JPH09163626A - Sunlight generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the economic utilization efficiency of a device by charging a storage battery by the electric power of a solar battery at the time of a parallel- operation mode and charging the storage battery by the electric power of a commercial electric power system at the time of a night mode in the case where the stored electric energy of the storage battery is not more than the electric energy estimated for use. SOLUTION: A control means 9 is operated so as to read the detection value of a power consumption detecting means 11 and to store the history data of the power consumption of a load 7 into a memory means 13, and average load power consumption per day is computed on the basis of the data. When the charge remainder of a storage battery 3 is not more than the average load power consumption, a control signal is sent to a charging and discharging circuit 4 and a chopper circuit 5, and the storage battery 3 is charged by the electric power of a solar battery 2 at the time of parallel- operation mode, and at the time of night mode, the storage battery 3 is charged by the electric power of a commercial electric power system 6. Therefore, the power supply to the load 7 for nearly one day can be performed in a self-support node and at the same time the charging for supplement is performed by using the inexpensive night electric power of the commercial electric power system 6, so that the economic utilization efficiency of a sunlight generator may be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar power generation system in which solar cells are connected to a commercial power system via an inverter, and in particular, when some accident occurs in the commercial power system,
The present invention relates to a solar power generation device capable of performing a self-sustaining operation in which power generated by a solar cell is supplied only to a home load when the interconnection operation is stopped.

[0002]

2. Description of the Related Art In recent years, a solar power generation device has been installed in which solar cells are installed in homes, factories, or regions and are connected to a commercial power grid of an electric power company, and surplus power of the solar cells flows backward to the commercial power grid. It has been put to practical use.

In a solar power generation device, a solar cell is connected to a commercial power system via an inverter, and a household load is connected to the output end of the inverter. As a result, the output of the solar cell is converted from direct current to alternating current, and the alternating current power is supplied to the commercial power system and household load.

By the way, in the conventional photovoltaic power generator, when the power failure occurs in the commercial power system due to a disaster or a lightning strike, the operation of the inverter is stopped, but the power supply to the household load is reduced. In order to supply electricity and effectively use the generated power of the solar cell, the operation of operating the inverter independently and disconnecting the interconnection to the commercial power system and supplying the power from the solar cell to the household load is being considered. There is.

In addition, in order to cover the required power at night when a power failure occurs, a power storage means consisting of a charger and a storage battery is interposed between the solar cell and the inverter, and the power obtained by self-sustaining operation is provided during the day. Supply to the load,
A method of charging the storage battery with the surplus power, discharging the storage battery at night, and supplying the power to the load is under study.

[0006]

However, in the conventional solar power generation device provided with the storage battery, when the commercial power system is out of service for a long time, the remaining charge amount of the storage battery during the self-sustained operation becomes insufficient, and the self-sustaining operation is not possible. There was a risk that it would not be possible to drive.

Therefore, in order to prevent such a situation,
Always charge the storage battery with the power from the commercial power grid,
It may be possible to maintain a predetermined amount of charge, but in this case it was always uneconomical to purchase electricity from the commercial power grid.

The present invention has been made in view of the above points, and aims at economical utilization of the entire apparatus and charges the electric power storage means with the amount of electric power determined according to the consumption state of the load. An object of the present invention is to prevent overcharging of the electric power storage means and to improve the utilization efficiency of the entire device.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a solar cell is connected to a commercial power system via an inverter, and a load is connected between the inverter and the commercial power system to convert the power of the solar cell to the inverter. A parallel operation mode in which power is supplied to the load and the commercial power system via the night mode, a night mode in which the inverter is stopped and only the power from the commercial power system is supplied to the load, and the inverter is disconnected from the commercial power system and a solar cell is connected. In a photovoltaic power generation device capable of switching operation among three independent operation modes in which electric power is independently supplied to a load, a power reserve means connected to a solar cell via a backflow prevention element and a power reserve means of the power reserve means. A stored power detection means for detecting the amount of stored power, a power consumption detection means for detecting the power consumption of a load, and a storage unit for storing history data of a value detected by the power consumption detection means. And, based on the history data of the power consumption stored in the storage means, the expected power consumption for a predetermined time is calculated, and when the stored energy amount of the power storage means is equal to or less than the expected power consumption, in the parallel operation mode. In the above, the electric power storage means is charged with electric power from the solar cell, and the control means for charging the electric power storage means with electric power from the commercial power system in the night mode is provided. .

By using this structure, it is possible to use the load for a predetermined time in the self-sustained operation mode, and there is no fear that the self-sustained operation cannot be performed. Further, during parallel operation, the power storage means is charged with the generated power from the solar cells, and the supplementary charge is performed with the purchased power from the commercial power system at night, so that the entire device can be economically used. .

