Energies 2012, 5, 4008-4026; doi:10.3390/en5104008
energies
ISSN 1996-1073
www.mdpi.com/journal/energies
Article
Computation of Electromagnetic Torque in a Double Rotor
Switched Reluctance Motor Using Flux Tube Methods
Chockalingam Aravind Vaithilingam, Norhisam Misron *, Mohammad Reza Zare, Ishak Aris
and Mohammad Hamiruce Marhaban
Department of Electrical & Electronic Engineering, University Putra Malaysia, Serdang 43400 UPM,
Malaysia; E-Mails: aravindcv@ieee.org (C.A.V.); zareh81@gmail.com (M.R.Z.);
ishak@eng.upm.edu.my (I.A.); hamiruce@eng.upm.edu.my (M.H.M.)
* Author to whom correspondence should be addressed; E-Mail: norhisam@eng.upm.edu.my;
Tel.: +603-8946-6299; Fax: +603-8946-6327.
Received: 19 August 2012; in revised form: 22 September 2012 / Accepted: 4 October 2012 /
Published: 18 October 2012
Abstract: With their highly robust nature and simple design, switched reluctance machines
are finding their way into numerous modern day applications. However, they produce
oscillatory torque that generates torque ripple and mechanical vibrations. A double rotor
structure to maximize the flux linkage and thereby increase the torque generating capability
is proposed. As the machine operates close to saturation, the torque computation depends
heavily on the energy conversion as the rotor rolls over the stator for a fixed pole pitch.
The flux linkage characteristics are highly non-linear, hence estimation of the magnetic and
mechanical parameters is extremely cumbersome. Magnetic circuit analysis by interpretation
of the number of flux tubes using integration techniques at different positions of the
machine to develop the flux linkage characteristics of the double rotor structure is
presented. Computation of the inductances during the movement of rotor from unaligned to
aligned is crucial in determining the generated torque. Relevant equations of calculations
for inductance and flux linkages in the aligned, partially aligned and unaligned positions
are computed. The partially aligned computation is based on the average on two
intermediate positions, namely the 1/4th aligned and 3/4th aligned conditions. The static
torque characteristics based on the energy conversion principles are used to compute the
torque value. Results from simulation and experiments used for performance evaluation of
the proposed flux tube analysis for computation of the electro-magnetic torque
are presented.
OPEN ACCESS
