Power transmission device

Abstract

A power transmission device according to one embodiment of the present invention comprises: a PV module connection unit that receives power input from a PV module; a battery connection unit connected to the battery to output power to the battery or receive power input from the battery; an inverter connection unit connected in parallel to the battery connection unit, and outputting power to an inverter when connected to the inverter; and a control unit controlling the PV module by communicating with the PV module, and controlling the battery connection unit and the inverter connection unit to output power input from the PV module to the battery or the inverter.

Description

Technical Field

[0001] The present invention relates to a power transmission device, and more particularly, to a power transmission device that efficiently transmits power from a solar power generation module to a battery or an inverter. Background Art

[0002] Solar power generation is an environmentally friendly alternative to existing chemical or nuclear power generation. Solar power generation includes standalone systems, where batteries are connected to a converter, and grid-connected systems, where batteries are connected to the grid. Standalone systems typically consist of solar cells, storage batteries, and power conversion equipment, while grid-connected systems connect to commercial power, allowing them to exchange power with the load grid.

[0003] The maximum power point of a photovoltaic module varies depending on the amount of sunlight, temperature, etc. To operate the solar cells at their maximum power point, an optimizer or module-level power electronics (MLPE) that performs maximum power point tracking (MPPT) control on a module-by-module basis may be used.

[0004] When the output of the photovoltaic module is stored in the battery module, it is charged to the battery through two power conversions: the photovoltaic module's optimizer and the battery module's battery DC-DC converter. At this time, the optimizer, which is configured in a 1:1 series configuration with the photovoltaic module, must be controlled to an appropriate DC (400V level) voltage for battery charging / discharging and the inverter output must be connected to the load. This complicates control and leads to excessive battery discharge when the solar power generation system is not operating for a long time due to reasons such as user vacation or system failure. Summary of the Invention

[0005] Technical issues

[0006] The technical problem to be solved by the present invention is to provide a power transmission device that effectively transmits power from a solar power generation module to a battery or an inverter, and a solar power generation system including the power transmission device.

[0007] Technical Solution

[0008] According to one embodiment of the present invention, a power transmission device includes: a PV module connection unit, which receives power input from a PV module; a battery connection unit, which is connected to a battery to output power to the battery or receive power input from the battery; an inverter connection unit, which is connected to the battery connection unit in parallel and outputs power to the inverter when connected to the inverter; and a control unit, which controls the PV module by communicating with the PV module, and controls the battery connection unit and the inverter connection unit to output power input from the PV module to the battery or the inverter.

[0009] Furthermore, a power line communication unit that performs communication with the PV module through a power line electrically connected to the PV module may be included.

[0010] Furthermore, the PV module includes an optimizer, and the control unit may send a control signal to the optimizer through the power line communication unit.

[0011] Furthermore, the PV module includes a plurality of PV modules, and the plurality of PV modules may be connected in parallel to the PV module connection unit.

[0012] Furthermore, the PV module includes a plurality of PV modules, and the plurality of PV modules may be connected in series.

[0013] Furthermore, an abnormality detection unit may be included that detects whether an abnormality exists in the PV module.

[0014] Furthermore, an RSD unit may be included that reduces the voltage of the PV module below a first value when an abnormality in the PV module is detected.

[0015] In addition, it may include: an input current sensing unit, which is used to measure the input current of the power input to the PV module connection unit; an output voltage sensing unit, which is used to measure the output voltage of the power output to at least one of the battery connection unit and the inverter connection unit; and an output current sensing unit, which is used to measure the output current of the power output to the inverter connection unit.

[0016] Furthermore, the battery may include: a first switching unit that connects or disconnects the battery; and an initial charging unit that performs initial charging when connected to the battery.

[0017] Furthermore, a communication unit that performs communication with a battery management device that manages the battery may be included.

[0018] Furthermore, it may include: a second switching unit for connecting or disconnecting the inverter; and a bypass unit for forming a bypass path on the inverter connecting unit when the connection with the inverter connecting unit is disconnected according to the operation of the second switching unit.

