JP2015106999A - Power supply facility and operational method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively and effectively utilize a storage battery while preventing an instantaneous power failure regarding a power supply facility and an operational method thereof.SOLUTION: In the power supply facility, power is supplied from a DC bus having capacitance by a capacitor to a load, a bidirectional conversion device is interposed between the DC bus and the storage battery, and a constant voltage power supply device provides power through a diode to the DC bus. When a DC bus voltage becomes equal to or higher than a charging start voltage V, the conversion device starts charging the storage battery and when the DC bus voltage becomes equal to or lower than a discharging start voltage V, the conversion device starts discharging the storage battery. When a voltage of the constant voltage power supply device is defined as V, in a normal mode, a relation of V<V<Vis established in a relative magnitude relation and in a discharge mode a relation of V<V<Vis established in the relative magnitude relation.

Description

  The present invention relates to a power supply facility that supplies power to a load and an operation method thereof.

  For example, for power supply applications used in wireless base stations, a solar power generation device that is not intended for selling power through grid interconnection, a storage battery with high energy density such as a lithium ion battery, and a DC power source based on the system power source A combined power supply facility has been proposed (see, for example, Patent Document 1 (FIGS. 2 and 6 to 8)). Such a power supply facility is useful in that it does not depend only on power purchase from the system power supply.

  The voltage from such a plurality of different power sources is once integrated into the DC bus, and then directly or as necessary converted into a desired voltage to supply power to the load. The storage battery when the photovoltaic power generator is generating power is charged when there is a surplus in the photovoltaic power generation relative to the load power. Further, at night when the solar power generation device does not generate power, power is supplied to the load from a DC power source based on the system power source. In the event of a power failure, power is supplied from the storage battery to the load.

  As described above, the storage battery has a function as a buffer or a backup function that supplies surplus power of the photovoltaic power generation apparatus or supplies emergency power when a DC power supply based on a system power supply fails.

JP 2013-42627 A

  However, simply using a storage battery as a buffer cannot contribute to a peak shift to avoid, for example, the peak of commercial power demand. Moreover, there are few opportunities for a storage battery to actually play an active part only by standing by as a backup. For example, the storage battery can be actively utilized if the power supply from the DC power source based on the system power source to the DC bus is intentionally stopped. However, in this case, when the remaining amount of the storage battery reaches the lower limit value and can no longer be discharged, the power source is switched to the DC power source, but an instantaneous power failure occurs at that time. Furthermore, electric power can be supplied only from either the DC power source based on the system power source or the storage battery for the power consumption of the load. If the power consumption of the load can be supplied from both the DC power source based on the system and the storage battery, the power supplied by the DC power source based on the system can be controlled more finely, which can contribute to the peak shift.

  In view of such conventional problems, an object of the present invention is to realize positive utilization of a storage battery while preventing an instantaneous power failure with respect to a power supply facility and an operation method thereof.

The present invention is a power supply facility for supplying power to a load, comprising: a DC bus having a capacity by a capacitor; a storage battery; a bidirectional converter between the DC bus and the storage battery; and a diode. When the voltage of the DC bus becomes equal to or higher than the charging start voltage V _C , the converter starts charging the storage battery, and the voltage of the DC bus is When the voltage becomes equal to or lower than the discharge start voltage V _D , when the converter starts discharging from the storage battery and the voltage of the constant voltage power supply is V _F , V _D <V _F <V _C A control unit that selectively realizes the normal mode in the relationship of V and the discharge mode in the relationship of V _F <V _D <V _C by controlling at least one of the conversion device and the power supply device, Preparation ing.

In the present invention, power is supplied to a load from a DC bus having a capacity of a capacitor, a bidirectional converter is interposed between the DC bus and the storage battery, and the constant voltage power supply is connected via a diode. in the produced power feeding apparatus to provide power to the DC bus, a method of operating a power feeding apparatus to be executed by the control unit, when the voltage of the DC bus becomes greater than or equal to the charge starting voltage V _C, the conversion device There begins charging the storage battery, the voltage of the DC bus becomes less than the discharge starting voltage V _D, the converter starts to discharge from the storage battery, the voltage of the constant voltage power supply when the V _F, in the normal mode, the relative magnitude _{relationship,} a relationship of _{V D <V F <V C} , in the discharge mode, the relative magnitude _{relationship,} the power feeding apparatus to the relationship _{V F <V} D _{<V C} luck It is a rolling method.

  ADVANTAGE OF THE INVENTION According to this invention, active utilization of a storage battery is realizable, preventing an instantaneous power failure.

