KR101445711B1 - Solar power system. - Google Patents

Abstract

The present invention relates to a solar power generation system and, more particularly, to a solar power generation system which determines weather conditions and a system failure through a pattern of a value (a string output value or a sensed value of an environment sensor) obtained by monitoring a situation of a solar power generation site, to convert a mode into any one of a string type mode, a parallel type mode and a sub array type mode so that an optimal inverter efficiency is induced for each situation.

Description

Solar power system.

[0001] The present invention relates to a solar power generation system, and more particularly, to a solar power generation system, in which a weather condition and a system failure are determined through a pattern of monitored values of a solar power generation site (a string output value or an environmental sensor sensing value) , A parallel type mode, and a sub-array type mode to thereby derive an optimal inverter efficiency for each situation.

In general, solar cells convert sunlight energy into electrical energy, which uses two types of semiconductors, p-type and n-type, to generate electricity.

When the light is irradiated to the solar cell, electrons and holes are generated inside, and the generated charges move to the P and N poles, and a potential difference is generated between the P and N poles by this phenomenon.

At this time, when a load is connected to the anode of the solar cell, current flows.

These solar cells can be connected to each other in series and in parallel, and can be used in a structure that can withstand natural environments and certain external impacts. Here, the solar cell is the minimum unit for generating electricity, and the solar cell module is the minimum As a unit, a plurality of solar cells are connected in series and in parallel, and they are generally used in a standardized manner.

Recently, due to the regulations, etc. related to the oil prices and the environment, despite the economy by excessive initial investment in the development of relying on fossil fuels so many restrictions on existing generator is relatively low, and domain for the conservation of the CO ₂ reduction Global efforts to expand and disseminate renewable energy such as solar and wind power are increasing.

The solar power generation system described above will be described in more detail. The solar power module converts and supplies DC power to usable AC power. In order to derive the maximum conversion efficiency according to the local environment characteristics, various strings This is possible.

Various attempts have been made to construct a string and multiple inverters to increase the system efficiency and simplify the circuit in accordance with the technology trend and the inverter price decrease. As shown in FIG. 1, as shown in FIG. 1, A method of constituting a circuit is derived.

As shown in FIG. 1, the string suitable for the environment (weather) and the circuit configuration method of the inverter are divided into a centralized type, a sub-array type, a parallel type, and a string type configuration method. However, it is impossible to provide the above-described configuration method at the same time.

Therefore, it is necessary to preliminarily review the configuration method that best suits the situation in accordance with the site situation, and in some way, there is a problem that the time and cost required for re-operation after the installation of the system is additionally required.

In order to solve the above problem, the micro-inverter type circuit configuration method can directly operate the micro-inverter connected to the solar cell module without string generation, and can operate independently, and has high efficiency and freedom of configuration. However, There arises a problem that it is difficult to secure.

Accordingly, in the present invention, as a next generation solar power generation technology that simultaneously satisfies the system efficiency and economical efficiency, it is possible to provide a solar power generation system that can monitor the solar power generation site conditions (the string output value or the sensing value of the environmental sensor) The present invention proposes a technique for judging a failure and switching to a mode of a string type mode, a parallel type mode or a subarray type mode to thereby derive the maximum inverter efficiency for each situation.

Korean Patent Publication No. 10-2013-0130186 (Feb.

SUMMARY OF THE INVENTION An object of the present invention to solve the above problems is to determine a weather condition and a system malfunction through a pattern of a monitoring value of a solar power generation site (a string output value or a sensing value of an environmental sensor) Mode or a sub-array type mode, thereby maximizing inverter conversion efficiency for each situation.

SUMMARY OF THE INVENTION [0006] The present invention provides a solution for achieving the above object.

That is, a string part 100 composed of a plurality of strings composed of a plurality of solar cell modules 110;

A first switch unit 200 including at least one switch 210a to 210n for electrically connecting or disconnecting each string according to an on / off signal of the mode variable control means;

A second switch unit 300 including one or more switches 310a to 310n for providing or disconnecting generated power provided from each string to the respective inverters in accordance with on / off signals of the mode variable control means, ;

An inverter unit 700 comprising a plurality of inverters for converting generated power provided from the string unit into AC power and supplying the AC power to a power system or a load;

By monitoring the ammeter and the voltmeter installed in each string of the string part, the standard deviation value and the average value are calculated with the power value of each string calculated, and the representative value is designated as a representative value of the current power generation status, And the sub-array type mode, and the average threshold value of the string power to determine the optimal mode of the present solar power generation site situation, And a mode variable control unit 500 for providing an on / off signal for each switch of the first switch unit and providing an on / off signal for each switch constituting the second switch unit to vary the mode.

