Design of a GaN-Based DC-DC Converter with HiLEM Topology for Efficient MPP-Tracking

The rapid expansion of solar energy generation is increasing the importance of efficiency in large-scale Photo-voltaic (PV) systems, especially under non-optimal conditions such as shading, soiling, ageing, defects or asymmetric string configuration. For this reason, multi Maximum Power Point Tracking (multi-MPPT) at string level is becoming more and more important to increase the yield per area. The single Maximum Power Point Tracking (single-MPPT) in a central inverter, which is common in large scale PV systems, has significant disadvantages under difficult operating conditions. Therefore, this paper presents the hardware design of a Gallium Nitride (GaN)-based DC-to-DC converter (DC-DC converter) with the High Efficiency Low Effort MPPT (HiLEM) topology as a Partial Power Converter (PPC) for a string-based multi-MPPT. Measurements of a hardware prototype show the general functionality of the used topology. Finally, the losses of the power semiconductors of an conventional multi-MPPT topology are compared with those of the HiLEM topology.