becomes maximum when the output voltage _Vout becomes minimum. When the output voltage _Vout is increased by adjusting the input impedance, the output current _Iout gradually decreases. Since the power supplied from the power supply 300 is represented by the product of the output voltage _Vout and the output current _Iout , the magnitude of the power can be adjusted by adjusting the output current _Iout and the output voltage _Vout as control parameters. More specifically, the power is adjusted using the duty ratio of the transistor Tr in the output control circuit 330 as a control parameter. When the current-voltage characteristic of the solar cell is represented by the graph G1, the power becomes maximum at a point S (output current I _out = Is, output voltage V _out = Vs) in the same figure. Hereinafter, the point S is referred to as a “reference point”. When sunlight becomes strong, the current-voltage characteristic becomes as shown in the graph G3, and the power that can be output increases. On the contrary, when sunlight becomes weak, the current-voltage characteristic becomes as shown in the graph G2, and the power that can be output becomes small. In any case, the power conversion device 312a having jurisdiction over the solar cell 302 sets a control parameter at the reference point S at which the power is maximum under the given sunshine conditions.

Solar cells include single crystal semiconductor solar cells and non-single crystal semiconductor solar cells. A single crystal semiconductor solar cell using single crystal silicon or the like has a merit that it has a long service life, but has a high cost. Non-single-crystal semiconductor solar cells using polycrystalline silicon, amorphous silicon, or the like have a merit of low cost, but are inferior to single-crystal semiconductor solar cells in terms of durability. This is because the movement of carriers during power generation damages the crystal structure of the solar cell. In the case of the polycrystalline type, crystal defects at the grain boundaries are promoted by the movement of charges during power generation. In the case of amorphous silicon, silicon-hydrogen bonds are separated by the movement of electric charges. Therefore, in order to use a non-single crystal solar cell advantageous in terms of cost for a long time, it is necessary to suppress the amount of carrier movement, that is, the output current I _out of the non-single crystal semiconductor solar cell as much as possible.

FIG. 7 is a graph showing power voltage characteristics of the solar cell. In the figure, the horizontal axis represents the output voltage V _out and the vertical axis represents the power P. The graph of FIG. 7 is based on the graph G1 of FIG. The electric power P has a maximum value P _max when the output voltage V _out = Vs. Therefore, when the output voltage _Vout is set to the reference point S (output voltage _Vout = Vs), power can be suppressed regardless of whether the output voltage _Vout is increased or decreased from Vs. Referring now to FIG. 6, when the output voltage _Vout is greater than Vs, the output current _Iout is smaller than Is. On the other hand, when the output voltage _Vout is made smaller than Vs, the output current _Iout becomes larger than Is. Therefore, when a non-single-crystal solar cell is used as the power source to be suppressed, either a method for suppressing the power by increasing the output voltage _{Vout above} Vs or a method for suppressing the power by decreasing the output voltage _Vout can be selected. However, the former is selected in consideration of durability. According to such a control method, since the amount of current flowing inside the non-single-crystal solar cell when power is suppressed can be suppressed, it is easy to realize a long life of the non-single-crystal solar cell. In the present embodiment, the input power of the output control circuit 330 is increased, that is, the ratio of the on-time of the transistor Tr is decreased, so that the supplied power is suppressed while the output current _Iout is suppressed.

(2) Wind Power Generation FIG. 8 is a graph showing current-voltage characteristics of wind power generation. In the figure, the horizontal axis represents the output voltage V _out and the vertical axis represents the output current I _out . Wind power generation shows a current-voltage characteristic that when the output voltage _Vout is increased, the output current _Iout increases and gradually decreases after reaching the maximum value. Even in wind power generation, the magnitude of power can be adjusted by adjusting the output current I _out and the output voltage V _out as control parameters. When the current-voltage characteristic of the wind power generator is represented by the graph G1, the power becomes maximum at the reference point S (output current I _out = Is, output voltage V _out = Vs) in FIG. When the wind force becomes stronger, the current-voltage characteristic becomes like the graph G3, and the power that can be output increases. On the other hand, when the wind power becomes weak, the current-voltage characteristic becomes as shown in the graph G2, and the power that can be output decreases. In any case, the power conversion device 312b having jurisdiction over the wind power generation 304 sets a control parameter at the reference point S that maximizes the power under the given wind conditions.

