Power management device

Abstract

To provide a power management device capable of suppressing occurrence of a problem due to a change in solar radiation in a charging system that does not include a power storage facility.SOLUTION: In a charging system B1 including a plurality of power facilities 5 including a solar power generation facility 2 and an EV stand 4, and a load L, a power management apparatus A1 controls a connection point power P(t), which is an input / output power of an entire charging system B1, to a target power Pc. Each power facility 5 includes power control devices 22 and 42 that control an individual power that is an input / output power of each facility. The power management apparatus A1 includes: a predicting device 12 that predicts a future power generateable power of the photovoltaic power generation facility 2 for a predetermined time T1 and outputs the predicted power generateable power as a power generateable prediction P2; and a command device 13 that outputs a command to each power control device to control the corresponding individual power. The command device 13 changes a target for the control based on a comparison between the power generateable prediction P2 input from the prediction device 12 and a power demand including a power consumption PL of the load L.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power management device for controlling a charging system. [Background technology]

[0002] In recent years, power systems have become widespread, which include multiple pieces of power equipment connected to a power grid, manage these pieces of power equipment using a power management device, and control the power transmitted to and received from the power grid. Furthermore, power systems that perform control based on predicted values ​​of future solar radiation have been developed. For example, Patent Document 1 discloses a power system that outputs a countermeasure command to each power control device to perform control when a time-series change in predicted values ​​of future solar radiation satisfies a predetermined condition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7259183 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes control when a sudden drop in the output power of a solar power generation facility is predicted and when the output power of a solar power generation facility is predicted to become unstable, but does not describe control when an increase in the output power of a solar power generation facility is predicted. For example, if the power system is a charging system without a power storage facility, when the output power of the solar power generation facility increases, the received power of the power system may decrease so much that a momentary reverse power flow occurs. Patent Document 1 also does not describe control when performing stand-alone operation in the event of a grid fault. Even during stand-alone operation, it is desirable to balance power supply and demand and ensure a stable power supply to electric vehicles without shutting down the solar power generation facility.

[0005] The present invention was devised in light of the above-mentioned circumstances, and aims to provide a power management device that can prevent problems caused by changes in solar radiation in a charging system that does not have a storage facility. [Means for solving the problem]

[0006] The power management device provided by the present invention is a power management device that controls the connection point power, which is the input and output power of the entire charging system, to a target power in a charging system that includes a photovoltaic power generation facility that generates electricity using solar cells and a plurality of power facilities including an EV stand that supplies power to electric vehicles, and a load, wherein each of the power facilities is equipped with a power control device that controls the individual power, which is the input and output power, and the device is equipped with a prediction device that predicts the future power generateable power of the photovoltaic power generation facility for a predetermined time period and outputs it as a power generation capacity prediction, and a command device that outputs commands to each of the power control devices to control the corresponding individual power, and the command device changes the target for control based on a comparison of the power generation capacity prediction input from the prediction device with the demand power including the power consumption of the load.

[0007] In a preferred embodiment of the present invention, the command device increases the target power when the predicted power generation capacity changes from below a threshold based on the power demand to equal to or above the threshold.

[0008] In a preferred embodiment of the present invention, the command device continues the increased state in which the target power has been increased for a duration, the duration being at least twice the predetermined time.

[0009] In a preferred embodiment of the present invention, if the power generation forecast again changes from below the threshold to above the threshold while the increasing state is continuing, the command device continues the increasing state for the duration from that point onwards.

[0010] In a preferred embodiment of the present invention, when the charging system is disconnected from the power grid, if the surplus power calculated based on the power generation forecast and the power demand is greater than a first power, the command device increases the target value of the charging power to the electric vehicle in the power control device of the EV stand, and if the surplus power is less than a second power, decreases the target value of the charging power to the electric vehicle in the power control device of the EV stand.

[0011] In a preferred embodiment of the present invention, the command device calculates an index based on the connection point power and the target power and outputs the index as the command, and each of the plurality of power control devices includes a target power calculation unit that calculates an individual power target, which is a target value for the individual power to be controlled, based on the index input from the command device and a predetermined optimization problem, and a control unit that controls the individual power based on the individual power target. [Effects of the Invention]

[0012] According to the present invention, the command device changes the control target based on a comparison between the power generation capacity forecast input from the forecast device and the power demand including the power consumption of the load. As a result, the power management device according to the present invention can prevent problems caused by changes in solar radiation in a charging system that does not include a power storage facility. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing the overall configuration of a charging system including a power management device according to a first embodiment. [Figure 2] 10 is an example of a flowchart for explaining a first control process. [Figure 3] 10 is a time chart showing changes in each value when a simulation of the first control process is performed. [Figure 4] FIG. 4 is an enlarged view of a portion of the time chart shown in FIG. 3. [Figure 5]FIG. 4 is an enlarged view of a portion of the time chart shown in FIG. 3. [Figure 6] 10 is a time chart showing changes in each value when another simulation of the first control process is performed. [Figure 7] 10 is an example of a flowchart for explaining a second control process. [Figure 8] 10 is a time chart showing changes in each value when a simulation of the second control process is performed. [Figure 9] FIG. 10 is a block diagram showing the overall configuration of a charging system including a power management device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0015] FIG. 1 is a block diagram showing the overall configuration of a charging system B1 including a power management device A1 according to a first embodiment. The charging system B1 is connected to a power grid C and can transmit and receive power to and from the power grid C. The charging system B1 is controlled so that the power at the connection point between the charging system B1 and the power grid C (hereinafter referred to as "connection point power") becomes a target power. In the following description, when the charging system B1 receives power from the power grid C, the connection point power is taken as a positive value. On the other hand, when the charging system B1 transmits power to the power grid C (reverse power flow), the connection point power is taken as a negative value. The charging system B1 does not allow reverse power flow, and is operated so that the connection point power does not become a negative value. The charging system B1 includes a power management device A1, a solar power generation facility 2, and multiple EV stands 4. Note that multiple solar power generation facilities 2 may be provided. The EV stand 4 may be one. When the solar power generation facility 2 and the multiple EV stands 4, which are managed by the power management device A1, are collectively referred to as "power facility 5."