It is a connection diagram which shows one Embodiment of electric power feeding equipment. It is a circuit diagram of the converter for storage batteries in FIG. It is a graph which shows the relationship between the voltage of a DC bus, and charging / discharging of a storage battery. It is a graph which shows an example of the time change of the voltage of DC bus, and charging / discharging electric power. It is a graph which shows an example of the time change of the voltage of DC bus, and charging / discharging electric power. It is a graph which shows the relationship between the voltage of a DC bus, and charging / discharging of a storage battery in a positive charge mode. It is a graph which shows an example of the time change of the voltage of DC bus, the input electric power from a constant voltage power supply device, and the charging electric power to a storage battery. It is a graph which shows the change of the voltage of DC bus, and charging / discharging electric power in the state which changes a mode from discharge control to limited discharge control. It is a figure which shows the mode change from discharge mode to active charge mode. It is a connection diagram which shows the 2nd example of the hardware constitutions of electric power feeding equipment. It is a connection diagram which shows the 3rd example of the hardware constitutions of electric power feeding equipment. It is a circuit diagram of the converter (AC / DC converter) in FIG. It is a graph which shows the relationship between the voltage of a DC bus, and charging / discharging of a storage battery. It is a graph which shows the change of the voltage of DC bus, and charging / discharging electric power in the state which changes a mode from discharge control to limited discharge control. It is a figure which shows the structural example of the electric power feeding system containing electric power feeding equipment. It is a graph which shows the change of the electric power used on the 1st as an example.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

(1) This is a power supply facility that supplies power to a load, and includes a DC bus having a capacity of a capacitor, a storage battery, and a bidirectional conversion device interposed between the DC bus and the storage battery, A constant voltage power supply device that supplies power to the DC bus via a diode, and when the DC bus voltage becomes equal to or higher than a charging start voltage V _C , the converter starts charging the storage battery, and the DC bus voltage is When the voltage becomes equal to or lower than the discharge start voltage V _D , when the converter starts discharging from the storage battery and the voltage of the constant voltage power supply is V _F , V _D <V _F <V _C A control unit that selectively realizes the normal mode in the relationship of V and the discharge mode in the relationship of V _F <V _D <V _C by controlling at least one of the conversion device and the constant voltage power supply device; , It has.

In the power supply equipment configured as described above, the relative magnitude relationship regarding the voltage differs between the normal mode and the discharge mode. In order to achieve such a relative magnitude relationship, for example, the discharge start voltage V _D and the charge start voltage V _C in the normal mode may be shifted upward in the discharge mode. Alternatively, the discharge start voltage V _D and the charge start voltage V _C may be left as they are, and the constant voltage in the discharge mode may be set to a value lower than the constant voltage in the normal mode.

In the normal mode, the storage battery is a backup existence of the constant voltage power supply device, and the storage battery is not discharged unless a power failure or the like occurs in the constant voltage power supply device. On the other hand, in the discharge mode, since the constant voltage V _F is lower than the discharge starting voltage V _D, even in a state capable of providing a constant voltage V _F, the discharge of the storage battery is performed, raising the voltage of the DC bus. At this time, since the constant voltage power supply is connected to the DC bus via a diode, when the voltage of the DC bus is higher than the constant voltage V _F is composed of a constant-voltage power supply unit and a state can not power supply to the DC bus . So to speak, and held back the supply of the constant voltage V _F to the DC bus, so that the discharge of the battery is performed. That is, the constant voltage power supply device at this time becomes a backup existence for power feeding to the DC bus by the storage battery.

Therefore, by selecting the discharge mode as necessary without changing the hardware configuration, the storage battery can be used more actively to supply power to the load. Further, even if the remaining amount of the storage battery reaches the lower limit value in the discharge mode, the constant voltage V _F of the constant-voltage power supply device is waiting, there is no instantaneous power failure.

(2) Moreover, in (1), the control unit further determines V _D <V _C <in the relative magnitude relationship between the charge start voltage V _C , the discharge start voltage V _D , and the constant voltage V _F. it may be possible to realize by selecting actively charging mode in a relationship of V _F.
In this case, there is a sufficient margin in the supply capacity of the constant voltage power supply device with respect to the power required for the load, and when there is so-called surplus power, the storage battery can be positively charged with the surplus power. Thereby, it is possible to keep as many states as there are sufficient remaining amounts in the storage battery as much as possible, and to improve the operation efficiency of the storage battery.

(3) Moreover, regarding the power supply equipment of (1) or (2), in the discharge mode, the conversion device may limit a current supplied to the DC bus to a constant value.
In this case, when the power supplied to the load is insufficient from only the storage battery, the voltage of the DC bus is lowered and the power is automatically supplied from the constant voltage power supply device at a constant voltage. That is, by limiting the power supplied from the storage battery to a constant value, it is possible to automatically use the power from the constant voltage power supply device in accordance with the power of the load.

