JP2016100993A - Photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power generation system that adopts a low-cost lead accumulator battery, and that can elongate the life of the accumulator battery, and that can enhance the utilization efficiency of solar energy.SOLUTION: A photovoltaic power generation system comprises: a first charger 4 that charges a power storage device 7 by an output of a solar battery panel 2; a second charger 5 that charges the power storage device 7 by external power supplies 60 and 61; a detector 12 that detects a residual capacity of the power storage device 7; and an inverter 15 that converts a power stored in the power storage device 7 and supplies to a load side circuit. The power storage device 7 comprises three or more systems configured by lead accumulator batteries 11. The photovoltaic power generation system comprises switching means 20 that connects one system selected from the systems with an output side circuit of the first charger 4 or the second charger 5, connects another system with an input side circuit of the inverter 15, and further connects the other system with the detector 12. Thereby, overdischarge is suppressed to suppress generation of sulfation by adopting the low-cost lead accumulator battery 11, and thus, the life can be elongated.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a solar power generation system, and particularly to a solar power generation system including a power storage device.

  Conventionally, a solar power generation system disclosed in Patent Document 1 is known as this type of solar power generation system. The solar power generation system described in this document includes a storage battery that is charged by electric power generated by a solar cell device or electric power from an electric power system. And in the time slot | zone with high electric power demand, in addition to the electric power generation amount from a solar cell apparatus, the electric power stored in the storage battery is discharged and supplied to an inverter. This document describes that a nickel / hydrogen storage battery, a nickel / cadmium storage battery, or a lithium ion battery is suitable as the storage battery to be used.

  As another example of the prior art, a battery state detection device for a solar power generation battery system disclosed in Patent Document 2 is known. The apparatus of the literature includes an auxiliary battery (lithium ion battery) connected to a solar cell panel via a power converter, and a lead battery connected to the auxiliary battery via a bidirectional power converter. Yes.

Japanese Unexamined Patent Publication No. 2003-79054 (page 4-5, FIG. 1) JP 2012-186877 A (page 10-11, FIG. 1)

  However, as in the prior art disclosed in Patent Document 1, a system that employs a lithium ion battery or the like as a storage battery has a problem that the cost of the storage battery is high.

  Moreover, like the prior art disclosed by patent document 2, when employ | adopting a lead storage battery, there exists a problem that the lifetime of a storage battery is short. Specifically, when a lead storage battery is used for a long period of time, the charge capacity is remarkably reduced due to a so-called sulfation phenomenon in which lead sulfate crystals adhere to the surface of the electrode and impede energization.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to adopt an inexpensive lead storage battery, to extend the life of the storage battery, and to use solar energy efficiently. It is to provide a solar power generation system that can increase the power consumption.

  The solar power generation system of the present invention includes a first charger that charges the power storage device with an output of the solar battery panel, a second charger that charges the power storage device with an external power source, and a remaining capacity of the power storage device. A detector for detecting, and an inverter for converting electric power stored in the power storage device and supplying the converted power to a load side circuit, the power storage device having three or more series composed of lead acid batteries, One series selected from the series is connected to the output side circuit of the first charger or the second charger, the other series is connected to the input side circuit of the inverter, and another series is connected An opening / closing means connected to the detector is provided.

  According to the solar power generation system of the present invention, the power storage device that stores the power generated by the solar battery panel has three or more series of lead storage batteries. Then, by switching the opening / closing means, one series selected from the series is connected to the output side circuit of the first charger or the second charger, and the other series is connected to the input side circuit of the inverter. Further, another series is connected to a detector that detects the remaining capacity of the power storage device.

  Thereby, while charging one storage battery constituting the power storage device, power is supplied from the other storage battery to the load side circuit (inverter, etc.), and the remaining capacity of the other storage battery is further reduced. Can be detected. That is, the photovoltaic power generation system of the present invention can accurately grasp the remaining capacity of the power storage device without interrupting charging by photovoltaic power generation or power feeding to the load side circuit. As a result, since the charge / discharge status of the storage battery can be easily managed, the overdischarge of the storage battery can be suppressed to suppress the occurrence of sulfation, and the life of the storage battery can be extended.

  In addition, since the charging of the power storage device is not interrupted when detecting the remaining capacity of the storage battery, solar energy can be effectively used without interrupting solar power generation in a state where a sufficient amount of solar radiation is obtained. .

  In addition, an inexpensive lead storage battery can be adopted as the storage battery, and since the deterioration of the storage battery can be suppressed and the life can be extended, the initial cost of the system and the maintenance cost such as replacement of the storage battery can be greatly reduced. Can do.

  Further, by switching the opening / closing means, each series of power storage devices may be connected to a detector in order to detect the remaining capacity for each series. Thereby, since the remaining capacity of each series can be detected by one detector without providing a plurality of detectors, the cost of the system can be reduced.

  Further, based on the remaining capacity of each series detected by the detector, the storage battery of the series having the smallest remaining capacity may be connected to the first charger or the second charger. As a result, it is possible to preferentially charge a series with a small remaining capacity, so that overdischarge of the storage battery is suppressed and occurrence of sulfation is suppressed. As a result, a sufficient storage / discharge capacity can be maintained over a long period of time.

