Showing 2 results for Mirsalim
A. Damaki Aliabad, M. Mirsalim, M. Fazli Aghdaei,
Volume 6, Issue 1 (March 2010)
Abstract
The air-gap of electrical machines may become non-uniform due to low accuracy of the manufacturing machinery, in assembling processes, or by aging. Detection and monitoring of this phenomenon is very important and of interest. There are several methods to model non-uniform air-gaps and to detect them by monitoring systems. One of the most widely used methods is by the analysis of the line currents. In this paper a new, simple and comprehensive method is presented to model and detect non-uniform air-gaps in synchronous generators with skewed rotors. The influence of non-uniform air-gaps on the harmonics of the induced voltage of the stator is investigated by the proposed method. Simulations are performed for three cases: uniform air-gap, static rotor eccentricity, and stator ovality in a two phase generator. The experimental results are also presented. The good correspondence between the simulation and the experimental results clearly validates the theoretical findings put forward in this paper.
M. M. Rezaei, M. Mirsalim,
Volume 6, Issue 2 (June 2010)
Abstract
Here, a new fuzzy direct torque control algorithm for induction motors is
proposed. As in the classical direct torque control, the inverter gate control signals directly
come from the optimum switching voltage vector look-up table, the best voltage space
vector selection is a key factor to obtain minimum torque and flux ripples. In the proposed
approach, the best voltage space vector is selected using a new fuzzy method. A simulation
model is built up and the torque and flux ripples of basic direct torque control and the
proposed method are compared. The simulation results show that the torque and flux
ripples are significantly decreased and in addition, the switching frequency can be fixed.
