Device for performing safety functions and solar power generation system including the same

Abstract

According to one embodiment, an apparatus for performing a safety function includes an electronic circuit including a switching element, a first resistor, and a second resistor, and a processor that controls operation of the electronic circuit such that a first voltage applied to the electronic circuit is converted to a second voltage when a predetermined condition is met.

Description

[Technical Field]

[0001] The present invention relates to a device for performing a safety function and a photovoltaic power generation system including the same. [Background technology]

[0002] Solar power generation systems must ensure stability by detecting abnormal conditions and emergencies that may occur during operation in real time. In the event of an emergency, solar power generation systems must be equipped with safety functions that shut down the output of the photovoltaic (PV) module and control the voltage below a safe level within a specific time frame, in accordance with country-specific and product-specific requirements. In this regard, as global standards for industrial safety become more diverse, solar power generation systems are increasingly being required to have a rapid shutdown (RSD) function.

[0003] Meanwhile, in order to improve the performance of PV modules and increase power production efficiency, module level power conversion devices (or module level power conditioning devices) (hereinafter referred to as "Module Level Power Electronics") are being introduced into solar power generation systems.

[0004] On the other hand, there is a demand for devices that can output a stable safe voltage even in an emergency and perform safety functions that are easy to implement. Summary of the Invention [Problem to be solved by the invention]

[0005] To provide a device for performing a safety function, which can perform the safety function more stably in an emergency, and a solar power generation system including the same.

[0006] To provide a device for performing a safety function, which can easily perform the safety function without a complicated configuration such as an integrated circuit, and a solar power generation system including the same. [Means for solving the problem]

[0007] According to one embodiment, an apparatus for performing a safety function includes an electronic circuit including a switching element, a first resistor, and a second resistor, and a processor that controls operation of the electronic circuit such that a first voltage applied to the electronic circuit is converted to a second voltage when a predetermined condition is met.

[0008] According to another aspect, a solar power generation system includes a plurality of PV (Photovoltaic) modules and an apparatus connected to each of the plurality of PV modules, the apparatus including an electronic circuit including a switching element, a first resistor, and a second resistor, and a processor that controls the electronic circuit so that a first voltage applied to the electronic circuit is converted to a second voltage depending on a state of the solar power generation system. [Effects of the Invention]

[0009] Since a safe voltage is output using a resistor, safety functions can be implemented safely without configuring a complex circuit.

[0010] The level of safe voltage can be easily adjusted or set to suit the forward characteristics of the diode.

[0011] The device that executes the safety function can operate stably without imposing a burden on the entire system, such as power loss.

[0012] It is possible to output a safe voltage using simple semiconductor characteristics without the complicated process of setting a safe voltage through the control of a PWM controller.

[0013] A safe voltage can be output with just a simple circuit configuration, eliminating the instability of voltage control that occurs due to complex control algorithms and defects in semiconductor integrated circuits.

[0014] Since the safety voltage level can be designed to match the forward characteristics of a simple diode, the circuit can be quickly modified according to the safety requirements of the user. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating an example of a solar power generation system according to an embodiment. [Figure 2] FIG. 1 is a block diagram illustrating an example of an apparatus for performing a safety function according to one embodiment. [Figure 3] FIG. 2 illustrates an example of an electronic circuit according to one embodiment. [Figure 4] FIG. 10 is a diagram illustrating another example of an electronic circuit according to an embodiment. [Figure 5] FIG. 1 illustrates an example of operation of a device that performs a safety function according to one embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

[0016] According to one embodiment, an apparatus for performing a safety function includes an electronic circuit including a switching element, a first resistor, and a second resistor, and a processor that controls operation of the electronic circuit such that a first voltage applied to the electronic circuit is converted to a second voltage when a predetermined condition is met. DETAILED DESCRIPTION OF THE INVENTION

[0017] The terms used in the embodiments are generally used and widely as much as possible, but these may change depending on the intentions of those skilled in the art, legal precedents, the emergence of new technologies, etc. In addition, in certain cases, the applicant may arbitrarily select terms, and in such cases, the meanings thereof will be described in detail in the relevant description. Therefore, the terms used in the specification should be defined based on the meanings of the terms and the overall content of the specification, rather than simply the names of the terms.

