| High response speed is an essential target to pursue in designing power converters.However,digital control system could hardly reach a high response speed as analog control system,due to its inherent characteristic,even it is increasingly applied on converters.It is necessary to design a fast-response control method that is suitable for digital controller.Inspired by concept of OCC,this paper introduce a control law make converter have finite cycles response time under any disturbance,which is compatible for digital controller.Contributions of this paper are:Firstly,a common digital controlled power converter,three-phase bidirectional VIENNA converter,is chosen to be control plane.Its close-loop state space models under active inversion,passive inversion,and passive conversion,are introduced and further discretized.Secondly,a novel control law to make system converge to equivalent fields within finite cycles under any disturbance,is proposed.Anti-disturbance ability and stability of converter implementing new control law,is analyzed,under a three-phase-balanced condition without parameters perturbation.Meanwhile,a simulation platform based on real-time simulator is established for verification.Thirdly,robustness of system under three-phase-unbalanced condition with parameters perturbation,is further discussed by relevant theory of Zassenhaus equation and H2/H∞control.Then,a parameter tuning method to improve robustness is introduced.Finally,a 300 W prototype is established,and two conventional control laws,constant gain state feedback control law and deadbeat control law,are designed,for comparative experiment.Moreover,a simplified version of the proposed control law is put forward for low-cost low-performed controller.It is shown that the new control law has a better dynamic performance and similar static performance than the conventional two.The simplified one is worse than the original version,but still better than the conventional control methods. |
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