PV modules capacity and inverter capacity ratio called capacity ratio. Reasonable capacity design need to be combined with the specific project situation. The main effective factors including irradiance, system loss, inverter efficiency, inverter life, inverter voltage range, modules installation angle and so on.
1. Different areas of different irradiance
Different regions have different solar illumination. Even in the same resource area, there is a big difference between different parts of the annual radiation
2. System loss
In PV system, the energy from the solar radiation to the PV module, through the DC cable, confluence box, DC power distribution to reach the inverter, which has lost all aspects of the link.The DC side loss is usually about 7-11%, the inverter loss of about 1-2%, the total loss of about 8-13%. The system loss does not include the inverter behind the transformer and Line loss part.
In other words, in the case where the capacity of the module and the inverter capacity are equal, the actual output maximum capacity of the inverter is only about 90% of the rated capacity of the inverter, even when the light is the best , The inverter is not fully loaded.
3. Inverter efficiency
The efficiency of the inverter is not constant value, there are power switching device loss and magnetic loss. The efficiency is relatively low if power is low. The highest efficiency is 40%-60%. The efficiency gradually reduced when over 60%.
Therefore, the total power of the PV power is controlled between 40% and 60%, the inverter power to achieve optimum efficiency.
4. The lifetime of the inverter
PV inverter is an electronic product. It has a great relationship with reliability and inverter operating temperature. If capacitors, fans, relays and other components temperature increased by 10 ℃, the failure rate can be increased by more than 50%. While the operating temperature is related to power.
According to statistics, the lifetime of inverter long-term work in the power 80-100% lower than40-60%.
5. The optimum operating voltage range of the inverter
The operating voltage is rated at the highest rated operating voltage of the inverter.
Single phase 220V inverter, the input rated voltage is 360V, three phase 380V inverter, the input rated voltage is 650V.
260W solar panel modules, operating voltage is 30.5V, if equipped with 3kW inverter, using 12 working voltage 366V, it is best that 3.12KW total power.
If equipped with 30kW inverter, 126sets solar panel modules, each 21 string, the voltage is 640.5V, it is best that 32.76KW total power.
Anhui JNGE POWER Co.,LTD as a professional DC to AC pure sine wave inverter manufacturer in China,can provide you high frequency inverter,Low frequency pure sine wave inverter and other products.
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