Power conversion device and operation method of power conversion device

Abstract

A power conversion device (module level power electronics (MLPE)) according to an aspect may comprise: a converter for receiving an output voltage of a photovoltaic module and outputting a voltage to an inverter; and a processor, wherein the processor configures a range of a maximum power point voltage of the photovoltaic module, determines a control mode on the basis of the output voltage of the photovoltaic module and the range of the maximum power point voltage, and controls the converter to operate in the control mode.

Description

Power conversion device and method of operation of power conversion device

[0001] The present invention relates to a power conversion device and an operating method of the power conversion device.

[0002] A solar power generation system may include module level power electronics (MLPE) to increase power generation under certain conditions (e.g., when the solar modules are shaded).

[0003] A module-level power conversion unit is connected to each solar module and performs Maximum Power Point Tracking (MPPT) control to optimize the output voltage of the solar module.

[0004] Conventional maximum power point tracking (MPP) algorithms calculate the maximum power point (MPP) by identifying power fluctuations from voltage fluctuations at the solar module side. However, conventional MPP tracking algorithms can result in unnecessary voltage fluctuations or reduced efficiency due to switching losses caused by unnecessary switching operations. Furthermore, if MPP tracking is performed simultaneously on the inverter and the module-level power conversion device, the control for MPP tracking is performed twice, which is inefficient.

[0005] If the reference voltage for switching the converter's control mode is inaccurate, the module-level power converter connected to the unshaded solar module will continue to operate the converter. This results in reduced efficiency due to switching losses.

[0006] The technical problem of the present invention is to provide a power conversion device and an operating method of the power conversion device.

[0007] A power conversion device according to one aspect includes a converter that receives an output voltage of a photovoltaic module and converts the voltage; and a processor; wherein the processor sets a range of a maximum power point voltage of the photovoltaic module, determines a control mode based on the range of the output voltage of the photovoltaic module and the maximum power point voltage, and controls the converter to operate in the control mode.

[0008] A photovoltaic module according to another aspect may include the power conversion device described above.

[0009] A method performed by a power conversion device according to another aspect comprises the steps of: setting a range of a maximum power point voltage of a solar module connected to a converter; determining a control mode based on an output voltage of the solar module and the range of the maximum power point voltage; and controlling the converter to operate in the control mode.

[0010] According to another aspect, a computer-readable recording medium includes a recording medium having recorded thereon a program for executing the above-described method on a computer.

[0011] FIG. 1 is a drawing illustrating an example of a power supply structure of a building in which solar modules are installed according to one embodiment.

[0012] FIG. 2 is a schematic diagram illustrating an example of a solar module including a power conversion device according to one embodiment.

[0013] FIG. 3 is a schematic diagram illustrating an example of a power conversion device according to one embodiment.

[0014] FIG. 4 is a diagram illustrating an example of a detailed circuit of a solar module including a power conversion device according to one embodiment.

[0015] FIG. 5 is a diagram illustrating an example of a solar power generation system according to one embodiment.

[0016] FIG. 6 is a diagram illustrating an example of a power conversion device having a three-string structure according to one embodiment.

[0017] FIG. 7 is a diagram illustrating an example of input / output signals and information for switching a control mode of a power conversion device according to one embodiment.

[0018] FIG. 8 is a diagram illustrating an example of an operation flow of a power conversion device according to one embodiment.

[0019] FIG. 9 is a diagram illustrating an example of a control mode switching of a power conversion device according to one embodiment.

[0020] Fig. 10 is a diagram showing an example of a detailed circuit of a converter according to the first embodiment.

[0021] Fig. 11 is a diagram showing an example of a detailed circuit of a converter according to the second embodiment.

[0022] Fig. 12 is a diagram showing an example of a detailed circuit of a converter according to the third embodiment.

[0023] FIG. 13 is a diagram illustrating an example of an operation flow for performing maximum power point voltage tracking according to one embodiment.

[0024] FIG. 14 is a graph illustrating an example of the relationship between power and temperature according to a power reduction mode according to one embodiment.