The object of the present invention can be solved by the above configuration.

The present invention has the following effects.

According to the solar power generation system of the present invention, it is possible to determine a weather condition and a system malfunction through a pattern of monitoring values of a solar power generation site (a string output value or a sensing value of an environmental sensor) And the sub-array type mode, thereby exhibiting the effect of inducing the maximum inverter conversion efficiency for each situation.

Figure 1 is a diagram illustrating the advantages of various string-inverter configuration schemes.
2 is a schematic diagram of mode-variable operation of a solar power generation system according to an embodiment of the present invention.
FIG. 3 is an overall configuration view of a photovoltaic power generation system according to an embodiment of the present invention; FIG.
4 is a block diagram of a mode variable control means of a solar power generation system according to an embodiment of the present invention.
FIG. 5 is a view showing a mode classification according to representative values of a solar power generation site in a solar power generation system according to an embodiment of the present invention. FIG.
FIG. 6 is an exemplary view showing a decision criterion variable of mode selection of a solar power generation system according to an embodiment of the present invention; FIG.
FIG. 7 is a switch connection diagram in the case of the sub-array type mode of the photovoltaic power generation system according to the embodiment of the present invention, FIG. 8 is a switch connection diagram in the case of the string type mode, Switch connection diagram.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

It should be understood, however, that the scope of the present invention is not limited to these embodiments, and all of the technical ideas that fall within the scope of the present invention are within the scope of the present invention.

2 is a schematic diagram of a mode-variable operation of the solar power generation system according to an embodiment of the present invention.

As shown in FIG. 2, the system of the present invention is configured to switch to an optimum mode according to a change in power generation amount due to an environmental change, and operates by connecting a plurality of inverters variably.

This is performed by the mode switching processing unit, thereby achieving an effect of increasing the power generation efficiency, extending the life of the inverter, and promptly coping with the failure.

As shown in FIGS. 7 to 9, for example, the string type system is a sunny state, and the maximum output string is divided into individual inverters, such as a weather condition, a blur / rain, a partial shade, And the parallel type method performs a low output string as a blurred state or a low output string through a centralized inverter control and the subarray type method performs a partially low output string through a divided inverter control as a partial shadow state, In the event of a solar module / inverter failure, the faulty string and the inverter will be shut down.

By switching to the optimal mode according to various situations as described above, the efficiency of the entire system can be improved by inducing the maximum inverter efficiency for each situation.

3 is an overall configuration diagram of a solar power generation system according to an embodiment of the present invention.

3, the solar power generation system includes a string part 100 composed of a plurality of strings, a first switch part 200, a second switch part 300, a mode variable type control part 500, And an inverter unit 700 configured as an inverter.

The string unit 100 includes a plurality of strings (1 to n) of solar cell modules 110 and is connected to an inverter unit including a plurality of inverters.

For example, the first string is connected to the first inverter and the second string is connected to the second inverter.

At this time, in the case of the present invention, the switch portions are controlled on / off by the mode variable control means.

The first switch unit 200 includes one or more switches 210a to 210n for electrically connecting or disconnecting the respective strings according to on / off signals of the mode variable control unit.

That is, the connection or blocking between one string and another string is performed, and the string parts have a parallel connection configuration as shown in FIG.

The second switch unit 300 includes one or more switches 310a to 310n for providing or blocking the generated power provided from each string to the respective inverters in accordance with on / off signals of the mode variable control means .

That is, it is provided between the string part and the inverter part to perform power supply or cutoff by on / off, and has a serial connection configuration between the string part and the inverter part as shown in FIG.

The inverter unit 700 includes a plurality of inverters, converts generated power provided from each string to AC power, and supplies the AC power to a power system or a load.

At this time, an ammeter and a voltmeter installed in each string of the string are monitored through the mode variable control unit 500, which is a core configuration of the present invention, and the standard deviation value and the average value are calculated with the power values of the calculated strings, And compares the representative value with an average threshold value of the string power and a standard deviation threshold value of the string power for switching to the mode of the string type mode, the parallel type mode, or the subarray type mode set in advance.

Thereafter, an on / off signal is provided for each of the switches constituting the first switch unit by determining a mode corresponding to the current state of the PV system, and an on / off signal is provided for each switch constituting the second switch unit Thereby changing the mode.

