Power conversion device

Abstract

A power conversion device according to one embodiment of the present invention comprises: an input unit for receiving power from a PV module; an initial driving unit for supplying an initial power source to a control unit by using the power input into the input unit; a power conversion unit for converting the power input into the input unit and outputting same; and a power source supply unit for supplying a power source to a control unit by using the output of the power conversion unit.

Description

power conversion device

[0001] The present invention relates to a power conversion device, and more specifically, to a power conversion device that supplies power to a control unit using input power.

[0002] Solar power generation is becoming widely adopted as an eco-friendly energy source, replacing conventional chemical and nuclear power generation. Solar power generation can be either standalone, with a battery connected to a converter, or grid-connected. Standalone systems typically consist of photovoltaic panels, storage batteries, and power conversion equipment, while grid-connected systems are connected to commercial power sources, enabling the exchange of power with load grid lines.

[0003] Photovoltaic modules have different maximum power points depending on factors such as irradiance and temperature. To operate solar cells at their maximum power point, an optimizer or module-level power electronics (MLPE) can be used to control maximum power point tracking (MPPT) at the module level and convert and output power.

[0004] The concept of MLPE configurations requiring installation on each photovoltaic module increases installation costs. New technologies, such as circuit simplification and device size reduction, are needed.

[0005] The technical problem to be solved by the present invention is to provide a power conversion device that supplies power to a control unit using input power.

[0006] In order to solve the above technical problem, a power conversion device according to one embodiment of the present invention includes an input unit for receiving power; an initial driving unit for supplying initial power to a control unit using the power input to the input unit; a power conversion unit for converting and outputting the power input to the input unit; and a power supply unit for supplying power to the control unit using the output of the power conversion unit.

[0007] In addition, the initial driving unit includes a first switching element connected to the input unit; and a switching element driving unit that turns on the first switching element using power input to the input unit, and when the first switching element is turned on, initial power can be supplied to the control unit through the first switching element.

[0008] Additionally, the first switching element can be turned off when power is supplied from the power supply unit to the control unit.

[0009] In addition, the power conversion unit includes a switching unit and a first passive component unit connected to the output side of the switching unit, and the switching unit can be PWM controlled by the control unit.

[0010] Additionally, the power supply unit may include a second passive component unit that is coupled to the first passive component unit when power is input to the first passive component unit and supplies power to the control unit.

[0011] Additionally, the first passive component unit may include a first winding, and the second passive component unit may include a second winding coupled with the first winding.

[0012] In addition, the power supply unit includes a first capacitor connected to the second winding; and a first diode connected to the first capacitor, and power induced in the second winding can be supplied to the control unit through the first capacitor and the first diode.

[0013] Additionally, when power is supplied from the power supply unit to the control unit, the initial driving unit can stop operation.

[0014] In addition, the initial driving unit includes a first switching element connected to the input unit; a first resistor connected in parallel with the first switching element in the input unit; a first zener diode connected in series with the first resistor; and a second resistor connected in series with the first switching element, wherein a first node between the first resistor and the first zener diode is connected to the gate of the first switching element, and when the first switching element is turned on, power input to the input unit through the first switching element and the second resistor can be supplied as an initial power source to the control unit.

[0015] Additionally, it may include a second diode connected to a second node between the first capacitor and the first diode; and a second zener diode and a second capacitor connected in parallel to a third node between the first diode and the output terminal of the initial driving unit.

[0016] According to embodiments of the present invention, power can be supplied to the control unit using input power without a separate auxiliary power supply. This reduces the number of controllers, magnetic components (inductors and filters), and semiconductor devices (FETs, diodes) for switch control, resulting in circuit simplification, reduced material costs, smaller device sizes, and improved product efficiency. Furthermore, EMC noise can be eliminated, improving communication quality and increasing design freedom.

[0017] Figure 1 is a block diagram of a power conversion device according to one embodiment of the present invention.

[0018] Figures 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention.

[0019] Figures 5 and 6 illustrate circuit diagrams of a power conversion device according to an embodiment of the present invention.

[0020] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0021] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0022] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0023] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0024] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0025] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0026] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0027] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0028] Variations according to the present embodiment may include some components of each embodiment and some components of other embodiments. That is, a variation may include one embodiment among various embodiments, but may omit some components and include some components of the corresponding other embodiment. Or, the opposite may be true. The features, structures, effects, etc. to be described in the embodiments are included in at least one embodiment, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified in other embodiments by a person having ordinary skill in the art to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included within the scope of the embodiments.

[0029] Fig. 1 is a block diagram of a power conversion device according to an embodiment of the present invention. Figs. 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention, and Figs. 5 and 6 illustrate circuit diagrams of a power conversion device according to an embodiment of the present invention.

