Showing 3 results for Commutation
A.vahedi, M.ramezani,
Volume 1, Issue 2 (4-2005)
Abstract
Dc excitation of the field winding in a synchronous machine can be provided by
permanent magnets. Permanent magnet synchronous machine (PMSM) can offer simpler
construction, lower weight and size for the same performance, with reduced losses and higher
efficiency. Thanks to the mentioned advantages these motors are widely used in different
application, therefore analysis and modeling of them, is very important. In this paper a new, fast
and simple method is presented to study performance of a PMSM connected to the converter.
For this purpose, average-value modeling and related analytical relations which leads to the
desired characteristics such as electromagnetic torque, dc current and dc voltage is presented
and applied to PMSM & converter system. The advantage of this model lie in reduction of
computation time compares to the other dynamic models while keeping accuracy quite
acceptable. This model is applicable for studying the steady-state performance of systems as
well as dynamic performance.
A. Halvaei-Niasar, A. Vahedi, H. Moghbelli,
Volume 3, Issue 3 (7-2007)
Abstract
This paper presents an original study on the generated torque ripples of phase
commutation in the Four-Switch, Three-Phase Inverter (FSTPI) Brushless DC (BLDC)
motor drive which is suitable for low cost applications. Analytic values of torque ripple and
commutation duration are obtained for different operation conditions. Moreover, limitation
on the speed range operation caused from splitting of the DC-link voltage is shown exactly.
Then a novel current control technique is developed to minimize the commutation torque
ripple for a wide speed range. The technique proposed here is based on a strategy that the
current slopes of the rising and the decaying phases during the commutation intervals can
be equalized by proper duty-ratios at commutations. Finally, the validity of the proposed
analysis and developed torque ripple reduction technique are verified via simulation.
M. Shahnazari, A. Vahedi,
Volume 5, Issue 4 (12-2009)
Abstract
An accurate average value model of synchronous machine-rectifier system considering the effect of stator resistance is derived in this paper. A proper voltage-behind-reactance synchronous machine model without any approximations is used for the generator that allows effective calculation of commutation displacement angle. All rectification modes of the rectifier are studied. A detailed switching model is implemented and validated against experimental measurements. The described average value model is evaluated through comparison of detailed simulation results and average model in time domain.
