JP5858356B2 - Solar power generation system - Google Patents

Description

  The present invention relates to a solar energy storage system.

  Electric devices such as refrigerators and servers (hereinafter abbreviated as “important loads” as necessary) are preferably continuously supplied even when the power supply line of the commercial system fails. .

  For this reason, an invention is known in which a solar battery or a storage battery is connected in parallel with a commercial system, and power is supplied to an important load by the solar battery or the storage battery when a power supply line of the commercial system fails (for example, Patent Document 1). reference).

  Using a solar cell leads to effective utilization of natural energy, and a stable power supply can be realized by connecting a storage battery in parallel with the solar cell.

  At this time, the voltage output by the solar battery and the storage battery is a direct current voltage and cannot be directly connected to a commercial system that is an alternating current voltage. Therefore, after the output of the solar battery is converted to an alternating current voltage by a power conditioner, The output of the storage battery is converted to an AC voltage by an inverter and then connected to a commercial system.

JP 2011-10412 A

  By the way, the value of the DC voltage output from the solar battery changes in accordance with the intensity of sunlight (irradiation intensity). When the solar radiation intensity is low such as in the morning or after the evening, the output voltage of the solar battery is small, and when the solar radiation intensity is high such as during the day, the output voltage of the solar battery is large.

  In Japan, the voltage of the commercial system is an AC voltage of 100V, but in order to convert the DC voltage by the power conditioner into an AC voltage of 100V, an operating voltage in a predetermined range (for example, 70V to 400V) is used as the power conditioner. Must be entered. In this specification, the operating voltage of the power conditioner refers to a DC voltage input to the power conditioner that is necessary for the power conditioner to output an AC voltage of the commercial system.

  Therefore, when the solar radiation intensity is low, such as in the morning or after the evening, the output voltage of the solar battery does not reach the operating voltage of the power conditioner (for example, less than 70V), and the power conditioner cannot convert the output of the solar battery into an AC voltage of 100V. .

  As a result, in the configuration in which the power conditioner is connected to the solar battery as in the invention described in Patent Document 1, the time period during which the solar battery output voltage does not reach the operating voltage of the power conditioner is low when the solar radiation intensity is low. However, the output of the solar battery cannot be converted into an AC voltage of 100 V, and the power generated by the sunlight is wasted. At this time, since a wasteful current flows through the solar battery, there is an adverse effect that the temperature of the solar battery rises and the efficiency of the solar battery decreases. Especially in summer, the temperature of the solar battery tends to rise because the ambient temperature is high and it is difficult to dissipate heat.

  Therefore, an object of the present invention made in view of such a point is to make effective use of the power output from the photovoltaic cell even when the output voltage of the photovoltaic cell does not reach the operating voltage of the power conditioner. It is to provide a solar energy storage system.

The invention of the photovoltaic power generation system according to the first aspect of achieving the above object is as follows:
An array of solar cell modules comprising a plurality of solar cell modules;
A power conditioner that converts a DC voltage generated by the array of solar cell modules into an AC voltage;
When the DC voltage is measured and the measured DC voltage does not reach the operating voltage of the power conditioner, a voltage determination unit that separates the array of the solar cell modules and the power conditioner;
A storage battery that stores direct current generated by the array of solar cell modules;
The storage battery is characterized in that when the DC voltage does not reach the operating voltage of the power conditioner, all of the DC current is used for storage.

  The invention according to a second aspect is the solar energy storage system according to the first aspect, and further converts the DC voltage generated by the array of solar cell modules into a DC voltage suitable for the storage battery. A charge / discharge controller is provided, and the storage battery receives a direct current from the charge / discharge controller.

  The invention according to a third aspect is the photovoltaic power generation system according to the first aspect, wherein the storage battery stores a direct current generated by a part of the solar cell modules in the array of solar cell modules. It is characterized by that.

  As described above, the solution of the present invention has been described as an apparatus. However, the present invention can be realized as a method, a program, and a storage medium storing the program, which are substantially equivalent thereto, and the scope of the present invention. It should be understood that these are also included.

  According to the present invention, it is possible to provide a photovoltaic power generation system capable of effectively utilizing the power output by a photovoltaic cell even when the output voltage of the photovoltaic cell does not reach the operating voltage of the power conditioner. Can do.

It is the schematic of the solar energy generation system which concerns on 1st Embodiment of this invention. It is a figure which shows the connection of the array of the solar cell module which concerns on 1st Embodiment of this invention, and a connection box. It is a figure which shows a mode that the output voltage of the array of a solar cell module changes with time. It is the schematic of the solar energy power generation system which concerns on 2nd Embodiment of this invention. It is a figure which shows the connection of the array of the solar cell module which concerns on 2nd Embodiment of this invention, and a connection box.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram of a photovoltaic power generation system according to the first embodiment of the present invention. The solar energy storage system 1 includes an array 11 of solar battery modules, a connection box 12, a voltage determination unit 13, a power conditioner 14, a charge / discharge controller 15, a storage battery 16, an inverter 17, and a charger 18.