[0018] Throughout the specification, when a part is referred to as "comprising" a certain element, this means that it may further include other elements, rather than excluding other elements, unless specifically stated to the contrary.

[0019] Furthermore, terms including ordinal numbers such as "first" or "second" used in the specification may be used to describe various components, but the components should not be limited by the terms. The terms may be used to distinguish one component from another.

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present invention and is not intended to show the only embodiments in which the present invention can be implemented. In the drawings, parts that are not relevant to the description may be omitted in order to clearly explain the present invention, and the same reference numerals may be used for the same or similar components throughout the specification.

[0021] FIG. 1 is a diagram illustrating an example of a solar power generation system according to an embodiment.

[0022] 1, a solar power generation system 1 includes a PV module 110 and an apparatus 120. Meanwhile, in addition to the components shown in FIG.

[0023] The PV module 110 is a module that generates electricity using sunlight. For example, the system 1 may include a plurality of PV modules 110.

[0024] The device 120 is a device that converts the output voltage of the connected PV module 110 into a predetermined safety voltage when an emergency occurs. An example of the device 120 will be described with reference to Figs. 2 to 4.

[0025] For example, device 120 may be an MLPE, a device connected to an MLPE, or a device included in an MLPE, where the MLPE may be an optimizer or a micro inverter.

[0026] As an example, if the MLPE is an optimizer, the system 1 may include a single inverter. In this case, the single MLPE may be connected to a single PV module 110, and the MLPE may optimize the power output from the PV module 110 and output it to a single inverter (e.g., a string inverter). The current converted by the inverter (e.g., converting direct current to alternating current) may be output to a load or the grid.

[0027] 1, a single device 120 can be connected to a single PV module 110, but is not limited to this. For example, depending on the structure adopted by the photovoltaic power generation system 1, the PV modules 110 and devices can be connected in a many-to-one or many-to-many configuration, and the connection topology is not limited to either. In another embodiment, the system 1 can be configured in a configuration in which multiple groups, each consisting of n PV modules 110 (n is a natural number of 2 or more) and n devices 120, are connected in series.

[0028] Furthermore, although not shown in FIG. 1, the solar power generation system 1 may include an MLPE, an inverter, or a grid.

[0029] The device 120 can share resources such as a processor embedded in the MLPE. Therefore, the MLPE can be connected to the PV modules 110 in a one-to-one correspondence, but is not limited to this. For example, depending on the structure adopted by the photovoltaic power generation system 1, the PV modules 110 and the MLPEs can be connected in a many-to-one or many-to-many correspondence, and the connection form is not limited to either one.

[0030] For example, if the MLPE is an optimizer, the inverter may be installed in a power conversion system (PCS) to convert the power produced by the PV module 110 to a load or to supply the power to the grid.

[0031] The device 120, the MLPE, or the inverter analyzes various data received from the PV module 110, the MLPE, the load, the grid, etc. to monitor the operating status of the system 1. If an abnormality occurs during monitoring, i.e., if it is necessary to switch to a safe mode, a safe voltage can be output via the device 120.

[0032] When the system 1 includes an MLPE, the output voltage of the PV module 110 can be converted to a safe voltage by controlling the switching elements of the buck converter. In this case, a PWM (Pulse Width Modulation) controller must be provided to control the switching elements. Therefore, if the PWM controller fails or an error occurs in the control algorithm, the safe voltage may not be accurately output or controlled. In addition, since the PWM controller and switching elements are generally implemented using semiconductor integrated circuits (ICs), their control and circuit implementation are not simple.

[0033] On the other hand, if the system 1 does not include an MLPE, the output voltage of the PV module 110 can be converted to a safe voltage by controlling a separate regulator such as an LDO (Low Dropout). However, even in the case of a regulator, it is implemented using a semiconductor integrated circuit (IC), so the control of the regulator and circuit implementation are not simple.

[0034] The present invention proposes a device 120 that can stably execute safety functions in accordance with standards and can easily execute safety functions without being configured in a complex manner using integrated circuits or the like.

[0035] The configuration and operation of the device 120 according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0036] FIG. 2 is a block diagram illustrating an example of a device that performs a safety function according to one embodiment.

[0037] Referring to FIG. 2, the device 120 includes an electronic circuit 121 and a processor 122 .