Then, an average load power consumption per day is calculated on the basis of the load power consumption in the past several days, and the calculated power consumption is set as the expected power consumption. The load can be used under the same conditions as usual for one day.

In the self-sustained operation mode, when the stored power amount of the power storage means is equal to or less than the predetermined power amount, the fact is notified, and the operation of the inverter is stopped after a certain period of time to use the load. On the way, there is no fear that power supply will end suddenly without any notice. Further, as the predetermined power amount at that time, the average load power consumption amount per hour is calculated based on the load power consumption in the past several days, and the calculated power consumption amount is set as the predetermined power amount.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a solar power generation device to which the present invention is applied.

In the figure, a photovoltaic power generation device 1 includes a photovoltaic cell 2 for converting sunlight energy into DC power (in the present embodiment, a rated output voltage of 200 V and a rated power generation of 3 k).
W), the storage battery 3 as a power storage means connected to the solar cell 2 via the backflow prevention element, the charge / discharge circuit 4 for charging / discharging the storage battery 3, and the output voltage (= DC2) of the solar cell 2.
00V) to a predetermined voltage (= DC300V) and a chopper circuit 5 that converts the DC voltage from the chopper circuit 5 to a predetermined AC voltage (= 200V), which is connected to a commercial power system 6 and connected to a distribution line. An inverter circuit 8 that supplies electric power to a home load 7 such as various household appliances that have been created is mainly configured.

The inverter circuit 8 includes a plurality of (four in this embodiment) switching elements connected in a bridge,
For each switching element, a diode whose current-allowing direction is opposite is connected in parallel. This inverter circuit 8
A switching control signal is given to the circuit via a drive circuit 10 from a control means 9 for performing various processes described later, and the conduction of the switching element is controlled based on the control signal. The control means 9 is composed of a microcomputer.

The chopper circuit 5 includes a switching element 5
1, 52, the coil 53, the diodes 54 and 55, and the capacitors 56 and 57. The chopper circuit 5 performs a boosting operation by turning on / off the switching element 51 when the switching element 52 is off, and charges the capacitor 57. Then, the step-up ratio changes according to the ON period of the switching element 52. Further, this chopper circuit 5 turns off all the switching elements of the inverter circuit 8, and when supplying the power from the commercial power grid 6 to the storage battery 3, the switching element 52 is turned on when the switching element 51 is off. The DC voltage supplied via the diode of the inverter circuit 8 is supplied by. Then, the step-down ratio changes according to the ON period of the switching element 52 at that time, and the diode 54 is provided to protect the switching element 51 from reverse voltage during the OFF period of the switching element 52.

The storage battery 3 receives electric power from the solar cell 2 or the commercial power system 6 and is charge / discharge controlled by the charge / discharge circuit 4. In this embodiment, the storage battery 3 having a capacity of 15 kWh is used.

The charge / discharge circuit 4 detects the charge amount of the storage battery 3 and supplies the detection result to the control means 9, and
The storage battery 3 is charged or discharged based on a control signal from the control means 9.

A power consumption detecting means 11 for detecting the power consumption per unit time based on the current flowing through the load 7 is provided, and the detection result is input to the control means 9.

The control means 9 controls the parallel operation mode in which the electric power of the solar cell 2 is supplied to the load 7 and the commercial power system 6 through the inverter circuit 8 and the operation of the inverter circuit 8 is stopped so that the commercial power system 6 outputs the power. The night mode in which only the power is supplied to the load 7 and the self-sustained operation mode in which the interconnection circuit 12 is opened to disconnect the inverter circuit 8 from the commercial power system 6 and the solar cell 2 alone supplies the power to the load 7 Switching operation control is performed between two modes. Note that the control means 9 is normally set to the parallel operation mode, the generated power of the solar cell 2 decreases, and the interconnected operation becomes impossible, and the internal timer cannot expect the solar cell 2 to generate electric power. When the time comes, the mode is automatically switched to night mode. Further, the self-sustained operation mode is switched and set by a setting switch (not shown) provided outside the device.

Then, the control means 9 reads the value detected by the power consumption detecting means 11 and stores the history data of the power consumption of the load 7 per hour in the storage means 13 at any time. The storage unit 13 can store history data for the past 7 days, and the data is updated every hour. The control unit 9 calculates the average load power consumption per day of the load 7 based on the history data stored in the storage unit 13, and the charge remaining amount stored in the storage battery 3 is the calculated power consumption amount. In the following cases, a control signal is sent to the charging / discharging circuit 4 and the chopper circuit 5 to charge the storage battery 3 with the electric power from the solar cell 2 in the parallel operation mode and the commercial power system in the night mode. The storage battery 3 is charged with electric power from the battery 6.