[0030] A power conversion device (100) according to an embodiment of the present invention is composed of an input unit (110), an initial driving unit (120), a control unit (130), a power conversion unit (140), a power supply unit (150), and may include an output unit (160).

[0031] The power conversion device (100) according to an embodiment of the present invention is a power conversion device that receives power from a PV module (200), converts it, and outputs it, and may include an MLPE (Module-Level Power Electronics) of the PV module (200). Alternatively, it may include an optimizer. Alternatively, it may be a DC-DC converter or inverter that receives power from the PV module (200). Alternatively, it may include another power conversion device that receives power, converts it, and outputs it.

[0032] The input unit (110) receives power. The input unit (110) can receive power from a PV module (200).

[0033] A PV module (200) is a photovoltaic module, and may be a module that converts power generated by a photovoltaic panel or a photovoltaic panel into power suitable for a load or battery. It may be expressed as a solar module, solar power generation module, etc. A PV panel includes multiple cell strings. A solar cell that performs solar power generation may be expressed as a cell string unit in which multiple cells are connected in series.

[0034] A cell string may include at least one cell, and when including multiple cells, the multiple cells may be connected in series. The cell string may be a solar cell string including solar cells. The solar cell string may form a photovoltaic (PV) panel. A PV panel may also be referred to as a solar panel or solar power generation panel. Solar cells generate solar power (PV) by utilizing the photovoltaic effect. The photovoltaic effect is the emission of electrons when light above a certain frequency strikes a specific metal material. A pn ​​junction is formed using a p-type semiconductor and an n-type semiconductor, and the electrons generated by the photovoltaic effect are used to generate current, thereby generating power. Solar cells are formed using silicon or other materials and may be formed in a wafer form. Solar cells are located in fields that can receive a lot of sunlight, on the exterior walls of buildings, on rooftops, etc., and generate power using sunlight. In this case, the solar cells may be formed as BIPV (Building Integrated Photovoltaics) that are formed integrally with the building.

[0035] Since the amount of power generated from a single solar cell is insufficient to be utilized by a load or power system, power suitable for utilization can be generated by connecting multiple solar cells in series to form a solar cell string instead of a single solar cell. A solar cell string can be a basic unit for generating power. A photovoltaic panel can be formed by forming multiple cell strings, which are basic units, into a panel. Solar cells have different voltage-current characteristics depending on the amount of sunlight, temperature, etc., and the maximum power point (MPP) also changes. (Generated power = Voltage X Current)

[0036] The control unit (130) may control the solar cell to operate at the maximum power point (MPP), which is the operating point where the power of the solar cell is maximum under each condition. This is called maximum power point tracking (MPPT), and the efficiency of solar power generation can be increased by using MPPT tracking. In solar power generation, depending on the characteristics of the relationship between current and voltage and the relationship between voltage and power, the maximum power may be the power when the voltage is about 80% of the maximum voltage, not the maximum voltage. Since this maximum power point continuously changes depending on the magnitude of the voltage and current generated by the photovoltaic panel, the point where the maximum power point can be generated must be continuously searched. That is, in order to track the maximum power, not the maximum voltage, the magnitude of the voltage and current can be varied so as to achieve the maximum power. That is, the voltage can be reduced and the current can be increased in the direction of increasing power, or the voltage can be increased and the current can be reduced.

[0037] The power input to the input unit (110) can be converted and output by the power conversion unit (140). The power conversion unit (140) can supply power to the grid via an energy storage system (ESS) including a battery or an inverter through the output unit (160). A DC-Link can be connected to the output unit (160).

[0038] The power conversion unit (140) includes a switching unit (141), and in order to control the operation of the switching unit (141), the control unit (130) must apply a PWM signal to the switching unit (141). In order for the control unit (130) to operate the power conversion unit (140), the control unit (130) must first be driven. In order to drive the control unit (130), driving power must be supplied to the control unit (130), and in order to supply driving power to the control unit (130), the power conversion device (100) according to the embodiment of the present invention may include an initial driving unit (120) and a power supply unit (150). The initial driving unit (120) and the power supply unit (150) may be included so that power input to the input unit (110) can be directly used without implementing a separate auxiliary power circuit for supplying power to the control unit (130).

[0039] The initial driving unit (120) supplies initial power to the control unit (130) using the power input to the input unit (110). When the control unit (130) is not operating and power is input to the input unit (110), the initial driving unit (120) can supply initial power to the control unit (130) using the power input to the input unit (110). The initial driving unit (120) can operate as a start circuit.