[0038] The electronic circuit 121 can convert the output voltage of the PV module 110 into a safe voltage. An example of the electronic circuit 121 will be described with reference to FIGS.

[0039] The processor 122 controls the electronic circuit 121 according to the state of the photovoltaic power generation system 1. For example, the processor 122 can control the electronic circuit 121 when a predetermined condition is satisfied. Here, when the predetermined condition is satisfied, it means that it is inappropriate for the PV module 110 to output the output voltage as is. For example, when the predetermined condition is satisfied, it may be necessary to switch to a safe mode.

[0040] For example, processor 122 may be, but is not limited to, a processor separately provided for executing a safety function. For example, processor 122 may be a processor included in MLPE. If processor 122 is a processor included in MLPE, the configuration of device 120 may be simpler and production costs may be reduced. For convenience of explanation, processor 122 will be described below as a processor included in MLPE.

[0041] For example, the processor 122 may include a microcontroller unit (MCU) for power control. The processor 122 may execute software such as a program to control components (e.g., hardware or software components) included in the device 120 or the MLPE, and may process various data or perform calculations.

[0042] For example, the processor 122 may be in serial communication with the inverter or may perform Power Line Communication (PLC) to receive control signals, shutdown signals, etc. required for power optimization.

[0043] For example, the processor 122 can receive a shutdown signal from an inverter that monitors the overall operating status of the solar power generation system 1, but is not limited to this.

[0044] For example, the processor 122 can monitor the operating status of the MLPE and generate a shutdown signal by detecting an abnormality. Specifically, the processor 122 analyzes the operating data of the MLPE and various data received from the PV module 110, the load, the grid, etc. to monitor the operating status, and can generate a shutdown signal when an abnormality occurs.

[0045] FIG. 3 is a diagram illustrating an example of an electronic circuit according to an embodiment.

[0046] Referring to FIG. 3, when switching to the safe mode, the electronic circuit 1211 reduces the output voltage V pv to a safe voltage V safety voltage Convert it to and output it.

[0047] The electronic circuit 1211 may include a switching element SW, a first resistor R1, and a second resistor R2. For example, the switching element SW and the first resistor R1 may be connected in parallel, and the second resistor R2 may be connected in series with the parallel connection of the switching element SW and the first resistor R1.

[0048] In this case, the position between the parallel connection of the switching element SW and the first resistor R1 and the second resistor R2 is not limited to any particular position. For example, in addition to the electronic circuit 1211 shown in FIG. 3, the parallel connection of the switching element SW and the first resistor R1 can be disposed on a line connected to the anode (+) output terminal of the PV module 110.

[0049] For example, the switching element SW can be implemented using, but is not limited to, a field effect transistor (FET), a bipolar junction transistor (BJT), etc. In other words, anything that can be turned on or off under the control of the processor 122 can be used as the switching element SW without any restrictions.

[0050] The processor 122 can control the electronic circuit 1211 according to the state of the solar power generation system 1. For example, when a predetermined condition is satisfied, the processor 122 can control the electronic circuit 121. For example, when it is necessary to switch to the safe mode, the processor 122 can input an off signal to the switching element SW (i.e., turn it off).

[0051] When the switching element SW is turned off, the output voltage V of the PV module 110 applied to the electronic circuit 1211 pv is distributed in proportion to the resistance values ​​of the first resistor R1 and the second resistor R2. Therefore, the electronic circuit 1211 can output a safe voltage across the second resistor R2 by turning off the switching element SW.

[0052] In other words, the voltage across the second resistor R2 is the safe voltage V safety voltage Since the voltage is output at a constant voltage, the resistance values ​​of the first resistor R1 and the second resistor R2 can be determined taking into consideration the standard for safe voltage output of the system 1 and the structure of the system 1. Here, the resistance value of the first resistor R1 may be equal to or greater than the resistance value of the second resistor R2. For example, the resistance value of the first resistor R1 may be much greater than the resistance value of the second resistor R2.

[0053] As described above, the processor 122 outputs a safe voltage using a resistor through the simple principle of voltage division law, so that the safety function can be safely performed even if the electronic circuit 1211 is not configured as a complex circuit.

[0054] Furthermore, the electronic circuit 1211 can eliminate the instability of safe voltage control caused by existing complex control algorithms and defects in semiconductor integrated circuits (ICs).