[0016] The power management device A1 monitors the node power P(t) and sets the node power P(t) to the target power P cThe target power P c is set by an operator according to a target demand, or is set by a higher-level management device (such as a management device of a power company) through communication. Furthermore, power management device A1 predicts changes in solar radiation and takes measures in advance based on the predicted value of the power that can be generated by photovoltaic power generation facility 2. Power management device A1 includes multiple cameras 11, a prediction device 12, and a command device 13.

[0017] The camera 11 is a hemispherical camera, e.g., an imaging device with an ultra-wide-angle fisheye lens. The camera 11 is fixedly installed with the lens facing vertically upward. As shown in FIG. 1 , the camera 11 captures images with a horizontal azimuth angle α ranging from 0° to 360° and an elevation angle β ranging from 0° to 90°, with the origin O at the installation position as the center. Note that the minimum elevation angle β of the camera 11 may be slightly less than or equal to 0°. The camera 11 outputs image data of the captured hemispherical image to the prediction device 12. In this specification, the terms "spherical camera" and "spherical image" are used to refer to a "spherical camera" that captures the entire range of an elevation angle β ranging from -90° to 90° and a "spherical image" that captures the captured image, as opposed to a "spherical camera" and a "spherical image" that capture half of that range. Note that they may also be called "omnidirectional camera" and "omnidirectional image." The sun is always visible in a hemispherical image from sunrise to sunset unless it is obscured by surrounding buildings or the like. Therefore, camera 11 can capture an image including the sun while remaining fixed. Therefore, a mechanism for tracking the sun and changing the capturing direction is not required. Camera 11 may also be a spherical camera.

[0018] In this embodiment, the power management device A1 includes multiple cameras 11. At least one camera 11 is installed near a solar cell 21 of the solar power generation facility 2. The camera 11 can capture an image of the sky centered on the sky above the solar cell 21. The hemispherical image captured by the camera 11 also captures the panels of the solar cell 21.

[0019] At least one other camera 11 is installed at a position slightly away from the solar cell 21. This camera 11 can capture an image of the sky centered above the installation location. Therefore, even if a camera 11 installed near the solar cell 21 cannot capture a portion of the sky due to a nearby building or the like, this camera 11 can capture that portion (it is installed at such a position). Furthermore, because the lens of the camera 11 is an ultra-wide-angle fisheye lens, the image becomes more curved the further away from the center. By acquiring hemispherical images from multiple cameras 11 installed at positions distant from each other, the prediction device 12 of the power management device A1 can complement each other's images and perform more accurate predictions. Note that the number of cameras 11 included in the power management device A1 is not limited. For example, the power management device A1 may be equipped with only one camera 11 when there are no buildings or other obstructions to the sky around the solar cell 21.

[0020] The prediction device 12 predicts future solar radiation based on image data of the hemispherical image input from the camera 11, and predicts the power generation capacity of the solar power generation facility 2. The prediction device 12 extracts clouds from multiple hemispherical images acquired in time series, recognizes their shapes, and detects the movement speed of the clouds. The prediction device 12 estimates the future position of each cloud and calculates a solar forecast index, which is the percentage of the sun that will be hidden by the clouds. The prediction device 12 predicts the future power generation capacity based on the solar forecast index, other observation information, and information about the solar power generation facility 2. In this embodiment, the prediction device 12 predicts the power generation capacity a predetermined time T1 (e.g., one minute) from now. Note that there are no limitations on how far into the future the prediction device 12 predicts, and the predetermined time T1 is not limited. However, prediction accuracy decreases if the prediction is made too far in the future, and countermeasures will not be able to be taken in time if the prediction is made too close, so a time of about one minute is preferable. The prediction device 12 outputs the predicted future power generation capacity to the command device 13 at predetermined intervals (e.g., five seconds). The interval at which the prediction device 12 outputs (predicts) the future generateable power is not limited.

[0021] The method of predicting solar radiation by the prediction device 12 is not limited. For example, the prediction device 12 may estimate the type, thickness, height, etc. of clouds from a hemispherical image and use the information to calculate the solar prediction index. The prediction device 12 may also predict solar radiation using other methods. In this case, the power management device A1 does not need to be equipped with multiple cameras 11, and may be equipped with other equipment. The prediction device 12 may also predict the power that can be generated by the solar power generation facility 2 using a method other than predicting solar radiation. However, the prediction device 12 needs to have a certain degree of high prediction accuracy.

