Hossein Nejadi Koti, Ph.D.
Adjunct Assistant Professor
- Milwaukee WI UNITED STATES
Dr. Koti's expertise includes electric motors and generators, electromagnetic systems, and fault diagnoses in magnet motors and generators.
Education, Licensure and Certification
Ph.D.
Electrical Engineering
Marquette Univeristy
2023
M.S.
Electrical Engineering
University of Tehran
2016
B.S.
Electrical Engineering
Shahid Chamran University of Ahwaz
2012
Biography
Areas of Expertise
Social
Selected Publications
Fast steady-state analysis in time-stepping finite-element simulation of induction motors based on virtual blocked rotor techniques
IEEE Transactions on Industry ApplicationsHao Chen, Hossein Nejadi Koti, Nabeel AO Demerdash, Khwaja M Rahman, Yue Sun
2020
Induction motor time-stepping finite-element analysis requires a lengthy transient response time to build up the complete steady-state magnetic field distribution in both stator and rotor. Various methods to speed up the convergence of the time-stepping finite-element (TS-FE modeling are investigated in this article. A so-called “virtual blocked rotor” technique is developed by using an eddy-current solver in the frequency domain to approximate the initial conditions, including the frozen permeabilities, potentials/energies, the stator winding and rotor bar currents, etc. Then, these well-prepared initial conditions are imported into the transient TS-FE time-domain solver (model). Significant reduction of the length of the transient response to reach convergence is accomplished.
Eccentricity fault diagnosis indices for permanent magnet machines–state of the art
IET Electric Power ApplicationsJawad Faiz, Hossein Nejadi Koti
2019
Eccentricity fault with 10% severity is probably the only existing fault in a brand new healthy electrical machine that is acceptable as a manufacturing tolerance. This fault can be developed due to a continuous pull between stator and rotor, even in a de-energized machine. So, it must be diagnosed,and its severity monitored. The authors introduced and criticized various indices for eccentricity fault diagnosis. Advantages, drawbacks, and ambiguous points of each index and potential ground for improvement of these techniques are addressed. Moreover, different eccentric PM machine modelling techniques are reviewed and environmental factors affecting the eccentricity fault detection process are discussed. This survey covers all direct current and alternating current PM machines.
Inductance-based inter-turn fault detection in permanent magnet synchronous machine using magnetic equivalent circuit model
Electric Power Components and SystemsJawad Faiz, Hossein Nejadi-Koti, Amir Hossein Exiri
2017
This paper presents an inductance-based method for detection of inter-turn fault in permanent magnet synchronous machines (PMSM). The reason for using inductance for fault detection and its severity estimation is the obvious impact of the fault on the inductances. This fault reduces the effective number of turns and therefore inductances. The PMSM is modeled using magnetic equivalent circuit (MEC). This method takes into account the impacts of stator teeth, rotor yoke, and stator winding distribution precisely. So, it is shown that the MEC method is superior to other analytical methods such as winding function. The governing equations in different parts of the machine are proposed, and the MEC equations of the PMSM are developed. First, healthy and faulty PMSM is simulated using MEC for different severities of the fault.
