Showing 3 results for Darabi
Lesani, Darabi, Nasiri Gheidari, Tootoonchian,
Volume 2, Issue 1 (January 2006)
Abstract
In this paper, a new field oriented control scheme with maximum torque for permanent magnet hysteresis synchronous (PMHS) motor has been presented. Vector control method provides significant improvement to the dynamic performance of ac motors but in this method d- axis current is controlled such as the ratio of motor torque to motor current is a maximum, then the dynamic performance will be very fast. Furthermore, d and q axis currents are limited such as stator winding currents remain in the allowed range. Feedback method is used for the decoupling the torque-current component from the fluxcurrent component so these two components can be independently controlled. Simulation results for the motor are given and test results validate the theoretical performances.
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.
A. Darabi, M. Yousefisefat, M. Nikkhoo,
Volume 10, Issue 1 (March 2014)
Abstract
Quadrature-axis reactance for various reasons comes into account as one of the most important parameters of salient pole synchronous machine. There are several common standard methods for measuring this parameter that also have been explained with some details in the standards, scientific papers and text books. One of these methods is the maximum lagging current test that is done simply at no-load, having a three phase voltage source and applying very low power even for a high power machine. How this experiment is done is described at some references such as the books related to electrical machinery. This paper presents a detail analysis and description of the test and some simulation results regarding the performance of the machine during pole-slipping. It is shown when the reversal field current is increased very slowly, the transient of the pole-slipping commences at load angle equal to 45 degrees or by a better language at 225 instead of zero which is the common opinion of almost all the previously published literatures. In this paper, a realistically developed analysis of the test is presented applying appropriate assumptions. The maximum lagging current test is then simulated applying a small salient pole machine with the rated 31.5 kVA using Matlab/Simulink. Some simulation results are illustrated that prove correctness and validity of the new analysis and the proof described by the present paper.
