Showing 3 results for Gholamian
M. Jamali, M. Mirzaie, S. A. Gholamian,
Volume 7, Issue 3 (September 2011)
Abstract
The phenomenon of magnetizing inrush is a transient condition, which occurs primarily when a transformer is energized. The magnitude of inrush current may be as high as ten times or more times of transformer rated current that causes malfunction of protection system. So, for safe running of a transformer, it is necessary to distinguish inrush current from fault currents. In this paper, an equivalent instantaneous inductance (EII) technique is used to discriminate inrush current from fault currents. For this purpose, a three-phase power transformer has been simulated in Maxwell software that is based on finite elements. This three-phase power transformer has been used to simulate different conditions. Then, the results have been used as inputs in MATLAB program to implement the equivalent instantaneous inductance technique. The results show that in the case of inrush current, the equivalent instantaneous inductance has a drastic variation, while it is almost constant in the cases of fault conditions.
A. Ebadi, M. Mirzaie, S. A. Gholamian,
Volume 8, Issue 2 (June 2012)
Abstract
Induction motor is the most popular load in the industry, it is very important to
study about the effects of voltage quality on induction motor performance. One of the most
important voltage quality problems in power system is voltage unbalance. This paper
evaluates and compares two methods including finite element method (FEM) and
equivalent electrical circuit simulation for investigation of the effects of voltage unbalance
conditions on the performance of a three- phase induction motor. For this purpose, a threephase
squirrel cage induction motor is simulated using Finite Element Method and
equivalent electrical circuit parameters of the FEM model is estimated by genetic
algorithm. Then, some unbalanced voltages are applied on the FEM model of the Motor
and the resulted power and losses are compared with calculated values using equivalent
electrical circuit simulation in same voltage conditions.
M. E. Moazzen, S. A. Gholamian, M. Jafari-Nokandi,
Volume 13, Issue 2 (June 2017)
Abstract
Permanent magnet synchronous generators (PMSG) have a huge potential for direct-drive wind power applications. Therefore, optimal design of these generators is necessary to maximize their efficiency and to reduce their manufacturing cost and total volume. In this paper, an optimal design of a six-phase 3.5 KW direct-drive PMSG to generate electricity for domestic needs is performed. The aim of optimal design is to reduce the manufacturing cost, losses and total volume of PMSG. To find the best design, single/multi-objective design optimization is carried out. Cuckoo optimization algorithm (COA) is adopted to solve the optimization problem. Comparison between the results of the single-objective and multi-objective models shows that simultaneous optimization of manufacturing cost, losses and total volume leads to more suitable design for PMSG. Finally, finite-element method (FEM) is employed to validate the optimal design, which show a good agreement between the theoretical work and simulation results.
