Coordinated Control Of Island DC Microgrid Based On Bus Voltage Signal

With the rapid development of the national economy,the demand for electricity is increasing,the scale of the power grid is continuously expanding,and the drawbacks of the traditional large-scale power system are becoming increasingly prominent.The operation and maintenance is difficult and costly,and it is difficult to adapt to the safety,reliability and diversification of users power supply requirements.Therefore,the DC microgrid with DC bus as the energy interaction medium has received extensive attention from scholars.However,the distributed generation of renewable energy has intermittent and random problems.The output power fluctuates with the external environment,which has an impact on the operation of the DC microgrid,which is not conducive to the stable operation of the DC microgrid.Therefore,the source-load-storage coordination Operation is especially important.The traditional DC Bus Signaling(DBS)coordinated control strategy uses the local bus voltage as the information carrier to determine the operating mode and load online state of each interface converter based on a predefined voltage threshold.In the DBS coordinated control strategy,hysteresis control is added at the voltage threshold to eliminate the mode repeat switching problem caused by the disturbance.However,DBS can only ensure the effect of eliminating the disturbance in the voltage hysteresis loop width.Therefore,for the deficiency of DBS coordinated control strategy,a multivariate hysteresis DBS(MVH-DBS)coordinated control strategy based on bus voltage signal is proposed.The main work done in this thesis is as follows:Firstly,the defects of traditional DBS coordinated control are analyzed.On this basis,the MVH-DBS control strategy is proposed,which divides the bus voltage deviation and bus current deviation within the acceptable range into several subregion.The second bus current variable is added between the mode switching points of each region,and the hysteresis control is added,which solves the problem that the single-variable DBS coordinated control causes the mode repeat switching at the voltage segmentation point beyond the ring width disturbance.The existing DBS control has the advantages of scalability and hot plug and play,and improves the anti-interference ability and coordinated operation reliability of the system.Secondly,the photovoltaic cell and battery interface converter are modeled and analyzed,the main circuit parameters of each unit interface converter are given,and the loop of the controller is compensated.Finally,the simulation of the control mode switching of each unit is carried out.Finally,according to the proposed control strategy,the simulation is verified in the DC microgrid model,and the comparison results of the control effect between the MVH-DBS coordinated control strategy and the traditional DBS control strategy are given.At the same time,the code of the MVH-DBS coordination controller is automatically generation and equivalent verification Model-In-the-Loop(MIL)and Software-In-the-Loop(SIL)verification on the PC,testing the model and generating code equivalence,and then using the TMS320F28335 control panel Perform Processor-In-the-Loop(PIL)verification to test the ability of the generated code to run on the development board.