  Moreover, since storage batteries of a series having a small remaining capacity can be preferentially charged, the use efficiency of solar energy can be improved in a state where a sufficient amount of solar radiation is obtained. That is, since the electric power generated by the solar cell panel can be stored in a series of storage batteries having a large capacity that can be stored, a suitable power generation state can be maintained without reducing the power generation amount of the solar cell panel.

  Alternatively, a pulse oscillator that is connected to the power storage device and generates a pulse voltage may be provided. Then, by switching the opening / closing means, one series of power storage devices is connected to the output side circuit of the first charger or the second charger, the other series is connected to the input side circuit of the inverter, and the other May be connected to a pulse oscillator.

  Thus, while charging one series of storage batteries constituting the power storage device, power is supplied from the other series of storage batteries to the load side circuit, and a pulse voltage is applied to the other series of storage batteries. Occurrence of sulfation can be suppressed. That is, without interrupting charging by solar power generation or power feeding to the load side circuit, it is possible to prevent or remove sulfation by connecting a storage battery of a series that is not charged or discharged to a pulse oscillator. Thereby, deterioration of a storage battery can be prevented and the lifetime improvement can be achieved further.

  Further, the series may be connected to the output side circuit of the second charger that uses the external power source only when the remaining capacity of at least one series of the power storage device becomes smaller than a predetermined value. As a result, charging with an external power source is performed only when the remaining capacity falls below a predetermined reference value, so as to ensure the storage capacity for solar power generation while minimizing the use of external power, Overdischarge of the storage battery can be suppressed.

  Moreover, you may provide the output switch which selects any one of the output side circuit of an inverter, and an external power supply, and connects to a load side circuit. Then, when the remaining capacity of all series constituting the power storage device becomes smaller than a predetermined value, the output switch and the load circuit are shut off by switching the output switch. A power supply and a load side circuit may be connected.

  As a result, when the remaining capacity of the power storage device falls below a predetermined reference value, the discharge of the storage battery can be stopped to prevent overdischarge, so that the occurrence of sulfation can be suppressed and deterioration of the storage battery can be prevented. Further, even when the remaining capacity of the power storage device is reduced and the discharge is stopped, it is possible to supply power to the load side circuit using the external power source. Thereby, stable power supply is possible.

  Also, multiple power storage devices are provided, the load side circuit is divided into multiple systems, load detectors are provided to detect the power load of each system, and the output side circuit of the power storage device is alternatively connected to each system A switching device may be provided. Then, the switching device may be switched based on the remaining capacity of each power storage device detected by the detector and the power load of each system detected by the load detector. Specifically, power storage devices with a large remaining capacity are connected in order from a system with a large power load.

  As a result, it is possible to build a large-capacity power storage device using an inexpensive lead storage battery, and even in this case, while suppressing the overdischarge of the power storage device and extending the life of the storage battery, high efficiency With this, stable power supply can be performed.

It is a block diagram which shows schematic structure of the solar energy power generation system which concerns on embodiment of this invention. It is a block diagram showing the outline of the wiring system same as the above. It is a flowchart which shows charge / discharge control same as the above. It is a figure which shows operation | movement of a battery remaining charge detection same as the above. It is a figure which shows an example of the switching pattern of a switch same as the above. It is a flowchart which shows power supply selection control same as the above. It is a flowchart which shows switching control of the output switch same as the above. It is a figure which shows operation | movement of a battery remaining charge detection same as the above. It is a block diagram which shows the outline of the solar energy power generation system which concerns on other embodiment of this invention. It is a block diagram showing the wiring system of the switching apparatus same as the above. It is a figure which shows an example of the switching pattern of a switching apparatus same as the above.

Hereinafter, a photovoltaic power generation system according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of the photovoltaic power generation system 1. As shown in FIG. 1, the photovoltaic power generation system 1 includes a solar cell panel 2, a battery module 3 that stores electric power generated by the solar cell panel 2, and an inverter 15.

  The battery module 3 is a device that controls the power generation by the solar battery panel 2 and stores the generated power and supplies it to the inverter 15. The battery module 3 includes a solar charger 4 as a first charger, a pulse charger 5 as a second charger, a pulse oscillator 6, a detector 12, and a charge / discharge switching device as an opening / closing means. 20 and a power storage device 7 including a battery 11 which is a lead storage battery.

  The solar battery charger 4 is connected to the solar battery panel 2 and suitably controls power generation of the solar battery panel 2 by executing, for example, maximum power point tracking control (MPPT: Maximum Power Point Tracking). Then, the solar battery charger 4 converts the electric power generated by the solar battery panel 2 and charges the battery 11 of the power storage device 7. Note that the solar charger 4 may have a function of adding a pulse voltage of 4000 to 7000 Hz to the output. Thereby, generation | occurrence | production of the sulfation in the battery 11 can be suppressed.

  The pulse charger 5 is connected to external power sources 60 and 61 such as a commercial power source, for example, and charges the battery 11 of the power storage device 7 with the external power sources 60 and 61. Note that the pulse charger 5 has a function of adding a pulsed voltage of 4000 to 7000 Hz to the output, thereby suppressing the occurrence of sulfation in the battery 11.