[0019] Furthermore, the inverter connection unit may be connected in series with an inverter connection unit of another power transmission device.

[0020] In order to solve the above technical problems, the power transmission device according to an embodiment of the present invention includes: a PV module connection unit, the PV module connection unit is connected to the output of the PV module; a power line communication unit, the power line communication unit is connected to the (+) power line of the PV module connection unit and communicates with the PV module; an abnormality detection unit, the abnormality detection unit is connected to the (-) power line of the PV module connection unit and detects abnormalities of the PV module; an input current sensing unit, the input current sensing unit measures the current of the (+) power line of the PV module connection unit; a first diode, the first diode is connected to the (+) power line of the PV module connection unit and blocks the current flowing to the PV module; a battery connection unit, the battery connection unit is connected to the battery and outputs power to the battery or receives power from the battery receiving and receiving power; an inverter connection unit, the inverter connection unit is connected in parallel with the battery connection unit and outputs power to the inverter when connected to the inverter; an output current sensing unit, the output current sensing unit measures the output voltage of the front end of the node to which the battery connection unit and the inverter connection unit are connected; a first switch unit, the first switch unit is connected to the (+) power line of the battery connection unit and connects or disconnects the battery; the output current sensing unit, the output current sensing unit measures the current of the (+) power line of the inverter connection unit; a second switch unit, the second switch unit is connected to the (-) power line of the inverter connection unit and connects or disconnects the inverter; and a bypass unit, the bypass unit is connected to the (+) power line and the (-) power line of the inverter connection unit and forms a bypass path.

[0021] Furthermore, the PV module connection unit may include an RSD unit that is connected between the (+) power line and the (−) power line and reduces the voltage of the PV module below a first value when an abnormality in the PV module is detected.

[0022] Furthermore, a first capacitor connecting the (+) power line and the (−) power line at the front end of the node to which the battery connection unit and the inverter connection unit are connected may be included.

[0023] Beneficial effects

[0024] According to an embodiment of the present invention, PV-generated power can be used to charge a battery without passing through a PV DC-DC converter and a battery DC-DC converter, thereby improving the efficiency of charging the battery module from the PV module. In addition, the DC link voltage can be formed by the voltage of the battery, making it easy to control the system, the battery can be separated and operated in the event of a fault, the battery can be charged even when the system is shut down, and balancing between the batteries can also be easily achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram of a power transmission apparatus according to an embodiment of the present invention.

[0026] Figure 2 FIG. 1 shows the connection relationship between the various components of the power transmission device according to the embodiment of the present invention.

[0027] Figure 3 An implementation example of a power transmission device according to an embodiment of the present invention is shown.

[0028] Figures 4 to 9 It is a diagram for explaining various connection relationships between the power transmission device according to the embodiment of the present invention and other devices. DETAILED DESCRIPTION

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] However, the technical concept of the present invention is not limited to some embodiments to be described, but can be implemented in various forms, and within the scope of the technical concept of the present invention, one or more constituent elements can be selectively combined or replaced between the embodiments.

[0031] In addition, unless explicitly defined and described, the terms (including technical terms and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that can be generally understood by those skilled in the art, and common terms such as terms defined in dictionaries may be interpreted considering the meaning of the context of the relevant technology.

[0032] In addition, the terms used in this specification are used to describe the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specified in the wording, a singular form may include a plural form, and when described as "at least one (or more than one) of A, B, and C", it may include one or more of all possible combinations of A, B, and C.

[0033] Furthermore, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

[0034] These terms are only intended to distinguish a component from other components, and these terms do not limit the nature, sequence, or order of the components.

[0035] In addition, when a component is described as being “connected,” “coupled” or “interconnected” to another component, the component is not only directly connected, coupled or interconnected to another component, but also includes the case where the component is “connected,” “coupled” or “interconnected” due to another component between the components.

