Modified virtual frequency‐voltage frame control scheme with zero sharing error for islanded AC microgrids

• Published in: IET generation, transmission & distribution transmission & distribution, 2023-06, Vol.17 (11), p.2576-2586
• Main Authors: Baharizadeh, Mehdi, Esfahani, Mohammad Sadegh Golsorkhi, Kazemi, Nader
• Format: Article
• Language: English
• Subjects: AC microgrids; decentralized control; distributed energy resources; droop characteristics; power sharing
• ISSN: 1751-8687; 1751-8695
• DOI: 10.1049/gtd2.12837

The active power‐virtual frequency (P‐ω′) and reactive power‐virtual voltage (Q‐V′) droop control scheme has been suggested for coordinated control of distributed energy resources (DERs) in islanded microgrids. While this method mitigates the issue of active and reactive power coupling in the droop controller, its main limitation is power‐sharing error. Due to the local property of the virtual frequency and voltage, significant steady‐state errors occur for both active and reactive power sharing. In this paper, a decentralized method is proposed to eliminate the mentioned errors without utilization of communication links. In the proposed scheme, P‐ω′ and Q‐V′ droops are realized at the microgrid point of common coupling (PCC). By employing the PCC virtual frequency/voltage for the active/reactive power sharing of all DERs, the sharing errors caused by the local property are eliminated. Small signal stability of the proposed scheme is studied, and Hardware‐in‐the‐Loop (HIL) experimental results are presented to validate the proposed method and highlight the improvements compared with the conventional P‐ω′/Q‐V′ scheme. The results verify the efficacy of the proposed method for providing accurate active and reactive power sharing while regulating the frequency and voltage close to the rated values. Active power‐virtual frequency (P‐ω′) and reactive power‐virtual voltage (Q‐V′) droop characteristics suffer from significant errors in active and reactive power sharing. In this paper, to solve the mentioned problem, a decentralized control method in which P‐ω′ and Q‐V′ droops are realized at the microgrid point of common coupling (PCC) is proposed. In this scheme, since common parameters are responsible for active/reactive power sharing among all DERs, the power‐sharing errors are eliminated.