[0025] A power conversion device according to one aspect includes a converter that receives an output voltage of a photovoltaic module and converts the voltage; and a processor; wherein the processor sets a range of a maximum power point voltage of the photovoltaic module, determines a control mode based on the range of the output voltage of the photovoltaic module and the maximum power point voltage, and controls the converter to operate in the control mode.

[0026] The terms used in the examples are selected from widely used, current terms, as much as possible. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, the applicant may arbitrarily select terms, in which case their meanings will be described in detail in the relevant description. Therefore, the terms used in the specification should be defined based on their intended meaning and the overall content of the specification, rather than simply their names.

[0027] When a part of a specification is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0028] Additionally, terms such as “unit” and “module” described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

[0029] Additionally, 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.

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. In the drawings, portions irrelevant to the description may be omitted for clarity in describing the present invention, and the same reference numerals may be used throughout the specification for identical or similar components.

[0031] FIG. 1 is a drawing illustrating an example of a power supply structure of a building in which solar modules are installed according to one embodiment.

[0032] Referring to Fig. 1, a plurality of photovoltaic modules (2) are installed on the roof of a building (1) and can produce energy using solar energy.

[0033] When a plurality of solar modules (2) are connected, a solar module array can be formed. A solar module array is an assembly of a plurality of solar modules and can include one output terminal.

[0034] Meanwhile, the solar module (2) may include a power conversion device. For example, the power conversion device may include an optimizer to control power conversion of the solar module (2) and optimize energy generation. The power conversion device may monitor the status of the solar module (2), determine whether there is a failure, and transmit data to the outside. In addition, the power conversion device may stop operation by executing a rapid shutdown (RSD) function depending on the situation. In addition, at least one of the solar module (2) and the power conversion device may include a communication module for power line communication.

[0035] The solar module (2) may include a monitoring system or a rapid shutdown system (RSD system).

[0036] The inverter (6) can convert the power generated from the solar module (2) and supply the generated power into the building (1).

[0037] Meanwhile, commercial power transmitted through the power line (3) can be supplied to the building through the transformer (4).

[0038] A plurality of home appliances (7) can be operated by selectively receiving at least one of commercial electricity or power generated by a solar module (2). The power meter (5) can measure the amount of power consumed in the building (1).

[0039] Additionally, if a separate energy storage system (ESS) is installed in the building (1), the power generated from the solar module (2) can be stored in the energy storage system (ESS).

[0040] FIG. 2 is a schematic diagram illustrating an example of a solar module including a power conversion device according to one embodiment.

[0041] FIG. 2 illustrates a solar module (100) and a power conversion device (110). Although FIG. 2 illustrates that the power conversion device (110) is included within the solar module (100), the present invention is not limited thereto. In other words, the power conversion device (110) may be an independent device from the solar module (100).

[0042] A solar module (100) is a module that generates electricity using solar energy. For example, a plurality of solar modules (100) may be connected to form a solar module array.

[0043] The power conversion device (110) can be connected to the solar module (100) to optimize the output voltage of the solar module (100). For example, the power conversion device (110) can optimize the output voltage so that the output of the solar module (100) is maximized. For example, the power conversion device (110) can include a micro-inverter or a DC optimizer. As an example, when the power conversion device (110) is a DC optimizer, a single DC optimizer can be connected to a single solar module (100). In addition, the DC optimizer can be connected to an inverter (e.g., a string inverter). In this case, the DC optimizer can optimize the power output from the solar module (100) and output it to the inverter. The current converted by the inverter (e.g., converted from direct current to alternating current) can be output to a load or a power grid.

[0044] As another example, if the power conversion device (110) is a micro-inverter, a single micro-inverter may be connected to a single solar module (100). In this case, the micro-inverter may convert power generated by the solar module (100), and the converted current may be output to a load or a power grid.

[0045] The power conversion device (110) may be a module-level power electronics (MLPE) connected to a solar module (100), but is not limited thereto. For example, the power conversion device (110) may be a module-level power conversion device and may be included in an inverter. An example of the power conversion device (110) is described with reference to FIG. 3.

