KR20240088487A - Power Converting Apparatus - Google Patents

Abstract

The power conversion device according to an embodiment of the present invention includes a control unit that monitors the output signal of the photovoltaic power generation module input from the photovoltaic module, and the control unit varies the pulse width of the output signal of the photovoltaic module to Controls the power generation module.

Description

Power Converting Apparatus

The present invention relates to a power conversion device, and more specifically, to a power conversion device that controls a photovoltaic module and a photovoltaic power generation system.

Solar power generation is an eco-friendly energy generation method that is becoming widely used, replacing existing chemical or nuclear power generation. There are two types of solar power generation: stand-alone, where a battery is connected to a converter, and connected, which is connected to the power system. In general, stand-alone power generation consists of solar cells, storage batteries, power conversion devices, etc., and power grid-connected systems are connected to commercial power sources. It is configured to allow mutual exchange of power with the load system line.

Solar cell modules have different maximum generated power and operating points depending on the amount of sunlight and temperature. To operate solar cells at the maximum power point, MLPE is used to control the maximum power point (MPPT) on a module-by-module basis. However, in order to take stable action in an emergency situation, a separate signal transmission system must be established to control the photovoltaic module.

Registered Patent Publication No. 10-170008

The technical problem to be solved by the present invention is to provide a power conversion device and a photovoltaic power generation system that control a photovoltaic module.

In order to solve the above technical problem, the power conversion device according to an embodiment of the present invention includes a control unit that monitors the output signal of the photovoltaic module input from the photovoltaic module, and the control unit monitors the output signal of the photovoltaic module. The photovoltaic module is controlled by varying the pulse width.

Additionally, the output signal of the photovoltaic module may be the output current of the photovoltaic module.

In addition, the control unit may receive or block the output signal of the photovoltaic module to form a pulse, and may generate a control signal by varying the reception time or the blocking time.

Additionally, the output signal of the photovoltaic module may include the output voltage or output power of the photovoltaic module.

Additionally, the photovoltaic module includes a plurality of photovoltaic modules connected in series, and the control unit may stop or bypass the operation of at least one of the plurality of photovoltaic modules.

Additionally, the variable pulse width can be detected by the MLPE included in the photovoltaic module.

Additionally, the MLPE may include a current sensor that measures the output sensor.

Additionally, it may include an inverter that converts direct current input from the photovoltaic module into alternating current, and the control unit may be formed outside the inverter.

Additionally, the control unit may change the pulse width to stop the operation of the photovoltaic module when an RSD (Rapid Shut Down) situation occurs.

In order to solve the above technical problem, a photovoltaic power generation system according to an embodiment of the present invention includes at least one photovoltaic module; And a power conversion device that converts the output of the photovoltaic module and outputs it to a system or load, and the power conversion device controls the photovoltaic module by varying the pulse width of the output signal of the photovoltaic module.

According to embodiments of the present invention, MLPE can be controlled without a separate communication circuit. In addition, since MLPE control is possible only with current control, inverter MLPE is freely compatible.

Figure 1 is a block diagram of a power conversion device according to an embodiment of the present invention.
Figures 2 and 3 are block diagrams of a power conversion device according to a comparative example of the present invention.
Figure 4 is a block diagram of a power conversion device according to an embodiment of the present invention.
Figures 5 and 6 are diagrams for explaining a power conversion device according to an embodiment of the present invention.
Figure 7 is a block diagram of a photovoltaic power generation system according to an embodiment of the present invention.

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

However, the technical idea of the present invention is not limited to some of the described embodiments, but may be implemented in various different forms, and as long as it is within the scope of the technical idea of the present invention, one or more of the components may be optionally used between the embodiments. It can be used by combining or replacing.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless explicitly specifically defined and described, are generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as meaning, and the meaning of commonly used terms, such as terms defined in a dictionary, can be interpreted by considering the contextual meaning of the related technology.

Additionally, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In this specification, the singular may also include the plural unless specifically stated in the phrase, and when described as "at least one (or more than one) of A and B and C", it is combined with A, B, and C. It can contain one or more of all possible combinations.

Additionally, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and are not limited to the essence, sequence, or order of the component.

And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, that component is directly 'connected', 'coupled', or 'connected' to that other component. In addition to cases, it may also include cases where the component is 'connected', 'coupled', or 'connected' by another component between that component and that other component.

