Heat dissipation devices and control methods for photovoltaic inverters

Abstract

The present invention discloses a heat dissipation device and control method for a photovoltaic inverter, wherein the heat dissipation device comprises a heat dissipation chamber housing, a control unit, a fan group, a radiator and a temperature collection unit, the control unit is electrically connected to the fan group, the radiator and the temperature collection unit in a one-to-one correspondence; the radiator and the fan group are located on the heat dissipation chamber housing, the temperature collection unit and the fan group are both arranged at any position close to the radiator, and the radiator is arranged adjacent to the power device of the photovoltaic inverter; wherein at least two fans are arranged in the fan group. The present invention collects the temperature of the radiator through the temperature collection unit, thereby reducing the loss of the fan and prolonging the life of the fan; and by providing multiple fans for air cooling and heat dissipation, when one of the fans fails, because there are other fans that can perform air cooling and heat dissipation, there is no need to directly reduce the output power of the photovoltaic inverter, thereby improving the power generation efficiency and reliability of the photovoltaic inverter.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit protection, and in particular to a heat dissipation device and a control method for a photovoltaic inverter. Background Art

[0002] As the power of string photovoltaic inverters continues to increase, natural heat dissipation is difficult to meet the demand. For photovoltaic inverters with a power greater than 50kW, forced air cooling is recommended.

[0003] The current inverter air cooling system has simple control and high fan power consumption. The fan works in harsh outdoor environments and has a high fan failure rate, causing the inverter to report a fault and shut down, or to operate at reduced power, affecting the power generation efficiency of the photovoltaic power station.

[0004] The typical fan control method is to collect the inverter power and radiator temperature signals through the controller. When the inverter power reaches a certain value (such as 30% load), the fan is turned on; or further, according to the power of the inverter, several different gears of fan speed are set, such as when the load reaches 25%, the 1st windshield is turned on, when the load reaches 40%, the 2nd windshield is turned on, and when the load reaches 60%, the 3rd windshield is turned on. When the radiator temperature collected by the controller reaches the over-temperature value, the output is gradually reduced until the temperature drops to a safe range.

[0005] However, the above control method has the following problems: (1) The inverter is in a relatively low working environment temperature most of the time. For example, in winter, the inverter is in a low temperature environment most of the time, and operates at medium or low power, so there is no need to turn on the fan. The inverter is also in a relatively low ambient temperature (such as below 25°C) in other seasons, and the fan does not need to run at full power. That is, the prior art uses the power of the inverter as a start-up condition, so that the fan is turned on in a low temperature environment, or even at a high speed, which not only consumes a lot of energy, but also shortens the life of the fan. (2) The working environment of the inverter fan is poor and the failure rate is high. When the fan fails, the prior art directly reduces the output power of the inverter, affecting the power generation efficiency of the power station. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a heat dissipation device and a control method for a photovoltaic inverter to improve the power generation efficiency of the photovoltaic inverter.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] The heat dissipation device of the photovoltaic inverter comprises a heat dissipation chamber housing, a control unit, a fan group, a radiator and a temperature collection unit, wherein the control unit is electrically connected to the fan group, the radiator and the temperature collection unit in a one-to-one correspondence;

[0009] The radiator and the fan group are located on the heat dissipation chamber housing, the temperature collection unit and the fan group are both arranged at any position close to the radiator, and the radiator is arranged adjacent to the power device of the photovoltaic inverter;

[0010] At least two fans are arranged in the fan group.

[0011] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0012] The heat dissipation control method of a photovoltaic inverter comprises the following steps:

[0013] S1, receiving the real-time temperature value of the radiator collected by the temperature collection unit;

[0014] S2, judging whether all fans of the fan group are faulty, if all fans of the fan group are not faulty, entering the temperature control mode, otherwise judging whether the number of fans with faults in the fan group is greater than 1, if so, reducing the maximum output power of the photovoltaic inverter and then entering the temperature control mode, otherwise directly entering the temperature control mode, the temperature control mode is to control the operation state of the fan group according to the real-time temperature value of the radiator;

[0015] S3, controlling the fan group to perform air cooling on the radiator and power devices of the photovoltaic inverter.