[0046] The power conversion device (110) can optimize and output the output voltage of each connected solar module (100) through maximum power point tracking control. The power conversion device (110) can identify the maximum power point voltage by performing maximum power point tracking control that tracks the corresponding power and voltage when the solar module (100) generates maximum power.

[0047] For example, a maximum power point tracking algorithm may be an algorithm that continuously adjusts the impedance of a solar module (100) or an impedance of a solar module array so that the solar power generation system operates near the maximum power point when conditions such as irradiance, temperature, and load change.

[0048] For example, the power conversion device (110) may be connected to the solar modules (100) in a one-to-one correspondence, but is not limited thereto. As another example, the power conversion device (110) may be installed in the solar modules (100) in a many-to-one or many-to-many correspondence, depending on the structure adopted by the solar power generation system. The installation form of the power conversion device (110) and the solar modules (100) is not limited to either one. In addition, when a plurality of power conversion devices (110) are provided, the power conversion devices (110) may be connected in series with each other. If the power conversion device (110) is a DC optimizer, the power conversion devices (110) at both ends of the plurality of power conversion devices (110) connected in series may be connected to an inverter (e.g., a string inverter).

[0049] An inverter may be a component installed in a power conversion system (PCS) that performs power conversion to supply power generated from a solar module (100) to a load or a grid. For example, the inverter may monitor various data received from a solar module (100), a power conversion device (110), a load, a power grid, etc.

[0050] Meanwhile, the power conversion device (110) performs maximum power point tracking control to find the maximum power point voltage by varying the voltage or performing switching control, etc. During this process, power loss may occur. In addition, when the inverter also performs maximum power point tracking control along with the power conversion device (110), there is a problem in that double switching operations occur in the solar power generation system.

[0051] The characteristics of solar cells, such as their output voltage and current, vary depending on the amount of solar radiation and the temperature of the cell. Accordingly, suppliers of solar modules (100) experimentally measure the characteristics of solar modules (100) including solar cells and provide them to consumers as characteristic information.

[0052] The power conversion device (110) can switch the control mode of the power conversion device (110) in various ways based on the maximum power point voltage calculated using characteristic information.

[0053] Hereinafter, the operation of a power conversion device (110) included in a solar module (100) according to one embodiment of the present invention will be specifically described with reference to the drawings.

[0054] FIG. 3 is a schematic diagram illustrating an example of a power conversion device according to one embodiment.

[0055] Referring to FIG. 3, a power conversion device (110) may include a converter (111), a processor (112), and a measuring instrument (113).

[0056] The converter (111) is a device that converts the voltage applied from the solar module (100) (output voltage of the solar module (100)). For example, the converter (111) may include a DC optimizer, a DC / AC inverter, or a micro inverter.

[0057] For example, if the converter (111) is a DC optimizer, it can be implemented as a buck converter that forces the input voltage. However, implementation examples of the converter (111) are not limited to those described above. Examples of the converter (111) are described below with reference to FIGS. 10 to 12.

[0058] For example, the processor (112) may include a microcontroller unit (MCU) for power control. The processor (112) may execute software such as a program to control at least one other component (e.g., hardware or software component) of the power conversion device (110) and perform various data processing or calculations.

[0059] The processor (112) can receive characteristic information of the solar module (100) by performing serial communication with the inverter or power line communication (PLC), or receive control signals, shutdown signals, etc. required for power optimization.

[0060] The processor (112) can control the duty ratio of the converter (111) to convert (regulate) the output voltage of the power conversion device (110). The processor (112) can control the operation of the internal switch(es) included in the converter (111) according to the control mode.

[0061] The measuring device (113) may include a temperature sensor. For example, the temperature sensor may be used to measure the temperature (Tmlpe) of the power conversion device (110) and estimate the temperature (Tpv) of the solar module (100).

[0062] In addition, the measuring device (113) may further include a current sensor for measuring the output current (Ipv) of the solar module (100) at the output terminal of the solar module (100), and a voltage sensor for measuring the output voltage (Vpv) of the solar module (100).