[0036] Furthermore, when describing that a component is formed or disposed “on (above)” or “under (below)”, “on (above)” or “under (below)” is intended to include not only a case where two components are in direct contact but also a case where one or more other components are formed or disposed between the two components. Furthermore, when expressed as “on (above)” or “under (below)”, its meaning may include not only an upward direction relative to a component but also a downward direction relative to the component.

[0037] Figure 1 is a block diagram of a power transmission apparatus according to an embodiment of the present invention. Figure 2 FIG. 4 shows the connection relationship between the various components of the power transmission device according to an embodiment of the present invention. Figure 3 FIG. 4 shows an implementation example of a power transmission device according to an embodiment of the present invention. Figures 4 to 9 It is a diagram for explaining various connection relationships between the power transmission device according to the embodiment of the present invention and other devices.

[0038] According to an embodiment of the present invention, the power transmission device 100 is configured with a PV module connection unit 101, a battery connection unit 102, an inverter connection unit 103 and a control unit 104, and may include a power line communication unit 111, an input current sensing unit 112, a reverse current blocking unit 113, an output voltage sensing unit 114, an output current sensing unit 115, a first switching unit 116, a second switching unit 117, a bypass unit 118, an abnormality detection unit 119, an RSD unit 120, a smoothing unit 121, and the like.

[0039] The power transmission device 100 according to an embodiment of the present invention is a device that can effectively transmit power between the PV module 210, the battery 220, and the inverter 230, and acts as a hub, so it can be called an energy hub. In addition, the power transmission device 100 according to an embodiment of the present invention can form a battery module with the battery 220, a PV module with the PV module 210, or an inverter module with the inverter 230. In addition, the power transmission device 100 according to an embodiment of the present invention can form a PV battery module together with the battery 220 and the PV module 210, or form a PV inverter module together with the inverter 230 and the PV module 210. In addition, it can form a solar power generation system together with the PV module 210, the battery 220, and the inverter 230.

[0040] To this end, the power transmission device 100 according to an embodiment of the present invention can perform various functions such as communication, PV module control, battery blocking, bypass, battery monitoring, arc detection, RSD function, etc. Hereinafter, the power transmission device 100 according to an embodiment of the present invention will be described in detail.

[0041] The PV module connection unit 101 is connected to the PV module 210 and receives power from the PV module 210 .

[0042] The PV module 210 generates electricity using sunlight through solar power generation. It may include a PV panel 211 and an optimizer 212. The optimizer 212 may perform maximum power point tracking (MPPT) so that the power output from the PV panel 211 is the maximum power.

[0043] PV panel 211 may include multiple cell strings. A solar cell that performs solar power generation can be described as a cell string unit in which multiple cells are connected in series. A cell string may include at least one cell, and when it includes multiple cells, the multiple cells may be connected in series. A cell string may be a solar cell string including solar cells. A solar cell string may form a PV panel. PV panel 211 may also be referred to as a solar panel or a solar power generation panel. Solar cells generate electricity by generating photovoltaic power (PV) using the photovoltaic effect. The photovoltaic effect is a phenomenon in which electrons are emitted when light of a specific frequency or higher strikes a specific metal material, and a PN junction is formed using a p-type semiconductor and an n-type semiconductor, generating electricity by using the electrons generated by the photovoltaic effect to generate current. Solar cells are formed using silicon or the like and may be formed in a wafer shape. The solar cell is located in a location where it can receive a large amount of sunlight, such as a site, the exterior walls of a building, or the roof, and generates electricity using the sunlight. In this case, the solar cell may be formed as a building-integrated photovoltaic (BIPV) (photovoltaic formed as an integral part of the building).

[0044] Since the amount of electricity generated from a single solar cell is insufficient for use in a load or power system, a suitable amount of electricity can be generated by connecting multiple solar cells in series to form a solar cell string rather than a single solar cell. A solar cell string can be a basic unit for power generation. A photovoltaic panel can be formed by forming multiple cell strings as basic units into panels. 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 × current).

