Research On Active Power Balance Control Strategy Of Modular Hybrid Microgrid

As an important part of smart grids,microgrid can effectively promote the consumption of new energy sources,improve the development of low-carbon economy and improve the flexibility and reliability of power system.However,due to the lack of configuration standards and construction models,most of microgrid projects adopt customized design schemes,making it difficult to be widely promoted and mass-applied in the distribution network.Facing modular hybrid microgrid,the active balance control mode is discussed and the active power balance control strategy of modular hybrid microgrid is studied.In this thesis,aiming at the characteristics of its multi-regional division,users are modularized and integrated to form an independent and single controlled unit with specific functions.Firstly,according to the types and characteristics of regional distributed power,the basic functional modules are divided into balanced modules,controllable power modules and uncontrollable power modules.The structural composition,control tasks and control method of micro-power grid-connected converters in various functional modules are studied in depth.In order to meet the dispatch ability of the microgrid connected to the 10 kV voltage level,the active power adjustment range of modules is defined.In addition,the compensation method of active exchange power’s difference is studied,allocated the difference of the active exchange power between the microgrid and the distribution network to the module with adjustment capability.Thus,the controllable switching power operation mode of the AC/DC hybrid microgrid is realized.Secondly,in order to meet the requirements of hybrid microgrid operating under modular structure,a three-layer hierarchical control architecture including microgrid layer,module layer and user layer is designed in this thesis.The control functions and information interaction method between different control layers are determined.On this basis,an active hierarchical control strategy in modular hybrid microgrid is proposed.Finally,based on the IEEE-33 test system where some of the nodes are transformed into a modular AC/DC hybrid microgrid,the corresponding simulation models on the simulation platform is built.The steady-state operation and control operation simulation verification are carried out.The simulation results show that the hierarchical control can meet the operation requirements of modular hybrid microgrid,the frequency and voltage of the microgrid are stable and the following characteristics of microgrid to the distribution network dispatchinstruction is well.Further,the correctness and effectiveness of the regulation strategy proposed in this thesis are verified.