Effect improving device of photovoltaic inverter

Abstract

The utility model discloses an efficiency improving device of a photovoltaic inverter, which comprises a base, a first power generation device, a second power generation device, a first inverter, a second inverter and a full-load control device, the first inverter and the second power generation device are independently connected through a full-load control device, the second inverter and the first power generation device are independently connected through a full-load control device, and each full-load control device comprises a PLC execution terminal, a current detection device and a conduction switch. When the weather is sunny and the illumination is sufficient, the first inverter and the second inverter are both in a full-load state, and the generating capacity is reduced in cloudy and rainy weather, so that the first inverter and the second inverter are in a light-load state, and at the moment, the PLC execution terminal instructs the conduction switch to be switched on, so that the first inverter and the second inverter are restored to the full-load state again. And when the weather is clear, the conduction switch is instructed to be switched off, so that the first inverter and the second inverter are in a full-load state for a long time, and the overall current conversion efficiency is further improved.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic inverter technology, and in particular to an efficiency-enhancing device for photovoltaic inverters. Background Technology

[0002] Photovoltaic inverters use power electronic conversion technology to convert the DC power of a photovoltaic array into AC power that can be connected to the grid or supplied to loads. They also have functions such as maximum power point tracking (MPPT), islanding protection, and grid support. They are the "bridge" connecting solar power generation and the power grid, and directly affect the system's power generation efficiency and stability.

[0003] In a photovoltaic power generation system, the conversion efficiency of the inverter directly affects the power generation of the system. Under sunny weather conditions with sufficient sunlight, the photovoltaic panels can generate more electricity. At this time, the inverter is at full load and has a high conversion efficiency. However, under cloudy or rainy weather conditions, the sunlight intensity is weakened, the power generation of the photovoltaic panels is reduced, and the inverter is at a light load. The conversion efficiency is reduced, resulting in some performance waste of the inverter and a decrease in power generation. Utility Model Content

[0004] The purpose of this invention is to provide an efficiency-enhancing device for photovoltaic inverters to solve the above-mentioned problems.

[0005] The technical solution of this utility model is implemented as follows:

[0006] This utility model provides an efficiency improvement device for a photovoltaic inverter, including a base and a first power generation device, a second power generation device, a first inverter, and a second inverter mounted on the base. The first power generation device and the first inverter are independently matched and connected, and the second power generation device and the second inverter are independently matched and connected. It also includes a full-load control device, through which the first inverter and the second power generation device, and the second inverter and the first power generation device, are independently connected. The full-load control device includes:

[0007] The PLC execution terminal is used to receive and process information, and outputs instructions when the collected values ​​reach a specified threshold.

[0008] A current detection device is used to detect the magnitude of the current output by the first inverter and the second inverter. It includes a current transformer and an electricity meter. One end of the electricity meter is electrically connected to the AC side of the first inverter and the AC side of the second inverter, and the other end is electrically connected to the current transformer. The current transformer is electrically connected to the PLC execution terminal.

[0009] A switching circuit is used to connect the circuit of the first inverter to the circuit of the second power generation device and the circuit of the second inverter to the circuit of the first power generation device, and the switching circuit is electrically connected to the PLC execution terminal.

[0010] In one embodiment, a heat-conducting copper pipe is fixedly mounted on the outer side of both the first inverter and the second inverter. A first guide plate and two second guide plates are provided on the outer side of the heat-conducting copper pipe. The first guide plate is placed parallel to the outer surface of the heat-conducting copper pipe and fixed in the middle of the heat-conducting copper pipe. The two second guide plates are respectively fixed on both sides of the first guide plate, and the end of the second guide plate away from the first guide plate is inclined and expanded outward. A cooling fan is also fixedly mounted on the outer side of the first inverter and the second inverter. The air outlet of the cooling fan is directed towards the inclined end of one of the second guide plates.

