Power supply equipment

Abstract

To provide a power supply facility that stably supplies DC power while taking into account the distribution of charging and discharging power as instructed with respect to individual storage batteries.SOLUTION: The power supply facility has a configuration in which a power storage device is connected to a DC bus and transfers charging and discharging power to and from the DC bus. The power storage device decreases the discharge power and / or increases the charging power of the power storage device according to an excess voltage when a measured voltage value of the DC bus exceeds a first threshold voltage.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a power supply facility for stably supplying direct current power.

Background Art

[0002] In recent years, with the progress of energy storage technology and power conversion technology, the number of power supply facilities that supply the power of energy storage devices as direct current power via a power converter has been increasing. In many cases, a plurality of energy storage devices are connected in series or in parallel.

[0003] For example, in Patent Document 1, for the purpose of providing a technique for stabilizing control while making the usage frequencies of the same type of devices close to each other, "a first power conversion device that is connected to a first control target capable of performing at least one of power generation, energy storage, and power distribution and is also connected to a DC bus, and a second power conversion device that is connected to a second control target of the same type as the first control target among power generation, energy storage, and power distribution and is also connected to the DC bus, and the first power conversion device controls the first output power from the first control target with a first control value derived based on a first stabilization command value for bringing the voltage of the DC bus close to a first target value and a first control command value different from the first stabilization command value, and the second power conversion device controls the second output power from the second control target with a second control value derived based on a second stabilization command value for bringing the voltage of the DC bus close to a second target value and a second control command value different from the second stabilization command value, and in the first power conversion device, the first target value changes in response to a change in the first output power, and in the second power conversion device, the second target value changes in response to a change in the second output power", is known to be configured in this way.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above power system, while the usage frequencies of the same type of devices are made close to each other, it is difficult to perform voltage control considering the distribution of the charge / discharge power instructed for each individual storage battery, which is a problem.

[0006] In a power supply facility where a power generation device, a power storage device, and other devices are connected to a DC bus, due to an increase or decrease in the generated power when a variable output power source such as renewable energy is used in the power generation device, and an increase or decrease in the load consumption power in other devices, the voltage of the DC bus changes, and there is a problem that the voltage value at the connection point of each device may deviate from a predetermined value or a predetermined range. When the voltage value deviates from the predetermined range, a failure of the device connected to the DC bus is caused.

[0007] In view of this problem, an object of the present invention is to provide a power supply facility that stably supplies DC power while considering the distribution of the charge / discharge power instructed for each individual storage battery.

Means for Solving the Problems

[0009] From the above In the present invention, "a power supply facility in which a power storage device is connected to a DC bus to exchange charge / discharge power with the DC bus and is connected to a power command unit in , the power command unit sets a charge / discharge command value, a charge upper limit value, and a discharge upper limit value for the power storage device, and when the power storage device is commanded the charge / discharge command value from the power command unit, the voltage of the DC bus is In a voltage range from a first threshold voltage to a voltage control upper limit voltage higher than the first threshold voltage, the charge / discharge command value to the charge upper limit value or the charge rated power of the power storage device charged Increase the power, and when the power storage device is commanded the charge / discharge command value from the power command unit, the voltage of the DC bus isIn a voltage range from a second threshold voltage lower than the first threshold voltage to a lower limit voltage for voltage control lower than the second threshold voltage, the discharge power is increased from the charge / discharge command value to the discharge upper limit value or the discharge rated power of the power storage device. added to electric power supply equipment wherein the power supply facility includes at least two of the energy storage devices, and the energy storage device discharging according to the charge / discharge command value reduces the discharge power from the charge / discharge command value such that the ratio of the change rate of the charge / discharge power in each of the energy storage devices is equal to the ratio of the charge / discharge command value, and the energy storage device charging according to the charge / discharge command value reduces the charge power from the charge / discharge command value such that the ratio of the change rate of the charge / discharge power in each of the energy storage devices is equal to the ratio of the charge / discharge command value. A power supply facility characterized by the above is provided. is set as such.

Advantages of the Invention

[0010] According to the present invention, it is possible to stably supply DC power.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, for the sake of simplicity of explanation, the efficiency of each circuit and device is assumed to be 100%.

[0013] The present invention is not limited to the following embodiments. Those skilled in the art can make various additions and changes within the scope of the present invention.

Embodiment

[0014] FIG. 1 shows a configuration example of a power supply facility according to Embodiment 1 of the present invention. The power supply facility 1 in FIG. 1 is such that a storage device 2A and a storage device 2B are connected in parallel to a DC bus 3.

[0015] The storage device 2A includes a storage battery 21A, a first power conversion circuit 22A, and a DC bus voltage measurement unit 23A. The storage device 2B includes a storage battery 21B, a first power conversion circuit 22B, and a DC bus voltage measurement unit 23B. The first power conversion circuit 22A and the first power conversion circuit 22B are respectively connected to the storage battery 21A and the storage battery 21B at one end and the DC bus 3 at the other end. Then, charging and discharging of the storage battery 21A and the storage battery 21B are performed. In this embodiment, two storage devices connected to the DC bus 3 are used, but the number of connections is not limited to two.

[0016] The storage battery 21A and the storage battery 21B are secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, for example. The storage battery 21A and the storage battery 21B may be used batteries such as recycled batteries for electric vehicles, and may have different degradation states.

[0017] FIG. 2 shows a configuration example 2 of the power supply facility according to Embodiment 1 of the present invention. In addition to the above-described power storage device, the power supply facility 1 may include a self-generated power source 41, a second power conversion circuit 42, an AC / DC conversion circuit 5, and a power command unit 6, and supply AC power to a load 9. In the present embodiment, the configuration example of FIG. 2 will be used for explanation hereinafter.

[0018] The self-generated power source 41 is a renewable energy power source such as solar power generation or wind power generation, for example. The second power conversion circuit 42 converts the generated power of the self-generated power source 41 and outputs it to the DC bus 3. When the self-generated power source 41 is a renewable energy power source, the second power conversion circuit 42 performs MPPT (Maximum Power Point Tracking) control.

[0019] The DC output terminal of the AC / DC conversion circuit 5 is connected to the DC bus 3, and the AC output terminal is connected to a distribution line 7 connected to an AC power source 8. The AC power source 8 is, for example, a commercial system. Also, an AC load 9 may be connected to the distribution line 7. The AC / DC conversion circuit 5 can perform power conversion bidirectionally, and can supply the generated power of the self-generated power source 41 and the discharge power of the power storage devices 2A and 2B to the AC power source 8 or the AC load 9, and can receive power from the AC power source 8.

[0020] The power command unit 6 commands the charge / discharge power for each of the power storage devices 2A and 2B at a fixed cycle (for example, 1 minute) by wired communication or wireless communication. The command value of the charge / discharge power is determined by the power command unit 6 using, for example, the degree of deterioration of the storage batteries 21A and 21B, the predicted generated power of the self-generated power source 41, the predicted power consumption of the AC load 10, and the unit price of electricity when the AC power source 9 is a commercial system. In the present embodiment, the command value of the charge / discharge power for the power storage device 2A is defined as the charge / discharge command value 62A, and the command value of the charge / discharge power for the power storage device 2B is defined as the charge / discharge command value 62B. Here, discharge is defined as positive and charge is defined as negative.