(4) Moreover, in the power supply facility of (2), the control unit may execute the active charging mode when the remaining amount of the storage battery decreases to a predetermined value in the discharging mode.
In this case, overdischarge of the storage battery can be prevented.

(5) Moreover, in the power supply facility according to any one of (1) to (4), when the conversion device sets the voltage threshold value of the DC bus for stopping the discharge of the storage battery as the discharge stop voltage V _S , the charge start The relationship with the voltage V _C is preferably V _C > V _S.
In this case, since the discharge stop timing and the charge start timing are different from each other, the behavior of the converter (discharge / charge) can be stabilized.

(6) Moreover, in any one of the power feeding facilities according to (1) to (5), a power generation device using natural energy may be connected to the DC bus separately from the constant voltage power supply device.
In this case, since the power generation amount of such a power generation device is not stable, the voltage of the DC bus is likely to fluctuate. However, in any mode, the storage battery charges when the surplus power is generated, and the storage battery discharges when it is insufficient. By doing so, it is possible to stably supply power to the load using the storage battery in a timely manner.

(7) Moreover, in the power supply equipment in any one of (1) to (6), for example, it is preferable that the control unit selects and executes the discharge mode according to a time zone of a day or a day of the week. .
In this case, a so-called peak shift can be easily realized if the power is positively supplied from the storage battery during the time of day when the power demand is high and on the day of the week.

(8) On the other hand, from the viewpoint of the method, power is supplied to the load from a DC bus having a capacity of a capacitor, and a bidirectional converter is interposed between the DC bus and the storage battery. , a configured power feeding apparatus operating method to provide power via a diode to the DC bus, the voltage of the DC bus becomes greater than or equal to the charge starting voltage V _C, the conversion device to charge the storage battery started, the voltage of the DC bus becomes less than the discharge starting voltage V _D, the converter starts to discharge from the storage battery, when the voltage of the constant voltage power supply unit and the V _F, in the normal mode, the relative in such magnitude _{relationship,} a relationship of _{V D <V F <V C} , in the discharge mode, the relative magnitude _{relationship,} it is an relationship _{V F <V D <V C} .

In the operation method of the power supply facility as described above, the relative magnitude relationship regarding the voltage differs between the normal mode and the discharge mode. In order to achieve such a relative magnitude relationship, for example, the discharge start voltage V _D and the charge start voltage V _C in the normal mode may be shifted upward in the discharge mode. Alternatively, the discharge start voltage V _D and the charge start voltage V _C may be left as they are, and the constant voltage in the discharge mode may be set to a value lower than the constant voltage in the normal mode.

In the normal mode, the storage battery is a backup existence of the constant voltage power supply device, and the storage battery is not discharged unless a power failure or the like occurs in the constant voltage power supply device. On the other hand, in the discharge mode, since the constant voltage V _F is lower than the discharge starting voltage V _D, even in a state capable of providing a constant voltage V _F, the discharge of the storage battery is performed, raising the voltage of the DC bus. At this time, since the constant voltage power supply is connected to the DC bus via a diode, when the voltage of the DC bus is higher than the constant voltage V _F is composed of a constant-voltage power supply unit and a state can not power supply to the DC bus . So to speak, and held back the supply of the constant voltage V _F to the DC bus, so that the discharge of the battery is performed. That is, the constant voltage power supply device at this time becomes a backup existence for power feeding to the DC bus by the storage battery.

Therefore, by selecting the discharge mode as necessary without changing the hardware configuration, the storage battery can be used more actively to supply power to the load. Further, even if the remaining amount of the storage battery reaches the lower limit value in the discharge mode, the constant voltage V _F of the constant-voltage power supply device is waiting, there is no instantaneous power failure.

[Details of the embodiment]
Hereinafter, the details of the embodiment will be described with reference to the drawings.

<< First example of hardware configuration >>
FIG. 1 is a connection diagram illustrating an embodiment of a power supply facility 100. In the figure, a bidirectional converter (DC / DC converter) 3 is provided between a DC bus 1 and a storage battery 2. Further, the converter (AC / DC converter) 5 from the commercial AC power source 4 supplies a constant voltage V _F, it is possible to further via a diode 6, to supply power to the DC bus 1. The converter 5 performs AC / DC rectification. AC power source 4, converter 5 and the diode 6 constitute a constant-voltage power supply device 7 for providing a constant voltage V _F to the DC bus.

Further, the output of the solar power generation device 8 supplies a voltage to the DC bus 1 via the conversion device 9. The conversion device 9 performs MPPT (Maximum Power Point Tracking) control on the photovoltaic power generation device 8. The voltage of the DC bus 1 is converted into an AC predetermined voltage by the inverter 10, and power is supplied to the load 11.
A capacitor 12 is connected to the DC bus 1 so that the DC bus 1 has a capacitance.

