Power conversion device and method for controlling power conversion device

Abstract

An aspect provides a power conversion device including a short-circuit detection device of a switching element, the short-circuit detection device including: a voltage application module for applying a gate voltage to the switching element; a voltage detection module for detecting the voltage of each terminal of the switching element; and a processor for determining a short circuit of the switching element on the basis of the waveform of the voltage detected through the voltage detection module as the gate voltage for the switching element is applied, increased, and decreased, wherein the power conversion device may be supplied with power from a solar module.

Description

Power conversion device and control method thereof

[0001] The present invention relates to a power conversion device for a solar module and a control method for the power conversion device.

[0002] Solar modules generate electricity using sunlight, and power conversion devices are connected to solar modules to optimize the output voltage of the solar modules.

[0003] The power conversion device can vary the voltage or perform switching control, etc. for maximum power point tracking control. For this purpose, the power conversion device can include a plurality of switching elements.

[0004] Therefore, power conversion devices need to detect short circuits in switching elements in advance.

[0005] A representative method for detecting a short circuit in a switching element of a power conversion device is the DESAT (Desaturation) method.

[0006] The DESAT method detects short circuits by utilizing overcurrent caused by the short circuit current of a switching element while power is applied to the power stage. However, the DESAT method has a problem in that short circuits must be detected during the operation of the switching element. In other words, to detect a short circuit, an overcurrent flows through the switching element, and this overcurrent can damage component elements and peripheral circuits. Therefore, there is a need for a technology that can detect short circuits in advance of operation through power-less switching of the switching element.

[0007] Additionally, the DESAT method requires additional circuitry to detect short circuits in switching elements and switch them off accordingly. Therefore, the overall circuit size and cost can increase.

[0008] Accordingly, there is a growing demand for short-circuit detection devices implemented in smaller size and at lower cost using simpler circuits.

[0009] The technical problem of the present invention is to provide a power conversion device for a solar module and a control method for the power conversion device.

[0010] A power conversion device according to one aspect includes a short circuit detection device of a switching element, the short circuit detection device including: a voltage application module that applies a gate voltage to the switching element; a voltage detection module that detects voltages of each terminal of the switching element; and a processor that determines a short circuit of the switching element based on a waveform of a voltage detected through the voltage detection module according to application, increase, and decrease of the gate voltage to the switching element; and the power conversion device can receive power from a solar module.

[0011] A control method of a power conversion device for detecting a short circuit of a switching element according to another aspect includes: a step in which a processor of a short circuit detection device of a switching element included in the power conversion device applies a gate voltage to the switching element through a voltage application module; a step in which the processor detects voltages of each terminal of the switching element through a voltage detection module; and a step in which the processor determines a short circuit of the switching element based on a waveform of a voltage detected through the voltage detection module according to application, increase, and decrease of the gate voltage to the switching element; wherein the power conversion device can receive power from a solar module.

[0012] 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.

[0013] Figure 1 is an exemplary diagram of a power supply structure of a building in which solar modules are installed according to one embodiment.

[0014] FIG. 2 is an exemplary diagram of a solar module including a power conversion device according to one embodiment.

[0015] FIG. 3 is an exemplary diagram of a short-circuit detection device of a switching element included in a power conversion device for a solar module according to one embodiment.

[0016] FIG. 4 is an exemplary diagram for explaining a switching element that is a target of short-circuit detection, its parasitic capacitor, and gate voltage in a short-circuit detection device of a switching element included in a power conversion device for a solar module according to one embodiment.

[0017] FIG. 5 is an exemplary diagram for explaining the direction of current flowing in the parasitic capacitor of the switching element according to the application of gate voltage in FIG. 4.

[0018] FIG. 6 is an example diagram of the normal voltage waveform of the gate voltage and parasitic capacitor according to the application of the gate voltage in FIG. 5.

[0019] Fig. 7 is a flowchart illustrating an example of a method for detecting a short circuit of a switching element according to one embodiment.

[0020] FIG. 8 is an exemplary diagram of a synchronous buck converter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0021] FIG. 9 is an exemplary diagram of a synchronous buck and boost converter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0022] FIG. 10 is an exemplary diagram of an inverter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0023] A power conversion device including a short circuit detection device of a switching element according to one aspect, the short circuit detection device includes: a voltage application module for applying a gate voltage to the switching element; a voltage detection module for detecting voltages of each terminal of the switching element; and a processor for determining a short circuit of the switching element based on a waveform of a voltage detected through the voltage detection module according to application, increase, and decrease of the gate voltage to the switching element, wherein the power conversion device can receive power from a solar module.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Figure 1 is an exemplary diagram of a power supply structure of a building in which solar modules are installed according to one embodiment.

