JP2020191698A - Power system - Google Patents

Abstract

To provide a technique for stabilizing control while making use frequencies close for the same kind of apparatuses.SOLUTION: A first power conversion apparatus 32 controls first output power from a first control object in accordance with a first control value which is derived based on a first stabilization command value for making a voltage of a DC bus 14 close to a first target value and a first control command value separate from the first stabilization command value. A second power conversion apparatus 42 controls second output power from a second control object in accordance with a second control value which is derived based on a second stabilization command value for making the voltage of the DC bus 14 close to a second target value and a second control command value separate from the second stabilization command value. In the first power conversion apparatus 32, the first target value is changed in response to a change in the first output power, and in the second power conversion apparatus 42, the second target value is changed in response to a change in the second output power.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power system in which equipment is connected to a DC bus.

A plurality of devices such as a power generation device such as a photovoltaic power generation device and a power storage device such as a stationary storage battery are used in combination with an electric power system. In order to realize this with a simple configuration and flexible operation, for example, a plurality of power converters that supply DC power to a DC bus are connected. Each power converter monitors the DC voltage in the DC bus and generates DC power based on the monitored DC voltage independently of other power converters (see, for example, Patent Document 1).

JP-A-2015-61439

When a plurality of storage batteries are connected to a DC bus, if the operation of the converter connected to each storage battery is different, a storage battery that is preferentially used is generated. As the frequency of use increases, the storage battery deteriorates faster, so that the storage battery used preferentially deteriorates more easily than other storage batteries. Since it is preferable that the degree of deterioration of the plurality of storage batteries is close, the ease of use of the plurality of storage batteries should be close to each other. On the other hand, if each converter executes discharge at the same time or charges at the same time in order to make the ease of use of the plurality of storage batteries close to each other, hunting occurs and the control becomes unstable.

The present disclosure has been made in view of these circumstances, and an object of the present invention is to provide a technique for stabilizing control while reducing the frequency of use of the same type of equipment.

In order to solve the above problems, the electric power system of a certain aspect of the present disclosure is connected to a first control target capable of performing at least one of power generation, storage, and distribution, and is also connected to a DC bus. It includes a 1 power conversion device and a second power conversion device connected to a second control target of the same type as the first control target among power generation, storage, and distribution, and also connected to a DC bus. The first power conversion device is based on a first stabilization command value for bringing the voltage of the DC bus closer to the first target value and a first control command value different from the first stabilization command value. The first output power from the first control target is controlled by the first control value derived from the above, and the second power conversion device is a second stabilization command value for bringing the voltage of the DC bus closer to the second target value. The second output power from the second control target is controlled by the second control value derived based on the second control command value different from the second stabilization command value, and the first power conversion is performed. In the device, the first target value changes according to the change in the first output power, and in the second power conversion device, the second target value changes according to the change in the second output power.

It should be noted that any combination of the above components and the conversion of the expression of the present disclosure between a method, a device, a system, a computer program, a recording medium on which a computer program is recorded, or the like is also effective as an aspect of the present disclosure. is there.

According to the present disclosure, control can be stabilized while the frequency of use of the same type of equipment is close.

It is a figure which shows the structure of the electric power system which concerns on Example 1. FIG. It is a figure which shows the structure of the power conversion apparatus which concerns on Example 1. FIG. It is a figure which shows the control rule stored in the storage part of FIG. It is a figure which shows the structure of the electric power system which concerns on Example 2. FIG. It is a figure which shows the threshold value used in the command value derivation part for stabilization of Example 2. FIG. It is a figure which shows the structure of the electric power system which concerns on Example 3. FIG. 7 (a)-(b) are diagrams showing control rules adjusted in the control device according to the third embodiment. It is a figure which shows the structure of the electric power system which concerns on Example 4. FIG.

(Example 1)
Before concretely explaining the examples of the present disclosure, the findings underlying the examples will be described. An embodiment relates to a power system in which a power conversion device is connected to each of a power generation device, a storage battery, a power system, and the like, and a plurality of power conversion devices are connected to a DC bus in a consumer. In this power system, a plurality of storage batteries are connected in parallel to the power system. A consumer is a facility that receives electric power from an electric power company or the like, such as a house, an office, a store, a factory, or a park. In the consumer, the distribution line extending from the power system is connected to the power conversion device. Further, a DC bus extends from the power conversion device, the DC bus is branched into a plurality of DC buses at a branch point, and a storage battery is connected to each of the branched DC buses. A power conversion device is connected to each of the plurality of storage batteries, and the plurality of storage batteries execute charging / discharging via the power conversion device.

In order to simplify the configuration of the power system, each power conversion device executes power control independently. When a plurality of power converters output DC power to the DC bus all at once by independent power control, the voltage of the DC bus becomes high and the power system becomes unstable. When a plurality of power converters execute power control according to the voltage of the DC bus in order to stabilize the power system, the power control takes into consideration the voltage of the DC bus, and the efficiency of the power control is lowered. In particular, when the power conversion devices connected to the storage battery perform different operations from each other, a storage battery that is preferentially charged and discharged is generated. Since the storage battery deteriorates as the number of times of charging and discharging increases, the storage battery that is preferentially charged and discharged is more likely to deteriorate than other storage batteries. On the other hand, it is preferable that the degree of deterioration of the plurality of storage batteries connected to the same DC bus is close, so that the ease of charging and discharging of the plurality of storage batteries should be close. If multiple storage batteries are charged or discharged all at once in order to make the charging and discharging of multiple storage batteries close to each other, hunting will occur in the DC bus and control will be unstable. become. In such a connection form, it is required to stabilize the control while keeping the frequency of use of the plurality of storage batteries close to each other.

FIG. 1 shows the configuration of the power system 100. The electric power system 100 is connected to the electric power system 10, and has a distribution line 12, a DC bus 14, a branch point 16, a first DC bus 18, a second DC bus 20, a first storage battery 30, a first power conversion device 32, and the like. It includes a second storage battery 40, a second power conversion device 42, a third power conversion device 50, a load 60, a first measuring device 62a collectively called a measuring device 62, a second measuring device 62b, and a third measuring device 62c. The electric power system 100 is installed in the customer. The first storage battery 30 and the first power conversion device 32 may be separate devices, but may be integrated as the first power storage device 34. The second storage battery 40 and the second power conversion device 42 may be separate devices, but may be integrated as the second power storage device 44.

