JP2006129585A - Controller for dc distribution system, and transformer controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a load with stable DC power by keeping the voltage of a DC system within a specified value, even if power down or sudden power ripple such as sudden change of a load, etc. occurs in a DC distribution system. <P>SOLUTION: A group 1 of individual small-capacity dispersed power units or a group 2 of power storage devices are provided with individual controllers so as to detect the range of small voltage ripple of a DC distribution system thereby suppressing it. This controller controls the voltage of a DC system, making use of the power flow control between it and an AC system 7 by means of an AC system interconnector 3 only when these groups of small-capacity devices can not support it by themselves and it becomes relatively large voltage ripple. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is used for a DC distribution system control device and a DC distribution system in which a plurality of distributed power supply devices, a plurality of power storage devices, an AC system interconnection device, and a plurality of load voltage regulators are connected to a DC distribution system. It relates to a suitable converter control device.

  The DC distribution system is a DC distribution system that can directly distribute DC power to a DC load from a DC distributed power supply device such as a fuel cell or a DC power storage device such as a storage battery without going through an AC system or an AC / DC converter ( DC power distribution system).

  The configuration of such a system, as disclosed in Patent Documents 1 to 3, etc., distributes a distributed power source, a power storage unit, and an AC system via a DC / DC converter and an AC / DC converter, respectively. Connected to DC distribution system.

  On the other hand, as a control of such a system, in Patent Document 2, an AC grid interconnection device is controlled according to surplus / insufficient power of the DC grid using a power flow control means. Patent Document 3 discloses a technique for controlling an AC system interconnection device and a distributed power source according to surplus / insufficient power of a DC system using a communication unit from a common control unit. That is, in any case, surplus / insufficient power as a whole system is determined, and the AC grid interconnection device and the distributed power supply device are controlled based on the result.

Japanese Patent Laid-Open No. 2003-204682 (FIG. 1 and others) JP-A-6-327146 (FIG. 1 and others) JP 2002-271997 A (Claim 1 and others)

  In the prior art, when a sudden power fluctuation occurs due to a drop in some of the distributed power supplies or a sudden change in load, the control from the common control unit is not in time, and the voltage of the DC distribution system drops temporarily. There was a fear that stable DC power could not be supplied to the load.

  Therefore, the object of the present invention is to control a DC distribution system that can maintain a DC system voltage within a specified value and supply stable DC power to a load even if a sudden power fluctuation such as a power loss or a sudden load change occurs. To provide an apparatus.

  Another object of the present invention is to provide a converter control device suitable for realizing a DC power distribution system capable of supplying stable DC power to a load.

  In a preferred embodiment of the present invention, there is provided a first voltage control means for controlling a DC / DC converter corresponding to one of the distributed power supply and the power storage unit so that the voltage of the DC power distribution system approaches the rated voltage. On the other hand, the AC / DC converter that controls the interconnection with the AC system is controlled to prevent further deviation when the voltage of the DC distribution system deviates from the rated voltage by the first difference. Voltage control means is provided.

  Here, the first voltage control means uses a voltage control system (AVR) that feeds back the voltage of the DC distribution system detected in the vicinity of the distributed power source or the power storage unit, using the rated voltage of the DC distribution system as a voltage command value. It is desirable to provide. The second voltage control means includes a voltage control system (AVR) that controls the AC / DC converter so as to suppress further increase when the voltage of the DC distribution system rises by the first difference. When the detection voltage of the DC power distribution system falls below the first difference, the AC / DC converter is controlled to increase the power flow from the AC system to the DC power distribution system according to the magnitude of the drop. It is desirable to provide a power control system (APR).

  Further, in a preferred embodiment of the present invention, the distributed power source and the power storage unit other than the one among the plurality of distributed power sources and power storage units are such that the voltage of the DC distribution system is smaller than the first difference from the rated voltage. Third voltage control means for controlling the corresponding DC / DC converter is individually provided to prevent further deviation when the second difference is deviated. Here, the third voltage control means includes a voltage control system (AVR) that operates when the voltage of the DC distribution system rises by the second difference, and the voltage of the DC distribution system drops by exceeding the second difference. Then, a power control system (APR) that increases the power flow from the distributed power source or the power storage unit to the DC power distribution system according to the magnitude of the drop can be provided. Alternatively, the third voltage control means includes a voltage control system (AVR) that operates when the voltage of the DC distribution system decreases by the second difference, and the voltage of the DC distribution system increases beyond the second difference. In some cases, a power control system (APR) that increases power flow from the DC power distribution system to the distributed power source or the power storage unit according to the magnitude of the increase can be provided.

