KR20240014316A - Enhanced solar photovoltaic power generation system for blocking earth fault - Google Patents

Abstract

The present invention relates to a solar power generation system that is strong against ground faults. When the inverter input voltage is below the inverter operation voltage, the inverter input voltage is raised to the inverter start voltage range to start the inverter, thereby generating solar power generation while preventing ground faults. It is designed to be strong against blocking.

Description

{Enhanced solar photovoltaic power generation system for blocking earth fault}

The present invention relates to solar power generation technology, and particularly to a solar power generation system that is resistant to ground fault interruption.

A solar photovoltaic power generation system is a system that directly converts the sun's light energy into electrical energy using solar cells. It has the advantage of generating electricity semi-permanently without generating carbon dioxide during power generation. .

Figure 1 is a diagram illustrating a typical solar power generation system. As shown in FIG. 1, a typical solar power generation system 10 includes a plurality of solar strings 11, at least one inverter 12, and a plurality of connection panels 13.

A plurality of solar strings 11 convert sunlight into photoelectric power and output it as direct current power. The solar string 11 is made up of a plurality of solar panels connected in series, and each solar panel has a plurality of solar cells connected in series/parallel.

At least one inverter 12 converts the direct current power output and input from the plurality of solar strings 11 and outputs it into alternating current power. The AC power output from the inverter 12 is provided to the commercial power system 20 and supplied to loads (houses, buildings, power facilities such as buildings).

A plurality of connection panels 13 electrically connect the output terminal of each of the plurality of solar strings 11 to the input terminal of the inverter 120. A plurality of solar strings 11 may be connected in common to one inverter 12 in parallel through the connection panel 13, and a plurality of solar strings 11 may be connected to a plurality of inverters ( 12) can also be connected in series one-to-one.

Earth faults in which current flows from the solar power generation system 10 to the ground occur at the output terminal of the solar strings 11, the input terminal of the inverter 12, and the output terminal of the inverter 12. In the conventional case, the inverter 12 A current sensor 14 was installed on the output side to detect ground fault current, and when a ground fault occurred, the inverter 12 was cut off or the entire circuit was cut off.

When the inverter 12 is blocked or the entire circuit is blocked, the solar power generation operation of the solar power generation system 10 stops and electricity cannot be produced, and where in the solar power generation system 10 does the ground fault occur? Because it was unknown, there was the inconvenience of having to inspect the entire solar power generation system (10) to find out where the ground fault occurred.

Moreover, when a ground fault occurs at the output terminal of the solar string (11) and the input terminal of the inverter and the ground fault blocking device in the inverter operates, a high open voltage applied between the solar string (11) and the input terminal of the inverter (12) (when the inverter is blocked) Since the solar string output voltage was not dissipated, there was a risk of electric shock occurring when maintenance personnel inspected this part. In addition, there was a risk of fire due to the generation of high arc current when a full-scale secondary ground fault occurred following the primary ground fault before the ground fault operating current of the solar string.

On the other hand, if a ground fault occurs at the output terminal of the inverter 12, it must be blocked using the blocking device 21 of the commercial power system 20, but the blocking device 21 of the commercial power system 20 is not used in the solar power generation system 10. Since the maintenance personnel of ) could not operate it, cooperation from the manager of the commercial power system (20) was required, making response impossible or delayed.

On the other hand, when ground faults are blocked using the blocking device 21 of the commercial power system 20 with the cooperation of the commercial power system 20 manager, among the loads using commercial power (power facilities such as houses, buildings, buildings, etc.) There were concerns that some people might not receive power, causing damage to electricity consumers.

Therefore, when the inverter input voltage is lower than the inverter starting voltage, the present inventor is researching a solar power generation system that increases the inverter input voltage to the inverter starting voltage range to start the inverter to generate solar power generation and is also resistant to ground fault interruption. did.