[0045] PV module 210 may include multiple PV modules. Each PV module includes a PV panel 211 and an optimizer 212. Multiple optimizers 212 are connected to the output power of each cell string and can be connected in series or parallel. The optimizer optimizes the output power of the cell string so that the solar cells operate at their maximum power point (MPP), which is the point at which the solar cells' power reaches its maximum under certain conditions. The optimizer may include module-level power electronics (MLPE). This is known as maximum power point tracking (MPPT), and using MPPT can improve the efficiency of solar power generation. In solar power generation, depending on the relationship between current and voltage, and between voltage and power, the maximum power can be approximately 80% of the maximum voltage, rather than the power at maximum voltage. Because this maximum power point continuously changes depending on the voltage and current generated by the PV panel, it is necessary to continuously find the point at which the maximum power point is likely to occur. In other words, to achieve maximum power rather than maximum voltage, the voltage and current can be varied to achieve maximum power. In other words, to increase power, the voltage can be reduced and the current increased, or the voltage can be increased and the current reduced.

[0046] When connected to the inverter 230, the inverter connection unit 103 outputs power to the inverter 230. At this time, the inverter connection unit 103 is connected in parallel with the battery connection unit 102. When connected to the inverter 230, the power input from the PV module 210 can be output to the inverter 230 through the inverter 230 or the DC-DC converter 240 connected to the inverter 230.

[0047] The inverter 230 can supply the power output from the inverter connection unit 103 to the load or the grid. The inverter 230 can receive the DC power output from the inverter connection unit 103, convert it into AC power, and supply power to the load or the grid. It can supply AC power to a load that requires AC power and transmit the remaining power to the grid, i.e., the system. Alternatively, it can receive AC power from the grid, convert it into DC power, and output it to a power transmission device. Here, the inverter 230 may include a DC-AC inverter. A separate power generation device (such as a diesel generator that can generate and supply electricity when the power supplied to the load is insufficient) can be connected to the inverter 230, and a circuit breaker that can cut off the connection to the grid and an energy meter that measures the power supplied or provided from the grid can be connected. When the connection to the grid is cut off, the entire system except the grid can be switched to independent operation.

[0048] The battery connection unit 102 is connected to the battery 220 and outputs power to the battery 220 or receives power from the battery 220. The power input from the PV module 210 through the PV module connection unit 101 is transmitted to the inverter 230 through the inverter connection unit 103, and the battery 220 can be charged and discharged through the battery connection unit 102. The battery 220 may include a battery management system (BMS) that manages the battery status.

[0049] The control unit 104 controls the PV module 210 by communicating with the PV module 210, and controls the battery connection unit 102 and the inverter connection unit 103 to output the power input from the PV module 210 to the battery 220 or the inverter 230. The control unit 104 measures input current, output voltage, output current, etc., and receives data including status information from the PV module 210, the battery 220, the inverter 230, an external controller, a load, etc., and controls each configuration so that the power input from the PV module 210 can be output to the inverter 230 or the battery 220.

[0050] Naturally, the control unit 104 includes one or more processors and may also include a memory, and the functions of the control unit 104 or other components may be implemented in software or hardware.

[0051] When outputting the power received from the PV module 210 to the inverter 230 or the battery 220, the power transmission device 100 according to an embodiment of the present invention may include a power line communication unit 111, an input current sensing unit 112, a reverse current blocking unit 113, an output voltage sensing unit 114, an output current sensing unit 115, a first switching unit 116, a second switching unit 117, a bypass unit 118, an abnormality detection unit 119, an RSD unit 120, a smoothing unit 121, etc. As an example, the various components may be configured as follows: Figure 2 shown.

