As the depletion of fossil fuel is accelerating and resource-rich nations are using their energy resources as a bargaining chip in the international politics increasingly in the 21st century, development and distribution of energy-dfficient solution is carrying more signigicance and the need for substitutes fo conventional fossil fuel is rising more than ever. In addition, as goverments are tightening their regulaion around the world on environmental pollution resulting from the use of fossil fuel, new and renewable energy development programs are actively underway in many countries to draw on solar energy which is a source of vitrually limitless energy and many industrializd nations are planning to meet more than 10% of their total energy demands with new and renewable energy.

Photoboltaic system is a distributed electricity generation system. It started off first as a stand-alone generation system applicable mostly to islands of remote places where access to national power grid would be too costly to porvide. However, photovoltaic solutions are being integrated rapidly with national power transmission network these days. Against the backdrop, grid-connectd photovoltaic inverter that ensures stable conversion of DC power for AC power transmission network and minimizes potential impact on national power grid are in great demand.