CN202444430U - Photovoltaic grid-connected inverter and power module for same - Google Patents

Abstract

The utility model relates to a power module of a modular photovoltaic grid-connected inverter, which includes a power device, an electrolytic capacitor, a radiator and a drive circuit board, the electrolytic capacitor is connected to the power device through the circuit board, and the radiator is connected to the power device. The power device is in contact, wherein the heat sink is provided with an air inlet and a main air outlet, and the inside of the heat sink forms a main air channel for allowing external air to flow through it, and the main air channel is provided with The secondary air outlet is provided with an air deflector for guiding part of the air flowing in the main air duct to the electrolytic capacitor. The photovoltaic grid-connected inverter according to the utility model has the following advantages: the novel bus capacitor forced air cooling design realizes the forced air cooling of the bus capacitor at low cost without increasing the cost, improving the reliability of the system Sex; using the redundant heat dissipation capacity of the main fan, part of the cold air is led out in advance to dissipate heat from the bus capacitor.

Description

Power modules for photovoltaic grid-connected inverters and photovoltaic grid-connected inverters

technical field

The utility model relates to the technical field of inverters, in particular to a photovoltaic grid-connected inverter with the function of cooling electrolytic capacitors and a power module thereof.

Background technique

The photovoltaic grid-connected power generation system is a photovoltaic power generation system that is connected to the grid and transmits power to the grid. The photovoltaic grid-connected inverter is an important part of the photovoltaic grid-connected power generation system. It is used to convert the direct current from the solar panel into alternating current, so as to output a sinusoidal alternating current with the same frequency and phase as the grid voltage to the grid.

At present, electrolytic capacitors are usually used as input inverter bus filter capacitors (referred to as bus capacitors) of photovoltaic grid-connected inverters for filtering DC and storing energy. The performance and life of the electrolytic capacitor are related to the performance of the photovoltaic grid-connected inverter and the entire photovoltaic module, and also determine the stability of the photovoltaic power generation system. The life of the electrolytic capacitor depends on its working temperature. If the electrolytic capacitor is not dissipated during its operation, the excessive heat will accelerate the evaporation of the electrolyte. When the amount of electrolyte is reduced to a certain limit, the life of the capacitor will end. . As shown in Figure 1, the photovoltaic grid-connected inverters currently on the market only dissipate heat from power devices (eg, IGBT), while the heat dissipation of electrolytic capacitors only depends on the direct contact between the electrolytic capacitor itself and the ambient air, resulting in the heat dissipation of the electrolytic capacitor not effectively.

To solve the above problems, referring to FIG. 2 , a special cooling device (for example, fan 304 ) can be designed to dissipate heat from the electrolytic capacitor so as to cool it down, but this will increase the cost of the entire system.

Utility model content

The technical problem to be solved by the utility model

The inventors of the present application have completed the present invention in consideration of the above-mentioned circumstances of the prior art. The main purpose of the utility model is to ensure the heat dissipation of the electrolytic capacitor in the photovoltaic grid-connected inverter, and prolong the service life of the electrolytic capacitor and even the photovoltaic grid-connected inverter.

means of solving technical problems

According to one aspect of the present invention, a power module for a photovoltaic grid-connected inverter is provided, including a power device, an electrolytic capacitor, a heat sink, and a driving circuit board, and the electrolytic capacitor communicates with the driving circuit board through the The power device is connected, the heat sink is in contact with the power device, wherein the heat sink is provided with an air inlet and a main air outlet, and the inside of the heat sink forms a main air flow for external air to flow therethrough. A secondary air outlet is provided on the main air channel for guiding part of the air flowing in the main air channel to the electrolytic capacitor.

In a preferred embodiment, the photovoltaic grid-connected inverter of the present utility model is provided with an air deflector at the secondary air outlet, which is used to guide part of the air flowing in the main air channel to the secondary air outlet through the secondary air outlet. The above electrolytic capacitor.

