A newer means of optimizing the efficiency and reliability of solar systems is to connect microinverters (Micro Inverter) to each solar module. Equipping each solar cell with a separate microinverter allows the system to adapt to changing load and weather conditions, thus providing optimal conversion efficiency for both the individual solar cells and the system as a whole. PV systems with microinverter architecture simplify wiring, which translates into lower installation costs and increased efficiency of the solar power system, resulting in a shorter time to pay back the initial investment at .

Common grid-connected PV power system architectures include centralized, string, multistrand and AC modular schemes. In centralized, string and multistrand systems, there are series and parallel connections of PV modules, so the system targets the entire string/parallel PV arrays when tracking the maximum power point, and cannot take into account each PV array in the system. This results in low utilization of individual PV arrays, poor system resistance to local shadowing, and lack of flexibility in system expansion.

(1) The input voltage of the inverter is low and the output voltage is high. Since the output voltage range of a single PV module is generally 20 to 50V, and the peak voltage of the grid is about 311V (220V AC) or 156V (110VAC), the peak output voltage of the microinverter is much higher than the input voltage, which requires the microinverter to adopt an inverter topology with a step-up conversion function; while the traditional centralized inverter is generally a step-down converter, which The peak voltage on the AC side of the inverter output is lower than the input DC side voltage.

(2) Small power. The power of a single photovoltaic cell module is generally 100-300W, micro-inverter can be directly matched with a single photovoltaic cell module, and its power level is 100-300W, while the traditional centralized inverter power through the combination of multiple photovoltaic cell modules in series and parallel to produce a high enough power, and its power level is generally above 1kW.

(1) High conversion efficiency. The conversion efficiency of the grid-connected inverter directly affects the efficiency of the whole power generation system. In order to ensure the high power generation efficiency of the whole system, the grid-connected micro-inverter is required to have a high conversion efficiency.

(2) High reliability. Since the micro-inverter is directly integrated with the PV module, it is usually placed outdoors together with the PV module, and its working environment is harsh, which requires the micro-inverter to have high reliability.

(3) Long life span. The life span of PV modules is generally 20 years, and the life span of micro-inverter should be comparable to that of PV modules.

(4) Small size. The smaller the size, the easier it is to integrate the microinverter with the PV module.

(5) Low cost. Low cost is the inevitable trend of product development and the demand of micro-inverter marketization.