Performance Improvement Strategy for Parallel-operated Virtual Synchronous Generators in Microgrids

Hui Zhang; Ruixue Zhang; Kai Sun; Wei Feng

Performance Improvement Strategy for Parallel-operated Virtual Synchronous Generators in Microgrids

Vol. 19, No. 2, pp. 580-590, Mar. 2019

10.6113/JPE.2019.19.2.580

Active-frequency droop coefficient

Power oscillation

Virtual synchronous generator (VSG)

Virtual synchronous reactance

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Abstract

The concept of virtual synchronous generators (VSGs) is a valuable means for improving the frequency stability of microgrids (MGs). However, a great virtual inertia in a VSG’s controller may cause power oscillation, thereby deteriorating system stability. In this study, a small-signal model of an MG with two paralleled VSGs is established, and a control strategy for maintaining a constant inertial time with an increasing active-frequency droop coefficient (m) is proposed on the basis of a root locus analysis. The power oscillation is suppressed by adjusting virtual synchronous reactance, damping coefficient, and load frequency coefficient under the same inertial time constant. In addition, the dynamic load distribution is sensitive to the controller parameters, especially under the parallel operation of VSGs with different capacities. Therefore, an active power increment method is introduced to improve the precision of active power sharing in dynamic response. Simulation and experimental is used to verify the theoretical analysis findings.

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Cite this article

[IEEE Style]

H. Zhang, R. Zhang, K. Sun, W. Feng, "Performance Improvement Strategy for Parallel-operated Virtual Synchronous Generators in Microgrids," Journal of Power Electronics, vol. 19, no. 2, pp. 580-590, 2019. DOI: 10.6113/JPE.2019.19.2.580.

[ACM Style]

Hui Zhang, Ruixue Zhang, Kai Sun, and Wei Feng. 2019. Performance Improvement Strategy for Parallel-operated Virtual Synchronous Generators in Microgrids. Journal of Power Electronics, 19, 2, (2019), 580-590. DOI: 10.6113/JPE.2019.19.2.580.