Additionally, when described as being formed or disposed “on top” or “bottom” of each component, “top” or “bottom” means that the two components are directly adjacent to each other. This includes not only the case of contact, but also the case where one or more other components are formed or disposed between the two components. In addition, when expressed as “top” or “bottom,” the meaning of not only the upward direction but also the downward direction can be included based on one component.

Modifications according to this embodiment may include some components of each embodiment and some components of other embodiments. That is, the modified example may include one of the various embodiments, but some components may be omitted and some components of other corresponding embodiments may be included. Or, it could be the other way around. Features, structures, effects, etc. to be described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be interpreted as included in the scope of the embodiments.

Figure 1 is a block diagram of a power conversion device according to an embodiment of the present invention, Figures 2 and 3 are block diagrams of a power conversion device according to a comparative example of the present invention, and Figure 4 is a block diagram of a power conversion device according to an embodiment of the present invention. It is a block diagram of a power conversion device according to an embodiment of the present invention, Figures 5 and 6 are diagrams for explaining a power conversion device according to an embodiment of the present invention, and Figure 7 is a block diagram of a photovoltaic power generation system according to an embodiment of the present invention. am.

The power conversion device 110 according to an embodiment of the present invention includes a control unit 114 that monitors the output signal of the photovoltaic module 120 input from the photovoltaic module 120. The control unit 114 controls the photovoltaic module 120 by varying the pulse width of the output signal of the photovoltaic module 120.

The power conversion device 110 according to an embodiment of the present invention may be an inverter. In a photovoltaic power generation system, it may be an inverter that receives voltage or current from the photovoltaic module 120 or MLPE 121 and converts it to the voltage required for the grid 130 or load 140.

The output of the photovoltaic module 120 may be input through the input unit 111. The input unit 111 receives the voltage generated by the photovoltaic module 120, or is connected to the MLPE 121 that optimizes the voltage of the photovoltaic module 120 and receives voltage from the MLPE 121. The maximum power point of the solar cell of the photovoltaic module 120 varies depending on the amount of sunlight, temperature, etc. To operate solar cells at their maximum power point, module-level power electronics (MLPE), which performs maximum power point tracking (MPPT) control on a module-by-module basis, can be used. The power conversion device connected to the photovoltaic module 120 equipped with the MLPE (121) receives voltage input through the MLPE (121).

The power conversion unit 112 converts the output signal of the photovoltaic module input to the input unit 111. The input signal is converted into a signal required by the system 130 or load 140. Here, the output signal of the photovoltaic module may be the output current, output voltage, or output power of the photovoltaic module. The power conversion unit 112 can convert the input voltage, which is the first direct current voltage, into the first alternating current voltage. Here, the first alternating current voltage may be the rated voltage of the system 130 or a voltage suitable for the load 140. Here, the load 140 may be a device that is driven using the voltage generated by the photovoltaic module. For example, it may be a building or a home device where photovoltaic modules are installed.

The power conversion unit 112 may include a DC-DC converter or inverter. The DC-DC converter can convert a first direct current signal into a second direct current signal. Here, the input signal input to the input unit 111 is a first direct current voltage, and the DC-DC converter can convert the first direct current voltage into a second direct current voltage. The first direct current voltage may vary depending on the power generation degree of the photovoltaic module 120 or may vary depending on tracking the maximum power point of the MLPE (121). The second direct current voltage may be the rated voltage of the system 130 or a voltage suitable for the load 140. Here, the load 140 may be a battery, and the second direct current voltage may be the rated voltage of the battery.

The inverter may convert the second direct current signal into a first alternating current signal. The inverter can convert the second direct current voltage whose voltage level is converted in the DC-DC converter unit into the first alternating current voltage according to the type of voltage of the system 130 so that it can be output to the system. Since the system 130 uses alternating current voltage, the direct current voltage must be output by changing the alternating voltage.

When a battery is connected between a DC-DC converter and an inverter, the battery is charged with the voltage generated by the DC-DC converter as well as a path that directly outputs the voltage generated by the DC-DC converter to the grid 130 through the inverter. And, when necessary, the inverter can convert the battery voltage and output it to the grid. This allows efficient power supply.

