JP2012226501A - Control apparatus and supply power specification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus capable of specifying electric power which can be supplied by a solar battery in a self-sustained operation state and a supply power specification method.SOLUTION: PCS 200 has a storage part 240 for storing an operating point of a solar battery 11 and a control part 250 for controlling the operating point of the solar battery 11. The control part 250 specifies a characteristic curve corresponding to an environmental condition at a prescribed time point in a self-sustained operation state in which the solar battery 11 is paralleled off from a power system, based on the operation point of the solar battery 11 at the prescribed time point and the information stored in the storage part 240, and specifies a maximum supply power which the solar battery 11 can supply to a load 13 at the prescribed time point based on the specified characteristic curve.

Description

  The present invention relates to a control device provided in a power management system having a solar cell and a load, and a supply power specifying method applied to the power management system.

  Conventionally, in order to maximize the output (power generation capacity) of the solar cell, the operating point of the solar cell (a point determined by the operating point voltage value and the power value or a point determined by the operating point voltage value and the current value) is determined. Technology to change is known. Such a technique is called an MPPT (Maximum Power Point Tracking) method.

  Here, a technique has been proposed in which the operating point of the solar cell is quickly brought close to the optimal operating point by learning the optimal operating point (for example, Patent Document 1). Specifically, the solar cell is controlled by the following operation.

(1) Preliminarily measure the solar cell characteristic curve (eg, IV characteristics) using operating conditions such as solar radiation as parameters (2) Find the optimum operating point under the operating conditions (3) Current IV characteristics (4) The solar cell is controlled with the optimum operating point corresponding to the operating condition as the control target.

JP-A-7-234733

  By the way, in a state where the solar cell is connected to the power system, the solar cell may be simply controlled with the optimum operating point as a control target. On the other hand, in a state where the solar cell is disconnected from the power system (hereinafter referred to as a self-sustaining operation state), the operating point of the solar cell automatically changes according to the power consumption of the load connected to the solar cell. End up.

  As a result of intensive studies, the inventors have come up with a problem that it is unclear how much power can be supplied when the operating point of a solar cell automatically changes in a self-sustaining operation state. .

  Therefore, the present invention has been made to solve the above-described problems, and provides a control device and a supply power specifying method that can specify the power that can be supplied by a solar cell in a self-sustaining operation state. For the purpose.

  The control device according to the first feature is provided in a power management system having a solar cell and a load. The control device includes a storage unit that stores an operating point of the solar cell, and a control unit that controls the operating point of the solar cell. In the self-sustaining operation state in which the solar cell is disconnected from the power system, the control unit is configured based on the operating point of the solar cell at a predetermined time and the information stored in the storage unit to the environmental condition at the predetermined time. A corresponding characteristic curve is specified, and a maximum supply power that can be supplied to the load by the solar cell at the predetermined time point is specified based on the specified characteristic curve.

  In the first feature, the control device further includes an output unit that outputs the specified maximum supply power by display or outputs the specified maximum supply power by voice.

  In the first feature, the control device outputs a remaining power amount that can be supplied by the solar cell based on the specified maximum supply power, or displays the solar power based on the specified maximum supply power. It further includes an output unit that outputs the remaining power amount that can be supplied by the battery by voice.

  In the first feature, the control unit learns a characteristic curve corresponding to at least one environmental condition, and stores the learned characteristic curve in the storage unit.

  In the first feature, the characteristic curve is stored in the storage unit in advance.

  In the second feature, the supply power specifying method is applied to a power management system having a solar cell and a load. The supply power specifying method specifies a characteristic curve corresponding to an environmental condition at the predetermined time point based on an operating point of the solar cell at a predetermined time point in a self-sustaining operation state where the solar cell is disconnected from the power system. A and Step B that specifies the maximum supply power that the solar cell can supply to the load at the predetermined time point based on the characteristic curve specified in Step A.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus and supply electric power specific method which can specify the electric power which a solar cell can supply in a self-sustained operation state can be provided.

FIG. 1 is a diagram illustrating a configuration of a power management system 100 according to the first embodiment. FIG. 2 is a diagram illustrating a configuration of the customer 10 according to the first embodiment. FIG. 3 is a diagram illustrating a characteristic curve of the solar cell 11 according to the first embodiment. FIG. 4 is a diagram for explaining characteristic curve learning according to the first embodiment. FIG. 5 is a diagram illustrating the power strip 300 according to the first embodiment. FIG. 6 is a diagram illustrating a connection example of the load 13 according to the first embodiment. FIG. 7 is a flowchart showing the supply power specifying method according to the first embodiment.

