Showing 3 results for H. Lesani
A. Fereidunian, H. Lesani, C. Lucas, M. Lehtonen, M. M. Nordman,
Volume 2, Issue 3 (October 2006)
Abstract
Almost all of electric utility companies are planning to improve their
management automation system, in order to meet the changing requirements of new
liberalized energy market and to benefit from the innovations in information and
communication technology (ICT or IT). Architectural design of the utility management
automation (UMA) systems for their IT-enabling requires proper selection of IT choices for
UMA system, which leads to multi-criteria decision-makings (MCDM). In response to this
need, this paper presents a model-based architectural design-decision methodology. The
system design problem is formulated first then, the proposed design method is introduced,
and implemented to one of the UMA functions–feeder reconfiguration function (FRF)– for
a test distribution system. The results of the implementation are depicted, and
comparatively discussed. The paper is concluded by going beyond the results and fair
generalization of the discussed results finally, the future under-study or under-review
works are declared.
Z. Nasiri-Gheidari, H. Lesani, F. Tootoonchian,
Volume 2, Issue 3 (October 2006)
Abstract
Hunting is a flutter associated with the synchronous speed that gives rise to the
gyro drifting errors and may cause objectionable time-displacement errors in video head
wheel drives and other precision scanning systems. In this paper, dynamic characteristics of
permanent Magnet hysteresis motors are presented and hunting is explained. New damping
techniques have been developed using optimized eigenvalues calculation. They are
calculated from LQR optimization method. In this damping method, a distinct reduction in
hunting has been archived. Furthermore field oriented control result of motor is presented
that have good effect on Hunting. Nearest agreement between simulated and measurement
results shows the accuracy of motor model. Comparison between this paper results and
other measured damping methods result are shown its success.
A. Darabi, T. Ghanbari, M. Rafiei, H. Lesani, M. Sanati-Moghadam,
Volume 4, Issue 4 (October 2008)
Abstract
Hysteresis motors are self starting brushless synchronous motors which are
being used widely due to their interesting features. Accurate modeling of the motors is
crucial to successful investigating the dynamic performance of them. The hysteresis loops
of the material used in the rotor and their influences on the parameters of the equivalent
circuit are necessary to be taken into consideration adequately. It is demonstrated that some
of the equivalent circuit parameters vary significantly with input voltage variation and other
operating conditions. In this paper, a comprehensive analysis of a hysteresis motor in the
start up and steady state regimes are carried out based on a developed d-q model of the
motor with time-varying parameters being updated during the simulation time. The
equivalent circuit of the motor is presented taking into account the major impact of the
input voltage. Simulation results performed in Matlab-Simulink environment prove that the
existing simple models with constant parameters can not predict the motor performance
accurately in particular for variable speed applications. Swings of torque, hunting
phenomenon, improvement of power factor by temporarily increasing the stator voltage and
start up behavior of the hysteresis machine are some important issues which can accurately
be analyzed by the proposed modeling approach.