  The array 11 of solar cell modules is configured by combining solar cell modules that are the minimum constituent units of solar cells. A solar cell module in which a plurality of solar cell modules are connected in series is referred to as a string, and the solar cell module array 11 is formed by connecting a plurality of strings in parallel.

  The solar cell module array 11 shown in FIG. 2 is an example in the case where strings of eight solar cell modules are connected in parallel. In FIG. 2, the solar cell module is abbreviated as “module”. Further, the number of solar cell modules shown in FIG. 2 is merely an example, and the string is not limited to a configuration from eight solar cell modules, and the solar cell module array 11 is limited to a configuration from two rows of strings. is not.

  As shown in FIG. 2, the connection box 12 receives the wiring from the array 11 of solar cell modules for each string, collects them into one, and then connects them to the power conditioner 14 via the voltage determination unit 13 and the charge / discharge controller. 15 to output to the storage battery 16.

  The voltage determination unit 13 measures a DC voltage output from the array 11 of solar cell modules. The voltage determination unit 13 determines whether or not the measured DC voltage is within the operating voltage range of the power conditioner 14, and if the DC voltage has not reached the operating voltage of the power conditioner 14, the voltage determination unit 13 The array 11 and the power conditioner 14 are separated. When the voltage determination unit 13 disconnects the solar cell module array 11 and the power conditioner 14, all of the direct current output from the solar cell module array 11 flows to the storage battery 16 via the charge / discharge controller 15.

  The power conditioner 14 converts the DC power received from the solar cell module array 11 through the junction box 12 and the voltage determination unit 13 into AC power. The power conditioner 14 also has an MPPT (Maximum Power Point Tracker) function, and can efficiently extract power from the array 11 of solar cell modules.

  The power conditioner 14 is connected to an outdoor power system (commercial system) 70 that supplies AC power to the distribution board 40 and is connected to the distribution board 40 via a watt hour meter 60. An electric device 50 is connected to the distribution board 40, and an AC voltage of 100 V is supplied from the distribution board 40 to the electric device 50. The electric device 50 is, for example, a general electric device for home use.

  The power conditioner 14 is completely stopped when the outdoor power system 70 fails. This is to prevent workers from getting an electric shock when constructing the outdoor power system 70.

  The DC power output from the solar cell module array 11 is supplied not only to the power conditioner 14 but also to the storage battery 16 via the connection box 12 and the charge / discharge controller 15.

  Since the DC voltage output from the array 11 of solar cell modules is equal to the voltage received by the power conditioner 14, it is usually higher than the voltage that can be input to the storage battery 16. Therefore, the charge / discharge controller 15 having the function of a DC / DC converter steps down the direct current voltage received from the connection box 12 to an appropriate voltage for the storage battery 16 and supplies it to the storage battery 16. The storage battery 16 is charged by a direct current that flows due to the received direct current voltage.

  The inverter 17 receives a DC voltage from the storage battery 16 and converts it into an AC voltage of 100V. The inverter 17 has a self-sustaining operation function. The inverter 17 is connected to an uninterruptible AC device 80 that is preferably supplied with electric power even when the outdoor power system 70 has a power failure. The uninterruptible AC device 80 is an important load such as a refrigerator.

  Since the charge / discharge controller 15, the storage battery 16, and the inverter 17 can be operated independently from the outdoor power system 70, the inverter 17 supplies 100 V AC to the uninterruptible AC device 80 even when the outdoor power system 70 fails. It is possible to supply power.

  Moreover, it is desirable that power is supplied even when the outdoor power system 70 has a power failure, and the uninterruptible DC device 90 that operates on direct current is directly connected to the storage battery 16 without the inverter 17. . Thereby, the storage battery 16 can prevent the accumulation of conversion loss due to two conversions from direct current to alternating current and alternating current to direct current as in the conventional case.

  The charger 18 receives AC power from the distribution board 40, converts it into DC power, and supplies it to the storage battery 16. Thereby, the charger 18 can store the storage battery 16 using the power supplied from the outdoor power system 70 even in the time zone such as the night when the array 11 of solar cell modules cannot generate power. it can.

  FIG. 3 shows how the output voltage of the array of solar modules changes with time. Since the output voltage of the solar module array 11 depends on the solar radiation intensity from the sun, the output voltage of the solar module array 11 is small in the time zone when the solar solar radiation intensity is low, such as in the morning or evening. For example, in the example shown in FIG. 3, before the time t1 and after the time t2, the output voltage of the solar module array 11 does not reach the operating voltage of the power conditioner 14 (for example, less than 70V).

  Therefore, at the time before t1 and after t2, the output voltage of the array 11 of solar cell modules does not reach the lower limit value (for example, 70V) of the operating voltage (for example, 70V to 400V) of the power conditioner 14. Therefore, in this case, the voltage determination unit 13 separates the array 11 of solar cell modules and the power conditioner 14.