  According to a preferred embodiment of the present invention, the DC power of a distributed power supply device and / or a power storage device composed of a plurality of small-capacity devices is maximized even if a sudden power fluctuation such as a power loss or a sudden load change occurs. It can be used effectively as much as possible, and the DC system voltage can be maintained within a specified value and stable DC power can be supplied to the load.

  Other objects and features of the present invention will become apparent from the following description of the embodiments.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of the overall configuration of a control device for a DC power distribution system according to a first embodiment of the present invention. The DC power distribution system includes a distributed power supply device group 1, a power storage device group 2, an AC grid interconnection device 3, and a load voltage adjustment device group 4. These are linked by a DC distribution system 5 to perform DC / DC conversion, or This is a system that directly distributes AC / DC converted DC power to loads 8A and 8B. In the distributed power supply device group 1, distributed power supplies 12A and 12B such as fuel cells are connected to the DC power distribution system 5 through DC / DC converters 11A and 11B, respectively, and the DC power supply side voltage V1A is connected by the individual control devices 100A and 100B. , V1B and / or DC power P1A, P1B are individually controlled.

  In the power storage device group 2, power storage units 22A and 22B such as a lead storage battery, a sodium sulfur battery, and an electric double layer capacitor are connected to the DC power distribution system 5 through DC / DC converters 21A and 21B, respectively. . Then, the individual control devices 200A and 200B individually control the system side DC voltages V2A and V2B and / or the DC powers P2A and P2B.

  In the AC grid interconnection device 3, the AC grid 7 is linked to the DC distribution system 5 via the AC / DC converter 31, and the system side DC voltage V 3 and / or the DC power P 3 is individually supplied by the individual control device 300. Control.

  In the load voltage adjusting device group 4, the loads 8A and 8B are connected to the DC distribution system 5 via DC / DC converters 41A and 41B, respectively, and the load side DC voltages V41A and V41B are respectively connected to the individual control devices 400A and 400B. Control individually. Also, the system side DC voltages are V4A and V4B, and the DC power is P4A and P4B.

  The overall control device 500 collects information such as operation status, voltage, current, etc. of each terminal via an electric or optical cable, or a communication network 6 such as radio, and gives a control command based on these information to each individual control device. Transmit and control the entire system centrally and optimally.

  Next, individual control function blocks of the distributed power supply device group 1 will be described.

  FIG. 2 is a control function block diagram of the individual control devices of the distributed power supply device group 1. Here, the individual control device 100A is shown as a representative, but 100B, 100C,. First, the power command value P1REFA, the voltage command value V1REFA, the voltage fluctuation detection level VK1A, and the start / stop command S1A necessary for control are taken in via the communication network 6. Further, the detected values of the system side DC current I11A and the DC voltage V1A are taken in from the current detector 13A and the voltage detector 14A, and the system side DC power P1A is obtained by the multiplication unit 105A.

  The voltage maintaining unit 101A obtains the output P1REF2A from the DC voltage V1A and the voltage fluctuation detection level VK1A.

  In the power control system, the power command value P1REFA and the output P1REF2A of the voltage maintaining unit 101A are added by the adder 102A, and the lower limit is limited to zero and the upper limit is limited to P1REFMA by the limiter 103A. The power command value corrected in this way is compared with the DC power feedback value P1A by the subtraction unit 104A, and the power control unit (APR) 106A has, for example, proportional integration (PI) so that their deviation becomes zero. Use the control to adjust its output.

  On the other hand, in the voltage control system, the deviation between the voltage command value V1REFA and the DC voltage feedback value V1A is obtained by the subtraction unit 107A, and the deviation is zero in the voltage control unit 108A in the same manner using proportional integration (PI) control or the like. Adjust the output so that As for the outputs of the power control unit 106A and the voltage control unit 108A, the smaller value is selected by the minimum value selection unit 109A and becomes the command value of the converter control unit 110A. The converter control unit 110A controls the DC / DC converter 11A based on the command value to adjust the power flow between the distributed power source 12A such as a fuel cell and the DC distribution system 5.