[0063] However, the configuration and operation of the power conversion device (110) are not limited to those described above. For example, the processor (112) can receive the output current (Ipv) and output voltage (Vpv) of the solar module (100) measured from an external device.

[0064] FIG. 4 is a diagram illustrating an example of a detailed circuit of a solar module including a power conversion device according to one embodiment.

[0065] Figure 4 shows detailed configurations of a solar module (100) and a power conversion device (110).

[0066] The processor (112) can receive the output current (Ipv) of the solar module (100), the output voltage (Vpv) of the solar module (100), and the temperature (Tmlpe) of the solar module (100) from the measuring device (113). In addition, the processor (112) can control the converter (111) so that the output voltage (Vpv) of the solar module (100) is driven to the maximum power point voltage (Vmp).

[0067] FIG. 5 is a diagram illustrating an example of a solar power generation system according to one embodiment.

[0068] Referring to FIG. 5, a solar power generation system (500) may include a solar module (100), a power conversion device (110), a power conversion system (PCS) (200), and a power system (300).

[0069] For example, the solar module (100) can form a solar module array, and a plurality of arrays can be connected.

[0070] The power conversion device (110) is connected to each solar module (100) to optimize the output power of each connected solar module (100). For example, the optimized currents (Idc1, Idc2, ..., IdcN) can be transmitted to the primary board of the power conversion system (200).

[0071] The power conversion system (200) may include an energy management system (EMS), an internal processor of the power conversion system (PCS MCU), a DC optimizer, an inverter, etc.

[0072] The inverter can perform power conversion to supply power generated from a solar module (100) to a load or a power system (300).

[0073] FIG. 6 is a diagram illustrating an example of a power conversion device having a three-string structure according to one embodiment.

[0074] Referring to FIG. 6, solar modules (100) and power conversion devices (110) can be configured by bundling three of each other, which is called a three-string structure.

[0075] The processor (112) can control the converter (111) through a gate driver. The processor (112) can change the control mode of the power conversion device (110) using a mode change controller. An example of the processor (112) controlling the converter (111) is described below with reference to FIG. 7.

[0076] The processor (112) can control switch 1 in rapid shutdown mode to limit the output of the solar module (100) to meet the rapid shutdown standard. For example, the U.S. household standard requires that the output of the solar module be reduced to 30 V or less within 30 seconds in the event of an accident such as a fire. The processor (112) can first reduce the output voltage of the converter (111) to 1 V, and if the converter (111) cannot reduce the voltage due to a failure or the like, control switch 1 to turn off. The processor (112) can turn switch 1 off to block the output voltage.

[0077] The processor (112) can control the discharge switch 2 to discharge the residual power through the resistor (R). The processor (112) can discharge the residual power stored in the capacitor of the output terminal of the converter (111) by controlling the switch 2 to turn on. At this time, the switch 1 and the switch 2 can operate complementarily.

[0078] For example, the power conversion device (110) may further include a reactor (L) arranged at the output terminal of the converter (111) and a reactor (L) for PLC communication arranged at the final output terminal of the power conversion device (110).

[0079] FIG. 7 is a diagram illustrating an example of input / output signals and information for switching a control mode of a power conversion device according to one embodiment.

[0080] Referring to FIG. 7, the processor (112) can receive current, voltage, and temperature measurement values ​​through an analog input. The processor (112) can measure the output current (I) of the solar module (100). TOP , I MID , I BOT ), the output voltage of the solar module (VIN TOP , VIN MID , VIN BOT ), the output voltage (VOUT) of the power conversion device (110) TOP , VOUT MID , VOUT BOT ), the temperature of the power conversion device (110) (Temp TOP , Temp MID , Temp BOT ), ambient temperature (Temp AMB ) can be received. At this time, the solar modules and power conversion devices composed of three strings can be distinguished and indicated as Top, Mid, and Bot.

[0081] The processor (112) can switch the control mode using the measurement value received through the analog input unit. For example, the control mode may include an output bypass mode, an input bypass mode, a maximum power point tracking mode, a de-rating mode, a rapid shutdown mode (ESTOP mode), a safety voltage mode, etc. A detailed description of the control mode will be described later with reference to FIG. 9.

