"Micro" is relative to the traditional centralized inverter. The traditional photovoltaic inverter is to combine all the DC generated by photovoltaic cells under sunlight in series and parallel, and then convert DC into AC through an inverter to access the power grid; Microinverters invert each component. Its advantage is that each component can be independently controlled by MPPT, which can greatly improve the overall efficiency, and can also avoid the DC high voltage, low light effect, and barrel effect of centralized inverters.
Product characteristics of Micro Inverter
1.The first is security; Traditional centralized inverters or series inverters usually have a DC voltage of hundreds of volts to thousands of volts, which is easy to catch fire, and it is not easy to extinguish after a fire. Micro inverse only tens of volts of DC voltage, all parallel, to minimize safety risks.
2.Then there is intelligence; Component-level monitoring to see the operating status of each component in the ECU.
3.More power generation; Component-level MPPT, no barrel effect, reduce the impact of shielding on power generation; Low light effect is good, because the starting voltage is low, only 20V, and it can work when the light is weak.
4.Service life; Usually the design life of the micro inverse is 25 years, and the traditional inverter is 10 years.
5.In appearance; There is no need to build a special power distribution room, and the micro-inverse can be directly installed behind the component or on the bracket, because it is a parallel structure, and the scale can be directly installed in the later period without changing the previous configuration.
Design requirements for Micro Inverters
The DC power conversion of Micro Inverters is AC from a single solar module, and each solar cell module is equipped with inverter and converter functions, and each component can convert current separately, so this is called "Micro Inverter".
The design of Micro Inverter we should focus on the following aspects.
1) Power density: The Micro Inverter requires a high power density, and the overall circuit should have a small volume.
2) Conversion efficiency: Because the current energy conversion efficiency of photovoltaic cells is not high, every 1% increase in the efficiency of photovoltaic grid-connected equipment can bring great economic value.
3) Reliability: The average first time to failure (MTFF) of centralized grid-connected inverters is usually 5 years, and the average time to failure (MTBF) is about 10 years. The life of photovoltaic cells is more than 20 years, so the life design index of micro-inverters must be equivalent to that of photovoltaic cells in order to reflect the advantages of the program. Its MTBF should be greater than 20 years, and the MTFF should be more than 10 years.
4) Cost: The AC module system is configured with micro-inverters for each photovoltaic panel, which requires that the cost of micro-inverters is low and fewer devices should be included in the circuit. Its controller can handle all control, communication and computing tasks, and must have a low price.
