Cooperative Control For Distributed Photovoltaic Grid-connected Power Generation Systems

The increasing depletion of traditional energy sources and the gradual deterioration of the global environment have prompted the pursuing of low-carbon and the development and utilization of new energies. Clean solar energy with the advantages of sustainable development has attracted the world’s attention. Solar energy has abundant resources and no geographical restrictions. It rarely produces contamination or never pollutes the environment. Many countries promulgate new energy laws. And these new laws have played an important role in developing solar energy. The photovoltaic power generation has profound theoretical and practical significance. In the past few years, the total installed photovoltaic power plant has reached trillions of kilowatts. Especially the distributed grid-connected PV power generation systems attract the unprecedented attention, and it is the key how to make more efficient coordination of distributed power generation systems.Firstly, this dissertation introduces the background and significance of photovoltaic power generation, analyzes the current situation of photovoltaic power generation at home and abroad, and introduces the control modes of distributed generation. Secondly, the equivalent model of the single-phase photovoltaic system is analyzed comprehensively. Next, this dissertation proposes a two-level distributed control strategy, that is, cooperative control based on dynamic matrix control. The upper level is cooperative control, and the lower level is dynamic matrix control. This control strategy not only makes the distributed PV units converge and operate at the same ratio of the available power, but also regulates the total power output of all the PV units to ensure the stability of the distributed power generation systems. Then it introduces the theory of cooperative control and dynamic matrix control algorithm, and designs the corresponding controllers.Finally, the simulation platform of distributed grid-connected photovoltaic power generation system with multiple photovoltaic units is built through Matlab/Simulink. Simulation results of the system applying the proposed two-level control strategy and the system applying one-level control strategy without cooperative control are compared. This analyzes their slightly superior, verifies the effectiveness of the proposed control strategy.