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Research On Isolated Multi-Microgrid Voltage Control Method Based On Improved LQR And MPC

Posted on:2019-03-09Degree:MasterType:Thesis
Country:ChinaCandidate:T B TangFull Text:PDF
GTID:2322330542957685Subject:Control Science and Engineering
Abstract/Summary:PDF Full Text Request
In response to the global energy crisis and the increasingly serious environmental pollution problems,distributed renewable energy sources have been rapidly developed,but their large-scale access has impacted the power grid,seriously affecting the reliability of power supply and the quality of electrical energy services.Microgrid technology was born.As a beneficial supplement to the large-scale power grid,the micro-grid is an effective way to realize the large-scale utilization of distributed power,and as an important component of the smart grid,it is of great significance for the promotion of new energy,energy conservation and consumption reduction of power production,and reduction of carbon emissions.On this basis,the research and development of multi-microgrid technology has important research and practical significance for realizing the mutual energy of microgrid and enhancing the reliability of power supply.Based on the research in the field of coordinated control of multimicrogrid in the current stage,this paper aims at the voltage control of point-ofcommon coupling(PCC)in isolated multi-grid power grids,and studies the modeling of the multi-microgrid system,the state estimation,the application of the control strategy and the simulation analysis.The main research content is as follows:Firstly,on the basis of summarizing the research status at home and abroad for multi-microgrid,the problems in the current research of multi-microgrid are pointed out.Based on the study of the hierarchical control mode and operation control strategy of multi-microgrid,a hierarchical control structure of multi-microgrid with distributed power supply and PCC voltage control state space model was established,and the state estimation of the discretized state space model was obtained.Relatively accurate status information provides the basis for the application of multi-microgrid control strategies.Secondly,aiming at the problem of PCC voltage control in multi-microgrid system,an improved linear quadratic regulator(LQR)method based on genetic algorithm is proposed.Using MATLAB to verify the proposed control method,the results show that this method can effectively control the PCC voltage fluctuation within the specified range.In addition,the simulation analysis of the system under load removal and communication faults,the results verify the correctness and effectiveness of the proposed control method.Finally,a constrained Model Predictive Control(MPC)method is proposed.Taking into account the different types of distributed power supply output characteristics,impose different constraints on the state space model of the multi-microgrid,convert the constraint optimization problem into a QP(quadratic programming,QP)problem,and use the MPC method to achieve rolling optimization of the PCC voltage Stable control,and achieve the internal energy of the micro-grid and improve power supply reliability.In addition,a simulation comparison of the constrained MPC method and the improved LQR method based on the genetic algorithm yields its advantages and disadvantages.
Keywords/Search Tags:multi-microgrid, voltage control, LQR, model predictive controll
PDF Full Text Request
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