[0022] The command device 13 uses the power value detected at the connection point between the charging system B1 and the power system C as the connection point power P(t). Note that the command device 13 may receive individual powers, which are individual input / output powers detected at each power facility 5 and the load L, and use an estimated value calculated from these individual powers as the connection point power P(t). The command device 13 may receive the set target power P c and the connection point power P(t). Specifically, the command device 13 controls the power equipment 5 based on the difference between the target power P c and the connection point power P(t), an individual power target, which is a target value for each individual power, is output as a command to each power facility 5. Even for the same type of power facility 5, the command device 13 outputs different individual power targets depending on the status of each power facility 5. For example, if there are multiple EV stands 4, the command device 13 outputs different individual power targets depending on the storage capacity and remaining capacity of each. Each power facility 5 controls its own individual power to the input individual power target. For example, if the connection point power P(t) is equal to the target power P c If the target power P is larger than the target power P, the command device 13 commands the photovoltaic power generation equipment 2 to increase the output and commands the EV stand 4 to discharge. c and the connection point power P(t), the state of each piece of power equipment 5, etc. The command device 13 issues commands to each piece of power equipment 5 in accordance with a preset algorithm. Note that the communication method between the command device 13 and each piece of power equipment 5 is not limited, and may be wired communication or wireless communication.

[0023] Furthermore, the command device 13 receives, at predetermined intervals, predicted future power generation capacity (hereinafter referred to as "power generation capacity prediction") from the prediction device 12. The command device 13 performs a first control process or a second control process according to the input power generation capacity prediction. The first control process and the second control process will be described in detail later.

[0024] In this embodiment, the prediction device 12 and the command device 13 are separate devices, and the prediction device 12 and the command device 13 are capable of communicating with each other. The prediction device 12 and the command device 13 may communicate with each other via wired or wireless communication. The command device 13 has the functions of a power management device of a general power system, plus a function of performing a first control process and a second control process according to the prediction result of the prediction device 12. The command device 13 may be configured by adding programs for the first control process and the second control process to a conventional power management device. The prediction device 12 and the command device 13 may not be separate devices, but may be a single device. In other words, the power management device A1 may be a single computer device equipped with a CPU and memory, and the prediction device 12 and the command device 13 may be included as functional components of the computer device.

[0025] The solar power generation facility 2 is a facility that generates solar power. The solar power generation facility 2 includes a solar cell 21 and a power conditioner 22. The solar cell 21 receives sunlight and generates power. There are no limitations on the type or connection shape of the solar cell 21. The solar cell 21 outputs the generated DC power to the power conditioner 22. The power conditioner 22 converts the DC power input from the solar cell 21 into AC power and outputs it. The power conditioner 22 controls the output power (individual power) so that it becomes an individual power target, which is a command input from the command device 13. The output power (individual power) of the solar power generation facility 2 is a positive value when it is output.

[0026] The EV stand 4 is a facility that supplies power to an electric vehicle 41. The electric vehicle 41 is a vehicle that is equipped with a storage battery, is powered by electricity, and can charge the storage battery externally, and includes, for example, plug-in hybrid vehicles. Fuel cell vehicles are also included in the electric vehicle 41 because they are equipped with a storage battery that stores generated electricity and are powered by electricity. The EV stand 4 is also used to adjust the power supply in the charging system B1. In other words, the EV stand 4 has the same function as a power storage facility. The EV stand 4 is equipped with a charger / discharger 42 and an electric vehicle 41 connected to the charger / discharger 42. The charger / discharger 42 charges the storage battery of the electric vehicle 41 by converting AC power to DC power and outputting it to the storage battery of the electric vehicle 41. The charger / discharger 42 also converts DC power input from the storage battery of the electric vehicle 41 into AC power and outputs it, thereby discharging the storage battery of the electric vehicle 41. Furthermore, charger / discharger 42 controls the input / output power (individual power) so that it becomes the individual power target, which is a command input from command device 13. The input / output power (individual power) of EV stand 4 is a positive value when the storage battery of electric vehicle 41 is discharging (output), and a negative value when the storage battery of electric vehicle 41 is charging (input). Therefore, charger / discharger 42 discharges the storage battery of electric vehicle 41 when a positive individual power target value is input from command device 13, and charges the storage battery of electric vehicle 41 when a negative individual power target value is input from command device 13.

[0027] Next, a first control process and a second control process performed by the command device 13 will be described. c and the node power P(t), the first control process or the second control process is performed in accordance with the power generation possibility prediction input from the prediction device 12.

[0028] While the available power generation of the solar power generation facility 2 is small, the connection point power P(t) is equal to the target power P c Therefore, the command device 13 commands the photovoltaic power generation facility 2 to maximize its output, so that the output power of the photovoltaic power generation facility 2 becomes approximately equal to the power that can be generated. Lto target power P c If the power value exceeds the power value obtained by subtracting , the node power P(t) will suddenly drop. In this case, the node power P(t) will be controlled to the target power P c However, there is a possibility that reverse power flow may occur momentarily during a sudden drop. Since the charging system B1 does not allow reverse power flow, measures to prevent reverse power flow from occurring are necessary. In addition, if the output power of the photovoltaic power generation facility 2 is L The target power P is calculated from the total power of Pch_max and the maximum charging power Pch_max. c The same problem occurs when the maximum charging power Pch_max exceeds the power value obtained by subtracting the maximum charging power Pch_max. The maximum charging power Pch_max is the absolute value of the lower limit of the total power of the input / output power (individual power) of multiple EV stands 4. The first control process is a process for preventing the occurrence of reverse power flow when the output power (potential power generation) of the photovoltaic power generation facility 2 increases.