Republic of Korea Patent No. 10-2283826 (announced on 2021.08.02)

The purpose of the present invention is to provide a solar power generation system that generates solar power by raising the inverter input voltage to the inverter starting voltage range to start the inverter when the inverter input voltage is lower than the inverter starting voltage, and is also resistant to ground fault interruption. Do it as

According to one aspect of the present invention for achieving the above object, a solar power generation system that is resistant to ground faults includes a plurality of solar strings that convert sunlight into photoelectric power and output direct current power; a single inverter that converts direct current power output and input from multiple solar strings and outputs it into alternating current power; a connection panel that electrically connects the output terminals of each of the plurality of photovoltaic strings to the single inverter input terminal in parallel; A first switch installed between a plurality of solar strings and a connection panel, connected to the (+) output terminal of each solar string, and a second switch connected to the (-) output terminal of each solar string, A matrix switch connected between the output terminals of two neighboring solar strings and including a third switch connected between the (-) output terminal of one solar string and the (+) output terminal of the other solar string; It includes a control unit that performs inverter starting and ground fault blocking functions through switch switching control of the matrix switch.

According to an additional aspect of the present invention, when the inverter input voltage is lower than the inverter operation voltage, the control unit turns on the second switch of one solar string and the first switch of the other solar string among the two neighboring solar strings. Turn off and turn on the third switch to control the switching of the matrix switch so that neighboring solar strings are connected in series with the inverter input terminal, thereby raising the inverter input voltage to the inverter starting voltage range to start the inverter. It can be implemented.

According to an additional aspect of the present invention, when the inverter input voltage is more than twice the rated operating voltage of the inverter while neighboring solar strings are connected in series with the inverter input terminal by the mattress switch, the control unit is in the off state. The second switch of one solar string and the first switch of the other solar string are turned on, and the third switch in the on state is turned off, so that the neighboring solar strings are connected to the inverter input terminal. By controlling the switch switching of the matrix switch so that it is connected in parallel, the inverter can be implemented to operate normally even if the solar strings return to the state of being connected in parallel with the inverter input terminal.

According to an additional aspect of the present invention, a solar power generation system resistant to ground fault is installed at the inverter output terminal, and further includes a first current sensor for detecting the inverter output terminal current, and the inverter output terminal ground fault current is detected by the first current sensor. When detected, the control unit turns off the first and second switches of each solar string and controls the switching of the matrix switch to block the output of all solar strings, thereby blocking the ground fault at the inverter output terminal. You can.

According to an additional aspect of the present invention, a solar power generation system resistant to ground faults is installed at the output terminal of each of the plurality of solar strings, and further includes a plurality of second current sensors that detect the solar string output terminal current, The ground fault current at the output terminal of a specific solar string is detected by the second current sensor, and when the solar strings are connected in parallel with the inverter input terminal, the control unit turns off only the first and second switches of the solar string for which the ground fault current was detected ( Off), it can be implemented to block ground faults at the output terminal of the solar string by controlling the switch switching of the matrix switch so that only the output of the solar string with a ground fault is blocked among the solar strings connected in parallel with the inverter input terminal.

According to an additional aspect of the present invention, the ground fault current of the solar string output terminal is detected by the second current sensor, and when the neighboring solar strings are connected in series with the inverter input terminal, the control unit is connected to the first switch in the ON state and Solar string output terminal by turning off at least one of the second switch and the third switch to control switch switching of the matrix switch to block the output of the solar strings when neighboring solar strings are connected in series with the inverter input terminal. It can be implemented to block ground faults.

According to an additional aspect of the present invention, the first switch, second switch, and third switch are implemented in a parallel structure of a relay switch, which is a mechanical contact switch, and an IGBT (Isolated Gate Bipolar Transistor) switch, which is a logical semiconductor switch. It can be.

In the present invention, when the inverter input voltage is below the inverter operating voltage, the inverter input voltage is raised to the inverter starting voltage range to start the inverter to generate solar power generation. At the same time, it is resistant to ground fault interruption, so stable solar power generation system operation is possible. There is a possible effect.