[0021] In addition, the power command unit 6 commands the charge upper limit power and the discharge upper limit power for each of the power storage devices 2A and 2B at a fixed cycle (e.g., 1 minute) simultaneously with the charge / discharge command values 62A and 62B. The command values of the charge upper limit power and the discharge upper limit power are determined by, for example, the degree of deterioration of the storage batteries 21A and 21B and the rated power of the first power conversion circuits 22A and 22B.

[0022] In this embodiment, the command values of the charge upper limit power and the discharge upper limit power for the power storage device 2A are defined as the charge upper limit value PCLA and the discharge upper limit value PDLA, and the command values of the charge upper limit power and the discharge upper limit power for the power storage device 2B are defined as the charge upper limit value PCLB and the discharge upper limit value PDLB. Here, the charge upper limit values PCLA and PCLB are negative, and the discharge upper limit values PDLA and PDLB are positive.

[0023] In the previous descriptions, the charge / discharge command values, the charge upper limit values, and the discharge upper limit values have been described as power [kW]. However, the power command unit 6 may command in terms of current [A] instead of power [kW]. In that case, the power command values in the subsequent descriptions correspond to the power obtained by multiplying the current command values by the measured terminal voltage value of the storage battery.

[0024] In Configuration Example 2 of the power supply facility according to Embodiment 1 of the present invention shown in FIG. 2, the generated power of the self-generated power source 41 is output to the DC bus 3 via the second power conversion circuit 42. When the self-generated power source 41 is a renewable energy power source, its generated power fluctuates, so the voltage of the DC bus 3 fluctuates. When the voltage of the DC bus 3 fluctuates and the voltage value at the connection point of the device deviates from a predetermined value or a predetermined range, failures of each device connected to the DC bus 3 are caused. Therefore, it is necessary for any circuit / device connected to the DC bus 3 to perform voltage control. In this embodiment, first, the AC / DC conversion circuit 5 controls the voltage of the DC bus 3 to the standard voltage Vn (e.g., 380V) by power conversion between the DC bus 3 and the distribution line 7.

[0025] Fig. 3 shows an example of the relationship between the DC bus voltage of each power storage device and the charge / discharge power of each power storage device in Embodiment 1 of the present invention. The charge / discharge power of the power storage device is on the horizontal axis side, the DC bus voltage is on the vertical axis side, and the dotted line indicates the relationship between the DC bus voltage and the charge / discharge power of the power storage device 2A, and the broken line indicates the relationship between the DC bus voltage and the charge / discharge power of the power storage device 2B.

[0026] As shown in Fig. 3, a first threshold voltage V1 (for example, 390 V) and a second threshold voltage V2 (for example, 370 V) are set in advance for the power storage device 2A and the power storage device 2B, and the voltage V of the DC bus 3 is measured by the DC bus voltage measurement unit 23A and the DC bus voltage measurement unit 23B. Then, when the measured voltage value V is within region 1 (when it is less than or equal to the first threshold voltage V1 and greater than or equal to the second threshold voltage V2), the first power conversion circuit 22A and the first power conversion circuit 22B are controlled according to the charge / discharge command value 62A and the charge / discharge command value 62B, and the storage batteries 21A and 21B are charged and discharged.

[0027] Here, for the first threshold voltage V1, a voltage higher than the standard voltage Vn and lower than the lowest voltage range upper limit among the voltage range upper limits of all circuits and devices connected to the DC bus 3 is set as the voltage control upper limit voltage V1L. Also, for the second threshold voltage V2, a voltage lower than the standard voltage Vn and higher than the highest voltage range lower limit among the voltage range lower limits of all circuits and devices connected to the DC bus 3 is set as the voltage control lower limit voltage V2L.

[0028] The voltage of the DC bus 3 is maintained at a constant value when (the output power of the second power conversion circuit 42)+(the discharge power of the power storage device 2A)+(the discharge power of the power storage device 2B)=(the conversion power of the AC / DC conversion circuit 5). However, the conversion power of the AC / DC conversion circuit 5 is positive for the output to the distribution line 7. Also, as described above, the power storage device 2A and the power storage device 2B have positive for discharge and negative for charge.

[0029] However, for example, in the state where the power storage devices 2A and 2B are charging and discharging at the charge / discharge command values 62A and 62B, respectively, in area 1, if the output power of the second power conversion circuit 42 increases significantly, the AC-DC conversion circuit 5 cannot convert power exceeding the rated power. Therefore, the above equation cannot be satisfied, and (the output power of the second power conversion circuit 42) + (the discharge power of the power storage device 2A) + (the discharge power of the power storage device 2B) > (the conversion power of the AC-DC conversion circuit 5) may occur. At this time, the voltage of the DC bus 3 rises from the standard voltage Vn, exceeds the first threshold voltage V1, and enters area 2.

[0030] At this time, it is necessary to control the voltage of the DC bus 3 by devices other than the AC-DC conversion circuit 5. However, when performing voltage control by the second power conversion circuit 42, the generated power of the self-generated power supply 41 will be reduced, which is not preferable because it misses the opportunity to generate power from renewable energy sources. Therefore, voltage control is performed by the power storage device 2A and the power storage device 2B. However, if each of the power storage device 2A and the power storage device 2B independently performs voltage control by feedback control or the like, the controls may interfere with each other and the voltage may become unstable. Therefore, the relationship between the voltage of the DC bus 3 and the charge / discharge power is set in advance, and voltage control is performed by a method of determining the charge / discharge power according to the measured value V of the voltage of the DC bus 3.

[0031] A voltage control upper limit voltage V1L (for example, 400 V) and a voltage control lower limit voltage V2L (for example, 360 V) are set for the power storage device 2A and the power storage device 2B. Here, the voltage control upper limit voltage V1L is higher than the first threshold voltage V1, and a voltage lower than the lowest voltage range upper limit among the voltage range upper limits of all circuits and devices connected to the DC bus 3 is set. Also, the voltage control lower limit voltage V2L is lower than the second threshold voltage, and a voltage higher than the highest voltage range lower limit among the voltage range lower limits of all circuits and devices connected to the DC bus 3 is set.

[0032] In the example of the relationship between the DC bus voltage and the charge / discharge power of each energy storage device in the first embodiment of the present invention shown in FIG. 3, assume that the charge / discharge command value 62A for supplying power to the AC load 9 is a 10 kW discharge, and the charge / discharge command value 62B is a 20 kW discharge. Also assume that the discharge upper limit value PDLA is 15 kW, the discharge upper limit value PDLB is 25 kW, the charge upper limit value PCLA is -15 kW, and the charge upper limit value PCLB is -25 kW.

[0033] At this time, if the voltage V of the DC bus 3 exists within the region 1 where it is equal to or higher than the second threshold voltage V2 (370 V) and equal to or lower than the first threshold voltage V1 (390 V), the energy storage device 2A discharges at 10 kW, and the energy storage device 2B discharges at 20 kW. Here, if the rated power of the AC / DC conversion circuit 5 is 50 kW, if the output power of the second power conversion circuit 42 is 20 kW or less, then (the output power of the second power conversion circuit 42) + (the discharge power of the energy storage device 2A) + (the discharge power of the energy storage device 2B) is less than 50 kW. Therefore, the voltage V of the DC bus 3 is maintained at the standard voltage Vn (380 V) by the voltage control of the AC / DC conversion circuit 5.