  The concept of the control system configured as described above is as follows. First, in a state where the voltage of the DC distribution system 5 is close to the rated value VR, only one of the plurality of distributed power sources and power storage units connected to the DC system 5 is rated voltage by the voltage control unit (AVR). A voltage control function (first voltage control means) is provided, and power control is performed for the others. However, when the voltage of the DC system tries to deviate from the rated value beyond the predetermined value (second difference), other distributed power sources and power storage units maintain the voltage added to their individual power control units. Depending on the function of the unit, or the voltage control unit which has been in standby works, voltage fluctuation is suppressed (third voltage control means works).

  Next, the characteristics of the control device based on this idea will be described first from the distributed power supply device group 1.

  FIG. 3 shows the characteristics of the individual control devices of the distributed power supply device group 1 of FIG. In the figure, the vertical axis represents the DC voltage V1A, the horizontal axis represents the DC power P1A, the solid line represents the voltage command value V1REFA, the power command value P1REFA, the output P1REF2A of the voltage maintaining unit 101A, and the power command maximum value P1REFMA, Represents the operating point of the power supply at normal times.

  FIG. 6A shows characteristics when power control is performed. First, an electric power control system (APR) is formed so that the rated power is obtained when the voltage of the DC system is within the range of the second difference (smaller than the first difference described later) from the rated value. To do. On the other hand, if the voltage of the DC system tries to deviate from the rated value beyond the second difference, the third voltage control means for controlling the corresponding DC / DC converter is individually provided so as to prevent further deviation. In preparation. Details are described below.

  Now, the power command value P1REFA is set to the rated power value, and the voltage command value V1REFA is set to be higher than the rated DC voltage VR. On P1REFA. Here, when the DC voltage V1A falls below the voltage fluctuation detection level VK1A (second difference), the voltage maintaining unit 101A adds the correction value P1REF2A corresponding to the lowered amount to the power command value P1REFA and increases it. ing. Therefore, power is supplied to the DC distribution system 5 within the range up to the power allowable limit value P1REFMA of the distributed power source 12A to compensate for the voltage drop. Further, the voltage V1A of the DC distribution system 5 does not increase beyond the set voltage command value V1REFA (corresponding to the second difference) by the function of the voltage control unit (AVR) 108A. The voltage holding function in FIG. 3 (A) is used here to control the corresponding DC / DC converter so as to prevent further deviation when the second difference (smaller than the first difference) is shifted. No. 3 voltage control means.

  On the other hand, FIG. 5B shows characteristics when voltage control is entrusted, that is, when the first voltage control means (AVR) is formed. This time, power command value P1REFA is set to power command maximum value P1REFMA, and voltage command value V1REFA is set to rated value VR. As a result, the operating point in the steady state is on the voltage command value V1REFA by the function of the minimum value selection unit 109A.

  As described above, the power command value P1REFA, the voltage command value V1REFA, and the differential voltage VK1A that decreases from the rated voltage VR can be arbitrarily set for the distributed power supply devices (12A, 11A, and 100A). Therefore, with these appropriate settings according to the role, first, as shown in FIG. 3A, a voltage control function (first voltage) to the rated voltage VR entrusted to other distributed power supply devices and power storage devices. The function as a backup for holding the voltage fluctuation of the DC distribution system that could not be maintained by the control means) within the set range of the second relatively small differential voltage can be exhibited. Alternatively, as shown in FIG. 3B, it is possible to function as a distributed power supply device having a voltage control function (first voltage control means) to a single rated voltage VR.

  Next, the individual control device of the power storage device group 2 will be described.

  FIG. 4 is a control function block diagram of the individual control device of the power storage device group 2. Here, the individual control device 200A is shown as a representative, but 200B, 200C,. 2 is different from the individual control functional block of the distributed power supply device group 1 in that the power storage device group 2 can perform charge / discharge operation. Therefore, the lower limit value of the limiter unit 203A is set to −P2REFMA, and 209A is set to the maximum value selection unit. It is that. Others are the same as those in FIG. 2 and can be easily understood by changing the head of each code from 1 to 2, so that duplicated explanation is avoided.