[0016] The beneficial effects of the present invention are as follows: the heat dissipation device and control method of the photovoltaic inverter collects the temperature of the radiator through a temperature collection unit, which greatly reduces the operation time of the fan, reduces the loss of the fan and prolongs the life of the fan; and by providing multiple fans for air cooling and heat dissipation, when one of the fans fails, there are other fans that can perform air cooling and heat dissipation, so there is no need to directly reduce the output power of the photovoltaic inverter, thereby improving the power generation efficiency and reliability of the photovoltaic inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional schematic diagram of a heat dissipation device for a photovoltaic inverter according to an embodiment of the present invention;

[0018] Figure 2 It is a partially disassembled schematic diagram of a heat dissipation device of a photovoltaic inverter according to an embodiment of the present invention;

[0019] Figure 3 A schematic flow chart of a heat dissipation control method for a photovoltaic inverter according to an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of a heat dissipation control method for a photovoltaic inverter according to an embodiment of the present invention;

[0021] Figure 5 A schematic diagram of a specific process of a heat dissipation control method for a photovoltaic inverter according to an embodiment of the present invention;

[0022] Figure 6 It is a specific flow chart of the temperature control mode involved in the embodiment of the present invention.

[0023] Description of labels:

[0024] 1. Heat dissipation chamber casing; 2. Fan assembly; 3. Radiator; 4. Temperature acquisition unit; 5. Control unit; 11. Heat dissipation holes; 21. Fan; 100. Maximum power device; 101. Boost inductor; 102. Filter inductor. DETAILED DESCRIPTION

[0025] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0026] Please refer to Figure 1 to Figure 2 , a heat dissipation device of a photovoltaic inverter, comprising a heat dissipation chamber housing, a control unit, a fan group, a radiator and a temperature collection unit, wherein the control unit is electrically connected to the fan group, the radiator and the temperature collection unit in a one-to-one correspondence;

[0027] The radiator and the fan group are located on the heat dissipation chamber housing, the temperature collection unit and the fan group are both arranged at any position close to the radiator, and the radiator is arranged adjacent to the power device of the photovoltaic inverter;

[0028] At least two fans are arranged in the fan group.

[0029] From the above description, it can be seen that the beneficial effects of the present invention are: the temperature of the radiator is collected by the temperature collection unit, which greatly reduces the running time of the fan, reduces the loss of the fan and prolongs the life of the fan; and by providing multiple fans for air cooling and heat dissipation, when one of the fans fails, there are other fans that can perform air cooling and heat dissipation, so there is no need to directly reduce the output power of the photovoltaic inverter, thereby improving the power generation efficiency and reliability of the photovoltaic inverter.

[0030] Furthermore, a plurality of temperature collection units are arranged on the bottom surface of the heat sink, and one of the temperature collection units is close to the maximum power device of the photovoltaic inverter.

[0031] From the above description, it can be seen that by setting up multiple temperature collection units to perform multi-point collection of the radiator, the local hotter temperature of the radiator can be collected under different working conditions, avoiding local overheating and damage to the inverter when a single fan or multiple fans fail.

[0032] Furthermore, the fan group is located on one side of the radiator with the air outlet facing the radiator, and the other side of the radiator is used to place the boost inductor and the filter inductor of the photovoltaic inverter.

[0033] It can be seen from the above description that after the fan group is turned on, the radiator, the boost inductor and the filter inductor are all cooled by air.

[0034] Furthermore, the temperature acquisition unit is an NTC thermistor.

[0035] From the above description, it can be seen that a preferred implementation of a temperature acquisition unit is provided.

[0036] Furthermore, a plurality of evenly distributed heat dissipation holes are provided on the side of the heat dissipation chamber housing.