The power system 10 is a commercial power source of an electric power company, for example, a single-phase three-wire 200V / 100V commercial power. The distribution line 12 extends from the power system 10 toward the inside of the customer. Since a known technique may be used for the distribution line 12, description thereof will be omitted here. A third power conversion device 50 is connected to the distribution wire 12, a DC bus 14 extends from the third power conversion device 50, and the DC bus 14 has a first DC bus 18 and a second DC bus 20 at a branch point 16. It is branched to. The first storage battery 30 and the first power conversion device 32 are connected to the first DC bus 18, and the second storage battery 40 and the second power conversion device 42 are connected to the second DC bus 20. The DC bus 14, the first DC bus 18, and the second DC bus 20 may be collectively referred to as a DC bus.

The first storage battery 30 is capable of charging and discharging electric power, and is composed of a plurality of storage battery cells connected in series or series-parallel. As the storage battery cell, a lithium ion storage battery, a nickel hydrogen storage battery, a lead storage battery, an electric double layer capacitor, a lithium ion capacitor and the like are used. An electric double layer capacitor may be used as the first storage battery 30. The second storage battery 40 is configured in the same manner as the first storage battery 30, but may have a capacity different from that of the first storage battery 30.

The first power conversion device 32 is arranged between the first storage battery 30 and the branch point 16 in the first DC bus 18. The first power conversion device 32 controls charging / discharging of the first storage battery 30. The second power conversion device 42 is arranged between the second storage battery 40 and the branch point 16 in the second DC bus 20. The second power conversion device 42 controls charging / discharging of the second storage battery 40. The configurations of the first power conversion device 32 and the second power conversion device 42 will be described later. Here, the first power conversion device 32 and the second power conversion device 42 are connected to the DC bus in parallel. Therefore, the first storage battery 30 and the second storage battery 40 are connected in parallel to each other via the first power conversion device 32, the first DC bus 18, the branch point 16, the second DC bus 20, and the second power conversion device 42. Will be done.

The first measuring device 62a to the third measuring device 62c are arranged between the branch point 16 and the third power conversion device 50 on the DC bus 14. These measuring devices 62 are voltmeters that measure the voltage value of the DC bus. The first measuring device 62a outputs the measured voltage value to the first power conversion device 32, the second measuring device 62b outputs the measured voltage value to the second power conversion device 42, and the third measuring device 62c , The measured voltage value is output to the third power converter 50.

The third power conversion device 50 converts the AC power from the distribution line 12 into DC power and outputs the DC power to the DC bus 14. Further, the third power conversion device 50 converts the DC power from the DC bus 14 into AC power and outputs the AC power to the distribution line 12. In this way, the third power conversion device 50 executes conversion between AC power and DC power.

The load 60 is arranged between the power system 10 and the third power conversion device 50 on the distribution line 12. The load 60 is a device that consumes electric power supplied via the distribution line 12. The electric power supplied via the distribution line 12 includes the electric power supplied from the electric power system 10, the electric power supplied from the first storage battery 30 via the third electric power converter 50, and the electric power supplied through the third electric power converter 50. The electric power supplied from the second storage battery 40 is included. The load 60 includes an air conditioner (air conditioner), a television receiver (television), and a lighting device. Here, one load 60 is connected to the distribution line 12, but a plurality of loads 60 may be connected to the distribution line 12.

Here, the power system 10, the first storage battery 30, the second storage battery 40, and the solar cell (not shown) can be said to be control targets capable of executing at least one of power generation, storage, and distribution. When the first storage battery 30 is called a first control target, the second power conversion device 42 is called a second control target, and the power system 10 is called a third control target. Further, the first power conversion device 32, the second power conversion device 42, and the third power conversion device 50 are collectively referred to as power conversion devices. When the power conversion device connected to the first control target is called the first power conversion device, the power conversion device connected to the second control target is called the second power conversion device and is connected to the third control target. The power conversion device is called a third power conversion device.

FIG. 2 shows the configuration of the power conversion device 200. The power conversion device 200 includes a conversion unit 210, a first control unit 220, a second control unit 230, and an input unit 240. The first control unit 220 includes a stabilization command value derivation unit 250, a control command value derivation unit 260, a control value derivation unit 270, and an instruction unit 280, and the stabilization command value derivation unit 250 includes an upper derivation unit 252. , Including the lower lead-out unit 254. The second control unit 230 includes a measurement unit 232, a target value control unit 234, and a storage unit 236. Here, the second control unit 230 is included in the power conversion device 200 that controls the control target when the power system 100 includes two or more control targets of the same type. Therefore, in the case of FIG. 1, the first power conversion device 32 and the second power conversion device 42 include a second control unit 230. On the other hand, the third power conversion device 50 does not include the second control unit 230. The power conversion device 200 is a general term for the first power conversion device 32, the second power conversion device 42, and the third power conversion device 50. Hereinafter, the case where (1) the power conversion device 200 is the third power conversion device 50 and (2) the case where the power conversion device 200 is the first power conversion device 32 or the second power conversion device 42 will be described in this order.

(1) When the power conversion device 200 is the third power conversion device 50 The conversion unit 210 is a bidirectional inverter. The conversion unit 210 converts the AC power from the distribution line 12 into DC power and outputs the DC power to the DC bus 14 at the time of forward flow. Further, the conversion unit 210 converts the DC power from the DC bus 14 into AC power and outputs the AC power to the distribution line 12 at the time of reverse power flow. The conversion unit 210 is controlled by the first control unit 220.

The input unit 240 receives the voltage value from the third measuring device 62c, that is, the voltage value of the DC bus 14. The stabilization command value derivation unit 250 stabilizes the power system to put the voltage value within the range for the power system when the voltage value comes out from a predetermined range (hereinafter referred to as "range for the power system"). Generate a conversion command value. Specifically, the upper lead-out unit 252 sets the upper threshold of the power system range (hereinafter referred to as "upper threshold for power system"), and the voltage value is higher for the power system. When it is equal to or higher than the threshold value, a command value for stabilizing the upper side of the power system for lowering the voltage value is generated. The upper lead-out unit 252 outputs the power system upper stabilization command value to the control value lead-out unit 270. The lower lead-out unit 254 sets the lower threshold of the power system range (hereinafter referred to as "lower threshold for power system"), and the voltage value is the lower threshold for power system. In the following cases, a command value for stabilizing the lower side of the power system for raising the voltage value is generated. The lower side derivation unit 254 outputs the power system lower side stabilization command value to the control value derivation unit 270.

The control command value deriving unit 260 executes control for exerting the original function of the power system 10. This control is performed, for example, in response to a request from an electric power company, a request from a VPP (Virtual Power Plant), and a request from a HEMS (Home Energy Management System) device. Since a known technique may be used for this control, description thereof will be omitted here. The control command value derivation unit 260 generates a power system control command value according to the control, and outputs the power system control command value to the control value derivation unit 270.