  In order to suppress the introduction cost of the multiple power supply control system 200, it may be possible to sacrifice the durability of the wind power generator to some extent. And in a wind power generator, the bearing part of a propeller usually tends to deteriorate over time. Therefore, in order to use a low-cost wind power generator for a long period of time, it is necessary to suppress the rotation speed of the wind power generator as much as possible.

  The electric power generated by the wind power generator is expressed as a product of the rotation speed and torque of the propeller. Since the rotational speed and the output voltage are directly proportional, the rotational speed of the air flow generator can be controlled by controlling the input impedance of the output control circuit 330.

The electric power P has a maximum value P _max when the output voltage V _out = Vs. Therefore, when the output voltage _Vout is set as a reference point (output voltage _Vout = Vs), power can be suppressed regardless of whether the output voltage _Vout is increased or decreased from Vs. When wind power generation is used as the power source to be suppressed, either the method of suppressing the power by increasing the output voltage _Vout beyond Vs or the method of suppressing the power by decreasing the output voltage can be selected. And select the latter. According to such a control method, since the rotation speed of the propeller of the wind power generator can be suppressed, it is easy to extend the life of the wind power generator. That is, the transistor Tr increases the on-time ratio, thereby reducing the rotation speed and suppressing the power supply.

  FIG. 9 is a flowchart of the process of suppressing the total power in the first embodiment. The process shown in the figure is repeatedly executed at regular time intervals. First, the measurement unit 110 measures the total power (S10). The condition determination unit 122 determines whether the output suppression condition is successful (S12). When the output suppression condition is satisfied (Y in S12), the power source selection unit 124 selects a suppression target power source (S14), and the instruction unit 132 instructs the power conversion device 312 having jurisdiction over the suppression target power source (S16). ). The output suppression condition is satisfied when the total power or the charging rate of the battery 404 exceeds a threshold value. The power conversion device 312 that has received the suppression instruction by the instruction receiving unit 322 changes the input impedance of the output control circuit 330, thereby suppressing the power supply of the suppression target power supply (S16). If the charging rate of the battery 404 is equal to or greater than a predetermined threshold and discharging is necessary (Y in S18), the charge / discharge control unit 136 discharges the battery 404 (S20). If no discharge is required (N in S18), S20 is skipped. When the output suppression condition is not satisfied (N in S12), the processes from S14 to S20 are skipped. In this case, if necessary, the control parameter of the power source to be suppressed may be returned to the reference point to cancel the power suppression.

  Each power conversion device 312 transmits operation information, and the monitoring unit 134 of the integrated control device 100 receives this (S22). The reliability update unit 126 updates the reliability information based on the newly received operation information (S24).

[Second Embodiment]
FIG. 10 is a block diagram illustrating a configuration of a multiple power supply control system according to the second embodiment. The multiple power supply control system 202 is also a system that realizes stable power supply from the entire system by controlling multiple power supplies. The configurations denoted by the same reference numerals as those in FIG. 1 have the same or similar functions as the configurations described in FIG. The multiple power supply control system 202 according to the second embodiment includes a power monitoring device 150 instead of including the integrated control device 100. The power monitoring device 150 corresponds to the measurement unit 110 of the integrated control device 100 and monitors the total power. Any one of the power conversion devices 412 may have the function of the power monitoring device 150. The function of the power conversion device 412 in the second embodiment is larger than that of the power conversion device 312 in the first embodiment, and details will be described later.

  Also in the second embodiment, as in FIG. 2, the measurement of the total power and the adjustment of the total power are repeatedly performed. However, it is the power monitoring device 150 that measures the total power, and is different in that each power conversion device 412 autonomously adjusts the total power.

