Recently, I received a message from a friend in the countryside that he wanted to install rooftop pv inverter on his roof. However, when choosing the inverter, he fell into the "obsessive choice".
He was first on the net compared with the price, the same brand price difference hundreds, and did not find the official flagship store; and then in the circle of friends consulted a few, several agents say that they are XX manufacturers directly take goods in the general generation, but a place has several general generation, choose who? But when we contacted several manufacturers, each family said they were better than the other side, and their advantages were listed in a lot. But which one was better? Finally, we found the biggest brand inverter company, but when the other side heard that only a 5KW, simply say you contact the XX area agent!
After a lot of trial and error, the friend felt uncomfortable. Why is it so hard for us in the countryside to choose a inverter?
In fact, there are some tips to choose the inverter in the photovoltaic system. Consider these aspects: cost, efficiency, and operational characteristics.
First, cost often determines people\'s choice of space
For rural users, the construction of pv system is not fashionable and fresh. Most of them are considered from the perspective of financial investment. This also provides an opportunity for individual businesses to bring cheap inverters to market in order to own the market. It doesn\'t hurt to be cheap, as long as it\'s not built on low quality. But in reality, cheap is often equated with low quality.
For the pv inverters of the household system, they are all series inverters, which are small in size and light in weight. They are very convenient in handling and installation, do not need professional equipment and tools, and do not need a power distribution room.
Its cost is not external, so where is it? It is certain that inside it, the inverter is composed of many components, such as IGBT, fuse, capacitor, sensor, relay, diode, microprocessor, segment, resistance, etc. Don\'t underestimate that the components of these components vary greatly from brand to brand. In addition, the inverter\'s panel processing mode, the size of the display screen is also very different.
Second, efficiency is the king of the photovoltaic power generation era, inverter efficiency to see so!
When writing this article, we also consulted the mainstream inverter manufacturers in the industry. According to the publicity above, the maximum efficiency of each company can reach 95% or even higher. High efficiency of inverter is the basic guarantee of pv power generation and user income. The difference of efficiency of different brands of inverter is mainly about system optimization and line loss. User system commonly used group series inverter, battery string input of each group to an inverter, the inverter and battery of input string independently MPPT, ensure that each set of string maximum power, even if a particular set of string caused by a lack of solar radiation or disconnected because of malfunction, the other set of string is not affected also continue to normal power.
In practice, the only indicator of the efficiency of the inverter is the amount of power generation. There is a EPC enterprise to compare two different brands of inverters, often with the same board and a same power inverter, but this comparison is a method, but it is not absolutely accurate. Here we only say a point, inverter screen The power output displayed can be operated artificially, and the efficiency can also be controlled by software. The most accurate one is based on the meter. This is also why users are wondering why the numbers on the inverter screen are different from those on the meter. Of course, such a situation is not very common, but don\'t make a fuss when you encounter it. So when choosing contrast, we need to find a suitable method for efficiency comparison.
Third, mastering the operation characteristics of inverter will enhance the life and power generation of the inverter.
As we mentioned above, the inverter is composed of so many components. The performance of these components determines the performance of the inverter. Inverters in household systems generally have IP65 protection level, but it is not unexpected that it "knife and gun can not enter", "non-toxic and non-invasive".
The operation of the inverter is a process of exothermic. In the process of generating electricity constantly, there is a lot of heat generated. This requires sufficient convection space around the inverter to dissipate the heat around the inverter. The system used by the household is usually based on natural heat dissipation, and does not match the fan.Large and medium sized inverters are often equipped with cooling fans.
Although the inverter has IP65 protection level, when you expose it for a long time in harsh environment, it also affects its service life and power generation capacity. If you want the inverter to run steadily for 10 years and 20 years, it is essential for its "love". Although the inverter room will not be configured in the household system, it will not be exposed to the natural, usually to the top of a sunshade.
Fourth, complete certification can be an alternative standard.
No matter the inverter is exported abroad or sold in China, the country has strict standards for it. In China, the most authoritative one is CQC certification.
Overall photovoltaic inverter to choose according to actual situation of the users to install inverter, not only can save the engineering cost, simplify the installation conditions, shorten the cycle of installation, and can effectively improve the efficiency of power generation system, summarized as the principle of efficient, reliable, low cost, these three are closely together, a certain problems, for the whole system will appear "short legs" phenomenon, more to understand "one point price one point goods" market rules.
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