[0034] However, when the output of the self-generated power supply 41 increases and the output power of the second power conversion circuit 42 exceeds 20 kW, for example, when it becomes 30 kW, (the output power of the second power conversion circuit 42) + (the discharge power of the energy storage device 2A) + (the discharge power of the energy storage device 2B) becomes 60 kW, exceeding the rated power of the AC / DC conversion circuit 5 by 10 kW. As a result, the voltage V of the DC bus 3 rises from the standard voltage Vn (380 V), exceeds the first threshold voltage V1 (390 V), and enters the region 2.

[0035] At this time, the power storage devices 2A and 2B are operated to forcibly change the charge-discharge power in the charging direction from the control by the charge-discharge command values 62A and 62B according to the relationship between the DC bus voltage shown in FIG. 3 and the charge-discharge power of each power storage device. In FIG. 3, when the voltage V of the DC bus 3 exceeds the first threshold voltage V1 (390V) and rises to 391.4V, the power storage device 2A discharges with a discharge power reduced from 10 kW to 3.6 kW, that is, 6.4 kW, and the power storage device 2B discharges with a discharge power reduced from 20 kW to 6.4 kW, that is, 13.6 kW. That is, the total discharge power of 10 kW is reduced by the power storage device 2A and the power storage device 2B. At this time, (the output power 30 kW of the second power conversion circuit 42) + (the discharge power 6.4 kW of the power storage device 2A) + (the discharge power 13.6 kW of the power storage device 2B) = (the conversion power 50 kW of the AC-DC conversion circuit 5), so the voltage V of the DC bus 3 stabilizes at 391.4V.

[0036] Here, when the output of the self-generated power supply decreases and the output power of the second power conversion circuit 42 becomes 10 kW, the voltage of the DC bus 3 drops from 391.4V, and at the same time, the discharge power of the power storage device 2A and the power storage device 2B increases according to the relationship shown in FIG. 3. Then, when the voltage V of the DC bus 3 reaches the first threshold voltage V1 (390V), the power storage device 2A discharges at 10 kW and the power storage device 2B discharges at 20 kW. At this time, (the output power 10 kW of the second power conversion circuit 42) + (the discharge power 10 kW of the power storage device 2A) + (the discharge power 20 kW of the power storage device 2B) = 40 kW, which is equal to or less than the rated power 50 kW of the AC-DC conversion circuit 5. Therefore, the voltage V of the DC bus 3 can be controlled to the standard value Vn (380V) by the AC-DC conversion circuit 5 outputting 40 kW to the distribution line 7.

[0037] The power command unit 6 commands charge / discharge command values 62A and 62B, charge upper limit powers PCLA and PCLB, and discharge upper limit powers PDLA and PDLB for each of the power storage devices 2A and 2B at a fixed cycle (e.g., 1 minute). Therefore, the relationship between the DC bus voltage V shown in FIG. 3 and the charge / discharge power of each power storage device is updated at a fixed cycle. For example, at a subsequent time, since it is expected that the output of the self-generated power source 41 will increase, the power command unit 6 may decrease the charge / discharge command values from the charge / discharge command values 62A and 62B shown in FIG. 3.

[0038] In FIG. 3, due to an event opposite to the above, the voltage V of the DC bus may decrease and become equal to or lower than the second threshold voltage V2. In this case, according to the relationship between the DC bus voltage shown in FIG. 3 and the charge / discharge power of each power storage device, the operation may be such that the charge / discharge power is forcibly changed in the discharge direction from the control by the charge / discharge command values 62A and 62B.

[0039] FIG. 4 shows an example of the relationship between the DC bus voltage in the first embodiment of the present invention and the charge / discharge power of each power storage device after the command value is updated. Here, the charge / discharge command value 62A commanded by the power command unit 6 is updated to 5 kW discharge, and the charge / discharge command value 62B is updated to 15 kW discharge. According to the update of the command value, the relationship between the DC bus voltage and the charge / discharge power of each power storage device is updated from the relationship shown in FIG. 3 to the relationship shown in FIG. 4. When the voltage V of the DC bus 3 exceeds the first threshold voltage V1 and enters region 1 or falls below the second threshold voltage V2 and enters region 3 after the update, the power storage devices 2A and 2B change the charge / discharge power according to the relationship shown in FIG. 4.

[0040] Note that in the relationship shown in FIG. 4, among the command values of the power command unit 6, only the charge / discharge command values 62A and 62B are updated, and the charge upper limit powers PCLA and PCLB and the discharge upper limit powers PDLA and PDLB are not updated. Even when the charge upper limit powers PCLA and PCLB and the discharge upper limit powers PDLA and PDLB are updated, the relationship between the DC bus voltage and the charge / discharge power of each power storage device is updated.

[0041] FIG. 5 shows Example 2 of the relationship between the DC bus voltage and the charge / discharge power of each power storage device in Embodiment 1 of the present invention. Similar to FIG. 3, the dotted line indicates the relationship between the DC bus voltage and the charge / discharge power of the power storage device 2A, and the broken line indicates the relationship between the DC bus voltage and the charge / discharge power of the power storage device 2B.

[0042] For the power storage device 2A and the power storage device 2B, similar to FIG. 3, a voltage control upper limit voltage V1L (for example, 400 V) and a voltage control lower limit voltage V2L (for example, 360 V) are set. Here, the voltage control upper limit voltage V1L is higher than the first threshold voltage V1 and lower than the lowest voltage among the upper limits of the voltage ranges of all circuits and devices connected to the DC bus 3. Also, the voltage control lower limit voltage V2L is lower than the second threshold voltage V2 and higher than the highest voltage among the lower limits of the voltage ranges of all circuits and devices connected to the DC bus 3.

[0043] In the example of the relationship between the DC bus voltage and the charge / discharge power of each power storage device in Embodiment 1 of the present invention shown in FIG. 5, assume that the charge / discharge command value 62A for charging the power storage device is -20 kW (20 kW charging), and the charge / discharge command value 62B is -40 kW (40 kW charging). Also, assume that the discharge upper limit value PDLA is 30 kW, the discharge upper limit value PDLB is 50 kW, the charge upper limit value PCLA is -30 kW, and the charge upper limit value PCLB is -50 kW.

[0044] At this time, if the voltage V of the DC bus 3 is equal to or higher than the second threshold voltage V2 (370 V) and equal to or lower than the first threshold voltage V1 (390 V), it exists in Region 1, the power storage device 2A is charged at 20 kW, and the power storage device 2B is charged at 40 kW. Here, if the rated power of the AC / DC conversion circuit 5 is 50 kW, as long as the output power of the second power conversion circuit 42 is equal to or higher than 10 kW and equal to or lower than 110 kW, (the output power of the second power conversion circuit 42)+(the charge / discharge power of the power storage device 2A - 20 kW)+(the charge / discharge power of the power storage device 2B - 40 kW) becomes equal to or higher than -50 kW and equal to or lower than 50 kW. Therefore, the voltage V of the DC bus 3 is maintained at the standard voltage Vn (380 V) by the voltage control of the AC / DC conversion circuit 5.

