دانلود رایگان مقاله انگلیسی کنترل توزیع ریزشبکه های اینورتر متصل با جریان خطی گذرا محدود - IEEE 2018

Abstract

Distributed generators (DGs) in a microgrid are tightly coupled through power lines, whose dynamics should not be ignored. If not properly handled, large transient line currents may trigger false protection even under normal operating conditions. Droop-based control adjustments also unnecessarily increase frequency and voltage oscillations. Targeting at these problems, this paper presents a distributed control solution for inverterinterfaced microgrids. The objective of primary control is to realize the desired regulations of bus voltages and frequency as well as suppression of transient line currents. The objective of secondary control is to maintain fair load sharing. At secondary control level, a consensus algorithm is introduced to calculate references for phase angles of bus voltages based on fair load sharing and DC power flow. At primary control level, a feedback linearization based control algorithm with dynamic control bounds is designed for voltage regulation and transient line current suppression. In addition to a common reference frame, the subsystem controllers only require measurements of local and neighboring subsystems. The effectiveness of the proposed control solution is demonstrated through simulations based on both simplified and detailed models. Index Terms—Inverter-interfaced microgrids, distributed generator, transient line current, feedback linearization.

V. CONCLUDING REMARKS

Inverter-interfaced microgrids are difficult to control due to fast dynamics, uncertainty, and a wide range of operating conditions. The virtual inertia based control solutions are simple but cannot fully unlock the potentials and advantages of such microgrids. The solutions that integrate droop-based primary control and distributed secondary control cause unnecessary V and f oscillations and cannot effectively manage the magnitude of transient line currents. To overcome these problems, control objectives should be better prioritized and power line dynamics need to be considered. The proposed control solution can not only realize better V and f control by maintaining constant |V| and f references, but also ensure bounded transient line currents during normal operating conditions. By properly adjusting phase angles of bus voltages, both fair load sharing and variable uncertain operating conditions are addressed. The requirement of inter-subsystem communication is also not difficult to be realized with nowadays communication techniques. The effectiveness of the proposed solution has been demonstrated through simulations.

Microgrid control is a challenging topic and deserves long-term and extensive investigation. Future work includes studying more complicated microgrid model, designing improved control algorithms, lowering communication requirements, addressing cyber uncertainties, and testing such control solutions through hardware experimentation.