As a power electronic device, the main function of a PV inverter is to convert the DC power generated by PV modules into AC power. Since there are thousands of electronic components inside, and most of them are heat-source devices, the thermal design has a great impact on the life of the inverter. However, not all users are aware of this, so we often receive questions such as, "An inverter device installed on my roof has a hot surface, is there something wrong with the inverter?" "Is the inverter going to explode?" And so on. The answer is of course not, we will explain it to you through the analysis of the mainstream thermal solution and the third-party TUV data report.
With the development of PV inverter technology and the improvement of efficiency, its heat dissipation form has changed from the initial all fan heat dissipation to the following 3 mainstream heat dissipation designs.
1. Integrated die-casting mold fanless design
Advantage: Firstly, the integrated heat dissipation of the upper and lower parts of the mold shell not only greatly increases the heat dissipation area, but also greatly reduces the heat transfer impedance; secondly, the internal heat source devices can dissipate heat extremely well, which not only ensures balanced heat dissipation inside and outside the inverter, but also makes all kinds of devices in the best working condition.
Disadvantage: For products with high power density and fanless design, customers have misconceptions. It is believed that insufficient heat dissipation of the devices will lead to lower power generation and affect the life of the inverter.
Representative model 1: H manufacturer inverter. The internal temperature of the inverter is the same as the temperature of the chassis shell, and the internal temperature is about 55 degrees under the ambient temperature of 45 degrees.
Representative model 2: Y manufacturer inverter. The internal temperature of the inverter is the same as that of the case, and the internal temperature is about 60 degrees under the ambient temperature of 45 degrees.
Option 2: Ordinary sheet metal external fan design
Advantage: lower surface temperature of the chassis.
Disadvantage: The inverter heat sink is small in size, and although some of the heat from the internal heat source devices can be taken away by the fan, the whole heat source devices do not dissipate heat evenly. Not only that, this inverter also has the problem of high heat dissipation impedance between the outer case and the internal heat source device, so that the internal heat is not easily transferred to the surface of the case, thus making the temperature of the internal device much higher than the surface of the case, which may cause the equipment to work at a reduced level or the life of the internal device to be reduced by long-term heat;.
Representative model 1: S manufacturer inverter. The internal temperature of the inverter is about 15 degrees higher than that of the chassis shell, and the internal temperature is about 65 degrees under the ambient temperature of 45 degrees.
Representative model 2: S manufacturer inverter. The internal temperature of the inverter is about 15 degrees higher than that of the chassis casing, and the internal temperature is about 70 degrees under the ambient temperature of 45 degrees.
Option 3: Ordinary sheet metal fanless design
Advantage: internal heat flow exchange design, which allows rapid heat flow from internal heat source devices to the inverter surface.
Disadvantage: the housing is designed by non-diecasting mold, the heat dissipation impedance and heat dissipation area are inferior to die-casting mold products, not only the surface temperature of the inverter is high, but it needs a bigger heat sink (increase the volume of the case) to do the support.
Representative model 1: G manufacturer inverter. The internal temperature of the inverter is about 15 degrees lower than that of the chassis shell. Under the ambient temperature of 45 degrees, the internal temperature is about 55 degrees, but the surface temperature is as high as about 75 degrees.