[0045] However, if the output of the self-generated power supply 41 decreases and, for example, the output power of the second power conversion circuit 42 becomes 0 kW, then (output power of the second power conversion circuit 42: 0 kW) + (charge / discharge power of the energy storage device 2A: -20 kW) + (charge / discharge power of the energy storage device 2B: -40 kW) becomes -60 kW. In order to control the voltage V of the DC bus 3 to the standard voltage Vn (380 V), the AC-DC conversion circuit 5 must receive 60 kW from the distribution line 7, which exceeds the rated power of 50 kW, and the AC-DC conversion circuit 5 cannot maintain the voltage V of the DC bus 3 at the standard voltage Vn (380 V). Since the power required to maintain the voltage V at the standard voltage Vn (380 V) is insufficient by 10 kW, the voltage V of the DC bus 3 drops from the standard voltage Vn (380 V) and falls below the second threshold voltage V2 (370 V).

[0046] At this time, the energy storage device 2A and the energy storage device 2B change the charge / discharge power according to the relationship between the DC bus voltage shown in FIG. 5 and the charge / discharge power of each energy storage device from the charge / discharge command value 62A and the charge / discharge command value 62B. In FIG. 5, when the voltage V of the DC bus 3 falls below the second threshold voltage V2 (370 V) and reaches 369.3 V, the energy storage device 2A increases the charge / discharge power from -20 kW (20 kW charging) by 3.6 kW to discharge at -16.4 kW (16.4 kW charging), and the energy storage device 2B increases the charge / discharge power from -40 kW by 6.4 kW to discharge at -33.6 kW (33.6 kW charging). That is, the total charging power of the energy storage device 2A and the energy storage device 2B decreases by 10 kW. At this time, (output power of the second power conversion circuit 42: 0 kW) + (discharge power of the energy storage device 2A: -16.4 kW) + (discharge power of the energy storage device 2B: -33.6 kW) = (conversion power of the AC-DC conversion circuit 5: -50 kW), so the voltage V of the DC bus 3 stabilizes at 369.3 V. After that, even when the output of the self-generated power supply 41 increases and the output of the second power conversion circuit 42 increases, as described above, the voltage of the DC bus 3, the charge / discharge power of the energy storage device 2A, and the charge / discharge power of the energy storage device 2B are determined from the relationship between the DC bus voltage shown in FIG. 5 and the charge / discharge power of each energy storage device.

[0047] As shown in FIGS. 3, 4, and 5, the power storage devices 2A and 2B respectively set the relationship between the voltage of the DC bus 3 and the charge / discharge power of the power storage device based on the command values 62A and 62B from the power command unit 6. Thereby, the voltage control of the DC bus 3 can be implemented in consideration of the charge command value PCL and the discharge upper limit value PDL determined for each power storage device by the power command unit 6 in consideration of the above-described various conditions.

[0048] Note that, in the above, the first threshold voltage V1, the second threshold voltage V2, the voltage control upper limit voltage V1L, and the voltage control lower limit voltage V2L are respectively set for each of the power storage devices 2A and 2B, and the relationship between the DC bus voltage and the charge / discharge power of the power storage device is also set for each of the power storage devices 2A and 2B in response to various command values from the power command unit 6. However, the power command unit 6 can set all of the first threshold voltage V1, the second threshold voltage V2, the voltage control upper limit voltage V1L, the voltage control lower limit voltage V2L, and the relationship between the DC bus voltage and the charge / discharge power of each power storage device. In that case, the power command unit 6 can command the set relationship between the DC bus voltage and the charge / discharge power of each power storage device, and each power storage device can operate as described above.

[0049] The power storage devices 2A and 2B can respectively set the upper limit value of the battery terminal voltage and the lower limit value of the battery terminal voltage for the protection of the storage batteries 21A and 21B. When the terminal voltages of the storage batteries 21A and 21B exceed the upper limit value of the battery terminal voltage, the first power conversion circuits 22A and 22B stop the charging operation, and the charging of the power storage devices 2A and 2B is stopped. When the terminal voltages of the storage batteries 21A and 21B fall below the lower limit value of the battery terminal voltage, the first power conversion circuits 22A and 22B stop the discharging operation, and the discharging of the power storage devices 2A and 2B is stopped.

[0050] Also, the power storage devices 2A and 2B can respectively set the upper limit current of the battery discharge and the upper limit current of the battery charge for the protection of the storage batteries 21A and 21B. These upper limit currents can be set as the discharge upper limit value PDLA, the charge upper limit value PCLA, the discharge upper limit value PDLB, and the charge upper limit value PCLB.

[0051] The control in the above-described Embodiment 1 is executed by a control circuit (not shown) of the first power conversion circuits 22A and 22B in the power storage devices 2A and 2B. FIG. 13 is a flowchart showing the processing contents of the control circuit in this case. In the case of Embodiment 1, since the control devices in the first power conversion circuits 22A and 22B execute the same processing, they will not be distinguished hereinafter.

[0052] In the first processing step S1 of FIG. 13, various setting values related to voltage are input in advance. These are the first threshold voltage V1 (for example, 390 V), the second threshold voltage V2 (for example, 370 V), the voltage control upper limit voltage V1L (for example, 400 V), the voltage control lower limit voltage V2L (for example, 360 V), and the standard voltage Vn (380 V).

[0053] In processing step S2, command values of the charge upper limit power and the discharge upper limit power (charge upper limit value PCLA and discharge upper limit value PDLA for the power storage device 2A, or charge upper limit value PCLB and discharge upper limit value PDLB for the power storage device 2B) are input from the power command unit 6. Also, in processing step S3, a charge / discharge command value 62 (62A for the power storage device 2A and 62B for the power storage device 2B) is input from the power command unit 6. These input processes in processing steps S2 and S3 are performed, for example, at a cycle of 1 minute.

[0054] The above processing is for inputting various settings and commands necessary for executing the converter control, and hereinafter, control according to these setting values and commands is performed. Therefore, the processing after processing step S4 is performed at a shorter cycle (for example, a cycle of 10 microseconds).

[0055] First, in processing step S4, the voltage V of the DC bus is detected, for example, at a cycle of 10 microseconds. In processing step S5, the voltage V is compared with various setting first threshold voltage V1 (for example, 390V) and second threshold voltage V2 (for example, 370V) related to the voltage to determine whether the current operating voltage belongs to any of the first threshold voltage V1 (for example, 390V), second threshold voltage V2 (for example, 370V), first threshold voltage V1 (for example, 390V), second threshold voltage V2 (for example, 370V), such as operation regions 1, 2, and 3 in FIG. 3.

[0056] When the voltage measurement value V is within region 1 of FIG. 3 (when it is less than or equal to the first threshold voltage V1 and greater than or equal to the second threshold voltage V2), in processing step S6, the first power conversion circuits 22A and 22B are controlled according to the charge / discharge command values 62A and 62B, and the storage batteries 21A and 21B are charged and discharged.

