JPH09149554A - Solar-ray power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable independent operation to be performed continuously for a long period without enlarging the size of a solar-ray power generator. SOLUTION: This device has a parallel operation mode which supplies home load 5 with power, in cooperation with a commercial power system 4, and an independent operation mode which releases the parallel operation of the inverter circuit from the commercial power system 4. This is equipped with a control means 6 which enables the power supply to all of the home load 5 by closing a plurality of switching means 7-9 in parallel operation mod, and enables the power supply to only the specified home load 5 by closing only the specified switching means 7-9, according to the power capable of supply from a solar battery 2, in independent operation mode.

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 device, and more specifically, when the commercial power system experiences some accident and the interconnection operation is stopped, the power generated by the solar cell is applied only to the domestic load. The present invention relates to a solar power generation device capable of self-sustained supply.

[0002]

2. Description of the Related Art In recent years, a solar power generation system has been used in which a distributed power supply system of a comparatively small capacity of several kW using a DC power supply composed of solar cells is connected to a commercial power system via an inverter circuit to supply power to a load. Various devices have been put to practical use.

In the photovoltaic power generator, the solar cell is connected to the commercial power system via the inverter, and the 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 natural disaster such as an earthquake or a fire, the operation of the inverter is stopped, In order to effectively use the power supply from the solar cell and the generated power of the solar cell, the operation of operating the inverter independently to supply the power from the solar cell to the household load is considered with the grid connection to the commercial power grid disconnected. Has been done.

[0005]

However, in the conventional solar power generation device, the amount of power generated by the solar cell depends on the solar radiation conditions of the day, etc. Therefore, depending on the usage condition of the load during self-sustaining operation, There was a risk of causing a situation in which the self-sustained operation could not be continued due to insufficient power supply.

In order to prevent the above situation, a storage battery may be provided to increase the power that can be supplied from the solar cell. In this case, the rated power generation capacity of the solar cell itself should be increased accordingly. In addition to increasing the size of the solar power generation device, there is a risk that the entire device will be expensive due to the less frequently used self-sustaining operation.

The present invention has been made in view of the above circumstances, and provides a solar power generation device capable of continuously operating independently for a long period of time without increasing the size of the solar power generation device.

[0008]

The present invention comprises a solar cell,
An inverter circuit for converting DC power from the solar cell into AC power of a predetermined voltage, and a domestic load divided into a plurality of groups, a plurality of switching means for selectively connecting to the output side of the inverter circuit, A parallel operation mode in which the inverter circuit is connected to a commercial power system to supply power to a domestic load, and a stand-alone operation mode in which the inverter circuit is disconnected from the commercial power system to supply power to a domestic load independently. In parallel operation mode, it is possible to supply power to all domestic loads by closing a plurality of opening / closing means, and in independent operation mode, only a specific opening / closing means is provided according to the power that can be supplied from the solar cell. And a control unit that is closed to supply power only to a predetermined domestic load.

By using this configuration, in the self-sustaining operation mode, power is supplied only to a specific domestic load according to the power that can be supplied from the solar cells, so that self-sustaining operation can be continuously performed for a long period of time. it can.

Specifically, in the self-sustaining operation mode, the control means closes only a specific opening / closing means when a power that can be supplied from the solar cell is equal to or less than a set value, and a predetermined household is closed. The power can be supplied only to the internal load.

With this configuration, there is no fear that the power supplied from the solar cell will be insufficient and the self-sustaining operation cannot be continued. Further, preferably, in the self-sustaining operation mode, the control means sequentially opens the opening / closing means having the largest power consumption among the plurality of opening / closing means as the supplyable power from the solar cell decreases to a predetermined value. It is assumed that power can be supplied only to the domestic load.

By using this configuration, it is possible to use as much equipment as possible with low power consumption per unit time, and to keep the household load, which is desired to be continuously used in an emergency,
For example, a broadcast receiver such as a radio or a television can be continuously used.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a solar power generation device of the present invention will be described in detail with reference to the drawings showing an embodiment thereof.
FIG. 1 is a schematic configuration diagram of a solar power generation device using a solar cell to which the present invention is applied.