[0040] The initial driving unit (120) may include a first switching element (121) and a switching element driving unit (122). The first switching element (121) is connected to the input unit (110), and the switching element driving unit (122) may turn on the first switching element (121) using power input to the input unit (110). When the first switching element (121) is turned on, initial power may be supplied to the control unit (130) through the first switching element (121).

[0041] The first switching element (121) can connect or disconnect a path for transmitting power from the input unit (110) to the control unit (130). The first switching element (121) may include a MOSFET, which is a semiconductor switch, and may include various types of switching elements, such as a relay.

[0042] The switching element driver (122) can turn off the first switching element (121). The switching element driver (122) can operate with power input to the input unit (110), and when power is input to the input unit (110), the switching element driver (122) can supply driving power to the first switching element (121) to turn on the first switching element (121). The first switching element (121) can be a MOSFET, and the first switching element (121) can supply gate power to the first switching element (121) to turn on the first switching element (121). When the first switching element (121) is turned on, a path connecting the input unit (110) to the control unit (130) is formed, so that initial power can be supplied to the control unit (130).

[0043] The initial driving unit (120) may include a first switching element (121) connected to the input unit (110), a first resistor (R1) connected in parallel with the first switching element (121) to the input unit (110), a first zener diode (Z1) connected in series with the first resistor (R1), and a second resistor (R2) connected in series with the first switching element (121). Here, a first node (N1) between the first resistor (R1) and the first zener diode (Z1) is connected to the gate of the first switching element (121), and when the first switching element (121) is turned on, power input to the input unit (110) through the first switching element (121) and the second resistor (R2) may be supplied as initial power to the control unit (130).

[0044] The power conversion unit (140) converts and outputs power input to the input unit (110). The power conversion unit (140) operates under the control of the control unit (130) to convert and output power input to the input unit (110). The power output from the power conversion unit (140) can be provided to a DC-DC converter, a DC link, a battery, a grid, a load, etc. through the output unit (160).

[0045] The power conversion unit (140) may include a switching unit (141) and a first passive component unit (142). The first passive component unit (142) may be connected to the output side of the switching unit (141).

[0046] The power conversion unit (140) includes a switching unit (141) to convert power input to the input unit (110), and the switching unit (141) includes one or more switching elements, and the switching elements included in the switching unit (141) can be PWM (pulse width modulation) controlled by the control unit (130).

[0047] The switching unit (141) may include at least one upper switch and at least one lower switch, and a first passive element unit (142) may be connected to a node between the first upper switch and the first lower switch. The first upper switch and the first lower switch may include a MOSFET, which is a semiconductor switch, and may include various types of switching elements such as a relay. The control unit (130) may control the power applied to the first passive element unit (142) by supplying PWM power to the gate power of the first upper switch and the first lower switch, which are MOSFETs.

[0048] The switching unit (141) may include a first upper switch and a first lower switch connected to the input unit (110), a second upper switch and a second lower switch connected to the output unit (160), a first passive component connected between a node between the first upper switch and the first lower switch, and a node between the second upper switch and the second lower switch. The control unit (130) may supply PWM power to the gate power of the first upper switch, the first lower switch, the second upper switch, and the second lower switch, which are MOSFETs, to control the power applied to the first passive component or output from the first passive component.

[0049] A power conversion device (100) according to an embodiment of the present invention may be an MLPE of a PV module (200), and a control unit (130) may control a switching unit (141) to perform maximum power point tracking control for the PV module (200). A first passive component unit (142) may operate according to power input from the switching unit (141) and output to an output unit (160). The switching unit (141) and the first passive component unit (142) may operate as a buck type, a buck-boost type, or a boost type converter. The first passive component unit (142) may be an inductance element, an inductor, or a winding coupled with a second passive component unit (151) of a power supply unit (150).

[0050] The power supply unit (150) supplies power to the control unit (130) using the output of the power conversion unit (140). The initial driving unit (120) supplies initial power to the control unit (130), and when the control unit (130) operates to control the power conversion unit (140) and power is converted and output from the power conversion unit (140), the power supply unit (150) can supply power to the control unit (130) using the power output from the power conversion unit (140).

[0051] The power supply unit (150) may include a second passive component unit (151) that is coupled with the first passive component unit (142) when power is input to the first passive component unit (142) and supplies power to the control unit (130). The power supply unit (150) may include a first capacitor (C1) and a first diode (D1).

