723 research outputs found
Tailoring optical fields emitted by nanometric sources
Here we study a simple way of controlling the emitted fields of
sub-wavelength nanometric sources. The system consists of arrays of
nanoparticles (NPs) embedded in optical active media. The key concept is the
careful tuning of NP's damping factors, which changes the eigenmode's decay
rates of the whole array. This, at long time, leads to a locking of relative
phases and frequencies of individual localized-surfaces-plasmons (LSPs) and,
thus, controlls the emitted field. The amplitude of the LSP's oscillations can
be kept constant by embedding the system in optical active media. In the case
of full loss compensation, this implies that, not only the relative phases, but
also the amplitudes of the LSPs remain fixed, leading us, additionally, to
interpret the process as a new example of synchronization. The proposed
approach can be used as a general way of controlling and designing the
electromagnetic fields emitted by nanometric sources, which can find
applications in optoelectronic, nanoscale lithography and probing microscopy
Torque Ripple Minimization in a Switched Reluctance Drive by Neuro-Fuzzy Compensation
Simple power electronic drive circuit and fault tolerance of converter are
specific advantages of SRM drives, but excessive torque ripple has limited its
use to special applications. It is well known that controlling the current
shape adequately can minimize the torque ripple. This paper presents a new
method for shaping the motor currents to minimize the torque ripple, using a
neuro-fuzzy compensator. In the proposed method, a compensating signal is added
to the output of a PI controller, in a current-regulated speed control loop.
Numerical results are presented in this paper, with an analysis of the effects
of changing the form of the membership function of the neuro-fuzzy compensator.Comment: To be published in IEEE Trans. on Magnetics, 200
- …