For example, the on / off control of the first switch unit and the second switch unit is performed so as to change to the string-type mode when the weather is clear after the sub-array type operation.

4 is a block diagram of a mode variable control means of a solar power generation system according to an embodiment of the present invention.

4, the mode variable control unit 500 of the present invention includes a monitoring unit 510, a database unit 520, a current situation determination unit 530, and a mode switching unit 540 .

The monitoring unit 510 monitors the ammeter and the voltmeter installed in each string of the string and calculates the standard deviation value and the average value of the calculated power value of each string and designates the standard deviation value and the average value as a representative value of the solar power generation site situation, .

FIG. 5 shows a mode classification chart according to representative values of the PV power generation site as described above. Referring to FIG. 5, A mode is a mode in which a string type configuration (string output normal, weather clear) B mode is defined as a parallel type (string output normal, weather fog), which is defined as a parallel mode, and C mode is a sub-array type (string output Abnormal, shadow or string failure), which is defined as a sub-array type mode.

The mode variable control means determines a weather condition and a system malfunction through a pattern of a monitoring value of a solar power generation site (a string output value or a sensing value of an environmental sensor) It is to distinguish the situation on the spot by the mode.

At this time, if the string power standard deviation is high, it will be converted to the C mode. If the string power standard deviation is low, the string power average value is determined. If the average value is high, the A mode will be converted. Will be.

The database unit 520 stores a standard deviation threshold value of a string power for switching to a mode of a string type mode, a parallel type mode, or a sub-array type mode, an average threshold value of the string power, The standard deviation value and the average value of the string power are stored.

At this time, the current situation determination unit 530 extracts the standard deviation value information from the database unit, compares the standard deviation value information with the extracted standard deviation value information to determine the normal / abnormal string output, and if it is an abnormal string output The sub-array type mode (C mode) is selected.

If the average value information is higher than the average threshold value, the string type mode is selected. If the average value information is higher than the average threshold value, the parallel type mode is selected The mode switching processor provides the selected mode information.

Finally, when the mode provided by the current situation determination unit is a sub-array type mode, the mode switching processor 540 divides the upper group and the lower group according to the string power state, and independently configures a string type mode or a parallel type mode Off signal for each of the switches constituting the first switch unit and the second switch unit.

On the other hand, in the case of the string type mode, each inverter unit provides an ON signal for each switch constituting the first switch unit and the second switch unit so that MPPT control can be independently performed. In the case of the parallel mode, Off signal for each of the switches constituting the first switch unit and the second switch unit so as to be sequentially operated from the inverter unit having a small usage amount in accordance with the situation.

Hereinafter, the functions of the above components will be described in detail.

The monitoring unit 510 includes at least one of a representative value designating module 511 and an external environment information processing module 512.

The representative value designation module 511 monitors the ammeter and the voltmeter installed in each string of the string portion to obtain the power value of each calculated string and calculates the standard deviation value and the average value in real time to calculate a representative value .

For example, the first current situation representative value is designated as the string power standard deviation value, the second current situation representative value is designated as the string power mean value, and the development status of the current string section classified as shown in FIG. 5 is determined, Mode.

The external environment information processing module 512 acquires sensor values measured from external environmental sensors and stores them in the database unit.

The database unit 520 includes at least one of a standard deviation threshold derivation module 521, an average threshold derivation module 522, and a database module 523.

The standard deviation threshold derivation module 521 calculates a string power standard deviation threshold value for determining whether the string output is normal through the power conversion efficiency information of the string type mode, the parallel type mode and the subarray type mode according to the string power standard deviation value However,

The average threshold value derivation module 522 derives the string power average threshold by determining the strength of the string output based on the power conversion efficiency information of the string type mode and the parallel type mode with respect to the string power mean value.

At this time, the database module 523 stores the string power standard deviation threshold value derived by the standard deviation threshold value deriving unit, the string power standard deviation threshold value derived from the average threshold value deriving unit, the external environment information, And stores the average value of the deviation value and the string power.

As shown in FIG. 6, the criterion for determining whether the string output is normal is the string power standard deviation threshold, and the criterion for determining the strength of the string output is the string power average threshold value.

Therefore, the standard deviation threshold value derivation module can calculate the standard deviation threshold value of the string power standard deviation threshold value for determining whether the string output is normal through the system power conversion efficiency of each mode (A mode, B mode, C mode) And stores it in the database module.

The average threshold value derivation module previously determines the strength of the string output through the system power conversion efficiency of each mode (A mode and B mode) of the string power average, and derives the string power average threshold value and stores it in the database module do.

