Dynamic Modeling and Control of DFIG for Wind Energy Conversion System Using Feedback Linearization

Ghulam Sarwar Kaloi,Jie Wang,Mazhar Hussain Baloch 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.5

This paper presents a dynamic modeling and control of doubly fed induction-generator (DFIG) based variable speed wind-turbine. The dynamic model of DFIG is incorporated with all system components which provide simple design and controls. The penetration of wind power is increasing into electrical networks, which necessitates more comprehensive studies to recognize the interaction between the wind farms and the power grid. This paper presents the dynamic model of a DFIG based wind turbine connected to the grid system in the dq-synchronous reference frame. In this article, the feedback linearization method has proposed a controller in order to reduce the oscillation and stabilize the wind turbine system parameters based on feedback linearization concepts. Based on the nonlinear control system, the proposed approach is applied to the rotor side converter and grid side converter. The damping of the DFIG is improved in transient response. In addition, the oscillation of the stator current and DC link voltage during the generator voltage dip are reduced. To the best of author’s knowledge, the proposed control outcomes compared with conventional controller verified the effectiveness, having better performance through simulation tool Matlab.

Effect of Compost and Gypsum Application on the Chemical Properties and Fertility Status of Saline-Sodic Soil

Sarwar, Ghulam,Ibrahim, Muhammad,Tahir, Mukkram Ali,Iftikhar, Yasir,Haider, Muhammad Sajjad,Noor-Us-Sabah, Noor-Us-Sabah,Han, Kyung-Hwa,Ha, Sang-Keun,Zhang, Yong-Seon Korean Society of Soil Science and Fertilizer 2011 한국토양비료학회지 Vol.44 No.3

Salt-affected soils are present in Pakistan in significant quantity. This experiment was conducted to assess the effectiveness of compost for reclamation and compare its efficiency with gypsum. For this purpose, various combinations of compost and gypsum were used to evaluate their efficacy for reclamation. A saline-sodic field having $pH_s$ 8.90, $EC_e$ $5.94dS\;m^{-1}$ and SAR $34.5(mmol\;L^{-1})^{1/2}$, SP (saturation percentage) 42.29% and texture Sandy clay loam, gypsum requirement (GR) $8.75Mg\;ha^{-1}$ was selected for this study. The experiment comprised of seven treatments (control, gypsum alone, compost alone and different combinations of compost and gypsum based on soil gypsum requirements). Inorganic and organic amendments (gypsum and compost) were applied to a saline sodic soil. Rice and wheat crops were grown. Soil samples were collected from each treatment after the harvest of both crops and analyzed for chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) and fertility status (organic matter, available phosphorus and potassium contents) of soil. Results of this study revealed that compost and gypsum improved chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) of saline sodic soil to the desired levels. Similarly, all parameters of soil fertility like organic matter, available phosphorus and potassium contents were built up with the application of compost and gypsum.

Effect of Compost and Gypsum Application on the Chemical Properties and Fertility Status of Saline-Sodic Soil

Ghulam Sarwar,Muhammad Ibrahim,Mukkram Ali Tahir,Yasir Iftikhar,Muhammad Sajjad Haider,Noor-us-Sabah,한경화,하상건,장용선 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.3

Salt-affected soils are present in Pakistan in significant quantity. This experiment was conducted to assess the effectiveness of compost for reclamation and compare its efficiency with gypsum. For this purpose,various combinations of compost and gypsum were used to evaluate their efficacy for reclamation. A saline-sodic field having pHs 8.90, ECe 5.94 dS m^–1 and SAR 34.5 (mmol L^–1)^1/2, SP (saturation percentage)42.29% and texture Sandy clay loam, gypsum requirement (GR) 8.75 Mg ha^–1 was selected for this study. The experiment comprised of seven treatments (control, gypsum alone, compost alone and different combinations of compost and gypsum based on soil gypsum requirements). Inorganic and organic amendments (gypsum and compost) were applied to a saline sodic soil. Rice and wheat crops were grown. Soil samples were collected from each treatment after the harvest of both crops and analyzed for chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) and fertility status (organic matter,available phosphorus and potassium contents) of soil. Results of this study revealed that compost and gypsum improved chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) of saline sodic soil to the desired levels. Similarly, all parameters of soil fertility like organic matter, available phosphorus and potassium contents were built up with the application of compost and gypsum.