FIG. 2 is a circuit diagram of the conversion device 3 for the storage battery 2 in FIG. Converter 3 includes a conversion unit 31, a voltage sensor 32 for detecting a voltage V _B across the terminals of the battery 2, the current I _B or vice versa and outputs from the battery 2 to the converting unit 31, the storage battery from the conversion unit 31 a current sensor 33 for detecting the current _{I B} to be input to the 2, a voltage sensor 34 for detecting the voltage _{V DC} of DC bus 1, and a control unit 30. The conversion unit 31 includes a capacitor 311, switching elements 312 and 313, a reactor 314, and a capacitor 315 in order from the left side, and are connected as illustrated.

The control unit 30 controls on / off of the switching elements 312 and 313. The detection output information of the voltage sensors 32 and 34 and the current sensor 33 is given to the control unit 30.
When power is sent to the DC bus 1 by discharging the storage battery 2, control as a step-up chopper is performed by PWM control of the switching elements 312 and 313 based on the control of the control unit 30. When the storage battery 2 is charged based on the voltage V _DC of the DC bus 1, the step-down chopper is controlled by PWM control of the switching elements 312 and 313 based on the control of the control unit 30. Note that the control unit 30 may be provided outside rather than as part of the conversion device 3.

  Hereinafter, although operation | movement of the electric power feeding equipment 100 is demonstrated, this is also description about the operating method of the electric power feeding equipment 100. FIG.

《Normal mode / Discharge mode》
FIG. 3 is a graph showing the relationship between the voltage of the DC bus 1 and the charge / discharge of the storage battery 2. In normal mode on the left,
The voltage threshold value of the DC bus 1 for starting the charging of the storage battery 2 (charging above this threshold value) is set as the charging start voltage V _C ,
The voltage threshold of the DC bus 1 that causes the storage device 2 to start discharge by the conversion device 3 (discharge below this threshold) is set as the discharge start voltage V _D ,
The constant voltage provided from the constant voltage power supply device to the DC bus 1 is represented by V _F ,
When the in relative magnitude _{relationship,} a relationship of _{V D <V F <V C} .

The voltage threshold (discharge stop voltage) of the DC bus 1 at which the converter 3 stops discharging the storage battery 2 and the voltage threshold (charge stop voltage) of the DC bus 1 at which charging of the storage battery 2 is stopped are V _{D to} V _C. Although there are various setting methods within the range, the common value is used here, and the charge / discharge stop voltage V _S is used. That is, this is both the charge stop voltage V _S and the discharge stop voltage V _S. Furthermore, it is assumed here that V _S ≈V _F.
Here, since the relationship of V _S <V _C is satisfied, the discharge stop timing and the charge start timing are shifted from each other, so that the behavior (discharge / charge) of the converter 3 can be stabilized. .

In the normal mode, the power generation amount of the photovoltaic power generation device 8 is increased, the surplus power is increased in comparison with the load power, the voltage of the DC bus 1 rises above the constant voltage V _F supplied from the constant-voltage power supply device 7. When the voltage of the DC bus 1 has reached the charging start voltage V _C, converter 3, to charge the battery 2 based on the voltage of the DC bus 1. When the voltage of the DC bus 1 decreases due to charging and becomes a charging / discharging stop voltage V _S (substantially the same as the constant voltage V _F ), charging is stopped. If the relationship between the power generation amount of the solar power generation device 8 and the load power is the same, the voltage of the DC bus 1 again increases thereafter.

In the normal mode, as long as it is supplied with the constant voltage V _F from the constant-voltage power supply device 7, the storage battery 2 is never discharged, if the constant-voltage power supply 7 is a power failure, if the voltage of the DC bus 1 is decreased is there. When the voltage drops to the discharge start voltage V _D , the conversion device 3 discharges the storage battery 2 and provides the voltage to the DC bus 1. As a result, when the voltage of the DC bus 1 increases and reaches the charge / discharge stop voltage V _S (substantially the same as the constant voltage V _F ), the discharge is stopped. After that, if the situation is the same, similarly, the discharge from the storage battery 2 is repeated.

  FIG. 4 is a graph showing an example of the temporal change in the voltage of the DC bus 1 and the charge / discharge power when the output of the solar power generation device 8 is 0, for example. The broken line at the center is the voltage (380 V) of the DC bus 1. The dotted line is the power (2000 W) output from the constant voltage power supply device 7, and the solid line is the power (0 W) output from the storage battery 2. That is, if there is no fluctuation element like solar power generation and the load power is constant, necessary power is stably supplied from the constant voltage power supply device 7, and the storage battery 2 does not contribute to power supply.

Returning to FIG. 3, in the discharge mode on the right side, the control unit 30 shifts the charge start voltage V _C , the charge / discharge stop voltage V _S , and the discharge start voltage V _D upward from the normal mode (changes the threshold value). .) That is, unlike the normal mode, the value of the above in the relative magnitude relation, a relation of _{V F <V D <V C} . _Further, a _{V D <V S <V C} .