[0029] The command device 13 performs a first control process in accordance with the power generation possibility prediction input from the prediction device 12. The power generation possibility prediction is a prediction of the power generation possibility after a predetermined time T1 (for example, one minute). The command device 13 performs a first control process in accordance with the power generation possibility prediction input from the prediction device 12. L From target standard P c The first threshold P minus 0 S1 (=P L -P c 0) to the first threshold P S1 When the available power generation exceeds the first threshold P S1 Less than the first threshold P S1 When the power at the connection point P(t) is predicted to be greater than or equal to the target power P c Increase the target standard P c 0 is the target power P c The reference value is the set value before the increase (for example, 10 kW). c 1 is not limited to, but is, for example, 20 kW. c The target power P is set appropriately according to the results of simulations and experiments. c is increased, the node power P(t) becomes the target power P cTherefore, the command device 13 performs normal control by issuing a command to the EV stand 4 to increase the charging power and issuing a command to the solar power generation facility 2 to reduce the output. As a result, the connection point power P(t) becomes smaller than the target power P c After a predetermined time T1, the actual power that can be generated increases in accordance with the first threshold value P S1 Less than the first threshold P S1 When the target power P(t) is reached, the node power P(t) is increasing, so even if the node power P(t) suddenly drops due to a sudden rise in the output power (potential power), the occurrence of reverse power flow is prevented. c The duration T2 for maintaining the increased state of the increased value must be at least longer than the predetermined time T1 (for example, 1 minute), and is preferably at least twice the predetermined time T1. Note that the duration T2 is not limited.

[0030] The power generation forecast is based on the first threshold P S1 It rises sharply from below to the first threshold P S1 After reaching the first threshold P S1 Return to below the first threshold P S1 In this case, the power generation forecast may be greater than or equal to the first threshold P S1 After the duration T2 has elapsed since the target power P c Immediately after returning to its original state from the increasing state, the available power generation suddenly rises again and exceeds the first threshold P S1 If the target power P(t) is exceeded, the restored node power P(t) may suddenly drop, potentially causing a reverse power flow. To prevent this, one method is to set the duration T2 to a sufficiently large value (for example, about 5 minutes). However, this method may result in the increased state of the node power P(t) being extended unnecessarily. Another method is to set the duration T2 to, for example, about 2 minutes, and c While the increase in power generation capacity continues, the power generation forecast again exceeds the first threshold P S1 Less than the first threshold P S1 If the target power P c This method can prevent the state in which the node power P(t) is increased from becoming unnecessarily long.

[0031] In addition, the command device 13 determines whether the power generation possibility prediction is L The target reference power P is calculated from the total power of the c Second threshold P minus 0 S2 (=P L +Pch_max-P c 0) to the second threshold P S2 When the available power generation exceeds the second threshold P S2 Less than the second threshold P S2 When the power at the connection point P(t) is predicted to be greater than or equal to the target power P c The increase amount ΔP c 2 is, but is not limited to, 40 kW, for example. c 2 is set appropriately according to the results of simulations and experiments. c is increased, the node power P(t) becomes the target power P c Since the output of the solar power generation facility 2 is smaller than the target power P, the command device 13 issues a command to the solar power generation facility 2 to suppress its output as normal control. Note that the EV stands 4 are each charging at their maximum capacity, so the charge amount cannot be increased. By suppressing the output of the solar power generation facility 2, the connection point power P(t) becomes smaller than the target power P. c After a predetermined time T1, the actual power that can be generated increases in accordance with the second threshold P S2 Less than the second threshold P S2 When the power output becomes equal to or greater than the first threshold P(t), the node power P(t) is increasing, so that even if the node power P(t) suddenly drops due to a sudden increase in the output power (potential power generation), the occurrence of reverse power flow is prevented. S1 Less than the first threshold P S1 The method for preventing the occurrence of reverse power flow due to a re-increase in the power generation forecast is the same as when the power generation forecast exceeds the first threshold P S1 Less than the first threshold P S1 This is the same as when the above occurs.

[0032] 2 is an example of a flowchart for explaining the first control process performed by the command device 13. The first control process is executed at predetermined intervals (for example, at each time when a power generation availability prediction is input from the prediction device 12).

[0033] First, the power generation prediction P2 input from the prediction device 12 is acquired (S1). Next, the power generation prediction P2 is compared with the second threshold P S2 Less than the second threshold P S2 In other words, it is determined whether the previous power generation possibility prediction P2 is equal to or greater than the second threshold value P S2 If the predicted power generation capacity P2 is less than the second threshold P S2 It is determined whether the second threshold value P S2 is the load power consumption P L The target reference power P is calculated from the total power of the c It is calculated each time by subtracting 0.

[0034] The predicted power generation potential P2 is the second threshold P S2 Less than the second threshold P S2 If it is equal to or greater than the target power P (S2: YES), it is determined whether this determination result (S2: YES) is the first time (S3). c is the target standard P c It is determined that the target power P c is the target standard P c Increase from 0 ΔP c 2 (S4), and the target power P c On the other hand, if it is not the first time (S3: NO), the time count from the start of the increasing state is reset to "0" (S5), and the first control process ends.

[0035] If the answer is "NO" in step S2, the predicted power generation capacity P2 is equal to or greater than the first threshold P S1 Less than the first threshold P S1 It is determined whether the predicted power generation capacity P2 is equal to or greater than the first threshold value P S1 Less than the first threshold P S1If it is equal to or greater than the target power P (S6: YES), it is determined whether or not this determination result (S6: YES) is the first time (S7). c is the target standard P c Increase from 0 ΔP c The count is incremented by 1 (S8), the counting of the time from the start of the increasing state is started, and the first control process ends. On the other hand, if it is not the first time (S7: NO), the counting of the time from the start of the increasing state is reset to "0" (S8), and the first control process ends.