1 is a diagram illustrating a typical solar power generation system according to the present invention.
Figure 2 is a block diagram showing the configuration of an embodiment of a solar power generation system resistant to ground fault interruption according to the present invention.
Figure 3 is a circuit diagram showing the configuration of an embodiment of a solar power generation system resistant to ground fault interruption according to the present invention.
Figure 4 is a diagram illustrating the string output state when multiple neighboring solar strings are connected in series to the inverter input terminal by switching control of the matrix switch of the solar power generation system robust against ground fault interruption according to the present invention.
Figure 5 is a diagram illustrating the switching state of the matrix switch when a ground fault occurs at the output terminal of the inverter of the solar power generation system resistant to ground fault interruption according to the present invention.
Figure 6 is a diagram illustrating the switching state of the matrix switch when a ground fault occurs at the output terminal of a specific solar string while the solar strings of the solar power generation system resistant to ground fault interruption according to the present invention are connected in parallel with the inverter input terminal.
Figure 7 shows the matrix switch when a ground fault occurs at the output terminal of the solar string while multiple neighboring solar strings are connected in series to the inverter input terminal by switching control of the matrix switch of the solar power generation system resistant to ground fault interruption according to the present invention. This is a diagram illustrating the switching state of .
Figure 8 is a diagram illustrating a switch parallel structure of a solar power generation system resistant to ground fault interruption according to the present invention.

Hereinafter, the present invention will be described in detail through preferred embodiments described with reference to the attached drawings so that those skilled in the art can easily understand and reproduce it. Although specific embodiments are illustrated in the drawings and related detailed descriptions are described, they are not intended to limit the various embodiments of the present invention to any particular form.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the embodiments of the present invention, the detailed description will be omitted.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be.

On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

FIG. 2 is a block diagram showing the configuration of an embodiment of a solar power generation system resistant to ground fault interruption according to the present invention, and FIG. 3 is a circuit diagram showing the configuration of an embodiment of a solar power generation system resistant to ground fault interruption according to the present invention. am.

As shown in Figures 2 and 3, the solar power generation system 100 that is resistant to ground faults according to this embodiment includes a plurality of solar strings 110, a single inverter 120, and a connection panel ( 130), a matrix switch 140, and a control unit 150.

A plurality of solar strings 110 convert solar light into photoelectricity and output it as direct current power. The solar string 110 is made up of a plurality of solar panels connected in series, and each solar panel has a plurality of solar cells connected in series/parallel.

A single inverter 120 converts the direct current power output and input from the plurality of solar strings 110 and outputs it as alternating current power. The AC power output from the inverter 120 is provided to the commercial power system 200 and supplied to loads (houses, buildings, power facilities, etc.).

At this time, the inverter 120 may be implemented to provide stable AC power to the commercial power system 200 through maximum power tracking control (MPPT: Power Point Tracking). Solar power generation is sensitive to external conditions such as climate, solar radiation, and temperature, so the voltage and current output from the solar strings 110 change from time to time. It can provide alternating current power.

When the output terminal of the solar string 110 is open, that is, the resistance of the output terminal is infinite, an open voltage appears on both ends of the solar string 110, and since no current flows, the transmitted power (Power) is 0. This happens.

As the resistance of the output terminal of the solar string 110 gradually decreases, current flows through the resistance and power is transmitted. At this time, due to the nature of solar power generation, a lot of current flows and the voltage drops. When the resistance decreases beyond a certain point, the voltage drops, but there is a point where the current no longer increases.

Therefore, by appropriately adjusting the load according to external circumstances, the maximum current and voltage can be obtained, that is, the maximum power operating point (MPOP) at which the maximum power can be obtained, and the maximum power operating point (MPOP) is determined by external conditions. It varies depending on climate, solar radiation, temperature, etc. When the inverter 120 outputs AC power through maximum power tracking control (MPPT) that follows the maximum power operating point (MPOP), stable AC power can be provided to the commercial power system 200.

Meanwhile, the AC power output of the inverter 120 must be greater than commercial power. When the AC power output from the inverter 120 is less than commercial power, a phenomenon in which commercial power from the commercial power system 200 flows backwards toward the solar power generation system occurs. To prevent this, the input of the inverter 120 is turned off. It must be maintained above the voltage but below the maximum operating voltage for inverter output efficiency.

The connection panel 130 electrically connects the output terminal of each of the plurality of solar strings 110 to the input terminal of the single inverter 120 in parallel. For example, an even number of photovoltaic strings 110 may be electrically connected in common (parallel) to the input terminal of a single inverter 120 through the connection panel 130.

The matrix switch 140 is installed between a plurality of solar strings 110 and the connection panel 130, and includes first switches 141, second switches 142, and third switches 143. Includes.