  FIG. 5 shows the characteristics of the individual control devices of the power storage device group 2 of FIG. In the figure, the vertical axis indicates the DC voltage V2A, the horizontal axis indicates the DC power P2A, the solid line indicates the voltage command value V2REFA, the power command value P2REFA, the output P2REF2A of the voltage maintaining unit 201A, and the power command maximum value ± P2REFMA. Represents the operating point of the power storage device during steady state.

  FIG. 6A shows characteristics when power control is performed. The power command value P2REFA is set to the rated power value, and the voltage command value V2REFA is set to be lower than the rated DC voltage VR (by the second difference). Is on the power command value P2REFA. Here, when the DC voltage V2A increases beyond the voltage fluctuation detection level (corresponding to the second difference) VK2A, the voltage maintaining unit 201A adds the correction value P2REF2A corresponding to the increase to the negative power command value P2REFA. In the negative direction. Therefore, the power is absorbed from the DC distribution system 5 within the range up to the allowable power acceptance limit value -P2REFMA of the storage unit 22A, and the voltage rise is suppressed. Further, due to the function of the voltage control unit (AVR) 208A, the voltage V2A of the DC distribution system 5 does not drop beyond the voltage command value V2REFA set low (only by the second difference).

  On the other hand, FIG. 5B shows characteristics when voltage control is entrusted. This time, power command value P2REFA is set to power command maximum value−P2REFMA, and voltage command value V2REFA is set to rated value VR. As a result, the operating point in the steady state is on the voltage command value V2REFA by the function of the maximum value selection unit 209A.

  Since these power storage units 22A, 22B and the like can control power supply or absorption on both sides of the DC distribution system 5, the DC distribution system can be controlled by taking in and out the power based on the characteristics shown in FIG. This is suitable as first voltage control means for maintaining the voltage 5 at the rated voltage VR. Therefore, the first voltage control means is entrusted to one device in the power storage device group 2, and the other distributed power supply device group 1 and the power storage device group 2 are allowed to execute power control in a steady state and have a direct current distribution. It is desirable to use as the third voltage control means based on the characteristics of FIGS. 3A and 5B for preventing the voltage of the system 5 from deviating beyond the second difference.

  Next, the individual control function of the AC grid interconnection device 3 will be described.

  FIG. 6 is a control function block diagram of the individual control device of the AC grid interconnection device 3. The only difference from the individual control block of the distributed power supply device group 1 in FIG. 2 is that the upper and lower limit values of the limiter unit 303 are ± P3REFM. Others are the same as those in FIG. 2, and the head of each code is changed from 1 to 3, and it is assumed that there is one AC system interconnection device 3. Therefore, only the A at the end is deleted, and their functions are easily understood. it can.

  FIG. 7 shows the characteristics of the individual control device of the AC grid interconnection device 3 of FIG. In the figure, the vertical axis indicates the DC voltage V3, the horizontal axis indicates the DC power P3, the solid line indicates the voltage command value V3REF and the power command value P3REF, the output P3REF2 of the voltage maintaining unit 301, and the power command maximum value ± P3REFM. Represents the operating point at the steady state of the AC grid interconnection device.

  FIG. 6A shows characteristics when power control is performed. The power command value P3REF is set to the rated power value, and the voltage command value V3REF is set higher than the rated DC voltage VR by the first difference, so that the operating point in the steady state is on the power command value P3REF. Here, when the DC voltage V3 falls below the voltage fluctuation detection level (corresponding to the first difference) VK3, the correction value P3REF2 corresponding to the fall is added to the power command value P3REF in the output P3REF2 of the voltage maintaining unit. And increase it. Therefore, power is supplied to the DC distribution system 5 within the range up to the power allowable limit value P3REFM of the AC grid interconnection device to compensate for the voltage drop. Further, the voltage control unit (AVR) 308 prevents the voltage V3 of the DC distribution system 5 from increasing beyond the voltage command value V3REF set higher by the first difference.

  Here, the first difference is larger than the second difference. For example, if the allowable voltage fluctuation of the DC distribution system is ± 10%, it is about ± 9%, and the second voltage control means as the final backup It is desirable to use as.

