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102 results on '"Amiri, Navid"'

3. Electrical Machines in Electromagnetic Transient Simulations: Focusing on efficient and accurate models

Author

Mostajeran, Erfan, Amiri, Navid, Ebrahimi, Seyyedmilad, and Jatskevich, Juri

Abstract

Electrical machines are extensively used in our everyday life. On the one hand, this can be seen in the rapid growth of generation from renewable energy sources such as wind, hydropower, tidal, etc. On the other hand, at the energy utilization and consumption end visible to most people, we are also witnessing revolutionary changes in many sectors, such as the electrification of all types of transportation, i.e., electric vehicles, industry-wide initiatives for more-electric aircraft and more-electric ships, military vehicles and defense systems, industrial automation, industrial and personal robots, medical devices and instruments, flying drones, electronic toys, and the multitude of household appliances and devices, all of which are designed and built with electric motors of various types and sizes.

Published
2023
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20. Efficient modelling of special purpose multi-phase electrical machines for transient simulation programs

Author

Amiri, Navid

Abstract

Design and analysis of power systems has always been reliant on mathematical models of power system components and their implementation in sophisticated electromagnetic transient (EMT) simulation programs. Electric machines are the dominantly used components in models of power grids, and in most simulation programs rotating machines are represented using lumped-parameter models based on magnetically-coupled phase windings. Advancements in semi-conductor devices have allowed conventional three-phase machines as well as multi-phase machines (with more than three electrical phases) to be used with power electronic interfaces in wide range of electromechanical energy conversion applications, including advanced motor drive systems as well as integration of renewable energy. The multi-phase machines, at the expense of their increased complexity, may also provide additional advantages over the conventional three-phase machines, e.g. reduced power per phase, reduced semi-conductor current/voltage rating per phase, increased reliability, fault tolerant operation, etc. However, such multi-phase machines have unique electromagnetic characteristics and complex mathematical models which also become additional challenge in terms of both implementation and numerical performance in simulation programs. The main goal of this dissertation is to propose accurate and numerically efficient models of multi-phase machines which also consider key characteristics such as magnetic saturation and flux harmonics. In this dissertation, the voltage-behind-reactance (VBR) methodology has been used to derive new models for wound-rotor six-phase synchronous machines (including leakage flux cross-coupling and magnetic saturation), five-phase machines (including flux harmonics and inter-harmonic couplings) and also three-phase saturable induction machines considering flux harmonic distortions. The new models possess the advantage of constant-parameter interfacing circuits when implemented in state-variable-based (SVB) simulation programs, which has not been possible prior to this work. Numerous case studies demonstrate the advantageous numerical accuracy and efficiency of the proposed models, and their beneficial impact on simulation performance compared to the alternative existing state-of-the-art machine models of the same class. It is envisioned that due to their numerous advantages the new models will become included in many commonly-used commercial EMT programs, and will benefit thousands of researchers and engineers worldwide.

Published
2019
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37. Average-Value Modeling of Diode Rectifier Systems Under Asymmetrical Operation and Internal Faults.

Author

Ebrahimi, Seyyedmilad, Amiri, Navid, Huang, Yingwei, Wang, Liwei, and Jatskevich, Juri

Subjects
*ELECTRIC current rectifiers, *ELECTRIC power system faults, *ELECTRIC machines
Abstract

Line-commutated rectifiers (LCRs) are extensively utilized in exciters of large electrical machines, ac–dc power systems of ships, vehicles, aircraft, and many other industrial applications. Efficient and accurate computer simulations are necessary to analyze various aspects of such systems under both normal and unbalanced/faulty operating conditions. The so-called parametric average-value modeling (PAVM) technique has been recently developed and shown to provide accurate and computationally efficient models of power-electronic converters for system-level simulations. In this paper, the PAVM methodology is extended to LCRs with internal faults. The new formulation considers the asymmetrical operation of rectifiers by including the ac-side characteristic (i.e., 5th, 7th, etc.) and non-characteristic (i.e., 2nd, 3rd, 4th, etc.) harmonics in both positive and negative sequences as well as dc components that may be present on ac variables. The proposed PAVM is verified by experimental measurements and detailed model and is demonstrated to have excellent accuracy under various operating modes and fault configurations. [ABSTRACT FROM AUTHOR]

Published
2018
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