[0030] Referring to FIG. 1, a plurality of photovoltaic modules (100) are installed on the roof of a building (1) and can produce energy using solar energy.

[0031] When a plurality of solar modules (200) 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.

[0032] Meanwhile, the solar module (100) may include a power conversion device. For example, the power conversion device (110 of FIG. 2) controls the power conversion of the solar module (100) and may include an optimizer to optimize energy generation. The power conversion device (110 of FIG. 2) may monitor the status of the solar module (100), determine whether there is a failure, and transmit data to the outside. For example, the power conversion device (110 of FIG. 2) may be a device including a converter (i.e., a device that converts alternating current into direct current) and an inverter (i.e., a device that converts direct current into alternating current).

[0033] Additionally, the power conversion device (110 in FIG. 2) 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.

[0034] The solar module (100) may include a monitoring system or a rapid shutdown system (RSD system).

[0035] The inverter (6) can convert power generated from a solar module (100) and supply the generated power into the building (1).

[0036] Meanwhile, commercial power transmitted through the power line (3) can be supplied to the building through the transformer (4).

[0037] 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 (100). The power meter (5) can measure the amount of power consumed in the building (1).

[0038] Additionally, if a separate energy storage system (ESS) is installed in the building (1), the power generated from the solar module (100) can be stored in the energy storage system (ESS).

[0039] FIG. 2 is an exemplary diagram of a solar module including a power conversion device according to one embodiment.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] For example, the power conversion device (110) may be a module-level power conversion device (Module Level Power Electronics, MLPE) configured in module units. Here, the module-level power conversion device may include a micro-inverter or a DC optimizer (or power optimizer).

[0044] A micro-inverter is a small solar inverter installed in a solar module (100). Unlike a string inverter that is centrally located and connected to multiple solar modules, a micro-inverter is a device that is independently connected to each solar module (100) to convert power. For example, if the power conversion device (110) is a micro-inverter, a single micro-inverter can be connected to a single solar module (100). In this case, the micro-inverter can convert power generated by the solar module (100), and the converted current can be output to a load or a power grid.

[0045] A DC optimizer (or power optimizer) is a device that converts direct current power into alternating current power, like an inverter. The DC optimizer is independently connected to a solar module (100), and is a device that combines and optimizes the power (direct current) generated by the solar module (100) and then transmits it to a main inverter (e.g., a string inverter) to convert it into alternating current power. For example, if the power conversion device (110) is a DC optimizer, a single DC optimizer can be connected to a single solar module (100). In this case, the DC optimizer can optimize the power output from the solar module (100) and output it to the main inverter. The current converted by the main inverter (e.g., converting direct current into alternating current) can be output to a load or a power grid.

[0046] The power conversion device (110) may be, but is not limited to, a module-level power conversion device (MLPE) connected to a solar module (100). For example, the power conversion device (110) may also be applied to a microinverter or a DC optimizer. In addition, the power conversion device (110) may be included in a converter or inverter.

[0047] 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. For example, the maximum power point tracking algorithm may be an algorithm that continuously adjusts the impedance of the solar module (100) or the 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.

[0049] According to one embodiment of the present invention, the inverter may be a component installed in a power conversion system (PCS) to perform power conversion in order 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 the solar module (100), the power conversion device (110), the load, the 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. In this process, power loss may occur. In addition, if the inverter also performs maximum power point tracking control together with the power conversion device (110), there is a problem in that double switching operations occur in the solar power generation system.

[0051] Solar cells have different characteristics, such as output voltage and current, 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] FIG. 3 is an exemplary diagram of a short-circuit detection device of a switching element included in a power conversion device for a solar module according to one embodiment.

[0053] Referring to FIG. 3, a short circuit detection device of a switching element included in a power conversion device for a solar module may include a voltage application module (111), a voltage detection module (112), a processor (113), and a storage module (114).

[0054] The voltage application module (111) can apply a gate voltage to the switching element. In addition, the voltage application module (111) can vary the gate voltage. For example, the voltage application module (111) can continuously increase the gate voltage by a specified unit or continuously decrease the gate voltage by a specified unit. The voltage application module (111) can apply the gate voltage and increase or decrease the gate voltage under the control of the processor (113).

[0055] The voltage detection module (112) can detect the voltage of each terminal of the switching element. In addition, the voltage detection module (112) can detect the parasitic capacitor voltage of the switching element. In addition, the voltage detection module (112) can detect the gate voltage of the switching element. For example, the voltage detection module (112) can transmit the detected voltage to the processor (113).