  Hereinafter, a power management system according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of Embodiment]
The control apparatus which concerns on embodiment is provided in the power management system which has a solar cell and load. The control device includes a storage unit that stores an operating point of the solar cell, and a control unit that controls the operating point of the solar cell. In the self-sustaining operation state in which the solar cell is disconnected from the power system, the control unit is configured based on the operating point of the solar cell at a predetermined time and the information stored in the storage unit to the environmental condition at the predetermined time. A corresponding characteristic curve is specified, and a maximum supply power that can be supplied to the load by the solar cell at the predetermined time point is specified based on the specified characteristic curve.

  In the embodiment, the control unit specifies a characteristic curve corresponding to the environmental condition at a predetermined time, and specifies the maximum supply power based on the specified characteristic curve. In other words, the maximum supply power can be specified even when the operating point of the solar cell is automatically changed in the self-sustaining operation state. Thereby, it is possible to grasp how much power can be supplied in the self-sustaining operation state.

[First Embodiment]
(Power management system)
Hereinafter, the configuration of the power management system according to the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating a power management system 100 according to the first embodiment.

  As shown in FIG. 1, the power management system 100 includes a customer 10, an EMS 20, a substation 30, a smart server 40, and a power plant 50. The customer 10, the EMS 20, the substation 30 and the smart server 40 are connected by a network 60.

  The customer 10 has a distributed power source such as a solar battery. Moreover, the consumer 10 may have a storage battery etc. as a distributed power supply. The consumer 10 may be a single-family house, an apartment house such as a condominium, or a commercial facility such as a building.

  In the first embodiment, a customer group 10 </ b> A and a customer group 10 </ b> B are configured by a plurality of consumers 10. The consumer group 10A and the consumer group 10B are classified by, for example, a geographical area.

  The EMS 20 controls interconnection between the plurality of consumers 10 and the power system. The EMS 20 may be referred to as a CEMS (Cluster Energy Management System) in order to manage a plurality of consumers 10. Specifically, the EMS 20 disconnects between the plurality of consumers 10 and the power system at the time of a power failure or the like. On the other hand, the EMS 20 interconnects the plurality of consumers 10 and the power system when power is restored.

  In the first embodiment, an EMS 20A and an EMS 20B are provided. The EMS 20A controls, for example, interconnection between the customer 10 included in the customer group 10A and the power system. For example, the EMS 20B controls interconnection between the customer 10 included in the customer group 10B and the power system.

  The substation 30 supplies electric power to the plurality of consumers 10 via the distribution line 31. Specifically, the substation 30 steps down the voltage supplied from the power plant 50.

  In the first embodiment, a substation 30A and a substation 30B are provided. For example, the substation 30A supplies power to the consumers 10 included in the consumer group 10A via the distribution line 31A. For example, the substation 30B supplies power to the consumers 10 included in the consumer group 10B via the distribution line 31B.

  The smart server 40 manages a plurality of EMSs 20 (here, EMS 20A and EMS 20B). The smart server 40 also manages a plurality of substations 30 (here, the substation 30A and the substation 30B). In other words, the smart server 40 comprehensively manages the customers 10 included in the customer group 10A and the customer group 10B. For example, the smart server 40 has a function of balancing the power to be supplied to the consumer group 10A and the power to be supplied to the consumer group 10B.

  The power plant 50 generates power using thermal power, wind power, hydraulic power, nuclear power, and the like. The power plant 50 supplies power to the plurality of substations 30 (here, the substation 30A and the substation 30B) via the power transmission line 51.

(Customer)
Below, the structure of the consumer which concerns on 1st Embodiment is demonstrated, referring drawings. FIG. 2 is a diagram illustrating a configuration of the customer 10 according to the first embodiment. In FIG. 2, a PCS (Power Conditioning System) provided in the customer 10 will be mainly described.

  As shown in FIG. 2, the customer 10 has a solar cell 11. Moreover, the customer 10 has the switch 12 which switches the connection / disconnection between the solar cell 11 and an electric power system (distribution line 31). Further, the customer 10 has a PCS 200 that controls the solar cell 11.