In the figure, a photovoltaic power generator 1 is 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 generated power of 3 k).
W) and an inverter circuit 3 that converts the generated power of the solar cell 2 into AC power and supplies a predetermined AC voltage (100 V in this embodiment), and is connected to the commercial power grid 4. Power is supplied to the domestic load 5 such as various home appliances connected to the distribution line.

The inverter circuit 3 is composed of a plurality of (four in this embodiment) switching elements connected in a bridge, and a switching control signal is given to the inverter circuit 3 from a control means 6 for performing various processes described later. The
The conduction of the switching element is controlled based on the control signal. The control means 6 is composed of a microcomputer.

On the output side of the inverter circuit 3, domestic loads 5a to 5c (rated capacity 1 kW) divided into a plurality of groups (three groups in this embodiment) are provided with first to third switches 7 as switching means. 9 to 9, respectively.

As the domestic loads 5a and 5b, it is possible to connect electric appliances whose load changes greatly during use.
An air conditioner and a vacuum cleaner can be connected to the domestic load 5a, a washing machine and an electric heater can be connected to the domestic load 5b, and the domestic load 5c has a small load fluctuation during use. In addition, electric appliances that are frequently used in an emergency, such as a television receiver, a lighting fixture, and an electric water heater, can be connected.

Further, an automatic restoration type interconnection switch 10 and a manual restoration type breaker 11 are provided between the domestic load 5 and the commercial power system 4 in order for system protection of the commercial power system 4. The interconnection switch 10 is opened and closed based on a control signal from the control means 6 to connect or disconnect the solar power generation device 1 to the commercial power system 4.

The control means 6 has a mode setting switch 20.
Is provided, and the inverter circuit 3 is connected to the commercial power system 4 by the setting by the switch 20 to supply electric power to the domestic loads 5a to 5c, and the inverter circuit 3 is operated from the commercial power system 4. It is configured such that it can be disconnected and an independent operation mode in which electric power is independently supplied to the domestic load 5 can be set.

When the parallel operation mode is set, if an abnormal state in the commercial power system 4 is detected, a disconnection command signal is sent to the interconnection switch 10 so that the solar power generation device 1 is moved from the commercial power system 4. At the same time as disconnecting, the supply of the switching control signal to the inverter circuit 3 is stopped.
When the solar cell 2 cannot generate power due to a decrease in the amount of solar radiation, the supply of the switching control signal to the inverter circuit 3 is stopped and the inverter operation is stopped.

Specifically, a detection value by the first voltage detecting means 21 including an isolation amplifier for detecting the output voltage of the solar cell 2 and a transformer (PT) for detecting the output voltage of the inverter circuit 3 are used. The value detected by the two-voltage detection means 22 is input, the start and stop of the inverter circuit 3 is controlled based on the detected value, and when an abnormality is detected on the commercial power system 4 side, the connection switch 10 and the breaker 11 are supplied. A disconnection command signal is being sent.

Then, the control means 6 controls the inverter output current by a first current detecting means 23 comprising a current transformer (CT) so that the active power supplied from the inverter circuit 3 becomes maximum.
The pulse width of the inverter circuit 3 is constantly monitored and the inverter output current is maximized.

On the other hand, when the self-sustained operation mode is set, first, the contact state of the interconnection switch 10 is detected, and after confirming that both are open, supply of the switching control signal to the inverter circuit 3 is started. Then, as will be described later, the first to third switches 7 to 9 are opened / closed in accordance with the generated power of the solar cell 2 so that power can be supplied only to a predetermined domestic load.

Specifically, the current power that can be generated from the solar cell 2 is calculated based on the value detected by the monitor voltage detection means 32 that is an isolation amplifier that detects the open circuit voltage of the monitor solar cell 31, and Based on the result, the opening / closing control of the first to third switches 7 to 9 is performed as described later.