[0052] The power line communication unit 111 can communicate with the PV module 210 via a power line electrically connected to the PV module 210. The PV module connection unit 101 may include a (+) power line 122 and a (-) power line 123, and the power line communication unit 111 can be connected to the (+) power line 122 of the PV module connection unit 101 to communicate with the PV module 210. In this case, the power line communication unit 111 may implement power line communication (PLC), which uses power lines for communication. Alternatively, communication may be performed via wired or wireless communication other than the PV module 210. The control unit 104 controls the power line communication unit 111 to communicate with the PV module 210 via PLC communication to receive information from the PV module 210 or control the power of the PV module 210. In this case, the power line communication unit 111 can communicate with the optimizer 212 of the PV module 210. The control unit 104 can send a control signal to the optimizer 212 via the power line communication unit 111 to control the power output from the PV module 210. The control may be performed by sending a signal for turning the optimizer 212 on and off or a signal for controlling the amount of output power.

[0053] The PV module 210 may include a plurality of PV modules, and the plurality of PV modules may be connected in parallel to the PV module connection unit. The plurality of PV modules 210 may be connected in parallel, such as Figure 4 Alternatively, multiple PV modules can be connected in series, as shown in Figure 6 shown.

[0054] When charging battery 220 by receiving power from multiple PV modules 210, when the battery voltage is low, battery 220 can be fully charged with a single PV module, so multiple PV modules 210 can be connected in parallel. Since multiple PV modules 210 are connected in parallel, battery 220 can be fully charged even if a problem occurs in some of the multiple PV modules 210. When the battery voltage is high, it may be difficult to charge the battery with the voltage of a single PV module 210. In this case, the PV modules can be connected in series to form a large voltage input to PV module connection unit 101. That is, multiple PV modules can be connected in parallel or in series, depending on the applied battery voltage.

[0055] The abnormality detection unit 119 can detect whether an abnormality exists in the PV module 210. It can detect an arc or the like that may affect the PV module 210. An arc is a phenomenon in which a current flows through a non-conductive medium such as air through a gas insulation breakdown. When an arc occurs, a large amount of heat is generated, posing a risk of fire, etc. The abnormality detection unit 119 can detect the occurrence of an arc or the like by including an arc sensor or the like. The abnormality detection unit 119 can be connected to the (-) power line 123 of the PV module connection unit.

[0056] When an abnormality is detected in the PV module 210, the RSD unit 120 can reduce the voltage of the PV module 210 to below the first value. When an abnormality is detected in the status information received from the PV module 210, or when a fire risk occurs, or when an RSD operation command is received from the abnormality detection unit 119 or the outside, the RSD unit 120 can perform a rapid shutdown (RSD) function to quickly stop the PV module 210. For the RSD operation, a resistor that consumes power and a switch connecting the resistor may be included. By consuming power through the resistor, the voltage of the PV module 210 can be reduced to below the first value in a short period of time, thereby ensuring safety. When the RSD function is included in the optimizer 212 of the PV module 210, the RSD unit 120 may not be applied or the RSD unit 120 may be applied to the RSD function of the optimizer 212 as redundancy, thereby improving safety.

[0057] In order to monitor the input / output of power, an input current sensing unit 112 , an output voltage sensing unit 114 , and an output current sensing unit 115 may be included.

[0058] The input current sensing unit 112 can measure the input current of the power input to the PV module connection unit. The input current sensing unit 112 is connected to the (+) power line 122 of the PV module connection unit and can measure the input current. The input current sensing unit 112 can be configured with a current sensor such as Figure 3 shown.

[0059] The output voltage sensing unit 114 can measure the output voltage of the power output from at least one of the battery connection unit 102 and the inverter connection unit 103. The output voltage can be measured, which is the voltage at the front end of the node of the battery connection unit 102 and the inverter connection unit 103 connected in parallel. The output voltage sensing unit 114 can be configured with a voltage sensor such as Figure 3 The control unit 104 may calculate the power generation amount of the PV module 210 by using the current measured by the input current sensing unit 112 and the output voltage measured by the output voltage sensing unit 114 .

