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Talking about the structural protection design of photovoltaic inverter

Dec 19, 2020

Talking about the structural protection design of photovoltaic inverter

With the rapid development of the new energy industry, photovoltaic power generation applications are becoming more and more extensive, and photovoltaic inverters are a key component of photovoltaic power generation systems. Most inverters operate in outdoor environments and have to withstand very harsh or even harsh environments. test.

For outdoor photovoltaic inverters, their structural design must meet the IP65 level standard. Only by reaching this standard can our inverters work safely and efficiently. The IP rating is the degree of protection against the intrusion of foreign objects in the enclosure of electrical equipment. The source is the standard IEC 60529 of the International Electrotechnical Commission, which was also adopted as the American national standard in 2004. The IP65 level we often say, IP is the abbreviation of Ingress Protection, where 6 is the dustproof level, (6: completely prevents dust from entering); 5 is the waterproof level, (5: water washing does not harm the product).

In order to meet the above design requirements, the structural design requirements of photovoltaic inverters are very strict and prudent, which is also a place that is very prone to problems in field applications. So how do we design a qualified inverter product?

At present, there are two common protection design methods between the inverter upper cover and the cabinet in the industry: one is to use a silicone waterproof ring. This silicone waterproof ring is generally 2mm thick and passes through the upper cover and the cabinet. Pressing to achieve the effect of waterproof and dustproof. This kind of protection design is limited by the deformation of the silicone waterproof ring and the hardness of the material. It is only suitable for inverter cabinets with a size of 1-2KW. A larger cabinet has more hidden dangers in its protective effect.

The other is protected by RAMPF polyurethane foam. This polyurethane foam is formed by CNC foaming, directly bonded to the upper cover and other structural parts, and its deformation can reach 50% The above is especially suitable for the protection design of our medium and large inverters.

At the same time, more importantly, in the structural design, in order to ensure a high-strength waterproof design, a waterproof groove must be designed between the upper cover and the box body of the photovoltaic inverter chassis to ensure that even if water mist passes through the upper cover and the box If the inverter enters between the inverters, the water droplets will also be guided out of the exterior through the waterproof groove, so as to avoid entering the cabinet.

In recent years, competition in the photovoltaic market has been fierce. In order to control costs, some inverter manufacturers have simplified and replaced the protection design and material use.

This is a cost-reducing design. The box body adopts one bending, and the cost is controlled from the sheet metal material and process. Compared with the other three-fold bending box body, there is obviously one less guide groove. The strength of the cabinet is also much lower, and these designs have brought great hidden dangers to the waterproof performance of the inverter.

In addition, because the inverter cabinet design has reached the IP65 protection level, the internal temperature of the inverter will rise during operation, so the pressure difference caused by the higher internal temperature and the changing external environmental conditions will cause Moisture enters and damages sensitive electronic components. In order to avoid this problem, we usually install a waterproof breather valve on the inverter box. The waterproof breather valve can effectively equalize the pressure and reduce condensation in the closed equipment, while blocking the entry of dust and liquid. Thereby improving the safety, reliability and service life of inverter products.

Therefore, we can see that the structural design of a qualified photovoltaic inverter must be carefully and strictly designed and selected in terms of the chassis structure design and the materials used. Otherwise, the cost will be reduced blindly. The design requirements can only bring great hidden dangers to the long-term stable operation of the photovoltaic inverter.