Between the first to third switches 7-9 and the domestic loads 5a-5c, load current detecting means 33a-33 for detecting the power consumption of the domestic loads 5a-5c.
c is provided. Here, the load current detection means 33a
33c are configured by current transformers (CT), and in a second embodiment described later, the first to third switches 7-9 are switched as described later according to the power consumption of each domestic load 5a-5c. It controls opening and closing.

[Embodiment 1] First, the operation of the above photovoltaic power generator as an embodiment will be described with reference to the flowcharts shown in FIGS. 2 and 3.

First, the operation contents in the parallel operation mode will be described with reference to FIG. First, in step S1,
It is determined whether or not the inverter circuit 3 is in operation. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S3.

In step S2, it is determined whether or not the commercial power system 4 is in a normal state. If YES, the process proceeds to step S4, and if NO, the process proceeds to step S5. In this step S2, if the detected value by the second voltage detecting means 22 is within the range of 80V to 114V, it is determined that the commercial power system 4 is in the normal state, and if it is outside this range, it is determined as the abnormal state. ing.

If NO in step S2 and if the process proceeds to step S5, it is determined that the system is in an abnormal state, a disconnection command signal is sent to the interconnection switch 10, and switching to the inverter circuit 3 is performed. After the supply of the control signal is stopped to stop the inverter operation, the process returns to step S1.

In step S4, it is further determined whether or not the output of the solar cell 2 is in the interconnection enabled state by the first voltage detecting means 2
Judgment is made based on the detection value of 1 (when the detection value is 140 V or less, it is judged that the interconnection is impossible), and if NO is determined, the process proceeds to step S6. If YES is determined, the step S1 is performed. Return to.

Then, in step S6, it is judged to be in the standby state, the disconnection command signal is sent to the interconnection switch 10, the supply of the switching control signal to the inverter circuit 3 is stopped, and the process returns to step S1.

On the other hand, if NO in step S1 and if the process proceeds to step S3, it is determined whether or not the commercial power system 4 is in the normal state as in step S2, and YES.
In the case of, it progresses to step S7, and in the case of NO, it returns to the next step S1.

In step S7, similarly to step S4, it is determined whether or not the output of the solar cell 2 is in the interconnection-enabled state. If YES, the process proceeds to step S8, and if NO, the process returns to step S1.

In step S8, an interconnection command signal is sent to the interconnection switch 10 to connect the inverter circuit 3 to the commercial power system 4. Then, in the next step S9, a switching control signal is supplied to the inverter circuit 3 to start the inverter operation, and the solar cell is detected every predetermined time so that the inverter current detected by the first current detection means 23 becomes maximum. Mountain climbing method that changes the operating point of 2 (MPP
Control is performed by the T control method), and the process returns 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 confirmed whether the interconnection switch 10 is in an open state by detecting an abnormal state of the commercial power system 4. And step S
If YES in 101, the process proceeds to step S103,
If NO, the process returns to step S101.

In step S103, the current amount of power that can be generated by the solar cell 2 is calculated from the value detected by the monitor voltage detection means 32, and the process proceeds to step S105. Step S
At 105, it is determined whether or not the amount of power that can be generated by the solar cell 2 is approximately the rated amount of generated power (= 3 kW) (in the present embodiment,
(Whether it is 2.9 kW or more), and in the case of YES, the interconnection command signal is sent to all of the first to third switches 7 to 9 so that power can be supplied to the domestic loads 5a to 5c. After that (step S107), the process proceeds to step S109.

On the other hand, if NO in step S105, the process proceeds to step S111, in which it is determined whether or not the amount of power that can be generated by the solar cell 2 is 2 kW or more. If YES is determined in step S111, the process proceeds to step S113, the disconnection command signal is transmitted to the first switch 7, the interconnection command signal is transmitted to the second and third switches 8 and 9, and the home After making it possible to supply power only to the inner loads 5b and 5c, the process proceeds to step S109.

