Energy Reports (Nov 2022)

Coordinated control strategies for unbalanced voltage suppression and optimization of SOC of battery in a bipolar DC microgrid with voltage balancer

  • Shuyin Tan,
  • Jianquan Liao,
  • Xuan Liu,
  • Chunsheng Guo,
  • Yu Zhang,
  • Qianggang Wang

Journal volume & issue
Vol. 8
pp. 13199 – 13210

Abstract

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The unbalanced loads and distributed generations (DGs) will lead to an unbalanced current in the neutral line and further result in a voltage imbalance which will increase circuit power consumption and affect the stable operation of the bipolar DC microgrid. The application of a voltage balancer (VB) can address the issue of unbalanced voltage and current. In this paper, the proposed coordinated control strategy can realize VB to provide a reference voltage to voltage source converter (VSC), battery energy management system (BEMS), and photovoltaic (PV) power generation. The essence of the proposed coordinated control strategy is to adaptively adjust the voltage droop coefficient, which can realize the suppression of unbalanced voltage, power sharing, and regulation of battery state of charge (SOC). In this research, the coordinated control structure of VB and the control scheme of BEMS are investigated. In addition, the small-signal model of the bipolar DC microgrid is also presented to show the system involved is stable. Subsequently, the effectiveness of the proposed coordinated control strategies is verified in MATLAB/Simulink software.

Keywords