The control value derivation unit 270 is a power system upper stabilization command value from the upper derivation unit 252, a power system lower stabilization command value from the lower derivation unit 254, and a power system from the control command value derivation unit 260. Receives control command values. If at least one of these command values is not generated, the control value derivation unit 270 does not accept the command value. The control value derivation unit 270 generates a power system control value based on the power system upper stabilization command value, the power system lower stabilization command value, and the power system control command value. For example, the control value derivation unit 270 calculates the power system control value by calculating the sum of the power system upper stabilization command value, the power system lower stabilization command value, and the power system control command value. Generate. The control value derivation unit 270 outputs the power system control value to the instruction unit 280. The indicator unit 280 receives the power system control value from the control value derivation unit 270. The instruction unit 280 controls the conversion unit 210 by outputting the power system control value to the conversion unit 210. This corresponds to executing the power control of the power system 10.

(2) When the power conversion device 200 is the first power conversion device 32 or the second power conversion device 42 The conversion unit 210 in the first power conversion device 32 is located between the first storage battery 30 and the branch point 16 in FIG. Placed in. The conversion unit 210 is a DC-DC converter. When the first storage battery 30 is discharged, the conversion unit 210 converts the DC power from the first storage battery 30 into a DC power having a desired voltage value, and outputs the converted DC power to the first DC bus 18. Further, the conversion unit 210 converts the DC power from the first DC bus 18 into DC power having a desired voltage value when charging the first storage battery 30, and outputs the converted DC power to the first storage battery 30. To do. That is, the conversion unit 210 charges and discharges the first storage battery 30. Such control of the conversion unit 210 is performed by the first control unit 220. In the following, the description may focus on discharge.

The input unit 240 receives the voltage value measured by the first measuring device 62a. For example, voltage values are received on a regular basis. The input unit 240 outputs the voltage value to the first control unit 220. The measuring unit 232 measures the value of the DC power (hereinafter, referred to as “first output power”) output from the conversion unit 210 to the first DC bus 18. The measuring unit 232 is configured in the same manner as the measuring device 62, but for example, the measuring period in the measuring unit 232 is longer than the measuring period in the measuring device 62. The measurement unit 232 outputs the measured value of the first output power to the target value control unit 234.

The storage unit 236 stores the relationship between the first output power and the target value to be compared with the voltage value from the input unit 240 (hereinafter, referred to as “first target value”) as the first control rule. FIG. 3 shows a control rule stored in the storage unit 236. The horizontal axis indicates the output power ratio [%], and the vertical axis indicates the target value [V], specifically, the first target value. The output power ratio indicates the ratio of the first output power to the rated output power of the conversion unit 210. As the first output power increases, the output power ratio also increases, so the output power ratio may also be referred to as the first output power. As an example, in the first control rule 300, the first target value becomes A [V] when the output power ratio is 0%, becomes B [V] when the output power ratio is 50%, and becomes the output power. It is specified to be C [V] when the ratio is 100%. Here, A> B> C. Here, the rule in which the first control rule 300 is shifted toward the higher target value is the first upper threshold rule 310, and the rule in which the first control rule 300 is shifted toward the lower target value is the first upper threshold rule 310. The first lower threshold rule 320. Since the first upper threshold rule 310 and the first lower threshold rule 320 have the same inclination as the first control rule 300, they are defined so as to sandwich the first control rule 300. Return to FIG.

The target value control unit 234 receives the value of the first output power from the measurement unit 232. The target value control unit 234 refers to the first upper threshold rule 310 and the first lower threshold rule 320 stored in the storage unit 236, and refers to the first upper threshold corresponding to the value of the first output power. Get the value and the first lower threshold. Therefore, the first upper threshold value and the first lower threshold value change according to the change in the first output power. In the case of the first control rule 300 of FIG. 3, the first target value decreases as the first output power increases. The target value control unit 234 outputs the first upper threshold value to the upper lead-out unit 252 and outputs the first lower threshold value to the lower lead-out unit 254.

The stabilization command value derivation unit 250 receives the voltage value from the input unit 240, that is, the voltage value of the DC bus 14. The stabilization command value derivation unit 250 is used when a voltage value is output from a range sandwiched between the first upper threshold value and the first lower threshold value (hereinafter, referred to as “first storage battery range”). , Generates a storage battery stabilization command value to keep the voltage value within the range for the first storage battery. Specifically, the upper lead-out unit 252 generates a first upper stabilization command value for lowering the voltage value when the voltage value is equal to or higher than the first upper threshold value. The upper lead-out unit 252 outputs the first upper stabilization command value to the control value lead-out unit 270. The lower side derivation unit 254 generates a first lower side stabilization command value for raising the voltage value when the voltage value is equal to or less than the first lower side threshold value. The lower side derivation unit 254 outputs the first lower side stabilization command value to the control value derivation unit 270. It can be said that the first upper stabilization command value and the first lower stabilization command value are the first stabilization command values for bringing the voltage of the DC bus 14 closer to the first target value.

The control command value deriving unit 260 executes control for exerting the original function of the first storage battery 30. This control is performed, for example, in response to a charge request or a discharge request. Since a known technique may be used for this control, description thereof will be omitted here. The control command value derivation unit 260 generates a storage battery control command value according to the control, and outputs the storage battery control command value to the control value derivation unit 270.

The control value derivation unit 270 is a storage battery control from the first upper stabilization command value from the upper derivation unit 252, the first lower stabilization command value from the lower derivation unit 254, and the control command value derivation unit 260. Accept the command value. If at least one of these command values is not generated, the control value derivation unit 270 does not accept the command value. The control value derivation unit 270 generates a storage battery control value based on the first upper stabilization command value, the first lower stabilization command value, and the storage battery control command value. For example, the control value derivation unit 270 generates a storage battery control value by calculating the sum of the first upper stabilization command value, the first lower stabilization command value, and the storage battery control command value. .. The control value derivation unit 270 outputs the storage battery control value to the instruction unit 280. The indicator unit 280 receives the storage battery control value from the control value derivation unit 270. The indicator unit 280 controls the conversion unit 210 by outputting the storage battery control value to the conversion unit 210. This corresponds to executing the power control of the first storage battery 30.

The input unit 240 in the second power conversion device 42 receives the voltage value measured in the second measuring device 62b. The input unit 240 outputs the voltage value to the first control unit 220. The measuring unit 232 measures the value of the second output power output from the conversion unit 210 to the second DC bus 20. The measurement unit 232 outputs the measured value of the second output power to the target value control unit 234.

