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Study On The Cooperative Control Strategy Of Power Stabilization And Reactive Power Compensation Of The STATCOM/BESS In Photovoltaic Microgrid

Posted on:2019-07-23Degree:MasterType:Thesis
Country:ChinaCandidate:Y J WuFull Text:PDF
GTID:2382330545991312Subject:Control Science and Engineering
Abstract/Summary:PDF Full Text Request
In order to break through the energy crisis and environmental crisis,promote the development of energy saving,emission reduction and low carbon electricity,the new energy generation power generation,such as solar energy and wind energy,has sprung up after the rain.In order to give full play to the role and benefits of distributed generation,microgrid emerges as the times require,and photovoltaic microgrid develops most rapidly.However,the randomness and volatility of PV generation seriously affect the operation efficiency and security stability of PV grid system.In this paper,the power compensator with energy storage in the photovoltaic microgrid is used to regulate the power of the microgrid effectively,and at the same time,when the microgrid is connected to the power grid,it plays a role of stabilizing the voltage.The STATCOM with battery energy storage system(short for STATCOM/BESS)in the photovoltaic microgrid has the function of fast reactive power compensation of STATCOM and the active regulation function of storage battery system,which plays the role of suppressing the power and maintaining the normal and stable operation of the whole microgrid.This paper takes the STATCOM/BESS system in the photovoltaic microgrid as the research object.Through the analysis of the working principle and mathematical model of the STATCOM/BESS,to better play the active and reactive power and reactive power of the STATCOM/BESS system,the control algorithm is the main research content,and the control of the STATCOM/BESS is improved.The main contents of this paper are as follows:First,the principle and mathematical model of the STATCOM/BESS four quadrant power regulation of the storage battery into STATCOM by the DC/DC converter are analyzed.The switch function model,the small signal model and the large signal model are derived.The current closed loop control on the DC converter and the voltage and current double closed loop power feed-forward control on the STATCOM side are realized,and the control process of direct power control is briefly analyzed.Secondly,the direct power balance control algorithm of multiple battery banks connected to DC side in STATCOM/BESS is studied.As the traditional constant proportion constant control strategy is applied,the power balancing speed will decrease with the gradual increase of battery state of each battery.Therefore,based on the charge state value of the battery group,a power balance control algorithm with variable proportion constant is proposed.By changing the size of the equilibrium constant,the power balance adjustment can be completed faster on the basis of having no effect of the total power regulation,and the calculation rules of the equilibrium constant value are given.Thirdly,the power direct control under the traditional power prediction is the constant frequency control of the reactive power zero of the STATCOM/BESS system under the fixed frequency of the switch tube,because the control of the reactive power is insufficient,and the error of the reference power prediction algorithm is large.In this paper,the expression of AC voltage measurement is re-derived on the basis of reactive power,and the two-order Lagrange interpolation algorithm is used instead of the traditional linear interpolation to predict the power of the reference.The simulation results show that the improved algorithm has a better power adjustment and the stability of the DC side voltage.Finally,in order to give full play to the four quadrant power regulation capability of the STATCOM/BESS device,based on the charge state of the energy storage battery system,the active power and reactive power needed to be consumed by the output power of the photovoltaic cell array and the load in the microgrid system are taken into consideration.A kind of power cooperative control algorithm is proposed,which is through the random fluctuation of light intensity and the voltage disturbance during the grid connection.In the two cases,simulation and comparative analysis verify the effectiveness of the proposed power synergistic control algorithm.
Keywords/Search Tags:Microgrid, STATCOM/BESS, Power equilibrium, Power regulation, Synergistic control
PDF Full Text Request
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