[0037] From the above description, it can be seen that heat is dissipated through the heat dissipation holes and external ventilation.

[0038] Please refer to Figures 3 to 6 , a heat dissipation control method for a photovoltaic inverter comprises the following steps:

[0039] S1, receiving the real-time temperature value of the radiator collected by the temperature collection unit;

[0040] S2, judging whether all fans of the fan group are faulty, if all fans of the fan group are not faulty, entering the temperature control mode, otherwise judging whether the number of fans with faults in the fan group is greater than 1, if so, reducing the maximum output power of the photovoltaic inverter and then entering the temperature control mode, otherwise directly entering the temperature control mode, the temperature control mode is to control the operation state of the fan group according to the real-time temperature value of the radiator;

[0041] S3, controlling the fan group to perform air cooling on the radiator and power devices of the photovoltaic inverter.

[0042] From the above description, it can be seen that the beneficial effects of the present invention are: the temperature of the radiator is collected by a temperature collection unit, and multiple fans are provided for air cooling and heat dissipation, so that when one of the fans fails, there is no need to directly reduce the output power of the photovoltaic inverter because there are other fans that can perform air cooling and heat dissipation, thereby improving the power generation efficiency and reliability of the photovoltaic inverter; at the same time, the operating state of the fan group is controlled according to the real-time temperature value of the radiator to avoid the phenomenon of turning on the fan in a low temperature environment or the fan being in a high speed state in a low temperature environment, thereby providing a heat dissipation control method with high power generation efficiency, more energy-saving control method and increased fan life.

[0043] Furthermore, the step S1 specifically includes the following steps:

[0044] The real-time temperature value of the environment, the real-time temperature values ​​of the radiator collected by multiple temperature collection units arranged at different positions of the radiator, and the real-time temperature value of the power device collected by the temperature collection unit provided in each power device are received.

[0045] From the above description, it can be seen that by setting up multiple temperature acquisition units, multi-point acquisition of the radiator is performed. At the same time, the temperature acquisition unit inside each power device collects the temperature of each power device to achieve multi-point acquisition of the power devices, thereby avoiding local overheating and damage to the inverter when a single fan or multiple fans fail.

[0046] Furthermore, the temperature control mode of step S2 specifically includes the following steps:

[0047] S21, determining whether the real-time temperature value of the radiator is higher than a first radiator temperature threshold value, if so, executing step S22, otherwise executing step S23;

[0048] S22, judging whether the real-time temperature value of the radiator is higher than or equal to the second radiator temperature threshold value, or whether the real-time temperature value of the power device is higher than or equal to the first power device temperature threshold value, or whether the real-time temperature value of the environment is higher than or equal to the first environment temperature threshold value; if so, reducing the maximum output power of the photovoltaic inverter, and then executing step S24; otherwise, controlling the lifting and lowering gears of the fan group according to the real-time temperature value of the radiator, and the second radiator temperature threshold value is greater than the first radiator temperature threshold value;

[0049] S23, determining whether the real-time temperature value of the radiator is higher than a fourth radiator temperature threshold value, if so, maintaining the rotation speed of the fan group at the current gear, otherwise turning off the fan group, and the first radiator temperature threshold value is greater than the fourth radiator temperature threshold value;

[0050] S24. Determine whether the real-time temperature value of the radiator is higher than or equal to the third radiator temperature threshold, or whether the real-time temperature value of the power device is higher than or equal to the second power device temperature threshold, or whether the real-time temperature value of the environment is higher than or equal to the second ambient temperature threshold. If so, control the photovoltaic inverter to shut down, report an over-temperature fault, and return to the standby state. The third radiator temperature threshold is greater than the second radiator temperature threshold, the second power device temperature threshold is greater than the first power device temperature threshold, and the second ambient temperature threshold is greater than the first ambient temperature threshold.