  As a result, in the present embodiment, the direct current output from the array 11 of solar cell modules is all supplied to the storage battery 16 via the junction box 12 and the charge / discharge controller 15, and at times before t1 and after t2. All of the direct current output from the array 11 of solar cell modules can be used to store the storage battery 16.

  Thus, according to this embodiment, even if the output voltage of the solar battery does not reach the operating voltage of the power conditioner, the solar power generation that can effectively utilize the power output by the solar battery. A system can be provided.

  When the output voltage of the solar battery does not reach the operating voltage of the power conditioner, the voltage determination unit 13 disconnects the solar battery module array 11 and the power conditioner 14 and causes all current to flow through the storage battery 16. The useless current does not flow to the solar battery, and the efficiency of the solar battery can be prevented from being lowered due to the temperature rise of the solar battery caused by the useless current.

(Second Embodiment)
FIG. 4 is a schematic diagram of a photovoltaic power generation system according to the second embodiment of the present invention. The solar energy storage system 2 includes an array 21 of solar cell modules, a connection box 22, a voltage determination unit 13, a power conditioner 14, a storage battery 16, an inverter 17, and a charger 18. The solar power generation system 2 according to the second embodiment is different from the solar power generation system 1 according to the first embodiment in that the charge controller 15 is not provided. In addition, about the functional block with the same function as the functional block of the solar energy storage system 1 which concerns on 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The solar cell module array 21 is the same as the solar cell module array 11 of the first embodiment in that eight solar cell modules are arranged in parallel in two rows, but as shown in FIG. The wiring between the module 2 and the module 3 and the wiring between the module 10 and the module 11 are connected to the connection box 22 so that two series voltages can be taken out.

  In FIG. 5, the solar cell module is abbreviated as “module”. Further, the number of solar cell modules shown in FIG. 5 is merely an example, and the string is not limited to a configuration from eight solar cell modules, and the solar cell module array 21 is limited to a configuration from two rows of strings. is not.

  As shown in FIG. 5, the connection box 22 receives the wiring from the array 21 of the solar cell modules, combines them, and outputs them to the power conditioner 14 via the voltage determination unit 13, and also to the storage battery 16. Output. The connection box 22 outputs a series voltage for two solar cell modules to the storage battery 16, and outputs a series voltage for eight solar cell modules to the power conditioner 14 via the voltage determination unit 13.

  Here, the reason why the series voltage for the two solar cell modules is used as the input voltage of the storage battery 16 is to make the voltage appropriate for the storage battery 16. Therefore, supplying the series voltage for two solar cell modules to the storage battery 16 is merely an example, and the solar power necessary for the DC voltage supplied to the storage battery 16 according to the characteristics of the solar cell module and the storage battery 16. The number of battery modules varies.

  In the second embodiment, a direct current voltage is directly supplied from the connection box 22 to the storage battery 16 without using a charge / discharge controller. This is because a voltage of a part of the solar cell module array 21, that is, a DC voltage appropriate for the storage battery 16 is taken out from the connection box 22 instead of the entire voltage of the solar cell module array 21.

  Thus, according to the present embodiment, the charge / discharge controller can be omitted by adopting a configuration in which a part of the DC voltage of the array of solar cell modules is taken out and supplied to the storage battery.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the power conditioner may include the function of the voltage determination unit.

  Moreover, although the said embodiment demonstrated the solar cell as an example, this invention is not restricted to this, Renewable energy (It originates in a solar, geophysical, biological source, and is utilized by the natural world. It can also be realized by replacing batteries based on solar energy, wind power, wave power / tidal power, running water / tide, geothermal energy, biomass, etc.) that generally refer to energy replenished at a higher speed.

DESCRIPTION OF SYMBOLS 1, 2 Photovoltaic storage system 11, 21 Array of solar cell modules 12, 22 Connection box 13 Voltage judgment part 14 Power conditioner 15 Charge / discharge controller 16 Storage battery 17 Inverter 18 Charger 40 Distribution board 50 Electric equipment 60 Electricity meter 70 Outdoor power system 80 Uninterruptible AC equipment 90 Uninterruptible DC equipment

Claims (1)

An array of solar cell modules comprising a plurality of solar cell modules;
A power conditioner that converts a DC voltage generated by the array of solar cell modules into an AC voltage;
When the DC voltage is measured and the measured DC voltage does not reach the operating voltage of the power conditioner, a voltage determination unit that separates the array of the solar cell modules and the power conditioner;
A storage battery that stores direct current generated by the array of solar cell modules;
The storage battery, when the DC voltage does not reach the operating voltage of the power conditioner , stores the DC current generated by some solar cell modules of the array of solar cells,
When the DC voltage generated by the array of solar cell modules reaches the operating voltage of the power conditioner, the DC voltage generated by all the solar cell modules of the array of solar cell modules is output to the power conditioner. solar蓄power generation system characterized Rukoto is.

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