  In addition, when the switch 12 is OFF, the state of the customer 10 is a state where the solar cell 11 is disconnected from the power system (distribution line 31) (hereinafter, a self-sustaining operation state). It should be noted that in the self-sustaining operation state, the operating point of the solar cell automatically changes according to the power consumption of the load 13 connected to the solar cell 11 (PCS 200). The load 13 is, for example, a refrigerator, lighting, an air conditioner, or the like.

  In addition, when the switch 12 is on, the state of the customer 10 is a state (connected state) in which the solar battery 11 is connected to the power system (distribution line 31). In the interconnected state, it is possible to sell the power generated by the solar cell 11.

  The PCS 200 includes a booster circuit 210, an inverter circuit 220, a detection circuit 230, a storage unit 240, a control unit 250, and an output unit 260.

  The booster circuit 210 is connected to the solar cell 11 and the inverter circuit 220. The booster circuit 210 boosts the voltage of power output from the solar cell 11.

  The inverter circuit 220 is connected to the booster circuit 210 and is connected to the power system (distribution line 31) via the switch 12. The inverter circuit 220 converts AC power supplied from the power system (distribution line 31) into DC power. Inverter circuit 220 converts the DC power supplied from booster circuit 210 into AC power.

  The detection circuit 230 detects the value of power output from the solar cell 11. Specifically, the detection circuit 230 detects the voltage value (V) and current value (I) of the power output from the solar cell 11.

  The storage unit 240 stores various information. For example, the storage unit 240 stores a characteristic curve indicating the transition of the operating point of the solar cell 11. The characteristic curve is a characteristic indicating the transition of the operating point of the solar cell 11. For example, the characteristic curve is an IV characteristic (curve) indicating the relationship between the output current value (I) of the solar cell 11 and the output voltage value (V) of the solar cell 11. Or the output characteristic (curve) which shows the relationship between the output electric power value (W) of the solar cell 11 and the output voltage value (V) of the solar cell 11 may be sufficient.

  In the first embodiment, a case where the characteristic curve is an output characteristic (curve) is illustrated. For example, the characteristic curve is expressed by a curve indicating the transition of the operating power point of the solar cell 11 as shown in FIG. Since the characteristic curves differ depending on the environmental conditions in which the solar cell 11 operates, six types of curves (curves C1 to C6) are shown in FIG.

  In addition, environmental conditions are information, such as solar radiation amount and the panel temperature of the solar cell 11, for example. Here, the solar radiation amount will be described as an example of the environmental condition.

  As shown in FIG. 3, when the amount of solar radiation is the largest, the characteristic curve is the curve C1. When the amount of solar radiation is the smallest, the characteristic curve is the curve C6. Thus, the greater the amount of solar radiation, the greater the output power value (W) of the solar cell 11.

  In addition, it is possible to estimate another curve using the curve matched with the known solar radiation amount among the curves C1-C6. Therefore, the curve stored in the storage unit 240 may be any one of the curves C1 to C6. In addition, when one curve is memorize | stored in the memory | storage part 240, it is preferable that the curve C1 when the amount of solar radiation is the largest is memorize | stored in the memory | storage part 240. FIG.

  Here, the characteristic curve may be stored in the storage unit 240 in advance. It should be noted that in such a case, the characteristic curve differs depending on the structure of the solar cell 11 (for example, a crystal system or a thin film system). Alternatively, it should be noted that the characteristic curve varies depending on the manufacturer of the solar cell 11.

  The characteristic curve may be stored in the storage unit 240 by learning after the solar cell 11 is installed. Details of the learning method will be described later (see FIG. 4).

  The control unit 250 is connected to the booster circuit 210 and the detection circuit 230. The control unit 250 controls the operating point of the solar cell 11 by the pulse control of the booster circuit 210. Here, in the interconnected state, control unit 250 controls the operating point of solar cell 11 according to the MPPT (Maximum Power Point Tracking) method.

  Specifically, the control unit 250 determines the predetermined time point based on the operating point of the solar cell 11 at a predetermined time point and the information stored in the storage unit 240 in the self-sustaining operation state where the solar cell 11 is disconnected from the power system. The characteristic curve corresponding to the environmental conditions in is specified. Subsequently, the control unit 250 specifies the maximum supply power that the solar cell 11 can supply to the load 13 at a predetermined time based on the specified characteristic curve.