[0011] In one embodiment, the first inverter and the second inverter are further provided with disc-shaped copper tubes and equipped with a refrigeration unit connected to them. The refrigeration unit is fixed on the base, the disc-shaped copper tubes are located in the gaps of the heat-conducting copper tubes, and coolant is injected into the disc-shaped copper tubes. The motor of the refrigeration unit is electrically connected to the PLC control terminal.

[0012] In one embodiment, the cooling fan is externally connected to a PWM control board, which is connected to a PLC execution terminal. Both the first inverter and the second inverter are equipped with temperature sensors, which are electrically connected to the PLC execution terminal.

[0013] In one embodiment, a liquid storage tank is also fixed on the base, and the liquid storage tank forms a circuit with the refrigeration unit.

[0014] In one embodiment, the first guide plate and the second guide plate have multiple interconnected air ducts inside, and the second guide plate has a number of air guide holes connected to the air ducts on the side facing the heat dissipation copper pipe.

[0015] The advantages or beneficial effects of the above technical solutions include at least the following:

[0016] Under sunny and bright conditions, the first and second power generation devices generate sufficient power. At this time, the first inverter and the first power generation device are connected independently, and the second inverter and the second power generation device are connected independently. Both the first and second inverters are at full load, resulting in high conversion efficiency. Under cloudy or rainy weather with reduced sunlight, the power generation of the first and second power generation devices decreases, causing the first and second inverters to be in a light load state, resulting in reduced conversion efficiency. When the current detection device feeds this result back to the PLC execution terminal, it will instruct the conduction switch to open, so that the first inverter, the first power generation device, and the second power generation device are connected in parallel, and the second inverter, the first power generation device, and the second power generation device are connected in parallel. This increases the DC output current of the first and second inverters, allowing them to return to full load. When the weather clears up, the PLC execution terminal controls the conduction switch to open. Through this free switching of working states, the first and second inverters are in a full load state for a long time, thereby improving the overall current conversion efficiency. Attached Figure Description

[0017] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0018] Figure 1 This is an external three-dimensional schematic diagram of the overall structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the operating logic of the full-load control device in this utility model.

[0020] Figure 3 This is a schematic diagram of the external structure of the heat-conducting copper tube in this utility model.

[0021] Figure 4 This is a schematic diagram of the external structure of the heat-conducting copper tube combined with the disc-shaped copper tube in this utility model.

[0022] Figure 5 This is a cross-sectional view of the combination of the first guide plate and the second guide plate in this utility model.

[0023] Reference numerals in the attached drawings: 1. Base; 2. First power generation device; 3. Second power generation device; 4. First inverter; 5. Second inverter; 6. Full load control device; 7. Heat-conducting copper pipe; 8. First guide plate; 9. Second guide plate; 10. Cooling fan; 11. Disc-shaped copper pipe; 12. Refrigeration unit; 13. PWM control board; 14. Temperature sensor; 15. Liquid storage tank; 16. Air vent. Detailed Implementation

[0024] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0025] It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] It should be understood that the term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this utility model are only used to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0027] It should be noted that the terms "a" and "a plurality of" used in this utility model are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0028] The names of the messages or information exchanged between the multiple devices in this embodiment of the invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0029] Reference Figure 1 An efficiency-enhancing device for a photovoltaic inverter includes a base 1 and a first power generation device 2, a second power generation device 3, a first inverter 4, and a second inverter 5 installed on the base 1. The first power generation device 2 and the first inverter 4 are independently matched and connected, and the second power generation device 3 and the second inverter 5 are independently matched and connected. When the weather is sunny and there is sufficient sunlight, the photovoltaic panels in the first power generation device 2 and the second power generation device 3 can generate more electrical energy. At this time, the first inverter 4 and the second inverter 5 are running at full load and have high conversion efficiency.