  The pulse oscillator 6 generates a pulse voltage and is connected to the power storage device 7 via the charge / discharge switching device 20. Specifically, the pulse oscillator 6 operates with the power of the battery 11, generates a pulsed voltage of 4000 to 7000 Hz that is negative with respect to the voltage of the battery 11, and applies it to the battery 11. Thereby, generation | occurrence | production of sulfation can be suppressed with respect to the battery 11, or removal of sulfation (removal of the lead sulfate adhering to an electrode) can be performed. In addition, when the solar charger 4 is provided with the function which outputs a pulse-shaped voltage, the system structure which abbreviate | omitted the pulse transmitter 6 is also possible.

  The detector 12 detects the remaining capacity of the power storage device 7 and is connected to the battery 11 of the power storage device 7 via the charge / discharge switching device 20. Specifically, the detector 12 detects the voltage of the battery 11, converts it into a digital signal, and outputs it to a control device 17 (see FIG. 2) described later. The remaining capacity of the battery 11 can be obtained from the correlation between the voltage and the remaining capacity.

  The power storage device 7 is a device that stores electric power generated by the solar battery panel 2, and includes a battery 11 that is composed of a lead storage battery and divided into a plurality of series. The battery 11 is selectively connected to the solar battery charger 4, the pulse charger 5, the pulse oscillator 6, the detector 12, and the inverter 15 through the charge / discharge switching device 20.

  The inverter 15 is a device that converts electric power stored in the battery 11 of the power storage device 7 into AC power and supplies it to the load side circuit, and is connected to the output side of the battery module 3. An output switch 30 is provided on the output side of the inverter 15 to select any one of the output side circuit of the inverter 15 and the external power source 60 and connect it to the load side circuit.

  FIG. 2 is a configuration diagram illustrating an outline of the wiring system of the photovoltaic power generation system 1. As shown in FIG. 2, the battery 11 of the power storage device 7 is divided into three series (battery 11a, battery 11b, and battery 11c). The power storage device 7 preferably has at least three series, but the power storage apparatus 7 may be provided with four or more series.

  Three switches 23, 24, 25 constituting the charge / discharge switching device 20 are connected to each series of batteries 11. The switch 23 is a charging switch that connects the battery 11 to a circuit on the charging side (a circuit on the output side of the solar charger 4 or the pulse charger 5). The switch 24 is a discharging switch that connects the battery 11 to a load circuit (an input circuit of the inverter 15). The switch 25 is a switch for inspection and sulfation suppression that connects the battery 11 to a circuit on the pulse oscillator 6 or detector 12 side.

  Here, the switch 23, the switch 24, and the switch 25 connected to one system are alternatively closed. For example, only one of the switch 23a, the switch 24a, and the switch 25a connected to the battery 11a is selected and closed. In other words, one series of batteries 11 is connected to any one circuit selected from a charge side circuit, a load side circuit, and a detector 12 side circuit.

  In addition, the charging switch 23 is closed only for one battery 11. That is, the switch 23a, the switch 23b, and the switch 23c are alternatively closed. For example, when the switch 23a is closed, the switch 23b and the switch 23c are blocked. Similarly, the discharge switch 24a, the switch 24b, and the switch 24c are alternatively closed. In addition, the switch 25a, the switch 25b, and the switch 25c for inspection and suppression of sulfation are alternatively closed in the same manner.

  That is, the battery 11 (for example, the battery 11a) of one series selected from the plurality of series by the charge / discharge switching device 20 is connected to the circuit on the output side of the solar charger 4 or the pulse charger 5, and others. The battery 11 (for example, the battery 11b) of this series is connected to the circuit on the input side of the inverter 15, and the battery 11 (for example, the battery 11c) of another series is connected to the detector 12 or the pulse oscillator 6. .

  A switch 21 is interposed in a circuit on the charging side that connects the output side of the solar charger 4 and the switches 23 of each series. In addition, a switch 22 is interposed in a circuit on the charging side that connects the pulse charger 5 and the switches 23 of each series. The switch 21 and the switch 22 are alternatively closed. That is, when the switch 21 is closed, the switch 22 is opened, and when the switch 22 is closed, the switch 21 is opened.

  An external power source 60 is connected to the input side of the pulse charger 5 via the switch 27, and an external power source 61 is connected via the switch 28. The external power source 60 is a commercial power source supplied for home use, for example, and the external power source 61 is a commercial power source based on a nighttime power contract. The switch 27 and the switch 28 are configured to be alternatively closed, whereby normal power from the external power supply 60 or night power from the external power supply 61 is supplied to the pulse charger 5.

  The output switch 30 provided on the output side of the inverter 15 includes a switch 31 that connects the output side of the inverter 15 and the load side circuit, and a switch 32 that connects the external power supply 60 and the load side circuit. Have. The switch 31 and the switch 32 are configured to be alternatively closed, whereby one of the power supplied from the battery module 3 and the power supplied from the external power supply 60 is supplied to the load side circuit. The

  The circuit for inspection and sulfation suppression connected to the switch 25 is provided with a switch 26 that connects the battery 11 to either the detector 12 or the pulse oscillator 6.

