A Comprehensive Review on Power Converters Control and Control Strategies of AC/DC Microgrid

Abstract

Owing to the smart lifestyle, environmental consciousness, and dwindling fossil fuel supplies, there is a huge demand for clean and green energy. Microgrid (MG) is a crucial approach to renewable and clean energy. Because of the success of the AC utility grid and the growing demand for critical loads, it is very convenient to provide AC/DC MG that can easily satisfy both the alternating current (AC) MG and the direct current (DC) MG requirements. Due to uncertainty in load variations, main grid failures, intermittent power generations from renewable energy sources (RESs), the synchronization and interconnection of different power converters are the paramount issues in the control of AC/DC MG. This paper presents an overview-oriented state of the art in the recent advancement in control strategies of AC/DC MG and its associated power converters control. Based on recent research, this paper summarizes unobstructed views on different topologies, types of power converters, power converter controls, and control strategies of AC/DC MG. Finally, it identified some future challenges that need to be addressed in order to develop a sustainable and reliable control strategy for AC/DC MG. This paper will serve as a guide for researchers. INDEX TERMS Distributed generation, Microgrids, AC/DC Microgrid, Centralized control, Decentralized control I. INTRODUCTION MGs compromise different RESs, i.e., PV cells, windmills, energy-storing systems (ESS), diesel generator sets, and small hydropower plants, as discussed in the [1,2]. With the advancements in power semiconductor devices, the integration of RESs with leading utility or MG becomes so more accessible. Based on the adopted topology, there are three types of MGs, classified as DC MG, AC MG, and AC/DC MG or hybrid MG [3]. The DC MGs are preferred to supply critical loads like computers, operation theatres, and billing counters. Whereas the AC MGs are preferred in supplying all loads during off-grid or on-grid. The AC/DC MG possesses the characteristics of both DC MG and AC MG. Since begin, in these types of MGs, the power converters are connected in parallel with the MG bus-bar and belong to the parallel topology of MG. Recently a seriescascaded MG topology is being investigated. Inam Ullah Nutkani and et al. in [4] has presented a series-cascaded AC MG topology to integrate the non-dispatchable RESs to the MG and offered its advantages and disadvantages over the parallel topology. Fig.1 shows the different topological advances of MGs.

Investigation of Microgrid Hierarchical Control and Structure

“…In this level, measurements are local voltages and currents [33,37]. In centralized control, local control is installed in the location of controllable loads and is usually used for demand-side management [38].…”

“…The difference between the centralized and decentralized control is determined by defined tasks for the MGCC and tasks divided between MGCC, MC, and LC. In the centralized control, MC and LC perform the MGCC commands in grid-connected mode, and in islanded mode, decision-making is performed by MC and LC [38].…”

Review of a Disruptive Vision of Future Power Grids: A New Path Based on Hybrid AC/DC Grids and Solid-State Transformers

“…In [31], a review of interconnected microgrids is presented from a perspective of resilience, robustness, and efficiency, where methodologies for the operation and control of microgrids are highlighted, as well as opportunities, challenges, and possible innovative solutions for microgrids. In [32], a comprehensive review of control algorithms for power electronics converters is presented, as well as control strategies for AC/DC microgrids. In this context, dedicated control strategies and synchronization mechanisms also assume a relevant preponderance for different scenarios of application, e.g., a remote microgrid synchronization avoiding the necessity of measurements at the point of common coupling is proposed in [33], adaptive synchronization mechanisms for power converters are proposed in [34], and advanced synchronization control of power converters in microgrids is proposed in [35].…”

A Power Control Method for Hybrid Electrical Accommodation Systems

“…Another issue is that, while many control techniques for AC sub-grids have been studied, control techniques for DC sub-grids are still rare [6,18,[22][23][24][25]. This is understandable, since AC grids play a dominant role in traditional distribution systems, and the techniques used in traditional AC grids can be applied to sub-grids.…”