Wireless Power Transfer (WPT) using inductive and magnetic resonance coupling developing at enormous pace due to its diversity of applications, such as electric vehicles (EV), biomedical implants, consumer electronics, robotics and so on. This review presents historical background together with applications of low power and high power WPT systems. The review emphasizes on two main design facets of WPT system including compensation networks and coil structure. All up-to-date compensation topologies are comprised in the review along with latest coil designs. Load-independent operation using compensation topologies is also reviewed. The review provides all available methods to analyze the circuit structure of WPT system theoretically and it also outlines the software used for circuit simulations as well as coil design. This paper is diverse from existing reviews in a pattern that it presents not only complete critical intuition on the vital design features, recent advancements, contemporary problems and challenges of low power and high power WPT systems but also provides the available theoretical methods as well as software to analyze the WPT system in wholesome. This paper will enrich the knowledge of the researchers to investigate the WPT systems using existing techniques and to solve the present-day design glitches of WPT systems.

Producing energy from a variety of sources in a power system requires an optimal schedule to operate the power grids economically and efficiently. Nowadays, power grids might include thermal generators and renewable energy sources (RES). The integration of RES adds complexity to the optimal power flow problem due to intermittence and uncertainty. The study suggests a Multi-Objective Search Group Algorithm (MOSGA) to deal with multi-objective optimal power flow integrated with a stochastic wind and solar powers (MOOPF-WS) problem. Weibull and lognormal probability distribution functions (PDFs) are respectively adopted to describe uncertainties in wind speed and solar irradiance. The MOSGA incorporates crowding distance strategies, fast non-dominated sorting, and an archive selection mechanism to define and preserve the best non-dominated solutions. The total cost, real power loss, and emission were defined as the objectives for the MOOPF-WS problem. In the economic aspect, formulated cost modelling includes both overestimation and underestimation situations related to wind and solar power prediction. Further, uncertainty in load demand is represented by a normal PDF and is considered as a special study case due to its novelty. The effectiveness of MOSGA was validated on the IEEE 30-bus and 57-bus systems considering various combinations of objective functions as well as different loading scenarios. Its performance was comprehensively compared with the other three well-regarded multi-objective optimization algorithms including NSGA-II, MOALO, and MOGOA in terms of Spread metric, Hypervolume metric, and the best compromise solutions for all scenarios. The comparisons showed MOSGA was capable of obtaining well-distributed Pareto fronts and producing better quality solutions compared to the others in all tested scenarios. In addition, MOSGA also obtained better solution quality than significant research in the literature for all the comparable cases. These show the superiority of the MOSGA in dealing with the MOOPF-WS problem.

In this study, a novel reconfigurable triple-band monopole antenna for LoRa IoT applications is fabricated on an FR-4 substrate. The proposed antenna is designed to function at three distinct LoRa frequency bands: 433 MHz, 868 MHz, and 915 MHz covering the LoRa bands in Europe, America, and Asia. The antenna is reconfigurable by using a PIN diode switching mechanism, which allows for the selection of the desired operating frequency band based on the state of the diodes. The antenna is designed using CST MWS^® software 2019 and optimized for maximum gain, good radiation pattern and efficiency. The antenna with a total dimension of 80 mm × 50 mm × 0.6 mm (0.12${\lambda }_0\times 0.07{\lambda }_0$ × 0.001${\lambda }_0$ at 433 MHz) has a gain of 2 dBi, 1.9 dBi, and 1.9 dBi at 433 MHz, 868 MHz, and 915 MHz, respectively, with an omnidirectional H-plane radiation pattern and a radiation efficiency above 90% across the three frequency bands. The fabrication and measurement of the antenna have been carried out, and the results of simulation and measurements are compared. The agreement among the simulation and measurement results confirms the design’s accuracy and the antenna’s suitability for LoRa IoT applications, particularly in providing a compact, flexible, and energy efficient communication solution for different LoRa frequency bands.

Microgrids (MG), considered the future of power systems, has gained significant attention in the present time. MG’s inherent capability of combining both AC and DC operations in a single frame. Its function is crucial in achieving a sustainable electricity supply and advances a decentralized power system approach. MG not only combines the benefits of both AC and DC but also incorporates distributed generations (DGs) and distributed renewable energy sources (DREs). However, the advancement of DGs and DREs with power electronics interfaces (PEIs), and smart loads (SLs) poses the dynamic nature of DGs and DREs such as bi-directional power flow and varying output, which has introduced certain protection challenges in MG maneuver. Therefore, this paper reviews the protection challenges in MG and critically addresses the assessment of existing protection schemes developed so far. It also categorizes the MG protection issues including its components and faults separately for both AC and DC MGs and analyzes the performance of measurement and protection techniques for MG protection strategy on the basis of operational modes AC and DC MGs.

The concentrating photovoltaic/thermal (PVT) collectors offer the benefits of the reduced per-unit price of electrical energy and co-generation of electrical and thermal energies by intensifying the solar irradiation falling on the hybrid receiving plane. The compound parabolic concentrating (CPC) collectors have appeared as a promising candidate for numerous applications in the field of solar energy due to their ability to collect both direct and diffuse solar radiation and suitability for stationary installation. Over the last few decades, various configurations of CPC collectors have been proposed and investigated by different researchers for the simultaneous generation of electrical and thermal energies. This article presents a comprehensive review of historical and recent developments and applications of CPC-based hybrid PVT systems. The review focuses on the heat extraction mechanisms and commonly used application areas of CPC-PVT systems. The innovative design configurations proposed by different researchers have been reviewed in detail. The outputs of CPC-PVT systems are generally found to be superior to their counterparts without CPCs, which justifies their increased popularity. Due to dual outputs, the hybrid CPC-PVT systems are considered to be suitable for rooftop and building façade integrated applications. Finally, future recommendations have been enlisted, highlighting the potential research opportunities and challenges for the prospective researchers working in the field of concentrating solar PVT systems.

The growing tendency of wind energy technology usage has induced researchers to seek more studies on the improvement of wind energy harvesting systems with highly reliable power injected into the electric grid. The amount of extracted wind energy by a wind turbine depends on the accuracy of the maximum power point tracking (MPPT) algorithm associated with the control scheme of the wind energy conversion system (WECS). This paper aims to present a novel development of MPPT algorithm based on parabolic prediction techniques (PPT) for variable speed wind turbines (VSWT) so as to achieve maximum wind power extraction and efficiency enhancement. The developed PPT-MPPT algorithm uses parabolic convex functions to estimate the parabola wind turbine output curve and locate the maximum power point on that curve. Simultaneously the algorithm establishes a systematic procedure for adjusting the concavity and the optimal part of the estimated parabola curve to make sure that the proposed technique is in continuous convergence. The feasibility of the developed PPT-MPPT algorithm has been validated under rapid and random changing wind speed profiles via the MATLAB/Simulink environment. The performance of the proposed PPT-MMPT algorithm is evaluated by comparing the simulation finding to those obtained using the benchmark perturb and observe(P&O) algorithms. The simulation outcomes affirm that the proposed PPT-MPPT algorithm outperformed the other algorithms in terms of tracking efficiency and extracted power which can be regarded as an efficacious manner to improve the VSWT system.