The output unit 113 may output the voltage converted in the power conversion unit 112 to the system 130 or the load 140. The output unit 113 includes a switching unit and can be connected to either the system 130 or the load 140 to output a signal converted by the power conversion unit 112.

The control unit 114 controls the photovoltaic module 120 by varying the pulse width of the output signal of the photovoltaic module 120. The control unit 114 can control the photovoltaic module 120 by varying the pulse width of the output signal of the photovoltaic module 120 without separate communication.

As shown in Figure 2 or Figure 3, a separate communication device may be required for communication. Figure 2 shows a method using PLC communication (power line communication), which includes a photovoltaic module (PV), an MLPE (including a DC-DC converter and a communication receiver) mounted on the photovoltaic module, and a signal transmitter and inverter for communication between power lines. It can be composed of: A separate device is required to transmit signals for communication.

Figure 3 shows a method using wireless communication, which consists of a photovoltaic module (PV), an MLPE (including a DC-DC converter and communication receiver) mounted on the photovoltaic module, and a wireless signal transmitter and inverter for communication between power lines. You can. This also requires a separate device to transmit signals for communication, and the operation can be controlled through signals from the transmitter. In this case, a separate communication circuit and signal transmission unit are added to control the MLPE, resulting in installation costs, reduced efficiency, and power quality problems.

The control unit 114 receives or blocks the output signal of the photovoltaic module 120 to form a pulse, and can generate a control signal by varying the reception time or the blocking time. The control unit 114 may generate a pulse 300 and control the pulse width, as shown in FIG. 5 . The control unit 114 receives or blocks the output signal of the photovoltaic module 120 to form a pulse 300, and can generate a control signal by varying the blocking time 310 or the reception time 320. . The blocking time 310 represents 0 and the reception time 320 represents 1, but can represent one signal value per unit time. For example, if the unit time is 1 second and a pulse is formed with a blocking time of 2 seconds and a receiving time of 3 seconds, a signal of 00111 may be displayed. In addition, various signals can be generated using variable pulse width. In addition to the pulse width, various signals can be generated by using changes in the size of the pulse or by using the width and size of the pulse.

The power conversion device 110 receives output from the photovoltaic module 120, and the photovoltaic module 120 can output power to the power conversion device 110 only when the power conversion device 110 and the power line are connected. . If the connection with the power conversion device 110 is interrupted, the output of the photovoltaic module 120 is blocked by the power conversion device 110. Using this point, the control unit 114 can generate a pulse (square wave) by repeatedly disconnecting and connecting with the photovoltaic module 120.

In this way, when the control unit 114 changes the width of the generated pulse, the output side of the photovoltaic module 120 may output a signal or be blocked. The photovoltaic module 120 can detect an output signal, detect a signal from the control unit 114, and operate accordingly.

The variable pulse width can be sensed by the MLPE 121 included in the photovoltaic module 120. MLPE 121 may include a current sensor that measures output current. The MLPE 121 may be connected to the photovoltaic module 120 and connected to the power conversion device 110. An input current sensor is connected to the photovoltaic module 120 and measures the input current input from the photovoltaic module 120, and is connected to the power conversion device 110 to measure the output current output from the power conversion device 110. It may include an output current sensor.

The photovoltaic module 120 includes a plurality of photovoltaic modules connected in series, and each photovoltaic module 120 may include an MLPE 121 . A plurality of photovoltaic modules are connected in an array form, and all MLPEs 121 forming the array are connected to an inverter, which is the power conversion device 110. The MLPE (121) current sensor is used to monitor input or output current information in real time, and in certain situations, the inverter can control the input current in the form of a square wave. The MLPE (121) monitors the width of the specified rectangular current wave and operates accordingly, enabling operation control such as stopping or bypassing the operation.

The control unit 114 may stop or bypass the operation of at least one of the plurality of photovoltaic modules. A plurality of photovoltaic modules 120 may be connected in series to receive the same control signal. Each of the plurality of photovoltaic modules 120 may be assigned an identification number, and the control unit 114 may vary the pulse width according to a signal identifying the identification number, thereby enabling operation control of only the corresponding photovoltaic module 120. there is.

As shown in FIG. 6, a plurality of photovoltaic modules 120 and the MLPEs 121 mounted on each may be connected in series to form an array. The inverter, which is the power conversion device 110, generates pulses and can control MLPE by varying the width of the pulse.