In a preferred embodiment, the shape of the secondary air outlet is, for example, a narrow slit, such as a long and thin rectangular shape, with a length of, for example, 45 cm and a width of, for example, 2 mm, which is arranged on the air duct plate of the main air duct Any position where air can be supplied to the electrolytic capacitor is preferably set at a position on the air duct plate that is not on the same vertical line as the electrolytic capacitor and is as close as possible to the electrolytic capacitor, for example, the closest distance to the electrolytic capacitor is 5 cm. The air deflector is, for example, arranged along the two long sides of the secondary air outlet, and may be one or two, usually two air deflectors arranged along the two long sides. For example, in the case of two, the wind deflector farther away from the electrolytic capacitor can be set upward, the one wind deflector closer to the electrolytic capacitor can be set downward, or both wind deflectors can be set upward at the same time, so that Direct cold air to a location close to the electrolytic capacitors. The wind deflector is usually inclined relative to the horizontal plane, and the angle of inclination can be any angle suitable for supplying air to the electrolytic capacitor. For example, the included angle between the wind deflector and the horizontal plane is 15 to 60 degrees, preferably, for example, 25 to 45 degrees. Spend.

In a preferred embodiment, the cross-sectional shape of the air deflector is, for example, an arc shape or a flat plate shape or any other shape suitable for supplying air to the electrolytic capacitor. The size of the wind deflector is not particularly limited. For example, the length of the wind deflector can be the same as the length of the secondary air outlet (for example, 45 cm), and the width of the wind deflector is, for example, 5 mm to 4 cm, further such as 1 cm to 4 cm. 2 cm, the thickness can be, for example, 0.5 mm to 5 mm, and further, for example, 1 mm to 2 mm.

In another preferred embodiment of the power module of the photovoltaic grid-connected inverter of the present invention, a thermostat is also installed on the electrolytic capacitor, and the thermostat monitors the operating temperature of the electrolytic capacitor and The inclination angle of the air deflector is controlled according to the monitored temperature, thereby controlling the air volume passing through the secondary air outlet.

According to an aspect of the present invention, a photovoltaic grid-connected inverter including the above-mentioned power module is also provided.

Advantages of the utility model

According to the utility model, the photovoltaic grid-connected inverter and its power module have the following advantages: the novel bus capacitor forced air cooling design realizes the forced air cooling of the bus capacitor at low cost without increasing the cost, improving The reliability of the system is improved; by using the redundant heat dissipation capacity of the main fan, part of the cold air is led out in advance to dissipate the heat of the bus capacitor.

Description of drawings

1 is a schematic diagram showing a prior art power module for a photovoltaic grid-connected inverter, wherein 20 is a power module, 201 is a power device, 202 is an electrolytic capacitor, and 203 is a radiator;

Fig. 2 is a schematic diagram showing another prior art power module for a photovoltaic grid-connected inverter, wherein 30 is a power module, 301 is a power device, 302 is an electrolytic capacitor, 303 is a radiator, and 304 is a fan ;

3 is a schematic diagram showing a power module for a photovoltaic grid-connected inverter according to an embodiment of the present invention, wherein 10 is a power module, 101 is a power device, 102 is an electrolytic capacitor, 103 is a radiator, and 104 is Air deflector, 105 is a driving circuit board, and 106 is a secondary air outlet.

Detailed ways

The utility model will be further understood through the following description of the embodiments with reference to the above-mentioned drawings.

Fig. 3 is a schematic diagram of a power module 10 for a photovoltaic grid-connected inverter according to an embodiment of the present invention. As shown in Figure 3, the photovoltaic grid-connected inverter is, for example, a modular photovoltaic grid-connected inverter, which includes a power module 10, and the power module 10 includes a power device 101, an electrolytic capacitor 102 (also called a bus capacitor), The radiator 103 , the wind deflector 104 and the driving circuit board 105 .

The power device 101 can be an IGBT, the electrolytic capacitor 102 is connected to the power device 101 through a copper bar, and the heat sink 103 is in contact with the power device 101 , and the contact surface can be coated with thermal conductive silicone grease, for example. Two ends of the heat sink 103 are provided with a main air outlet and an air inlet, and a main air duct is formed inside the radiator 103, which is used for passing ambient air through a fan, thereby producing the effect of air cooling. The heat sink 103 can be made of metal, such as pure copper, aluminum profile with oxidized surface, etc., which can be formed into heat dissipation fins, heat dissipation grooves, and the like. The secondary air outlet 106 is designed on the air duct plate of the main air duct of the radiator 103, and it passes through the wind deflector 104 (shown in Fig. 3 along the two long sides of the secondary air outlet of the slit shape) The two air deflectors provided, one of which is arc-shaped and the other is flat-plate) guide part of the air volume flowing in the main air duct to the electrolytic capacitor 102 outside the radiator 103 . The control circuit and power devices are connected through the driving circuit board 105 .