For example, a method for specifying the maximum power supply in the self-sustaining operation state will be described with reference to FIG. Here, a case where the operating point of the solar cell 11 is P ₁ at a predetermined time point will be described. That is, the output power value of the solar cell 11 is W1, and the output voltage value of the solar cell 11 is V1. Of course, the operating point of the solar cell 11 can be detected by the detection circuit 230 described above.

  It should be noted that in the self-sustaining operation state, the output power value of the solar cell 11 automatically changes according to the power consumption of the load 13.

In such cases, the first, control unit 250, based on the curve C1~ curve C6, identifies the curve passing through the operating point _{P 1.} Here, the curve passing through the operating point P ₁ is illustrated a case a curve C3. However, even in the absence of a curve passing through the operating point P _1, on the basis of a curve through the points near the operating point P _1, curve passing through the operating point P ₁ may be identified.

Secondly, the control unit 250 specifies the optimum operating point P _MAX of the solar cell 11 on the specified curve (here, the curve C3). The controller 250 identifies a power W3 corresponding to the optimum operating point _{P MAX} as the maximum supply power.

  Note that, in the interconnection state in which the solar cell 11 is linked to the power system, the operating point of the solar cell 11 is brought close to the optimum operating point. Therefore, it should be noted that in the interconnected state, when the output power value of the solar cell 11 is W1, the output voltage value of the solar cell 11 is V2.

  Hereinafter, learning of the characteristic curve will be described with reference to FIG. The control unit 250 learns a characteristic curve corresponding to at least one environmental condition, and stores the learned characteristic curve in the storage unit 240.

  Specifically, first, the control unit 250 plots the operating point of the solar cell 11 in a predetermined period (for example, one month) as shown in FIG. It should be noted that since the operating point is plotted in the interconnected state, the operating point of the solar cell 11 is substantially equal to the optimal operating point. It should be noted that the operating point of the solar cell 11 is detected by the detection circuit 230 described above.

  Second, the control unit 250 estimates the optimum operating point for each environmental condition (for example, solar radiation amount) based on the operating point plot result, and based on the optimum operating point, the short circuit current value, and the open circuit voltage value. Learn characteristic curves. It should be noted that the short circuit current value and the open circuit voltage value are known.

Note that the controller 250 estimates only the optimum operating point P _PEAK having the largest output power value of the solar cell 11 and learns a characteristic curve based on the optimum operating point P _PEAK , the short-circuit current value, and the open-circuit voltage value. In such a case, it is not necessary to estimate the optimum operating point for each environmental condition (for example, solar radiation amount).

  Returning to FIG. 2, the output unit 260 is, for example, a display or a speaker. The output unit 260 may output the specified maximum supply power by display. Alternatively, the output unit 260 outputs the specified maximum supply power by voice. Alternatively, the output unit 260 may output the remaining power amount that can be supplied by the solar cell 11 (that is, the power consumption amount of the load 13 that can be added) by display based on the specified maximum supply power. The output unit 260 may output the remaining power amount that can be supplied by the solar cell 11 (that is, the power consumption amount of the load 13 that can be added) by voice based on the specified maximum supply power.

  For example, a configuration example of the output unit 260 will be described with reference to FIG. FIG. 5 is a diagram showing a power strip 300 that is plugged into a stand-alone operation outlet provided in the PCS 200. The power strip 300 has a plurality of outlets (outlet 311 to outlet 313). The numbers assigned to the outlets (here, “1”, “2”, and “3”) indicate the priority order of the outlets.

  The output unit 260 is provided in the power strip 300. Here, a case where the output unit 260 is a level meter is illustrated. For example, the output unit 260 displays the used power in a predetermined color (for example, “red”) and displays the remaining power amount in a predetermined color (for example, “green”).

  In addition, when the electric energy supplied by the solar cell 11 falls, you may cut | disconnect electric power in an order from the outlet socket to which the lower number was allocated. Alternatively, a relay or a semiconductor switch for cutting off the electric power may be incorporated, and a large-capacity capacitor may be incorporated in each outlet.

  By using such a power strip 300, for example, as shown in FIG. 6, power is supplied to each outlet following the maximum supplyable amount. The load A is a load connected to the outlet 311 assigned the priority “1”, and the load B is a load connected to the outlet 312 assigned the priority “2”. Is a load connected to the outlet 313 to which the priority “3” is assigned.