The current situation determination unit 530 includes a standard deviation comparison determination module 531, an average comparison determination module 532, and a selection mode information provision module 533. [

The standard deviation comparison determination module 531 extracts standard deviation value information from the database unit, compares the standard deviation value information with the standard deviation value information to determine a normal / abnormal string output, and outputs a normal / Mode (C mode).

If the average value information is higher than the average threshold value, the average comparison determination module 532 extracts the average value information from the database unit in the case of the normal string output as a result of the determination by the standard deviation comparison determination module, Mode (A mode) is selected, and when it is lower, the parallel mode (B mode) is selected.

At this time, the selection mode information providing module 533 acquires mode information selected from any one of the standard deviation comparison determination module and the average comparison determination module, and provides the selected mode information to the mode switching processor to perform the switching operation will be.

In summary, the representative value calculated through monitoring is compared with the threshold value set for each mode switching to determine the optimal mode of the present solar power generation site situation.

Specifically, a normal / abnormal string output is determined by first comparing the string power standard deviation value with a threshold value. In case of an abnormal state, the C mode is selected. In the normal case, the string output power average value is compared with a threshold value, And selects the A mode or the B mode.

In the A mode, the string output will be normal and the weather will be in the clear. In the B mode, the string output will be normal and the weather will be in the blur. In the C mode, the string output is abnormal, .

The mode switching processor 540 includes a subarray type mode switching processing module 541, a string type mode switching processing module 542, and a parallel type mode switching processing module 543.

That is, as shown in FIG. 7, the sub-array type mode switching processing module 541 determines whether the sub-array type mode switching processing module 541 is in a sub-array type mode (C mode) Off signal for each of the switches constituting the first switch unit and the second switch unit, respectively, in order to independently configure a string type mode or a parallel type mode.

For example, the upper group is connected to the string units # 1 and # 2 by the inverter unit # 1. To do this, the 10 switch on signal, the A switch on signal, and the B switch off signal are provided, And is driven.

In addition, an OFF signal is given to the 20 switches to divide the upper group and the lower group and perform the operation independently of each other.

In order to do this, 30, 40, and 50 switch-off signals, and C, D, E, and F switch-on signals are provided to the inverter units # 3 to # , Which is operated in a string-type mode.

8, when the mode provided by the current situation determiner is a string type mode (A mode), each of the inverter units independently performs MPPT control The ON signal is provided for each of the switches constituting the first switch unit and the second switch unit.

For example, it provides 10 to 50 switch-off signals, A to F switch-on signals, and configures the circuit in a string-like manner so that each inverter can independently perform MPPT control.

On the other hand, the parallel type mode switching processing module 543 may be configured such that, as shown in FIG. 9, when the mode provided by the current situation determination unit is a parallel type (B mode) Off signal for each of the switches constituting the first switch unit and the second switch unit to be sequentially operated.

For example, 10 to 50 switch-on signals, A to D switch-on signals, and E to F switch-off signals.

The number of string portions and inverter portions shown in FIGS. 7 to 9 is merely an example, and it is natural that the number of the string portions and the inverter portions can be reduced or increased according to the field situation.

If it is configured as described above, the string type mode is most effective when it is clear, the parallel type mode is most effective when it is blurred, and the sub-array type mode is most effective when the shadow is broken or broken, The mode is switched to the optimum mode.

As a result, if the configuration and operation are performed as described above, the optimal inverter conversion efficiency can be derived according to the weather condition and the fault condition through the variable mode construction and the contextual control.

Specifically, the inverter conversion efficiency can be improved by varying the mode of the string type mode, the parallel type mode, or the sub-array type mode by controlling the first switch unit and the second switch unit according to the weather conditions.

In addition, it is possible to provide a power generating effect even if a failure occurs in any of the inverter units, and it is possible to selectively drive the inverter units according to the cumulative power amount of the plurality of inverter units, thereby limiting unnecessary drive of the inverter unit, But also to synergies that extend the life of the wealth.

Although the embodiment of the photovoltaic generation system to which the technical idea of the present invention is applied has been described, there can be various modified inventions having the same technical idea, and it is also obvious that the scope of the invention is also within the scope of the present invention.