When a Rapid Shut Down (RSD) situation occurs, the control unit 114 can stop the operation of the photovoltaic module 120 by varying the pulse width. The control unit 114 monitors the photovoltaic module 120 and can stop the operation of the photovoltaic module 120 by varying the pulse width when an abnormal situation occurs. When an input signal within an abnormal range is input to the input unit 111, the control unit 114 operates and can quickly block the input signal. The input current or voltage input to the input unit 111 may be monitored, and if the range of the input signal is within the ideal range, the input may be discharged.

When an abnormality such as a fire occurs in the photovoltaic module 120, the level of the input current or voltage is lowered, and as a result, when an input current or input voltage within an abnormal range is input, the input of the photovoltaic module 120 can be blocked quickly. In the event of a fire, firefighters and other workers may approach the solar power panel, but the residual voltage is high, so there may be a risk of electric shock. The risk of electric shock can be eliminated by quickly lowering the residual voltage.

The control unit 114 may be formed outside the inverter 112 to convert direct current input from the photovoltaic module into alternating current. The control unit 114 may be formed in a backup box connected to an inverter or a DC-DC converter of a battery.

Figure 7 is a block diagram of a photovoltaic power generation system 200 according to an embodiment of the present invention. The detailed description of each component of the photovoltaic system 200 of FIG. 7 corresponds to the detailed description of the power conversion device of FIGS. 1 to 6, and redundant description will be omitted below.

The photovoltaic power generation system 200 according to an embodiment of the present invention includes at least one photovoltaic module 120 and a power conversion device that converts the output of the photovoltaic module 120 and outputs it to the system 130 or load 140. It includes 110, and the power conversion device 110 controls the photovoltaic module 120 by varying the pulse width of the output signal of the photovoltaic module 120.

It may include an MLPE 121 that optimizes the voltage of the photovoltaic module 120, and the input unit 111 is connected to the MLPE 121 to receive the input signal, and the power conversion module ( 110) may include a control unit 114 that controls the photovoltaic module 120 by varying the pulse width of the output signal of the photovoltaic module 120 according to the state of the input signal.

The control unit 114 may monitor the input current, and if the input current is lower or higher than the first voltage current, the control unit 114 may stop the operation of the photovoltaic module 120 and operate the voltage discharge unit.

The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

Those skilled in the art related to this embodiment will understand that the above-described base material can be implemented in a modified form without departing from the essential characteristics. Therefore, the disclosed methods should be considered from an explanatory rather than a restrictive perspective. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be construed as being included in the present invention.

Claims (10)

It includes a control unit that monitors the output signal of the photovoltaic module input from the photovoltaic module,
The control unit is a power conversion device that controls the photovoltaic module by varying the pulse width of the output signal of the photovoltaic module. According to paragraph 1,
A power conversion device in which the output signal of the photovoltaic power generation module is the output current of the photovoltaic power generation module. According to paragraph 1,
The control unit,
A power conversion device that receives or blocks the output signal of the photovoltaic module to form a pulse, and generates a control signal by varying the reception time or blocking time. According to paragraph 1,
A power conversion device wherein the output signal of the photovoltaic module includes the output voltage or output power of the photovoltaic module. According to paragraph 1,
The photovoltaic module includes a plurality of photovoltaic modules connected in series,
The control unit,
A power conversion device that stops or bypasses the operation of at least one of the plurality of photovoltaic modules. According to paragraph 1,
A power conversion device in which the variable pulse width is sensed by the MLPE included in the photovoltaic module. According to clause 6,
The MLPE is a power conversion device including a current sensor that measures the output sensor. According to paragraph 1,
It includes an inverter that converts direct current input from the photovoltaic module into alternating current,
The control unit is a power conversion device formed outside the inverter. According to paragraph 1,
The control unit,
A power conversion device that changes the pulse width to stop the operation of the photovoltaic module when an RSD (Rapid Shut Down) situation occurs. at least one photovoltaic module; and
It includes a power conversion device that converts the output of the photovoltaic module and outputs it to the system or load,
The power conversion device is,
A photovoltaic power generation system that controls the photovoltaic module by varying the pulse width of the output signal of the photovoltaic module.