[0055] Furthermore, even if the range of the output voltage of the PV module 110 is high, the resistor division by the processor 122 alone is sufficient to control a safe voltage.

[0056] FIG. 4 is a diagram illustrating another example of an electronic circuit according to an embodiment.

[0057] 3 and 4, the electronic circuit 1212 in Fig. 4 differs from the electronic circuit 1211 in Fig. 3 in that it further includes a diode D. Therefore, the first resistor R1, the second resistor R2, and the switching element SW of the electronic circuit 1212 are the same as those of the electronic circuit 1211 in Fig. 3, and therefore a detailed description thereof will be omitted.

[0058] The diode D is connected in series with the second resistor R2 and the parallel connection of the switching element SW and the first resistor R1.

[0059] 3, the positions of the parallel connection of the switching element SW and the first resistor R1 and the series connection of the second resistor R2 and the diode D are not limited to either. For example, in addition to the electronic circuit 1212 shown in FIG. 4, the parallel connection of the switching element SW and the first resistor R1 can be placed on a line connected to the anode (+) output terminal of the PV module 110. Note that the positions of the second resistor R2 and the diode D are not limited to those shown in FIG. 4, and their placement can be alternated.

[0060] As described above with reference to FIG. 3, when it is necessary to switch to the safe mode, the processor 122 can input an OFF signal to (ie, turn OFF) the switching element SW.

[0061] When the switching element SW is turned off, the output voltage V of the PV module 110 applied to the electronic circuit 1212 pvis distributed in proportion to the resistance values ​​of the first resistor R1, the second resistor R2 and the diode D.

[0062] At this time, the safe voltage V safety voltage is the sum of the forward voltage of the diode D and the voltage distributed to the second resistor R2. That is, the electronic circuit 1212 can output a safe voltage across the second resistor R2 and the diode D by turning off the switching element SW.

[0063] Therefore, the resistance values ​​of the first resistor R1 and the second resistor R2 can be determined taking into consideration the resistance value of the diode D, the standard for the safe voltage output of the system 1, and the structure of the system 1. In addition, the resistance value of the first resistor R1 may be equal to or greater than the resistance value of the second resistor R2. For example, the resistance value of the first resistor R1 may be much greater than the resistance value of the second resistor R2.

[0064] On the other hand, the output voltage V of the PV module 110 varies depending on the characteristics of the product, such as the manufacturer and materials. pv (In particular, the maximum output voltage V oc ) may differ depending on the type of PV module 110. pv The range may vary.

[0065] If the device 120 includes a diode D, the forward voltage of the diode D is constant, so the execution device 120 can generate the required safe voltage V regardless of the manufacturer or product characteristics of the PV module 110. safety voltage can be output stably.

[0066] As described above, the electronic circuit 1212 is a circuit implemented using the simple semiconductor characteristics of a diode, so that a safe voltage level can be easily adjusted and set to match the forward characteristics of the diode D.

[0067] Furthermore, since the voltage value across the diode D is constant, a safe voltage can be easily output regardless of the type of PV module 110.

[0068] In addition, a safe voltage can be output using simple semiconductor characteristics without the complicated process of setting a safe voltage through the control of a PWM controller.

[0069] Furthermore, since the required safety voltage level can be designed to match the simple forward diode characteristics, the circuit can be quickly modified according to the safety requirements of the user.

[0070] FIG. 5 is a diagram illustrating an example of operation of a device that performs a safety function according to one embodiment.

[0071] In step S10, the processor 122 determines whether or not switching to the safe mode is necessary, in other words, the processor 122 determines whether or not a predetermined condition is met.

[0072] For example, the processor 122 can monitor the state of the system 1 and determine whether or not a switch to a safe mode is necessary depending on whether an abnormality has occurred. Here, the safe mode can include an RSD mode.

[0073] Alternatively, the processor 122 may identify that a switch to safe mode is necessary if it receives a shutdown signal from the inverter.

[0074] Furthermore, device 120 can be used to check for a failure of an MLPE. In this case, system 1 can be switched to safe mode by an operator such as an installer, and a failure of an MLPE can be checked via the safe voltage output from device 120.

[0075] If the processor 122 determines that the system 1 needs to switch to the safe mode (Yes in S10), the processor 122 inputs an OFF signal to the switching element SW.

