Feed-in Tariff system was started from July 2012 in Japan. According to the act, the electricity energy generated from large-scale Potovoltaic (LSPV) generating stations is bought for 42 yen per kWh including tax for 20 years. This price is about 3 times as large as a normal electricity rate. However it is still important to improve efficiency of the LSPV system in order to return high investment as soon as possible. The New Energy and Industrial Technology Development Organization (NEDO) advertised for consignment research business called "Verification of Grid Stabilization with Large-scale Photovoltaic Power Generation Systems" in 2006. 2MW PV system was constructed for this research in Hokuto City and five-year tests were finished in 2011. In the research, we clarified a MPPT control method for large-scale power conditioning systems (LS-PCS) to get more PV energy efficiently. Results were confirmed by ATP (Alternative Transients Program) simulations and also the field. The verification test results of grid stabilization systems by the developed LS-PCS and PV systems were also described and discussed.