Research On Power Quality Control Strategy Of Multi-function Grid-connected Inverter In Microgrid

With distributed power,power electronics,and non-linear loads are randomly and heavily accessed,the power quality pollution of microgrids is becoming more and more serious.Due to the high power quality are quirements of electrical equipment,and the weak ability of microgrid to absorb power quality pollution,the power quality problem of microgrid is particularly prominent.Multi-Function Grid-Connected Inverter(MFGCI)has many functions such as active grid connection,harmonic control and reactive power compensation.Therefore,from the perspective of power quality dispersion autonomy,this paper establishes MFGCI capacity allocation strategy and proposes power quality management optimization strategy.The proposed strategy has important practical significance for reducing power quality pollution,improving equipment utilization efficiency,and improving system operation economy.Firstly,this paper introduces the research significance and common governance methods of harmonic control and reactive power compensation,and explains the research status of MFGCI and the topological structure of MFGCI power quality management.Then the paper comprehensively analyzes the capacity relationship between harmonic optimization optimization variables and active grid-connected and reactive power compensation,and proposes the solution ideas of MFGCI harmonic current compensation and reactive power compensation,which provides a theoretical basis for MFGCI to achieve power quality control optimization.Secondly,combined with the requirements of harmonic pollution control of photovoltaic power generation system and the requirement of grid connection of photovoltaic maximum power,this paper proposes a harmonic control optimization model for photovoltaic power generation system.Considering the output characteristics of photovoltaic cells and the influence of harmonic compensation on the MFGCI capacity allocation,the harmonic control optimization model is established according to the situation.The simulated annealing particle swarm optimization algorithm is combined with the example to verify the proposed model.Finally,in view of the harmonic distortion and voltage deviation of the microgrid system,this paper considers the comprehensive benefits of microgrid operation and the economic benefits brought by power quality control.From the perspective of power optimization and power quality autonomy,it proposes active power optimization and node voltage deviation.A two-layer optimization model for power quality management of microgrids optimized by harmonic distortion management.Among them,the upper layer aims at the lowest operating cost of the system,and determines the active grid connection capacity of the distributed power source,thereby affecting the lower MFGCI power quality management capacity.The lower layer aims at the system node voltage deviation and the minimum harmonic distortion.The MFGCI harmonic control and reactive power compensation are determined,and the processed power quality parameters are fed back to the upper layer to change the economic operation cost,thus affecting the active grid connection.By studying the relationship between the upper and lower decision variables,this paper analyzes the influence of the upper and lower decision-making,and formulates the capacity coordination strategy of power quality governance and active grid-connected optimization process.Finally,the simulated annealing particle swarm optimization algorithm is combined with the example to verify and analyze the two-layer optimization model.