[0076] When the switching element SW is turned off, the electronic circuit 1211 outputs a safe voltage across the second resistor R2, or the electronic circuit 1212 outputs a safe voltage across the second resistor R2 and the diode D.

[0077] If the processor 122 determines that the system 1 does not need to switch to the safe mode (No in S10), the algorithm ends. In other words, if the system 1 operates normally, the switching elements SW of the electronic circuits 1211 and 1212 can be turned on.

[0078] When the switching element SW is turned on, the switching element SW has an ON resistance (RDS(ON)) which is a resistance value between the drain and the source.

[0079] Since the first resistor R1 and the switching element SW are connected in parallel, the combined resistance has a value smaller than the ON resistance RDS(ON), and the output voltage of the PV module 110 is applied directly across the second resistor R2. In other words, when the switching element SW operates in the ON state, the safety function execution device 120 does not affect the system 1.

[0080] As described above, the device 120 can be operated stably without imposing a burden on the system 1 such as power loss.

[0081] Meanwhile, the above-described method can be created as a computer-executable program and can be implemented on a general-purpose digital computer that runs the program using a computer-readable recording medium. Furthermore, the data structure used in the above-described method can be recorded on a computer-readable recording medium by various means. The computer-readable recording medium includes recording media such as magnetic recording media (e.g., ROM, RAM, USB, floppy disk, hard disk, etc.) and optical recording media (e.g., CD-ROM, DVD, etc.).

[0082] It will be understood by those skilled in the art that the present invention can be implemented in modified forms without departing from the essential characteristics of the above description. Therefore, the disclosed method should be considered from an illustrative rather than a restrictive perspective, and the scope of protection is indicated in the claims rather than the above description, and should be interpreted to include all differences within the scope of equivalents thereof.

Claims

1. an electronic circuit including a switching element, a first resistor, and a second resistor; and a processor that controls operation of the electronic circuit such that a first voltage applied to the electronic circuit is converted to a second voltage when a predetermined condition is met.

2. The processor:

2. The apparatus of claim 1, wherein the first voltage is converted to the second voltage by turning off the switching element.

3. The apparatus of claim 1 , wherein the first voltage comprises an output voltage of at least one photovoltaic (PV) module included in a solar power generation system.

4. the switching element and the first resistor are connected in parallel, 2. The apparatus of claim 1, wherein the second resistor is connected in series with the parallel combination of the switching element and the first resistor.

5. the electronic circuit further includes a diode connected in series with the second resistor; The processor: converting the first voltage to the second voltage by turning off the switching element; The apparatus of claim 1 , wherein the second voltage comprises a voltage across the second resistor and the diode.

6. The processor: The apparatus of claim 1 , further comprising: a monitor for monitoring a state of the solar power generation system to identify whether the predetermined condition is met.

7. The apparatus of claim 1 , wherein the predetermined condition comprises a condition that requires the solar power generation system to switch to a safe mode.

8. 2. The apparatus of claim 1, wherein the first resistor has a resistance greater than or equal to the resistance of the second resistor.

9. a plurality of PV (Photovoltaic) modules; a device connected to each of the plurality of PV modules; The device comprises: an electronic circuit including a switching element, a first resistor, and a second resistor; a processor that controls the electronic circuit so that a first voltage applied to the electronic circuit is converted into a second voltage depending on a state of the solar power generation system.

10. The processor:

10. The system of claim 9, wherein the first voltage is converted to the second voltage by turning off the switching element.

11. The system of claim 9 , wherein the first voltage comprises an output voltage of at least one photovoltaic (PV) module included in a solar power generation system.

12. the switching element and the first resistor are connected in parallel, 10. The system of claim 9, wherein the second resistor is connected in series with the parallel combination of the switching element and the first resistor.

13. the electronic circuit further includes a diode connected in series with the second resistor; The processor: converting the first voltage to the second voltage by turning off the switching element; The system of claim 9 , wherein the second voltage comprises a voltage across the second resistor and the diode.

14. The processor: The system of claim 9 , further comprising: monitoring a condition of the solar power generation system to identify whether the predetermined condition is met.

15. 10. The system of claim 9, wherein the first resistor has a resistance greater than or equal to the resistance of the second resistor.

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