The storage unit 236 stores the relationship between the second output power and the target value to be compared with the voltage value from the input unit 240 (hereinafter, referred to as “second target value”) as the second control rule. For example, the first control rule 300 in the first power conversion device 32 and the second control rule in the second power conversion device 42 are the same. Here, too, the output power ratio may be referred to as the second output power. Further, the same second upper threshold rule as the first upper threshold rule 310 and the same second lower threshold rule as the first lower threshold rule 320 are also stored. The target value control unit 234 receives the value of the second output power from the measurement unit 232. The target value control unit 234 refers to the second upper threshold rule and the second lower threshold rule stored in the storage unit 236, and sets the second upper threshold corresponding to the value of the first output power. Acquire the second lower threshold. Therefore, the second upper threshold value and the second lower threshold value change according to the change in the second output power. In the case of the second control rule of FIG. 3, the second target value decreases as the second output power increases. The target value control unit 234 outputs the second upper threshold value to the upper lead-out unit 252 and outputs the second lower threshold value to the lower lead-out unit 254.

The stabilization command value derivation unit 250 receives the voltage value from the input unit 240, that is, the voltage value of the DC bus 14. The stabilization command value derivation unit 250 uses the second upper threshold value and the second lower threshold value to execute the same processing as before, thereby performing the second upper stabilization command value. And at least one of the second lower stabilization command value is generated, and they are output to the control value derivation unit 270. It can be said that the second upper stabilization command value and the second lower stabilization command value are the second stabilization command values for bringing the voltage of the DC bus 14 closer to the second target value. Since the processing of the control command value derivation unit 260, the control value derivation unit 270, and the instruction unit 280 is the same as before, the description thereof will be omitted here.

Here, the outline of the operation of the first power conversion device 32 and the second power conversion device 42 will be described with reference to FIG. In the actual processing, the first upper threshold value, the first lower threshold value, the second upper threshold value, and the second lower threshold value are adjusted, but here, for the sake of simplicity of explanation. , The process of adjusting the first upper threshold value and the second upper threshold value will be described. As an example, in the initial state, the first power conversion device 32 outputs the first output power such that the output power ratio is "100%", and the second power conversion device 42 has the output power ratio "0". It is assumed that the second output power such that "%" is output. This corresponds to the case where the output is output from the first power conversion device 32, but the output is not output from the second power conversion device 42.

Since the output power ratio measured by the measurement unit 232 of the second power conversion device 42 is "0%", the target value control unit 234 of the second power conversion device 42 corresponds to the output power ratio "0%". The second target value A [V] is used. If the voltage value received by the input unit 240 of the second power conversion device 42 is smaller than the second target value A [V], the first control unit 220 of the second power conversion device 42 is a stabilization command value derivation unit. The stabilization command value by 250 is not generated. On the other hand, the control command value deriving unit 260 generates a control command value according to the control for exerting the original function of the controlled object. Therefore, the control value derivation unit 270 determines the control value to be output to the conversion unit 210 based on the control command value generated by the control command value derivation unit 260. The first control unit 220 changes the second output power output from the conversion unit 210 of the second power conversion device 42 according to this control value. In this case, the second output power is increased. As the second output power output from the conversion unit 210 of the second power conversion device 42 increases, the voltage of the DC bus rises. As a result, the output power ratio measured by the measurement unit 232 of the second power conversion device 42 also increases, and the target value control unit 234 of the second power conversion device 42 responds to the increased output power ratio. Decrease the target value.

On the other hand, since the output power ratio of the first power conversion device 32 is "100%", the target value control unit 234 of the first power conversion device 32 has the first target value C corresponding to the output power ratio "100%". [V] is used. However, as the voltage of the DC bus rises, the voltage value received by the input unit 240 of the first power conversion device 32 increases more than before and becomes larger than the first target value. The first control unit 220 of the first power conversion device 32 reduces the first output power output from the conversion unit 210 of the first power conversion device 32. As a result, the output power ratio measured by the measurement unit 232 of the first power conversion device 32 also becomes smaller, and the target value control unit 234 of the first power conversion device 32 first responds to the reduced output power ratio. Increase the target value.

As long as the voltage value received by the input unit 240 of the second power conversion device 42 is smaller than the second target value A [V], the first control unit 220 of the second power conversion device 42 is the stabilization command value derivation unit. The stabilization command value by 250 is not generated. Therefore, the first control unit 220 increases the second output power output from the conversion unit 210 of the second power conversion device 42 based on the control command value generated by the control command value derivation unit 260. By repeating such processing, when the first target value and the second target value match and the first output power and the second output power match, the processing converges. By using the control rule shown in FIG. 3, the first power conversion device 32 and the second power conversion device 42 perform droop control.

The subject of the device, system, or method in the present disclosure comprises a computer. By executing the program by this computer, the function of the subject of the device, system, or method in the present disclosure is realized. A computer has a processor that operates according to a program as a main hardware configuration. The type of processor does not matter as long as the function can be realized by executing the program. The processor is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or an LSI (Large Scale Integration). The plurality of electronic circuits may be integrated on one chip or may be provided on a plurality of chips. A plurality of chips may be integrated in one device, or may be provided in a plurality of devices. The program is recorded on a non-temporary recording medium such as a computer-readable ROM, optical disc, or hard disk drive. The program may be stored in the recording medium in advance, or may be supplied to the recording medium via a wide area communication network including the Internet or the like.

According to this embodiment, the first target value changes according to the change of the first output power from the first power conversion device 32, and the second output power changes according to the change of the second output power from the second power conversion device 42. Since the two target values change, the first storage battery 30 and the second storage battery 40 can be operated in cooperation with each other. Further, since the first storage battery 30 and the second storage battery 40 are operated in cooperation with each other, the control can be stabilized while the frequency of use of the first storage battery 30 and the second storage battery 40 is close to each other. Further, since the voltage value of the DC bus is measured, the voltage value can be used to control the first output power and the second output power. Further, since the first control rule 300 and the second control rule are the same, the output power ratio by the first output power and the output power ratio by the second output power can be made equal. Further, when the first output power increases, the first target value decreases, and when the second output power increases, the second target value decreases. Therefore, the control of the first power conversion device 32 and the control of the second power conversion device 42 The occurrence of interference between them can be suppressed.

