Light-load efficiency optimization for module integrated converters in photovoltaic systems

Efficient control strategies to optimize the light-load efficiency are necessary for module integrated converters (MICs) applied in photovoltaic (PV) systems. With no need for the additional current sensing, the MIC working in discontinuous conduction mode (DCM) automatically at light load can be achieved in this paper. Due to challenges in the efficiency optimization of the MIC and the trade-off between different losses in the MIC at light load, the maximum efficiency point tracking (MEPT) along with variable frequencies is proposed to further improve the light-load efficiency. With the proposed hybrid control strategies, the efficiency of a non-inverting Buck-Boost converter applied in PV systems can be greatly improved at light load. Furthermore, the proposed control strategies are analyzed in detail and verified with experimental results.