[0030] Reference Figure 1 and Figure 2It also includes a full-load control device 6. The first inverter 4 and the second power generation equipment 3, as well as the second inverter 5 and the first power generation equipment 2, are independently connected through the full-load control device 6. The full-load control device 6 includes:

[0031] The PLC execution terminal is used to receive and process information, and outputs instructions when the collected values ​​reach a specified threshold.

[0032] The current detection device is used to detect the magnitude of the output current of the first inverter 4 and the second inverter 5. It includes a current transformer and an electricity meter. One end of the electricity meter is electrically connected to the AC side of the first inverter 4 and the AC side of the second inverter 5, respectively, and the other end is electrically connected to the current transformer. The current transformer is electrically connected to the PLC execution terminal.

[0033] The on / off switch is used to connect the circuit of the first inverter 4 with the circuit of the second power generation device 3 and the circuit of the second inverter 5 with the circuit of the first power generation device 2, and the on / off switch is electrically connected to the PLC execution terminal.

[0034] With this setup, when the sunlight intensity weakens during cloudy or rainy weather, the reduced power generation from the photovoltaic panels leads to a decrease in the current input to the first inverter 4 and the second inverter 5, placing them in a light-load state. The electricity meter detects that the AC output current of the first inverter 4 and the second inverter 5 has dropped to a value outside the fluctuation range and transmits the detected value to the current transformer. The current transformer calculates the real-time conversion efficiency of the first inverter 4 and the second inverter 5 by measuring the current and voltage, and feeds the result back to the PLC execution terminal. Once the PLC execution terminal recognizes the decrease in the conversion efficiency of the first inverter 4 and the second inverter 5, it instructs the switching switch to connect, thus connecting the circuits of the first inverter 4 and the second generator 3, and the second inverter 5 and the first generator 2. At this point, the first inverter 4, the first generator 2, and the second generator 3 are connected in parallel. Furthermore, the second inverter 5, the first generator 2, and the second generator 3 are also connected in parallel, causing the current input to the first inverter 4 and the second inverter 5 to rise again, and the first inverter 4 and the second inverter 5 to return to full load, thus increasing the conversion efficiency. When the weather turns sunny again, the current input to the first inverter 4 and the second inverter 5 increases significantly. At this time, the current transformer detects that the voltage is too high and feeds the situation back to the PLC execution terminal. After the PLC execution terminal recognizes the situation, it instructs the on / off switch to open, so that the first inverter 4 is reconnected independently to the first generator 2, and the second inverter 5 is reconnected independently to the second generator 3. At this time, the first inverter 4 and the second inverter 5 are still in full load. Through the above switching of working states, the inverters can be kept in full load for a long time to ensure high conversion efficiency.

[0035] Reference Figure 1 , Figure 3 and Figure 5 Both the first inverter 4 and the second inverter 5 are equipped with heat-conducting copper pipes 7 on their outer sides. Each heat-conducting copper pipe 7 has a first guide plate 8 and two second guide plates 9 on its outer side. The first guide plate 8 is placed parallel to the outer surface of the heat-conducting copper pipe 7 and fixed in the middle of the pipe. The two second guide plates 9 are respectively fixed on both sides of the first guide plate 8, with the end of each second guide plate 9 away from the first guide plate 8 inclined outwards. A cooling fan 10 is also fixed to the outer side of both the first inverter 4 and the second inverter 5. The air outlet of the cooling fan 10 faces the inclined end of one of the second guide plates 9. With this configuration, the heat-conducting copper pipes 7 can dissipate the heat generated by the first inverter 4 and the second inverter 5. Heat is dissipated to the outside through heat transfer, and the first guide plate 8 and the second guide plate 9 guide the airflow. When the natural wind blows towards the inclined end of the second guide plate 9, the space between the second guide plate 9 and the heat-conducting copper pipe 7 continuously decreases, resulting in a continuous decrease in the flow space of the natural wind. Due to the narrow tube effect, the wind speed flowing towards the first guide plate 8 will continuously increase, thereby accelerating the loss of heat. At the same time, the hot air can continuously rise and flow outward under the guidance of the inclined surface of the second guide plate 9, further accelerating the speed at which the heat-conducting copper pipe 7 dissipates heat. When the airflow of the natural wind is not large, the cooling fan 10 will replace it to increase the airflow and ensure the heat dissipation effect of the heat-conducting copper pipe 7.