The outline of one aspect of the present disclosure is as follows. The power system 100 of a certain aspect of the present disclosure includes a first power conversion device 32 connected to a first control target capable of performing at least one of power generation, storage, and distribution, and also connected to a DC bus. It includes a second power conversion device 42 that is connected to a second control target of the same type as the first control target among power generation, storage, and distribution, and is also connected to a DC bus. The first power converter 32 also has a first stabilization command value for bringing the voltage of the DC bus closer to the first target value, and a first control command value different from the first stabilization command value. The first output power from the first control target is controlled by the first control value derived from the above, and the second power conversion device 42 is for the second stabilization to bring the voltage of the DC bus closer to the second target value. The second output power from the second control target is controlled by the second control value derived based on the command value and the second control command value different from the second stabilization command value, and the first In the power conversion device 32, the first target value changes according to the change in the first output power, and in the second power conversion device 42, the second target value changes according to the change in the second output power.

A measuring device 62 for measuring the voltage of the DC bus may be further provided. The measuring device 62 outputs the measured voltage.

The relationship between the first output power and the first target value in the first power conversion device 32 is the same as the relationship between the second output power and the second target value in the second power conversion device 42.

In the first power conversion device 32, when the first output power increases, the first target value decreases, and in the second power conversion device 42, when the second output power increases, the second target value decreases.

(Example 2)
Next, Example 2 will be described. The second embodiment relates to an electric power system in which a plurality of storage batteries are connected in parallel to an electric power system in a consumer as in the first embodiment. Similar to the first embodiment, the power conversion device according to the second embodiment sets a target value based on the voltage value, and controls the output power using the target value. On the other hand, in the second embodiment, unlike the first embodiment, the solar cell is connected in parallel with the storage battery. The power generation device, storage battery, and power system to which each power conversion device is connected have different roles. For example, a power generation device such as a solar cell has a role of supplying a large amount of DC power to a DC bus, and a power system has a role of stabilizing a power system. Therefore, it is required to suppress a decrease in power control efficiency while stabilizing the power system while considering the roles of these devices.

For this purpose, each power conversion device executes power conversion based on the control for stabilizing the voltage of the DC bus and the control value according to the original control of the device. As described above, the control for stabilizing the voltage of the DC bus is such that when the voltage of the DC bus comes out from a predetermined range, the voltage of the DC bus is returned within the range. .. When the voltage of the DC bus comes out from a predetermined range, the voltage of the DC bus becomes larger than the maximum value in the range or smaller than the minimum value in the range. On the other hand, the original control of the device is MPPT (Maximum Power Point Tracking) control when the device is a solar cell. In order to stabilize the power system, it is desirable to execute the control for stabilizing the voltage of the DC bus, but in order to suppress the decrease in the efficiency of the power control, it is desirable to execute the original control of the device.

In the second embodiment, the range set in each power conversion device is changed in consideration of the role of the device connected to the power conversion device. For example, in a power conversion device connected to a power system, the range is narrowed. As a result, in the power conversion device, control for stabilizing the voltage of the DC bus becomes easy to be executed. On the other hand, in a power conversion device connected to a power generation device such as a solar cell, the range is widened. As a result, it becomes difficult for the power conversion device to execute control for stabilizing the voltage of the DC bus. By changing the range set in each power conversion device, the system is stabilized and the decrease in power control efficiency is suppressed. Here, the difference from the first embodiment will be mainly described.

FIG. 4 shows the configuration of the power system 100. In addition to the configuration of FIG. 1, the power system 100 includes a fourth measuring device 62d, a solar cell 90, a fourth power conversion device 92, a branch point 94, and a third DC bus 96. The first DC bus 18 has a branch point 94 between the branch point 16 and the first power conversion device 32. At the branch point 94, the first DC bus 18 to the third DC bus 96 are branched. The solar cell 90 and the fourth power conversion device 92 are connected to the third DC bus 96. Therefore, the fourth power conversion device 92 is connected to the DC bus in parallel with the first power conversion device 32 and the second power conversion device 42.

The solar cell 90 is a renewable energy power generation device, and is connected in parallel to the first storage battery 30. The solar cell 90 directly converts light energy into electric power by utilizing the photovoltaic effect. As the solar cell 90, a silicon solar cell, a solar cell made of a compound semiconductor or the like, a dye-sensitized type (organic solar cell), or the like is used. The solar cell 90 outputs the generated DC power to the fourth power conversion device 92. The fourth power converter 92 is a DC-DC converter, converts the DC power output from the solar cell 90 into DC power having a desired voltage value, and outputs the converted DC power to the third DC bus 96. ..

The DC power output to the third DC bus 96, that is, the power generated by the solar cell 90, is combined with the first output power from the first power conversion device 32 at the branch point 94. Hereinafter, the combined power is also referred to as "first output power". Therefore, the first output power from the first power conversion device 32 also includes the power generated by the solar cell 90. The first output power at the point P between the branch point 94 and the branch point 16 in the first DC bus 18 is measured by the measuring unit 232 of the first power conversion device 32. The processing of the first power conversion device 32 following the measurement unit 232 is the same as before. Further, as the renewable energy power generation device, a fuel cell, a wind power generation device, or the like may be used instead of the solar cell 90.

The configuration of the fourth power converter 92 is the same as that in FIG. The conversion unit 210 of the fourth power conversion device 92 is a DC-DC converter. The conversion unit 210 converts the DC power from the solar cell 90 into DC power having a desired voltage value, and outputs the converted DC power to the third DC bus 96. The conversion unit 210 is controlled by the first control unit 220.

The stabilization command value derivation unit 250 receives the voltage value from the fourth measuring device 60d, that is, the voltage value of the DC bus 14. The stabilization command value derivation unit 250 is a solar cell stabilization unit for putting the voltage value within the range for solar cells when the voltage value comes out from a predetermined range (hereinafter referred to as "range for solar cells"). Generate a conversion command value. Specifically, the upper lead-out unit 252 sets an upper threshold value in the range for solar cells (hereinafter, referred to as "upper threshold value for solar cells"), and the voltage value is higher for solar cells. When it is equal to or more than the threshold value, a command value for stabilizing the upper side of the solar cell for lowering the voltage value is generated. The upper lead-out unit 252 outputs the command value for stabilizing the upper side of the solar cell to the control value lead-out unit 270. The lower lead-out unit 254 sets a lower threshold value in the range for solar cells (hereinafter referred to as "lower threshold value for solar cells"), and the voltage value is the lower threshold value for solar cells. In the following cases, a command value for stabilizing the lower side of the solar cell for raising the voltage value is generated. The lower side extraction unit 254 outputs the command value for stabilizing the lower side of the solar cell to the control value extraction unit 270.

