Abstract: The spoke type rotor can be used to obtain magnetic
flux concentration in permanent magnet machines. This allows the
air gap magnetic flux density to exceed the remanent flux density
of the permanent magnets but gives problems with leakage fluxes
in the magnetic circuit. The end leakage flux of one spoke type
permanent magnet rotor design is studied through measurements and
finite element simulations. The measurements are performed in the
end regions of a 12 kW prototype generator for a vertical axis
wind turbine. The simulations are made using three dimensional
finite elements to calculate the magnetic field distribution in the
end regions of the machine. Also two dimensional finite element
simulations are performed and the impact of the two dimensional
approximation is studied. It is found that the magnetic leakage flux
in the end regions of the machine is equal to about 20% of the flux
in the permanent magnets. The overestimation of the performance by
the two dimensional approximation is quantified and a curve-fitted
expression for its behavior is suggested.
Abstract: The influence of slot wedges permeability on the electromagnetic performance of three-phase permanent magnet synchronous machine is investigated in this paper. It is shown that the back-EMF waveform, electromagnetic torque and electromagnetic torque ripple are all significantly affected by slot wedges permeability. The paper presents an accurate analytical subdomain model and confirmed by finite-element analyses.
Abstract: This paper presents a microstrip meandered open
circuited stub with bandstop characteristic. The proposed structure is
designed on a high frequency laminate with dielectric constant of 4.0
and board thickness of 0.508 millimeters. The scattering parameters
and electromagnetic field distributions at various frequencies are
investigated by modeling the structure with three dimensional
electromagnetic simulation tool. In order to describe the resonant
and bandstop characteristic of the meandered open circuited stub, a
Smith chart as well as electric field at various frequencies and phases
is illustrated accordingly. The structure can be an alternative method
in suppressing the harmonic response of a bandpass filter.
Abstract: This paper proposes a set of quasi-static mathematical
model of magnetic fields caused by high voltage conductors of
distribution transformer by using a set of second-order partial
differential equation. The modification for complex magnetic field
analysis and time-harmonic simulation are also utilized. In this
research, transformers were study in both balanced and unbalanced
loading conditions. Computer-based simulation utilizing the threedimensional
finite element method (3-D FEM) is exploited as a tool
for visualizing magnetic fields distribution volume a distribution
transformer. Finite Element Method (FEM) is one among popular
numerical methods that is able to handle problem complexity in
various forms. At present, the FEM has been widely applied in most
engineering fields. Even for problems of magnetic field distribution,
the FEM is able to estimate solutions of Maxwell-s equations
governing the power transmission systems. The computer simulation
based on the use of the FEM has been developed in MATLAB
programming environment.