  On the other hand, FIG. 5B shows the characteristics when it is assumed that the voltage control as the first voltage control means, which is not used in the embodiment of the present invention, is entrusted. The power command value P3REF is set to the power command maximum value P3REFM, and the voltage command value V3REF is set to the rated value VR. As a result, the operating point in the steady state can be set on the voltage command value V3REF by the function of the minimum value selection unit 109A.

  6 and 7, AVR and APR are configured in a form corresponding to FIGS. 2 and 3, and their outputs are selected by the minimum value selection unit, but in a form corresponding to FIGS. The same function can be achieved by configuring AVR and APR and selecting their outputs by the maximum value selection unit. That is, the AC / DC converter 31 and the voltage command V3REF are input, and the voltage control system (AVR) 308 using the detection voltage V3 on the DC side of the AC / DC converter 31 as a feedback value and the power command P3REF are input. The power flow P3 from the DC system 5 to the AC / DC converter 31 is used as a feedback value. When the detection voltage V3 on the DC side rises above a predetermined value, the power depends on the magnitude of the rise. A power control system (APR) 306 including a voltage maintenance function system (voltage maintenance unit) 301 that increases a command, and a larger one of the voltage control system (AVR) 308 and the power control system (APR) 306 according to the larger output A control device 300 for controlling the AC / DC converter 31 is provided.

  As a result, it can be easily understood that the power control characteristic similar to that shown in FIG.

  As described above, the power command value P3REF, the voltage command value V3REF, and the first differential voltage VK3 from the rated voltage VR to the descending side or the ascending side are arbitrarily set in the AC grid interconnection device (7, 31, 300). it can. Therefore, with these appropriate settings, voltage fluctuations in the DC distribution system that could not be maintained in the distributed power supply device group or the power storage device group can be made to function as a final backup for holding at a desired voltage level.

  Next, individual control of the load voltage adjusting device group will be described.

  FIG. 8 is a control function block diagram of the individual control devices of the load voltage adjusting device group 4. Here, the individual control device 400A is shown as a representative, but 400B, 400C,. First, the voltage command value V4REFA and the start / stop command S4A necessary for control are taken in via the communication network 6. Further, the load side DC voltage V41A is taken into the control device 400A via the voltage detector 44A, and the deviation from the voltage command value V4REFA is obtained by the subtractor 407A. The voltage control unit (AVR) 408A controls the DC / DC converter 41A through the converter control unit 410A using, for example, proportional integration (PI) control so that the deviation becomes zero. That is, this constitutes a simple voltage control system (AVR) that controls the load voltage V41A to be the voltage command value V4REFA.

  FIG. 9 is a characteristic diagram seen from the DC power distribution system side of the individual control device of the load voltage adjusting device group 4 of FIG. In the figure, the vertical axis represents the system side DC voltage V4A, the horizontal axis represents the DC power P4A, the solid line represents the characteristics of the load side DC voltage control, and the ◯ represents the operating point of the load voltage regulator at the steady state. Since the load voltage adjustment device group 4 always controls the DC voltage V41A on the load side to be constant, it can be expressed as a characteristic in which the power value changes according to the power consumption of the load 8A when viewed from the DC system side. it can. Further, when considering the power sale (reverse power flow) from the load side, the characteristic range extends to the first quadrant of FIG. 9, that is, the power generation region.

  Finally, the operation of one embodiment of the present invention will be described.

  FIG. 10 is an example of a voltage control operation of the DC power distribution system according to the embodiment of the present invention. From the left, FIG. 7A shows the power control characteristics of the distributed power supply device group 1 shown in FIG. 3A, the power and voltage control characteristics of the power storage device group 2 shown in FIG. 5, and FIG. It is the voltage control characteristic of AC system interconnection apparatus 3 electric power control characteristic, and the load voltage regulator apparatus group 4 of FIG. The DC voltage on the vertical axis is represented by the voltage at the representative terminal of each device. Further, since the DC power on the horizontal axis is assumed to be a plurality of small-capacity devices for the distributed power supply device group 1, the power storage device group 2, and the load voltage adjustment device group 4, the sum of the DC powers. It is represented by Σ. The thick solid line represents the control characteristics of each terminal, and the circles represent the operating points of each device group during steady state.

