The most important component of photovoltaic power generation is the inverter. If your photovoltaic power generation efficiency is getting lower and lower, or even lower than other photovoltaic power generation equipment with the same configuration, then it is very likely that your transformer has broken down. What are the most likely places to break down? Let us know about the dimension.
The photovoltaic inverter is composed of circuit board, fuse, power switch tube, inductance, relay, capacitor, display screen, fan, radiator, structure and other components. The life of each component is different. The life of the inverter can be explained by the "bucket theory". The maximum capacity of the bucket is determined by the shortest wooden board. The life of the inverter is determined by the shortest components. The most likely failure of the inverter is the power switch tube, capacitor, display screen and fan. .
Power switch tube
Power switch tube is the main device to convert DC to AC, and is the heart of inverter.
IGBT, MOSET and so on are the most vulnerable components of the inverter, which have three fears: one fears overvoltage, a 600V tube, if the voltage at both ends exceeds 600V, less than 0.1 seconds will explode; two fears overcurrent, a rated current 50A tube, if the current through more than 50A, It will explode in less than 0.2 seconds. For fear of overheating, IGBT can save 150 degrees or 175 degrees of temperature. Generally, it is controlled below 120 degrees. Heat dissipation design is one of the key technologies of inverter.
The damage of power devices means that the inverter needs to be replaced by the whole machine. But do not worry too much, because the inverter design, these factors have been taken into account, in normal circumstances, service life to 20 years is no problem. When the inverter is installed, it should be considered to leave a cooling channel for the inverter. In addition, if the grid has too high harmonics and too frequent voltage mutations, it will also cause power device overvoltage damage.
Two. Electrolytic capacitor
Capacitance is a component of energy storage, and is also an essential component of inverter.
Capacitors have electrolytic capacitors and thin film capacitors, each of which has characteristics and are required by inverters. There are many reasons affecting the life of electrolytic capacitors, such as overvoltage, harmonic current, high temperature, rapid charge and discharge, etc. Under normal use, the greatest impact is temperature, because the higher the temperature, the faster the loss of electrolyte volatilization. It should be noted that the temperature here does not refer to the environment or surface temperature, but the working temperature of aluminum foil. Manufacturers usually mark capacitor life and test temperature on the capacitor body. Volatilization of electrolyte limits the life of electrolytic capacitor. NCC capacitor in Japan is one of the best capacitors in the world. It has a maximum life of 15 years on the specification.
Three, LCD panel
The LCD display of the inverter can display the instantaneous power, power generation, input voltage and other indicators of the photovoltaic power plant. If you can show the cause of the trouble, it will be a good component.
Most inverters have monitors, but they do not. In addition to the above advantages, liquid crystal display has a fatal flaw short life. The general quality LCD monitors work for 3-4 hours, and it will be severely weakened and can not be used. According to the inverters operating time of 6:00-20:00 calculation, liquid crystal display work 14 hours a day, a year for 5000 hours. Suppose the life of the LCD is 40 thousand hours, the life of the LCD is 8 years.
Nowadays, the display is generally reserved in the household inverters, and the middle and high power series inverters used in power plants, without liquid crystal display screen is the trend.
There are two ways to dissipate heat in series inverter, forced air cooling and natural cooling.
Comparing the cooling capacity of series inverter, it is found that the cooling effect of forced air cooling is better than that of natural cooling. The forced air cooling can reduce the temperature rise of the key components such as capacitor and IGBT by about 20 C, which can ensure the long life and high efficiency of the inverter. The service life of high quality fans is about 40,000 hours. Intelligent heat dissipation inverters usually start to work only when the inverter power is above 30%. The average working time is about 4-5 hours per day, about 1,800 hours per year. It is no problem to use them for 20 years.
The most common fault of the fan is that the power supply of the fan is bad, or some foreign matter enters the fan interior, hindering the fan rotation.
The most common is the above mentioned power generation of the original, but also does not rule out the quality of the inverter itself, so we must check the quality of the inverter when installing, this is very important!