The typical PV module produce DC power output and connected to the junction box and inverters to produce AC power output. However through use of Microinverters are the small systems replacing the existiing junction box of the PV module and will provide AC power coming out directly from the PV module. The biggest advantages of micro-inverters are in the small installations below 10KW. In traditional rooftop systems there is partial shading, there is dust, which leads to less power output from one of the module connected in the series. The overall power output of the string is dictated by the weekest module in the series facing dust or shading. For example a module of 200 W will produce only 50 W of power and will affect the power output of all the modules connected in series and will reduce the overall system output by 30%. In case of microinverters connected on each module as a string inverter this problem is not faced and individuel module power of the weekest module in the system does not affect the power output of the other modules. This leads to an overall gain of almost 20-30% extra energy from the installed system, which is the biggest advantage of micro-inverter systems.
There are some secondary benefits of micro-inverters, one of them is that in the traditional string inverters you have high-voltage DC distribution. That is a safe voltage, but there are concerns from the home user, they don’t want to see high-voltage going on their roofs. And they would prefer traditional AC voltage, they are more comfortable that this is going on their roofs. Then other advantages are in terms of the installation costs, with the integrated AC model panel, you can considerably reduce the installation cost. So these are some of the advantages of micro-inverter technologies.
It is god to use the micro-inverters for the 10KW and under market, and one can expect overall additional energy gain of about 5%.
Dr. Praveen Jain, the CEO of Sparq Systems Inc., has recently developed this inverter and he expects that in future the micro-inverters will replace the centralized inverters or the string inverters in the grid connected solar farms as well.