On the other hand, if NO in step S111, the process proceeds to step S115, in which the disconnection command signal is sent to the first and second switches 7 and 8, and the interconnection command signal is sent to the third switch 9. Then, after the power can be supplied only to the domestic load 5c, the process proceeds to step S109.

In step S109, the inverter circuit 3
Is supplied with a switching control signal to start the inverter operation, control is performed so that the inverter output voltage detected by the second voltage detection means 22 is maintained at the rated voltage (100 V), and the process proceeds to step S117.

In step S117, it is judged by the second voltage detecting means 22 whether the load voltage is normal, and YE
In the case of S, the process returns to step S103, and in the case of NO, the process proceeds to step S119. Here, the second voltage detection means 2
When the detected value by 2 is within the range of 80V to 114V, it is determined that the load voltage is in the normal state, and when it is outside this range, it is determined as the abnormal state.

In step S119, it is determined that the self-sustaining operation cannot be continued, the disconnection command signal is sent to the interconnection switch 10 and the first to third switches 7 to 9, and the switching control signal is supplied to the inverter circuit 3. And the inverter operation is stopped, and then the self-sustained operation mode is ended.

The self-sustaining operation mode is executed by repeating the above processing. [Embodiment 2] Next, the operation of the above photovoltaic power generator as another embodiment will be described with reference to the flowchart shown in FIG.

First, the details of the operation in the parallel operation mode are the same as those in the above-described first embodiment, and therefore detailed description thereof will be omitted. Next, the operation content in the self-sustained operation mode will be described with reference to FIG.

First, in step S201, it is confirmed whether the interconnection switch 10 is in an open state by detecting an abnormal state of the commercial power system 4. And step S
If YES in 201, the process proceeds to step S203,
If NO, the process returns to step S201.

In step S203, the current amount of power that can be generated by the solar cell 2 is calculated from the value detected by the monitor voltage detecting means 32, and the process proceeds to step S205. Step S
In 205, the amount of power that can be generated by the solar cell 2 is 2.9 kW.
If YES, it outputs a interconnection command signal to all of the first to third switches 7 to 9 so that the household loads 5a to 5c can be supplied with power (step S207). ) After that, it progresses to step S209.

On the other hand, if NO in step S205, the process proceeds to step S211, and it is determined whether or not the amount of power that can be generated by the solar cell 2 is 2 kW or more. If YES is determined in step S211,
Proceeding to step S213, load current detection means 33a-3
After detecting the power consumption of each home load 5a to 5c by 3c, the process proceeds to step S215.

In step S215, step S213
Of the domestic loads 5a to 5c obtained in step 5, the switching means (first switching device) to which the domestic load with the largest power consumption is connected
~ Send any disconnection command signal to any one of the third switches 7 to 9) and send interconnection command signals to the remaining opening / closing means,
After setting a state in which power can be supplied to a load other than the home load with the largest power consumption, the process proceeds to step S209.

When NO is determined in step S211, the process proceeds to step S217, and the load current detecting means 33a to 33c detect the power consumption of each domestic load 5a to 5c, and then the process proceeds to step S219.

In step S219, the above step S2 is performed.
Similarly to 15, the switching means (any one of the first to third switches 7 to 9) to which the domestic load having the largest power consumption is connected among the connected domestic loads 5a to 5c is connected.
After that, the parallel disconnection command signal is transmitted to the other opening / closing means, and the interconnection command signal is transmitted to the remaining opening / closing means to make it possible to supply power to the domestic load with the least power consumption, and then the process proceeds to step S209.

In step S209, the above step S1 is performed.
Similarly to 09, a switching control signal is supplied to the inverter circuit 3 to start the inverter operation, and control is performed so that the inverter output voltage detected by the second voltage detecting means 22 is maintained at the rated voltage (100V). , And proceeds to step S221.

