Research On Bidirectional AC/DC Control Strategy Of Photovoltaic And Energy Storage DC Microgrid

With the rapid development of today’s world and people’s increasing demand for various energy sources,and the non-renewable energy sources on the earth are decreasing day by day,people are turning to new energy sources.Based on this,this paper makes an in-depth analysis of the operation mode of the bidirectional AC/DC converter in the optical storage DC microgrid,and proposes a new double closed-loop control strategy based on traditional PI control and an improved model prediction based on adaptive sliding mode.The power control strategy and the corresponding simulation model are established.Finally,the feasibility of the strategy is verified through experiments.The research content of this article is as follows:(1)The overall structure of the optical storage DC microgrid is introduced,the working mode of the bidirectional AC/DC converter in grid connection mode is analyzed,the topology structure of the bidirectional AC/DC converter is introduced,and the coordinate transformation theory The mathematical model of the bidirectional AC/DC converter in three coordinate systems is established.(2)For the bidirectional AC/DC converter,the three control strategies of traditional direct current control,traditional direct power control and model predictive control are analyzed in detail,and the corresponding simulation model is built in MATLAB/Simulink.The dynamic response of traditional direct current control is slow,and the ability to resist load disturbance is poor;the switching frequency of traditional direct power control is not fixed,the power adjustment is slow under single vector control,and the AC side current is distorted;and the model predictive control has good dynamic and static The effect has strong anti-interference ability.(3)Aiming at the problems of slow dynamic response and poor load disturbance resistance of traditional direct current control,a new double closed-loop control strategy based on traditional PI control is proposed,and its regulator is related to the design;On the basis of this,an improved model prediction adaptive power control strategy based on adaptive sliding mode is proposed,and the mathematical model of the bidirectional AC/DC converter under this strategy is established.(4)Complete the construction of the hardware circuit part of the bidirectional AC/DC converter,mainly including the design of signal sampling and conditioning circuit,drive circuit,protection circuit,etc.,while the software part mainly completes the main program,interrupt service program and various functions Module subprogram design.In order to verify the feasibility of the two new control strategies mentioned in the article,a two-way AC/DC experimental platform was built,and the experimental waveforms obtained were analyzed and compared.