When the amount of power generated by the solar power generation device 8 increases and the surplus power increases compared to the load power, the voltage of the DC bus 1 rises above the charge / discharge stop voltage V _S. When the voltage of the DC bus 1 has reached the charging start voltage V _C, converter 3, to charge the battery 2 based on the voltage of the DC bus 1. Voltage of the DC bus 1 is lowered by the charging, at a charge and discharge stop voltage V _S, the charge stop. If the relationship between the power generation amount of the solar power generation device 8 and the load power is the same, the voltage of the DC bus 1 again increases thereafter.

Even if the constant voltage power supply 7 does not fail, when the voltage of the DC bus 1 drops to the discharge start voltage V _D (> V _F ), the converter 3 discharges the storage battery 2 to the DC bus 1. Provides voltage. As a result, when the voltage of the DC bus 1 increases and reaches the charge / discharge stop voltage V _S , the discharge is stopped. After that, if the situation is the same, similarly, the discharge from the storage battery 2 is repeated.

  FIG. 5 is a graph showing an example of the time change of the voltage of the DC bus 1 and the charge / discharge power when the output of the solar power generation device 8 is 0 or small, for example. A broken line in the center is a voltage of the DC bus 1. The dotted line is the electric power (0 W) output from the constant voltage power supply device 7, and the solid line is the electric power output from the storage battery 2 (about 2800 W and 0 W intermittent output with an average of about 2000 W). That is, necessary electric power is supplied from the storage battery 2, and the constant voltage power supply device 7 does not contribute to electric power supply. The voltage of the DC bus 1 fluctuates but is a certain voltage (380V) or more.

As described above, in the normal mode, the storage battery 2 is a backup existence of the constant voltage power supply device 7, and the storage battery 2 is not discharged unless a power failure or the like of the constant voltage power supply device 7 occurs. On the other hand, in the discharge mode, the constant voltage V _F is lower than the discharge start voltage V _D , so that the storage battery 2 is discharged and the voltage of the DC bus 1 is increased even when the constant voltage V _F can be provided. At this time, since the constant-voltage power supply 7 is connected to the DC bus 1 through the diode 6, when the voltage of the DC bus 1 is higher than the constant voltage V _F from the constant-voltage power supply 7 to the DC bus 1 Power supply cannot be performed. So to speak, and held back the supply of the constant voltage V _F to the DC bus 1, so that the discharge of the storage battery 2 is performed. That is, the constant voltage power supply device 7 at this time serves as a backup for power supply to the DC bus 1 by the storage battery 2.

When the discharge of the storage battery 2 progresses, the voltage of the DC bus 1 is decreased, the voltage if below the constant voltage V _F, a constant voltage V _F is supplied from the constant-voltage power supply unit 7 waiting. Therefore, no instantaneous power failure occurs.

In this way, the storage battery 2 can be more actively utilized to supply power to the load 11 by selecting a discharge mode as necessary without changing the hardware configuration of the power supply facility 100. . Further, even if the remaining amount of the storage battery 2 has reached the lower limit value in the discharge mode, the constant voltage V _F of the constant-voltage power supply 7 is waiting, momentary power failure does not occur.

  In addition to the solar power generation device 8, when a power generation device using natural energy including a wind power generation device is connected to the DC bus 1, the power generation amount of the power generation device is not stable. The voltage of is easy to fluctuate. However, in any mode, when the surplus power is generated, the storage battery is charged when surplus, and when the storage power is insufficient, the storage battery is discharged, so that the storage battery 2 can be used to supply power stably to the load in a timely manner. .

《Active charging mode》
Next, an active charge mode that can be set separately from the normal mode and the discharge mode will be described.
FIG. 6 is a graph showing the relationship between the voltage of the DC bus 1 and the charge / discharge of the storage battery 2 in the active charging mode.
In the figure, in the active charge mode, the relative magnitude relationship among the charge start voltage V _C , the discharge start voltage V _D , and the constant voltage V _F is a relationship of V _D <V _C <V _F. Discharge starting voltage _{V S are} in a relationship of _{V D <V S <V C} .

The control unit 30 selects the positive charging mode when the demand power of the load 11 is less than the power supplied by the constant voltage power supply device 7. In this case, in view of the supply power of the constant voltage power supply device 7, there is so-called surplus power. When actively charge mode is selected in this state, the voltage of the DC bus 1, because it is the charging start voltage V _C or more, the control unit 30 operates the converter 3 so as to charge the battery 2. Of course, at the time of a power failure of the constant voltage power supply device 7, backup by the storage battery 2 is performed.

