Electronic Science and Technology ›› 2022, Vol. 35 ›› Issue (7): 79-86.doi: 10.16180/j.cnki.issn1007-7820.2022.07.013

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Comparison of Coordinated Control between Front and Rear Stages of Isolated AC-DC Solid-State Transformers

ZHENG Zheng,JIANG Pengfei,ZHANG Guopeng,LI Zihan   

  1. School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454003,China
  • Received:2021-01-21 Online:2022-07-15 Published:2022-08-16
  • Supported by:
    Henan Science and Technology Project(21202102210294);Henan Polytechnic University Doctoral Fund(B2015-32)

Abstract:

Isolated AC-DC solid-state transformers widely use the front and rear multi-stage cascade structure of the bidirectional converter. Due to the difference in the control bandwidth of the front and rear stages, the transmission power of the two stages is different. When the power suddenly changes, the difference will seriously threaten the operational safety of this type of SST. In view of this problem, this study analyzes the mechanism of the power difference between the stages, summarizes various control strategies to reduce the power fluctuations between the stages, and derives the mathematical model of the load disturbance on the voltage between the two stages under different strategies. Using MATLAB, the closed-loop Bode plots of various typical control strategies and the corresponding step responses in the time domain are obtained, and the advantages and disadvantages of various strategies are compared horizontally. Finally, simulation and experiment results verify the correctness and validity of the analysis and comparison results.

Key words: solid-state transformer, bidirectional converter, control bandwidth, power difference between stages, load disturbance, Bode plot, step response, horizontal contrast

CLC Number: 

  • TN7