[0036] If the answer is "NO" in step S6, it is determined whether the measured time has passed the duration T2 (S10). If the duration T2 has passed (S10: YES), the target power P c is the target standard P c On the other hand, if the measured time has not elapsed the duration T2 (S10: NO), the target power P c The target power P c If the target power P is not increasing, the counted time from the start of the increasing state is "0", so the result in step S11 is "NO" and the target power P c is the target standard P c It remains 0.

[0037] The power generation forecast P2 rises sharply and exceeds the first threshold P S1 Less than the second threshold P S2 In this case, the determination in step S2 and the determination in step S6 are both "YES." In the flowchart of FIG. 2, in this case, the target power P c Increase the amount ΔP c Increase ΔP greater than 1 c The determination in step S2 is performed before step S6 so that the count can be increased by 2.

[0038] 2 is an example, and the first control process performed by the command device 13 is not limited to the above. For example, the duration T2 may be set to a sufficiently large value (for example, about 5 minutes), and steps S5 and S9 may be eliminated from the flowchart shown in FIG.

[0039] 3 to 5 are time charts showing the change in each value when a simulation of the first control process by the command device 13 is performed. FIG. 3 is an overall time chart covering 8 to 16 hours elapsed from midnight. FIGS. 4 and 5 are enlarged views of a portion of the time chart shown in FIG. 3. FIG. 4 is an enlarged view of period 1 shown in FIG. 3, and FIG. 5 is an enlarged view of period 2 shown in FIG. 3. In each diagram, the horizontal axis represents elapsed time, and the vertical axis represents power. In this simulation, the capacity of the photovoltaic power generation facility 2 is 500 kW, the maximum charging power Pch_max is 90 kW, and the load power consumption P of the load L is 100 kW. L The target power P c The target standard P c 0 is set to 10 kW. Therefore, the first threshold P S1 is 190 (= 200 - 10) kW (thick solid line P in Fig. 4(a) S1 ) and the second threshold P S2 is 280 (= 200 + 90 - 10) kW (thick solid line P in Figure 5(a) S2 (See reference).

[0040] The dashed line P shown in each figure (a) L is the load power consumption P L The dashed line P1 shown in each figure (a) indicates the time change of the actual power generation capacity P1 of the solar power generation facility 2. The solid line P2 shown in each figure (a) indicates the time change of the predicted power generation capacity P2 predicted by the prediction device 12. In this simulation, the prediction device 12 predicts the power generation capacity P1 one minute from now and outputs it as the predicted power generation capacity P2. Therefore, the solid line P2 is the same as the dashed line P1 shifted to the left by a predetermined time T1 (1 minute). The dashed line P PV is the actual output power P of solar power generation facility 2PV The solid line P shown in each figure (b) shows the time change of EV is the total charge / discharge power P EV The graph shows the change over time in the charging and discharging power P EV is a positive value in the case of discharging, but in this simulation, it is a negative value because it shows the case of charging. EV The lower limit is "-90" kW. C is the target power P c The dashed line P(t) in each figure (b) shows the change over time of the connection point power P(t).

[0041] As shown in FIG. 4, at time t1, the predicted power generation capacity P2 increases and reaches the first threshold P S1 In other words, the predicted power generation capacity P2 is greater than the first threshold P S1 Less than the first threshold P S1 Therefore, after a predetermined time T1 (1 minute), the generateable power P1 increases to the first threshold value P S1 Less than the first threshold P S1 In some cases, the node power P(t) may drop below "0", causing a reverse power flow. c By increasing the target power P c is the increase ΔP c 1 (20 kW in this simulation), and then the node power P(t) is increased to the target power P c This shows that at time t1', a predetermined time T1 after time t1, the node power P(t) decreases, but does not decrease to "0", and therefore no reverse power flow occurs.

[0042] At time t2 before the duration T2 (2 minutes) has elapsed from time t1, the predicted power generation capacity P2 increases and reaches the first threshold P S1Therefore, the command device 13 resets the count time of the increasing state to "0" to continue the increasing state. In the same manner, the count time is reset to "0" several times, and at time t3, the predicted power generation capacity P2 rises and reaches the first threshold P S1 At time t4, when the duration T2 (2 minutes) has elapsed since time t3, the target power P c is the target standard P c 0, and then the node power P(t) is set to the target power P c It has been declining in line with

[0043] Furthermore, as shown in FIG. 5, at time t5, the predicted power generation capacity P2 increases and reaches the second threshold P S2 In other words, the predicted power generation capacity P2 is greater than the second threshold P S2 Less than the second threshold P S2 Therefore, after a predetermined time T1 (1 minute), the generateable power P1 increases to the second threshold value P S2 Less than the second threshold P S2 In some cases, the node power P(t) may drop below "0", causing a reverse power flow. c By increasing the target power P c is the increase ΔP c 2 (40 kW in this simulation), and then the node power P(t) is increased to the target power P c As a result, at time t5', which is the predetermined time T1 after time t5, the node power P(t) does not decrease to "0", and no reverse power flow occurs.