  FIG. 11 is a functional block diagram of the power conversion device 412 according to the second embodiment. The power conversion device 412 includes an output control unit 420, a data processing unit 340, a reliability information holding unit 350, and an operation information holding unit 352. In addition to the function of the output control unit 320 of the power conversion device 312 in the first embodiment, the output control unit 420 should use the power supply 300 that it is responsible for (hereinafter referred to as “charged power supply”) as the suppression target power supply. It also has a function to determine. The data processing unit 340 executes various types of data processing based on data acquired from the output control unit 420, the reliability information holding unit 350, and the operation information holding unit 352. The data processing unit 340 also serves as an interface between the output control unit 420, the reliability information holding unit 350, and the operation information holding unit 352. The reliability information holding unit 350 holds reliability information in which the reliability of the assigned power source is registered. Moreover, the reliability information of the power supply 300 which the other power converter device 412 takes charge is also hold | maintained as needed. The operation information holding unit 352 holds operation information of the assigned power source.

  The data processing unit 340 includes a condition determination unit 342, a reliability update unit 344, a communication unit 348, and a monitoring unit 346. The condition determination unit 342 determines whether the output suppression condition is successful based on the measurement result of the total power by the power monitoring device 150. In addition, the success or failure of the output suppression condition may be determined by any one of the power conversion devices 412, and the other power conversion device 412 may receive the determination result. Alternatively, an output suppression instruction may be received from a dedicated device other than the power conversion device 412. The communication unit 348 transmits / receives reliability information to / from another power conversion device 412. As a result, the power conversion device 412 can acquire not only the reliability of the assigned power supply but also the reliability of the other power supply 300. The monitoring unit 346 acquires the operation information by monitoring the power supply in charge and registers it in the operation information holding unit 352. The reliability update unit 344 updates the reliability information based on the operation information.

  The power conversion device 412 may also transmit and receive various data such as reliability information by a dedicated communication line or a wireless system, or may be transmitted and received by superimposing the data on the power system such as the common power line 400 as an AC signal. .

  When the output suppression condition is satisfied, the output control unit 420 refers to the reliability information of each power source 300 and determines whether the assigned power source should be the suppression target power source. In the second embodiment, when the reliability of the assigned power source 300 is lower than any of the other power sources 300, the assigned power source is selected as the suppression target power source.

  FIG. 12 is a flowchart of a process for suppressing the total power in the second embodiment. The processing shown in the figure is also repeatedly executed at regular time intervals. First, the power converters 412 exchange reliability information with each other by the communication unit 348 (S30). Next, each power electronics device 412 acquires the measurement result of the total power from the power monitoring device 150 (S32), and the condition determination unit 342 determines whether the output suppression condition is successful (S34). When the output suppression condition is satisfied (Y in S34), the output control unit 420 determines whether the assigned power source should be the suppression target power source (S36). If the output suppression condition is not satisfied (N in S34), the processes in S36 and S38 are skipped. When selecting as the power source to be suppressed (Y in S36), the power supply is suppressed by controlling the input impedance of the output control circuit 330 (S38). When it is not selected as the power source to be suppressed (N of S36), the process of S38 is skipped. The monitoring unit 346 monitors the operation status and registers the operation information (S40). The reliability update unit 344 updates the reliability information based on the operation information (S42).

  Also in the second embodiment, when a lithium ion battery is used as the battery 404, even if any power conversion device 412 controls charging / discharging of the battery 404, the life of the battery 404 can be extended. Good.

  The multiple power supply control systems 200 and 202 have been described based on the first and second embodiments. According to the multiple power supply control systems 200 and 202, when the total power from each power supply 300 is periodically measured and it is desired to suppress the total power, the suppression target power supply can be selected in consideration of the service life of each power supply 300. Then, when there are a plurality of power suppression methods for the suppression target power source, the power suppression method with the lighter physical load on the suppression target power source is selected. It becomes easy. In addition, since the reliability information is updated according to the operation state, it is easy to align the end of use of the plurality of power supplies 300.