The control command value deriving unit 260 executes control for exerting the original function of the solar cell 90. This control is MPPT control. The control command value derivation unit 260 generates a solar cell control command value according to the control, and outputs the solar cell control command value to the control value derivation unit 270.

The control value derivation unit 270 is a solar cell upper stabilization command value from the upper derivation unit 252, a solar cell lower stabilization command value from the lower derivation unit 254, and a solar cell from the control command value derivation unit 260. Receives control command values. If at least one of these command values is not generated, the control value derivation unit 270 does not accept the command value. The control value derivation unit 270 generates a solar cell control value based on the solar cell upper stabilization command value, the solar cell lower stabilization command value, and the solar cell control command value. For example, the control value derivation unit 270 calculates the solar cell control value by calculating the sum of the solar cell upper stabilization command value, the solar cell lower stabilization command value, and the solar cell control command value. Generate. The control value derivation unit 270 outputs the solar cell control value to the instruction unit 280. The indicator unit 280 receives the solar cell control value from the control value derivation unit 270. The indicator unit 280 controls the conversion unit 210 by outputting the solar cell control value to the conversion unit 210. This corresponds to performing power control of the solar cell 90.

In the following, the relationship between the upper threshold value and the lower threshold value set in the first power conversion device 32, the second power conversion device 42, the third power conversion device 50, and the fourth power conversion device 92 will be described. explain. This is the upper threshold for the power system, the lower threshold for the power system, the upper threshold for the solar cell, the lower threshold for the solar cell, the first upper threshold, and the first lower threshold. It corresponds to the relationship between the value, the second upper threshold value, and the second lower threshold value.

FIG. 5 shows the threshold value used in the stabilization command value derivation unit 250. This is shown in the same manner as in FIG. The upper threshold value for the power system and the lower threshold value for the power system are arranged so as to sandwich the target voltage value "X". An upper threshold for solar cells that is larger than the upper threshold for the power system is arranged, and a lower threshold for solar cells that is smaller than the lower threshold for the power system is arranged. These do not depend on the output power ratio. Further, the first upper threshold rule 310 is arranged between the upper threshold for the power system and the upper threshold for the solar cell, and the lower threshold for the power system and the lower threshold for the solar cell are arranged. The first lower threshold rule 320 is arranged between and. The first upper threshold rule 310 corresponds to the first upper threshold and the second upper threshold, and the first lower threshold rule 320 corresponds to the first lower threshold and the second lower threshold. Corresponds to the threshold. Since the first upper threshold rule 310 and the first lower threshold rule 320 are the same as those in FIG. 3, description thereof will be omitted here.

The interval between the upper threshold for the power system and the lower threshold for the power system indicates the "range for the power system", and the interval between the upper threshold for the solar cell and the lower threshold for the solar cell is ". The range for solar cells "is shown. Further, the interval between the first upper threshold value and the first lower threshold value indicates the "first range", and the interval between the second upper threshold value and the second lower threshold value indicates the "second range". Is shown. Further, the first range and the second range are collectively referred to as a "battery range". Therefore, the range for the power system is narrower than the range for the storage battery, and the range for the storage battery is narrower than the range for the solar cell. Further, the range for the power system is defined within the range for the storage battery, and the range for the storage battery is defined within the range for the solar cell. The lower limits of the power system range, solar cell range, and storage battery range are specified to be greater than zero volt.

Here, when the voltage value of the DC bus 14 becomes larger than the target value and reaches the upper threshold value for the power system or higher, the third power conversion device 50 reflects the command value for stabilizing the upper side of the power system. Power control is executed according to the power system control value. Therefore, the third power conversion device 50 operates so that the voltage value of the DC bus 14 approaches the target value rather than according to the request from the electric power company or the like. On the other hand, since the voltage value of the DC bus 14 has not reached the first upper threshold, the second upper threshold, and the upper threshold for the solar cell, the first power conversion device 32 and the second power conversion device 42. The fourth power conversion device 92 executes power control according to a control value in which the control command value is reflected without reflecting the upper stabilization command value. Therefore, the fourth power conversion device 92 operates so as to maximize the output power by MPPT control rather than bringing the voltage value of the DC bus 14 closer to the target value. As a result, a decrease in power control efficiency is suppressed. The first power conversion device 32 and the second power conversion device 42 are the same as the fourth power conversion device 92.

When the voltage value of the DC bus 14 becomes larger and reaches the first upper threshold value and the second upper threshold value or more, the first power conversion device 32 reflects the first upper stabilization command value. The power control is executed according to the storage battery control value, and the second power conversion device 42 executes the power control according to the storage battery control value reflecting the second upper stabilization command value. Therefore, the first power conversion device 32 and the second power conversion device 42 operate so that the voltage value of the DC bus 14 approaches the target value rather than according to the request for charge / discharge or the like. The third power converter 50 also operates in the same manner as before. On the other hand, since the voltage value of the DC bus 14 has not reached the upper threshold value for the solar cell, the fourth power conversion device 92 does not reflect the command value for stabilizing the upper side of the solar cell but reflects the command value for control. Power control is executed according to the controlled value.

When the voltage value of the DC bus 14 becomes even higher and reaches the upper threshold value for the solar cell or higher, the fourth power converter 92 follows the solar cell control value reflecting the command value for stabilizing the upper side of the solar cell. Perform power control. Therefore, the fourth power conversion device 92 operates so that the voltage value of the DC bus 14 approaches the target value rather than maximizing the output power. The first power conversion device 32, the second power conversion device 42, and the third power conversion device 50 also operate in the same manner as before. As described above, in the first power conversion device 32, the second power conversion device 42, the third power conversion device 50, and the fourth power conversion device 92, the upper threshold value and the lower threshold value are different from each other, so that the power is generated. Power control is performed so that the roles of the system 10, the solar battery 90, the first storage battery 30, and the second storage battery 40 are taken into consideration.

According to this embodiment, since the first output power from the first power converter 32 includes the power generated by the solar cell 90, the solar cell 90 is connected in parallel to the first storage battery 30. Also, it is possible to eliminate the need to change the processing of the first power conversion device 32. Further, since it is not necessary to change the processing of the first power conversion device 32, various renewable energy power generation devices can be connected to the first power conversion device 32.

Further, since the range to be compared with the voltage of the DC bus 14 is changed for each power conversion device 200, the timing for deriving the control value based on the stabilization command value can be changed for each power conversion device 200. Further, since the timing for deriving the control value based on the stabilization command value can be changed for each power converter 200, the power converter 200 that operates to stabilize the voltage of the DC bus 14 and the original purpose. A power converter 200 that operates for the purpose can coexist. Further, since the power converter 200 that operates to stabilize the voltage of the DC bus 14 and the power converter 200 that operates for the original purpose coexist, the efficiency of power control can be improved while stabilizing the system. The decrease can be suppressed.