[0044] At time t6 before the duration T2 (2 minutes) has elapsed from time t5, the predicted power generation capacity P2 increases and reaches the second threshold P S2 Therefore, the command device 13 resets the count time of the increasing state to "0" and continues the increasing state. At time t7, the predicted power generation capacity P2 increases and reaches the second threshold P S2At time t8, when the duration T2 (2 minutes) has elapsed since time t7, the target power P c is the target standard P c 0, and then the node power P(t) is set to the target power P c It has been declining in line with

[0045] FIG. 6 shows the load power consumption P of the load L in the simulation shown in FIGS. L 6 is a time chart showing the change in each value when only the load power consumption P L The first threshold P S1 In the case of FIG. 6, at time t1, the predicted power generation capacity P2 rises and exceeds the first threshold P S1 Less than the first threshold P S1 The target power P c is increased, and the connection point power P(t) increases. As a result, even if the connection point power P(t) decreases, it does not decrease to "0", and no reverse power flow occurs. In this way, the load power consumption P L Even if the power supply voltage is not fixed but fluctuates, reverse power flow can be prevented.

[0046] Next, the second control process will be described. The second control process is a control when the charging system B1 is separated from the power grid C and performs independent operation when a grid fault occurs. During independent operation, the generateable power P1 is equal to or less than the load power consumption P L While the power conditioner 22 of the photovoltaic power generation facility 2 is stopped, the output power P PV is "0". The power that can be generated P1 is the load power consumption P LWhen this is achieved, the power conditioner 22 starts up, and the photovoltaic power generation facility 2 becomes able to output power. As a second control process, the command device 13 checks the surplus power that will be left over after a predetermined time T1 (for example, one minute) according to the power generation prediction P2 input from the prediction device 12, and controls the EV stand 4 to charge with the surplus power. The surplus power is calculated by the power generation prediction P2 and the charge / discharge power P EV The total power consumption of the load P L It is calculated by subtracting

[0047] Specifically, the command device 13 calculates the surplus power P X (=P2+P EV -P L ) is calculated. Then, the command device 13 calculates the surplus power P X is the specified power P X_1 If the actual power generation capacity P1 is larger than the predetermined time T1, it is predicted that there will be a power surplus due to the actual power generation capacity P1 after the predetermined time T1, so the charge / discharge target, which is the target value of the input / output power (individual power) of the charger / discharger 42 of each EV stand 4, is reduced. Note that the amount of reduction in the charge / discharge target is not limited and may be a fixed value, or the surplus power P X Decreasing the charge / discharge target to "0" or less is equivalent to increasing the target value of the charging power, and the charging power to the electric vehicle 41 at the EV stand 4 increases. X_1 is not limited. X_1 is set appropriately depending on the results of simulations and experiments. X If is smaller than "0", it is predicted that the surplus power from the actual generateable power P1 will be exhausted after the predetermined time T1, so the charge / discharge target of the charger / discharger 42 of each EV stand 4 is increased or set to "0". Note that the amount of increase in the charge / discharge target is not limited. Increasing the charge / discharge target by "0" or less is equivalent to decreasing the target value of the charging power, and the charging power to the electric vehicle 41 at the EV stand 4 will decrease. Furthermore, if the charge / discharge target is set to "0", the EV stand 4 will no longer perform charging or discharging.

[0048] 7 is an example of a flowchart for explaining the second control process performed by the command device 13. The second control process is executed at predetermined timings (for example, at timings when the power generation possibility prediction P2 is input from the prediction device 12) after the charging system B1 starts the independent operation.

[0049] First, the power generation prediction P2 input from the prediction device 12 is acquired (S21). Next, the power generation prediction P2, the charge / discharge power P EV , and the load power consumption P L Based on this, the margin power P X (=P2+P EV -P L ) is calculated (S22).

[0050] Next, the surplus power P X is the specified power P X_1 It is determined whether the margin power P is greater than the margin power P (S23). X is the specified power P X_1 If it is greater (S23: YES), the charge / discharge target is decreased (S24), and the second control process ends.

[0051] In step S23, the margin power P X is the specified power P X_1 In the following cases (S23: NO), the surplus power P X It is determined whether the margin power P is smaller than "0" (S25). X If the margin power P is smaller than "0" (S25: YES), the charge / discharge target is set to "0" (S26), and the second control process ends. X is equal to or greater than "0" (S25: NO), that is, the surplus power P X is "0" or more, the specified power P X_1 In the following cases, the charge / discharge target is not changed and the second control process ends.

[0052] 7 is an example, and the second control process performed by the command device 13 is not limited to the above. For example, in step S26, the charge / discharge target may be increased. In addition, in step S25, the surplus power P Xis the specified power P X_2 It may be determined whether the predetermined power P X_2 is not limited as long as it is (0<β<α). X_2 is set appropriately according to the results of simulations and experiments.

[0053] FIG. 8 is a time chart showing the change in each value when a simulation of the second control process by the command device 13 is performed. FIG. 8(a) is a time chart in which the elapsed time from midnight is in the range of 8.5 hours to 11 hours. FIG. 8(b) is a time chart in which the elapsed time from midnight is in the range of 13 hours to 15.5 hours. In each figure, the horizontal axis indicates the elapsed time, and the vertical axis indicates the power. The various conditions of this simulation are the same as those of the simulations in FIGS. 3 to 5. However, this simulation was performed in a state where the charging system B1 was disconnected from the power grid C. The dashed straight line P shown in each figure L is the load power consumption P L The dashed line P2 in each figure shows the time change of the power generation possibility forecast P2 predicted by the forecasting device 12. The dashed line P PV is the actual output power P of solar power generation facility 2 PV The solid line P EV is the total charging and discharging power P of multiple EV stands 4 EV The graph shows the change over time in the charging and discharging power P EV is a positive value in the case of discharging, but in this simulation, it is a negative value because it shows the case of charging. EV The lower limit is "-90" kW.