As a result, in the self-sustaining operation mode, the load can be used for about one day in the same use condition as in the normal condition. In addition, since the storage battery 3 is charged by the generated power from the solar cell 2 during parallel operation, and the supplementary charge is performed by the purchased power from the commercial power system 6 at night when the usage fee is low,
The entire device can be economically utilized.

Further, the control means 9 calculates the average load power consumption per hour of the load 7 based on the history data stored in the storage means 13, and stores it in the storage battery 3 in the self-sustained operation mode. If the remaining charge amount is less than or equal to the calculated power consumption amount, a message to that effect is displayed on the notification means 14 provided in the apparatus main body, and after 15 minutes, a gate block signal is sent to the drive circuit 10. The operation of the inverter circuit 8 is stopped.

As a result, during the use of the load 7, the power supply does not suddenly end without any notice. Next, the operation of the solar power generation device will be described based on the flowcharts shown in FIGS. 2 to 4.

First, the operation contents in the parallel operation mode will be described with reference to FIG. First, in step S1,
Determine whether the current setting mode is parallel operation mode,
If yes, then continue with step S3; if no, continue with step S5.

In step S3, it is determined whether or not the interconnection operation is possible. If YES, the process proceeds to step S7 and N
In the case of O, the process returns to step S1. In this step S3, it is determined whether or not the output voltage and output current of the solar cell 2, the output current of the inverter circuit 8, the output voltage of the commercial power system 6 and the like are within the interconnection operable range.

On the other hand, if NO in step S1 and proceed to step S5, it is determined whether or not the current setting mode is the self-sustaining operation mode. If YES, the process proceeds to step S9, and if NO. It proceeds to step S11. Then, as will be described later, the process shown in FIG. 3 is performed in step S9, and the process shown in FIG. 4 is performed in step S11.

Next, in step S7, a connection command signal is sent to the connection switch 12 to connect the inverter circuit 8 to the commercial power system 6, and then a switching control signal is supplied to the inverter circuit 8. Start the inverter operation,
The power of the solar cell 2 is supplied to the load 7 and the commercial power system 6.

In the next step S13, the remaining charge amount of the storage battery 3 detected in the charge / discharge circuit 4 is read out, and the process proceeds to step S15. In step S15, the storage means 13
The average load power consumption per day of the load 7 is calculated on the basis of the history data stored in, and the calculated value is used as the expected daily power consumption, and the process proceeds to step S17.

In step S17, when the remaining charge amount stored in the storage battery 3 is less than or equal to the calculated expected power amount, a control signal is sent to the charging / discharging circuit 4 and the power from the solar battery 2 is used. Charge the storage battery 3, and step S1
Go to 9.

In step S19, similarly to step S3, it is determined whether or not the interconnection operation is possible. If YES, the process returns to step S13, and if NO, the process proceeds to step S21.

In step S21, the interconnection switch 12
To the drive circuit 10 to stop the supply of the switching signal to the inverter circuit 8 and to return to step S1.

The parallel operation mode is executed by repeating the above processing. Next, the operation content in the self-sustained operation mode will be described with reference to FIG.

First, in step S101, it is determined whether or not the self-sustaining operation is possible. If YES, step S10
When it is NO, the self-sustained operation mode is ended. In this step S101, it is determined whether or not the output voltage and output current of the solar cell 2, the output current and output voltage of the inverter circuit 8 and the like are within the self-sustainable operation range.

In step S103, the charge remaining amount of the storage battery 3 detected by the charge / discharge circuit 4 is read out, and the process proceeds to step S105. In step S105, the storage means 1
1 of load 7 based on the historical data stored in 3
The average load power consumptions for time and day are calculated, and the calculated values are set as the expected power consumption for one hour and one day, respectively, and the process proceeds to step S107.

In step S107, it is determined whether or not the remaining charge stored in the storage battery 3 is less than or equal to the calculated expected power consumption for one hour. If YES, the self-sustaining operation mode is ended, and if NO. Advances to step S109.

In step S109, the inverter circuit 8
A switching control signal to start the inverter operation, supply the electric power of the solar cell 2 to the load 7, and
There is surplus power in the power generation from the solar cell 2, and the storage battery 3
When the remaining charge amount is less than or equal to the rated capacity (= 15 kWh), a control signal is sent to the charge / discharge circuit 4, and the storage battery 3 is charged with the surplus power.

In the next step S111, the charging / discharging circuit 4 is
The remaining charge of the storage battery 3 detected in step S113 is read, and the process proceeds to step S113. In step S113, it is determined whether or not the remaining charge amount of the storage battery 3 is less than or equal to the calculated expected power amount for one hour. If YES, step S115
If NO, the process proceeds to step S117.