(Supply power identification method)
Hereinafter, a method for specifying supply power according to the first embodiment will be described with reference to the drawings. FIG. 7 is a flowchart showing the supply power specifying method according to the first embodiment.

  As shown in FIG. 7, in step 10, the control unit 250 has the operating point of the solar cell 11 at a predetermined time and the information stored in the storage unit 240 in the self-sustaining operation state where the solar cell 11 is disconnected from the power system. Based on the above, a characteristic curve corresponding to the environmental condition at a predetermined time is specified.

  In step 20, the control unit 250 specifies the maximum supply power that the solar cell 11 can supply to the load 13 at a predetermined time based on the specified characteristic curve.

(Function and effect)
In the first embodiment, the control unit 250 specifies a characteristic curve corresponding to the environmental condition at a predetermined time, and specifies the maximum supply power based on the specified characteristic curve. In other words, even if the operating point of the solar cell 11 is automatically changed in the self-sustaining operation state, the maximum supply power can be specified. Thereby, it is possible to grasp how much power can be supplied in the self-sustaining operation state.

  In the first embodiment, the output unit 260 outputs the maximum supply power or the remaining power amount. Therefore, it is possible to easily grasp how much power can be supplied in the self-sustaining operation state. Further, when the amount of power supplied from the power tap 300 decreases, the PCS 200 can be driven without stopping by cutting off the power in order from the outlet with the lowest priority. If such a shut-off is not performed, in order to prevent hunting operation, it is generally necessary to stop the PCS 200 temporarily and perform a manual return operation even if the amount of solar radiation is improved and power can be secured again. It is possible to avoid stopping the PCS 200 itself by adjusting the automatic shutoff / return of the form.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment, the case where the environmental condition is the amount of solar radiation has been mainly described. However, the environmental condition may be the panel temperature, temperature, humidity, etc. of the solar cell 11. For example, when a temperature sensor that detects the panel temperature of the solar cell 11 is provided, the control unit 250 may correct the characteristic curve based on the panel temperature. Similarly, when a weather sensor that detects temperature, humidity, and the like is provided, the control unit 250 may correct the characteristic curve based on the temperature, humidity, and the like.

  DESCRIPTION OF SYMBOLS 10 ... Consumer, 11 ... Solar cell, 12 ... Switch, 13 ... Load, 20 ... EMS, 30 ... Substation, 31 ... Distribution line, 40 ... Smart server, 50 ... Power plant, 51 ... Transmission line, 60 ... Network , 100 ... Power management system, 200 ... PCS, 210 ... Boost circuit, 220 ... Inverter circuit, 230 ... Detection circuit, 240 ... Storage unit, 250 ... Control unit, 260 ... Output unit, 300 ... Power tap, 311 to 313 ... Outlet

Claims (6)

A control device provided in a power management system having a solar cell and a load,
A storage unit for storing an operating point of the solar cell;
A control unit for controlling the operating point of the solar cell,
In the self-sustaining operation state in which the solar cell is disconnected from the power system, the control unit is configured based on the operating point of the solar cell at a predetermined time and the information stored in the storage unit to the environmental condition at the predetermined time. Identify the corresponding characteristic curve,
A control device that identifies a maximum supply power that the solar cell can supply to the load at the predetermined time point based on the identified characteristic curve.   The control device according to claim 1, further comprising: an output unit that outputs the specified maximum supply power by display or outputs the specified maximum supply power by voice.   Based on the specified maximum supply power, the remaining power amount that can be supplied by the solar cell is output by display, or the remaining power amount that can be supplied by the solar cell is voiced based on the specified maximum supply power. The control device according to claim 1, further comprising an output unit that outputs the output of the control unit.   The control device according to claim 1, wherein the control unit learns a characteristic curve corresponding to at least one environmental condition, and stores the learned characteristic curve in the storage unit.   The control device according to claim 1, wherein the characteristic curve is stored in the storage unit in advance. A method for specifying supply power applied to a power management system having a solar cell and a load,
In a self-sustaining operation state where the solar cell is disconnected from the power system, a step A for identifying a characteristic curve corresponding to the environmental condition at the predetermined time point based on the operating point of the solar cell at the predetermined time point;
A method of specifying supply power, comprising: specifying a maximum supply power that the solar cell can supply to the load at the predetermined time point based on the characteristic curve specified in step A.

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