[0056] The processor (113) can apply a gate voltage through the voltage application module (111) and control the increase or decrease of the gate voltage. For example, the processor (113) can determine a short circuit of the switching element based on the waveform of the voltage (e.g., gate voltage, parasitic capacitor voltage) detected through the voltage detection module (112) according to the application, increase, and decrease of the gate voltage to the switching element.

[0057] The storage module (114) can store in advance information on the voltage waveform of the normal switching element (i.e., the gate voltage waveform of the normal switching element according to the application, increase, and decrease of the gate voltage, and the parasitic capacitor voltage waveform).

[0058] The processor (113) can determine a short circuit of the switching element by comparing the voltage waveform information (i.e., the gate voltage waveform of the normal switching element according to the application, increase, and decrease of the gate voltage, and the parasitic capacitor voltage waveform) of the normal switching element stored in advance in the storage module (114) with the voltage (e.g., the gate voltage, the parasitic capacitor voltage) waveform detected through the voltage detection module (112).

[0059] For example, the processor (113) can determine that the switching element is short-circuited if the voltage waveform information of the normal switching element stored in advance in the storage module (114) and the change pattern of the voltage waveform detected through the voltage detection module (112) are different (i.e., if the change pattern of the voltage waveform is different by more than the error range).

[0060] Hereinafter, with reference to FIGS. 4 to 6, a method for the processor (113) to detect a short circuit of a switching element will be described.

[0061] FIG. 4 is an exemplary diagram for explaining a switching element that is a target of short-circuit detection, its parasitic capacitor, and gate voltage in a short-circuit detection device of a switching element included in a power conversion device for a solar module according to one embodiment.

[0062] Referring to Fig. 4, a parasitic capacitor (C) is provided between the gate and drain and source of the switching element (Q1). GS : Between Gate-Source, C GD : Between Gate and Drain, C DS : between the drain-source) can be formed. In addition, a gate voltage (V) required for driving the switching element (Q1) is formed between the gate-source of the switching element (Q1). G )(for example, 12V) can be applied.

[0063] FIG. 5 is an exemplary diagram for explaining the direction of current flowing in the parasitic capacitor of the switching element according to the application of gate voltage in FIG. 4.

[0064] Figures 5 (a) and (b) are exemplary diagrams showing the direction of current flowing in a normal switching element and a parasitic capacitor when the gate voltage increases within a specified voltage range (e.g., from 0 V to 12 V). Figures 5 (c) and (d) are exemplary diagrams showing the direction of current flowing in a normal switching element and a parasitic capacitor when the gate voltage decreases within a specified voltage range (e.g., from 12 V to 0 V).

[0065] FIG. 6 is an example diagram of the normal voltage waveform of the gate voltage and parasitic capacitor according to the application of the gate voltage in FIG. 5.

[0066] Referring to Fig. 6, V C_DS is the voltage of the parasitic capacitor between drain and source, V C_GDis the voltage of the parasitic capacitor between the gate and drain, V C_GS is the voltage of the parasitic capacitor between gate and source, V G is the gate voltage, V G_TH refers to the threshold voltage of the switching element (Q1).

[0067] Referring to FIGS. 5 and 6 below, the gate voltage (V G ) describes the change in the pattern of the gate voltage and the voltage waveform of each parasitic capacitor according to the applied section.

[0068] ① Section (V G From 0V to V G_TH The first section (see (a) of Fig. 5) that increases to ) is explained as follows.

[0069] The switching element (Q1) is in the off state, and each parasitic capacitor (e.g., C) is turned on by the gate voltage. GS , C GD , C DS ) are all charged, and the parasitic capacitor (C) between drain and source DS ) is the peak voltage (V Peak ) can only be charged up to.

[0070] At this time, the peak voltage (V Peak ) can be calculated as in mathematical formula 1.

[0071] In mathematical expression 1, Z represents impedance.

[0072]

[0073] ② Section (V) G Go V G_TH The second section (see (b) of Fig. 5) in which the voltage of the switching element increases from the starting point to the maximum voltage (e.g., 12 V) is described as follows.

[0074] When the switching element (Q1) is turned on, the parasitic capacitor between the gate and source and the parasitic capacitor between the gate and drain (C GS Wow C GD) is the gate voltage (V G ) increases in response to the increase in drain-source parasitic capacitor (C DS ) can be discharged through the switched element (Q1) that is turned on.

