Aiming at the poor dynamic characteristics of the dual active bridge DC converter in the DC microgrid system when the system is disturbed and the low efficiency of the converter under the single phase-shift modulation,this paper proposes a super twisting sliding mode control strategy combined with the backflow power optimization under the extended phase-shift modulation.Firstly,the transmission power,the backflow power mathematical model and the soft-switching characteristics of the two modes of the dual-active-bridge(DAB)converter under the extended phase-shift modulation are analyzed,and the reduced-order model of the DAB converter is established based on the transmission power mathematical model.Secondly,with the backflow power as the objective function and the transmission power and soft-switching characteristics as the constraints,the optimal combination of the shift phases is found through the Karush-Kuhn-Tucker conditional method;The DAB converter reduced order model is used to design the equivalent part in the super twisting sliding mode control and the super twisting algorithm is used as the switching part.These two parts work together with the inner shifting ratio D1 to generate the outer shifting ratio D2,which is used to adjust the output voltage of the converter.Finally,the simulation and experimental verification is carried out,and the results show that the converter has a good dynamic performance when the load is switched,the input voltage changes suddenly,and the reference voltage changes,effectively reducing the backflow power.
关键词
双有源桥直流变换器/超螺旋滑模控制/动态性能/KKT条件法/回流功率
Key words
dual active bridge DC converter/super twisting sliding mode control/dynamic performance/KKT conditional method/backflow power
维普
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