Recent Advances in Electrical & Electronic Engineering - Volume 17, Issue 6, 2024

The transition from the first generation of technology, which only had an analog voice, to the fifth generation, which also had connected gadgets, gave the technology a new structure and changed how people used it. Fifth-generation wireless technology, often known as 5G, is on the cusp of reaching its potential maximum data transfer rate with a peak data throughput of 20 gigabits per second (Gbps) and a typical data transfer rate of more than 100 megabits per second (Mbps). The internet of things serves as the cornerstone of the future, and it is projected that by 2025, individual users will use 13 times the amount of data that we do at this time. Therefore, 5G is extremely important and the main feature of the 2030 Sustainable Development Agenda, which was ratified by all of the Member States of the United Nations in 2015, and is the 17 Sustainable Development Goals (SDGs), which represent an urgent call to action for all nations. These goals are referred to collectively as the "SDGs." This study intends to examine how 5G networks might serve as important facilitators for achieving sustainability and meeting some of the 17 SDGs. This is further highlighted by evaluating the sustainability metrics for 5G networks. Ultimately, this helps to demonstrate that 5G networks are environmentally, socially, and economically responsible. This study focuses on the five primary SDGs that are important for the growth of smart cities.

Background: DC-DC converters are used in various applications based on their required voltage capabilities ranging from milli volts to thousands of volts. Methods: This review paper discusses various voltage boosting techniques, such as buck-boost, switched inductor, switched capacitors, isolated converters, etc., and provides a detailed evaluation of the literature and comparison of different DC-DC converters. Results: This study reports a number of storage elements included, such as inductors and capacitors as well as switches and diodes. Their features along with methodologies, merits, complexity, efficiency, and voltage gain have been tabulated. A comprehensive study, converter classification based on the characteristics, and a detailed analysis of isolated and non-isolated DC-DC converters have also been provided. Conclusion: As this study provides a comparison of each isolated and non-isolated converter's comprehensive gain, this research may help in future topology optimization for the choice of the ideal converter for applications. In addition, the examination of each isolated and non-isolated converter's comprehensive gain comparison has also been presented in this paper.

Step-up DC-DC converters are employed to raise the output voltage level from the input voltage level. Although the basic boost dc-dc converter has advantages like simplicity of implementation, it also has drawbacks like low boost ability and low power density. The literature has reported various topologies which have switched inductor/voltage lift, switched capacitor, voltage multiplier, magnetic coupling, and multistage types. Each converter topology possesses its own advantages and disadvantages with a focus on power density, cost, efficiency, reliability, and complexity depending upon the applications. Demands of such applications are being fulfilled by using new power conversion topologies. Various combinations of such boosting topologies with additional components are complex. This paper provides a simple glance to the basic law and context for the development of future DC/DC converters. This paper has surveyed and classified various topologies according to the voltage-boosting topology and characteristics. The banes and boons of these topologies are also discussed in the paper with the applications of each boosting topology.

Introduction: Over the past few years, researchers have greatly focused on increasing the electrical efficiency of large computer systems. Virtual machine (VM) migration helps data centers keep their pages' content updated on a regular basis, which speeds up the time it takes to access data. Offline VM migration is best accomplished by sharing memory without requiring any downtime. Objective: The objective of the paper was to reduce energy consumption and deploy a unique green computing architecture. The proposed virtual machine is transferred from one host to another through dynamic mobility. Methodology: The proposed technique migrates the maximally loaded virtual machine to the least loaded active node, while maintaining the performance and energy efficiency of the data centers. Taking into account the cloud environment, the use of electricity could continue to be critical. These large uses of electricity by the internet information facilities that maintain computing capacity are becoming another major concern. Another way to reduce resource use is to relocate the VM. Results: Using a non-linear forecasting approach, the research presents improved decentralized virtual machine migration (IDVMM) that could mitigate electricity consumption in cloud information warehouses. It minimizes violations of support agreements in a relatively small number of all displaced cases and improves the efficiency of resources. Conclusion: The proposed approach further develops two thresholds to divide overloaded hosts into massively overloaded hosts, moderately overloaded hosts, and lightly overloaded hosts. The migration decision of VMs in all stages pursues the goal of reducing the energy consumption of the network during the migration process. Given ten months of data, actual demand tracing is done through PlanetLab and then assessed using a cloud service.