  Here, the function as the first voltage control means (AVR) toward the rated voltage VR of the DC distribution system 5 is applied to the power storage unit 22A, the DC / DC converter 21A and its individual control device 200A in FIG. It shows the case of entrusting.

  FIG. 4A shows the backup operation of each device when the first distributed power supply is dropped and the generated power P1A is insufficient, and will be described in order.

  First, when the two distributed power sources 12A and 12B are healthy, they are operating with the characteristics a and b, and these are in charge of the electric power P1A + P1B shown in the figure. Further, the two power storage units 22A and 22B are also responsible for the power P2A + P2B shown in the figure due to the characteristics c and d, respectively. Furthermore, the AC grid interconnection device 31 is in a standby state due to the characteristic e. On the other hand, the loads 8A and 8B connected to the DC power distribution system 5 are consuming the illustrated power P4A + P4B.

  Here, it is assumed that the first distributed power supply 12A is dropped and the generated power P1A is small or zero. According to the assumption in the DC power distribution system 5, the individual control device 200A of the power storage device group 2 responsible for the first voltage control means (AVR function) to the rated voltage VR is indicated by the arrow f along the characteristic c. So as to increase the output power. In addition, the second distributed power supply 12B that is healthy in the distributed power supply device group 1 has an arrow g on its characteristic b as the voltage drops below the set value VK1B (= VK1A) corresponding to the second difference. Increase the generated power along. Moreover, backup is also started in the power storage unit 22B that does not take charge of voltage control to the rated voltage VR in the power storage device group 2. That is, the AVR control system operates with a voltage drop below the voltage command value V2REFB (= V2REFA) set to a lower value (corresponding to the second difference) in FIG. The discharge power is increased along the line to try to support the voltage.

  These individual controls operate quickly, and if the voltage fluctuation falls within this range, the backup operation of the AC grid interconnection device 31 is unnecessary and does not operate.

  However, it is assumed that the plurality of distributed power supply device groups 1 and the power storage device groups 2 that are small and efficient can not be supported, and the voltage of the DC distribution system 5 is lower than the set value VK3 corresponding to the first difference. Then, by the function of the voltage maintaining unit 301 in the power control unit (APR) of the AC grid interconnection device 31, the power flow from the AC grid 7 to the DC distribution grid 5 is increased along the arrow j on the characteristic e. .

  In this way, the individual control device 300 of the AC grid interconnection device 3 operates as the final backup only when the insufficient power exceeds the total capacity of the plurality of distributed power supply device groups 1 and the power storage device groups 2. The power is interchanged from the AC system to the DC system to maintain the DC voltage.

  FIG. 10B shows the backup operation of each device when the power consumption ΣP4 of the load decreases rapidly. First, the individual control device 200A of the power storage device group 2 performing voltage control narrows down the DC power P2A along the arrow k on the characteristic c, and further operates in the charging (power absorption) direction to rate the voltage. Maintain the value VR. When the surplus power of the DC system exceeds the power command maximum value −P2REFMA, the voltage starts to rise. First, when the voltage command V1REFA set, for example, several percent higher, of the distributed power source 12A is reached, the generated power is narrowed along the arrow m on the characteristic a by the AVR operation. Next, when the set voltage VK2B of the individual control device 200B of the power storage device group 2 is reached, the discharge power is narrowed down on the characteristic d along the arrow n, and further, the voltage rises by operating in the charging (power absorption) direction. Suppress. When the voltage further rises and reaches the set voltage command value V1REFB of the second distributed power supply 12B, the generated power is narrowed down along the characteristic p on the characteristic b along the arrow p.

  These individual controls operate quickly, and if the voltage fluctuation falls within this range, the backup operation of the AC grid interconnection device 31 is unnecessary and does not operate.

  However, it is assumed that the plurality of distributed power supply device groups 1 and the power storage device groups 2 that are small and efficient can not be supported and exceed the voltage command value V3REF set higher in the DC distribution system 5. Then, the voltage control unit (AVR) of the AC grid interconnection device 31 works, increases the power flow to the AC grid 7 along the arrow q on the characteristic e, and suppresses the voltage rise of the DC distribution grid 5. .

