Study On The Coordinate Control Strategy Of Wind-Solar-Storage Microgrid

Distributed generation (DG) can address the high cost, maintenance, poor flexibilityissues of integrated grid, thus becoming a more and more studied form of power generationin recent years. However, there are some problems of its own, such as affecting powerquality, protection relays, and distribution network reliability, which, to a large extent,limits its effectiveness. In order to address these issues and inspire the potential ofdistributed generation, micro-grid concept has emerged, and soon became one of the latesttopics at the forefront of the field of electrical engineering research at home and abroad.Actually, the micro-grid control strategy directly determines the stability and reliability ofa micro-grid.This paper mainly studies the micro-grid integrated and coordinated control strategies,and, by theoretically analyzing, simulation platform construction, and simulation resultsanalyzing, laid the foundations for subsequent in-depth study of micro-grid.In this paper, a PQ controller, a V/f controller based on droop characteristic and theinverter output filter has been designed. Meanwhile, considering PI controller’sinsufficiency, the Model Predictive Control strategy was used to design the converter’s PQmodel predictive control strategy and V/f model predictive control strategy based on droopcharacteristics, and the simulation model was established in MATLAB/Simulink. Then, bysimulating a single micro-source respectively using PI controller and MPC controller indifferent scenes and by afterward analyzing and comparing, the effectiveness of MPCcontrollers was proved.After single micro-source’s integrating strategy research, the model of micro-gridwith multiple micro-sources was built, and through the simulating and analyzing under3conditions: the micro-grid operation mode switching, cutting or adding load in island mode,cutting a micro-source in island mode, it is found that the micro-source MPC controllerdesigned in this thesis achieved a sound power control behavior under the aforementionedthree conditions. Meanwhile, both the micro-grid’s voltage and frequency were within therequired range of the system, which proves the effectiveness of control strategies. Last, the wind-solar-storage micro-grid model was built, which used a wind powergeneration system, a photovoltaic cell and a storage battery to replace DC voltage sources,along with the design of corresponding control strategies. The whole model of the systemwas then built in MATLAB/Simulink, in which a storage battery was placed respectively inthe outlet of wind power generation system and the export of PV array column, forstabilizing grid power and offer voltage and frequency support in island mode. Thesimulation results validated the feasibility of the control strategies.