[0082] The processor (112) can control the converter (111) using a pulse width modulation signal (PWM signal) to determine a control mode and perform an operation according to the control mode.

[0083] In the case of a 3-string structure, the converter (111) is composed of 3 stages, and the processor (112) sends a pulse width modulation signal (Buck1-Gate) to the gate driver connected to each converter (111) according to the control mode. TOP , Buck1-Gate Bottom , Buck2-Gate TOP , Buck1-Gate Bottom , Buck3-Gate TOP , Buck1-Gate Bottom ) can be transmitted. For example, when the control mode is a rapid shutdown mode, the processor (112) can transmit a pulse width modulation signal (RSD-Gate) to the gate driver connected to switch 1.

[0084] The processor (112) can communicate with the power conversion system (200). The processor (112) can receive, for example, a rapid shutdown mode signal from the power conversion system (200).

[0085] FIG. 8 is a diagram illustrating an example of an operation flow of a power conversion device according to one embodiment.

[0086] The processor (112) can set the range of the maximum power point voltage for determining the control mode (S10). At this time, the range of the maximum power point voltage can have a lower limit (A) and an upper limit (B).

[0087] When a shutdown signal for cutting off power is generated (Yes in S20), the processor (112) can determine the control mode as a rapid shutdown mode or a safe voltage mode (S21).

[0088] If a shutdown signal does not occur (No in S20), the processor (112) can determine a control mode based on the output voltage of the solar module (100) and the identified maximum power point voltage (S30).

[0089] Specifically, when the output voltage of the solar module (100) is lower than the lower limit (A) of the maximum power point voltage, the processor (112) can determine the control mode as an output bypass mode that bypasses the output of the converter (111) (S31).

[0090] When the output voltage of the solar module (100) is higher than the upper limit (B) of the maximum power point voltage, the processor (112) can determine the control mode as an input bypass mode that bypasses the input of the converter (111) (S32).

[0091] When the output voltage of the solar module (100) is a value between the lower limit (A) and the upper limit (B) of the maximum power point voltage, the processor (112) can determine the control mode as the maximum power point tracking (MPPT) mode (S33).

[0092] The control mode of the power conversion device (110) and switching between control modes will be described later with reference to FIG. 9.

[0093] According to the above, the maximum power point voltage can be predicted using only the power of the solar module (100), so maximum power point tracking control is possible without power loss.

[0094] Additionally, the control mode can be stably determined and switched based on the predicted maximum power point voltage.

[0095] In addition, the power conversion device and inverter are efficient because they can perform maximum power point tracking control with the predicted maximum power point voltage without dual operation.

[0096] FIG. 9 is a diagram illustrating an example of a control mode switching of a power conversion device according to one embodiment.

[0097] For example, the control mode of the power conversion device (110) may include an output bypass mode, an input bypass mode, a maximum power point tracking mode, a temp de-rating mode, a rapid shutdown mode (ESTOP mode), a safety voltage mode, etc.

[0098] Referring to FIG. 9, the power conversion device (110) can operate in a safety voltage mode (Stop / Fault) when stopped or an error occurs.

[0099] When the solar module (100) produces electricity, such as during the morning sunrise, and the output voltage of the solar module (100) is above a certain level, the power conversion device (110) can start operating (Start). When operating, the power conversion device (110) can operate in input bypass mode or lamp output bypass mode.

[0100] The power conversion device (110) can switch the control mode according to the level of the output voltage (Vpv) of the solar module (100). For example, when the output voltage (Vpv) of the solar module (100) drops below a certain level below the predicted maximum power point voltage (Vmpp), it can determine that the amount of solar radiation has dropped to a level where power generation is not possible and operate in the ramp output bypass mode. The power conversion device (110) ramps down the duty ratio of the converter (111) in the ramp output bypass mode to enable other power conversion devices to generate power.

[0101] The power conversion device (110) can output voltage to the inverter as the solar module (100) continues to generate power when the operation is started. The inverter can start generating power using the output voltage of the power conversion device (110). The power conversion device (110) can switch from the start state to the normal operation state (Run) when the inverter generates power exceeding a preset power. The power conversion device (110) can switch the control mode using the predicted maximum power point voltage in the normal operation state.