  FIG. 7 is a graph showing an example of the time change of the voltage of the DC bus 1, the input power from the constant voltage power supply device 7, and the charging power to the storage battery 2. The surplus power of the constant voltage power supply device 7 is used for charging the storage battery 2. The voltage of the DC bus (380V) is stable.

  As described above, when there is a sufficient margin in the supply capability of the constant voltage power supply device 7 with respect to the power required for the load 11 and there is surplus power, the positive charge mode is selected so that the surplus power is positive. The storage battery 2 can be charged. Thereby, the state with sufficient remaining amount in the storage battery 2 can be kept as much as possible, and the operation efficiency of the storage battery 2 can be improved.

《Limited discharge mode》
For example, consider the case where the storage battery 2 is discharged in the discharge mode of FIG. In this case, if the storage battery 2 alone cannot provide all the power required for the load 11 or if the burden is large, the constant voltage power supply device 7 needs to be assisted. Therefore, the discharge current of the storage battery 2 may be limited so that such a situation can be realized. The restriction of the discharge current can be easily realized by the control unit 30 setting the current value in the constant current control of the converter 3 to a constant value and limiting the constant value to the constant value.

  FIG. 8 is a graph showing changes in the voltage of the DC bus 1 and charge / discharge power in a state where the mode is changed from the discharge control to the limited discharge control. The converter 3 discharges the storage battery 2 until the time t is 0 to t1. After time t1, the discharge current of the storage battery 2 is limited to a constant current. As a result, when the voltage of the DC bus 1 decreases and reaches about 380 V, necessary power is supplied from the constant voltage power supply device 7 which has been 0 W until then.

Thus, the power is supplied by the DC voltage of the bus 1 is decreased automatically constant voltage from the constant-voltage power supply 7 (V _F) when the power supplied to the load 11 is insufficient only from the storage battery 2 . That is, by limiting the power supplied from the storage battery 2 to a constant value, the power from the constant voltage power supply device 7 can be automatically used in accordance with the power of the load 11. By appropriately selecting a constant value, it is possible to determine the share of power supply between the storage battery 2 and the constant voltage power supply device 7. In this case, the voltage of the limited DC bus 1 is stable. The calculation for determining the burden ratio is relatively easy.

《Discharge mode to active charge mode》
FIG. 9 is a diagram showing a mode change from the discharge mode to the active charge mode. In the left discharge mode of FIG. 9, when the remaining amount of the storage battery 2 is reduced to a predetermined value, the control unit 30 changes the control of the conversion device 3 to the positive discharge mode shown on the right side. The remaining amount of the storage battery 2 can be grasped by integrating the voltage V _B detected by the voltage sensor 32 (FIG. 2) or the current I _B detected by the current sensor 33 (FIG. 2).
In the active charge mode, the control unit 30 shifts the charge start voltage V _C , the charge / discharge stop voltage V _S , and the discharge start voltage V _D downward (changes the threshold value) below the discharge mode. That is, in the relative magnitude relationship, each value has a relationship of V _D <V _S <V _C <V _F. Thereby, the storage battery 2 can be charged.

<< Second example of hardware configuration >>
FIG. 10 is a connection diagram illustrating a second example of the hardware configuration of the power supply facility 100. The difference from FIG. 1 is that the constant voltage power supply device 7 is a DC power supply, and the load 11 is also a DC load, and the other configurations are the same. Also in this case, each of the above modes can be applied to the control unit of the conversion device 3 just as in the first example.

<< Third example of hardware configuration >>
FIG. 11 is a connection diagram illustrating a third example of the hardware configuration of the power supply facility 100. The difference from FIG. 1 is that the constant voltage power supply device 7 is a DC power supply, and the load 11 is also a DC load. Further, this configuration does not have a solar power generation device, and is the simplest configuration of a DC power supply facility. Also in this case, each of the above modes can be applied to the control unit of the conversion device 3 just as in the first example.

<Normal mode / discharge mode, etc. controlled by the constant voltage power supply>
In each of the above modes, the control unit 30 of the conversion device 3 changes the threshold value of the operation of the conversion device 3 with respect to the voltage of the DC bus 1.
However, the same relative change can also be realized by changing the constant voltage V _F of the constant voltage power supply device 7 (V _FH or V _FL ) without changing the operation threshold of the conversion device 3.

FIG. 12 is a circuit diagram of the converter (AC / DC converter) 5 in FIG. The converter 5 includes a synchronous rectifier circuit 51, a voltage sensor 52 that detects an _AC voltage VAC, a current sensor 53 that detects an input current I _AC , a voltage sensor 54 that detects a voltage V _DC of the DC bus 1, And a control unit 50.

