Innovation of the “leader”: Central inverters that come out of the house

Inverter that lives in the house

Open up the "Ren and Du Meridians" and achieve IP65 protection for key components

Go out of the house to adapt to various application environments such as water surface, dust, salt spray, etc.

2.5MW solution optimal outdoor central inverter future development trend

Looking back at the history of the development of the photovoltaic industry, from the "franchise" bidding in 2009 that kicked off the application of centralized inverters, to centralized inverters becoming the mainstream product for large-scale ground photovoltaic power stations in China and even the world, the performance indicators of centralized inverters have been continuously improved. At the same time, the protection performance has become stronger and stronger, gradually getting rid of the constraints of the house and directly applied outdoors. How is this technology achieved? What is the application environment? What value can it bring to the owner? Let's listen to the editor's story.

Inverter that lives in the house

From the perspective of application and installation methods, the development of central inverters has gone through three milestones: before 2008, central inverters were housed in cement houses; from 2008 to 2012, central inverters were moved to outdoor board houses; from 2013 to the present, central inverters have been moved to containers.

Looking at the development history of centralized inverter applications, there is a very obvious feature, that is, the inverter is always inseparable from the house in practical applications. This is the same reason why people live in houses, just to give the inverter better protection and a better working environment. Friends who like to think will definitely raise a question: with the development of technology, can centralized inverters be separated from houses?

Who is the inverter house built for?

The protection level of a general centralized inverter is IP21, and it can be placed in a house to achieve an IP54 protection level to meet the requirements of actual working conditions. The high protection level of IP54 is mainly to protect the core precision components of the inverter, such as IGBT, electronic components, circuit boards, etc., to prevent moisture, dust, etc. from contacting them. When the protection level of the inverter itself reaches IP54 or above, you can go out of the house, which is the fourth milestone of the centralized inverter.

As we all know, although the conversion efficiency of central inverters has exceeded 99%, there is still 1% loss in the form of heat. In order to dissipate the heat from the body, there needs to be an internal and external exchange of air, and the air contains moisture and dust, so the internal and external exchange of air will bring challenges to the protection level, which is a certain contradiction.

Open up the "Ren and Du Meridians" and achieve IP65 protection for key components

To solve this problem, we can innovate in structural design and thermal design, so that the heat dissipation airflow can bring the internal heat out of the body in time, and prevent moisture and dust in the heat dissipation airflow from contacting the core precision components we want to protect. This requires designing the airflow path, just like opening up the "Ren and Du meridians" of the centralized inverter.

The Ren Meridian is the external circulation, and the Du Meridian is the internal circulation. The control board, low-voltage components, capacitors, etc. are located inside a completely sealed cabinet, and heat is exchanged with the outside through the heat exchanger's heat dissipation aluminum foil. The specific heat exchange process is: the external cold air enters from the air inlet, passes through the heat exchanger's heat dissipation aluminum foil, and then comes out from the upper exhaust port; the internal circulation heat is transferred to the external circulation through the heat exchanger's heat dissipation aluminum foil, achieving complete isolation between the inside and the outside.

Such an ingenious and innovative design not only ensures that the internal heat can be dissipated as quickly as possible, but also completely isolates the core components of the inverter from external water vapor and dust, achieving IP65 protection and providing a clean and comfortable working environment. This makes the inverter more stable and reliable, and its lifespan will be longer.

Get out of the house and adapt to various application environments such as water surface, dust, salt spray, etc.

Sungrow released the country's first outdoor stand-alone central inverter SG1250 at this year's SNEC exhibition, taking the lead in China to bring central inverters out of houses. It can be directly used outdoors in various harsh environments such as high temperature, high humidity, wind, sand, salt spray, such as water power stations, desert power stations and saline-alkali power stations.

In addition to inheriting all the advantages of traditional central inverters, such as SVG function, PID repair and protection, intelligent control unit, etc., this outdoor central inverter has also been comprehensively upgraded and optimized: it has a higher cost-effectiveness, a smaller footprint, a higher power density, and more advantages in reliability and maintenance, which greatly reduces the system's initial investment and operation and maintenance costs.

In actual applications, it is recommended to use two SG1250s to form a 2.5MW inverter unit, which has the best system cost performance: compared with the string-type 1.6MW solution, it saves about 2 cents/W in initial investment; compared with the centralized 1.25MW solution, it saves about 5 cents/W in initial investment.