The first switch 141 is connected to the (+) output terminal of each solar string 110. The second switch 142 is connected to the (-) output terminal of each solar string 110. The third switch 143 is connected between the output terminals of two neighboring solar strings 110, and is connected between the (-) output terminal of one solar string and the (+) output terminal of the other solar string.

Referring to FIG. 3, the first switch 141 and the second switch 142 connected to both output terminals of each of the solar strings 110 are turned on, and the output terminals of the two solar strings 110 are turned on. The third switch 143 connected between the two is turned off, and it can be seen that the output terminals of the solar strings 110 are connected in parallel to the input terminal of the inverter 120.

The control unit 150 starts the inverter 120 and performs a ground fault blocking function through switch control of the matrix switch 140. When the weather is cloudy before sunrise or after sunset, the output voltage of each solar string 110 drops, so the input voltage of the inverter 120 falls below the starting voltage and the inverter does not operate.

In the present invention, in a situation where the input voltage of the inverter 120 falls below the starting voltage and the inverter does not operate, the control unit 150 controls the switching of the switches of the matrix switch 140 to generate a solar string connected in parallel to the inverter 120 ( 110) are implemented to be connected in series with the inverter 120 to increase the input voltage of the inverter 120 to the inverter starting voltage range, so that the inverter can start and start or continue solar power generation.

In addition, in the present invention, when a ground fault current is detected at the inverter output terminal and the solar string output terminal, the control unit 150 controls the switching of the switches of the matrix switch 140 to block the inverter output or the output of the string output terminal where the ground fault occurs. This can protect the solar power generation system by blocking ground faults.

By implementing this, the present invention enables solar power generation by raising the inverter input voltage to the inverter starting voltage range to start the inverter when the inverter input voltage is lower than the inverter starting voltage. At the same time, it is resistant to ground fault interruption, so stable solar power is achieved. Optical power generation system operation is possible.

Meanwhile, according to an additional aspect of the invention, when the input voltage 120 of the inverter 120 is lower than the inverter operation voltage, the control unit 150 operates the second solar string of one of the two neighboring solar strings 110. Turn off the switch 142 and the first switch 141 of the other solar string, and turn on the third switch 143, so that the solar strings 110 are connected to the input terminal of the inverter 120. By controlling the switch switching of the matrix switch 140 so that it is connected in series, the input voltage of the inverter 120 can be raised to the inverter starting voltage range, thereby starting the inverter 120.

For example, the open-circuit voltage (voltage measured with the inverter disconnected and the output of each solar string open) of the solar strings 110 connected in parallel to the inverter 120 is usually 80% of the inverter input rated voltage. That's about it.

For example, in the present invention, when the open-circuit voltage of the solar strings 110 measured before sunrise or after sunset or in cloudy weather is about 65% of the inverter input rated voltage, the control unit 150 controls the two neighboring solar strings 110. A matrix switch to turn off the second switch 142 of one of the solar strings and the first switch 141 of the other solar string, and turn on the third switch 143. Controls the switch switching of (140).

Then, as shown in FIG. 4, neighboring solar strings 110 are connected in series with the input terminal of the inverter 120, and the output voltages of the solar strings 110 are added so that the input voltage of the inverter 120 is within the inverter starting voltage range. As it rises, the inverter 120 is started and solar power generation is achieved.

Figure 4 is a diagram illustrating the string output state when a plurality of neighboring solar strings are connected in series with a mattress switch by switching control of the matrix switch of the solar power generation system resistant to ground fault interruption according to the present invention.

Referring to FIG. 4, of the two neighboring solar strings 110, the second switch 142 of one solar string and the first switch 141 of the other solar string are turned off. , it can be seen that the third switch 143 is turned on and the neighboring solar strings 110 are connected in series with the input terminal of the inverter 120.

By implementing this, the present invention can generate solar power by raising the inverter input voltage to the inverter starting voltage range to start the inverter when the inverter input voltage is lower than the inverter starting voltage.

Meanwhile, according to an additional aspect of the invention, when the inverter input voltage is more than twice the inverter rated operating voltage while the solar strings 110 are connected in series, the control unit 150 operates one of the devices in the off state. The second switch 142 of the solar string and the first switch 141 of the other solar string are turned on, and the third switch 143 in the on state is turned off. By controlling the switch switching of the matrix switch 140 so that the optical strings 110 are connected in parallel with the input terminal of the inverter 120, the inverter operates normally even if the solar strings 110 return to the state of being connected in parallel with the input terminal of the inverter 120. It can be implemented to do so.

