Modeling and Nonlinear Dynamic Analysis of a Photovoltaic System With Multiple Parallel Branches Based on Simplified Discrete Time Model

The widely used dc distribution system mainly based on new energy generation consists of multiple power electronic converters in series and parallel. The mutual coupling among these converters can lead to complex nonlinear behavior. It is necessary to build a more accurate mathematical model for identifying a more comprehensive nonlinear behavior of this kind of high-order complex system. Therefore, a double-branch parallel photovoltaic system is taken as the research object in this article, where we carry out accurate modeling and nonlinear dynamic analysis of the system. First, the influence of environmental factors on the output characteristic of the system is considered when modeling the photovoltaic generator. Second, the simplified discrete-time model is introduced in the dynamic model, which not only simplifies the calculation process but also ensures the accuracy of the calculation results, and is suitable for systems with different switching frequencies. Subsequently, the nonlinear behaviors of the system are analyzed in detail by using the constructed model, and the Hopf bifurcations are identified. Through the simulation comparison, the significant advantage in the calculation accuracy of the modeling results is verified. Finally, the effectiveness of the theoretical analysis is further demonstrated through experimental verification.