  The battery module 3 includes a power generation amount detector 13 that detects a power generation state by the solar cell panel 2. The power generation amount detector 13 detects, for example, the output voltage of the solar cell panel 2, converts it into a digital signal, and outputs it to the control device 17. In addition, you may detect the electric power generation state of the solar cell panel 2 using a solar radiation amount sensor etc. as the electric power generation amount detector 13. FIG.

  The control device 17 is a device that performs charge / discharge control of the battery module 3. Specifically, the control device 17 performs a predetermined calculation based on the remaining capacity of the battery 11 detected by the detector 12 and the power generation state detected by the power generation amount detector 13, and the switches 21 to 25, 27, 28, 31 and 32, and switching of the switch 26 is controlled.

Next, the control operation of the photovoltaic power generation system 1 shown in FIG. 2 will be described in detail with reference to FIGS.
First, the overall flow of charge / discharge control will be described with reference to FIGS. 2 and 3. FIG. 3 is a flowchart showing charge / discharge control of the photovoltaic power generation system 1.

As shown in FIGS. 2 and 3, when the operation of the system is started (S0), the control device 17 detects the remaining capacity of the battery 11 of the power storage device 7 (S10). Here, the remaining capacity is detected for each of a plurality of series provided.
Next, the control device 17 determines a combination of charge and discharge based on the detected remaining capacity of the battery 11 for each series, and opens and closes the switches 23 to 25 (S20).

  And the control apparatus 17 selects the suitable power supply for charging the battery 11 according to the remaining capacity of the battery 11, and the electric power generation condition of the solar cell panel 2, and switches the switches 21, 22, 27, and 28 ( S30).

  Further, the control device 17 determines whether or not to discharge the battery 11 based on the remaining capacity of the battery 11, and switches the switches 31 and 32 for supplying power to the load side circuit (S50).

  Next, the control device 17 detects again the remaining capacity of the battery 11 for each system of the power storage device 7 (S60). In addition, in order to prevent the switching operation of the switches 21 to 25, 27, 28, 31, 32 and the switching operation of the switch 26 from being frequently performed, an appropriate waiting time (in a control operation for detecting the remaining capacity ( (Delay time) may be provided. For example, the remaining capacity of the battery 11 is detected every 10 minutes, and step S60 may be skipped until 10 minutes have passed.

  If there is no system abnormality or the like and there is no stop instruction or the like by the user (YES in S80), the control device 17 repeatedly executes the control operations in S20 to S60. Thereby, the power generation by the solar cell panel 2, the generated power and charging of the power storage device 7 by the external power sources 60 and 61, and the stable power supply by the power stored in the power storage device 7 and the external power source 60 are performed. .

Next, steps S10 to S60 shown in FIG. 3 will be described in detail.
FIG. 4 is a diagram showing an operation of detecting the remaining capacity of the battery 11 of the solar power generation system 1, and shows details of step S10 in FIG.

2 and 4, the control device 17 switches the switch 26 to the detector 12 side, and sequentially switches the switches 23 to 25 in the order shown in FIG. 4 (S11 to S17).
That is, the control device 17 closes the switch 25a connected to the battery 11a from the state where all the switches 23 to 25 are opened (S11) (S12). Thereby, the battery 11a is connected to the detector 12, and the remaining capacity (voltage) of the battery 11a is detected.

  Next, after interrupting the switch 25a (S13), the control device 17 closes the switch 25b connected to the battery 11b (S14). Thereby, the battery 11b is connected to the detector 12, and the remaining capacity (voltage) of the battery 11b is detected.

  Next, the control device 17 shuts off the switch 25b (S15), and then closes the switch 25c connected to the battery 11c (S16). Thereby, the battery 11c is connected to the detector 12, and the remaining capacity (voltage) of the battery 11c is detected. And the control apparatus 17 interrupts | blocks the switch 25c (S17).

  In this way, by switching the switches 23 to 25 of the charge / discharge switching device 20, each series (batteries 11 a, 11 b, 11 c) of the power storage device 7 is sequentially connected to the detector 12 to detect the remaining capacity for each series. can do.

Thereby, since the remaining capacity of each series can be detected by one detector 12 without providing a plurality of detectors 12, the cost of the system can be reduced.
The control device 17 switches the switch 26 to the pulse oscillator 6 side after detecting the remaining capacity of the battery 11.

  FIG. 5 is a diagram illustrating an example of a switching pattern of the switches 23 to 25 of the solar power generation system 1 in step S20 illustrated in FIG. FIG. 5 shows an example in which the battery 11a has the largest remaining capacity, the battery 11b has the largest remaining capacity, and the battery 11c has the smallest remaining capacity.

As shown in FIGS. 2 and 5, the control device 17 determines a combination of charge and discharge based on the detected remaining capacity of the battery 11 for each series, and opens and closes the switches 23 to 25.
Specifically, the battery 11c of the series having the smallest remaining capacity is connected to the solar charger 4 or the pulse charger 5 for charging. That is, the control device 17 selectively closes the charging switch 23c connected to the battery 11c of the series having the smallest remaining capacity.

  By preferentially charging a series with a small remaining capacity in this way, overdischarge of the battery 11 can be suppressed and occurrence of sulfation can be suppressed. As a result, a sufficient storage / discharge capacity can be maintained over a long period of time.

