Wenyuan Cao, Minxiao Han, Xiangkun Meng, et al. Reverse Droop Control-based Smooth Transfer Strategy for Interface Converters in Hybrid AC/DC Distribution Networks[J]. CSEE Journal of Power and Energy Systems, 2023, 9(1): 122-134.
DOI:
Wenyuan Cao, Minxiao Han, Xiangkun Meng, et al. Reverse Droop Control-based Smooth Transfer Strategy for Interface Converters in Hybrid AC/DC Distribution Networks[J]. CSEE Journal of Power and Energy Systems, 2023, 9(1): 122-134.DOI: 10.17775/CSEEJPES.2020.02070.
Reverse Droop Control-based Smooth Transfer Strategy for Interface Converters in Hybrid AC/DC Distribution Networks
Hybrid AC/DC distribution networks are promising candidates for future applications due to their rapid advancement in power electronics technology. They use interface converters (IFCs) to link DC and AC distribution networks. However
the networks possess drawbacks with AC voltage and frequency offsets when transferring from grid-tied to islanding modes. To address these problems
this paper proposes a simple but effective strategy based on the reverse droop method. Initially
the power balance equation of the distribution system is derived
which reveals that the cause of voltage and frequency offsets is the mismatch between the IFC output power and the rated load power. Then
the reverse droop control is introduced into the IFC controller. By using a voltage-active power/frequency-reactive power (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$U-P/f-Q$) reverse droop loop
the IFC output power enables adaptive tracking of the rated load power. Therefore
the AC voltage offset and frequency offset are suppressed during the transfer process of operational modes. In addition
the universal parameter design method is discussed based on the stability limitations of the control system and the voltage quality requirements of AC critical loads. Finally
simulation and experimental results clearly validate the proposed control strategy and parameter design method.