Control Method of Seamless Transfer from Grid-Connected Mode to Isolated Mode for Microgrid Demonstration

• Published in: Journal of physics. Conference series Vol. 2557; no. 1; pp. 12001 - 12006
• Main Authors: Wu, MeiRong, Xue, Fei, Ren, Yong
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.07.2023
• Subjects: Control methods; Controllers; Distributed generation; Phase locked loops; Physics; Switching; Transient oscillations
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/2557/1/012001

Abstract It’s easy to cause transient oscillation problems when the microgrid transfers from the grid-connected mode to the isolated mode, so a control method of seamless transfers from the grid-connected mode to the isolated mode for microgrid demonstration is proposed. The switching control strategy of the outer loop controller for the master unit(s) makes the reference value of the current inner-loop controller the same when the microgrid transfers to isolated mode. While the switching control strategy of phase locked loop (PLL) uses an ample-hold assign the output angle of grid-connected PLL to the oscillator adopted by the microgrid in isolated mode at the switching moment. Finally, the sub-regional control strategy uses different control strategies to reserve more spinning capacity for the master unit(s) which divides the power balance into 3 regions. At last, the simulation is verified that the proposed control method not only realizes the seamless transfer from grid-connected operation to islanded operation for the microgrid but also improves the anti-disturbance ability of the microgrid in isolated mode.