  In addition, by preferentially charging the battery 11 of a series having a small remaining capacity, it is possible to improve the utilization efficiency of solar energy in a state where a sufficient amount of solar radiation is obtained. That is, since the electric power generated by the solar cell panel 2 can be stored in the battery 11 having a large capacity that can be stored, it is possible to maintain a suitable power generation state without reducing the power generation amount of the solar cell panel 2. Can do.

  On the other hand, the control device 17 discharges the battery 11a of the series having the largest remaining capacity by connecting it to the load side circuit. That is, the control device 17 selects and closes the discharge switch 24a connected to the battery 11a of the series having the largest remaining capacity.

  Then, the remaining series of batteries 11b that are not charged and discharged are connected to the pulse oscillator 6 to apply a pulse voltage. That is, the control device 17 closes the switch 25b for the battery 11b of the series in which both the switch 23b and the switch 24b are cut off. In addition, when there are four or more battery 11 series and there are a plurality of series of batteries 11 that are not charged or discharged, the switches 25 are sequentially arranged for the remaining series that are not charged or discharged. It may be opened and closed.

  In this way, while charging one battery 11c constituting the power storage device 7, power is supplied from the other battery 11a to the load side circuit, and the other battery 11b is pulsed. Generation of sulfation can be suppressed by applying a voltage.

  That is, it is possible to prevent or remove sulfation by connecting the battery 11 of a series that is not charged or discharged to the pulse oscillator 6 without interrupting charging by solar power generation or feeding to the load side circuit. . Thereby, deterioration of the battery 11 can be prevented and the lifetime can be further increased.

FIG. 6 is a flowchart showing power source selection control of the photovoltaic power generation system 1, and shows details of step S30 in FIG.
As shown in FIGS. 2 and 6, the control device 17 determines whether or not charging by solar power generation is possible based on power generation information (voltage) detected by the power generation amount detector 13 (S32). When it is determined that charging by solar power generation is possible (YES in S32), the control device 17 opens the switch 22 connected to the output side of the pulse charger 5 (S33), and the output side of the solar charger 4 The switch 21 connected to is closed (S34). Thereby, the output side of the solar charger 4 is connected to the battery 11 via the switch 23, and the battery 11 of the power storage device 7 can be charged by the output of the solar cell panel 2.

  Thus, by using the solar cell panel 2 with priority based on the power generation status of the solar cell panel 2 detected by the power generation amount detector 13, the use efficiency of solar energy can be improved.

  On the other hand, when it is determined in step S32 that the output of the solar battery panel 2 is small and charging by solar power generation is not possible (NO in S32), the control device 17 opens the switch 21 on the output side of the solar charger 4. Open (S35).

  In step S36, it is determined whether or not the battery 11 is in a normal usable state. That is, the control device 17 determines whether the remaining capacity of the battery 11 detected by the detector 12 is equal to or greater than a predetermined reference value (first reference value). Specifically, it is determined whether the remaining capacities of all series of batteries 11 are equal to or greater than the first reference value.

  Specifically, the control device 17 determines whether the voltage of the battery 11 detected by the detector 12 is equal to or higher than a voltage value (first reference voltage value) corresponding to the first reference value of the remaining capacity. Note that the first reference value of the remaining capacity of the battery 11 is, for example, about 25% of the total charge capacity, and the first reference voltage value is about 12V.

  If the remaining capacities of all the series of batteries 11 are equal to or greater than the first reference value (YES in S36), the control device 17 opens the switch 22 (S37). That is, in this case, since the switch 21 and the switch 22 are both shut off, the battery 11 is not charged.

  On the other hand, when the remaining capacity of the battery 11 of at least one series is smaller than the first reference value in step 36 (NO in S36), the control device 17 determines whether or not it is a time zone in which nighttime power can be used. (S38).

  When night power can be used (YES in S38), the control device 17 opens the switch 27 for the external power source 60 that is normal power (S39), and closes the switch 28 for the external power source 61 that is night power ( S40). Then, the control device 17 closes the output-side switch 22 of the pulse charger 5 (S43). As a result, the battery 11 is charged using the nighttime power supplied from the external power supply 61.

  On the other hand, when night power cannot be used (NO in S38), the control device 17 opens the switch 28 for the external power source 61 that is night power (S41), and opens the switch 27 for the external power source 60 that is normal power. Close (S42). Then, the control device 17 closes the output-side switch 22 of the pulse charger 5 (S43). Thereby, the battery 11 is charged by the external power source 60 which is normal power.

  In this way, by using the external power sources 60 and 61 to charge only when the remaining capacity of the battery 11 falls below the first reference value, the storage capacity for photovoltaic power generation can be minimized while using external power to a minimum. It is possible to suppress overdischarge of the storage battery while ensuring the above. In addition, when night power can be used, the power cost can be reduced because the night power is used with priority.

FIG. 7 is a flowchart showing switching control of the output switch 30 of the photovoltaic power generation system 1, and shows details of step S50 in FIG.
As shown in FIGS. 2 and 7, the control device 17 determines whether or not the power storage device 7 is in a discharge prohibited state. That is, the control device 17 determines whether the remaining capacity of the battery 11 detected by the detector 12 is equal to or greater than a predetermined reference value (second reference value) (S52). Specifically, if the remaining capacity of at least one battery 11 is greater than or equal to the second reference value, it is determined that power storage device 7 is not in a discharge-inhibited state.

