JPH03164035A - Solar generation system - Google Patents

Abstract

PURPOSE:To expand the battery lives of battery facilities for power storage and to supply stable power without deteriorating the battery capacity by changing over plural battery facilities for power storage in order after completely discharging said battery facilities when the power supply from the solar generation facility is insufficient. CONSTITUTION:While it is judged not duration of sunshine T1, the power is supplied from a battery facility 5 for power storage to power receiving load, and while it is judged duration of sunshine T1, close instructions are issued from a switch controller 9 to switches 7 and 8. At this time, surplus power is stored in the battery facilities 5 and 6 for power storage, and the facilities 5 and 6 for power storage are charged 100%. When the duration of sunshine T1 at the first day passes, close instructions are output successively to the switch 7, and also a close instruction is output to the switch 8. The power stored in the battery facility 5 for power storage is discharged completely at night.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a solar power generation system that performs power interchange between solar cells and power storage battery equipment.

B. Summary of the Invention The present invention provides a power storage battery that requires complete discharge in a solar power generation system that provides alternating current power to a receiving load by accommodating power between a solar power generation facility and a power storage battery facility. By providing multiple pieces of equipment and switching them in order after they are fully discharged, the battery life of each power storage battery equipment can be improved and stable power can be supplied to the receiving load.

C. Conventional technology From the perspective of energy conservation, power generation technologies that effectively utilize natural energy such as sunlight and wind power are being considered. Although this natural energy has the disadvantage that the supply amount is affected by natural phenomena such as weather, it is seen as promising because it can provide an unlimited and clean energy source.

Among these natural energy sources, solar cells that utilize sunlight generate light energy that is given to electrons by the photovoltaic effect of the semiconductor when it receives light with energy above a certain value, creating electrons and holes near the PN junction. occurs. Electrons and holes near the PN junction are attracted by the internal electric field, electrons are attracted to the N-type region, holes are attracted to the P-type region, the N-type region becomes negative, and the hole is attracted to the P-type region.
The mold region is positively charged and an electromotive force is generated. If this solar cell is used, as long as the irradiation of light continues, it is possible to convert light energy into electrical energy and extract it as electricity.

However, in solar power generation equipment using solar cells, the output of the solar cells varies greatly depending on the intensity of sunlight, so
Surplus electricity occurs during sunny hours when sunlight is sufficiently strong, and when sunlight is weak or at night, there is insufficient electricity for the receiving load, making it impossible to stably supply electricity. Therefore, in order to supply stable power to the receiving load, surplus power generated during sunshine hours is stored in power storage battery equipment.
A solar power generation system has been devised that more effectively utilizes the output of solar power generation equipment by releasing stored power from power storage battery equipment when the power supplied to the receiving load decreases.

Conventionally, there is a solar power generation system of this type configured as shown in FIG. According to this solar power generation system, DC power generated by a solar power generation facility 51 using solar cells is supplied to an orthogonal conversion device 53 via a charge/discharge control device 52, where it is converted to AC power and step-up and transformed. The voltage is boosted by the power converter 54 and transmitted to the receiving load. At this time, if the sunlight is strong enough and surplus power is generated, the surplus power is controlled by the charge/discharge control device 52 and charged into the power storage battery equipment 55. In addition, when sunlight is weak or at night, stored power is transferred from the power storage battery equipment 55 to the charge/discharge control device 5.
2 to the receiving load in the same manner as described above.

Currently, lead-acid batteries are mainly used in the power storage battery equipment 55 of solar power generation systems, but lead-acid batteries are called so because they significantly shorten the battery life if the battery voltage drops too much due to over-discharge. It could only be used at a practical capacity of about 60 to 65% of its capacity.

Therefore, in order to utilize solar power generation systems efficiently, a new type of power storage battery equipment that can store large amounts of power is required. As this type of new power storage '16 pond facility,
For example, there is a zinc monobromine battery that uses zinc as the active material of the cathode. This zinc-bromine battery is resistant to overdischarge and has a nominal capacity of 1
A major advantage over conventional lead-acid batteries is that they can be used at a practical capacity of 0.00% and can be discharged by 100% without any problem. When this zinc-bromine electricity is applied to a solar power generation system, the stored power can be reduced to approximately 100%.
% effective use, and the stored power can be stably supplied to the power receiving load when sunlight is weak or at night.

