AC Module system
The PV system consists of two main parts, the PV module and the power electronics which converts the DC power produced by the modules in to AC power (Inverter). In case of the grid tied PV system there is no energy storage requirement, however the off grid systems at times use the energy storate systems which can provide a reliable power at times when there is no sunshine.
PV modules are connected in to a series/parallel combination in strings and and deliver power to the centralised inverter system. The mismatch in the individual power output affects the whole array output and the power output of the whole array is dectated by the weekest module in the string. This reduces the overall performance of the PV system in terms of energy yeild.
In order to overcome this problem many people have tried through the multi multi-string PV system. In this case, each PV-string is assigned a DC/DC converter and all of them are connected in parallel to one inverter. Also here each string has a MPPT and can be controlled individually. The inverter in this case has a higher power level like in centralized case with higher efficiency. Yet, in both approaches, there is still some MPPT mismatch between the modules of one PV string. Consequently, not all available energy from the sun can be captured by the installed PV system. Hence, the AC-Module PV system becomes the most efficient approach that guarantees 100% harvesting of the available power.
The AC-module PV system has a DC/AC converter is attached to each PV panel. It is believed that this approach will be the trend for the future PV industry. In this type of PV system, the MPPT problem is completely solved since each PV module is connected to one inverter that has an MPPT. The AC-Module PV system offers Plug-N-Play concept. This option gives a high order of flexibility. This flexibility in the system makes it more common and easy to be used for end user application. Moreover, the modularity provided by the AC-Module PV system makes the future expansion of the whole system easier.