571 research outputs found
Study of the Crowbar's Functioning in Doubly Fed Induction Wind Generators: Towards Achieving Fault Ride Through Capability
No full textThis work examines the analysis of temporary behaviors and crowbar hardware layout for enhancing the fault ride-through capability (FRTC) in doubly fed induction wind generators (DFIWGs) A crowbar that is linked in parallel to the rotor side converter (RSC) is a feature found on the majority of DFIWGs these days to safeguard the RSC and DC-bus capacitor (DCBC). Previous studies demonstrated that the crowbar resistance has an impact on the DFIWG transient response's oscillations and peak values. In order to satisfy the FRTC criterion, the article initially methodically examines the DFIWG dynamics with and without a crowbar during a 100% voltage dip and studies the effects of two resistance values on the DCBC. It has been demonstrated that choosing a crowbar resistance greater than the permitted range may cause the DFIG FRT performance to decline. By actively addressing grid faults and improving performance, stability, and dependability, this integrated crowbar shows the potential of state-of-the-art control approaches for the dependable and efficient use of DFIWGs. MATLAB/Simulink is used to run robust simulations, and the results unambiguously show that the proposed model may significantly improve the FRTC of DFIWGs
Advanced control strategies of PMSM based wind energy conversion systems
No full textThesis (Ph.D.)-- Wichita State University, College of Engineering, Dept. of Electrical Engineering & Computer ScienceWind energy conversion system (WECS) is a system helps to produce the electrical energy
by transforming the incoming air stream. This system has two basic steps. First step is
the mechanical power which comes from the wind turbine blades. The second step is the
electrical power which produces by the generator. Due to complexity and dynamic variability
of electrical generator parameters, traditional control systems such as proportional-integraldeferential
(PID) controller has poor performance in case of fast dynamic response. With
WECS, the traditional control systems cause many controlling issues that affect WECS’s
efficiency and lead the system to have poor performance. Overshoot, undershoot, slow rising
time, and chattering are the consequences of applying the traditional control systems to
permanent magnet synchronous machine (PMSM). The main purpose of this dissertation
is to addresses this control issues and solves it which improve the PMSM’s performance
and WECS overall inefficiency. The dissertation proposes two advanced control strategies
that can enhance the electrical generator outcomes variables. Sliding mode control method
(SMC) and state dependent riccate equation control method (SDRE) have been derived,
designed,and applied to PMSM based WECS. The modeling results shows that both control
systems improved the generator dynamic response and limited the overshoot, undershoot,
and chattering effects. The simulation of the proposed models and results were simulated
using MATLAB Simulink software
Video interview with author and manuscript owner Professor Sa’adiya Omar
No full textFieldwork Team: Dr. Mustapha Hashim Kurfi (Principal Investigator), Hauwa Usman (Local Project Manager), Alhaji Abubakar Maikudi Aishat (General Field Facilitator). Technical Team: Prof. Fallou Ngom (Project Director and former Director of the African Studies Center), and Eleni Castrol (Technical Lead, BU Libraries). These collections on Gender in Nigerian Ajami Manuscripts are copied as part of the African Studies Center’s African Ajami Library. Access Condition and Copyright: These materials are subject to copyright. All rights reserved to the author. For use, distribution or reproduction contact Professor Fallou Ngom ([email protected]). Required Citation: Kurfi, M. H., Hauwa U., Ngom, F., and Castro, E. (2020). African Ajami Library: Gender in Nigerian Ajami Manuscripts. Boston: Boston University Libraries: http://hdl.handle.net/2144/41953. For Inquiries: Please Contact Professor Fallou Ngom ([email protected]).Video interview with author and manuscript owner Professor Sa’adiya Omar. Professor Sa’adiya Omar, the most celebrated author of women in the Sokoto Caliphate of Northern Nigeria. Professor Sa’adiya currently occupies the position of Nana Asma’u and Modibbo Kilo, the leaders of the Yantaru movement, i.e. Uwartaru (the Mother of the Yantaru). Equally, she had served as the National Amirah (President) of the largest Muslim umbrella organization in Nigeria – Federation of Muslim Women’s Associations in Nigeria (FOMWAN). As at the present, she serves in many capacities and is a member of various Islamic committees in Sokoto state and in Nigeria in general
STUDI PEMIKIRAN MUSTAFA AKYOL DAN HASHIM KAMALI TERHADAP PENERAPAN SANKSI APOSTASI: ANALISIS HERMENEUTIKA NEGOSIATIF
No full textThe death penalty for people who left from Islam is contrary to religious freedom. Human rights, which is the dominant discourse today, calls for a re-reading of the death penalty. The implication, there are many scholars who re-think the punishment of apostasy. Among them are Mustafa Akyol and Hashim Kamali who goes into this line. If the first name lives in the middle of a society where Muslims are a minority (America), then it is different from the last name. Hashim Kamali disseminated his ideas in Malaysia, one of the countries adhering to classical Islamic traditions. The fundamental question in this study is how the sanctions of apostasy are discussed again by the two thinkers.