However, in this zinc monobromine battery, if discharging is not completely completed during discharging, there is a risk that zinc will not be properly deposited in the next discharge, resulting in deterioration of battery performance. For this reason, in a secondary battery that requires complete discharge, such as a zinc-bromine battery, it is desirable to complete the discharge each time.

D. Problems to be Solved by the Invention In the solar power generation system described in the prior art, there is a method for stably supplying power to the receiving load by interconnecting the solar power generation equipment 5l and one power storage battery equipment 55. It is being If a zinc monobromine battery that requires complete discharge is adopted as the electric power storage electrical equipment 55, one zinc monobromine battery will have to back up the power shortage of the solar battery power generation facility 6i51. 51 Power storage battery equipment (zinc monobromine battery) in preparation for power shortages 55
It is necessary to store sufficient electricity. therefore,
Zinc-bromine batteries cannot be completely discharged, and repeated charging and discharging in this state deteriorates battery performance.
There is a problem that sufficient voltage cannot be supplied to the receiving load in the final stage of discharge.

The present invention has been made in view of the above-mentioned problems, and it is possible to extend the battery life of power storage battery equipment by sequentially and periodically completely discharging power storage battery equipment that requires complete discharge. The purpose of the present invention is to provide a solar power generation system that can stably supply power to a receiving load without deteriorating battery performance.

E. Means for Solving the Problems In order to achieve the above object, the present invention performs power interchange between the solar power generation equipment and the power storage battery equipment, and improves the efficiency of the solar power generation equipment and the power storage battery equipment. In a solar power generation system that converts DC power into AC power and supplies it to a receiving load, a plurality of power storage battery facilities that require complete discharge are connected to the solar power generation facility through respective switches, The present invention is characterized in that the switch is controlled to open and close based on an opening/closing command from an opening/closing 4 control unit so as to sequentially switch the plurality of power storage battery facilities in a fully discharged state.

F. According to the structure according to the present invention, the opening/closing control is controlled based on the opening/closing command of the switch control unit, and when the power supplied from the solar power generation equipment is insufficient, the plurality of power storage battery equipment By keeping the batteries in a fully discharged state and switching them in order, power storage battery equipment that requires complete discharge can be completely discharged on a regular basis.

G. Embodiment A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing a schematic configuration of a solar power generation system according to the present invention, in which DC power generated by a solar power generation facility 1 using solar cells is transmitted via a charge/discharge control device 2. The DC power is supplied to the orthogonal conversion device 3, where the DC power is converted to AC power at a commercial frequency, and the voltage is stepped up by the step-up transformer 4, and the power is transmitted to the receiving load. The configuration up to this point is the same as the configuration of the conventional solar power generation system (FIG. 5).

This solar power generation system requires new power storage battery equipment that can store large amounts of electricity. Examples of this new type of power storage battery equipment include zinc monobromine batteries that use zinc as the active material of the cathode. As mentioned in the conventional technology, zinc-bromine batteries are resistant to overdischarge and have a storage power of 10%.
It has the feature that it can be used at 0%. However, when this zinc monobromine battery is used in a solar power generation system, it is required to completely discharge the battery.

Therefore, in this embodiment, two power storage battery facilities 5 and 6 using zinc-bromine batteries are provided, and a charge/discharge control device is connected to these power storage battery facilities 5 and 6 via switches 7 and 8. 2
The power storage battery equipment 5, 6 is controlled to open and close based on the opening/closing command from the switch control section 9 of the switch 7.8, so that the power storage battery equipment 5, 6 is completely discharged in order. In addition, since zinc-bromine batteries can generate a current that is more than twice the rated current during discharge, two power storage battery installations @ 5.6
Set to the nominal capacity of the block for 00% power storage capacity,
During discharging, one of the power storage battery equipment 5 or 6 was discharged at the rated current.

By controlling the opening and closing of the above-mentioned switches 7.8 and 8 based on the opening and closing commands from the switch control unit 9, the surplus power of the solar power generation facility is transferred to each power storage battery facility 5 via the charge/discharge control device.
．． 6, and when the power supplied from the solar power generation equipment 1 is insufficient, each power storage battery equipment 5, 6 is completely discharged in turn, and this stored power is sent to the power receiving load via the charge/discharge control device 2. supply

The switch control unit 9 used here determines whether or not it is the sunshine hours when surplus power is generated based on the analog amount from the optical sensor 10 that provides an analog output proportional to the amount of received light, and also performs voltage detection. Based on the battery voltage of each power storage battery equipment 5, 6 detected by the device 11, 12, it is determined whether or not it is in a fully discharged state, and based on these determination results, opening/closing commands are given to the switches 7, 8.