Further, since each power conversion device 200 has a function of autonomously maintaining the DC bus 14, the system can be operated stably while maintaining the voltage of the DC bus 14 within a certain range. Further, the shorter the period for maintaining the voltage of the DC bus 14 in a certain range, the longer the time for optimally controlling the device, so that the decrease in the efficiency of power control can be suppressed. Further, since the range is different, the operation of the system can be coordinated.

Further, since the range for the power system is defined within the range for the storage battery or the range for the solar cell, the third power conversion device 50 can be preferentially operated for the stabilization of the DC bus 14. Further, since the range for the power system is defined within the range for the storage battery or the range for the solar cell, the first power conversion device 32, the second power conversion device 42, and the fourth power conversion device 92 are used for the original purpose. Can be operated. Further, since the range for the power system is defined as one value, the fluctuation of the voltage of the DC bus 14 can be reduced. Moreover, since the fluctuation of the voltage of the DC bus 14 becomes small, the system can be stabilized. Further, since the third power conversion device 50 is operated to stabilize the DC bus 14, the system can be stabilized. Further, since the fourth power conversion device 92 is operated for the original purpose, it is possible to suppress a decrease in the efficiency of power control.

(Example 3)
Next, Example 3 will be described. The third embodiment relates to an electric power system in which a plurality of storage batteries are connected in parallel to an electric power system in a consumer as in the past. So far, the output power has been controlled based on the voltage value, and the target value has been controlled based on the output power. In the third embodiment, in addition to these, the control in consideration of the remaining amount of the first storage battery 30 and the second storage battery 40 is executed. Here, the differences from the past will be mainly described.

FIG. 6 shows the configuration of the power system 100. The power system 100 includes a control device 70 in addition to the configuration of FIG. The first power conversion device 32 acquires information regarding the remaining amount of the first storage battery 30 (hereinafter, referred to as “first remaining amount”). An example of information on the remaining amount is SOC (State Of Charge). The first power conversion device 32 outputs the first remaining amount to the control device 70. The second power conversion device 42 acquires information regarding the remaining amount of the second storage battery 40 (hereinafter, referred to as “second remaining amount”). The second power conversion device 42 outputs the second remaining amount to the control device 70.

The control device 70 receives the first remaining amount and the second remaining amount. The control device 70 compares the first remaining amount and the second remaining amount. The control device 70 determines the use of the control rule shown in FIG. 3 when the difference between the first remaining amount and the second remaining amount is smaller than the threshold value. This corresponds to the fact that the first control rule 300 in the first power conversion device 32 and the second control rule in the second power conversion device 42 are the same. On the other hand, when the difference between the first remaining amount and the second remaining amount is equal to or greater than the threshold value, the control device 70 determines whether or not the first remaining amount is equal to or greater than the second remaining amount. When the first remaining amount is not equal to or more than the second remaining amount, that is, when the second remaining amount is larger than the first remaining amount, the control device 70 outputs the power from the second storage battery 40 more than the power output from the first storage battery 30. The first control rule 300 and the second control rule are adjusted so that the generated power is larger. This corresponds to adjusting the control rule so that the power output from the storage battery having the larger remaining amount becomes larger. To illustrate this adjustment, FIGS. 7 (a)-(b) are used here.

7 (a)-(b) show the control rule adjusted in the control device 70. FIG. 7A shows the first control rule 300 and the second control rule 302 when the second remaining amount is larger than the first remaining amount. The first control rule 300 and the second control rule 302 match when the output power ratio is "0%", but the inclination of the second control rule 302 is gentler than the inclination of the first control rule 300. Therefore, when the output power ratios are the same, the second target value becomes larger than the first target value, so that the second output power tends to be larger than the first output power. As before, the first upper threshold rule 310 and the first lower threshold rule 320 are defined for the first control rule 300, and the second upper threshold is defined for the second control rule 302. Value rule 312 and second lower threshold rule 322 are defined. Here, the inclinations of the first control rule 300 and the second control rule 302 are made different, but the inclinations of both are the same, and the second control rule 302 is shifted upward with respect to the first control rule 300. You may. Return to FIG.

When the first remaining amount is equal to or greater than the second remaining amount, the control device 70 performs the first control so that the power output from the first storage battery 30 is larger than the power output from the second storage battery 40. The rule 300 and the second control rule 302 are adjusted. FIG. 7B shows a first control rule 300 and a second control rule 302 when the first remaining amount is equal to or greater than the second remaining amount. The inclination of the first control rule 300 and the second control rule 302 is the same, but the second control rule 302 is shifted downward with respect to the first control rule 300. Therefore, when the output power ratios are the same, the first target value becomes larger than the second target value, so that the first output power tends to be larger than the second output power. As before, the first upper threshold rule 310 and the first lower threshold rule 320 are defined for the first control rule 300, and the second upper threshold is defined for the second control rule 302. Value rule 312 and second lower threshold rule 322 are defined. Here, the inclination of the first control rule 300 and the second control rule 302 is the same, but the inclination of the second control rule 302 may be steeper than the inclination of the first control rule 300. Return to FIG.

In the above description, the control device 70 adjusts the second control rule 302 by adjusting the inclination or the shift. However, the control device 70 may adjust the first control rule 300 by adjusting the tilt or shift. Further, the control device 70 may adjust both the first control rule 300 and the second control rule 302. That is, the control device 70 acquires the state of the first storage battery 30 and the state of the second storage battery 40, and based on the state of the first storage battery 30 and the state of the second storage battery 40, the first control rule 300 and the second Adjust control rule 302. Adjusting the first control rule 300 corresponds to adjusting the first upper threshold rule 310 and the first lower threshold rule 320. Further, adjusting the second control rule 302 corresponds to adjusting the second upper threshold rule 312 and the second lower threshold rule 322.

The control device 70 outputs the first upper threshold rule 310 and the first lower threshold rule 320 to the first power conversion device 32, and outputs the second upper threshold rule 312 and the second lower threshold. The rule 322 is output to the second power conversion device 42. The first power conversion device 32 executes the same processing as before by using the first upper threshold rule 310 and the first lower threshold rule 320, and the second power conversion device 42 performs the second processing. The same processing as before is executed by using the upper threshold rule 312 and the second lower threshold rule 322. Here, the first control rule 300 in the first power conversion device 32 and the second control rule 302 in the second power conversion device 42 are different.