[0075] ③ Section (V) G V at the maximum voltage of the switching element (e.g. 12 V) G_TH The third section (see (c) of Fig. 5)) that decreases to is explained as follows.

[0076] When the switching element (Q1) is on and the gate voltage decreases, the parasitic capacitor between the gate and source and the parasitic capacitor between the gate and drain (C GS Wow C GD ) is the gate voltage (V G ) can decrease in response to a decrease in the

[0077] ④ Section (V G Go V G_TH The fourth section (see (d) of Fig. 5)) that decreases from 0 V to 0 V is described below.

[0078] The switching element (Q1) is turned off, and the parasitic capacitor (C) between the drain and source DS ) occurs. That is, when the switching element (Q1) is turned off, a parasitic capacitor (C) between the drain and the source is momentarily generated. DS ) voltage can increase and then decrease to 0 V.

[0079] Accordingly, when the switching element (Q1) is normal, a change pattern of the voltage waveform as shown in Fig. 6 is detected. However, when a short circuit occurs between the drain and the source, a change pattern of the voltage waveform of a different form from that shown in Fig. 6 may be detected.

[0080] For example, when the switching element (Q1) is normal, the drain-source parasitic capacitor (C) is momentarily turned off as the switching element (Q1) is turned off. DS ) should have a waveform change pattern in which the voltage increases and then decreases to 0 V, but if the switching element (Q1) is short-circuited, a different waveform change pattern may be detected.

[0081] Also, if the switching element (Q1) is short-circuited, the gate voltage (V G ) begins to be applied, the parasitic capacitor (C) between the drain and source DS ) voltage may not be generated. In addition, in the second section (②), the parasitic capacitor (C) between the drain and source DS ) voltage change may not occur.

[0082] That is, if the switching element (Q1) is short-circuited, the parasitic capacitor (C) between drain and source DS ) can remain 0 V throughout the entire period (i.e., the peak voltage (V Peak ) may not occur).

[0083] Accordingly, the processor (113) can determine that the switching element is short-circuited if the voltage waveform information (e.g., voltage waveform change pattern information) of the normal switching element stored in advance in the storage module (114) and the voltage waveform detected through the voltage detection module (112) are different (i.e., if the voltage waveform change pattern is different by more than the error range).

[0084] Fig. 7 is a flowchart illustrating an example of a method for detecting a short circuit of a switching element according to one embodiment.

[0085] Referring to FIG. 7, the processor (113) applies a gate voltage (V) to the switching element (Q1) to be detected as a short circuit. G ) (e.g., 12 V) is applied (S101). The gate voltage (V G ) is the first interval specified (e.g., from 0 V to VG_TH ) is increased to (S102), the processor (113) checks whether the change pattern of the voltage waveform detected through the voltage detection module (112) is the same as the voltage waveform change pattern of the normal switching element stored in advance in the storage module (114) within the error range (S103).

[0086] For example, the gate voltage (V G ) is the first interval specified (e.g., from 0 V to V G_TH ) is increased to (S102), the processor (113) is turned on when the switching element (Q1) is in the off state and each parasitic capacitor (e.g., C) is turned on by the gate voltage. GS , C GD , C DS ) are all charged, and the parasitic capacitor (C) between drain and source DS ) is the peak voltage (V Peak ) is detected (i.e., the voltage waveform change pattern of a normal switching element).

[0087] If the gate voltage (V G ) is the first section (e.g. from 0 V to V G_TH ) increases (S102), if the detected voltage waveform change pattern is different from the voltage waveform change pattern of the normal switching element by more than the error range (No in S103), the processor (113) determines that the target switching element (Q1) is in a short-circuit state (S111).

[0088] Meanwhile, the gate voltage (V G ) is the first section (e.g. from 0 V to V G_TH ) is increased (S102), if the target switching element (Q1) is not judged to be in a short-circuit state (example of S103), the processor (113) increases the gate voltage (V G ) is assigned to a second interval (e.g., V G_TH(S104) Then, the processor (113) checks whether the change pattern of the voltage waveform detected through the voltage detection module (112) is the same as the voltage waveform change pattern of the normal switching element stored in advance in the storage module (114) within the error range (S105).

[0089] For example, the gate voltage (V G ) is a second interval (e.g., V G_TH When the voltage (S104) increases to 12 V, the processor (113) turns on the switching element (Q1), and the gate-source parasitic capacitor and the gate-drain parasitic capacitor (C GS Wow C GD ) is the gate voltage (V G ) increases in response to the increase in drain-source parasitic capacitor (C DS ) checks whether a voltage waveform change pattern (i.e., a voltage waveform change pattern of a normal switching element) discharged through an ON switching element (Q1) is detected (S105).

