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Summary: Bridgeless ac‐dc converters are the optimal choice for many applications, as they offer many advantages such as low distorted supply current, high power factor, and improved efficiency. This paper presents a new topology for a single‐phase bridgeless ac‐dc converter. The proposed hybrid topology is based on integrating the inverting and non‐inverting buck‐boost dc‐dc converters that are connected to the ac supply through an LC filter. To insure sinusoidal supply current, the proposed hybrid bridgeless ac‐dc converter is operated in discontinuous current mode. The proposed converter has many merits, such as a reduced number of components, enhanced efficiency, and soft start‐up capability. The operation modes and design of the proposed converter are presented. In addition, a design method is proposed for the input LC filter to minimize the voltage stress across switches. Moreover, a small signal model for the proposed converter is developed. The proposed converter topology is simulated to evaluate the dynamic behavior and verify the accuracy of the presented small signal model. Furthermore, an 850 W prototype is developed to validate the features of the proposed converter experimentally. Tight voltage regulation, sinusoidal supply current, and near‐to‐unity power factor operation are observed from the results, regardless of supply or load disturbances. [ABSTRACT FROM AUTHOR]

Due to the growing attention for the environmental impacts and power loss minimization, distributed generators (DGs) have been introduced widely into the electric power system. One of the challenges of integrating with the power system is to determine their optimal placement and sizing, which, when not respected, adversely affects the performance of the electrical network. In this paper, three multi‐objective algorithms of particle swarm optimization (PSO), variable constants (VCPSO) and genetic algorithm (GA) are adopted and implemented. The main objectives are to detect the optimum size and location of multiple DGs aiming to reduce the active power loss and improve bus voltage deviations in the distribution networks. The paper conducts a comprehensive review of the optimal size and location of the DG via systematic procedures, including definition, classifications, technologies of DGs. Then, the performances evaluation of the three optimization methods are presented and compared with other methods. The presented optimization methods are tested on the IEEE‐33 bus, 32‐line radial distribution network. Four different scenario‐based studies including base case and different number of DGs are performed to examine the accuracy of the presented algorithms. The obtained results prove that all the three algorithms are suitable for this multi‐objective optimization and VCPSO offers the best solution in terms of convergence and, and it has lowest average computation time. The performance and accuracy of the presented approaches and their improvements in the power loss and bus voltage profile are discussed and presented in detail. The obtained results show that more than 65% of active power loss reduction has been attained with the proper sizing and placement of DG systems. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Dusty weather is a most important disturbance for photovoltaic (PV) systems, that may result in PV panels exposure to partial shading conditions where the PV panel characteristics show several maximum power points. Moreover, dusty weather conditions may lead to rapid changes in solar radiations. Thus, conventional power system tracking algorithms are not being capable to track the global maximum power point (GMPP). This paper provides an advanced maximum power point tracker for partial shading and dusty weather conditions. In the presented technique, scanning and power lock conditions are added to the conventional perturbations and observation technique in photovoltaic system under partial shading or dusty weather conditions. This tracking method scans the PV characteristic in steps and stores all the maximum power points in order to get the GMPP. The proposed tracker is capable to identify the uniform weather conditions to save it from having unnecessary scanning. In addition, this tracker permits dynamic tracking of the GMPP under dusty weather conditions with less fluctuations and stable operation compared to the conventional methods. Accurate and fast conversion to the GMPP during various weather conditions is accomplished using the proposed technique. The proposed modified perturb and observe technique is validated using simulation and practical results. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This study proposes a new back-to-back (BTB) current source converter (CSC) configuration and presents its application for variable speed wind energy conversion system. The proposed configuration consists of three cascaded ac−dc non-inverting buck-boost converter. The ac side of each converter is connected to an open-end winding of the three-phase permanent magnet synchronous generator and the dc sides are connected in parallel to a current source inverter (CSI) without the need for a dc-side capacitor. Ac−dc converters operate under discontinuous conduction mode, and they draw sinusoidal input currents at the unity power factor from fixed or variable magnitude and frequency supply. In addition, the proposed BTB CSC addresses one of the main drawbacks of the conventional CSI which is the over-voltage experienced by switches during commutation. Moreover, the switching losses of the proposed CSI are eliminated. The ElectroMagnetic Transients including DC (EMTDC)/Power System Computer Aided Design (PSCAD) software is used to assess the feasibility of the proposed topology during normal operating conditions and during low voltage ride through. [ABSTRACT FROM AUTHOR]