The operation of the solar power generation system configured as described above will be explained according to the time chart shown in FIG. 2. At time O on the first day, it is assumed that one power storage battery equipment 5 is fully charged and the other power storage battery equipment 6 is not charged. First, at 0:00 on the first day, a close command is output from the switch control unit 9 to the switch 7, and only the charged power storage battery equipment 5 is connected to the charge/discharge control device 2.

At the same time, the switch control unit 9 changes the setting value to the optical sensor 10.
The analog outputs of the two are compared and it is determined whether it is the sunshine time period TI in which surplus power is generated. Here, sunshine period T
While it is determined that it is not 1, the power supplied to the solar power generation facility #iI is insufficient, so the stored power is received from the power storage battery facility 5 via the switch 7 and the charge/discharge control device 2. The amount of charge in the power storage battery equipment 5 decreases as the power is supplied to the load. Then, the sunlight becomes stronger and the switch control unit 9
Sunshine time period T. when surplus power is generated. While it is determined that this is the case, the switch control unit 9 outputs a closing command to the switches 7 and 8. Based on this closing command, the contacts of the open/close contacts 7 and 8 are closed, and both of the power storage battery equipment 5 and 6 are connected to the charge/discharge control device 2 . At this time, solar power generation equipment ■
Since surplus power is generated in
, 6, and each power storage battery device @ 5, 6 is lOO
charged to %. After that, the sunshine period T1 on the first day
When the time has passed, the switch control unit 9 continues to output a close command to the switch 7 and outputs an open command to the switch 8. Thereby, only the power storage battery equipment 5 that did not perform a complete discharging operation last time is connected to the charge/discharge control device 2. The power stored in this power storage battery installation OW5 is transmitted to the power receiving load via the charge/discharge control device 2, and is completely discharged during the night.

At this time, if the switch control unit 9 determines that the battery is in a fully discharged state based on the battery voltage of the power storage battery device @5 detected by the voltage detector 1l, an opening command is output to the switch 7. At the same time, a close command is output to the switch 8. Each switching gain 7, 8 is switched based on this opening/closing command, and the fully charged power storage battery device @6 is connected to the charging/discharging control device 2. Thereafter, until the switch control unit 9 determines the sunshine hours T during which surplus power will be generated on the second day, the stored power is transferred from the power storage electrical installation Is6 to the switch 8 and the charging/discharging control device. 2 to the receiving load, and the amount of charge in the power storage battery device +7f6 decreases. and,
When the sunshine hours T on the second day are determined by the switch control unit 9, a close command is output to the open/close 2Xs 7 and 8, and both power storage battery equipment 5 and 6 are connected to the charge/discharge control device 2. Connected. During this sunshine time period T, surplus power from the solar power generation equipment 1 is stored in each power storage battery equipment 5, 6 via the charge/discharge control device 2, switches 7, 8.

Thereafter, by repeating the same control pattern as described above, the surplus power of the solar power generation facility 1 is stored in each power storage battery facility 5, 6, and when the power supply of the solar power generation facility (@1 is insufficient), It is possible to switch and connect one of each power storage battery equipment 5, 6 in a completely discharged state.

Therefore, according to such a structure, the power storage battery equipment 5, 6 which requires multiple complete discharges, the switches 7, 8
The plurality of power storage battery facilities 5, 6 are completely discharged by connecting them to the solar power generation facility (1) via the solar power generation facility (1) and controlling the opening and closing of the switches 7, 8 based on the opening and closing commands from the switch control unit 9. Since it is possible to switch in order in the same state, it is possible to completely discharge each power storage battery equipment 5, 6 on a regular basis. As a result, when a secondary battery such as a zinc-bromine battery that requires a complete battery is used in the power storage battery equipment 5, 6, deterioration of battery performance can be prevented by completely discharging it periodically. As a result, the life of the battery can be significantly extended, and it can be used at almost 100% of its nominal capacity, allowing it to stably supply sufficient power to the receiving load in the final stage of discharge. be able to.