In step S221, the above step S1
Similar to 17, the second voltage detection means 22 determines whether or not the load voltage is normal. If YES, the process returns to step S203, and if NO, the process proceeds to step S223.

In step S223, it is determined that the self-sustaining operation cannot be continued, the disconnection command signal is sent to the interconnection switch 10 and the first to third switches 7 to 9, and the switching control signal is supplied to the inverter circuit 3. And the inverter operation is stopped, and then the self-sustained operation mode is ended.

The self-sustained operation mode is executed by repeating the above processing. In the second embodiment, it is possible to use as many devices as possible with low power consumption per unit time, and to continuously use a household load that is desired to be continuously used in an emergency, for example, a broadcast receiver such as a radio or a television. It becomes possible to do.

As described above, according to the first and second embodiments,
In the self-sustaining operation mode, power is supplied only to a specific home load according to the power that can be supplied from the solar cell 2, so it is possible to avoid a situation where the power supply from the solar cell is insufficient and the self-sustaining operation cannot be continued. be able to.

In the above-described embodiment, the case where the transition from the parallel operation mode to the self-sustained operation mode is manually set by the mode setting switch 20 provided in the control means 6 has been described. The detection may be automatically performed at the same time.

Further, the household load to be supplied with electric power in the self-sustained operation mode is not limited to the above-mentioned embodiment, and the user may arbitrarily set it in advance.

[0058]

As described above, according to the present invention, in the self-sustained operation mode, electric power is supplied only to a specific domestic load according to the electric power that can be supplied from the solar cell, so that the electric power is continuously supplied for a long period of time. Can operate independently.

Further, as the power that can be supplied from the solar cell decreases, the opening / closing means having the largest power consumption among the plurality of opening / closing means is sequentially opened to supply the power only to a predetermined domestic load, thereby reducing the unit time. It is possible to use as much equipment as possible with low power consumption per hit, and it is possible to continue to use household loads that one wants to use continuously in an emergency.

Therefore, it is possible to continuously operate independently for a long period of time without increasing the size of the photovoltaic power generator, and to realize the miniaturization and cost reduction of the photovoltaic power generator.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a solar power generation device to which the present invention is applied.

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 of the first embodiment.

FIG. 4 is a flowchart showing operation contents in a self-sustained operation mode according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photovoltaic generator 2 Solar cell 3 Inverter circuit 4 Commercial power system 5 Home load 6 Control means 7 1st switch 8 2nd switch 9 3rd switch 10 Automatic restoration type interconnection switch 11 Manual restoration type breaker 12 Backflow prevention Diode 20 Mode setting switch 21 First voltage detection means 22 Second voltage detection means 31 Monitor solar cell

Claims (3)

[Claims] 1. A solar cell, an inverter circuit for converting DC power from the solar cell into AC power of a predetermined voltage, and a domestic load divided into a plurality of groups selectively on the output side of the inverter circuit. A plurality of opening / closing means connected to each other, a parallel operation mode in which the inverter circuit is connected to a commercial power system to supply electric power to a home load, and the inverter circuit is disconnected from the commercial power system to independently operate in the home. It has a self-sustaining operation mode for supplying electric power to a load, and in the parallel operation mode, it can supply electric power to all the domestic loads by closing a plurality of opening / closing means, and in the self-sustaining operation mode, the power that can be supplied from the solar cell. And a control unit that closes only a specific opening / closing unit to enable power supply only to a predetermined domestic load. 2. The control means closes only a specific opening / closing means to a predetermined domestic load when the power that can be supplied from the solar cell is equal to or less than a set value in the self-sustained operation mode. The solar power generation device according to claim 1, wherein only the electric power can be supplied. 3. The control means, in the self-sustaining operation mode, as the power that can be supplied from the solar cell decreases, the opening / closing means with the largest power consumption among the plurality of opening / closing means is sequentially opened to a predetermined level. The solar power generation device according to claim 1, wherein power can be supplied only to a domestic load.