[0102] For example, the range of the maximum power point voltage can be set as a lower limit obtained by multiplying the maximum power point voltage by the output bypass ratio and an upper limit obtained by multiplying the maximum power point voltage by the input bypass ratio. The output bypass ratio and the input bypass ratio can be determined according to the solar module (100) or arbitrarily determined by the operator, and the method for setting or each value is not limited to any one.

[0103] The output bypass mode is a mode that bypasses the output of the converter (111) when the output voltage of the solar module (100) is lower than the lower limit of the maximum power point voltage. At this time, if the range of the maximum power point voltage is the maximum power point voltage value itself, the lower limit of the maximum power point voltage is regarded as the maximum power point voltage value. If the output voltage (Vpv) of the solar module (100) is lowered to a certain level below the predicted maximum power point voltage (Vmpp), it can be determined that the amount of solar radiation has decreased to a level at which power generation is not possible. Accordingly, the converter (111) can operate in the lamp output bypass mode.

[0104] The input bypass mode is a mode that bypasses the input of the converter (111) (the output voltage of the solar module (100)) when the output voltage of the solar module (100) is higher than the upper limit of the maximum power point voltage. At this time, when the range of the maximum power point voltage is the maximum power point voltage value itself, the upper limit of the maximum power point voltage is regarded as the maximum power point voltage value.

[0105] The maximum power point tracking mode is a mode in which the output voltage of the solar module (100) is driven to the maximum power point voltage when the output voltage of the solar module (100) is a value between the lower limit and the upper limit of the maximum power point voltage. At this time, when the range of the maximum power point voltage is the maximum power point voltage value itself, the solar module (100) can be controlled in the maximum power point tracking mode when the output voltage is equal to the maximum power point voltage.

[0106] The power reduction mode is a mode that controls the duty ratio of the converter (111) to limit the output power according to each condition when the temperature of the converter (111) approaches the operating temperature of the internal components or when the temperature of the solar module (100) is lower than the STC condition and the irradiance condition exceeds 1000 W / m2.

[0107] The rapid shutdown mode and safe voltage mode are modes that shut down the solar module (100) or lower the output voltage of the solar module (100) to a predefined safe voltage when an abnormality occurs in the solar module (100) due to monitoring by the processor (112) or inverter.

[0108] The processor (112) can control the converter (111) to operate in one of the above control modes based on the measured output voltage of the solar module (100). A specific control method of the converter (111) for each control mode will be described later with reference to FIGS. 10 to 12, 13, and 14.

[0109] The control modes described above are shown in Table 1 with reference to Figure 9.

[0110] Control Mode Description Reference Drawing Input Bypass Mode (Input Bypass Mode) When the output voltage of the solar module is higher than the upper limit of the maximum power point voltage, the input of the converter (the output voltage of the solar module) is bypassed. 10 Output Bypass Mode (Output Bypass Mode) When the output voltage of the solar module is lower than the lower limit of the maximum power point voltage, the output of the converter is bypassed. 11 Maximum Power Point Tracking Mode (Maximum Power Point Tracking Mode) When the output voltage of the solar module is between the lower limit and the upper limit of the maximum power point voltage, the output voltage of the solar module is driven to the maximum power point voltage. 13 Rapid Shutdown Mode (ESTOP Mode) When a problem occurs in the solar module, the solar module is shut down. 12 Safety Voltage Mode (Safety Voltage Mode) When a problem occurs in the solar module, the output voltage of the solar module is lowered to a predefined safety voltage. Vout = Vsafety voltage. Temp De-rating Mode (Temp De-rating Mode) When the temperature of the converter increases below the internal When the operating temperature of the component is close to the operating temperature or when the temperature of the solar module (100) is lower than the STC condition and the irradiance condition exceeds 1000 W / m2, the duty ratio of the converter is controlled to limit the output power according to each condition. 14

[0111] Fig. 10 is a diagram showing an example of a detailed circuit of a converter according to the first embodiment.