Furthermore, the zinc monobromine battery has the feature that there is no problem even if a current more than twice the rated current is generated during discharge. Taking advantage of this feature, two electric power storage electrical equipment 5,
Since 5.6 can be set to the nominal capacity of the block for the same power storage capacity as the power storage battery equipment of the prior art, the power storage battery equipment 5.6 originally has a smaller volume than the prior art. 6 can be made even more compact.

Next, a second embodiment of the present invention will be described based on FIGS. 3 and 4.

In this embodiment, as shown in FIG. 3, the same polarity of each power storage battery equipment 5, 6 is connected via a switch 3l, and at the final stage of discharging, the other power storage battery equipment 5 or 6 is connected to each other through a switch 3l. The configuration is such that a reverse voltage is applied to force the discharge, and the other configurations are the same as those of the first embodiment described above, so they are omitted. This switch 3l is controlled to open and close based on an opening and closing command from the switch control section 9. In this case, when the battery voltage of the power storage battery equipment 5 or 6 in the discharge state detected by the voltage detector 11.12 drops to a certain value, the switch control unit 9 sends a predetermined signal to the switch 3I. A close command is given for a period of time. For example, as shown in the time chart of FIG. 4, when one of the power storage battery equipment 5 reaches the final discharge period,
As in the first embodiment, the switches 7 and 8 are switched by an opening/closing command from the switch control section, and the other fully charged power storage battery equipment 6 is connected to the charge/discharge control device.

At this time, the switch 3l is closed for a predetermined time Δt by the closing command from the switch control unit 9, and a reverse voltage is applied from the other power storage battery equipment 6 to the power storage battery equipment 5 that has reached the final discharge period. . In this case, as shown in Figure 3, the resistor 3
2, it is also possible to limit the value of the discharge promoting current.

Therefore, according to such a configuration, when one power storage battery equipment 5 or 6 reaches the final discharge period, a reverse voltage is applied from the other power storage battery equipment 6 or 5 that has completed charging. Since discharging can be forced, complete discharging of each power storage battery equipment 5, 6 can be further promoted compared to the first embodiment described above.

Note that the present invention is not limited to the above embodiments,
Various modifications can be made without changing the gist.

For example, in the above embodiment, an optical sensor that can obtain an analog output proportional to the amount of received light is used as a means to identify the sunshine hours when surplus power is generated, but a set timer is used to identify the sunshine hours when surplus electricity is generated. It can also be specified.

H. Effects of the Invention As described in Section 2, according to the present invention, by providing a plurality of power storage battery equipment that requires complete discharge, it is possible to switch each power storage battery equipment in turn to completely discharge the power storage battery equipment. Therefore, the life of the battery can be significantly extended, and stable power can be supplied to the power receiving load without deteriorating the battery performance.

[Brief explanation of the drawing]

Fig. 1 is a Bronnock diagram showing a schematic configuration of the first embodiment of the present invention, Fig. 2 is a time chart for explaining the same embodiment, and Fig. 3 is a main part of the second embodiment of the present invention. FIG. 4 is a time chart for explaining the same embodiment.
FIG. 5 is a block diagram showing the schematic structure of a conventional solar power generation system. 1... Solar power generation equipment, 2... Charge/discharge control device, 3
...Orthogonal transformer, 4...Step-up transformer, 5,6...
・Power storage battery equipment, 7, 8... Switch, 9... Switch control unit, 10... Optical sensor, 11.12... Voltage detector, 31... Switch, 32 ···resistance. Fig. 2 Gui A the k one (item ◇ 1 @ 1 Jun 辷 I column) me 1 mouth key 2 E] Fig. 5

Claims (1)

[Claims] (1) A solar power system that performs power interchange between the solar power generation equipment and the power storage battery equipment, converts the DC power of the solar power generation equipment and the power storage battery equipment into AC power, and supplies the AC power to the receiving load. In a photovoltaic power generation system, a plurality of power storage battery facilities that require complete discharge are connected to the solar power generation facility through respective switches, and the plurality of power storage battery facilities are fully discharged. A solar power generation system characterized in that the opening/closing of the switch is controlled based on an opening/closing command from a switch control unit so as to switch the switches in sequence.