[0052] The power supply unit (150) may use induced electromotive force to supply power output from the power conversion unit (140) to the control unit (130). It may include a second passive element unit (151) coupled with the first passive element unit (142) so that power is induced by the induced electromotive force when power is input to the first passive element unit (142). The first passive element unit (142) may include a first winding, and the second passive element unit (151) may include a second winding coupled with the first winding. The first passive element unit (142) and the second passive element unit (151) may form a transformer (170) shape, and may supply power induced from power input to the first passive element unit (142) to the control unit (130).

[0053] The power supply unit (150) may include a first capacitor (C1) connected to a second passive component unit (151) and a first diode (D1) connected to the first capacitor (C1). The power induced in the second winding, which is the second passive component unit (151), may be adjusted by the first capacitor (C1) to the power input to the control unit (130), and may be input to the control unit (130) via the first capacitor (C1) and the first diode (D1).

[0054] When power is supplied from the power supply unit (150) to the control unit (130), the initial driving unit (120) can stop operating. The initial driving unit (120) supplies initial power to the control unit (130), but the initial driving unit (120) is connected to the input unit (110) side and may consume power, which may reduce power efficiency. The initial driving unit (120) may include a first resistor (R1) and a second resistor (R2), and power may be consumed in the resistors. In order to prevent continuous power consumption of the initial driving unit (120), when power is supplied from the power supply unit (150) to the control unit (130), the initial driving unit (120) can stop operating. When power is supplied from the power supply unit (150) to the control unit (130), the first switching element (121) may be turned off.

[0055] The first diode (D1) of the power supply unit (150) is connected in parallel with the second resistor (R2), which is the output terminal of the initial driving unit (120), and when power is induced from the power supply unit (150), the potential of the power input from the power supply unit (150) and the potential of the switching element driving unit (122) become the same, so that the driving power is not applied from the switching element driving unit (122) to the first switching element (121), and the first switching element (121) is turned off, so that the initial driving unit (120) can stop supplying power. That is, the first switching element (121) of the initial driving unit (120) is turned on when the initial power is supplied, and is turned off when the power supply unit (150) operates, thereby preventing power consumption.

[0056] A second diode (D2) may be connected to a second node (N2) between a first capacitor (C1) and a first diode (D1), and a second zener diode (Z2) and a second capacitor (C4) may be connected in parallel to a third node (N3) between the first diode (D1) and a second resistor (R2), which is an output terminal of the initial driving unit (120). An input capacitor (C2) and an output capacitor (C3) may be connected to the input unit (110) and the output unit (160), respectively.

[0057] If no power is input to the input unit (110), no power is output from the power conversion unit (140), and the power supply unit (150) also stops operating, so that no power is supplied to the control unit (130), and thus the control unit (130) can stop operating. Thereafter, if power is input to the input unit (110) again, the power conversion device can operate in the following order: operation of the initial driving unit (120), operation of the control unit (130), operation of the power conversion unit (140), operation of the power supply unit (150), and stop of the initial driving unit (120).

[0058] A power conversion device according to an embodiment of the present invention can be implemented with the circuit diagram of Fig. 5 or Fig. 6. Fig. 5 is a circuit diagram of a power conversion device having a buck type topology, and Fig. 6 is a circuit diagram of a power conversion device having a buck-boost type topology.

[0059] A power conversion device having a buck type topology can be implemented as shown in Fig. 5.

[0060] When power is applied to the input unit (110), power is applied to the first resistor (R1) and the first Zener diode (Z1), and gate power is applied to the first switching element (Q1) through the first node between the first resistor (R1) and the first Zener diode (Z1), so that the first switching element (Q1) can be turned on. The first switching element (Q1) is connected to the input unit (110) in parallel with the first resistor (R1), and when turned on, the initial power Vcc can be input to the control unit (130) through the second resistor (R2). The power conversion unit (140) connected to the input unit (110) may include a first upper switch (Q2), a first lower switch (Q3), and a first passive element unit connected to a node between the first upper switch (Q2) and the first lower switch (Q3). The first passive component unit can be coupled with the second passive component unit of the power supply unit to form a transformer (T) to induce power. The power induced in the transformer (T) can be input as a power source Vcc to the control unit (130) through the first capacitor (C1) and the first diode (D1). Here, a second diode (D2) is connected to the second node (N2) between the first capacitor (C1) and the first diode (D1), and a second zener diode (Z2) and a second capacitor (C4) connected in parallel to the third node (N3) between the first diode (D1) and the second resistor (R2), which is an output terminal of the initial driving unit (120) can be included. An input capacitor (C2) and an output capacitor (C3) can be connected to the input unit (110) and the output unit (160), respectively. When power is induced from the power supply unit (150), the potential of the power input from the power supply unit (150) and the potential of the switching element driving unit (122) become the same, so that the driving power is not applied from the switching element driving unit (122) to the first switching element (121), and the first switching element (121) is turned off, so that the initial driving unit (120) can stop supplying power.