  Furthermore, since the total power is suppressed in consideration of the charging rate of the lithium ion battery, the life of the lithium ion battery is extended, and the stable operability of the plurality of power supply control systems 200 and 202 as a whole is improved.

In the second embodiment, the power conversion device 412 autonomously updates / exchanges reliability information. For this reason, the maintenance load due to the addition / deletion of the power supply 300 and the power conversion device 412 is reduced. For example, when a new power supply 300 is added, a power conversion device 412 that uses the power supply 300 as a responsible power supply may be added and the reliability may be initialized. After that, each power converter 412 automatically updates and exchanges reliability information. For this reason, the multiple power supply control system 202 excellent in expandability can be provided.
The integrated control device 100 and the power conversion device 412 may include a warning unit that transmits warning information when the reliability of any power source 300 becomes smaller than a predetermined threshold.

  In the present embodiment, the voltage suppression method for solar cells and wind power generation has been described. However, the control parameter is set at a reference point where the output can be increased or decreased by the control parameter, and the output is in the vicinity of the maximum value. The voltage suppression method according to the present invention can be applied to a “power supply that operates in a set state”. Each power supply 300 may be set in advance as to which of the areas where the control parameter value is increased from the reference point and the area where the value of the control parameter is decreased is an area having less influence on the durability. Then, the power converters 312 and 412 may determine how to change the control parameter when suppressing power from the maximum value according to this setting.

  In the present embodiment, the low reliability power source is selected as the suppression target power source, but as a modification, the suppression target power source may be selected based on elements other than the reliability level. For example, a power source that is easy to control power, that is, a power source with high controllability may be preferentially selected as the suppression target power source. The controllability is defined as a degree of control with a value that is normalized in a predetermined range, for example, 0 to 100, and the power source with the highest control degree / reliability ratio, that is, the power source with high control degree and low reliability is to be suppressed. You may select as a power supply. According to such a control method, it is possible to select a suppression target power source in consideration of not only reliability but also controllability.

  A power source that supplies a large amount of power due to external factors such as the weather may be preferentially selected as the power source to be suppressed. For example, when the wind power is equal to or greater than a predetermined value, the wind power generator may be selected as the suppression target power source in order to suppress the physical load of the wind power generator. In addition to this, the power of the power source having a large supply power may be suppressed when the total power is largely suppressed, and the power of the power source having a small supply power may be suppressed when the total power is to be suppressed a little.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .

DESCRIPTION OF SYMBOLS 100 Integrated control apparatus 110 Measurement part 120 Data processing part 122 Condition determination part 124 Power supply selection part 126 Reliability update part 130 Power supply control part 132 Instruction part 134 Monitoring part 136 Charge / discharge control part 140 Reliability information holding part 150 Power monitoring apparatus 200 Multiple power supply control system 202 Multiple power supply control system 300 Power supply 302 Solar cell 304 Wind power generation 306 Biomass 308 Fuel cell 310 Power supply group 312 Power converter 320 Output control unit 322 Instruction reception unit 324 Operation information transmission unit 330 Output control circuit 340 Data processing unit 342 Condition determination unit 344 Reliability update unit 346 Monitoring unit 348 Communication unit 350 Reliability information holding unit 400 Common power line 402 Inverter 404 Battery 412 Power converter 420 Output control unit

Claims (9)