[0090] If the gate voltage (V G ) is the second section (e.g., V G_TH When the voltage waveform change pattern detected is increased from 12 V to 12 V (S104), if the voltage waveform change pattern of the normal switching element is different from the voltage waveform change pattern of the normal switching element by more than the error range (No in S105), the processor (113) determines that the target switching element (Q1) is in a short-circuit state (S111).

[0091] Meanwhile, the gate voltage (V G ) is the second section (e.g., V G_TH When the target switching element (Q1) is not judged to be in a short-circuit state (example of S105), the processor (113) increases the gate voltage (V G ) to a specified third interval (e.g., 12 V to V G_TH) is reduced to (S106). Then, the processor (113) checks whether the change pattern of the voltage waveform detected through the voltage detection module (112) is the same as the voltage waveform change pattern of the normal switching element stored in advance in the storage module (114) within the error range (S107).

[0092] For example, the gate voltage (V G ) is a designated third section (e.g. 12 V to V G_TH ) is reduced to (S106), the processor (113) is in an on state, and the gate voltage is reduced, thereby reducing the gate-source parasitic capacitor and the gate-drain parasitic capacitor (C GS Wow C GD ) is the gate voltage (V G ) is detected (S107).

[0093] If the gate voltage (V G ) is the third section (e.g. from 12V to V G_TH ) is reduced to (S106), if the detected voltage waveform change pattern is different from the voltage waveform change pattern of the normal switching element by more than the error range (No in S107), the processor (113) determines that the target switching element (Q1) is in a short-circuit state (S111).

[0094] Meanwhile, the gate voltage (V G ) is the fourth section (e.g., V G_TH When the voltage is reduced to 0 V (S108), if the target switching element (Q1) is not determined to be in a short-circuit state (example of S109), the processor (113) can determine that the target switching element (Q1) is in a normal state (S110).

[0095] For example, the gate voltage (V G ) is the fourth section (e.g., V G_THWhen the voltage (S108) is reduced to 0 V, the processor (113) turns off the switching element (Q1) and the parasitic capacitor (C) between the drain and source DS ) occurs, the parasitic capacitor (C) between the drain and source is momentarily turned off as the switching element (Q1) is turned off. DS ) is detected (S109). It is checked whether a voltage waveform change pattern in which the voltage of the switching element increases and then decreases to 0 V (i.e., a voltage waveform change pattern of a normal switching element) is detected.

[0096] If the gate voltage (V G ) is the fourth section (e.g., V G_TH When the voltage waveform change pattern detected is different from the voltage waveform change pattern of the normal switching element by more than the error range (No in S109), the processor (113) determines that the target switching element (Q1) is in a short-circuit state (S111).

[0097] In addition, if the voltage waveform change patterns detected in the first to fourth sections are the same within the error range, the processor (113) can determine that the target switching element (Q1) is in a normal state (S110).

[0098] FIG. 8 is an exemplary diagram of a synchronous buck converter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0099] Referring to Fig. 8, the power stage terminals (In+, In-) are in a power-free state with no power applied, the high-side switching element (High-side MOSFET, QH) is in an off state, and the switching element (Q) that is the target of short-circuit detection L ) is assumed to be in an unknown state. At this time, the switching element (Q L ) of the parasitic capacitor (C GS , C GD , C DS ) and gate voltage (VG ) is the same as the circuit configuration shown in Fig. 4.

[0100] However, the switching element (Q L ) drain-source parasitic capacitor (C DS ) In order to sense the voltage, Fig. 8 further includes a circuit (voltage detection module (112) of Fig. 3) that detects the voltage by a voltage divider resistor (R1, R2). At this time, the switching element (Q L ) drain-source parasitic capacitor (C DS ) Since the voltage may exceed the voltage that the processor (113) can receive, the processor (113) can detect the voltage across one resistor (e.g., R1 or R2) and calculate the actual voltage based on the ratio of the voltages across the two ends.

[0101] Accordingly, the processor (113) has a gate voltage (V G ) can be increased within a specified voltage range (e.g., from 0 V to 12 V) and then decreased within a specified voltage range (e.g., from 12 V to 0 V), and the change pattern of the voltage waveform can be checked.

[0102] Accordingly, as shown in Fig. 6, within the error range, the parasitic capacitor voltage (V) between the drain and source of a normal switching element C_DS ) When a change pattern of a voltage waveform such as a waveform is detected, the processor (113) switches the switching element (Q L ) can be judged to be normal. If, within the error range, a change pattern of another voltage waveform is detected, the processor (113) switches the switching element (Q L ) can be judged to be a paragraph.

