Abstract: This paper presents an optimal design of linear phase
digital high pass finite impulse response (FIR) filter using Improved
Particle Swarm Optimization (IPSO). In the design process, the filter
length, pass band and stop band frequencies, feasible pass band and
stop band ripple sizes are specified. FIR filter design is a multi-modal
optimization problem. An iterative method is introduced to find the
optimal solution of FIR filter design problem. Evolutionary
algorithms like real code genetic algorithm (RGA), particle swarm
optimization (PSO), improved particle swarm optimization (IPSO)
have been used in this work for the design of linear phase high pass
FIR filter. IPSO is an improved PSO that proposes a new definition
for the velocity vector and swarm updating and hence the solution
quality is improved. A comparison of simulation results reveals the
optimization efficacy of the algorithm over the prevailing
optimization techniques for the solution of the multimodal, nondifferentiable,
highly non-linear, and constrained FIR filter design
problems.
Abstract: The fine structure of supercavitation in the wake of a
symmetrical cylinder is studied with high-speed video cameras. The
flow is observed in a cavitation tunnel at the speed of 8m/sec when the
sidewall and the wake are partially filled with the massive cavitation
bubbles. The present experiment observed that a two-dimensional
ripple wave with a wave length of 0.3mm is propagated in a
downstream direction, and then abruptly increases to a thicker
three-dimensional layer. IR-photography recorded that the wakes
originated from the horseshoe vortexes alongside the cylinder. The
wake was developed to inside the dead water zone, which absorbed the
bubbly wake propelled from the separated vortices at the center of the
cylinder. A remote sensing classification technique (maximum most
likelihood) determined that the surface porosity was 0.2, and the mean
speed in the mixed wake was 7m/sec. To confirm the existence of
two-dimensional wave motions in the interface, the experiments were
conducted at a very low frequency, and showed similar gravity waves
in both the upper and lower interfaces.
Abstract: According to the density of the chips, designers are
trying to put so any facilities of computational and storage on single
chips. Along with the complexity of computational and storage
circuits, the designing, testing and debugging become more and more
complex and expensive. So, hardware design will be built by using
very high speed hardware description language, which is more
efficient and cost effective. This paper will focus on the
implementation of 32-bit ALU design based on Verilog hardware
description language. Adder and subtracter operate correctly on both
unsigned and positive numbers. In ALU, addition takes most of the
time if it uses the ripple-carry adder. The general strategy for
designing fast adders is to reduce the time required to form carry
signals. Adders that use this principle are called carry look- ahead
adder. The carry look-ahead adder is to be designed with combination
of 4-bit adders. The syntax of Verilog HDL is similar to the C
programming language. This paper proposes a unified approach to
ALU design in which both simulation and formal verification can
co-exist.
Abstract: This paper presents the optimum design for a double
stator, cup rotor machine; a novel type of BLDC PM Machine. The optimization approach is divided into two stages: the first stage is
calculating the machine configuration using Matlab, and the second stage is the optimization of the machine using Finite Element
Modeling (FEM). Under the design specifications, the machine
model will be selected from three pole numbers, namely, 8, 10 and 12 with an appropriate slot number. A double stator brushless DC
permanent magnet machine is designed to achieve low cogging torque; high electromagnetic torque and low ripple torque.
Abstract: The paper presents a detailed calculation of characteristic of five different topology permanent magnet machines for high performance traction including hybrid -electric vehicles using finite element analysis (FEA) method. These machines include V-shape single layer interior PM, W-shape single-layer interior PM, Segment interior PM and surface PM on the rotor and with distributed winding on the stator. The performance characteristics which include the back-emf voltage and its harmonic, magnet mass, iron loss and ripple torque are compared and analyzed. One of a 7.5kW IPM prototype was tested and verified finite-element analysis results. The aim of the paper is given some guidance and reference for machine designer which are interested in IPM machine selection for high performance traction application.
Abstract: The proper selection of the AC-side passive filter
interconnecting the voltage source converter to the power supply is
essential to obtain satisfactory performances of an active power filter
system. The use of the LCL-type filter has the advantage of
eliminating the high frequency switching harmonics in the current
injected into the power supply. This paper is mainly focused on
analyzing the influence of the interface filter parameters on the active
filtering performances. Some design aspects are pointed out. Thus,
the design of the AC interface filter starts from transfer functions by
imposing the filter performance which refers to the significant current
attenuation of the switching harmonics without affecting the
harmonics to be compensated. A Matlab/Simulink model of the entire
active filtering system including a concrete nonlinear load has been
developed to examine the system performances. It is shown that a
gamma LC filter could accomplish the attenuation requirement of the
current provided by converter. Moreover, the existence of an optimal
value of the grid-side inductance which minimizes the total harmonic
distortion factor of the power supply current is pointed out.
Nevertheless, a small converter-side inductance and a damping
resistance in series with the filter capacitance are absolutely needed
in order to keep the ripple and oscillations of the current at the
converter side within acceptable limits. The effect of change in the
LCL-filter parameters is evaluated. It is concluded that good active
filtering performances can be achieved with small values of the
capacitance and converter-side inductance.
Abstract: This paper demonstrates the application of craziness based particle swarm optimization (CRPSO) technique for designing the 8th order low pass Infinite Impulse Response (IIR) filter. CRPSO, the much improved version of PSO, is a population based global heuristic search algorithm which finds near optimal solution in terms of a set of filter coefficients. Effectiveness of this algorithm is justified with a comparative study of some well established algorithms, namely, real coded genetic algorithm (RGA) and particle swarm optimization (PSO). Simulation results affirm that the proposed algorithm CRPSO, outperforms over its counterparts not only in terms of quality output i.e. sharpness at cut-off, pass band ripple, stop band ripple, and stop band attenuation but also in convergence speed with assured stability.