  Specifically, the control device 17 determines whether the voltage of the battery 11 detected by the detector 12 is equal to or higher than a voltage value (second reference voltage value) corresponding to the second reference value of the remaining capacity. The second reference value of the remaining capacity of the battery 11 is lower than the first reference value described above, for example, about 20% of the total charge capacity, and the second reference voltage value is about 11.7V. .

  If the remaining capacity of at least one battery 11 is greater than or equal to the second reference value (YES in S52), control device 17 opens switch 32 to which external power source 60 is connected (S53), and the output side of inverter 15 The switch 31 connected to is closed (S54). Thereby, the electric power stored in the battery 11 is supplied to the load side circuit.

  On the other hand, when the remaining capacities of all series of batteries 11 are lower than the second reference value in step 52 (NO in S52), the control device 17 opens the switch 31 connected to the output side of the inverter 15 (S55). Then, the switch 32 connected to the external power source 60 is closed (S56). That is, the output side circuit and the load side circuit of the inverter 15 are shut off (S55), and the external power source 60 and the load side circuit are connected (S56). Thereby, electric power is supplied from the external power supply 60 to the load side circuit.

  As described above, when the remaining capacity of the power storage device 7 falls below the second reference value, the discharge of the battery 11 can be stopped and the overdischarge can be prevented, so that the occurrence of sulfation is suppressed and the deterioration of the battery 11 is prevented. be able to. Further, even when the remaining capacity of the power storage device 7 is reduced and the discharge is stopped, the power can be supplied to the load side circuit using the external power source 60, so that stable power supply is possible. .

  FIG. 8 is a diagram showing the operation of detecting the remaining battery capacity of the solar power generation system 1, and shows details of step S60 in FIG. FIG. 8 shows an example in which the battery 11a has the largest remaining capacity, the battery 11b has the largest remaining capacity, and the battery 11c has the smallest remaining capacity.

  Referring to FIGS. 2 and 8, for example, when the remaining capacity of battery 11 detected by detector 12 has a relationship of “battery 11a> battery 11b> battery 11c”, battery 11a having the largest remaining capacity is discharged. Among the batteries 11b, the battery 11b, which is the next largest, is on standby (when sulfation is suppressed), and the battery 11c, which is the smallest, is being charged. That is, the discharge switch 24a connected to the battery 11a, the test / sulfation suppression switch 25b connected to the battery 11b, and the charge switch 23c connected to the battery 11c are closed, and the other switches 23 to 25 are Is blocked (S61).

  The control apparatus 17 switches the switch 26 to the detector 12 side, and switches the switches 23-25 sequentially in the order (S61-S76) shown in FIG. When the switch 26 is switched to the detector 12 side, the battery 11b in which the test / sulfation suppression switch 25b is closed is connected to the detector 12, and its remaining capacity is detected (S62). Then, the switch 25b connected to the battery 11b is opened (S63).

  Next, in steps S64 to S69, the control device 17 performs an operation for detecting the remaining capacity of the battery 11a. Specifically, after closing the discharge switch 24b connected to the battery 11b (S64), the discharge switch 24a connected to the battery 11a is opened (S65). As a result, power can be supplied from the battery 11b to the load side circuit while the remaining capacity of the battery 11a is detected.

  In this state, the control device 17 closes the inspection / sulfation suppression switch 25a connected to the battery 11a (S66), detects the remaining capacity of the battery 11a, and then opens the switch 25a (S67). Then, after closing the discharge switch 24a connected to the battery 11a (S68), the control device 17 opens the discharge switch 24b connected to the battery 11b (S69), and switches to the discharge by the battery 11a.

  In this way, the remaining capacity of the battery 11a being discharged can be detected without interrupting the power supply from the power storage device 7 to the load side circuit. When the battery 11 to be discharged is switched, instantaneous power failure can be caused by closing the switch 24a and the switch 24b at the same time instantly (for example, about 10 ms) as in steps S64 and S68. Continuous power feeding is performed without generating it.

  Next, in steps S70 to S75, the control device 17 executes an operation for detecting the remaining capacity of the battery 11c. Specifically, after closing the charging switch 23b connected to the battery 11b (S70), the charging switch 23c connected to the battery 11c is opened (S71). Thereby, while detecting the remaining capacity of the battery 11c, the electric power etc. which are generated with the solar cell panel 2 can be stored in the battery 11b.

  In this state, the control device 17 closes the inspection / sulfation suppression switch 25c connected to the battery 11c (S72), detects the remaining capacity of the battery 11c, and then opens the switch 25c (S73). Then, the control device 17 closes the charging switch 23c connected to the battery 11c (S74), then opens the charging switch 23b connected to the battery 11b (S75), and continues to charge the battery 11c. .

  In this manner, the remaining capacity of the battery 11c being charged can be detected without interrupting the charging of the power storage device 7. Even when switching the battery 11 to be charged, as in steps S70 and S74, the switch 23b and the switch 23c are closed at the same time instantaneously (for example, about 10 ms), and continuous charging is performed. Is going.

