The Research Of Power Fluctuation Smoothing And The Development Of D-STATCOM/BESS

In recent years,the problems of world's energy structure and environmental are becoming more and more serious,new energy sources has become a new direction for people to study,solar energy is widely used because of its universality,infinity,economy and non pollution.Nowadays,photovoltaic power generation industry is not only as a supplement to energy,but the main source of energy in the future in the world.However,as the main energy sources of solar energy photovoltaic micro network has the intermittent,random and other issues which prone to power fluctuations,resulting in abnormal operation or damaged of load.By adding power compensation equipment to photovoltaic micro grid is a great way to ease power fluctuations in the micro grid,ensure micro grid operation stability and safety and the normal work of the load.This paper regard power fluctuations as the research object,based on the research of the D-STATCOM/BESS and the characteristics of active power and reactive power can be compensated simultaneously,improve the coordination control strategy of compound power,considering the influence of the output power of the photovoltaic cells,makes it more suitable for the working characteristics of photovoltaic micro grid,give full play to the advantages of D-STATCOM/BESS in terms of power bidirectional flow.The specific work of this paper is divided into three parts.Firstly,in view of the power quality problems,especially the power fluctuation,study on the static var compensation device and the energy storage device,found when they are used in a separate there is obviously insufficient,can not conform to the requirements of the project.In order to make up for the disadvantages of the two device,D-STATCOM and energy storage devices are combined as D-STATCOM/BESS which can compensate active power and reactive power simultaneously.To ensure the stability of PV micro-grid system and the normal operation and safety of sensitive load equipment in micro grid system.Secondly,study on the mathematical model of D-STATCOM/BESS deeply and the control strategy which based on the mathematical model.Due to the complex environment of PV micro grid,solar energy as the main energy source,so the research on the control of the output power of photovoltaic cells is particularly important.By comparing the various maximum power point tracking(MPPT)algorithms,Perturbation and Observe algorithm for maximum power tracking were selected.But the algorithms have many problems like power fluctuations in the MPP point.Considering the characteristic of photovoltaic battery and the shortcomings of the algorithm,this paper puts forward the asymmetric variable step Perturbation and Observe method.In order to better compensate the power fluctuation in the PV micro grid,and based on the current feedforward decoupling control method,this paper presents a hybrid power coordinated control strategy for photovoltaic micro grid which consider MPPT,SOC of battery,rated current.Thirdly,according to the design goal of the project,the D-STATCOM/BESS model of MATLAB/Simulink is established,and the physical prototype is built in the laboratory.The power compensation effect of DSTATCOM/BESS is tested on the platform,the experimental results show that the compensation device can realize the bidirectional flow of energy with the PV micro grid.,smooth power fluctuation in micro grid,ensure stable operation and safety of micro grid.