[0112] The control method of the converter (111) for each control mode may vary depending on the structure of the converter (111). Hereinafter, the control method of the converter (111) illustrated in Fig. 10 in the input bypass mode will be described.

[0113] The converter (111) may include a first switch (1010) and a second switch (1020) that complementarily operate on or off. The processor (112) may control the first switch (1010) to operate on and the second switch (1020) to operate off in an input bypass mode. At this time, the processor (112) may control the converter (111) so that the duty ratio of the first switch (1010) increases over time.

[0114] Fig. 11 is a diagram showing an example of a detailed circuit of a converter according to the second embodiment.

[0115] Hereinafter, a control method of the converter (111) illustrated in Fig. 11 in the output bypass mode will be described. The processor (112) can control the first switch (1010) to be turned off and the second switch (1020) to be turned on in the output bypass mode. At this time, the processor (112) can control the converter (111) so that the duty ratio of the first switch (1010) decreases over time in the lamp output bypass mode.

[0116] Fig. 12 is a diagram showing an example of a detailed circuit of a converter according to the third embodiment.

[0117] Hereinafter, a control method of the converter (111) illustrated in Fig. 11 in rapid shutdown mode will be described. The converter (111) of Fig. 11 may further include a third switch (1030) in addition to the first switch (1010) and the second switch (1020) that operate complementarily.

[0118] The processor (112) can control the third switch (1030) to be turned on in the rapid shutdown mode. The processor (112) can control the duty ratio of the first switch (1010) to drive the output voltage (Vpv) of the solar module (100) to a predefined safe voltage in the safe voltage mode.

[0119] FIG. 13 is a diagram illustrating an example of an operation flow for performing maximum power point voltage tracking according to one embodiment.

[0120] The algorithm illustrated in Fig. 13 is a P&O (Perturb and Observe) maximum power point tracking control algorithm. Specifically, the algorithm of Fig. 13 operates by calculating power values ​​using periodically measured output voltage and current values ​​of a solar module (100) and using the increase / decrease rates of necessary elements. By comparing the previous and current power values, and the previous and current voltage (current) values, the operating point position can be identified, and the maximum power point can be tracked by increasing or decreasing the duty ratio (D).

[0121] The processor (112) can control the output voltage (Vpv) of the solar module to drive it to the maximum power point voltage in the maximum power point tracking mode. For example, the processor (112) can control the duty ratio of the first switch (1010) of the converter (111) illustrated in FIG. 10.

[0122] FIG. 14 is a graph illustrating an example of the relationship between power and temperature according to a power reduction mode according to one embodiment.

[0123] The processor (112) controls the power reduction mode based on two internal measurement temperature values, a peak value and an average value (Avg value), for derating.

[0124] Referring to FIG. 14, the temperature axis (x-axis) represents the temperature of the power reduction mode exit condition (derating exit temp), the temperature of the power reduction mode entry condition (derating enter temp), the reference temperature point 1 (curve temp1) of the slope for reducing the generated power (derating Power Slope) based on the average temperature, the reference temperature point 2 (curve temp2) of the slope for reducing the generated power (derating Power Slope) based on the average temperature, and the reference temperature (Fault temp) at which a temperature error (Fault) occurs.

[0125] The processor (112) can control the converter (111) in a power reduction mode when the temperature of the converter (111) approaches the operating temperature of the internal components or when the temperature of the solar module (100) is lower than the STC condition and the irradiance condition exceeds 1000 W / m2. For example, the processor (112) can control the duty ratio of the first switch (1010) of the converter (111) illustrated in FIG. 10 to be reduced.

[0126] Meanwhile, the above-described method can be written as a program that can be executed on a computer, and can be implemented on a general-purpose digital computer that runs the program using a computer-readable recording medium. In addition, the structure of the data used in the above-described method can be recorded on a computer-readable recording medium through various means. The computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM, RAM, USB, floppy disk, hard disk, etc.) and optical reading media (e.g., CD-ROM, DVD, etc.).

