Droop control in DQ coordinates for fixed frequency inverter-based AC microgrids

This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each other through power converters. An inherent property of inverter-based microgrids is that, unlike microgrids with spinning machines, the frequency of the parallel-connected DGUs is a global variable independent from the output power since the inverters can control the output waveform frequency with a high level of precision. Therefore, conventional droop control methods that distort the system frequency are not suitable for microgrids operating at a fixed frequency. It is shown that the proposed distributed droop control allows accurate sharing of the active and reactive power without altering the microgrid frequency. The simulation and hardware-in-the-loop (HIL) results are presented to demonstrate the efficacy of the proposed droop control. Indeed, following a load change, the dq droop controller was able to share both active and reactive power between the DGUs, whereas maintaining the microgrid frequency deviation at 0% and the bus voltage deviations below 6% of their respective nominal values

Optimum MPPT technique for reconfiguring the photovoltaic array under partial shading failure

Partial shading (PS) considerably restricts photovoltaic (PV) systems, requiring extraction of the global maximum power point (GMPP). This persistent challenge engenders continuous fluctuations in the maximum power point (MPP) and demands utmost attention. In this regard, this paper presents a novel hybrid scanning technique and a Perturb and Observe (P&O) algorithm meticulously designed to accurately track the PV array’s GMPP encountering PS, non-uniform dust deposition, or any common failures. Furthermore, it serves as an efficient tool that operates in tandem with the dynamic reconfiguration approaches. Extensive simulation tests were carried out using MATLAB Simulink software, while the validation and verification processes were conducted using an integrated Arduino board. Consequently, the simulation results exhibit outstanding accuracy and stabilit

Multiobjective Optimization of Renewable Energy Penetration Rate in Power Systems

AbstractNowadays, multi-source systems based on renewable energy technologies become the key to a sustainable energy supply infrastructure against the rising cost and the pollutant nature of fossil primary energy used in conventional power plant. However, the cost of renewable energy technologies and the reliability of a multi-sources generation system are generally conflicting with each other. This paper presents a multiobjective formulation to allow optimizing simultaneously both the annualized renewable energy cost the system reliability defined as the renewable energy - load disparity (RELD). This later takes into account the lack of energy as well as the exceed weighted by a penalty factor. The optimization is reach by acting on the penetration rate of each type of renewable generation technologies in order to satisfy a certain load curve. In order to solve this problem, this work suggests to use the fast and elitist multiobjective genetic algorithm: NSGA-II. A case study shows that the use of diversified resources allows to handle the RELD and to decrease the exceed renewable energy (RERE) and load energy notsupplied (LENS)

Decentralized Hamiltonian control of multi-DEr isolated microgrids with meshed topology

© 2019 The Authors. Published by Elsevier Ltd. The new electricity grid of the future, smart grid, can be seen as the interconnection of multiple microgrids. These microgrids are usually composed of distributed energy resources (DERs) that connect to each other in different topologies. Therefore, the modeling and control of meshed microgrids are requisite. This paper presents a mathematical approach for the modeling and decentralized control of multi-DER isolated microgrids (ImGs) with a meshed topology. Based on the advanced control scheme: Hamiltonian surface shaping and power flow control (HSSPFC), decentralized controllers are designed independently using only local information. These controllers regulate the voltage at the point of common coupling (PCC) of their respective DERs and guarantee the stability of the overall ImG without requiring any communication infrastructure; hence, avoiding a single point of failure and harvesting the scalability of the ImG