Development of buck-boost maximum power point tracking for a solar cell using GaN semiconductor

Owing to the characteristics of solar cells used in photovoltaic (PV) systems, solar radiation fluctuations due to clouds, sun altitude, and obstacles in the installation environment lead to fluctuation in the generated power. At this point of time, variations in power generation may occur within the range of maximum power point tracking (MPPT) control. If the area with low power generation cannot be bypassed, the overall power generation is reduced. Thus, system operation with high efficiency is expected to be difficult. To cope with this problem, the authors developed a buck-boost MPPT that can be configured as a distributed MPPT. Furthermore, to improve efficiency, a GaN field-effect transistor (FET), rather than the conventional Si FET, was used. In this research, we showed that the MPPT using GaN semiconductors is more efficient than MPPT using Si semiconductors. In addition, it was found that when partial shadows were formed on the PV module, the distributed MPPT could exert higher power generation efficiency than the concentrated type.