Dynamic Modeling and Control of DFIG for Wind Energy Conversion System Using Feedback Linearization

Kaloi, Ghulam Sarwar,Wang, Jie,Baloch, Mazhar Hussain The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.5

N-스크린 기반 인터렉티브 멀티 비전 시스템 제어 구조

굴람 사와(Ghulam Sarwar),파만 울라(Farman Ullah),윤장우(Changwoo Yoon),이성창(Sungchang Lee) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.6

본 논문에서는 기존 Multi-Vision System(MVS)에서 지원되지 않았던 N-스크린 서비스를 구현하기 위한 시스템 구조와 시스템과 사용자간의 인터랙션 방안을 제안한다. MVS의 N-스크린 서비스는 사용자가 다양한 단말들을 사용하여 자유로운 위치에서 MVS 디스플레이를 제어하고 MVS의 컨텐츠를 연속성 있게 공유할 수 있게 한다. 본 논문에서는 MVS에서 N-Screen Service 의 인터랙션 서비스를 지원하기 위해 관리 서버와 에이젼트를 도입한 서비스 방안을 제안한다. 그리고, 어플리케이션 실행, 서비스 제어를 위한 사용자 인터렉션 그리고 N-스크린 서비스를 지원하기 위한 비주얼 캐스팅 등을 위한 몇 가지 프로토콜의 예를 제시한다. 추가적으로, N-스크린 세션 분할, 그리고, 위치에 구애 받음 없이 사용 중인 사용자의 다양한 단말을 사용한 메타데이타 컨텐츠 실행 등을 위한 프로토콜을 사용한 N-스크린 서비스 시나리오도 예로서 기술한다. 시뮬레이션 결과는 제안 된 메커니즘의 적합성과 성능개선을 보여준다. In this paper, we propose the architecture and user interaction mechanism to implement N-Screen services on Multi-Vision System (MVS) that are not supported in existing systems. N-Screen services enable users to control the MVS displays through any of their devices and share contents among MVS displays and user’s active-devices with service continuation at any location. We provide N-Screen interactive services on MVS by introducing N-Screen interaction & session management server and agent. Furthermore, we present some examples of the protocols such as application launching, user interaction for service control and visualcasting to support N-Screen services. In addition, we explain the N-Screen service scenarios for providing split sessions on user’s active-devices and launching metadata content on any of his devices at any location supported by these protocols. The simulation result demonstrates the feasibility and performance improvement of the proposed visualcasting mechanisms.

시간 정보를 이용한 확장성 있는 하이브리드 Recommender 시스템

Farman Ullah,Ghulam Sarwar,김재우,문경덕,김진태,이성창 한국인터넷방송통신학회 2012 한국인터넷방송통신학회 논문지 Vol.12 No.2

최근 디지털 컨텐츠와 컨텐츠 사용자의 기하 급수적인 증가와 함께 recommender 시스템이 주목을 받으며 많은 응용 프로그램에 적용되고 있는 가운데, recommender 시스템의 확장성과 대체적으로 이와 반비례하는 정확성이 이슈가 되고 있다. 본 논문에서는 recommender 시스템 모델 중 하이브리드 모델의 매트릭스를 제거하고 아이템의 특성을 정하기 위해 클러스터링 기술을 사용한 Scalable Hybrid Recommender System을 제안한다. 제안된 모델은 recommender 시스템의 확장성과 정확성을 향상시키기 위해서 아이템에 대한 사용자의 평가 정보, demographic 정보와 구체적인 시간 정보를 사용한다. Reduction 기술 사용을 통해 Item-feature 매트릭스의 사이즈를 축소하고, 사용자 demographic 정보를 사용하여 temporal aware hybrid user model을 만든 후, 비슷한 정보를 가진 사용자간 클러스터링을 통해, 가장 유사한 정보를 가진 사용자들을 추출하여, 사용자간 정보를 비교함으로써 사용자가 원하는 아이템의 특성을 예상하고 사용자에게 N개의 아이템을 추천함으로써, 기존의 recommender 시스템보다 더욱 향상된 결과를 도출해 낼 수 있는 알고리즘을 제시하였다. Recommender Systems have gained much popularity among researchers and is applied in a number of applications. The exponential growth of users and products poses some key challenges for recommender systems. Recommender Systems mostly suffer from scalability and accuracy. The accuracy of Recommender system is somehow inversely proportional to its scalability. In this paper we proposed a Context Aware Hybrid Recommender System using matrix reduction for Hybrid model and clustering technique for predication of item features. In our approach we used user item-feature rating, User Demographic information and context information i.e. specific time and day to improve scalability and accuracy. Our Algorithm produce better results because we reduce the dimension of items features matrix by using different reduction techniques and use user demographic information, construct context aware hybrid user model, cluster the similar user offline, find the nearest neighbors, predict the item features and recommend the Top N- items.

