A Hybrid Controller for Novel Cascaded DC-DC Boost Converters in Residential DC Microgrids

This paper presents a performance analysis of a new cascaded boost converter for low voltage (LV) residential DC microgrid. Photovoltaic (PV) systems are getting high attention as a renewable energy resource for LV DC microgrid applications. Partial Shading (PS) is a serious issue in PV systems as it leads to a significant reduction in power generation. The conventional boost converter topology is usually employed to mitigate the mismatch issue between the PV arrays or modules caused by the PS problem. In some cases, the PV module is divided into three submodules (SMs) where a bypass diode is integrated with each SM to protect the PV module from the hot spot (HS) effect. The mismatch problem between the SMs inside a single PV module can result in a significant reduction in power generation caused by isolating the shaded SM from the PV system. However, isolating the SM from the PV system can mitigate the HS negative effect at the expense of losing the power of the shaded PV SM. This paper suggests a PV SM DC-DC cascaded boost converter to overcome the mismatch concern between the PV SM of a single PV module in the modern DC microgrid. It employed a Perturb and Observe (P&O) tracing algorithm with each PV SM to individually harvest the maximum available power. The study proposes an optimized operating strategy based on PV power generation, local demand, and battery state of charge (SOC) to enhance the reliability of the DC microgrid system.