Research On Energy Management For PV Distributed Generation System With DC Bus

With the deepening of using new energy, photovoltaic (PV) distributed generationsystem with DC bus has become a new type of structure in using solar energy. And theenergy management of the entire system is a hot topic of the study.On the basis of reading a large number of related foreign and national literatures, thepaper researches on the structure of PV distributed generation system with DC bus. Theprinciple and the features of PV unit, battery unit and full cell unit are described in detail.At the same time, the power electronics converter interfaces including the bi-directionalDC/DC converters and three phase inverter are analyzed and simulated. This system iseasily extensible and flexible control. However, coordination between multiple energyunits and loads, improving the energy utilization and controlling the flow of energy are thecritical issues. So we should find the effective energy management strategy to control thesystem. In the understanding of the characteristics of each functional unit of the PVdistributed generation system with DC bus, the paper introduces the principles of energymanagement and proposes the centralized energy management strategy based on thepower balance equation. The paper does some simulation research of the system’soperating mode, the switching between the modes and the proposed energy managementmethod. Based on the operating characteristics of the bi-directional converter the paperdoes some research on the uncontrolled area when the power is equal, and draw thecorresponding conclusions.After the simulation analysis, the paper does some experiments including PV MPPT,running independently and grid-connected of the whole system through the digitalexperiment platform. The simulation and experimental results show the correctness andvalidity of the proposed energy management strategy and the system control method.