Background: The implementation of Battery Energy Storage Systems (BESSs) and carbon capture units can effectively reduce the total carbon emissions of distribution networks. However, their widespread adoption has been hindered by the high investment costs associated with the BESSs and power generation costs of carbon capture units. Objective: The objective of this paper is to optimize the location and sizing of BESSs in distribution networks that comprise renewable power plants and coal-fired power units with carbon capture systems. The optimization process aims to minimize the grid’s impact from the configuration while maximizing economic cost savings and the benefits of reducing carbon emissions. Methods: A bi-layer optimization model is proposed to determine the configuration of BESSs. The upper layer of the model optimizes the size and operation strategy of the BESSs to minimize the configuration and power generation costs, using YALMIP and CPLEX optimization tools. Carbon emission reduction benefits are considered through deep peak-shaving and carbon tax. The lower layer of the model aims to optimizes the placement of the BESSs to minimize voltage fluctuation and network loss in the power grid. To achieve this, we improved the efficiency of the Nondominated Sorting Genetic Algorithm II (NSGA-II) to update the BESS’s placement. Results: The IEEE33-bus and IEEE118-bus systems were utilized for simulation and comparison in various scenarios. The findings demonstrate that the proposed configuration method can decrease the cost of investment and power generation. Furthermore, it reduces the degree of node voltage fluctuation and network loss in the distribution network. Conclusion: The study reveals that determining the optimal scale of BESSs can mitigate high energy consumption in carbon capture systems and improve the overall performance of power systems that integrate carbon capture technology and renewable power plants.

Background: The double-end H-bridge inverters can realize independent control of the stator voltage in each phase and have flexible advantages of modulation and fault tolerance; thus, they are more suitable for multi-phase fault-tolerant motor drives. However, due to the increase of voltage vectors and the coupling between the electromagnetic and non-electromagnetic quantities, the normal control strategies for traditional three-phase motor drives do not work anymore. Objective: This paper aimed to propose a simplified model predictive current control strategy based on the vector space decomposition (VSD) and the vectors’ gradual simplification for the three-level six-phase H-bridge inverters. Methods: Firstly, the 729 physical variables were decomposed and mapped onto the fundamental αβ subspace, harmonic xy subspace, and the zero-sequence o1o2 subspace based on the VSD. Then, to eliminate the influence of the harmonic and zero-sequence components on the control performance and make an easy digital implementation, vectors’ simplification has been proposed based on the in-depth analysis of the relationship between the voltage vectors mapped onto different subspaces and vectors’ stratification. With the simplification method, the number of voltage vectors was simplified from 729 to 12, and then the selected voltage vectors were used in the rolling optimization of the model predictive current control (MPCC) to choose the optimal one. Finally, sufficient experiments were carried out including static and dynamic conditions, different modulation index and power factor, etc., to verify the feasibility of the proposed strategy. Results: The simulation and experimental results show that with the simplified MPCC strategy, both the static and dynamic performances are relatively good, and the THDs of the phase current under different modulations and power factors are relatively low. Conclusion: The proposed MPCC algorithm for the three-level six-phase H-bridge inverters has shown obvious improvement in solving the control problems of multi-vectors and complex redundancy issues.

Background: It gives out the design and verification of single-layer dual-band antenna unit and multi-layer dual-band broadband antenna unit of phased array antenna, and verifies that the multi-layer dual-band broadband antenna unit can meet the design requirements of the receiving frequency band. Objective: It gives out the design and implementation of a wide-band circularly polarized conformal antenna, and presents the characteristics analysis of the antenna. Methods: Through related simulation methods, the proposed methods are verified and they can effectively solve the array phase compensation and beam shaping and control in the wide-band circularly polarized conformal antenna. Results: Based on the basic design of the antenna, the active superposition algorithm, phase compensation technology and particle swarm optimization antenna beam shaping technology are both studied. Conclusion: The proposed wide-band circularly polarized conformal antenna can be used in the actual application.