[0057] When the voltage measurement value V is within region 2 of FIG. 3 (when it is greater than or equal to the first threshold voltage V1 and less than or equal to the voltage control upper limit voltage V1L), in processing step S7, according to the relationship between the DC bus voltage shown in FIG. 3 and the charge / discharge power of each energy storage device, the operation is such that the charge / discharge power is forcibly changed in the charging increase direction from the control by the charge / discharge command values 62A and 62B.

[0058] When the voltage measurement value V is within region 3 of FIG. 3 (when it is less than or equal to the second threshold voltage V1 and greater than or equal to the voltage control lower limit voltage V2L), in processing step S8, according to the relationship between the DC bus voltage shown in FIG. 3 and the charge / discharge power of each energy storage device, the operation is such that the charge / discharge power is forcibly changed in the discharging increase direction from the control by the charge / discharge command values 62A and 62B.

[0059] Note that processing steps S4 to S8 are executed for each control cycle by the repetitive processing of processing step S9, and the processing referring to the input from the power command unit is executed, for example, for each 1-minute cycle by the repetitive processing of processing step S10.

Example

[0060] In this embodiment, since the configuration example of the power supply facility is the same as that in the first embodiment, the description of the configuration example is omitted. Also, the description of the same content as in the other first embodiment is omitted as appropriate.

[0061] FIG. 6 shows an example of the relationship between the DC bus voltage and the charge / discharge power of each energy storage device in the second embodiment of the present invention. For the energy storage device 2A and the energy storage device 2B, a first threshold voltage V1 and a second threshold voltage V2 are set in advance. At this time, different values can be set for the first threshold voltage V1 and the second threshold voltage V2 in the energy storage device 2A and the energy storage device 2B. However, the first threshold voltage V1 is set to be higher than the standard voltage Vn and lower than the lowest voltage range upper limit among the voltage range upper limits of all circuits and devices connected to the DC bus 3. Also, the second threshold voltage V2 is set to be lower than the standard voltage Vn and higher than the highest voltage range lower limit among the voltage range lower limits of all circuits and devices connected to the DC bus 3.

[0062] In this embodiment, the first threshold voltage V1 is set to a common value (for example, 390 V) for the energy storage device 2A and the energy storage device 2B. On the other hand, the second threshold voltage V2 takes different values for the energy storage device 2A and the energy storage device 2B. For example, the second threshold voltage V2A of the energy storage device 2A is set to 365 V, and the second threshold voltage V2B of the energy storage device 2B is set to 370 V.

[0063] For the energy storage device 2A and the energy storage device 2B, a voltage control upper limit voltage V1L (for example, 400 V) and a voltage control lower limit voltage V2L (for example, 360 V) are set in the same manner as in the first embodiment. Also, assume that the charge / discharge command value 62A commanded by the power command unit 6 is -20 kW (20 kW charge), the charge / discharge command value 62B is -40 kW (40 kW charge), the discharge upper limit value PDLA is 30 kW, the discharge upper limit value PDLB is 50 kW, the charge upper limit value PCLA is -30 kW, and the charge upper limit value PCLB is -50 kW. At this time, the relationship between the DC bus voltage and the charge / discharge power of each energy storage device as shown in FIG. 6 is set. The standard voltage Vn of the DC bus 3 is set to 380 V as in the first embodiment.

[0064] In this embodiment, assume that the output of the self-generated power supply decreases and, for example, the output power of the second power conversion circuit 42 becomes 0 kW. At this time, (output power of the second power conversion circuit 42: 0 kW)+(charge / discharge power of the energy storage device 2A: -20 kW)+(charge / discharge power of the energy storage device 2B: -40 kW) becomes -60 kW, and since the power required to maintain the voltage V of the DC bus 3 at the standard voltage Vn is 10 kW short, the voltage V of the DC bus 3 drops from the standard voltage Vn (380 V) and falls below the second threshold voltage V2 (370 V).

[0065] At this time, the energy storage device 2A and the energy storage device 2B change the charge / discharge power from the charge / discharge command values 62A and 62B according to the relationship between the DC bus voltage shown in FIG. 6 and the charge / discharge power of each energy storage device. That is, when it falls below the second threshold voltage V2 (370 V), first only the energy storage device 2B increases (decreases the charging power from 40 kW) the charge / discharge power from -40 kW. Then, when the voltage V of the DC bus 3 drops to 368.9 V, the energy storage device 2B increases (decreases the charging power from 40 kW to 30 kW) the charge / discharge power from -40 kW to -30 kW according to the relationship shown in FIG. 6. At this time, since 368.9 V is higher than the second threshold voltage V2A, the energy storage device 2A operates with a charge / discharge power of -20 kW (charging power of 20 kW) according to the charge / discharge command value 62A. As a result, (output power of the second power conversion circuit 42: 0 kW)+(charge / discharge power of the energy storage device 2A: -20 kW)+(charge / discharge power of the energy storage device 2B: -30 kW) becomes -50 kW, and thus the voltage V of the DC bus 3 stabilizes at 368.9 V.

[0066] Fig. 7 shows Example 2 of the relationship between the DC bus voltage and the charge / discharge power of each energy storage device in Example 2 of the present invention. Here, it is assumed that both the first threshold voltage V1 and the second threshold voltage V2 take different values for the energy storage device 2A and the energy storage device 2B. For example, the first threshold voltage V1A of the energy storage device 2A is set to 390V, and the first threshold voltage V1B of the energy storage device 2B is set to 395V. Also, the second threshold voltage V2A of the energy storage device 2A is set to 365V, and the second threshold voltage V2B of the energy storage device 2B is set to 370V. Further, the charge / discharge command value 62A commanded by the power command unit 6 is 10kW (10kW discharge), the charge / discharge command value 62B is -40kW (40kW charge), the discharge upper limit value PDLA is 30kW, the discharge upper limit value PDLB is 50kW, the charge upper limit value PCLA is -30kW, and the charge upper limit value PCLB is -50kW.

[0067] Here, since the second threshold voltage V2A > the second threshold voltage V2B, when the voltage of the DC bus 3 drops from the standard value Vn to the second threshold voltage V2A, first, the energy storage device 2A changes the charge / discharge power to start controlling the voltage of the DC bus 3, and the energy storage device 2B continues to charge / discharge at the power commanded by the charge / discharge command value 62B. Then, when the voltage V of the DC bus 3 further drops from the second threshold voltage V2A to the second threshold voltage V2B, the energy storage device 2B changes the charge / discharge power in the same manner as the energy storage device 2A and starts controlling the voltage of the DC bus 3.

[0068] Also, since the first threshold voltage V1A < the first threshold voltage V1B, when the voltage V of the DC bus 3 rises from the standard value Vn to the first threshold voltage V1A, first, the power storage device 2A changes the charge / discharge power to start controlling the voltage of the DC bus 3, and the power storage device 2B continues charge / discharge at the power commanded by the charge / discharge command value 62B. Then, when the voltage V of the DC bus 3 further rises from the first threshold voltage V1A to the first threshold voltage V1B, the power storage device 2B changes the charge / discharge power in the same manner as the power storage device 2A and starts controlling the voltage of the DC bus 3. As a result, the power storage device 2B prioritizes charge / discharge according to the charge / discharge command value 62B commanded by the power command unit 6 even when the voltage V of the DC bus 3 rises or falls. Only the power storage device 2A cannot control the voltage V of the DC bus 3, and the voltage control of the DC bus 3 is performed only when the voltage V of the DC bus 3 exceeds the first threshold voltage V1B or falls below the second threshold voltage V2B.