  In this way, only when the surplus power narrows the generated power of the plurality of distributed power supply device groups 1 and exceeds the total capacity that can be absorbed by the power storage device group 2, the AC grid interconnection device as a final backup. The three individual control devices 300 operate, and the DC voltage is maintained by absorbing power from the DC system to the AC system.

  In the above embodiment, as a method of setting the voltage fluctuation detection level and the voltage command value at the time of power control, for example, if the maximum voltage fluctuation range of the DC system is defined as ± 10% of the rated DC voltage VR, the distributed power supply device group 1. For the power storage device group 2, for example, a voltage difference detection level and a voltage command value at the time of power control are set by providing a stepwise difference around ± 5% so that a device with a fast output response can operate with priority. It is desirable to set. In addition, since each device has a small capacity, as many units as possible are within the specified value, taking into account voltage ripple generated by switching of the DC / DC converter and voltage drop due to the resistance of the DC distribution system 5. It is desirable to set it so that it can operate. On the other hand, the voltage fluctuation detection level of the AC grid interconnection device 3 and the voltage command value at the time of power control are larger than the set values of the distributed power supply device group 1 and the power storage device group 2 from the position of final backup, for example, ± 8 to 9% is set so that it can be maintained within the specified value ± 10%.

  According to the above embodiment, in a DC power distribution system including a distributed power source, a power storage unit, and an AC grid interconnection device, a plurality of distributed power sources and power storage units can be used in the event of sudden power fluctuations such as power loss or sudden load change. The system voltage can be maintained within a specified value by the unit, and stable DC power can be supplied to the load.

1 is an overall configuration block diagram of a DC power distribution system according to a first embodiment of the present invention. FIG. 2 is a control function block diagram of individual control devices of the distributed power supply device group 1 of FIG. 1. FIG. 3 is a power-voltage characteristic diagram of an individual control device of the distributed power supply device group 1 of FIG. 2. The control function block diagram of the separate control apparatus of the electric power storage apparatus group 2 of FIG. FIG. 5 is a power-voltage characteristic diagram of an individual control device of the power storage device group 2 of FIG. 4. The control function block diagram of the separate control apparatus of the alternating current grid connection apparatus 3 of FIG. FIG. 7 is a power-voltage characteristic diagram of the individual control device of the AC grid interconnection device 3 of FIG. 6. FIG. 2 is a control function block diagram of an individual control device of a load voltage adjusting device group 4 in FIG. 1. FIG. 9 is a power-voltage characteristic diagram of an individual control device of the load voltage adjusting device group 4 of FIG. 8. An example figure of voltage control operation of a direct-current power distribution system by one example of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Distributed power supply device group, 2 ... Power storage device group, 3 ... AC system interconnection device, 4 ... Load voltage regulator device group, 5 ... DC distribution system, 6 ... Communication network, 7 ... AC system, 8A, B ... Load, 11A, 11B, 21A, 21B, 41A, 41B ... DC / DC converter, 31 ... AC / DC converter, 100A, 100B, 200A, 200B, 300, 400A, 400B ... Individual control device, 12A, 12B ... Distributed power source, 22A, 22B ... Power storage unit, 500 ... Overall control device, 13A, 23A, 33 ... Current detector, 14A, 24A, 34, 44A ... Voltage detector, 101A, 201A, 301 ... Voltage maintenance unit, 103A , 203A, 303 ... power command limiter unit, 106A, 206A, 306 ... power control unit, 108A, 208A, 308, 408A ... voltage control unit, 109A, 309 ... Small value selecting unit, 209A ... maximum value selection unit, 110A, 210A, 310,410A ... converter control unit.

Claims (11)