[0036] In one specific embodiment, both the first guide plate 8 and the second guide plate 9 are made of copper, which makes the first guide plate 8 and the second guide plate 9 themselves have heat conduction function, increasing the overall heat conduction area and thus further enhancing the heat dissipation effect.

[0037] Reference Figure 1 and Figure 4 The first inverter 4 and the second inverter 5 are also equipped with a disc-shaped copper tube 11 and a refrigeration unit 12 connected to it. The refrigeration unit 12 is fixed on the base 1. The disc-shaped copper tube 11 is located in the gap of the heat-conducting copper tube 7 and is filled with coolant. The motor of the refrigeration unit 12 is electrically connected to the PLC control terminal. With this setting, when the heat-conducting copper tube 7 cannot dissipate heat in time, the PLC control terminal controls the refrigeration unit 12 to start, so that the coolant in the disc-shaped copper tube 11 begins to circulate, so as to carry away the heat of the heat-conducting copper tube 7, improve the cooling effect, and prevent the first inverter 4 and the second inverter 5 from being unable to stabilize at full load due to the ambient temperature being high for a long time.

[0038] Reference Figure 1The cooling fan 10 is externally connected to a PWM control board 13, which is connected to a PLC execution terminal. Both the first inverter 4 and the second inverter 5 are equipped with temperature sensors 14, which are electrically connected to the PLC execution terminal. With this setup, the temperature sensors 14 detect the temperature of the first inverter 4 and the second inverter 5 in real time and feed the results back to the PLC execution terminal. The PLC execution terminal then controls the speed of the cooling fan 10 through the PWM control board 13, so that the speed of the cooling fan 10 increases as the temperature of the first inverter 4 and the second inverter 5 rises, until it reaches full speed. This prevents the cooling fan 10 from running at full speed at low temperatures, which would not only waste performance and power, but also increase noise.

[0039] In one specific embodiment, when the cooling fan 10 is running at full speed but the temperatures of the first inverter 4 and the second inverter 5 are still rising, the temperature sensor 14 feeds this result back to the PLC execution terminal, which then instructs the chiller unit 12 to start working. The coolant in the disc copper pipe 11 begins to circulate, carrying away the heat from the cooling copper pipe. When the temperature sensor 14 detects that the temperatures of the first inverter 4 and the second inverter 5 have dropped, the PWM control board 13 synchronously controls the cooling fan 10 to reduce its speed until the cooling fan 10 stops running. At this time, the disc copper pipe 11 completely takes over the heat dissipation work. During this interval, the cooling fan 10 is in a resting state to prevent the cooling fan 10 from running for a long time and excessively damaging its mechanical life. When the first inverter 4 and the second inverter 5 drop to a low temperature, the PLC execution terminal instructs the cooling fan 10 to work again, and the chiller unit 12 stops running. At this time, the cooling fan 10 takes over the heat dissipation work.

[0040] Reference Figure 1 A liquid storage tank 15 is also fixed on the base 1. The liquid storage tank 15 forms a loop with the refrigeration unit 12. With this configuration, not only can the coolant be stored in the liquid storage tank 15 when the refrigeration unit 12 is not working, thus avoiding the coolant from being dried by the heat of the heat dissipation copper pipe due to not circulating in the disc copper pipe for a long time, but the circulation stroke of the coolant is also increased. The coolant circulating to the liquid storage tank 15 can be naturally cooled, further improving the cooling effect of the coolant.