According to this embodiment, the first control rule 300 and the second control rule 302 are adjusted based on the remaining amount of the first storage battery 30 and the remaining amount of the second storage battery 40. Therefore, the remaining amount of the first storage battery 30 is adjusted. And the first control rule 300 and the second control rule 302 suitable for the remaining amount of the second storage battery 40 can be used. Further, since the first control rule 300 in the first power conversion device 32 is different from the second control rule 302 in the second power conversion device 42, the control in consideration of the remaining amount of the first storage battery 30 and the second storage battery 40 is executed. it can.

The outline of one aspect of the present disclosure is as follows. The relationship between the first output power and the first target value in the first power conversion device 32 is different from the relationship between the second output power and the second target value in the second power conversion device 42.

(Example 4)
Next, Example 4 will be described. The fourth embodiment relates to an electric power system in which a plurality of storage batteries are connected in parallel to an electric power system in a consumer as in the past. In the third embodiment, the first control rule and the second control rule are adjusted. In the fourth embodiment, the server installed outside the customer adjusts the first control rule and the second control rule. Here, the differences from the past will be mainly described.

FIG. 8 shows the configuration of the power system 100. The power system 100 includes a network 80 and a server 82 in addition to the configuration of FIG. The first power conversion device 32 and the second power conversion device 42 have a communication function and are connected to the server 82 via the network 80. The server 82 is installed outside the customer. The server 82 stores various patterns of the first control rule 300 and the second control rule 302, and transmits the selected first control rule 300 and the second control rule 302. The selection of the first control rule 300 and the second control rule 302 may be made by any method, and may be the same as in the third embodiment. The first power conversion device 32 receives the first control rule 300 from the server 82, and the second power conversion device 42 receives the second control rule 302 from the server 82. That is, the first control rule 300 and the second control rule 302 are changed remotely.

Instead of the first control rule 300 and the second control rule 302, the first upper threshold rule 310, the first lower threshold rule 320, the second upper threshold rule 312, and the second lower threshold Rule 322 may be used. The first power conversion device 32 executes the same processing as before by using the first upper threshold rule 310 and the first lower threshold rule 320. Further, the second power conversion device 42 executes the same processing as before by using the second upper threshold rule 312 and the second lower threshold rule 322.

According to this embodiment, since the server 82 transmits the first control rule 300 and the second control rule 202, it is possible to easily change the control rules in the first power conversion device 32 and the second power conversion device 42. Further, since the control rules in the first power conversion device 32 and the second power conversion device 42 can be easily changed, the first power conversion device 32 and the second power conversion device 42 can perform control suitable for various states. Can be executed.

The present disclosure has been described above based on the examples. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components or combinations of each processing process, and that such modifications are also within the scope of the present disclosure. ..

In the first to fourth embodiments, the first power conversion device 32 and the second power conversion device 42 are connected to each storage battery. However, the present invention is not limited to this, and for example, the first power conversion device 32 and the second power conversion device 42 may be connected to the power system or may be connected to each solar cell. According to this modification, the degree of freedom of configuration can be improved.

In the first to fourth embodiments, the first control rule 300 is defined by the relationship between the output power ratio and the first target value, and the second control rule 202 is defined by the relationship between the output power ratio and the second target value. Will be done. However, not limited to this, for example, the first control rule 300 is defined by the relationship between the first output power and the first target value, and the second control rule 202 is defined by the relationship between the second output power and the second target value. It may be specified. According to this modification, the first output power and the second output power can be controlled to be close to each other.

In the third embodiment, the remaining amount of the first storage battery 30 is used as the state of the first storage battery 30, and the remaining amount of the second storage battery 40 is used as the state of the second storage battery 40. However, the present invention is not limited to this, and for example, the degree of deterioration of the first storage battery 30 may be used as the state of the first storage battery 30, and the degree of deterioration of the second storage battery 40 may be used as the state of the second storage battery 40. The degree of deterioration is, for example, SOH (State Of Health). In this case, the degree of deterioration is used instead of the remaining amount so far, and the control rule is adjusted so that the power output from the storage battery having the smaller degree of deterioration becomes larger. According to this modification, the degree of freedom of configuration can be improved.

In the third embodiment, the measuring device 62 and the control device 70 are arranged separately. However, the present invention is not limited to this, and for example, the measuring device 62 and the control device 70 may be integrally configured. According to this modification, the degree of freedom of configuration can be improved.

10 power system, 12 distribution line, 14 DC bus, 16 branch point, 18 1st DC bus, 20 2nd DC bus, 30 1st storage battery, 32 1st power conversion device, 34 1st power storage device, 40 2nd storage battery , 42 2nd power converter, 44 2nd power storage device, 50 3rd power converter, 60 load, 62 measuring device, 90 solar battery, 92 4th power converter, 94 branch point, 96 3rd DC bus, 100 Power system, 200 power converter, 210 converter, 220 1st control unit, 230 2nd control unit, 232 measurement unit, 234 target value control unit, 236 storage unit, 240 input unit, 250 stabilization command value derivation unit , 252 upper derivation unit, 254 lower derivation unit, 260 control command value derivation unit, 270 control value derivation unit, 280 indicator unit.

Claims (5)

A first power converter that is connected to a first control target that can execute at least one of power generation, storage, and distribution, and is also connected to a DC bus.
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, storage, and distribution, and is also connected to a DC bus.
With
The first power conversion device has a first stabilization command value for bringing the voltage of the DC bus closer to the first target value, and a first control command value different from the first stabilization command value. The first output power from the first control target is controlled by the first control value derived based on the above.
The second power conversion device has a second stabilization command value for bringing the voltage of the DC bus closer to the second target value, and a second control command value different from the second stabilization command value. The second output power from the second control target is controlled by the second control value derived based on the above.
In the first power conversion device, the first target value changes according to the change in the first output power.
In the second power conversion device, the second target value changes according to the change in the second output power.
Power system. Further equipped with a measuring device for measuring the voltage of the DC bus,
The measuring device outputs the measured voltage.
The power system according to claim 1. The relationship between the first output power and the first target value in the first power conversion device is the same as the relationship between the second output power and the second target value in the second power conversion device.
The power system according to claim 1 or 2. The relationship between the first output power and the first target value in the first power conversion device is different from the relationship between the second output power and the second target value in the second power conversion device.
The power system according to claim 1 or 2. In the first power conversion device, when the first output power increases, the first target value decreases,
In the second power conversion device, when the second output power increases, the second target value decreases.
The electric power system according to any one of claims 1 to 4.

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