100: string portion
200: first switch section
300: second switch section
500: mode variable type control means
700: Inverter section

Claims (7)

In a solar power generation system,
A string part 100 composed of a plurality of strings constituted by a plurality of solar cell modules 110;
A first switch unit 200 including at least one switch 210a to 210n for electrically connecting or disconnecting each string according to an on / off signal of the mode variable control means;
A second switch unit 300 including one or more switches 310a to 310n for providing or disconnecting generated power provided from each string to the respective inverters in accordance with on / off signals of the mode variable control means, ;
An inverter unit 700 comprising a plurality of inverters for converting generated power provided from the string unit into AC power and supplying the AC power to a power system or a load;
A monitoring unit for monitoring the ammeter and voltmeter installed in each string of the string and calculating the standard deviation value and the average value of the calculated power value of each string, designating the calculated standard deviation value as a representative value of the PV power site situation, 510),
The standard deviation value of the string power for switching to any one of the string type mode, the parallel type mode and the sub-array type mode, the average threshold value of the string power, the external environment information, the standard deviation value of the string power, A database unit 520 storing an average value,
An output unit for outputting the standard deviation value information from the database unit, and comparing the standard deviation value information with the standard deviation threshold value information to determine a normal / abnormal string output and selecting a subarray type mode when the output is an abnormal string, And selects a string type mode if the average value information is higher than the average threshold value and selects the parallel type mode when the average value information is lower than the average threshold value to determine the current situation to provide mode information selected by the mode switching processor 530,
In the case where the mode provided by the current situation determination unit is a sub-array type mode, in order to configure a string type mode or a parallel type mode independently of the upper group and the lower group according to the string power status, Off signal for each of the switches constituting the switch unit and for each switch constituting the first switch unit and the second switch unit so that each inverter unit can independently perform the MPPT control in the case of the string type mode, Off signal for each of the switches constituting the first switch unit and the second switch unit in order to sequentially operate the inverter unit in which the amount of usage is small in accordance with the string power situation in the parallel mode, And a mode switching processing unit 540. The variable mode control unit 500 includes: PV systems that.
delete The method according to claim 1,
The monitoring unit 510,
A representative value assigning module 511 for acquiring the power value of each string calculated by monitoring the ammeter and the voltmeter installed in each string of the string, calculating a standard deviation value and an average value, and designating the standard deviation value and the average value as a representative value,
And an external environment information processing module (512) for acquiring sensor values measured from external environmental sensors and storing them in a database unit.
The method according to claim 1,
The database unit 520,
A standard deviation threshold derivation module 521 for deriving a string power standard deviation threshold value for determining whether the string output is normal through the power conversion efficiency information of the string power standard deviation string type mode, the parallel type mode and the subarray type mode, ,
An average threshold derivation module 522 for deriving a string power average threshold value by determining the strength of the string output through the power conversion efficiency information of the string power average average string type mode and the parallel type modes,
And stores the average value of the string power standard deviation value and string power standard deviation value derived from the string power standard deviation threshold derived from the standard deviation threshold deriving unit and the string power standard deviation threshold derived from the average threshold value deriving unit, And a database module (523) which is connected to the network.
The method according to claim 1,
The current situation determination unit 530,
A standard deviation comparison judgment module 531 for comparing the standard deviation value information with the standard deviation threshold value information to determine a normal / abnormal string output and selecting a sub-array type mode when the abnormal string output is an abnormal string output,
If the average value information is higher than the average threshold value, the string type mode is selected. If the average value information is lower than the average threshold value, An average comparison determination module 532 for selecting the type mode,
And a selection mode information providing module 533 for acquiring mode information selected from any one of the standard deviation comparison determination module and the average comparison determination module and providing the mode information selected by the mode switching processor. Solar power generation system.
The method according to claim 1,
The mode switching processing unit 540,
In the case where the mode provided by the current situation determination unit is a sub-array type mode, in order to configure a string type mode or a parallel type mode independently of the upper group and the lower group according to the string power situation, A sub-array type mode switching processing module 541 for providing an on / off signal for each of the switches constituting the unit,
A string for providing an ON signal for each switch constituting the first switch unit and the second switch unit so that each inverter unit can independently perform the MPPT control when the mode provided by the current situation determining unit is a string- Type mode switching processing module 542,
Off signal for each switch constituting the first switch unit and the second switch unit to be sequentially operated from the inverter unit having a small usage amount when the mode provided by the current situation determination unit is the parallel mode, And a mode switching processing module (543).
The method according to claim 1,
The mode variable control means (500)
Wherein the inverter conversion efficiency is improved by varying the mode of the string type mode, the parallel type mode, and the subarray type mode by controlling the first switch unit and the second switch unit for each weather condition.

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