Bifurcation Analysis and Experimental Study of a Multi-Operating-Mode Photovoltaic-Battery Hybrid Power System

Stand-alone hybrid renewable power generation systems have gained popularity in recent years. However, due to the intermittent nature of the renewable resources, hybrid renewable power generation systems are often designed to operate with multiple structures and multiple operating modes. The design for stable operation of such systems requires consideration of the stability conditions for all possible structures and operating modes. A stand-alone photovoltaic-battery hybrid power system is studied for illustrating the possible complex behavior in this paper. We reveal smooth bifurcation, including slow-scale Neimark-Sacker bifurcation, fast-scale period-doubling bifurcation as well as coexisting bifurcation. Under certain conditions, when the system switches its operating mode, a nonsmooth bifurcation, manifested as a jump between stable and unstable behavior, can also be observed. Moreover, a detailed analysis based on a discrete-time mapping model is performed to evaluate the stability boundaries of the system. Extensive experiments verify the analysis and simulated results.