[0054] As shown in FIG. 8(a), at time t9, the surplus power P X increases, and the predetermined power P X_1 When the charge / discharge target is decreased, the charge / discharge power P EV decreases (charging power increases). EV In response to the decrease in PVis increasing.

[0055] Also, as shown in FIG. 8(b), at time t10, the surplus power P X When the charge / discharge target is increased to "0", the charge / discharge power P EV is set to "0". Also, the charge / discharge power P EV As the increase in PV The charge / discharge power P EV becomes "0", and immediately after that, the surplus power P X Therefore, the margin power P X is the specified power P X_1 As the charging / discharging target is reduced, the charging / discharging power P EV is decreasing (charging power is increasing).

[0056] In the period between FIG. 8(a) and FIG. 8(b) (the time elapsed is between 11 hours and 13 hours), the predicted power generation capacity P2 becomes sufficiently large, and the charging / discharging power P EV is at the lower limit (maximum charge state), so it will not decrease any further even if the charge / discharge target decreases.

[0057] Next, the operation and effects of the power management device A1 according to this embodiment will be described.

[0058] According to this embodiment, the prediction device 12 outputs the predicted future power generation capacity as a power generation capacity prediction P2 to the command device 13. The command device 13 performs a first control process in accordance with the input power generation capacity prediction P2. In the first control process, the command device 13 performs a first control process in accordance with the power generation capacity prediction P2 when the power generation capacity prediction P2 is equal to or exceeds a first threshold P S1 Less than the first threshold P S1 When this happens, the target power P(t) of the connection point power P(t) c The node power P(t) is increased by the target power P c As a result, after the predetermined time T1, the actual generateable power P1 increases in accordance with the first threshold P S1 Less than the first threshold P S1When the power output of the solar power generation facility 2 reaches or exceeds the second threshold value P, the power output of the solar power generation facility 2 reaches or exceeds the second threshold value P. Therefore, even if the power output of the solar power generation facility 2 suddenly drops due to a sudden increase in the power output of the solar power generation facility 2, the occurrence of reverse power flow is prevented. S2 Less than the second threshold P S2 The same applies when the number of times exceeds this limit.

[0059] Furthermore, according to this embodiment, the command device 13 controls the target power P c This increasing state of the node power P(t) continues for a duration T2. ​​The duration T2 is at least longer than the predetermined time T1, and is at least twice the predetermined time T1. This allows the node power P(t) to be in an increased state when the actual generateable power P1 increases.

[0060] Furthermore, according to this embodiment, while the increasing state continues, the power generation possibility forecast P2 again becomes equal to or exceeds the first threshold value P S1 Less than the first threshold P S1 If the power P(t) exceeds this limit, the increased state is continued for a further duration T2 from that point onward. This method prevents the increased state of the node power P(t) from becoming unnecessarily long, compared to when the duration T2 is set to a large value.

[0061] Furthermore, according to this embodiment, when the charging system B1 performs an independent operation, the command device 13 performs a second control process in accordance with the input power generation prediction P2. In the second control process, the command device 13 controls the surplus power P X (=P2+P EV -P L ) is calculated. Then, the command device 13 calculates the surplus power P X is the specified power P X_1 If the target value is larger than the target value, the command device 13 reduces the charge / discharge target of each EV stand 4. In this way, the command device 13 can use the generateable power P1 for charging at the EV stand 4 without wasting it as much as possible. X is smaller than "0", the charge / discharge target of each EV stand 4 is increased to "0". As a result, the command device 13 increases the charge / discharge power PEV to "0" (reducing the charging power to "0"), it is possible to prevent the solar power generation facility 2 from being stopped due to insufficient output power. In this way, the power management device A1 balances the supply and demand of power during independent operation, and can stably supply power to the electric vehicle 41 without stopping the solar power generation facility 2.

[0062] In this embodiment, the case where each EV stand 4 is equipped with a charger / discharger 42 that not only charges but also discharges the electric vehicle 41 has been described, but this is not limited to this. Any or all of the EV stands 4 may be equipped with a charger that only charges, instead of the charger / discharger 42.

[0063] Fig. 9 is a block diagram showing the overall configuration of a charging system B2 including a power management device A2 according to the second embodiment. In Fig. 9, elements that are the same as or similar to those in the charging system B1 according to the first embodiment are given the same reference numerals, and redundant explanations will be omitted.

[0064] In the charging system B2 according to this embodiment, the power management device A2 calculates the connection point power P(t) to the target power P c The charging system B1 differs from the charging system B2 according to the first embodiment in that it calculates an index pr for controlling the connection point power P(t) to the target power P(t) and outputs a common index pr to each power equipment 5 as a command. Each power equipment 5 uses the common index pr input from the power management device A2 to calculate an individual power target, which is a target value for the individual power of the equipment itself, based on an optimization problem that has been set for each equipment. Then, it performs control so that the individual power becomes the individual power target. Each power equipment 5 autonomously controls the individual power based on the index pr, and the connection point power P(t) becomes the target power P(t) to the target power P(t). c is controlled by.

