Research On Adaptive Control Of BFVC-ADRC AC/DC Hybrid Microgrid Considering SOC Of Energy Storage

AC-DC hybrid microgrid has more advantages than single AC or DC microgrid in power generation efficiency,energy utilization,system completeness and other aspects.However,due to the continuous access of various distributed power sources,the micro-grid system lacks inertial support,and the insufficient frequency and voltage stability and other problems become more and more serious.In order to solve this problem,many scholars at home and abroad make use of the characteristics of the fast and flexible control of energy storage system and micro-grid interconnecting converter to balance the bidirectional power between networks,which can reduce the loss of energy and enhance the dynamic stability of the micro-grid.Firstly,This paper introduces the research background and significance,briefly describes the research status of the control methods of energy storage and interconnecting converter in AC-DC hybrid microgrid at home and abroad,and then introduces the model structure and control strategy of hybrid piconet and micro-source.Secondly,a compensatory droop control strategy with multiple regions of frequency and bus voltage is studied for the energy storage at both AC and DC sides of microgrid.An improved droop coefficient with continuous and different changing trends was proposed to control the running state of energy storage by the order of bus voltage,battery voltage and SOC.Among them,the AC side energy storage is controlled by P-F droop control,and the reference active power is adjusted by setting frequency dead zone and frequency offset.The DC side energy storage is controlled by U-I droop control,the virtual resistance and voltage deviation are set to dynamically adjust the bus voltage,and its dynamic regulation ability is verified in the environment of MATLAB/Simulink.Thirdly,in order to solve the problem of unbalanced power flow and slow response of the conventional microgrid interconnecting converters in AC-DC hybrid microgrid,a normalized power outer loop and a secondorder active disturbance rejection controller are used to replace the inner current loop of traditional interconnected converters.Among them,the power outer loop adopts the double droop control based on the idea of system frequency and bus voltage normalization,which improves the response speed and anti-interference ability of the system.Finally,an AC-DC hybrid microgrid simulation model of wind power,photovoltaic power,energy storage and load are established in the MATLAB/Simulink to verify the effectiveness of the proposed strategy.The results show that the proposed strategy can not only ensure the stability of frequency and voltage,but also accelerate the response speed of the system and improve the dynamic performance of the hybrid microgrid when the distributed power supply output changes,load changes and unilateral energy storage cannot work.