TY - JOUR
T1 - An Improved Virtual Inertia Control for Three-Phase Voltage Source Converters Connected to a Weak Grid
AU - Fang, Jingyang
AU - Lin, Pengfeng
AU - Li, Hongchang
AU - Yang, Yongheng
AU - Tang, Yi
PY - 2019/9
Y1 - 2019/9
N2 - The continuous increasing share of power-converter-based renewable energies weakens the power system inertia. The lack of inertia becomes a main challenge to small-scale modern power systems in terms of control and stability. To alleviate adverse effects from inertia reductions, e.g., undesirable load shedding and cascading failures, three-phase grid-connected power converters should provide virtual inertia upon system demands. This can be achieved by directly linking the grid frequency and voltage references of dc-link capacitors/ultracapacitors. This paper reveals that the virtual inertia control may possibly induce instabilities to the power converters under weak grid conditions, which is caused by the coupling between the d- and q-axes as well as the inherent differential operator introduced by the virtual inertia control. To tackle this instability issue, this paper proposes a modified virtual inertia control to mitigate the differential effect, and thus, alleviating the coupling effect to a great extent. Experimental verifications are provided, which demonstrate the effectiveness of the proposed control in stabilizing three-phase grid-connected power converters for inertia emulation even when connected to the weak grid.
AB - The continuous increasing share of power-converter-based renewable energies weakens the power system inertia. The lack of inertia becomes a main challenge to small-scale modern power systems in terms of control and stability. To alleviate adverse effects from inertia reductions, e.g., undesirable load shedding and cascading failures, three-phase grid-connected power converters should provide virtual inertia upon system demands. This can be achieved by directly linking the grid frequency and voltage references of dc-link capacitors/ultracapacitors. This paper reveals that the virtual inertia control may possibly induce instabilities to the power converters under weak grid conditions, which is caused by the coupling between the d- and q-axes as well as the inherent differential operator introduced by the virtual inertia control. To tackle this instability issue, this paper proposes a modified virtual inertia control to mitigate the differential effect, and thus, alleviating the coupling effect to a great extent. Experimental verifications are provided, which demonstrate the effectiveness of the proposed control in stabilizing three-phase grid-connected power converters for inertia emulation even when connected to the weak grid.
KW - Frequency regulation
KW - Power converter
KW - Renewable energy
KW - Stability
KW - Virtual inertia
KW - Weak grid
UR - http://www.scopus.com/inward/record.url?scp=85058164308&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2018.2885513
DO - 10.1109/TPEL.2018.2885513
M3 - Journal article
SN - 0885-8993
VL - 34
SP - 8660
EP - 8670
JO - I E E E Transactions on Power Electronics
JF - I E E E Transactions on Power Electronics
IS - 9
M1 - 8567928
ER -