A system that is connected to a plurality of irregular power sources, which are power sources that can control output increase / decrease according to control parameters, in which power that can be output varies depending on external factors,
An output control unit for controlling the output of each of the plurality of irregular power sources;
A measuring unit for obtaining a total amount of power output during a unit time from the plurality of irregular power sources,
A condition determination unit for determining whether or not the total electric energy satisfies a predetermined output suppression condition;
A power supply that is preferentially selected from among the irregular power supplies with low durability among the plurality of irregular power supplies with reference to reliability information indicating a high durability of the irregular power supply when the output suppression condition is satisfied A selection unit, and
The irregular power supply is operated in a state where control parameters are set so that the output is in the vicinity of the maximum value,
The output control unit includes a power suppression method having a lower influence on the durability of the selected irregular power source among a power suppression method by increasing a value of the control parameter and a power suppression method by decreasing the value. The multiple power supply control system characterized by suppressing the electric power output from the selected irregular power supply.   The multiple power supply control system according to claim 1, wherein the irregular power supply is a power supply derived from renewable energy.   The output control unit increases the output voltage of the solar cell and decreases the output current of the solar cell by increasing the output voltage of the solar cell when the selected irregular power source is a solar cell made of a non-single crystal semiconductor. The multiple power supply control system according to claim 1, wherein power output from a solar cell made of a crystalline semiconductor is suppressed.   When the selected irregular power source is a wind power generator, the output control unit decreases the output voltage of the wind power generator to reduce the rotation speed of the wind turbine in the wind power generator, thereby generating the wind power generation. The multiple power supply control system according to claim 1, wherein power output from the machine is suppressed. A monitoring unit for monitoring an operation state of the plurality of irregular power sources;
The multiple power supply control system according to any one of claims 1 to 4, further comprising a reliability update unit that updates the reliability information according to an operation state of each irregular power supply. A charge / discharge control unit for controlling charge / discharge of a lithium ion battery charged by electric power from the plurality of irregular power sources;
The condition determination unit determines that the output suppression condition is satisfied when a charging rate of the lithium ion battery exceeds a predetermined threshold,
The said charging / discharging control part discharges the said lithium ion battery, when the said total electric energy is suppressed triggered by establishment of the said output suppression conditions, The lithium ion battery is discharged as described in any one of Claim 1 to 5 characterized by the above-mentioned. Multiple power control system. Power that can be output due to external factors is changed, and is connected to one or more of a plurality of irregular power supplies that can be controlled to increase or decrease by control parameters. A plurality of power conversion devices that control the amount of power to be supplied to the common power line;
An integrated control device for controlling the plurality of power conversion devices,
The irregular power supply is operated with the control parameters set so that the output is in the vicinity of the maximum value,
The integrated controller is
A measurement unit for obtaining a total amount of power per unit time supplied to the common power line from the plurality of irregular power sources;
A condition determination unit that determines whether or not the total power satisfies a predetermined output suppression condition;
A power supply that is preferentially selected from among the irregular power supplies with low durability among the plurality of irregular power supplies with reference to reliability information indicating a high durability of the irregular power supply when the output suppression condition is satisfied A selection section;
A suppression instruction unit that transmits an output suppression instruction to a power conversion device in charge of controlling the selected irregular power source, and
The power converter is
An output control unit for controlling the output of the irregular power source of the connection destination;
A suppression instruction receiving unit that receives the suppression instruction from the integrated control device,
The output control unit, when receiving the suppression instruction, out of the power suppression method by increasing the value of the control parameter and the power suppression method by decreasing to the durability of the selected irregular power supply A multiple power supply control system, wherein the output of the selected irregular power supply is suppressed by a power suppression method having a lower influence. A device connected to an irregular power source, which is a power source capable of controlling the output increase / decrease by a control parameter, in which the power that can be output changes due to an external factor,
An output control unit for controlling the power to be provided to the common power line among the power output from the irregular power source;
A reliability information holding unit for holding reliability information indicating the durability of the irregular power supply;
A communication unit that transmits and receives reliability information with another power conversion device connected to another irregular power source,
The irregular power supply is a power supply that is operated in a state in which control parameters are set so that the output is in the vicinity of the maximum value,
The output control unit refers to the reliability information received from the other power converter when a predetermined output suppression condition is satisfied, and the durability of the irregular power source that the other power converter is in charge of If the irregular power supply that the device is in charge of is less durable, the irregularity in charge of the power suppression method by increasing the control parameter value and the power suppression method by decreasing the control parameter value A power conversion device that suppresses the output of the irregular power source in charge by a power suppression method having a lower influence on the durability of the power source. A monitoring unit that monitors the operational status of the irregular power supply at the connection destination;
The power conversion device according to claim 8, further comprising: a reliability update unit that updates the reliability information according to an operation state of the irregular power supply at the connection destination.

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