The control unit 50 controls on / off of a switching element (not shown) in the synchronous rectifier circuit 51 and also controls the output voltage. The detection output information of the voltage sensors 52 and 54 and the current sensor 53 is given to the control unit 50.
Note that the control unit 50 may be provided outside rather than as part of the conversion device 5.

FIG. 13 is a graph showing the relationship between the voltage of the DC bus 1 and the charge / discharge of the storage battery 2. First, in the normal mode on the left,
The voltage threshold value of the DC bus 1 for starting the charging of the storage battery 2 is set as the charging start voltage V _C ,
The voltage threshold value of the DC bus 1 that causes the converter 3 to start discharging the storage battery 2 is set as the discharge start voltage V _D ,
The constant voltage provided from the constant voltage power supply device to the DC bus 1 is expressed as V _FH ,
When the in relative magnitude _{relationship,} a relationship of _{V D <V FH <V C} . The charge / discharge stop voltage V _S can be set in various ways within the range of V _{D to} V _C , but here, V _S ≈V _FH .

In the normal mode, when the power generation amount of the solar power generation device 8 increases and surplus power increases compared to the load power, the voltage of the DC bus 1 rises above the constant voltage _VFH provided from the constant voltage power supply device 7. When the voltage of the DC bus 1 has reached the charging start voltage V _C, converter 3, to charge the battery 2 based on the voltage of the DC bus 1. When the voltage of the DC bus 1 decreases due to charging and reaches a charge / discharge stop voltage V _S (substantially the same as the constant voltage V _FH ), the charge is stopped. If the relationship between the power generation amount of the solar power generation device 8 and the load power is the same, the voltage of the DC bus 1 again increases thereafter.

As long as the constant voltage _VFH is supplied from the constant voltage power supply device 7, the storage battery 2 is not discharged. However, when the constant voltage power supply device 7 fails, the voltage of the DC bus 1 may decrease. When the voltage drops to the discharge start voltage V _D , the conversion device 3 discharges the storage battery 2 and provides the voltage to the DC bus 1. As a result, when the voltage of the DC bus 1 increases and reaches the charge / discharge stop voltage V _S (substantially the same as the constant voltage V _FH ), the discharge is stopped. After that, if the situation is the same, similarly, the discharge from the storage battery 2 is repeated.

On the other hand, in the discharge mode on the right side, the control unit 50 of the conversion device 5 reduces the value of the constant voltage V _FH to another constant voltage V _FL . As a result, unlike the normal mode, the value of the above in the relative magnitude _{relationship,} a relationship of _{V FL <V D <V C} . _Further, a _{V D <V S <V C} .

In the discharge mode, when the amount of power generated by the solar power generation device 8 increases and the surplus power increases compared to the load power, the voltage of the DC bus 1 rises above the charge / discharge stop voltage V _S. When the voltage of the DC bus 1 has reached the charging start voltage V _C, converter 3, to charge the battery 2 based on the voltage of the DC bus 1. Voltage of the DC bus 1 is lowered by the charging, at a charge and discharge stop voltage V _S, the charge stop. If the relationship between the power generation amount of the solar power generation device 8 and the load power is the same, the voltage of the DC bus 1 again increases thereafter.

Even if the constant voltage power supply 7 does not fail, when the voltage of the DC bus 1 drops to the discharge start voltage V _D (> V _FL ), the converter 3 discharges the storage battery 2 to the DC bus 1. Provides voltage. As a result, when the voltage of the DC bus 1 increases and reaches the charge / discharge stop voltage V _S , the discharge is stopped. After that, if the situation is the same, similarly, the discharge from the storage battery 2 is repeated.

Thus, even if the constant voltage V _F is changed to V _FH or V _FL using the control unit 50 on the constant voltage power supply device 7 side, the same thing as shifting the operation threshold as shown in FIG. And similar effects can be obtained.
That is, the discharge start voltage V _D and the charge start voltage V _C in the normal mode are shifted in the discharge mode, or the constant voltage in the discharge mode is maintained while the discharge start voltage V _D and the charge start voltage V _C remain unchanged. The voltage may be changed from the constant voltage in the normal mode. These can also be used in combination. The same applies to other various modes.

It should be noted that the same applies to the limited discharge mode of the storage battery 2 by limiting the output current of the converter 5. In this case, it is output from the constant voltage power supply device 7 rather than limiting the output of the storage battery 2, but by limiting the output, it also means that the output is also borne by the storage battery 2 to some extent.
FIG. 14 is a graph showing changes in the voltage of the DC bus 1 and charge / discharge power in a state where the mode is changed from the discharge control to the limited discharge control. From time t to 0 to t1, electric power is supplied from the constant voltage power supply device 7 to the load 11, and no electric power is output from the storage battery 2. When the output from the constant voltage power supply device 7 is limited at time t1, the output is also provided from the storage battery 2 to the load 11.