In step S115, the fact that the remaining charge of the storage battery 3 is insufficient is displayed on the notification means 14, and after 15 minutes have elapsed, the process proceeds to step S119. Step S1
In step 17, as in step S101, it is determined whether or not the self-sustaining operation is possible, and if YES, step S109.
If NO, the process proceeds to step S119.

Then, in step S119, the gate block signal is sent to the drive circuit 10 to stop the supply of the switching signal to the inverter circuit 8 to stop the inverter operation, and then the self-sustained operation mode is ended.

The self-sustaining operation mode is executed by repeating the above processing. Next, the operation contents in the night mode will be described with reference to FIG.

First, in step S201, it is determined whether or not the power generated by the solar cell 2 is in a state in which interconnection is possible,
If YES, the night mode is ended, and if NO, the process proceeds to step S203.

In step S203, the internal timer determines whether or not the current time is between 23:00 pm and 3:00 am. If YES, the process proceeds to step S205, and if NO, the process returns to step S201.

In step S205, the remaining charge amount of the storage battery 3 detected by the charge / discharge circuit 4 is read out, and the process proceeds to step S207. In step S207, the storage unit 1
1 of load 7 based on the historical data stored in 3
The daily average load power consumption is calculated, and the calculated value is set as the estimated daily power consumption, and the process proceeds to step S209.

In the next step S209, it is determined whether or not the remaining charge amount stored in the storage battery 3 is less than or equal to the calculated expected power amount, and if YES, step S211.
If NO, the process returns to step S201.

In step S211, a control signal is sent to the charging / discharging circuit 4 and the chopper circuit 5, and the commercial power system 6
The storage battery 3 is charged with the electric power from step S205.
Return to

By repeating the above process, the auxiliary charging of the storage battery 3 in the night mode is executed. The above description of the embodiments is for explaining the present invention, and limits the invention described in the claims,
Or should not be construed as reducing the range. In addition, the configuration of each part of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[0048]

As described above, according to the present invention, it is possible to use a load for a predetermined time in the self-sustaining operation mode, there is no fear that the self-sustaining operation cannot be performed, and economical use of the entire apparatus is possible. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a photovoltaic power generation apparatus showing an embodiment of the present invention.

FIG. 2 is a flowchart showing operation contents in a parallel operation mode.

FIG. 3 is a flowchart showing the operation contents in a self-sustained operation mode.

FIG. 4 is a flowchart showing the operation contents in night mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photovoltaic power generator 2 Solar cell 3 Storage battery (electric power storage means) 4 Charging / discharging circuit (stored power detection means) 5 Chopper circuit 6 Commercial power system 7 Load 8 Inverter circuit 9 Control means 10 Drive circuit 11 Power consumption detection means 12 stations System switch 13 Storage means 14 Notification means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H02M 7/48 9181-5H H02M 7/48 R 9181-5H N H02N 6/00 H02N 6/00 ( 72) Inventor Masahiro Maekawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. A solar cell is connected to a commercial power system through an inverter, a load is connected between the inverter and the commercial power system, and the power of the solar cell is transferred to the load and the commercial power system through the inverter. Parallel operation mode to supply,
The night mode in which the inverter is stopped and only the power from the commercial power grid is supplied to the load, and the self-sustaining operation mode in which the inverter is disconnected from the commercial power grid and the solar cell alone supplies the power to the load In a photovoltaic power generation device capable of switching operation between two modes, a power reserve means connected to a solar cell via a backflow prevention element, a reserve power detection means for detecting the reserve power amount of the power reserve means, and a load Power consumption detecting means for detecting the power consumption of the device, storage means for storing history data of detection values by the power consumption detecting means, and use for a predetermined time based on the history data of power consumption stored in the storage means. When the estimated power amount is calculated and the stored power amount of the power storage means is equal to or less than the expected power amount to be used, the power storage is performed by the power from the solar cell in the parallel operation mode. Which charges the stage, photovoltaic device, characterized by comprising a control means for charging the power reserve means with electric power from the commercial electric power system at night mode. 2. The control means calculates an average load power consumption amount per day on the basis of load power consumption in the past several days, and sets the calculated power consumption amount as the expected power consumption amount. The solar power generation device according to claim 1. 3. The control means, in the self-sustained operation mode, when the stored power amount of the power storage means is less than or equal to a predetermined power amount, informs the fact and stops the operation of the inverter after a lapse of a predetermined time. The solar power generation device according to claim 1 or 2. 4. The control means calculates an average load power consumption per hour on the basis of load power consumption in the past several days, and sets the calculated power consumption as the predetermined power amount. The solar power generation device according to claim 3.