[0103] FIG. 9 is an exemplary diagram of a synchronous buck and boost converter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0104] For example, a synchronous buck and boost converter topology circuit may be a converter topology circuit that can be used as a buck converter (or step-down converter) or a boost converter (or step-up converter) depending on the on / off of switching elements (QH1, QH2, QL1, QL2).

[0105] When complementary switching is performed between the switching element (QH1) at the front end of the inductor (L) and the switching element (QL1) while the switching element (QL2) at the rear end of the inductor (L) is turned OFF and the switching element (QH2) is fixed to ON, the synchronous buck and boost converter topology circuit operates as a buck converter. Conversely, when complementary switching is performed between the switching element (QL1) at the front end of the inductor (L) and the switching element (QH1) is fixed to ON, the synchronous buck and boost converter topology circuit can operate as a boost converter.

[0106] In the synchronous buck and boost converter topology circuit, short-circuit detection of switching elements (QL1, QL2) is performed when no power is applied to the power stage terminals (In+, In-), all high-side switching elements (High-side MOSFETs, QH1, QH2) are in the off state, and the switching elements (Q) that are the targets of short-circuit detection are L1 , Q L2 ) is assumed to proceed in a state where it is unknown whether or not it is a short circuit.

[0107] At this time, each switching element (Q) in each converter circuit in front and behind the inductor (L) L1, Q L2 ) drain-source parasitic capacitor (C DS1 , C DS2) In order to sense the voltage, Fig. 9 may further include a circuit (voltage detection module (112) of Fig. 3) that detects the voltage by the voltage dividing resistors ((R11, R21), (R12, R22)) of each converter circuit. At this time, the switching element (Q L1, Q L2 ) drain-source parasitic capacitor (C DS1 , C DS2 ) voltage may exceed the voltage that the processor (113) can receive, the processor (113) can detect the voltage across one end of the resistor (e.g., (R11 or R21), (R12 or R22)) of each converter circuit and calculate the actual voltage according to the ratio of the voltages across the two ends.

[0108] The processor (113) controls the gate voltage (V) in each converter circuit. G1 , V G2 ) can be increased within a specified voltage range (e.g., from 0 V to 12 V) and then decreased within a specified voltage range (e.g., from 12 V to 0 V) ​​to check the change pattern of the voltage waveform.

[0109] Accordingly, as shown in Fig. 6, within the error range, the parasitic capacitor voltage (V) between the drain and source of a normal switching element C_DS ) When a change pattern of a voltage waveform such as a waveform is detected, the processor (113) switches the switching element (Q) of each converter circuit L1, Q L2 ) can be judged to be normal. If, within the error range, a change pattern of another voltage waveform is detected, the processor (113) switches the switching element (Q) of each converter circuit L1, Q L2 ) can be judged to be a paragraph.

[0110] As described above, the processor (113) detects whether a switching element is short-circuited prior to driving the converter, enabling a response based on the detection of a short-circuit. Accordingly, secondary accidents and damage to peripheral circuits can be prevented in advance.

[0111] FIG. 10 is an exemplary diagram of an inverter topology circuit including a switching element capable of detecting a short circuit according to one embodiment.

[0112] Referring to Fig. 10, the inverter topology circuit may be a power conversion topology circuit that converts direct current into alternating current according to the ON / OFF of the switching elements (Q11, Q13).

[0113] For example, in an inverter topology circuit, switching elements (Q11 and Q14) can operate simultaneously, and switching elements (Q12 and Q13) can operate complementarily.

[0114] For example, when the section in which switching elements (Q11 and Q14) are ON and switching elements (Q12 and Q13) are OFF is referred to as section 1, a (+) voltage can be applied to the load in section 1. On the other hand, when the section in which switching elements (Q12 and Q13) are ON and switching elements (Q11 and Q14) are OFF is referred to as section 2, a (-) voltage can be applied to the load in section 2. At this time, if the width of the pulse applied to the switching elements in sections 1 and 2 is adjusted, a sinusoidal AC can be applied to the load.

[0115] In the inverter topology circuit, it is assumed that the power stage terminals (In+, In-) are in a non-powered state with no power applied, the switching elements (Q11, Q13) that are not targets for short-circuit detection are in an off state, and the short-circuit status of the switching elements (Q12, Q14) that are targets for short-circuit detection is unknown.