[0060] The reverse current blocking unit 113 and the smoothing unit 121 may be included between the input current sensing unit 112 and the output voltage sensing unit 114. The reverse current blocking unit 113 may prevent current from being applied from the battery 220 or the inverter 230 to the PV module 210. Thus, the safety of the PV module 210 may be improved. The reverse current blocking unit 113 may include a first diode, such as Figure 3 As shown. By utilizing the characteristics of the diode, current can flow from the PV module connection unit 101 to the battery 220 or the inverter 230, and reverse current flowing in the opposite direction can be blocked. The smoothing unit 121 can play a role in stabilizing the power input from the PV module 210. The power generation of the PV module 210 is affected by the external environment, and due to the occurrence of noise, etc., it may not be possible to supply stable power to the inverter 230 or the load. In order to remove such unstable signals or noise, etc., the smoothing unit 121 can be connected. The smoothing unit 121 may include a first capacitor, which is a smoothing capacitor, such as Figure 3 shown.

[0061] The output current sensing unit 115 can measure the output current of the power output to the inverter connection unit 103. Even if the output current sensing unit is connected only to the (+) power line 126 of the inverter connection unit in the battery connection unit 102 and the inverter connection unit 103 connected in parallel, the output current to the inverter and the output current to the battery can be calculated using the input current measured by the input current sensing unit 112 and the output current measured by the output current sensing unit 115. The control unit 104 can calculate and monitor the amount of power output to the inverter 230 and the amount of power output to the battery 220. The output current sensing unit 115 can be configured with a current sensor such as Figure 3 shown.

[0062] The first switch unit 116 can connect to or disconnect from the battery 220. The switch element that can connect or disconnect the battery 220 can be connected to the battery connection unit 102. The first switch unit 116 is a relay element, or can include a DC relay, a power semiconductor element, etc. The first switch unit 116 can be connected to the (+) power line 124 of the battery connection unit.

[0063] When the first switching unit 116 connects the battery 220 , a precharger may be included to prevent inrush current, etc. Before connecting the battery 220 , the voltage of the battery connecting unit 102 is formed to correspond to the voltage of the battery 220 by precharging, and then the battery 220 is connected, thereby increasing stability.

[0064] Furthermore, a communication unit may be included to communicate with a battery management system (BMS) that manages the battery 220. The communication unit receives status information such as the charge / discharge amount of the battery 220 from the BMS, and the control unit 104 may use the battery status information to control the first switch unit 116 or the initial charging unit. In this case, the communication unit may communicate with the BMS via wired or wireless communication (such as CAN communication or RS-485).

[0065] The second switch unit 117 can connect or disconnect the inverter 230. A switching element that can connect the inverter 230 or disconnect the PV module 210 and the battery 220 from the inverter 230 can be connected to the inverter connection unit 103. When a fault occurs in the power transmission device according to an embodiment of the present disclosure, if the PV module 210 does not generate power due to the operation of the RSD function, or if a problem occurs in the battery, the second switch unit 117 can operate to disconnect the PV module 210 and the battery 220 from the inverter 230. The second switch unit 117 can be a relay element, or can include a DC relay, a power semiconductor element, etc. The second switch unit 117 can be connected to the (-) power line 127 of the inverter connection unit.

[0066] The bypass unit 118 can form a bypass path on the inverter connection unit 103 when the connection with the inverter connection unit 103 is released according to the operation of the second switch unit. When the second switch unit 117 operates to separate the PV module 210 and the battery 220 from the inverter 230, a bypass path can be formed so that the power supply to the inverter 230 through other elements can be maintained. The bypass unit 118 can be configured as follows Figure 3 Bypass diode connected as shown.

