Optimal load dispatch of community microgrid with deep learning based solar power and load forecasting

Slope stability prediction using integrated metaheuristic and machine learning approaches: A comparative study

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

Detailed study, multi-objective optimization, and design of an AC-DC smart microgrid with hybrid renewable energy resources

This paper elaborates a comprehensive overview of a photovoltaic (PV) system model, and compares the attributes of various conventional and improved incremental conductance algorithms, perturbation and observation techniques, and other maximum power point tracking (MPPT) algorithms in normal and partial shading conditions Performance evaluation techniques are discussed on the basis of the dynamic parameters of the PV system Following a discussion of the MPPT algorithms in each category, a table is drawn to summarize their key specifications In the performance evaluation section, the appropriate PV module technologies, atmospheric effects on PV panels, design complexity, and number of sensors and internal parameters of the PV system are outlined In the last phase, a comparative table presents performance-evaluating parameters of MPPT design criterion This paper is organized in such a way that future researchers and engineers can select an appropriate MPPT scheme without complication

Performance Evaluation of Maximum Power Point Tracking Approaches and Photovoltaic Systems

For a reliable dynamic system and significant amount of savings in energy usage, adjustable speed drives (ASD) can play a vital role. The proper control of motor drives can give a good system response and also increase the efficacy of the drive. Recently the direct torque control (DTC) strategy has drawn great attention for motor drives due to its simplicity, insensitivity to the motor parameters, high reliability and improved dynamic response. Many control strategies have been developed for the improvement of conventional DTC drives focusing specifically on torque and flux. A number of techniques have been formulated and successfully implemented for induction motor (IM) control. This paper aims to provide a substantial updated review, albeit by no means complete, for those who are interested in keeping track of the present state-of-the-art in this field and working further. The review focuses on different control algorithms of DTC IM drives and their applications to minimize the energy losses and improve the system efficacy.

A review of reliable and energy efficient direct torque controlled induction motor drives

A rotational d–q current control scheme is prepared with the particle swarm optimization-PI controller, which drives an induction motor through an ultra-sparse Z -source matrix converter. To minimize the total size of the system, the lowest feasible values of Z -source elements are calculated by considering both timing and circuit aspects. A meta-heuristic method is integrated with the control system in order to find the optimum coefficients values in a single multimodal problem. Henceforth, the effect of all coefficients in minimizing the THD and balancing the stator current are considered simultaneously. By changing the reference point of magnitude or frequency, the modulation index can be automatically adjusted and respond to changes without heavy computational cost. The focus of this research is on having a reliable and lightweight system with no extensive computing time demand. The proposed scheme is validated by the promising simulation and experimental results.

A PSO-DQ Current Control Scheme for Performance Enhancement of Z-Source Matrix Converter to Drive IM Fed by Abnormal Voltage

Ag-IoT for crop and environment monitoring: Past, present, and future

This paper aims to improve the performance of conventional direct torque control (DTC) drives proposed by Takahashi by extending the idea for 5-level inverter. Hybrid cascaded H-bridge topology is used to achieve inverter voltage vector composed of 5-level of voltage. Although DTC is very popular for its simplicity but it suffers from some disadvantages like- high torque ripple and uncontrollable switching frequency. To compensate these shortcomings conventional DTC strategy is modified for five levels voltage source inverter (VSI). Multilevel hysteresis controller for both flux and torque is used. Optimal voltage vector selection from precise lookup table utilizing 12 sector, 9 torque level and 4 flux level is proposed to improve DTC performance. These voltage references are produced utilizing a hybrid cascaded H-bridge multilevel inverter, where inverter each phase can be realized using multiple dc source. Fuel cells, car batteries or ultra-capacitor are normally the choice of required dc source. Simulation results shows that the DTC drive performance is considerably improved in terms of lower torque and flux ripple and less THD. These have been experimentally evaluated and compared with the basic DTC developed by Takahashi.

https://www.koreascience.kr:443/article/JAKO201509057413829.pdf

Modeling and experimental validation of 5-level hybrid H-bridge multilevel inverter fed DTC-IM drive

Speaking English is a part of the daily academic life of the EFL learners at the undergraduate level of the major English programs in Bangladesh. This practice sometimes creates many problems for first-year undergraduate public and private university students. Despite its importance, sufficient data about the problems Bangladeshi university students face in speaking English was not found. To investigate the problems of speaking faced by the undergraduate students, the current study applied mixed methods, and eighty-eight students and four teachers from four universities participated in it. The result shows that both public and private university students with English majors face a lot of problems communicating in English. However, this study has found that public university students are slightly more competent in English and face fewer problems than private university students. The participants expressed different insights on the roles of curriculum, teaching techniques, and individual institutions to overcome the students' weakness in English speaking skills. Finally, the study puts forward some very specific recommendations on the basis of the findings for the concerned stakeholders.

Md. Didarul Islam

Papers

A review of reliable and energy efficient direct torque controlled induction motor drives

A PSO-DQ Current Control Scheme for Performance Enhancement of Z-Source Matrix Converter to Drive IM Fed by Abnormal Voltage

Ag-IoT for crop and environment monitoring: Past, present, and future

Modeling and experimental validation of 5-level hybrid H-bridge multilevel inverter fed DTC-IM drive

Investigating the Problems Faced by the University EFL Learners in Speaking English Language