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Mohammad Tavakoli Bina

Bio: Mohammad Tavakoli Bina is an academic researcher from K.N.Toosi University of Technology. The author has contributed to research in topics: AC power & Converters. The author has an hindex of 17, co-authored 90 publications receiving 1210 citations. Previous affiliations of Mohammad Tavakoli Bina include University of Surrey & Shahid Beheshti University of Medical Sciences and Health Services.


Papers
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Journal ArticleDOI
TL;DR: In this article, a new transformerless four-leg topology is proposed for shunt compensation, the modular multilevel converters (MMC) based on the half-bridge converters, to achieve higher performance as a STATCOM in a distorted and unbalanced medium-voltage large-current (MV-LC) system.
Abstract: A new transformerless four-leg topology is suggested for shunt compensation, the modular multilevel converters (MMC) based on the half-bridge converters, to achieve higher performance as a STATCOM in a distorted and unbalanced medium-voltage large-current (MV-LC) system. Further, an extended MMC (EMMC) is proposed in order to manage more accurate compensation for high-power applications. Both proposals can be controlled for various purposes such as reactive power and unbalance compensation, voltage regulation, and harmonic cancellation. Moreover, related control strategies are also suggested for both the MMC and the EMMC to ensure that the source-end three-phase currents are sinusoidal and balanced. Also, the dc-link capacitors of the half-bridge converters are regulated. One interesting application for the EMMC-based STATCOM could be the improvement in power quality and performance of the electrified railway traction power supply system. Both the MMC- and the EMMC-based STATCOM along with their proposed control strategies were simulated; further, to verify the suggestions, these proposals were also implemented on a 30-kVA modular laboratory prototype. Experiments and simulations confirm the predefined objectives.

353 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a method in expansion planning of transmission systems using the AC optimal power flow (AC-OPF), which provides a more accurate picture of power flow in the network compared to the DC optimal power flows (DC-OPFs) that is usually considered in the literature for transmission expansion planning.

88 citations

Journal ArticleDOI
TL;DR: In this paper, a linear approximated methodology for full alternating current-optimal power flow (AC-OPF) is presented, which can provide more precise and real picture of full active and reactive power flow modelling, along with the voltage profile of buses compared to the commonly used direct current-optimality power flow.
Abstract: This study presents a novel linear approximated methodology for full alternating current-optimal power flow (AC-OPF). The AC-OPF can provide more precise and real picture of full active and reactive power flow modelling, along with the voltage profile of buses compared to the commonly used direct current-optimal power flow. While the AC-OPF is a non-linear programming problem, this can be transformed into a mixed-integer linear programming environment by the proposed model without loss of accuracy. The global optimality of the solution for the approximated model can be guaranteed by existing algorithms and software. The numerical results and simulations which represent the effectiveness and applicability of the proposed model are given and completely discussed in this study.

79 citations

Journal ArticleDOI
TL;DR: In this article, the analysis and practice of power losses in a three-level neutral-point clamped (NPC) inverter is presented. And the lifetime of semiconductors is predicted using the heating curves in line with the power-cycling concept.
Abstract: Multilevel converters are growing fast, whereas industry needs particular tools to evaluate efficiency and performance of such converters. This study focuses on the analysis and practice of power losses in a three-level neutral-point clamped (NPC) inverter. First, a precise mathematical model for three-level inverters is introduced to be used for simulating power losses of the switches, providing AC voltage and current of each phase, voltage and current of the switches as well as both the conduction and switching losses. Further, an NPC inverter was developed to validate the analytical work by comparing experimental results with those of simulations. Additionally, the thermal modelling of semiconductors is obtained using datasheet parameters. Then, the temperature rise is further modelled using the power losses along with the thermal model in the form of RC ladder. Finally, the lifetime of semiconductors is predicted using the heating curves in line with the power-cycling concept. The measured power losses and temperatures in comparison with the presented model suggest this kind of research as an applicable replacement for expensive measuring devices.

70 citations

Journal ArticleDOI
TL;DR: Optimal placement of parallel and series FACTS devices is studied and an index based on objective function value is presented to determine the optimal number of each FACTS device in a specific designed algorithm.