  Next, the control device 17 closes the test / sulfation suppression switch 25b connected to the battery 11b (S76), switches the switch 26 to the pulse oscillator 6 side, and returns to the state before the remaining amount test is started.

  Thus, in this embodiment, while charging one battery 11 constituting the power storage device 7, power is supplied from the other battery 11 to the load side circuit (inverter or the like), and The remaining capacity of the other series of batteries 11 can be detected.

  And each series (battery 11a, 11b, 11c) of the electrical storage apparatus 7 is interrupted by switching the switches 23-25 of the charging / discharging switching device 20 without interrupting the charge by photovoltaic power generation, or the electric power feeding to a load side circuit. Can be sequentially connected to the detector 12 to accurately detect the remaining capacity of each series. Thereby, management of the charge / discharge status of the power storage device 7 is facilitated, and overdischarge of the battery 11 can be suppressed to suppress the occurrence of sulfation, thereby extending the life of the battery.

  In addition, when the remaining capacity of the battery 11 is detected, the charging of the power storage device 7 is not interrupted. Therefore, in a state where a sufficient amount of solar radiation is obtained, solar energy is effectively used without interrupting solar power generation. be able to.

  In addition, an inexpensive lead-acid battery can be used as the battery 11 and the battery 11 can be prevented from deteriorating to extend its life. Therefore, the initial cost of the system and the maintenance cost such as replacement of the battery 11 can be reduced. It can be greatly reduced.

  Next, an example in which the embodiment is modified will be described in detail with reference to FIGS. 9 to 11. 9 to 11, components having the same or similar functions and effects as those of the embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 9 is a block diagram showing an outline of a photovoltaic power generation system 101 according to another embodiment of the present invention. As shown in FIG. 9, the photovoltaic power generation system 101 includes a plurality of battery modules 3 (battery module 3A, battery module 3B, and battery module 3C) each having a power storage device 7 (see FIG. 1).

  Further, the photovoltaic power generation system 101 corresponds to load side circuits divided into a plurality of systems X, Y, and Z, respectively, and a plurality of inverters 15 (inverter 15x, inverter 15y, inverter 15z) and a plurality of load detections. 14 (load detector 14x, load detector 14y, load detector 14z) and a plurality of output switches 30 (output switch 30x, output switch 30y, output switch 30z). .

  Furthermore, the solar power generation system 101 includes a switching device 40 that alternatively connects the output side circuit of the battery module 3 to the inverter 15 corresponding to each of the systems X, Y, and Z on the load side. In addition, the number of systems of load side circuits, the number of battery modules 3 and the like may be four or more.

  FIG. 10 is a configuration diagram illustrating a wiring system of the switching device 40 of the solar power generation system 101. As illustrated in FIG. 10, the photovoltaic power generation system 101 includes three battery modules 3 (3A, 3B, and 3C) and is connected to a load side circuit that is divided into three systems X, Y, and Z. The output side of the inverter 15 is connected to the load side circuit of each system X, Y, Z via the switch 31 which comprises the output switch 30, respectively.

  Three switches 41, 42, and 43 constituting the switching device 40 are connected to the input side of the inverter 15 corresponding to each system X, Y, and Z, respectively. The switch 41 is a switch connected to the output side of the battery module 3A. The switch 42 is a switch connected to the output side of the battery module 3B. The switch 43 is a switch connected to the output side of the battery module 3C.

  Here, the switch 41, the switch 42, and the switch 43 connected to one inverter 15 are alternatively closed. For example, only one of the switch 41x, the switch 42x, and the switch 43x connected to the inverter 15x is selected and closed. In other words, the inverter 15 connected to one of the systems X, Y, and Z is connected to any one battery module 3 selected from the battery module 3A, the battery module 3B, and the battery module 3C.

  Moreover, the switch 41, the switch 42, or the switch 43 connected to one battery module 3 is closed only with respect to the inverter 15 of one system, respectively. That is, the switch 41x, the switch 41y, and the switch 41z connected to the battery module 3A are alternatively closed. For example, when the switch 41x is closed, the switch 41y and the switch 41z are blocked.

Similarly, the switch 42x, the switch 42y, and the switch 42z connected to the battery module 3B are alternatively closed. Further, the switch 43x, the switch 43y, and the switch 43z connected to the battery module 3C are alternatively closed in the same manner.
That is, the plurality of battery modules 3 provided by the switching device 40 and the inverters 15 connected to the load-side circuits of the respective systems are connected so as to correspond one-to-one.

  Further, an output switch 30 is provided on the output side of the inverter 15 connected to each system X, Y, Z. The configuration and operation of the output switch 30 are the same as those in the embodiment described above. Here, the output switch 30 of each system X, Y, Z is controlled according to the remaining capacity of the battery 11 (see FIG. 1) of the battery module 3 connected to the system X, Y, Z.

  The load detector 14 is a device that detects the power load of each system X, Y, Z, and is provided on the input side of each inverter 15. Specifically, the load detector 14 detects the voltage of the shunt resistor provided in the input side circuit of the inverter 15, converts it to a digital signal, and outputs it to the control device 18.