[0065] The power management device A2 includes a command device 14 instead of the command device 13. The command device 14 controls the target power P cand the node power P(t), and outputs the index pr common to each power facility 5 as a command. A description of the method for calculating the index pr will be omitted. The command device 14 also performs a first control process in accordance with the power generation forecast P2 input from the forecasting device 12 to set the target power P c The command device 14 changes the index pr by changing the input index pr, and outputs the changed index pr to each power facility 5. Each power facility 5 performs control according to the input index pr. Furthermore, during independent operation, the command device 14 stops outputting the index pr, and performs a second control process according to the power generation capacity prediction P2 input from the prediction device 12.

[0066] The solar power generation facility 2 includes a power conditioner 23 instead of the power conditioner 22. The power conditioner 23 includes a target power calculation unit 231 and a control unit 232. The target power calculation unit 231 calculates an individual power target based on a preset optimization problem using the index pr input from the command device 14. An optimization problem suitable for controlling the solar cell 21 is preset in the target power calculation unit 231. The control unit 232 controls the individual power based on the individual power target calculated by the target power calculation unit 231. In other words, the power conditioner 23 is configured by adding the target power calculation unit 231 to the power conditioner 22.

[0067] The EV stand 4 is equipped with a charger / discharger 43 instead of the charger / discharger 42. The charger / discharger 43 is configured by adding a configuration similar to that of the target power calculation unit 231 to the charger / discharger 42. An optimization problem suitable for charging and discharging the storage battery of the electric vehicle 41 is set in advance in the charger / discharger 43.

[0068] The optimization problems set for the power conditioner 23 and the charger / discharger 43 are designed to enable control according to the purpose.

[0069] In this embodiment, the prediction device 12 also outputs the predicted future power generation capacity forecast P2 to the command device 14. The command device 14 performs a first control process in accordance with the input power generation capacity forecast P2. In the first control process, the command device 14 performs a first control process in accordance with the power generation capacity forecast P2 when the power generation capacity forecast P2 is equal to or exceeds a first threshold P S1 Less than the first threshold P S1 When this happens, the target power P(t) of the connection point power P(t) c The node power P(t) is increased by the target power P c As a result, after the predetermined time T1, the actual generateable power P1 increases in accordance with the first threshold P S1 Less than the first threshold P S1 When the power output of the solar power generation facility 2 reaches or exceeds the second threshold value P, the power output of the solar power generation facility 2 reaches or exceeds the second threshold value P. Therefore, even if the power output of the solar power generation facility 2 suddenly drops due to a sudden increase in the power output of the solar power generation facility 2, the occurrence of reverse power flow is prevented. S2 Less than the second threshold P S2 The same applies when the above occurs. Furthermore, the power management device A2 according to this embodiment has a configuration common to the power management device A1, and thereby achieves the same effects as the power management device A1. Furthermore, according to this embodiment, the power management device A2 only calculates and outputs the index pr without grasping the individual state of each piece of power equipment 5, so the burden of calculation and communication is small. In other words, the power management device A2 does not need to be a high-performance, expensive device, so the initial installation cost can be reduced. Furthermore, when the charging system B2 is expanded, no major modifications to the power management device A2 are required.

[0070] The indicators pr that the power management device A2 outputs to each piece of power equipment 5 are not limited to being common. The power management device A2 may output different indicators pr for each type of power equipment 5. However, the power management device A2 outputs a common indicator pr to power equipment 5 of the same type.

[0071] The power management device according to the present invention is not limited to the above-described embodiment, and the specific configuration of each part of the power management device according to the present invention can be freely designed and modified in various ways. [Explanation of symbols]

[0072] B1, B2: charging system, A1, A2: power management device, 12: prediction device, 13, 14: command device, 2: solar power generation equipment, 21: solar cell, 22: power conditioner, 4: EV stand, 41: electric vehicle, 42: charger / discharger, 231: target power calculation unit, 232: control unit, L: load

Claims

1. A power management device is provided in a charging system including a solar power generation facility that generates power using solar cells, a plurality of power facilities including an EV stand that supplies power to an electric vehicle, and a load, for controlling connection point power, which is input / output power of the entire charging system, to a target power, Each of the power facilities includes a power control device that controls individual power, which is input / output power of the respective power facilities, a prediction device that predicts the future power generation capacity of the solar power generation facility for a predetermined time period and outputs the predicted power generation capacity; a command device that outputs a command to each of the power control devices to control the corresponding individual power; Equipped with the command device changes a target for control based on a comparison between the power generation availability forecast input from the prediction device and a power demand including power consumption of a load. Power management device.

2. the command device increases the target power when the power generation forecast changes from being less than a threshold based on the power demand to being equal to or greater than the threshold. The power management device of claim 1 .

3. the command device continues the increased state in which the target power is increased for a duration, The duration is at least twice the predetermined time. The power management device of claim 2 .

4. If the power generation possibility prediction again changes from less than the threshold to equal to or greater than the threshold while the increasing state continues, the command device continues the increasing state for the duration from that point on. The power management device of claim 3 .

5. When the charging system is disconnected from the power grid, if the surplus power calculated based on the power generation forecast and the power demand is greater than a first power, the command device increases a target value of the charging power to the electric vehicle in the power control device of the EV stand, and if the surplus power is smaller than a second power, decreases the target value of the charging power to the electric vehicle in the power control device of the EV stand. The power management device of claim 1 .

6. the command device calculates an index based on the connection point power and the target power, and outputs the index as the command; Each of the plurality of power control devices a target power calculation unit that calculates an individual power target, which is a target value of an individual power that is a control target, based on the index input from the command device and a preset optimization problem; a control unit that controls the individual power based on the individual power target; Equipped with 6. The power management device according to claim 1.

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