For example, when the solar strings 110 are connected in series to the inverter 120 before sunrise, the voltage of each of the solar strings 110 steadily increases and the voltage of each solar string 110 increases. The input voltage of the inverter 120, which is the sum of the output voltages, also increases.

When the input voltage of the inverter 120 increases and becomes more than twice the rated operating voltage of the inverter, the control unit 150 switches the second switch 142 of one solar string in the Off state and the second switch 142 of the other solar string. The switch switching of the matrix switch 140 is controlled to turn on the first switch 141 and turn off the third switch 143 in the on state. Then, as shown in FIG. 3, the solar strings 110 return to a state in which they are connected in parallel with the input terminal of the inverter 120, and solar power generation continues.

When the input voltage of the inverter 120 is more than twice the rated operating voltage of the inverter, the reason why the solar strings 110 are connected in parallel with the input terminal of the inverter 120 is that the input voltage of the inverter 120 is 2 times the rated operating voltage of the inverter. This is because when the solar strings 110 are connected in parallel with the input terminal of the inverter 120, the output voltage of the solar strings 110 becomes more than the inverter rated operating voltage and becomes greater than the inverter starting voltage.

By implementing it in this way, the present invention returns to the state where the solar strings 110 are connected in parallel with the input terminal of the inverter 120 when the inverter input voltage becomes greater than the inverter starting voltage, so that solar power generation continues, thereby ensuring stable solar power generation. This can be done.

Meanwhile, according to an additional aspect of the invention, the solar power generation system 100 that is resistant to ground fault interruption may further include a first current sensor 160. The first current sensor 160 is installed at the output terminal of the inverter 120 and detects the inverter output terminal current.

At this time, when a ground fault current at the output terminal of the inverter 120 is detected by the first current sensor 160, the control unit 150 turns on the first switch 141 and the second switch 142 of each of the solar strings 110. ) is turned off to block the ground fault at the inverter output terminal by controlling the switch switching of the matrix switch 140 to block the output of all solar strings 110.

Figure 5 is a diagram illustrating the switching state of the matrix switch when a ground fault occurs at the output terminal of the inverter of the solar power generation system resistant to ground fault interruption according to the present invention.

Referring to FIG. 5, when a ground fault current at the output terminal of the inverter 120 is detected by the first current sensor 160, the first switch 141 and the second switch 142 of each of the solar strings 110 is turned off, the output of all solar strings 110 is blocked, so no voltage is input to the input terminal of the inverter 120, and the ground fault of the inverter output terminal 120 is blocked, preventing danger at the input terminal and output terminal of the inverter 120. You can see it happening.

When implemented in this way, it is possible to respond to a ground fault at the inverter output terminal on the solar power generation system side without blocking the protection device of the commercial power system, thereby improving user convenience by eliminating the need for cooperation from the commercial power system.

Meanwhile, according to an additional aspect of the invention, the solar power generation system 100 that is resistant to ground fault interruption may further include a plurality of second current sensors 170. A plurality of second current sensors 170 are installed at the output terminal of each of the plurality of solar strings 110 and detect the output terminal current of the solar string 110.

For example, if a ground fault current occurs at the solar string output terminal by the plurality of second current sensors 170, a primary warning is first issued, and if the ground fault current continues to occur even after the primary warning, a secondary warning is provided at the solar string 110 output terminal as shown below. It may be implemented to perform a ground fault blocking operation.

If a ground fault current at the output terminal of a specific solar string is detected by the second current sensor 170, and the solar strings 110 are connected in parallel with the input terminal of the inverter 120, the control unit 150 detects the ground fault current. Only the first switch 141 and the second switch 142 of the solar string are turned off to block only the output of the solar string with a ground fault among the solar strings 110 connected in parallel with the input terminal of the inverter 120. It can be implemented to block ground faults at the output terminal of the solar string 110 by controlling the switch switching of the matrix switch 140 as much as possible.

Figure 6 is a diagram illustrating the switching state of the matrix switch when a ground fault occurs at the output terminal of a specific solar string while the solar strings of the solar power generation system resistant to ground fault interruption according to the present invention are connected in parallel with the inverter input terminal.