[0069] As shown in FIGS. 6 and 7, by setting different values for the first threshold voltage V1 and the second threshold voltage V2 in the power storage devices 2A and 2B, it is possible to assign priorities for shifting to the voltage control of the DC bus 3 between the power storage devices. Thereby, for a specific power storage device 2, it is possible to perform the voltage control of the DC bus 3 after prioritizing the operation at the charge / discharge power commanded by the power command unit 6.

[0070] Note that also in this embodiment, similar to Embodiment 1, the power command unit 6 can set all the relationships between the first threshold voltage V1, the second threshold voltage V2, the voltage control upper limit voltage V1l, the voltage control lower limit voltage V2L, and the DC bus voltage and the charge / discharge power of each power storage device. In that case, the power command unit 6 commands the set relationship between the DC bus voltage and the charge / discharge power of each power storage device, and each power storage device can operate as described above.

Embodiment

[0071] In this embodiment, since the configuration example of the power supply facility is the same as that of Embodiment 1, the description of the configuration example is omitted. Also, the description of the same content as in other Embodiment 1 is omitted as appropriate.

[0072] Fig. 8 shows an example of the relationship between the DC bus voltage and the charge / discharge power of each energy storage device in Embodiment 3 of the present invention. In this embodiment, the standard voltage Vn of the DC bus 3 is set to 380V, and a common first threshold voltage V1 (390V) and a common second threshold voltage V2 (370V) are set in advance for the energy storage devices 2A and 2B. Also, the energy storage devices 2A and 2B set a voltage control upper limit voltage V1L (400V) and a voltage control lower limit voltage V2L (360V). Then, the charge / discharge command value 62A of the power command unit 6 is set to 10kW discharge, and the charge / discharge command value 62B is set to 20kW discharge. Also, the discharge upper limit value PDLA is 15kW, the discharge upper limit value PDLB is 25kW, the charge upper limit value PCLA is -15kW, and the charge upper limit value PCLB is -25kW.

[0073] In this embodiment, as shown in Fig. 8, when the voltage is equal to or higher than the first threshold voltage V1, the relationship between the DC bus voltage and the charge / discharge power of each energy storage device is set such that the energy storage device 2B with a larger charge upper limit power has a larger change in charge / discharge power with respect to the change in the DC bus voltage compared to the energy storage device 2A with a smaller charge upper limit power. Also, when the voltage is equal to or lower than the second threshold voltage V2, the relationship between the DC bus voltage and the charge / discharge power of each energy storage device is set such that the energy storage device 2B with a larger discharge upper limit power has a larger change in charge / discharge power with respect to the change in the DC bus voltage compared to the energy storage device 2A with a smaller discharge upper limit power.

[0074] The storage batteries 21A and 21B of the energy storage devices 2A and 2B may be used batteries such as recycled batteries for electric vehicles, etc. In that case, the degradation states are different. On the other hand, from the perspective of maintenance management of the power supply facility, if the degradation states of each storage battery are uniform, it is efficient because the replacement of the storage batteries can be carried out simultaneously during one maintenance inspection.

[0075] Therefore, when the power command unit 6 considers the degradation state of each storage battery and sets a smaller value for the charge upper limit power or the discharge upper limit power for the energy storage device having a storage battery with progressing degradation, the voltage of the DC bus 3 is controlled while homogenizing the degradation states of each storage battery by preferentially using the energy storage device with a larger set charge upper limit power or discharge upper limit power.

[0076] When the relationship between the DC bus voltage and the charge / discharge power of the energy storage devices shown in FIG. 8 is set for energy storage device 2A and energy storage device 2B, when the DC bus voltage V exceeds the first threshold voltage V1, energy storage device 2A and energy storage device 2B change the charge / discharge power and start voltage control. However, energy storage device 2B changes the charge / discharge power more significantly. As a result, the voltage at which the switching from discharge to charge occurs during voltage control is lower for energy storage device 2B than for energy storage device 2A. That is, it is easier for charge / discharge switching to occur in energy storage device 2B. Also, in FIG. 8, the voltage at which the charge / discharge power of energy storage device 2B reaches the charge upper limit value B is set to a value lower than the voltage control upper limit voltage, and the region for charging at the charge upper limit value B is set wide. With these settings, in energy storage device 2A and energy storage device 2B, energy storage device 2B is more likely to operate in a way that causes the storage battery to deteriorate.

[0077] In this embodiment as well, similar to Embodiment 1, the power command unit 6 can set all of the first threshold voltage V1, the second threshold voltage V2, the voltage control upper limit voltage V1L, the voltage control lower limit voltage V2L, and the relationship between the DC bus voltage and the charge / discharge power of each energy storage device. In that case, the power command unit 6 can cause each energy storage device to operate as described above by commanding the set relationship between the DC bus voltage and the charge / discharge power of each energy storage device.

Embodiment

[0078] In this embodiment, since the configuration example of the power supply facility is the same as that of Embodiment 1, the description of the configuration example is omitted. Also, the description of the same content as in other Embodiment 1 is appropriately omitted.

[0079] Fig. 9 shows an example of the relationship between the DC bus voltage and the charge / discharge power of each energy storage device in Embodiment 4 of the present invention. In this embodiment, the standard voltage Vn of the DC bus 3 is set to 380V, and a common first threshold voltage V1 (390V) and a common second threshold voltage V2 (370V) are set in advance for the energy storage device 2A and the energy storage device 2B. In addition, the energy storage device 2A and the energy storage device 2B set a voltage control upper limit voltage V1L (400V) and a voltage control lower limit voltage V2L (360V). Then, the charge / discharge command value 62A of the power command unit 6 is -20kW (20kW charge), and the charge / discharge command value 62B is -40kW (40kW charge). Also, the discharge upper limit value A is 30kW, the discharge upper limit value PDLB is 50kW, the charge upper limit value PDLA is -30kW, and the charge upper limit value B is -50kW.

[0080] The power command unit 6 commands the charge / discharge command values 62A and 62B to the energy storage device 2A and the energy storage device 2B in consideration of the capacities of the storage batteries 21A and 21B, or the rated powers of the first power conversion circuits 21A and 21B, and manages the SOC (State of Charge) of the storage batteries 21A and 21B. For example, the storage battery 21A has a capacity of 30 kWh and an SOC of 50%, the storage battery 21B has a capacity of 60 kWh and an SOC of 50%. Also, the rated power of the first power conversion circuit 21A is 30kW, and the rated power of the first power conversion circuit 21B is 60kW. Here, assuming that the output power of the second power conversion circuit 42 is 60kW, by setting the charge / discharge command value 62A to -20kW (20kW charge) and the charge / discharge command value 62B to -40kW (40kW charge), the storage batteries 21A and 21B can be charged at the same SOC increase rate.

