TY - JOUR
T1 - Active Power Sharing and Frequency Restoration in an Autonomous Networked Microgrid
AU - Eskandari, M.
AU - Li, L.
AU - Moradi, M. H.
AU - Siano, P.
AU - Blaabjerg, F.
PY - 2019/11
Y1 - 2019/11
N2 - Microgrid (MG) concept is considered as the best solution for future power systems, which are expected to receive a considerable amount of power through renewable energy resources and distributed generation units. Droop control systems are widely adopted in conventional power systems and recently in MGs for power sharing among generation units. However, droop control causes frequency fluctuations, which leads to poor power quality. This paper deals with frequency fluctuation and stability concerns of f-P droop control loop in MGs. Inspired from conventional synchronous generators, virtual damping is proposed to diminish frequency fluctuation in MGs. Then, it is demonstrated that the conventional frequency restoration method inserts an offset to the phase angle, which is in conflict with accurate power sharing. To this end, a novel control method, based on phase angle feedback, is proposed for frequency restoration in conjunction with a novel method for adaptively tuning the feedback gains to preserve precise active power sharing. Nonlinear stability analysis is conducted by drawing the phase variations of the nonlinear second-order equation of the δ-P droop loop and it is proved that the proposed method improves the stability margin of f-P control loop. Simulation results demonstrate the effectiveness of the proposed method.
AB - Microgrid (MG) concept is considered as the best solution for future power systems, which are expected to receive a considerable amount of power through renewable energy resources and distributed generation units. Droop control systems are widely adopted in conventional power systems and recently in MGs for power sharing among generation units. However, droop control causes frequency fluctuations, which leads to poor power quality. This paper deals with frequency fluctuation and stability concerns of f-P droop control loop in MGs. Inspired from conventional synchronous generators, virtual damping is proposed to diminish frequency fluctuation in MGs. Then, it is demonstrated that the conventional frequency restoration method inserts an offset to the phase angle, which is in conflict with accurate power sharing. To this end, a novel control method, based on phase angle feedback, is proposed for frequency restoration in conjunction with a novel method for adaptively tuning the feedback gains to preserve precise active power sharing. Nonlinear stability analysis is conducted by drawing the phase variations of the nonlinear second-order equation of the δ-P droop loop and it is proved that the proposed method improves the stability margin of f-P control loop. Simulation results demonstrate the effectiveness of the proposed method.
KW - Power system stability
KW - Frequency control
KW - Stability analysis
KW - Power system dynamics
KW - Voltage control
KW - Control systems
KW - Circuit stability
KW - Distributed generation (DG)
KW - Droop control
KW - Frequency restoration
KW - Microgrid (MG)
KW - Power control
KW - Renewable energy resources (RESs)
KW - Distributed generation (DG)
KW - Droop control
KW - Frequency restoration
KW - Microgrid (MG)
KW - Power control
KW - Renewable energy resources (RESs)
UR - http://www.scopus.com/inward/record.url?scp=85074578733&partnerID=8YFLogxK
U2 - 10.1109/TPWRS.2019.2923797
DO - 10.1109/TPWRS.2019.2923797
M3 - Journal article
SN - 0885-8950
VL - 34
SP - 4706
EP - 4717
JO - IEEE Transactions on Power Systems
JF - IEEE Transactions on Power Systems
IS - 6
M1 - 8740943
ER -