Referring to FIG. 6, while the solar strings 110 are connected in parallel with the input terminal of the inverter 120, a second current sensor ( When a ground fault current at the solar string output terminal is detected by 170), only the first switch 141 and the second switch 142 connected to the solar string output terminal where the ground fault current was detected are turned off, and the ground fault is The first switch 141 and the second switch 142, which are connected to the output terminal of another solar string that has not occurred, are turned on, and a ground fault occurs among the solar strings 110 connected in parallel with the input terminal of the inverter 120. It can be seen that the ground fault of the solar string where the ground fault occurred is blocked by only blocking the output of the solar string where the ground fault occurred.

When implemented in this way, only the solar string where the ground fault occurred can be detected and the ground fault can be blocked, making it easier to quickly identify and respond to the cause of the ground fault accident. By blocking the solar string output terminal that outputs direct current power, the high voltage that is not allowed between the connection panel and the inverter input terminal is reduced. Since the open-circuit voltage can be dissipated, the range of electric shock is narrowed.

Meanwhile, according to an additional aspect of the invention, the ground fault current at the output terminal of the solar string 110 is detected by the second current sensor 170, and when the solar strings 110 are connected in series with the input terminal of the inverter 120, the control unit Solar power connected in series with the input terminal of the inverter 120 by turning off at least one of the first switch 141, the second switch 142, and the third switch 143, which (150) is in the ON state. It may be implemented to block a ground fault at the output terminal of the solar string 110 by controlling switch switching of the matrix switch 140 to block the output of the strings.

Figure 7 shows the matrix switch when a ground fault occurs at the output terminal of the solar string while multiple neighboring solar strings are connected in series to the inverter input terminal by switching control of the matrix switch of the solar power generation system resistant to ground fault interruption according to the present invention. This is a diagram illustrating the switching state of .

Referring to FIG. 7, while the solar strings 110 are connected in series with the input terminal of the inverter 120, at least one of the second current sensors 170 installed at the output terminal of each of the solar strings 110 When a ground fault current at the solar string output terminal is detected, the third switch 143 is turned off to block the output terminal of the solar strings 110, thereby blocking the ground fault at the solar string output terminal. At this time, the first switch 141 and/or the second switch 142 may be turned off instead of the third switch 143.

Meanwhile, according to an additional aspect of the invention, the first switch 141, the second switch 142, and the third switch 143 are mechanical contact switches, such as relay switches 141a, 142a, and 143a. Wow, IGBT (Isolated Gate Bipolar Transistor) switches, which are logical semiconductor switches, can be implemented in a parallel structure (141b) (142b) (143b).

Figure 8 is a diagram illustrating a switch parallel structure of a solar power generation system resistant to ground fault interruption according to the present invention. Referring to Figure 8, relay switches (141a) (142a) (143a) with less thermal damage and IGBT switches (141b) (142b) (143b) with less contact damage due to excessive voltage are connected in parallel. By implementing the first switch 141, the second switch 142, and the third switch 143, the first switch 141, the second switch 142, and the third switch have the advantages of both a relay switch and an IGBT switch. It can be seen that 3 switches 143 are implemented.

When the first switch 141, the second switch 142, and the third switch 143 are turned on, the IGBT switches 141b, 142b, and 143b, which generate very small transient voltages and do not cause contact damage, are first turned on. After turning it on, the relay switches 141a, 142a, and 143a, which are less prone to thermal damage, are turned on, and then the IGBT switches, 141b, 142b, and 143b, which are less prone to thermal damage, are turned off. By doing so, the first switch 141, the second switch 142, and the third switch 143 have the advantages of a relay switch and an IGBT switch at the same time.

On the other hand, when the first switch 141, the second switch 142, and the third switch 143 are turned off, the transient voltage generation is very small, so the IGBT switches 141b, 142b, and 143b are used without contact damage. After turning on, turn off the relay switches 141a, 142a, and 143a, which are less prone to thermal damage, and then turn off the IGBT switches 141b, 142b, and 143b, which are less prone to thermal damage. ), the first switch 141, the second switch 142, and the third switch 143 have the advantages of a relay switch and an IGBT switch at the same time.

