1. The pv inverter requires high efficiency. Due to the high price of solar cells in 2011, it is necessary to improve the efficiency of the inverter in order to maximize the efficiency of solar cells and improve system efficiency.
2. The pv inverter requires high reliability. 2012, photovoltaic power generation system is mainly used in remote areas, many power plants unattended and maintenance, which requires the inverter has the reasonable structure of circuit, strict screening of electronic components, instruments and demanded that the inverter for various protective functions, such as the input dc polarity reverse protection, ac output short circuit protection, overheating protection, overload protection, etc.
3. Pv inverter dc input voltage has wide adaptation range, as a result of the solar battery terminal voltage with load and sunshine intensity, although battery voltage plays an important role on the solar battery, but because of the battery voltage fluctuates according to the battery residual capacity and the change of the internal resistance, especially when the voltage of battery aging change range is very large, such as the 12 v battery, its voltage may change between 10 v ~ 16 v, which requires the inverter dc input voltage must be in a larger range to ensure the normal work, and ensure the stability of the ac output voltage.
4. In the photovoltaic power generation system with large capacity, the output of the inverter should be the sine wave with less distortion. This is because in the medium and large capacity system, with a square wave power supply, the output will contain more harmonic component and high harmonic will generate additional loss, many of the photovoltaic power generation system load for communication or instrument equipment, these devices have higher request for power quality, and large capacity of parallel operation of photovoltaic power generation system, in order to avoid pollution and public power grid electricity, also calls for sine wave inverter output current.