68 citations


Cited by
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01 Jun 2005

3,154 citations

Journal ArticleDOI
TL;DR: A general overview of the basics of operation of the MMC along with its control challenges are discussed, and a review of state-of-the-art control strategies and trends is presented as mentioned in this paper.
Abstract: The modular multilevel converter (MMC) has been a subject of increasing importance for medium/high-power energy conversion systems. Over the past few years, significant research has been done to address the technical challenges associated with the operation and control of the MMC. In this paper, a general overview of the basics of operation of the MMC along with its control challenges are discussed, and a review of state-of-the-art control strategies and trends is presented. Finally, the applications of the MMC and their challenges are highlighted.

1,765 citations

01 Jan 1979
TL;DR: This special issue aims at gathering the recent advances in learning with shared information methods and their applications in computer vision and multimedia analysis and addressing interesting real-world computer Vision and multimedia applications.
Abstract: In the real world, a realistic setting for computer vision or multimedia recognition problems is that we have some classes containing lots of training data and many classes contain a small amount of training data. Therefore, how to use frequent classes to help learning rare classes for which it is harder to collect the training data is an open question. Learning with Shared Information is an emerging topic in machine learning, computer vision and multimedia analysis. There are different level of components that can be shared during concept modeling and machine learning stages, such as sharing generic object parts, sharing attributes, sharing transformations, sharing regularization parameters and sharing training examples, etc. Regarding the specific methods, multi-task learning, transfer learning and deep learning can be seen as using different strategies to share information. These learning with shared information methods are very effective in solving real-world large-scale problems. This special issue aims at gathering the recent advances in learning with shared information methods and their applications in computer vision and multimedia analysis. Both state-of-the-art works, as well as literature reviews, are welcome for submission. Papers addressing interesting real-world computer vision and multimedia applications are especially encouraged. Topics of interest include, but are not limited to: • Multi-task learning or transfer learning for large-scale computer vision and multimedia analysis • Deep learning for large-scale computer vision and multimedia analysis • Multi-modal approach for large-scale computer vision and multimedia analysis • Different sharing strategies, e.g., sharing generic object parts, sharing attributes, sharing transformations, sharing regularization parameters and sharing training examples, • Real-world computer vision and multimedia applications based on learning with shared information, e.g., event detection, object recognition, object detection, action recognition, human head pose estimation, object tracking, location-based services, semantic indexing. • New datasets and metrics to evaluate the benefit of the proposed sharing ability for the specific computer vision or multimedia problem. • Survey papers regarding the topic of learning with shared information. Authors who are unsure whether their planned submission is in scope may contact the guest editors prior to the submission deadline with an abstract, in order to receive feedback.

1,758 citations

01 Jan 2015
TL;DR: This compact, informal introduction for graduate students and advanced undergraduates presents the current state-of-the-art filtering and smoothing methods in a unified Bayesian framework and learns what non-linear Kalman filters and particle filters are, how they are related, and their relative advantages and disadvantages.
Abstract: Filtering and smoothing methods are used to produce an accurate estimate of the state of a time-varying system based on multiple observational inputs (data). Interest in these methods has exploded in recent years, with numerous applications emerging in fields such as navigation, aerospace engineering, telecommunications, and medicine. This compact, informal introduction for graduate students and advanced undergraduates presents the current state-of-the-art filtering and smoothing methods in a unified Bayesian framework. Readers learn what non-linear Kalman filters and particle filters are, how they are related, and their relative advantages and disadvantages. They also discover how state-of-the-art Bayesian parameter estimation methods can be combined with state-of-the-art filtering and smoothing algorithms. The book’s practical and algorithmic approach assumes only modest mathematical prerequisites. Examples include MATLAB computations, and the numerous end-of-chapter exercises include computational assignments. MATLAB/GNU Octave source code is available for download at www.cambridge.org/sarkka, promoting hands-on work with the methods.

1,102 citations

Journal ArticleDOI
TL;DR: In this article, the authors present an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters, and a number of practical examples are demonstrated to illustrate the feasibility of virtual impedances.
Abstract: The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models. Different virtual impedances and their implementation issues are then discussed. A number of practical examples are demonstrated to illustrate the feasibility of virtual impedances. Emerging applications and future trends of virtual impedances in power electronic systems conclude this paper.

468 citations