As described above, the present invention, when the inverter input voltage is below the inverter operating voltage, raises the inverter input voltage to the inverter starting voltage range to start the inverter to generate solar power generation, and is also resistant to ground fault interruption, thereby providing stable solar power. Optical power generation system operation is possible.

The various embodiments disclosed in this specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the various embodiments of the present invention.

Accordingly, the scope of the various embodiments of the present invention includes all changes or modified forms derived based on the technical idea of the various embodiments of the present invention in addition to the embodiments described herein. It should be interpreted as being

The present invention can be used industrially in the field of solar power generation technology and its application technology.

100: solar power generation system
110: solar string
120: inverter
130: Connection board
140: matrix switch
141: first switch
142: second switch
143: 3rd switch
150: control unit
160: first current sensor
170: Second current sensor
200: Commercial power system

Claims (7)

A plurality of solar strings that convert sunlight into photoelectric power and output direct current power;
a single inverter that converts direct current power output and input from multiple solar strings and outputs it into alternating current power;
a connection panel that electrically connects the output terminals of each of the plurality of photovoltaic strings to the single inverter input terminal in parallel;
A first switch installed between a plurality of solar strings and a connection panel, connected to the (+) output terminal of each solar string, and a second switch connected to the (-) output terminal of each solar string, A matrix switch connected between the output terminals of two neighboring solar strings and including a third switch connected between the (-) output terminal of one solar string and the (+) output terminal of the other solar string;
A control unit that performs inverter starting and ground fault blocking functions through switch control of the matrix switch;
A solar power generation system that is resistant to ground faults, including: According to claim 1,
Control section:
When the inverter input voltage is below the inverter operating voltage, the second switch of one solar string and the first switch of the other solar string among the two neighboring solar strings are turned off, and the third switch is turned on. A solar power generation system that is resistant to ground faults that raises the inverter input voltage to the inverter starting voltage range and starts the inverter by turning it on and controlling the switching of the matrix switch so that neighboring solar strings are connected in series with the inverter input terminal. According to claim 2,
Control section:
When neighboring solar strings are connected in series with the inverter input terminal by a mattress switch and the inverter input voltage is more than twice the inverter's rated operating voltage, the second switch of one solar string in the off state and the other switch Turn on the first switch of one solar string and turn off the third switch in the On state to control switch switching of the matrix switch so that neighboring solar strings are connected in parallel with the inverter input terminal. This is a solar power generation system that is resistant to ground faults, allowing the inverter to operate normally even if the solar strings return to being connected in parallel with the inverter input terminal. According to claim 3,
A solar power generation system that is resistant to ground faults:
A first current sensor installed at the inverter output terminal to detect the inverter output terminal current;
Contains more,
When a ground fault current at the inverter output terminal is detected by the first current sensor, the control unit turns off the first and second switches of each solar string and switches the matrix switch to block the output of all solar strings. A solar power generation system that is resistant to ground faults by controlling ground faults at the inverter output stage. According to claim 4,
A solar power generation system that is resistant to ground faults:
A plurality of second current sensors installed at the output terminal of each of the plurality of solar strings to detect the current of the solar string output terminal;
Contains more,
The ground fault current at the output terminal of a specific solar string is detected by the second current sensor, and when the solar strings are connected in parallel with the inverter input terminal, the control unit turns off only the first and second switches of the solar string for which the ground fault current was detected ( A solar power generation system that is resistant to ground faults, blocking ground faults in the solar string output terminal by controlling the switching of the matrix switch so that only the output of the solar string that has a ground fault is blocked among the solar strings connected in parallel with the inverter input terminal. According to claim 5,
When the ground fault current of the solar string output terminal is detected by the second current sensor, and the neighboring solar strings are connected in series with the inverter input terminal, at least one of the first switch, the second switch, and the third switch in the ON state of the control unit A solar system that is strong against ground faults blocks ground faults in the output terminal of solar strings by controlling the switching of the matrix switch to block the output of neighboring solar strings when they are connected in series with the inverter input terminal by turning one off. photovoltaic system. The method according to any one of claims 1 to 6,
The first switch, second switch, and third switch are:
A solar power generation system that is strong against ground faults implemented in parallel with a relay switch, a mechanical contact switch, and an IGBT (Isolated Gate Bipolar Transistor) switch, a logical semiconductor switch.