[0051] From the above description, it can be seen that by setting two levels of over-temperature protection, when one of the real-time temperatures reaches the first level temperature limit, the inverter output begins to derate. If it reaches the second level limit, the inverter is directly shut down to cover the temperature limit protection under different working conditions; at the same time, when a fan fails, if it is in a medium or low temperature environment, the inverter is guaranteed to operate at full load; only under extreme conditions will derated operation occur, which minimizes the loss of power generation and leaves sufficient time to repair the inverter, thereby ensuring the power generation efficiency and safety of the inverter.

[0052] Furthermore, in step S22, controlling the fan group to change gears according to the real-time temperature value of the radiator specifically includes the following steps:

[0053] After the real-time temperature value of the radiator reaches the first radiator temperature threshold for the first time, the fan is turned on to the lowest gear. Thereafter, every time the real-time temperature value of the radiator rises by a preset gear threshold, the fan group is controlled to increase one gear to increase the fan speed until the fan gear reaches the highest gear. Every time the real-time temperature value of the radiator drops by the preset gear threshold, the fan group is controlled to decrease one gear to reduce the fan speed until the fan gear drops to the lowest gear.

[0054] From the above description, it can be seen that by presetting the gear threshold and the corresponding multi-speed fan speed, more precise heat dissipation control can be achieved without the need for frequent control.

[0055] Furthermore, the following steps are included between step S1 and step S2:

[0056] Determine whether the temperature difference among the real-time temperature value of the radiator, the real-time temperature value of the power device and the real-time temperature value of the environment and their respective corresponding absolute values ​​are within a preset normal range. If so, execute step S2; otherwise, reduce the maximum output power of the photovoltaic inverter and then enter a power control mode. The power control mode controls the operating state of the fan group according to the real-time output power of the photovoltaic inverter.

[0057] From the above description, it can be seen that the temperature self-check function is set. When the temperature collection data is abnormal, the output power debugging mode is used to ensure that heat dissipation control can be performed under any working conditions.

[0058] Please refer to Figure 1 to Figure 2 , Embodiment 1 of the present invention is:

[0059] The heat dissipation device of the photovoltaic inverter includes a heat dissipation chamber casing 1, a control unit, a fan group 2, a radiator 3 and a temperature collection unit 4, wherein the control unit is electrically connected to the fan group 2, the radiator 3 and the temperature collection unit 4 in a one-to-one correspondence; wherein the radiator 3 and the fan group 2 are located on the heat dissipation chamber casing 1, the temperature collection unit 4 and the fan group 2 are both arranged at any position close to the radiator 3, and the radiator 3 is arranged adjacent to the power device of the photovoltaic inverter.

[0060] In this embodiment, at least two fans 21 are provided in the fan group 2. Figure 1 and 2 Four fans 21 are shown. Thus, when one of the fans 21 fails, there are other fans 21 available for air cooling and heat dissipation. Therefore, there is no need to directly reduce the output power of the photovoltaic inverter, thereby improving the power generation efficiency of the photovoltaic inverter.

[0061] In this embodiment, if Figure 1 It can be seen that the radiator 3 is connected to one side of the heat dissipation chamber housing 1, and the other three sides of the radiator 3 are respectively placed with the fan group 2, the boost inductor 101 of the photovoltaic inverter, and the filter inductor 102. Among them, the filter inductor 102 is the filtering function of the inverter side, the boost inductor 101 is the DC boost inductor 101 of the photovoltaic side, the air outlet of the fan group 2 faces the radiator 3, and the side of the heat dissipation chamber housing 1 is provided with a plurality of evenly distributed heat dissipation holes 11, so that after the fan group 2 is turned on, the radiator 3, the boost inductor 101 and the filter inductor 102 are all cooled by air.