This type of research is qualitative with future data on a library study (library research). These research data are derived from the representative works of Mustafa Akyol and Hashim Kamali on the subject of apostasy. Furthermore, the findings of their thinking are studied through the framework of negotiative hermeneutic theory. This theory was initiated by Khaled Abou El Fadl who pointed to the negotiations between the three entities, the author, the text and the reader. There are three key variables in discussing the thinking of Mustafa Akyol and Hashim Kamali. From texts and authority, the discourse of authoritarianism to the anatomy of the discourses of authority. Based on that, the approach taken here is socio-legal.
The first conclusion both Mustafa Akyol and Hashim Kamali have rejected the death penalty for apostasy. Second conclusion is using three variables when being analyzed by negotiative hermeneutic. In text and authority is able to be seen how a text is formed and its relationship with the social reality that surrounds it. The differences between the public who became the audience of them necessitate the differences in steps in the re-reading of this topic. On the discourse of authoritarianism can be reviewed the formation of non-authoritarian law by placing it as an entity that is constantly changing. Besides meeting the five prerequisites set by the hermeneutics of negotiations. In the anatomy of authoritarian discourse, there are three things that are discussed: consistency, a selective attitude to signs to the balance of interests and rationality. These two thinkers consistently use their respective steps in this topic. While Mustafa Akyol is selective to the sign, unlike Hashim Kamali. Despite this, they met at the same point with the conclusion that there is no death penalty for apostate perpetrators. This discussion is based on the success of both merging the importance of preserving religion and protecting human rights
Optimal Interior Mounted Permanent Magnet Synchronous Motors MTPA and MPPA Control Based on Sliding Mode Approaches
No full textClick on the DOI link to view this conference paper (may not be free).This paper presents novel sliding mode control (SMC) approaches for Maximum Torque Per Ampere (MTPA) and Maximum Power Per Ampere (MPPA) of interior permanent magnet synchronous motors (IPMs). We first derive the first-order sliding mode control methods to improve the field oriented control’s resiliency against the external perturbations, extraneous noise and modeling uncertainties. And after that, we propose the higher-order sliding mode control to significantly reduce the chattering phenomenon which is inherent in the first order sliding mode control method. Based on the comparison studies, the conventional proportional-integral derivative based field oriented control shows sluggish response and is more sensitive to parameter perturbations and external torque disturbances. By introducing the novel sliding mode control methods, both of the speed and torque regulation performance of interior-mounted permanent magnet synchronous motor can be greatly improved. Computer simulation studies have shown the superior performance of the first-order and higher-order sliding mode controllers for interior permanent magnet synchronous motor speed and torque regulation applications.ASM
Transient Stability Assessment of a Power System Using Multi-layer SVM Method
No full textClick on the URL link to access this conference paper on the publisher’s website (may not be free.)With the rapid growth of power systems, more large interconnections and the integration of large renewable energies make the systems more complicated. Therefore, transient stability assessment (TSA) has always been considered as one of the top challenges to ensure the security and operation of power systems. The development of Artificial Intelligence (AI) technologies, such as Artificial Neural Network (ANN) and Support Vector Machine (SVM) have been drawn attentions to the power industry recently. Compared with traditional SVM, this paper presents an advanced TSA system using Multi-layer Support Vector Machine (ML-SVM) method. Basically, a Genetic Algorithm (GA) is used in ML-SVM to identify the valued feature subsets with varying numbers of features which makes full use of the input information. Transient stabilities of the system are determined based on the generator relative rotor angles obtained from the time-domain simulation. Data from the time-domain simulation are used as the inputs for ML-SVM training and testing. Then these trained SVMs are integrated to assess the transient stability of the power system. The simulation results show that the proposed method can reduce the possibility of misclassification of the system. Case study of IEEE 9-bus system on PowerWorld Simulator illustrates the effectiveness of the proposed approach
A review on the effectiveness of change management in organization / Robeahtul Nabihah Anamallah and Nurhidayah Hashim.
