TY - JOUR
T1 - Performance improvement of the unbalanced voltage compensation in islanded microgrid based on small-signal analysis
AU - Peng, Yelun
AU - Shuai, Zhikang
AU - Guerrero, Josep M.
AU - Li, Yong
AU - Luo, An
AU - Shen, Zheng John
PY - 2020/7
Y1 - 2020/7
N2 - A low-voltage microgrid is naturally three-phase unbalance due to the connection of unbalanced loads. Voltage unbalance compensation (VUC) strategies of inverters have been proposed to compensate the voltage unbalance on the point of common coupling. However, the small-signal analysis of these VUC strategies has not been investigated in a microgrid with multiple inverters, which is due to the difficulty of the state-space modeling for unbalanced microgrids. This lack of discussion may result in a poor performance of the microgrid when the parameters of VUCs are not well designed. To investigate the dynamic behavior of the unbalanced microgrid with VUC strategies, this article develops a detailed state-space model for an unbalanced microgrid using the dynamic phasor method. Then, based on the developed model, small-signal analysis is carried out to investigate the effect of the VUC control on the dynamic behavior of a microgrid. It is found that a poor design of the VUC controllers may result in the instability of the microgrid. Finally, an improved compensation method with better compensation performance is proposed. Experimental results are used to validate the effectiveness of the proposed method.
AB - A low-voltage microgrid is naturally three-phase unbalance due to the connection of unbalanced loads. Voltage unbalance compensation (VUC) strategies of inverters have been proposed to compensate the voltage unbalance on the point of common coupling. However, the small-signal analysis of these VUC strategies has not been investigated in a microgrid with multiple inverters, which is due to the difficulty of the state-space modeling for unbalanced microgrids. This lack of discussion may result in a poor performance of the microgrid when the parameters of VUCs are not well designed. To investigate the dynamic behavior of the unbalanced microgrid with VUC strategies, this article develops a detailed state-space model for an unbalanced microgrid using the dynamic phasor method. Then, based on the developed model, small-signal analysis is carried out to investigate the effect of the VUC control on the dynamic behavior of a microgrid. It is found that a poor design of the VUC controllers may result in the instability of the microgrid. Finally, an improved compensation method with better compensation performance is proposed. Experimental results are used to validate the effectiveness of the proposed method.
KW - Dynamic-phasor (DP) method
KW - islanded microgrid (MG)
KW - stability analysis
KW - three-phase unbalance
KW - unbalanced voltage compensation
UR - http://www.scopus.com/inward/record.url?scp=85081725053&partnerID=8YFLogxK
U2 - 10.1109/TIE.2019.2934021
DO - 10.1109/TIE.2019.2934021
M3 - Journal article
AN - SCOPUS:85081725053
SN - 0278-0046
VL - 67
SP - 5531
EP - 5542
JO - IEEE Transactions on Industrial Electronics
JF - IEEE Transactions on Industrial Electronics
IS - 7
M1 - 8805485
ER -