[0127] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described invention. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the claims, not the foregoing description, is defined by the scope of the patent, and should be interpreted to encompass all differences within the scope equivalent thereto.

[0128] The implementations described herein may be implemented as, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Even if discussed only in the context of a single form of implementation (e.g., discussed only as a method), the implementation of the discussed features may also be implemented in other forms (e.g., as an apparatus or a program). An apparatus may be implemented using suitable hardware, software, firmware, and the like. A method may be implemented in an apparatus such as a processor, which generally refers to a processing device including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. A processor also includes a communication device such as a computer, a cell phone, a personal digital assistant ("PDA"), and other devices that facilitate the communication of information between end-users.

Claims

1. In power conversion devices (Power Electronics), A converter that converts the output voltage of a photovoltaic module; and including a processor; The above processor, A power conversion device that sets a range of the maximum power point voltage of the solar module, determines a control mode based on the range of the output voltage of the solar module and the maximum power point voltage, and controls the converter to operate in the control mode.

2. In paragraph 1, The above processor, A power conversion device that determines an output bypass mode that bypasses the output of the converter as the control mode when the output voltage of the solar module is lower than the lower limit of the maximum power point voltage.

3. In paragraph 2, The above converter is, Comprising a first switch and a second switch that operate complementarily on or off, The above processor, A power conversion device that controls the first switch to be turned off and the second switch to be turned on in the above output bypass mode.

4. In paragraph 3, The above processor, A power conversion device that controls the converter so that the duty ratio of the first switch decreases over time.

5. In paragraph 1, The above processor, A power conversion device that determines an input bypass mode that bypasses the input of the converter as the control mode when the output voltage of the solar module is higher than the upper limit of the maximum power point voltage.

6. In paragraph 5, The above converter is, Comprising a first switch and a second switch that operate complementarily on or off, The above processor, A power conversion device that controls the first switch to operate on and the second switch to operate off in the input bypass mode.

7. In paragraph 6, The above processor, A power conversion device that controls the converter so that the duty ratio of the first switch increases over time.

8. In paragraph 1, The above processor, A power conversion device that determines the maximum power point tracking (MPPT) mode as the control mode when the output voltage of the solar module is a value between the upper limit and the lower limit of the maximum power point voltage.

9. In paragraph 8, The above processor, A power conversion device that controls the converter to drive the output voltage of the solar module to the maximum power point voltage in the maximum power point tracking mode.

10. In paragraph 1, The above processor, A power conversion device that determines the control mode as a rapid shutdown mode or a safe voltage mode when a shutdown signal for cutting off power is generated.

11. In paragraph 1, The above power conversion device, A power conversion device comprising a module level power electronics (MLPE).

12. In paragraph 1, The above power conversion device is a power conversion device built into an inverter.

13. In photovoltaic modules, A solar module comprising a power conversion device according to claim 1.

14. In a method performed by a power conversion device, A step for setting the range of maximum power point voltage of a solar module connected to a converter; A step of determining a control mode based on the range of the output voltage of the solar module and the maximum power point voltage; and A method comprising: a step of controlling the converter to operate in the above control mode; 15. In paragraph 14, The above controlling step is, A method for determining an output bypass mode that bypasses the output of the converter as the control mode when the output voltage of the solar module is lower than the lower limit of the maximum power point voltage.

16. In paragraph 15, The above controlling step is, A method for controlling a first switch included in the converter to be turned off and a second switch included in the converter to be turned on in the above output bypass mode.

17. In paragraph 14, The above controlling step is, A method for determining an input bypass mode that bypasses the input of the converter as the control mode when the output voltage of the solar module is higher than the upper limit of the maximum power point voltage.

18. In paragraph 17, The above controlling step is, A method for controlling a first switch included in the converter to operate on in the above input bypass mode and a second switch included in the converter to operate off.

19. In paragraph 14, The above controlling step is, A method for determining a maximum power point tracking (MPPT) mode as the control mode when the output voltage of the solar module is a value between the upper limit and the lower limit of the maximum power point voltage.

20. A computer-readable recording medium recording a program for executing the method of Article 14 on a computer.

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