Research On Hierarchical Coordinated Control Strategy Of AC/DC Hybrid Microgrid

Microgrid provides an effective technical approach for the large-scale application of distributed generation,and is also an important means to achieve high-efficiency,environmental protection and high-quality power supply in the future.It has broad application and development prospects.As a special form of microgrid,AC/DC hybrid microgrid can effectively integrate the advantages of AC microgrid and DC microgrid and flexibly consider the different power consumption modes of AC load and DC load,effectively reducing the energy loss of multi-level conversion,Improve the flexibility of the power supply system for optimal operation and control of the level.With the increase of the types of distributed power supplies and the increase of the number of DC load,the structure of AC/DC hybrid microgrid tends to be complex and diverse.The diversification of AC and DC power supply modes,the strong randomness of wind power and photovoltaic power supply,greatly increase the difficulty of coordinated control of AC/DC hybrid microgrids,and various types of coordinated control strategies can not meet the complicated topology.The refore,it is of great value to study the coordinated control of the typical topologies of AC/DC hybrid microgrids to further explore the application of AC/DC hybrid microgrids.This article focuses on AC/DC hybrid microgrid hierarchical control operation to start research.First of all,the research background and significance of this subject are introduced,and the development of microgrid at home and abroad and the research status of AC/DC hybrid microgrid control technology are summarized.Secondly,the topology and hierarchical control architecture of AC/DC hybrid microgrid,analyzes the voltage and frequency preliminarily of equipment level control and power sharing and voltage frequency recovery of system level control,and summarizes the control theory and control characteristics of hierarchical control architecture.Thirdly,the topology structure of typical AC/DC hybrid micro-grid and coordinated control system,the mathematical modeling of photovoltaic array,energy storage battery and converter is established.Local control of each unit based on local information and control switching unde r different operating modes are respectively designed.Finally,the energy management and coordinated control of AC/DC hybrid grid-connected and off-grid mode are put forward.The power balance and the coordinated control of each grid based on different charged states of storage battery under different operating conditions are analyzed.And build a model in Matlab / Simulink to simulate a variety of conditions.Simulation results verify the correctness and reliability of this strategy and achieve device-level control of AC/DC hybrid microgrid voltage stability and system-level power distribution,bus voltage secondary coordination and multi-mode operation.