Research On Stability Control Strategy Of Photovoltaic DC Microgrid

At present,the world energy pattern is deeply adjusted,a new round of energy revolution is booming.For the power industry,power station and the user side is evolving.China is one of the countries that are rich in solar energy resources.The distributed photovoltaic power generation has entered into the practical application stage in recent years.On the user side,with the increase of DC load,such as electric vehicles,DC microgrid technology has become a research hotspot.The combination of photovoltaic PV system will become one of the main power supply structure.In this paper,the two problems in the operation of the system are studied: the maximum power point tracking(Maximum Power Point,MPPT)and the stability control strategy of the system is studied in this paper.The development of photovoltaic DC micro grid tends to be miniaturization and household operation,which is one of the main power supply structure of city in the future.Because of the complex environment in the city,photovoltaic cells are often shadowed,and the array P-U characteristic curve is multi peak,and the traditional MPPT strategy may fail.Therefore,the two step method of photovoltaic array MPPT strategy is the photovoltaic prediction + the actual MPPT.The first step is to build a model of horizontal polishing cell(small amount of calculation),and MPPT uses the particle swarm optimization algorithm with filter domain to obtain the approximate maximum power point of the photovoltaic cell.The second step: MPPT uses the perturbation observation method,and obtains the actual maximum power point position by simple perturbation at the approximate maximum power point.Therefore,this method can effectively solve the problem of photovoltaic power generation MPPT under shadow conditions.The structure of photovoltaic DC microgrid system can be seen as the DC bus connecting the system by various modules such as photovoltaic micro source,energy storage battery,etc..In the process of operation,the change of DC bus voltage is very important to the stability of the system.The traditional converter control strategy,such as droop control,can solve this problem.Therefore,according to the development process of the system control strategy,put forward the dynamic thecoefficient AC microgrid based on droop control strategy and its application to DC system,combined with the proposed DC micro grid adaptive control strategy,adaptive dynamic coefficient droop control strategy based on the new.The traditional control strategy compared to the control strategy,reduce the voltage fluctuation caused by the changes of power system operation module for change,astaticmodulation implementation of bus voltage in the system,improve the stability of PV DC microgrid.Finally,through the MATLAB to build a single busbar photovoltaic DC microgrid system,analyzes the impact of strategy on system stability and improvement of the traditional control strategy is applied,and then the experiment verifies the effectiveness of the improved control strategy.Since then,to a certain extent,solve the photovoltaic DC microgrid system running the two major problems.