[0067] The power output to the inverter connection unit 103 may be directly applied to the inverter 230, or may be applied to the inverter 230 through the DC-DC converter 240, as shown in FIG. Figure 5 As shown. When the voltage magnitude of the power output to the inverter connection unit 103 corresponds to the voltage of the inverter 230, it may not pass through the DC-DC converter 240. The voltage output to the inverter connection unit 103 can be formed by voltage control according to the charging and discharging of the battery 220. Thus, the DC-DC converter can be eliminated. However, in the absence of series-connected batteries, the DC-DC converter 240 may be required to form the voltage required by the inverter. In addition, in the case of battery separation due to a battery module failure, the battery voltage cannot be used, so the PV module may need to be converted to a voltage suitable for the inverter module, and in the case where the charging power between the battery modules is different, the DC-DC converter 240 may be required to use the battery to the maximum extent.

[0068] The power transmission device according to an embodiment of the present invention includes: a PV module connection unit, the PV module connection unit being connected to the output of the PV module; a power line communication unit, the power line communication unit being connected to the (+) power line of the PV module connection unit and communicating with the PV module; an abnormality detection unit, the abnormality detection unit being connected to the (-) power line of the PV module connection unit and detecting abnormalities of the PV module; an input current sensing unit, the input current sensing unit measuring the current of the (+) power line of the PV module connection unit; a first diode, the first diode being connected to the (+) power line of the PV module connection unit and blocking the current flowing to the PV module; and a battery connection unit, the battery connection unit being connected to the battery. and outputs power to or receives power from a battery; an inverter connection unit, the inverter connection unit being connected in parallel with the battery connection unit and outputting power to the inverter when connected to the inverter; an output current sensing unit, the output current sensing unit measuring an output voltage at a front end of a node to which the battery connection unit and the inverter connection unit are connected; a first switch unit, the first switch unit being connected to a (+) power line of the battery connection unit and connecting or disconnecting the battery; an output current sensing unit, the output current sensing unit measuring a current of the (+) power line of the inverter connection unit; and a second switch unit, the second switch unit being connected to a (-) power line of the inverter connection unit and detecting an abnormality of a PV module. The present invention may include a bypass unit for connecting or disconnecting the second switch unit of the inverter and connected to the (+) power line and the (-) power line of the inverter connection unit to form a bypass path. Furthermore, the present invention may include: an RSD unit connected between the (+) power line and the (-) power line of the PV module connection unit to reduce the voltage of the PV module to below a first value when an abnormality in the PV module is detected; and a first capacitor connected between the (+) power line and the (-) power line at the front end of the node to which the battery connection unit and the inverter connection unit are connected. Detailed description of each configuration corresponds to Figures 1 to 6A detailed description of each component is given below, and therefore, repeated description will be omitted.

[0069] The power transmission device 100 according to an embodiment of the present invention can be connected to other power transmission devices 200, 300, and 400 to supply power to the inverter 230. In this case, the inverter connection unit 103 can be connected in series with the inverter connection units of the other power transmission devices 200, 300, and 400. Thus, the voltages output by each of the PV modules 210, 310, 410, and 510 and the batteries 220, 320, 420, and 520 can be connected in series to form the desired voltage, eliminating the need for the DC-DC converter 240. By supplying power to the inverter 230 without passing through the DC-DC converter 240, energy efficiency can be improved. Furthermore, when multiple power transmission devices are used, if a particular battery or the like fails, a bypass unit 118 is included that can bypass the battery, allowing power to be supplied to the inverter 230 using another battery or the like. Through this configuration and connection relationship, the efficiency of power transmission from PV module 210 to battery 220, power transmission from PV module 210 to the grid through inverter 230, and power transmission from battery 220 to the grid through inverter 230 can be improved.

[0070] In addition, since the battery forms the voltage, inverter link voltage control is not required, and since the batteries are stacked in series, the DC-DC converter can be omitted. In the event of a battery failure, the batteries can be separated and operated. Even if the system is not operating for a long time due to reasons such as user vacation or system failure, the battery can be prevented from being over-discharged by charging the battery with power from the PV module 210. In addition, the control between the batteries can be balanced by controlling the power generation of the PV connected to the battery, and separate charging control can be performed. In addition, it is possible to operate as an AC-coupled product by configuring only the battery 220 (without the PV module 210), the PV module 210 can be added when operating as an AC-coupled product, the battery 220 can be added when operating as a PV inverter product (without the battery 220), and bypass operation can also be performed in the event of a problem in the system configured by each battery module.