Hybrid Recommender System for Movies Using Device Information

Farman Ullah,Ghulam Sarwar,Kim Jae Woo(김재우),Park Yun Kyung(박윤경),Moon Kyeong Deok(문경덕),Lee Sung Chang(이성창) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.2

A Network and Visual Quality Aware N-Screen Content Recommender System Using Joint Matrix Factorization

Ullah, Farman,Sarwar, Ghulam,Lee, Sungchang Hindawi Publishing Corporation 2014 The Scientific World Journal Vol.2014 No.-

<P>We propose a network and visual quality aware N-Screen content recommender system. N-Screen provides more ways than ever before to access multimedia content through multiple devices and heterogeneous access networks. The heterogeneity of devices and access networks present new questions of QoS (quality of service) in the realm of user experience with content. We propose, a recommender system that ensures a better visual quality on user's N-screen devices and the efficient utilization of available access network bandwidth with user preferences. The proposed system estimates the available bandwidth and visual quality on users N-Screen devices and integrates it with users preferences and contents genre information to personalize his N-Screen content. The objective is to recommend content that the user's N-Screen device and access network are capable of displaying and streaming with the user preferences that have not been supported in existing systems. Furthermore, we suggest a joint matrix factorization approach to jointly factorize the users rating matrix with the users N-Screen device similarity and program genres similarity. Finally, the experimental results show that we also enhance the prediction and recommendation accuracy, sparsity, and cold start issues.</P>

An Optimal Asset Allocation Strategy for Suppliers Paying Carbon Tax in the Competitive Electricity Market

Waqas Ahmad Wattoo,Ghulam Sarwar Kaloi,Muhammad Yousif,Mazhar Hussain Baloch,Baqar Ali Zardar,Jehangir Arshad,Ghulam Farid,Talha Younas,Sohaib Tahir 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

The escalating energy demand across the globe has intensifed the electricity production. Owing to the unavailability of the reliable techniques for electricity storage for a long duration, it is consumed immediately after its production. Therefore, electricity markets can’t be handled like the conventional stock markets. Power companies are facing immense price and delivery risks owing to the increasing competition in the electricity markets. As a result, risk management is the fundamental concern to be addressed in order to achieve the optimum proft targets. Consequently, the power generation organizations need to allocate their generation in bilateral contracts and spot market. For this purpose, an optimal theory of portfolio selection is proposed in this study for electricity generation by forming a reliable prototype and applying the proposed scheme to obtain the suitable outcomes. The Paris Accord on environmental safety from carbon dioxide and NOx gases is especially considered during the modeling of the proposed technique. The credibility of the proposed scheme is validated by using the real-time market data from the PJM market. Various risk-return tradeofs are implemented, and their corresponding solutions are acquired for portfolio optimization as corroborated by the results. The suggested technique is found reliable and adequate for the carbon tax paying suppliers around the world for allocating their respective generation based on the demand of the consumers.

Rate of Farm Manure Decomposition Applied alone and in Combination with Dap and Release of P in Different Soils

Fakhar Mujeeb,Muhammad Ibrahim,Ghulam Sarwar,Muhammad Adrees 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6