[0062] In this embodiment, if Figure 2 It can be seen that multiple temperature acquisition units 4 are arranged on the bottom surface of the radiator 3, one of which is close to the maximum power device 100 of the photovoltaic inverter. At the same time, the temperature acquisition unit 4 is an NTC thermistor. At the same time, the power device of the photovoltaic inverter itself has an NTC thermistor inside, which can be connected to the control unit through the wiring of the PCB board, so that the control unit can receive the real-time temperature of the power device, that is, multi-point acquisition of the radiator 3 and multi-point acquisition of the power device is realized, avoiding local overheating and damage to the inverter when a single fan 21 or multiple fans 21 fail.

[0063] The following embodiments are provided for the control method implemented by the heat dissipation device of the photovoltaic inverter of this embodiment.

[0064] Please refer to Figures 3 to 6 , Embodiment 2 of the present invention is:

[0065] The heat dissipation control method of the photovoltaic inverter is controlled by the control unit 5 in the above-mentioned embodiment 1, and comprises the following steps:

[0066] S1, receiving the real-time temperature value of the radiator collected by the temperature collection unit;

[0067] In this embodiment, if Figure 4 As shown, step S1 specifically includes the following steps: receiving the real-time temperature value of the environment, the real-time temperature values ​​of the radiator respectively collected by multiple temperature collection units arranged at different positions of the radiator, and the real-time temperature value of the power device respectively collected by the temperature collection unit provided in each power device, that is, realizing multi-point collection of the radiator and multi-point collection of the power device, avoiding local overheating and damage to the inverter when a single fan or multiple fans fail.

[0068] like Figure 5 As shown, the following steps are also included between step S1 and step S2:

[0069] It is determined whether the temperature difference between the real-time temperature value of the radiator, the real-time temperature value of the power device and the real-time temperature value of the environment and their corresponding absolute values ​​are within the preset normal range. If so, step S2 is executed. Otherwise, the maximum output power of the photovoltaic inverter is reduced and then the power control mode is entered. The power control mode controls the operation state of the fan group 2 according to the real-time output power of the photovoltaic inverter. That is, the temperature self-check function is set. When the temperature collection data is abnormal, the output power debugging mode is used to ensure that heat dissipation control can be performed under any working conditions.

[0070] S2, determine whether all fans of fan group 2 are faulty. If all fans of fan group 2 are not faulty, enter the temperature control mode. Otherwise, determine whether the number of fans with faults in fan group 2 is greater than 1. If so, reduce the maximum output power of the photovoltaic inverter and then enter the temperature control mode. Otherwise, directly enter the temperature control mode. The temperature control mode controls the operating state of fan group 2 according to the real-time temperature value of the radiator. Therefore, when one of the fans fails, there is no need to directly reduce the output power of the photovoltaic inverter to improve the power generation efficiency of the photovoltaic inverter.

[0071] like Figure 6 As shown, the temperature control mode of step S2 specifically includes the following steps:

[0072] S21, determine whether the real-time temperature value of the radiator is higher than the first radiator temperature threshold value, if so, execute step S22, otherwise execute step S23, wherein, in this embodiment, if Figure 6 As shown, it is assumed that the first heat sink temperature threshold is 50°C;

[0073] S22, determine whether the real-time temperature value of the radiator is higher than or equal to the second radiator temperature threshold value or whether the real-time temperature value of the power device is higher than or equal to the first power device temperature threshold value or whether the real-time temperature value of the environment is higher than or equal to the first environment temperature threshold value, if so, reduce the maximum output power of the photovoltaic inverter, and then execute step S24, otherwise control the lifting and lowering gears of the fan group 2 according to the real-time temperature value of the radiator, the second radiator temperature threshold value is greater than the first radiator temperature threshold value, wherein, in this embodiment, if Figure 6 As shown, the second heat sink temperature threshold is 80°C, the first power device temperature threshold is 95°C, and the first ambient temperature threshold is 80°C, so as to provide the first gear over-temperature protection;

[0074] Among them, in step S22, controlling the fan group 2 to change gears according to the real-time temperature value of the radiator specifically includes the following steps:

[0075] After the real-time temperature value of the radiator reaches 50°C for the first time, the fan is turned on at the lowest gear. Thereafter, every time the real-time temperature value of the radiator rises by a preset gear threshold, the fan group 2 is controlled to increase one gear to increase the fan speed until the fan reaches the highest gear. Every time the real-time temperature value of the radiator drops by a preset gear threshold, the fan group 2 is controlled to decrease one gear to reduce the fan speed until the fan reaches the lowest gear. In this embodiment, Figure 6 As shown, the preset gear threshold is 5°C, that is, as the radiator temperature increases, the fan speed is gradually increased, and vice versa, so as to achieve more precise heat dissipation control without frequent control;

[0076] That is, in this embodiment, when a fan failure occurs, the inverter is guaranteed to operate at full load in a medium to low temperature environment; only under extreme operating conditions will the inverter be operated at a reduced rating to minimize power generation losses and leave sufficient time to repair the inverter, thereby ensuring the power generation efficiency and safety of the inverter.

[0077] S23, determine whether the real-time temperature value of the radiator is higher than the fourth radiator temperature threshold value, if so, maintain the speed of fan group 2 at the current gear, otherwise turn off fan group 2, the first radiator temperature threshold value is greater than the fourth radiator temperature threshold value, wherein, in this embodiment, if Figure 6 As shown, the fourth radiator temperature threshold is 35°C. Thus, if the radiator temperature returns from above 50°C to between 35°C and 50°C, it is only necessary to maintain the current gear, i.e., the lowest gear, and directly turn off the fan when it is below 35°C. If the radiator temperature does not exceed 50°C after the inverter is turned on, the fan is still not turned on when it is between 35°C and 50°C, thereby avoiding the phenomenon of turning on the fan in a low temperature environment or the fan being in a high speed state in a low temperature environment.

[0078] S24, determine whether the real-time temperature value of the radiator is higher than or equal to the third radiator temperature threshold or whether the real-time temperature value of the power device is higher than or equal to the second power device temperature threshold or whether the real-time temperature value of the environment is higher than or equal to the second environment temperature threshold, if so, control the photovoltaic inverter to shut down, report an over-temperature fault, and return to the standby state, the third radiator temperature threshold is greater than the second radiator temperature threshold, the second power device temperature threshold is greater than the first power device temperature threshold, and the second environment temperature threshold is greater than the first environment temperature threshold, wherein, in this embodiment, if Figure 6 As shown, the second heat sink temperature threshold is 85° C., the first power device temperature threshold is 100° C., and the first ambient temperature threshold is 85° C., so as to provide a second level of over-temperature protection.

[0079] S3, controlling the fan group 2 to perform air cooling on the radiator and the power devices of the photovoltaic inverter, that is, controlling the operation of the fan group 2 according to the above control instructions, thereby performing air cooling on the radiator and the power devices of the photovoltaic inverter.

[0080] In summary, the heat dissipation device and control method of the photovoltaic inverter provided by the present invention, by performing multi-point collection of the radiator and multi-point collection of the power device, avoids local overheating and damage to the inverter when a single fan or multiple fans fail; by providing multiple fans for air cooling and heat dissipation, when a fan fails, if it is in a medium or low temperature environment, the inverter is guaranteed to operate at full load; only under extreme working conditions will the derating operation occur, the power generation loss is reduced to a minimum, and sufficient time is left to repair the inverter, thereby ensuring the power generation efficiency and safety of the inverter; at the same time, the operation state of the fan group is controlled according to the real-time temperature value of the radiator. To avoid the phenomenon of turning on the fan in a low temperature environment or the fan being in a high speed state in a low temperature environment, two-speed over-temperature protection is set to cover the temperature limit protection under different working conditions; by presetting the gear threshold and the corresponding multi-speed fan speed, more precise heat dissipation control can be achieved without the need for frequent control. By setting the temperature self-check function, when the temperature collection data is abnormal, the output power debugging mode is used to ensure that heat dissipation control can be performed under any working conditions, thereby providing a heat dissipation control method with high power generation efficiency, high safety level, more precise and energy-saving control method, wider range of working conditions and increased fan life.