[0061] A power conversion device having a buck-boost type topology can be implemented as shown in Fig. 6.

[0062] When power is applied to the input unit (110), power is applied to the first resistor (R1) and the first Zener diode (Z1), and gate power is applied to the first switching element (Q1) through the first node between the first resistor (R1) and the first Zener diode (Z1), so that the first switching element (Q1) can be turned on. The first switching element (Q1) is connected to the input unit (110) in parallel with the first resistor (R1), so that when turned on, the initial power Vcc can be input to the control unit (130) through the second resistor (R2). The power conversion unit (140) connected to the input unit (110) includes a first upper switch (Q2) and a first lower switch (Q3), a first passive component unit (142) connected to a node between the first upper switch (Q2) and the first lower switch (Q3), a second upper switch (Q4) and a second lower switch (Q5) connected to the output unit (160), and the first passive component unit (142) can be connected to a node between the second upper switch (Q4) and the second lower switch (Q5). The first passive component unit (142) can be coupled to the second passive component unit (151) of the power supply unit to form a transformer (T) to induce power. The power induced in the transformer (T) can be input to the control unit (130) as a power source Vcc through the first capacitor (C1) and the first diode (D1). Here, a second diode (D2) may be connected to a second node (N2) between a first capacitor (C1) and a first diode (D1), and a second zener diode (Z2) and a second capacitor (C4) may be connected in parallel to a third node (N3) between the first diode (D1) and a second resistor (R2), which is an output terminal of an initial driving unit (120). An input capacitor (C2) and an output capacitor (C3) may be connected to the input unit (110) and the output unit (160), respectively.When power is induced from the power supply unit (150), the potential of the power input from the power supply unit (150) and the potential of the switching element driving unit (122) become the same, so that the driving power is not applied from the switching element driving unit (122) to the first switching element (121), and the first switching element (121) is turned off, so that the initial driving unit (120) can stop supplying power.

[0063] As described above, by configuring a power conversion device (100) according to an embodiment of the present invention, a separate controller for switch control, magnetic components (inductors and filters), and semiconductor devices (FETs, diodes) can be reduced, thereby achieving effects such as reducing material costs and reducing the size of the device through circuit simplification, and improving product efficiency. In addition, since a separate auxiliary power supply for generating driving power for the control unit (130) is not required, switching elements can be reduced, thereby eliminating EMC noise, improving communication quality, and increasing design freedom.

[0064] 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 description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. Input section for receiving power; An initial driving unit that supplies initial power to the control unit using power input to the above input unit; A power conversion unit that converts and outputs power input to the input unit; and A power conversion device including a power supply unit that supplies power to the control unit using the output of the power conversion unit.

2. In paragraph 1, The above initial driving part, a first switching element connected to the input section; and It includes a switching element driving unit that turns on the first switching element by using power input to the input unit, A power conversion device in which initial power is supplied to the control unit through the first switching element when the first switching element is turned on.

3. In paragraph 2, The above first switching element, A power conversion device that is turned off when power is supplied from the above power supply unit to the above control unit.

4. In paragraph 1, The above power conversion unit, switching unit; and Including a first passive component unit connected to the output side of the above switching unit, The above switching unit is a power conversion device that is PWM controlled by the above control unit.

5. In paragraph 4, The above power supply unit, A power conversion device including a second passive component unit that is coupled with the first passive component unit when power is input to the first passive component unit and supplies power to the control unit.

6. In paragraph 5, The above first passive component includes a first winding, A power conversion device wherein the second passive component includes a second winding coupled with the first winding.

7. In paragraph 6, The above power supply unit, a first capacitor connected to the second winding; and comprising a first diode connected to the first capacitor; A power conversion device in which power induced in the second winding is supplied to the control unit through the first capacitor and the first diode.

8. In paragraph 1, A power conversion device in which, when power is supplied from the power supply unit to the control unit, the initial driving unit stops operating.

9. In paragraph 1, The above initial driving part, A first switching element connected to the above input unit; A first resistor connected in parallel with the first switching element in the input section; a first zener diode connected in series with the first resistor; and comprising a second resistor connected in series with the first switching element; A first node between the first resistor and the first zener diode is connected to the gate of the first switch element, A power conversion device in which, when the first switching element is turned on, power input to the input section through the first switching element and the second resistor is supplied as initial power to the control section.

10. In paragraph 7, a second diode connected to a second node between the first capacitor and the first diode; and A power conversion device including a second zener diode and a second capacitor connected in parallel to a third node between the first diode and the output terminal of the initial driving unit.

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