  In this way, power supply using the constant voltage power supply device 7 and the storage battery 2 in combination is possible. However, as compared with the control shown in FIG. 8, there are some difficulties that the voltage of the DC bus 1 fluctuates and the calculation of the burden ratio becomes complicated.

《Example of practical system》
FIG. 15 is a diagram illustrating a configuration example of a power feeding system including the power feeding facility 100. As illustrated in FIG. 1, the power supply facility 100 includes, for example, a DC bus 1, a storage battery 2, a bidirectional converter 3, an AC power supply 4, a converter 5, a solar power generator 8, a converter 9, and an inverter 10. The load 11 is provided. The four converters 3, 5, 9, 10 can also be configured as one multi-power conditioner 101. The control unit for switching the mode can be incorporated in the conversion device 3 or 5, for example, or can be provided independently in the multi-power conditioner 101. Furthermore, another power generator may be connected to the DC bus 1 as the expansion unit 102. For example, power can be sent to the DC bus 1 from the solar power generation device 21 via the conversion device 23 or from the wind power generation device 22 via the conversion device 24, respectively.

《Peak shift》
The above power supply equipment can cope with the peak shift by changing the mode. For example, in the case of a consumer whose daily power consumption changes as shown in FIG. 16, the target power for saving is set according to the time zone or day of the week when the power demand is expected to increase. And, if the power of the storage battery is positively utilized during the time period exceeding the target power and the power lost by the storage battery is charged using, for example, night power, it can easily cope with the peak shift. .

<Others>
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 DC bus 2 Storage battery 3 Converter 4 AC power supply 5 Converter 6 Diode 7 Constant voltage power supply 8 Solar power generator 9 Converter 10 Inverter 11 Load 12 Capacitor 21 Solar power generator 22 Wind generator 23, 24 Converter 30 Control unit 31 Conversion unit 32 Voltage sensor 33 Current sensor 34 Voltage sensor 50 Control unit 51 Synchronous rectifier circuit 52 Voltage sensor 53 Current sensor 54 Voltage sensor 100 Power supply facility 101 Multi-power conditioner 102 Expansion unit 311 Capacitors 312 and 313 Switching element 314 Reactor 315 capacitor

Claims (8)

A power supply facility for supplying power to a load,
A DC bus with a capacitor capacity;
A storage battery,
A bidirectional converter interposed between the DC bus and the storage battery;
A constant voltage power supply that provides power to the DC bus via a diode;
When the voltage of the DC bus becomes equal to or higher than the charging start voltage V _C , the converter starts charging the storage battery, and when the DC bus voltage becomes equal to or lower than the discharge start voltage V _D , the converter discharges from the storage battery. started, when the voltage of the constant voltage power supply unit and the _{V F,} the relative magnitude _{relationship,} the normal mode is in the relation of _{V D <V F <V C} , _and, V _{F <V} D _{<of V C} A controller that selectively realizes a discharge mode in a relationship by controlling at least one of the converter and the constant voltage power supply; and
Power supply equipment equipped with. Wherein the control unit, the charge start voltage _{V C,} the discharge starting voltage _{V D,} the relative magnitude relationship between the constant voltage _{V F, further,} the positive charge mode in the relation of _{V D <V} C _{<V F} The power supply facility according to claim 1, which can be selected and realized.   3. The power supply facility according to claim 1, wherein, in the discharge mode, the conversion device limits a current supplied to the DC bus to a constant value. 4.   The power supply facility according to claim 2, wherein the control unit executes the active charging mode when a remaining amount of the storage battery is reduced to a predetermined value in the discharging mode. The relationship between the charging start voltage V _C and V _C > V _S when the voltage threshold value of the DC bus that causes the converter to stop discharging the storage battery is the discharge stop voltage V _S. Item 5. The power supply facility according to any one of Items 4 to 4.   The power supply facility according to any one of claims 1 to 5, wherein a power generation device using natural energy is connected to the DC bus separately from the constant voltage power supply device.   The power supply facility according to any one of claims 1 to 6, wherein the control unit selects and executes the discharge mode according to time. Power is supplied to a load from a DC bus having a capacity of a capacitor, a bidirectional converter is interposed between the DC bus and the storage battery, and the constant voltage power supply device supplies power to the DC bus via a diode. A method of operating a power supply facility configured to provide,
When the voltage of the DC bus becomes greater than or equal to the charge starting voltage V _C, the conversion device starts to charge the battery, the voltage of the DC bus becomes less than the discharge starting voltage V _D, discharge the converter from the battery It was started, the voltage of the constant voltage power supply when the V _F,
In the normal mode, the relation of V _D <V _F <V _C is assumed in the relative magnitude relationship,
In discharge mode, the relative magnitude _{relationship,} a relationship of _{V F <V D <V C} ,
Operation method of power supply equipment.

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