[0081] In this way, when the power command unit 6 generates and commands the charge / discharge command values for managing the SOC of each storage battery, even if each energy storage device shifts to DC bus voltage control, it is desirable to maintain the power distribution in the charge / discharge command values and change the charge / discharge power.

[0082] Therefore, in this embodiment, the relationship between the DC bus voltage and the charge / discharge power of each energy storage device is set such that the ratio of the change rate of the charge / discharge power of each energy storage device with respect to the change in the DC bus voltage is equal to the ratio of the charge / discharge command values for each energy storage device. In FIG. 8, since the ratio of the charge / discharge command values is Energy Storage Device 2A: Energy Storage Device 2B = 1:2, the ratio of the change rate of the charge / discharge power with respect to the change in the DC bus voltage V is set to Energy Storage Device 2A: Energy Storage Device 2B = 1:2.

[0083] That is, when the voltage V of the DC bus 3 rises by 10 V from 390 V to 400 V above the first threshold voltage V1, Energy Storage Device 2A changes its charge / discharge power by 10 kW and charges at 30 kW. Therefore, when the voltage V of the DC bus 3 rises by 5 V from 390 V to 395 V, Energy Storage Device 2B changes its charge / discharge power by 10 kW and charges at 50 kW. Since the charging power of 50 kW is the upper limit charging power of Energy Storage Device 2B, the charging power of Energy Storage Device 2B does not change from 50 kW even when the voltage V of the DC bus 3 is 395 V or higher.

[0084] On the other hand, when the voltage is below the second threshold voltage V2, when the voltage V of the DC bus 3 drops by 10 V from 370 V to 360 V, Energy Storage Device 2A changes its charge / discharge power by 50 kW and discharges at 30 kW. At this time, for Energy Storage Device 2B, when the voltage V of the DC bus 3 drops by 9 V from 370 V to 361 V, the relationship between the DC bus voltage and the charge / discharge power of Energy Storage Device 2B is set so that the charge / discharge power changes by 90 kW and discharges at 50 kW. As a result, the ratio of the change rate of the charge / discharge power with respect to the change in the DC bus voltage becomes Energy Storage Device 2A: Energy Storage Device 2B = 1:2. Since the discharge power of 50 kW is equal to the discharge upper limit value B, the discharge power of Energy Storage Device 2B does not change from 50 kW even when the voltage of the DC bus 3 is less than 361 V.

[0085] Also in this embodiment, similar to Embodiment 1, the power command unit 6 can set all of the first threshold voltage V1, the second threshold voltage V2, the voltage control upper limit voltage V1L, the voltage control lower limit voltage V2L, and the relationship between the DC bus voltage and the charge / discharge power of each energy storage device. In that case, the power command unit 6 commands the set relationship between the DC bus voltage and the charge / discharge power of each energy storage device, and each energy storage device can operate as described above.

Example

[0086] Fig. 10 shows a configuration example of the power supply facility in Example 5 of the present invention. The DC bus 3 has at least one electric mobile body connection part 34. And the electric mobile body 2C is connected to the DC bus 3 via the electric mobile body connection part 34. Here, the electric mobile body connection part 34 is a cable connector branched from the DC bus 3 and is an electrical contact point between the electric mobile body 2C and the DC bus 3. The electric mobile body 2C is, for example, an electric vehicle, an electric agricultural machine, a drone, etc., and is not necessarily always provided in the power supply facility 1. The electric mobile body 2C has a storage battery 21C and a first power conversion circuit 22C, and can charge the storage battery 21C by controlling the charging power by itself through DC power supply. Also, the power stored in the storage battery 21C can be discharged in DC by the first power conversion circuit 22C. In this configuration example, it is also possible to adopt a configuration in which none of the power storage devices 2A is connected to the DC bus 3, and a plurality of electric mobile body connection parts 34 and electric mobile bodies 2C are connected to the DC bus 3.

[0087] Fig. 11 shows a second configuration example of the power supply facility in Example 5 of the present invention. One end of the first power conversion circuit 22D is connected to the DC bus 3. And an electric mobile body connection part 35 is connected to the other end. And the electric mobile body 2D having a storage battery 21D is connected to the DC bus 3 via the first power conversion circuit 22D and the electric mobile body connection part 35. Here, the electric mobile body connection part 35 is a cable connector for supplying the output of the first power conversion circuit 22D to the storage battery 21D and transmitting the power of the storage battery 21D to the first power conversion circuit 22D. The electric mobile body 2D is, for example, an electric vehicle, an electric agricultural machine, a drone, etc., and is not necessarily always provided in the power supply facility 1. The electric mobile body 2D performs charging and discharging of the storage battery 21D by controlling the charging and discharging power of the first power conversion circuit 22D.

[0088] Also in the configurations of Fig. 10 and Fig. 11, the DC bus voltage control described in Examples 1 to 4 can be implemented. That is, the power command unit 6 can handle the electric mobile body 2C and the electric mobile body 2D in the same manner as the power storage devices 2A and 2B described in Examples 1 to 4.

Embodiment

[0089] FIG. 12 shows a configuration example of the power supply facility in Embodiment 6 of the present invention. In the power supply facility 1, a power conversion circuit 33 is installed on the DC bus and divided into a first DC bus 31 and a second DC bus 32. A power storage device 2A and a power storage device 2B are respectively connected to the first DC bus 31 and the second DC bus 32.

[0090] When the self-generated power source 41 is, for example, a solar power generation facility, depending on the configuration of the solar power generation facility, the output voltage of the second power conversion circuit 42 may be high (for example, 1000V). Therefore, when implementing the configurations and voltage control described in Embodiments 1 to 5, the standard voltage of the DC bus 3, which is the voltage control target value of the AC-DC conversion circuit 5, needs to be set to a high voltage (for example, 1000V). As a result, it is necessary to increase the withstand voltage of the power storage device. However, by installing the power conversion circuit 33 and stepping down the voltage of the first DC bus 31 to which the output voltage of the second power conversion circuit 42 is applied to control the voltage of the second DC bus 32, the power storage device connected to the second DC bus 32 does not need to have a higher withstand voltage.

[0091] In addition, by using the power conversion circuit 33 as an isolated power conversion circuit, electrical insulation can be achieved between the first DC bus 31 and the second DC bus 32. When the second power conversion circuit 42 is a non-isolated power conversion circuit widely used as an MPPT converter for solar power generation, there is no electrical insulation between the first DC bus 31 and the self-generated power source 41 (solar power generation facility), but there is electrical insulation between the second DC bus 32 and the self-generated power source 41 (solar power generation facility). Thus, for example, even if a person touches a location where the second DC bus 32 is deteriorated and the conductor part is exposed, since no current path is formed from the self-generated power source 41 (solar power generation facility), which is the power source, to the human body, electric shock can be prevented.

[0092] In this embodiment, the power conversion circuit 33 always performs control to make the ratio of the primary-side voltage V1 to the secondary-side voltage V2 a constant value N during operation. That is, V1 = N × V2. Here, N = 1000 / 380. Also, the rated power of the power conversion circuit 33 is assumed to be equal to the rated power of the first power conversion circuit 2B of the power storage device 2B.

