A framework to characterize energy efficiency measures

Observing present scarcity of fossil fuel and emissions of greenhouse gases, electricity generated from Renewable Energy (RE) sources turns out to be the best alternative for generating the power. In RE system, the inverter is normally used to condition the DC power into AC to meet the requirements of load and transmission system. The inverter offers myriad benefits; however, the presence of harmonics (particularly low-order) in the output voltage affects the efficiency and performance of inverter, causes switching losses and decreases the lifetime of the system. In last three decades, significant research has been done to develop the efficient control technique for eliminating the unwanted harmonics. The preliminary review of existing control techniques revealed that the selective harmonic elimination pulse-width modulation (SHEPWM) is more proficient to eliminate the low-order harmonics. However, non-linear transcendental equations used in this technique pose a challenge to solve particularly for calculus-based methods. With the advent of powerful and low-cost computers, bio-inspired intelligent algorithms (BIAs) seem to be a better approach for solving these complex equations. This review paper presents the detailed principle operation of nine well-known BIAs and discusses their application in inverters for harmonic elimination (HE). Moreover, different objective functions are also discussed in this paper which is used by the researchers for HE. Additionally, the performance of five renowned BIAs, namely, Imperialist Competitive Algorithm, Particle Swarm Optimization, Differential Evolution, Bee Algorithm and Genetic Algorithm is critically evaluated. Their performance is analyzed in terms of accuracy, computational complexity, convergence speed, and a number of control parameters. The conclusion has been made on the basis of information extracted from the literature and evaluation results with future recommendations. This single paper covers all the essential information regarding HE in inverters, which will help researchers to design the efficient RE conversion system.

Selective harmonic elimination in inverters using bio-inspired intelligent algorithms for renewable energy conversion applications: A review

The imbalance between energy supply and demand is expected to keep increasing, with the manufacturing sector being responsible for about one-third of world energy consumption Hence, concerns about energy-efficient and environmentally benign manufacturing process have become an emerging issue This paper suggests a novel hierarchy of energy saving technologies for machine tools, mainly for machining Cutting is a widely used traditional process, and accounts for a large portion of energy consumption in machine tool sectors A novel hierarchy is suggested, from the perspective of a single device manager, in accordance with the level of application Technologies and strategies were compiled from research project reports, journal and conference articles, energy policies, etc  They were then rearranged in respective levels in the suggested hierarchy Theories and technologies in the assessment and modeling of energy characteristics were reviewed, and general strategies on micro process planning were discussed at the software-based optimization level Then, technologies for control and cutting improvement, such as novel lubrication and assisted machining systems, were introduced, and their effects were presented Finally, improvement of hardware components and design rules for the environment were reviewed Future market demands have clearly drawn more attention to energy efficiency, and the energy consumption of machine tools should be more accurately modeled and controlled Loss and unnecessary operation of partial components should be minimized From the perspective of energy efficiency, machine tools are expected to become more compact and lightweight Operators and manufacturers need to understand both the process and hardware for greener machine tools

Towards greener machine tools – A review on energy saving strategies and technologies

Solar energy is one of the cleanest sources of alternative energy. Due to high energy demand in one hand and environmental negative impact of fossil fuels, on the other hand, many countries consider the alternative energy sources as a suitable and feasible option in industry and domestic usage. It was discovered that the different applications of solar energy in industries are being accepted more than ever. The present study is a state of art on the numerous new and feasible technologies of solar energy applications in the agricultural sectors. It discusses about the importance of solar energy as environmental clean technologies and the most reliable energy source. This study covers different types of solar energy systems like as solar photovoltaic and solar thermal for pumping water, drying crops, cooling the storages and producing heating/cooling greenhouses. It has been proven that photovoltaic systems and/or solar thermal system would be the suitable options in agricultural application and especially for the distant rural area.

The application of solar technologies for sustainable development of agricultural sector

Induction motor (IM) drives, specifically the three-phase IMs, are a nonlinear system that are difficult to explain theoretically because of their sudden changes in load or speed conditions. Thus, an advanced controller is needed to enhance IM performance. Among numerous control techniques, fuzzy logic controller (FLC) has increasing popularity in designing complex IM control system due to their simplicity and adaptability. However, the performance of FLCs depends on rules and membership functions (MFs), which are determined by a trial-and-error procedure. The main objective of this paper is to present a critical review on the control and optimization techniques for solving the problems and enhancing the performance of IM drives. A detailed study on the control of variable speed drive, such as scalar and vector, is investigated. The scalar control functions of speed and V/f control are explained in an open- and closed-loop IM drive. The operation, advantages, and limitations of the direct and indirect field-oriented controls of vector control are also demonstrated in controlling the IM drive. A comprehensive review of the different types of optimization techniques for IM drive applications is highlighted. The rigorous review indicates that existing optimization algorithms in conventional controller and FLC can be used for IM drive. However, some problems still exist in achieving the best MF and suitable parameters for IM drive control. The objective of this review also highlights several factors, challenges, and problems of the conventional controller and FLC of the IM drive. Accordingly, the review provides some suggestions on the optimized control for the research and development of future IM drives. All the highlighted insights and recommendations of this review will hopefully lead to increasing efforts toward the development of advanced IM drive controllers for future applications.

Optimization techniques to enhance the performance of induction motor drives: A review

Most motors are designed to operate at a constant speed and provide a constant output; however, modern technology requires different speeds in many applications where electric motors are used. A variable speed drive (VSD) is a device that regulates the speed and rotational force, or output torque of mechanical equipment. Effects of applying VSDs are in both productivity improvements and energy savings in pumps, fans, compressors and other equipment. Variable speed drive technology and the importance of controlling the speed of existing motors have fascinated many attentions in the last years with the advent of new power devices and magnetic materials. This paper is a comprehensive review on applications of VSD in electrical motors energy savings. The aim is to identify energy saving opportunities and incorporated costs of applying variable speed drives to the existing applications of electrical motors. Subsequently, economic analysis, payback period and the effect of current and voltage harmonics generated by VSDs are presented. Authors are hopeful to provide useful information for future variable speed drive applications like fans, pumps, chillers, ventilators and heaters.

Mansouri B. Ali

Papers

Applications of variable speed drive (VSD) in electrical motors energy savings