[0041] Reference Figure 1 and Figure 5 The first guide plate 8 and the second guide plate 9 have multiple interconnected air ducts inside, and the second guide plate 9 has several air guide holes 16 connected to the air ducts on the side facing the heat dissipation copper pipe. This arrangement increases the ventilation area of ​​the first guide plate 8 and the second guide plate 9, allowing natural wind or airflow provided by the cooling fan 10 to enter through the air guide holes 16 and circulate in the air ducts, so as to further remove the heat from the heat dissipation copper pipe and improve its heat dissipation effect.

[0042] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0043] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. An efficiency-enhancing device for a photovoltaic inverter, comprising a base (1) and a first power generation device (2), a second power generation device (3), a first inverter (4), and a second inverter (5) mounted on the base (1), wherein the first power generation device (2) is independently matched and connected to the first inverter (4), and the second power generation device (3) is independently matched and connected to the second inverter (5), characterized in that: It also includes a full-load control device (6), through which the first inverter (4) and the second power generation equipment (3) are independently connected, and the second inverter (5) and the first power generation equipment (2) are independently connected. The full-load control device (6) includes: The PLC execution terminal is used to receive and process information, and outputs instructions when the collected values ​​reach a specified threshold. A current detection device is used to detect the magnitude of the current output by the first inverter (4) and the second inverter (5). It includes a current transformer and an electricity meter. One end of the electricity meter is electrically connected to the AC side of the first inverter (4) and the AC side of the second inverter (5), respectively, and the other end is electrically connected to the current transformer. The current transformer is electrically connected to the PLC execution terminal. A switching circuit is used to connect the circuit of the first inverter (4) to the circuit of the second power generation device (3) and the circuit of the second inverter (5) to the circuit of the first power generation device (2), and the switching circuit is electrically connected to the PLC execution terminal.

2. The efficiency improvement device for a photovoltaic inverter according to claim 1, characterized in that: A heat-conducting copper pipe (7) is fixedly provided on the outside of the first inverter (4) and the second inverter (5). A first guide plate (8) and two second guide plates (9) are provided on the outside of the heat-conducting copper pipe (7). The first guide plate (8) is placed parallel to the outer surface of the heat-conducting copper pipe (7) and fixed in the middle of the heat-conducting copper pipe (7). The two second guide plates (9) are respectively fixed on both sides of the first guide plate (8), and the end of the second guide plate (9) away from the first guide plate (8) is inclined and expanded outward. A cooling fan (10) is also fixedly provided on the outside of the first inverter (4) and the second inverter (5). The air outlet of the cooling fan (10) is inclined towards the end of one of the second guide plates (9).

3. The efficiency improvement device for a photovoltaic inverter according to claim 1, characterized in that: The first inverter (4) and the second inverter (5) are also provided with a disc copper tube (11) and a refrigeration unit (12) connected to it. The refrigeration unit (12) is fixed on the base (1). The disc copper tube (11) is located in the gap of the heat-conducting copper tube (7) and coolant is injected into the disc copper tube (11). The motor of the refrigeration unit (12) is electrically connected to the PLC control terminal.

4. The efficiency improvement device for a photovoltaic inverter according to claim 2, characterized in that: The cooling fan (10) is externally connected to a PWM control board (13), which is connected to a PLC execution terminal. Both the first inverter (4) and the second inverter (5) are equipped with temperature sensors (14), which are electrically connected to the PLC execution terminal.

5. The efficiency improvement device for a photovoltaic inverter according to claim 3, characterized in that: A liquid storage tank (15) is also fixed on the base (1), and a circuit is formed between the liquid storage tank (15) and the refrigeration unit (12).

6. The efficiency improvement device for a photovoltaic inverter according to claim 2, characterized in that: The first guide plate (8) and the second guide plate (9) have multiple interconnected air ducts inside, and the second guide plate (9) has several air ducts (16) connected to the air ducts on the side facing the heat dissipation copper pipe.

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