Data Driven Based Coordinated Control And Optimized Operation Of Dc Microgrid Cluster

Microgrid is an effective method to increase the proportion of non-fossil energy in primary energy and solve the problem of new energy consumption.Compared with the AC microgrid,the DC microgrid system does not have frequency,phase and other issues,and has the advantages of low line loss,good power supply quality,and easy control.However,a single DC microgrid has limited power capacity and poor inertia,which cannot meet the requirements of power supply reliability.Therefore,the research of DC microgrid group has important practical significance.The topic of the thesis is the coordinated control and optimized operation of the micro-based data-driven DC microgrid group.Its main contents include:1.In order to improve the power distribution accuracy and power quality of the island DC microgrid.A data-driven based model-free secondary control strategy is proposed.Using the input and output process data of the DC microgrid system,the data model of the system is established based on the partial format dynamic linearization method,which does not require the model parameters of the microgrid system and the prior knowledge of primary control,and has better robustness.Then,a new model-free secondary power and voltage controller was designed to make the distributed power supply output power in proportion to its capacity,while using the maximum voltage compensation method to restore the system bus voltage.2.The DC microgrid operating in islands has no support from a large power grid,so higher requirements are put forward on the control of the system.Under traditional droop control,the existence of mismatched line impedance reduces the accuracy of load power distribution,which is not conducive to the stable operation of the microgrid.At the same time,in actual engineering,the line impedance,device parameters,and load requirements are unknown in some cases.It is difficult to build an accurate system model,and the inaccuracy of the model may reduce the effect of the controller.For this reason,this chapter proposes an observer-based DC microgrid model-free secondary control to realize the proportional distribution of load power and the restoration of bus voltage.3.Due to the continuous increase in load demand and the high permeability of distributed power sources,it is difficult for a single microgrid to meet the requirements of power supply reliability.At this time,multiple nearby DC microgrids can be connected to each other to form a DC microgrid group.This chapter proposes a data-driven hierarchical control strategy for DC microgrid groups operating in islands.Data-driven model-free adaptive secondary control(MFASC)is used for precise power and voltage control of a single DC microgrid.A sliding mode observer is designed to observe the pseudo partial derivative(PPD)of MFASC,which improves the accuracy of PPD observation and achieves a better control effect.The third control is used to realize the global power correction of the DC microgrid group.