[0116] At this time, the parasitic capacitor (C) between the drain and source of each switching element (Q12, Q14) in the inverter topology circuitDS1 , C DS2 ) In order to sense the voltage, Fig. 10 may further include a circuit (voltage detection module (112) of Fig. 3) that detects the voltage by the voltage dividing resistors ((R11, R21), (R12, R22)) of each inverter circuit. At this time, the parasitic capacitor (C) between the drain and source of the switching elements (Q12, Q14) DS1 , C DS2 ) Since the voltage may exceed the voltage that the processor (113) can receive, the processor (113) can detect the voltage across one end of the resistor (e.g., (R11 or R21), (R12 or R22)) of each inverter circuit and calculate the actual voltage according to the ratio of the voltages across the two ends.

[0117] The processor (113) has a gate voltage (V) in the inverter topology circuit. G1 , V G2 ) can be increased within a specified voltage range (e.g., from 0 V to 12 V) and then decreased within a specified voltage range (e.g., from 12 V to 0 V) ​​to check the change pattern of the voltage waveform.

[0118] Accordingly, as shown in Fig. 6, within the error range, the parasitic capacitor voltage (V) between the drain and source of a normal switching element C_DS ) If a change pattern of a voltage waveform such as a waveform is detected, the processor (113) can determine that the switching elements (Q12, Q14) of each inverter topology circuit are normal. If, within the error range, a change pattern of a different voltage waveform is detected, the processor (113) can determine that the switching elements (Q12, Q14) of each inverter topology circuit are short-circuited.

[0119] As described above, the processor (113) detects whether a switching element is short-circuited prior to the inverter's operation, enabling a response based on the detection of a short-circuit. Accordingly, secondary accidents and damage to peripheral circuits can be prevented in advance.

[0120] As described above, a short circuit in a switching element can be detected through 'powerless switching' in which only a gate voltage is applied to the switching element without power being applied to the power stage of the power conversion device.

[0121] Accordingly, a short circuit can be detected through power-free switching of the switching element (i.e., a short circuit is detected in advance before the operation of the switching element), so that damage to the component elements and peripheral circuits due to overcurrent can be prevented during operation in a short circuit state.

[0122] More specifically, when the power stage is in a power-free state (i.e., no power is applied to the power stage), and only the gate voltage is applied to the switching element of the power conversion device, the parasitic drain-source capacitance (CDS) voltage (V) of the switching element C_DS ) can be detected to detect short circuits.

[0123] Accordingly, a short circuit can be detected in advance before the switching element operates, thereby preventing additional secondary accidents and damage to peripheral circuits that may occur when an overcurrent is applied during a short circuit state of the switching element. In addition, since the configuration of the short circuit detection circuit is simpler than in the prior art, the circuit size and cost (e.g., costs required for cause analysis and fault response) can be reduced.

[0124] In addition, the present invention enables detection of a short circuit in advance through power-free switching of a switching element in a modular power conversion device (MLPE) and a power conversion device to which a micro inverter and a DC optimizer are applied, prior to the operation of the switching element, so that a short circuit of the switching element can be safely detected without concern of damage to components and peripheral circuits or occurrence of fire.

[0125] 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.).

[0126] While the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible. Accordingly, the technical protection scope of the present invention should be defined by the following claims.

[0127] 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). The apparatus may be implemented using suitable hardware, software, firmware, and the like. The 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 may also include a communication device such as a computer, a cell phone, a personal digital assistant ("PDA"), and other devices that facilitate communication of information between end-users.

Claims

1. In a power conversion device including a short circuit detection device of a switching element, The above paragraph detection device, A voltage application module that applies a gate voltage to a switching element; A voltage detection module for detecting the voltage of each terminal of the above switching element; and A processor for determining a short circuit of the switching element based on a waveform of a voltage detected through the voltage detection module according to application, increase, and decrease of a gate voltage to the switching element; The above power conversion device is a power conversion device that receives power from a solar module.

2. In paragraph 1, The above voltage application module, By continuously increasing the gate voltage by a specified or arbitrary unit, or A power conversion device that continuously reduces power by specified or arbitrary units.

3. In paragraph 1, The above voltage detection module, A power conversion device which detects the gate voltage of the switching element and the parasitic capacitor voltage between each terminal.

4. In paragraph 1, A power conversion device further comprising a storage module that stores information on a gate voltage waveform of a normal switching element and a parasitic capacitor voltage waveform according to application, increase, and decrease of a gate voltage.

5. In paragraph 1, The above processor, A power conversion device that compares the voltage waveform detected through the voltage detection module with the voltage waveform information of a normal switching element stored in advance in a storage module to determine a short circuit in the switching element.