[0071] In addition, when providing stable high voltage for buildings or industrial purposes, such as Figure 8 As shown, the scalability of the series-parallel design can be enhanced by connecting multiple battery module units in series in parallel with other battery module units.

[0072] Furthermore, the power transmission device according to an embodiment of the present invention may include: a PV module connection unit that receives power from a PV module; a battery connection unit that is connected to a battery and configured to output power to the battery or receive power from the battery; and an inverter connection unit that outputs power to an inverter and is connected in parallel with the PV module connection unit. Figure 9 As shown, the PV module connection unit and the inverter connection unit are connected in parallel, and the battery connection unit is connected to the battery to supply power to inverter 230 using power from the PV modules or batteries. In this case, DC-DC converter 240 can be eliminated by connecting the batteries in series. In this case, the overall system battery management system 250 can communicate with each of the module battery management systems (M-BMS) 251 to 254, each of the power transmission devices 100, 200, 300, and 400, inverter 230, and DC-DC converter 240 via communication lines. This configuration and connection relationship improves the efficiency of power transmission from PV modules 210, 310, 410, and 510 to batteries 220, 320, 420, and 520, the efficiency of power transmission from PV modules 210, 310, 410, and 510 to the grid via inverter 230, and the efficiency of power transmission from batteries 220, 320, 420, and 520 to the grid via inverter 230.

[0073] Those skilled in the art associated with the present embodiment will appreciate that the above description may be implemented in a modified form without departing from its essential features. Therefore, the disclosed method should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated by the claims rather than the above description, and all differences within their equivalent ranges are to be construed as included in the present invention.

Claims

1. A power transmission device, comprising: a PV module connection unit that receives power input from the PV module; a battery connection unit connected to a battery to output power to the battery or receive power input from the battery; an inverter connection unit that is connected in parallel to the battery connection unit and outputs power to the inverter when connected to the inverter; as well as A control unit is configured to control the PV module by communicating with the PV module, and control the battery connection unit and the inverter connection unit to output power input from the PV module to the battery or the inverter.

2. The power transmission device according to claim 1, comprising: A power line communication unit is configured to perform communication with the PV module through a power line electrically connected to the PV module.

3. The power transmission device according to claim 1, wherein: The PV module comprises a plurality of PV modules, and The plurality of PV modules are connected in parallel to the PV module connection unit.

4. The power transmission device according to claim 1, comprising: An abnormality detection unit is configured to detect whether an abnormality exists in the PV module.

5. The power transmission device according to claim 1, comprising: An RSD unit is configured to reduce a voltage of the PV module below a first value upon detecting an abnormality in the PV module.

6. The power transmission device according to claim 1, comprising: an input current sensing unit configured to measure an input current of power input to the PV module connection unit; an output voltage sensing unit configured to measure an output voltage of power output to at least one of the battery connection unit and the inverter connection unit; as well as An output current sensing unit is configured to measure an output current of power output to the inverter connection unit.

7. The power transmission device according to claim 1, comprising: a first switch unit, configured to connect or disconnect the battery; as well as An initial charging unit is configured to perform initial charging when connected to the battery.

8. The power transmission device according to claim 1, comprising: A communication unit configured to communicate with a battery management device that manages the battery.

9. The power transmission device according to claim 1, comprising: a second switch unit, configured to connect or disconnect the inverter; as well as A bypass unit forms a bypass path on the inverter connection unit when disconnecting from the inverter connection unit according to an operation of the second switching unit.

10. The power transmission device according to claim 1, wherein: The inverter connection unit is connected in series with an inverter connection unit of another power transmission device.

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