[0093] Due to the constant voltage ratio control by the aforementioned power conversion circuit 33, when the voltage V of the second DC bus 32 is the standard voltage Vn (380V), the first threshold voltage V1 (390V), the voltage control upper limit voltage V1L (400V), the second threshold voltage V2 (370V), and the voltage control lower limit voltage V2L (360V) shown in the first embodiment, the primary-side voltage of the power conversion circuit 33, that is, the voltage V of the first DC bus 31, becomes the standard voltage Vn' (1000V), the first threshold voltage V1' (1026V), the voltage control upper limit voltage V1L' (1053V), the second threshold voltage V2' (974V), and the voltage control lower limit voltage V2L' (947V), respectively.

[0094] Here, the AC-DC conversion circuit 5 sets the target value to 1000V during the voltage control of the first DC bus 31, and the power storage device 2A connected to the first DC bus 31 sets the first threshold voltage V1' to 1026V, the voltage control upper limit voltage V1L' to 1053V, the second threshold voltage V2' to 974V, and the voltage control lower limit voltage V2L' to 947V, respectively. Also, the power storage device 2B connected to the second DC bus 32 sets the first threshold voltage V1 to 390V, the voltage control upper limit voltage V1L to 400V, the second threshold voltage V2 to 370V, and the voltage control lower limit voltage V2L to 360V, respectively. And by following the other controls and operations according to the first embodiment, in the configuration example of the power supply facility in this embodiment, the same effects as those of the first embodiment can be obtained.

[0095] Note that a plurality of power storage devices may be connected to the first DC bus 31 and the second DC bus 32, respectively. The first threshold voltage V1, the voltage control upper limit voltage V1L, the second threshold voltage V2, and the voltage control lower limit voltage V2L may be set in the same manner as above.

[0096] Also, in this embodiment, the power storage devices 2A and 2B can be replaced with the configurations of the electric moving body 2C and the electric moving body connection portion 34 shown in Embodiment 5, or the configurations of the electric moving body 2D, the electric moving body connection portion 35, and the first power conversion circuit 22D, respectively.

Explanation of Reference Numerals

[0097] 1: Power supply facility 2A, 2B: Power storage device 2C, 2D: Electric moving body 21A, 21B, 21C, 21D: Storage battery 22A, 22B, 22C, 22D: First power conversion circuit 23A, 23B, 23C, 23D: DC bus voltage measurement unit 3: DC bus 31: First DC bus 32: Second DC bus 33: Power conversion circuit 34, 35: Electric moving body connection portion 41: Self-generated power source 42: Second power conversion circuit 5: AC-DC conversion circuit 6: Power command unit 7: Distribution line 8: AC power source 9: AC load

Claims

1. In a power supply facility in which a power storage device is connected to a DC bus to exchange charge and discharge power with the DC bus and is connected to a power command unit, the power command unit sets a charge and discharge command value, a charge upper limit value, and a discharge upper limit value for the power storage device, when the power storage device is commanded the charge and discharge command value from the power command unit, in a voltage range where the voltage of the DC bus is from a first threshold voltage to a voltage control upper limit voltage higher than the first threshold voltage, the charge power is increased from the charge and discharge command value to the charge upper limit value or the charge rated power of the power storage device, when the power storage device is commanded the charge and discharge command value from the power command unit, in a voltage range where the voltage of the DC bus is from a second threshold voltage lower than the first threshold voltage to a voltage control lower limit voltage lower than the second threshold voltage, the discharge power is increased from the charge and discharge command value to the discharge upper limit value or the discharge rated power of the power storage device, which is a power supply facility, the power supply facility includes at least two of the power storage devices, the power storage device discharging according to the charge and discharge command value reduces the discharge power from the charge and discharge command value so that the ratio of the change rate of the charge and discharge power in each power storage device is equal to the ratio of the charge and discharge command value, the power supply facility is characterized in that the power storage device charging according to the charge and discharge command value reduces the charge power from the charge and discharge command value so that the ratio of the change rate of the charge and discharge power in each power storage device is equal to the ratio of the charge and discharge command value.

2. The power supply facility according to claim 1, the power supply facility includes at least two of the power storage devices, when the voltage of the DC bus is higher than the first threshold voltage, for the power storage device with a larger charge upper limit value, the absolute value of the change rate of the charge and discharge power with respect to the change in the voltage of the DC bus is increased by reducing the discharge power and / or increasing the charge power from the charge and discharge command value, When the voltage of the DC bus is lower than the second threshold voltage, the power storage device increases the discharge power and / or decreases the charge power from the charge / discharge command value so that the absolute value of the change rate of the charge / discharge power with respect to the change in the voltage of the DC bus becomes larger for the power storage device with the larger discharge upper limit value. A power supply facility characterized by this.

3. The power supply facility according to claim 1 or claim 2, The power command unit sets and commands the first threshold voltage, the second threshold voltage, the discharge power of the power storage device that decreases according to the voltage exceeding the first threshold voltage when the measured voltage value of the DC bus exceeds the first threshold voltage and / or the charge power of the power storage device that increases, and the discharge power of the power storage device that increases according to the voltage that has fallen when the measured voltage value has fallen below the second threshold voltage and / or the charge power of the power storage device that decreases, When the measured voltage value exceeds the first threshold voltage, the power storage device changes the charge / discharge power based on the command to decrease the discharge power of the power storage device and / or increase the charge power of the power storage device, When the measured voltage value falls below the second threshold voltage, the power storage device changes the charge / discharge power based on the command to increase the discharge power of the power storage device and / or decrease the charge power of the power storage device. A power supply facility characterized by this.

4. The power supply facility according to any one of claims 1 to 3, The DC bus includes an electric moving body connection part, The power storage device is an electric moving body connected to the electric moving body connection part and capable of charging from the DC bus or discharging to the DC bus. A power supply facility characterized by this.

5. The power supply facility according to any one of claims 1 to 4, The power supply facility includes a power conversion circuit, The power conversion circuit is installed in the middle of the DC bus, divides the DC bus into a first DC bus and a second DC bus, The energy storage device is connected to the first DC bus or the second DC bus, The power conversion circuit is characterized in that it controls the ratio of the voltage of the first DC bus to the voltage of the second DC bus to a constant value.

6. The power supply facility according to claim 5, The power conversion circuit takes electrical insulation between the first DC bus and the second DC bus. The power supply facility is characterized by this.

7. The power supply facility according to claim 6, The charging upper limit value and the discharging upper limit value are set from the terminal voltage of the storage battery included in the energy storage device, the upper limit value of the current that can be charged to the storage battery, and the upper limit value of the current that can be discharged from the storage battery. The power supply facility is characterized by this.

8. The power supply facility according to claim 7, The charging upper limit value and the discharging upper limit value are set from the power command unit. The power supply facility is characterized by this.

9. The power supply facility according to any one of claims 5 to 8, The charge / discharge command value, the charging upper limit value, and the discharging upper limit value are values related to power. The power supply facility is characterized by this.

10. The power supply facility according to any one of claims 5 to 9, The charge / discharge command value, the charging upper limit value, and the discharging upper limit value are values related to current. The power supply facility is characterized by this.

Images