The wind deflector 104 may be fixed. At the same time, optionally, the wind deflector 104 can also be adjustable, and the opening of the air outlet can be adjusted by adjusting the posture (such as inclination, length, etc.) of the wind deflector 104, thereby adjusting the air volume of the air outlet, And then the cooling strength of the electrolytic capacitor.

Optionally, a thermostat (not shown) is also installed on the electrolytic capacitor 102, and the thermostat monitors the operating temperature of the electrolytic capacitor 102, and controls the electrolytic capacitor 102 according to the monitored temperature. The inclination angle, length, etc. of the wind deflector 104 are controlled to control the air volume passing through the secondary air outlet 106 .

Using the remaining cooling capacity of the strong wind pressure centrifugal fan of the power module, before the main airflow enters the radiator 103 through the fan, it passes through the thinner air outlet on the main air duct plate, and uses the air deflector 104 to generate an air volume outside the main air duct A suitable cooling branch directs a part of the main airflow to the electrolytic capacitor 102 , thereby realizing forced air cooling of the electrolytic capacitor 102 . By forced air cooling, the temperature rise of the electrolytic capacitor 102 can be effectively reduced, thereby prolonging the life of the electrolytic capacitor 102 , and even the life of the entire power module 10 and the photovoltaic grid-connected inverter.

The beneficial effects produced by the embodiments of the present invention are described below. For example, according to the photovoltaic inverter of the above-mentioned embodiment, the applicant used a 500KW photovoltaic inverter to conduct a temperature rise test. After the inverter works continuously for 4 hours, the operating temperature of the electrolytic capacitor is 52 degrees Celsius without the use of the air guide, and the operating temperature of the electrolytic capacitor after 4 hours of operation is 43 degrees Celsius with the use of the air guide. . Therefore, the operating temperature of the electrolytic capacitor can be reduced by about 9 degrees Celsius when the air guide is added.

It should be noted that, except for the air-cooling of the electrolytic capacitors, other components and structures of the photovoltaic grid-connected inverter of the present invention can be those commonly used in the field, therefore, for the sake of brevity, they are omitted here its description.

Finally, those skilled in the art can understand that various modifications, variations, and replacements can be made to the above-mentioned embodiments of the present invention, all of which fall within the scope of protection of the present invention as defined by the appended claims.

Claims (10)

1. A power module for a photovoltaic grid-connected inverter, the power module includes a power device, an electrolytic capacitor, a radiator and a drive circuit board, and the electrolytic capacitor is connected to the power device through the drive circuit board , the heat sink is in contact with the power device, Wherein, the radiator is provided with an air inlet and a main air outlet, and the interior of the radiator forms a main air duct for allowing external air to flow through it, and a secondary air outlet is provided on the main air duct for Part of the air flowing in the main air duct is guided to the electrolytic capacitor. 2. The power module according to claim 1, wherein an air deflector is provided at the secondary air outlet for guiding part of the air flowing in the main air duct to the electrolytic capacitor through the secondary air outlet . 3. The power module according to claim 1, wherein the cross-sectional shape of the wind deflector is arc-shaped or flat-shaped. 4. The power module according to claim 1, wherein the included angle between the wind guide plate and the horizontal plane is 15-60 degrees. 5. The power module according to claim 1, wherein a temperature controller is also installed on the electrolytic capacitor, and the temperature controller monitors the operating temperature of the electrolytic capacitor and controls the temperature according to the monitored temperature. The inclination angle of the air deflector controls the air volume passing through the secondary air outlet. 6. The power module according to claim 1, wherein the secondary air outlet is shaped like a slit. 7. The power module according to claim 6, wherein the secondary air outlet is rectangular, and is arranged on any position on the air duct plate of the main air duct that can supply air to the electrolytic capacitor. 8. The power module according to claim 7, wherein the secondary air outlet is arranged at a position of the air duct plate not on the same vertical line as the electrolytic capacitor and as close as possible to the electrolytic capacitor. 9. The power module according to claim 8, wherein the air deflector is arranged along two long sides of the secondary air outlet, and the number of the air deflector is one or two. 10. A photovoltaic grid-connected inverter comprising one or more power modules according to any one of claims 1-9.

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