  A distributed power source that generates DC power and / or a power storage unit that charges and discharges DC power, and a DC / DC that is connected between the distributed power source and / or power storage unit and the DC power distribution system and controls power flow between them. In a DC power distribution system comprising a DC converter and an AC system interconnection device that includes an AC / DC converter and connects the DC power distribution system to an AC system and controls power flow between them, the distributed power source and / or A first voltage control provided corresponding to one of the power storage units and controlling the corresponding DC / DC converter so as to bring the detected voltage of the DC distribution system close to the rated voltage of the DC distribution system. And a second voltage control means for controlling the AC / DC converter so as to prevent further deviation when the detected voltage of the DC distribution system deviates from the rated voltage by the first difference. Directly characterized by The control device of the power distribution system.   2. The voltage according to claim 1, wherein the first voltage control means uses the rated voltage of the DC distribution system as a voltage command value and feeds back the voltage of the DC distribution system detected in the vicinity of the distributed power source and / or the power storage unit. A control device for a DC power distribution system, comprising a control system (AVR).   The voltage control for controlling the AC / DC converter according to claim 1, wherein the second voltage control means controls the AC / DC converter so as to suppress further increase when the detection voltage of the DC distribution system increases by the first difference. When the detected voltage of the system (AVR) and the DC distribution system falls below the first difference, the power flow from the AC system to the DC distribution system is increased according to the magnitude of the decrease. A control device for a DC power distribution system, comprising: a power control system (APR) for controlling an AC / DC converter.   2. A plurality of distributed power sources and / or power storage units connected to the DC power distribution system according to claim 1, and a plurality of DC / DC converters respectively corresponding to the distributed power sources and / or power storage units. A control device for a DC power distribution system.   5. The distributed power source and / or power storage unit other than the one among a plurality of distributed power sources and / or power storage units according to claim 4, wherein the detected voltage of the DC distribution system is smaller than the first difference from the rated voltage. 3. A control apparatus for a DC power distribution system, comprising third voltage control means for individually controlling a corresponding DC / DC converter so as to prevent further deviation when the second difference is deviated.   6. The voltage control system (AVR) that operates when the detected voltage of the DC distribution system rises by the second difference, and the detected voltage of the DC distribution system is the second voltage control means according to claim 5. And a power control system (APR) that increases power flow from the distributed power source and / or power storage unit to the DC distribution system according to the magnitude of the drop when the difference falls below the difference. Control device for DC power distribution system.   6. The voltage control system (AVR) that operates when the detected voltage of the DC distribution system drops by the second difference, and the detected voltage of the DC distribution system is the second voltage control means according to claim 5. A power control system (APR) that increases the power flow from the DC power distribution system to the distributed power source and / or the power storage unit according to the magnitude of the increase when the difference exceeds the difference is provided. Control device for DC power distribution system.   A DC / DC converter and a voltage command are input, a voltage control system (AVR) having a detection voltage of one DC system connected to the DC / DC converter as a feedback value, and a power command are input. The power flow from the DC / DC converter to the DC system is used as a feedback value, and when the detection voltage of the DC system drops below a predetermined value, the power command is increased according to the magnitude of the drop. A power control system (APR) including a voltage maintenance function system, and a control device that controls the DC / DC converter according to a smaller output of the voltage control system (AVR) and the power control system (APR). A converter control device characterized by that.   A DC / DC converter and a voltage command are input, a voltage control system (AVR) having a detection voltage of one DC system connected to the DC / DC converter as a feedback value, and a power command are input. The power flow from the DC system to the DC / DC converter is used as a feedback value, and when the detection voltage of the DC system rises above a predetermined value, the power command is increased according to the magnitude of the rise. A power control system (APR) including a voltage maintenance function system, and a control device that controls the DC / DC converter according to the larger output of the voltage control system (AVR) and the power control system (APR) A converter control device characterized by that.   An AC / DC converter, a voltage command, a voltage control system (AVR) that uses a detection voltage on the DC side of the AC / DC converter as a feedback value, a power command, and the AC / DC converter A voltage maintaining function system for setting the power command to the DC side as a feedback value and increasing the power command according to the magnitude of the decrease when the detected voltage on the DC side drops below a predetermined value. And a control device that controls the AC / DC converter according to the smaller output of the voltage control system (AVR) and the power control system (APR). Converter control device. An AC / DC converter and a voltage command are input, and a voltage control system (AVR) using a detection voltage on the DC side of the AC / DC converter as a feedback value, and a power command are input, and the AC / DC converter receives the AC / DC converter from the DC system. Including a voltage maintaining function system that uses the power flow to the DC converter as a feedback value and increases the power command according to the magnitude of the rise when the detected voltage on the DC side rises above a predetermined value A power control system (APR) and a control device that controls the AC / DC converter according to the larger output of the voltage control system (AVR) and the power control system (APR) are provided. Converter control device.

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