  The control device 18 is a device that performs switching control between each system X, Y, and Z of the battery module 3 and the load side circuit. A signal related to the power load is input from the load detector 14 to the control device 18, and a signal related to the remaining capacity of the battery 11 of each battery module 3 is input from the control device 17 (see FIG. 2).

  The control device 18 includes the power load of each system X, Y, Z detected by the load detector 14 and the battery of each battery module 3 detected by the detector 12 (see FIG. 2) and transmitted from the control device 17. A predetermined calculation is executed based on the remaining capacity of 11, and the opening / closing of the switches 41 to 43, 31, 32 is controlled.

  FIG. 11 is a diagram illustrating an example of a switching pattern of the switching device 40 of the solar power generation system 101. In FIG. 11, the power load of the load side circuit has a relationship of “system X> system Y> system Z”, and the remaining capacity of the battery module 3 has a relationship of “battery module 3A> battery module 3B> battery module 3C”. An example of the case is shown.

  As shown in FIGS. 10 and 11, the control device 18 sequentially determines the remaining capacities from the systems X, Y, and Z in descending order of power load based on the power loads of the systems X, Y, and Z and the remaining capacities of the battery modules 3. A battery module 3 having a large size is connected in correspondence.

  That is, in the example of FIG. 11, the switch 41x is closed and the battery module 3A having the largest remaining capacity is connected to the system X having the largest power load. Next, for the system Y with the large power load, the switch 42y is closed, and the battery module 3B having the second largest remaining capacity is connected. For the system Z having the smallest power load, the switch 43z is closed and the battery module 3C having the smallest remaining capacity is connected.

  As the remaining capacity of the battery module 3, a value obtained by averaging the detected values of the remaining capacity of the batteries 11 (see FIG. 2) included in each battery module 3 for each battery module 3 is used.

  As described above, according to the present embodiment, by combining a plurality of battery modules 3, a large-capacity power storage system can be constructed using an inexpensive lead power storage location. In addition, by executing the switching control using the switching device 40, the battery 11 of the power storage device 7 (see FIG. 2) is prevented from being overdischarged, and the life of the battery 11 is increased, while being highly efficient and stable. Power supply can be performed.

  In addition, this invention is not limited to the said embodiment, In addition, a various change implementation is possible in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation system 2 Solar cell panel 3, 3A, 3B, 3C Battery module 4 Solar battery charger 5 Pulse charger 6 Pulse oscillator 7 Power storage device 11, 11a, 11b, 11c Battery 12 Detector 13 Power generation amount detector 14 , 14x, 14y, 14z Load detector 15, 15x, 15y, 15z Inverter 17 Controller 20 Charge / discharge switching device 21, 22, 27, 28 Switch 23, 23a, 23b, 23c Switch 24, 24a, 24b, 24c Switch 25, 25a, 25b, 25c Switch 26 Switch 30, 30x, 30y, 30z Output switch 31, 31x, 31y, 31z Switch 32, 32x, 32y, 32z Switch 40 Switch 41, 41x, 41y, 41z Switch 42, 42x, 42y, 42z Switch 41, 41 , 41y, 41 z switches 60, 61 external power supply

Claims (6)

A first charger that charges the power storage device with the output of the solar panel;
A second charger that charges the power storage device with an external power source;
A detector for detecting a remaining capacity of the power storage device;
An inverter that converts the power stored in the power storage device and supplies it to a load side circuit,
The power storage device has three or more series composed of lead acid batteries,
One series selected from the series is connected to the output side circuit of the first charger or the second charger, the other series is connected to the input side circuit of the inverter, and another series is connected A solar power generation system comprising opening / closing means connected to the detector.   By switching the open / close means, each series of the power storage devices is sequentially connected to the detector to detect the remaining capacity for each series, and based on the detection result, the series with the smallest remaining capacity is connected to the first charge. The solar power generation system according to claim 1, wherein the solar power generation system is connected to a charger or the second charger. A pulse oscillator connected to the power storage device to generate a pulsed voltage, and
By switching the opening and closing means, one series of the power storage device is connected to the output side circuit of the first charger or the second charger, and the other series is connected to the input side circuit of the inverter, The photovoltaic power generation system according to claim 1, wherein another series is connected to the pulse oscillator.   2. The system according to claim 1, wherein the series is connected to the output side circuit of the second charger only when the remaining capacity of at least one series of the power storage device becomes smaller than a predetermined value. 4. The solar power generation system according to any one of 3 above. An output switch for selecting any one of the output side circuit of the inverter and the external power source and connecting it to a load side circuit;
When the remaining capacity of all the series constituting the power storage device becomes smaller than a predetermined value, the output switch and the load circuit are shut off by switching the output switch. The photovoltaic power generation system according to any one of claims 1 to 4, wherein a power source is connected to the load side circuit. A plurality of power storage devices;
The load side circuit divided into a plurality of systems;
A load detector for detecting the power load of each system;
A switching device that selectively connects the output side circuit of the power storage device to each of the systems,
By switching the switching device based on the remaining capacity of each power storage device detected by the detector and the power load of each system detected by the load detector, the remaining capacity increases in order from the system having the largest power load. The photovoltaic power generation system according to any one of claims 1 to 5, wherein the power storage devices are connected in association with each other.

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