[0081] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A heat dissipation control method for a photovoltaic inverter, characterized in that: The following steps are involved: S1, receiving the real-time temperature value of the radiator collected by the temperature collection unit; S2, judging whether all fans of the fan group are faulty, if all fans of the fan group are not faulty, entering the temperature control mode, otherwise judging whether the number of fans with faults in the fan group is greater than 1, if so, reducing the maximum output power of the photovoltaic inverter and then entering the temperature control mode, otherwise directly entering the temperature control mode, the temperature control mode is to control the operation state of the fan group according to the real-time temperature value of the radiator; S3, controlling the fan group to perform air cooling on the radiator and the power devices of the photovoltaic inverter; Receive the real-time temperature value of the environment, the real-time temperature values ​​of the radiator collected by multiple temperature collection units arranged at different positions of the radiator, and the real-time temperature value of the power device collected by the temperature collection unit provided in each power device; The temperature control mode of step S2 specifically includes the following steps: S21, determining whether the real-time temperature value of the radiator is higher than a first radiator temperature threshold value, if so, executing step S22, otherwise executing step S23; S22, judging whether the real-time temperature value of the radiator is higher than or equal to the second radiator temperature threshold value, or whether the real-time temperature value of the power device is higher than or equal to the first power device temperature threshold value, or whether the real-time temperature value of the environment is higher than or equal to the first environment temperature threshold value; if so, reducing the maximum output power of the photovoltaic inverter, and then executing step S24; otherwise, controlling the lifting and lowering gears of the fan group according to the real-time temperature value of the radiator, and the second radiator temperature threshold value is greater than the first radiator temperature threshold value; S23, determining whether the real-time temperature value of the radiator is higher than a fourth radiator temperature threshold value, if so, maintaining the rotation speed of the fan group at the current gear, otherwise turning off the fan group, and the first radiator temperature threshold value is greater than the fourth radiator temperature threshold value; S24. Determine whether the real-time temperature value of the radiator is higher than or equal to the third radiator temperature threshold, or whether the real-time temperature value of the power device is higher than or equal to the second power device temperature threshold, or whether the real-time temperature value of the environment is higher than or equal to the second ambient temperature threshold. If so, control the photovoltaic inverter to shut down, report an over-temperature fault, and return to the standby state. The third radiator temperature threshold is greater than the second radiator temperature threshold, the second power device temperature threshold is greater than the first power device temperature threshold, and the second ambient temperature threshold is greater than the first ambient temperature threshold.

2. The heat dissipation control method of a photovoltaic inverter according to claim 1, characterized in that: The step S22 of controlling the fan group to move up and down according to the real-time temperature value of the radiator specifically includes the following steps: The fan is turned on at the lowest gear only when the real-time temperature value of the radiator is higher than the first radiator temperature threshold for the first time. Thereafter, every time the real-time temperature value of the radiator rises by a preset gear threshold, the fan group is controlled to increase one gear to increase the fan speed until the fan group reaches the highest gear. Every time the real-time temperature value of the radiator drops by the preset gear threshold, the fan group is controlled to decrease one gear to reduce the fan speed until the fan group drops to the lowest gear.

3. The heat dissipation control method of a photovoltaic inverter according to claim 1, characterized in that: The following steps are also included between step S1 and step S2: Determine whether the temperature difference among the real-time temperature value of the radiator, the real-time temperature value of the power device and the real-time temperature value of the environment and their respective corresponding absolute values ​​are within a preset normal range. If so, execute step S2; otherwise, reduce the maximum output power of the photovoltaic inverter and then enter a power control mode. The power control mode controls the operating state of the fan group according to the real-time output power of the photovoltaic inverter.

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