The structure protection design of photovoltaic inverter
With the rapid development of new energy industry, photovoltaic power generation applications are more and more widely, and photovoltaic inverters are a key component of photovoltaic power generation systems. Most inverters operate in outdoor environments and are subject to very harsh and even harsh environments. test.
For outdoor-operated PV inverters, the structural design must meet the IP65 rating. Only by meeting this standard can our inverters work safely and efficiently. The IP rating is the degree of protection against foreign matter intrusion in the electrical equipment enclosure. The source is the International Electrotechnical Commission's standard IEC60529, which was also adopted as the US national standard in 2004. We often say the IP65 grade, IP is the abbreviation of IngressProtection, of which 6 is dustproof, (6: completely prevent dust from entering); 5 is waterproof, (5: no damage to the product with water).
In order to meet the above design requirements, the structural design requirements of photovoltaic inverters are very strict and prudent, which is also a very easy problem in field applications. So how do we design a qualified inverter product?
At present, there are two main types of protection design between the upper cover and the cabinet of the inverter: one is the silicone waterproof ring, which is generally 2mm thick, through the upper cover and the box. Pressing is waterproof and dustproof. This kind of protection design is limited by the deformation amount and hardness of the silicone waterproof ring. It is only suitable for the 1-2KW small inverter box. The larger the box, the protection effect has more hidden dangers.
As shown in the following schematic <1>:
The other is protected by the German blue urethane (RAMPF) urethane foam, which is molded by CNC foam and directly bonded to the structural parts such as the upper cover, and its deformation can reach 50%. Above, it is especially suitable for the protection design of our medium and large inverters.
As shown in the following diagram <2>:
At the same time, more importantly, in the structural design, in order to ensure high-strength waterproof design, a waterproof tank should be designed between the upper cover and the box of the PV inverter chassis to ensure that even if there is water mist passing through the upper cover and the box Entering the inverter between the bodies will also guide the water droplets out of the outside through the waterproof tank, and avoid entering the cabinet.
In recent years, the photovoltaic market has been highly competitive. Some inverter manufacturers have made some simplifications and substitutions from the protection design and material use in order to control the cost. For example, as shown in the following diagram <3>:
The left side is a design that reduces the cost. The box body adopts a bending, and the cost is controlled from the sheet metal material and the process. Compared with the three bending boxes on the right side, there is obviously one less guiding groove. The strength of the body is also much lower. These designs bring great hidden dangers to the waterproof performance of the inverter.
In addition, since the inverter cabinet design achieves the IP65 protection level, and the internal temperature of the inverter increases during operation, the pressure difference caused by the internal high temperature and the external environmental conditions will cause the pressure difference. Moisture enters and damages sensitive electronic components. In order to avoid this problem, we usually install a waterproof and breathable valve on the inverter box. The waterproof and breathable valve can effectively balance the pressure and reduce the condensation in the closed equipment, while blocking the entry of dust and liquid. Thereby improving the safety, reliability and service life of the inverter products.
Therefore, we can see that a qualified PV inverter structure design must be carefully designed and selected from the chassis structure design scheme or the materials used. Otherwise, it is reduced in order to control the cost. The design requirements can only bring great hidden dangers to the long-term stable operation of the PV inverter.
About Natong
Changzhou Jiaxun Optoelectronic Industry Development Co., Ltd., established in 1994, is mainly engaged in the design, installation and maintenance of photovoltaic grid-connected inverter production and photovoltaic system engineering. It has Grade B qualification for new energy power generation design (highest qualification for new energy design), The power engineering construction general contracting three-level qualification, mechanical and electrical equipment installation engineering professional contracting three-level qualification, is also the National Ministry of Industry and Information Technology list inverter finalists.
Jiangsu Jiaxun Natong Energy Technology Co., Ltd., a subsidiary of Changzhou Jiaxun, specializes in providing advanced string inverters, energy storage converter products and integrated intelligent energy management systems for distributed generation systems and microgrid systems. Program. At the same time, considering the post-photovoltaic market, the company established a new “photovoltaic power station operation and maintenance management platform center†in 2016, which continues to innovate based on customer needs and continues to expand in several areas such as photovoltaic energy Internet, mobile Internet of things, cloud computing and big data. . With experience in operation and maintenance management of several centralized and distributed PV power plant projects around the world, Natong Energy has the strength to manage the operation and maintenance of photovoltaic power generation.
At present, Natong Energy has initially developed into a comprehensive energy technology company integrating “core equipment products, power station intelligent operation and maintenance, and intelligent energy managementâ€.
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