No full textIn dealing with information is the crucial task in organization which can lead to the information leaking or wrong information. The process in sharing the knowledge during the transformation of work management also important because the change management are build a new and more effective work performance. Hence, change management is important for all organization. In the literature review study, the author highlighted the change management in organization which change leadership, the communication, and employee engagement and employee commitment. The literature review is significant to individual, organization, policy makers and knowledge worker
Video interview with author and manuscript owner Sheik Abdurrahman Aboki
No full textVideo interview with author and manuscript owner Sheikh Alhaji Abdurrahman Aboki. Sheikh Aboki is the Chief Imam of Central Mosque of the Federal Polytechnic, Bida—Niger State (Middle Belt of Nigeria) and the author of the manuscript in this collection titled "Ishriniyyah"
A Novel Sliding Mode Control Method of Interior-Mounted PMSM
No full textClick on the URL link to access this conference paper on the publisher’s website (may not be free.)Energy efficiency and output uncertainty are two of the most challenges that dynamic conversion is facing. Controlling the dynamic system variables is complicated due to the variability and unpredictability of the parameters, especially fast transient response. Sliding mode control is one effective technique that has been used to control and improve dynamic conversion system efficiency and to reach the rated values. Most of the recent research focus on the design, performance, and behaver study of sliding mode control in order to enhance the control system's performance. This paper presents a new Sliding mode control method of Interior-mounted permanent magnet synchronous motor. The proposed model solves many controlling problems that many other controllers facing such as PI controller, LQ regulator, and even PID linear methods. Also, the model has fast control response to the IPMSM fast dynamic transient and can solve the overshoot problem which leads the system to have more efficient performance. The results of SMC have been compared to PID controller applied to the same system. The simulation results have shown better performance of sliding mode control over the PID controller. The results are simulated using MATLAB Simulink software
Transient Stability Prediction Based on Long Short-term Memory Network
No full textClick on the DOI link to view this conference paper (may not be free).Transient stability assessment (TSA) has always been one of the most challenging problems in power system security and operations due to the rapid growth of electricity demand. The transient stability of power systems should be taken in advance to maintain the system stable. In recent years, a variety of Artificial Intelligence (AI) methods have been applied to the transient stability analysis, including Artificial Neural Network (ANN), Support Vector Machine (SVM) and some other technologies. In this paper, a transient stability prediction method using Long Short-term Memory (LSTM) network based Recurrent Neural Network (RNN) is discussed. Case studies using Multi-layer SVM on the IEEE 9 bus system is adopted as a benchmark to validate the proposed method. Then, the method is performed on the New-England 39 bus system to test the validity. The training and testing data of the LSTM network for the new approach are obtained by performing the time-domain simulation (TDS) on the New-England 39-Bus System in PSAT (Power System Analysis Toolbox) toolbox. Simulation results show that the proposed method exhibits significantly better classification accuracy on predicting the stability, which demonstrates the effectiveness of the proposed approach
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