6. In paragraph 5, The above processor, A power conversion device that determines that a short circuit in a switching element occurs when the change pattern of a voltage waveform detected through the voltage detection module differs by more than an error range from the voltage waveform information of a normal switching element stored in advance in the storage module.

7. In paragraph 1, The above processor, The above gate voltage is applied by dividing it into multiple sections, The change pattern of the voltage waveform between each terminal of the switching element detected in each of the above multiple sections is compared and analyzed with the change pattern of the voltage waveform of the normal switching element, A power conversion device that determines whether the switching element is short-circuited based on whether the results of the above comparative analysis are the same within the error range.

8. In paragraph 7, The above multiple sections are, A first section increasing from 0 V to the threshold voltage of the switching element; A second section increasing from the threshold voltage to the maximum voltage of the switching element; a third section decreasing from the maximum voltage to the threshold voltage; and A power conversion device comprising a fourth section decreasing from the above threshold voltage to 0 V.

9. In paragraph 8, The above processor, In the above first section, The above switching element is in the off state, and each parasitic capacitor (C) is turned on by the gate voltage. GS , C GD , C DS ) is fully charged, the parasitic capacitor (C) between drain and source DS ) is the peak voltage (V Peak ) is a power conversion device that compares and analyzes the change pattern of the voltage waveform charged to the switching element with the change pattern of the voltage waveform of the normal switching element.

10. In paragraph 8, The above processor, In the above second section, The above switching element is turned on, and the gate-source parasitic capacitor and the gate-drain parasitic capacitor (C GS Wow C GD ) is the gate voltage (V G ) increases in response to the increase in drain-source parasitic capacitor (C DS ) is a power conversion device that compares and analyzes the change pattern of the voltage waveform discharged through the turned-on switching element (Q1) with the change pattern of the voltage waveform of the normal switching element.

11. In paragraph 8, The above processor, In the third section above, When the above switching element is in the On state and the gate voltage decreases, the gate-source parasitic capacitor and the gate-drain parasitic capacitor (C GS Wow C GD ) is the gate voltage (V G ) is compared and analyzed with the change pattern of the voltage waveform of a normal switching element.

12. In paragraph 8, The above processor, In the above 4th section, As the above switching element is turned off, the drain-source parasitic capacitor (C) is momentarily DS ) is a power conversion device that compares and analyzes the change pattern of the voltage waveform in which the voltage of the switching element momentarily increases and then decreases to 0 V with the change pattern of the voltage waveform of a normal switching element.

13. A control method of a power conversion device for detecting a short circuit of a switching element, A step in which a processor of a short-circuit detection device of a switching element included in the above power conversion device applies a gate voltage to the switching element through a voltage application module; The step of the above processor detecting the voltage of each terminal of the switching element through the voltage detection module; and The above processor comprises a step of determining a short circuit of the switching element based on a waveform of a voltage detected through the voltage detection module according to application, increase, and decrease of a gate voltage to the switching element; A method in which the power conversion device receives power from a solar module.

14. In paragraph 13, The above voltage application module, By continuously increasing the gate voltage by a specified or arbitrary unit, or A method of continuously decreasing a specified unit or an arbitrary unit.

15. In paragraph 13, The above voltage detection module, A method for detecting a gate voltage of the switching element and a parasitic capacitor voltage between each terminal.

16. In paragraph 13, Before the step of determining the short circuit of the above switching element, A method further comprising: a step of pre-storing information on a gate voltage waveform of a normal switching element and a parasitic capacitor voltage waveform according to application, increase, and decrease of a gate voltage through a storage module; 17. In paragraph 13, The step of determining the short circuit of the above switching element is: A method for determining a short circuit in a switching element by comparing the voltage waveform detected through the voltage detection module with the voltage waveform information of a normal switching element previously stored in a storage module.

18. In paragraph 17, The step of determining the short circuit of the above switching element is: A method for determining a short circuit in a switching element when the change pattern of a voltage waveform detected through the voltage detection module differs by more than an error range from the voltage waveform information of a normal switching element stored in advance in the storage module.

19. In paragraph 13, The step of determining the short circuit of the above switching element is: A method of dividing the gate voltage into multiple sections and applying it, comparing and analyzing the change pattern of the voltage waveform between each terminal of the switching element detected in each section with the change pattern of the voltage waveform of a normal switching element, and determining whether the switching element is short-circuited based on whether they are the same within an error range.

20. A computer-readable recording medium having recorded thereon a program for executing the method of Article 13 on a computer.

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