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This paper analyzes the incline unbalanced magnetic pull (IUMP) generated in the permanent magnetic synchronous motor (PMSM) with the rotor misalignment. The motor magnetic field in such a motor is asymmetric, and both the magnitude and the action point of UMP vary in motor operation. This paper presents an analytical model for analyzing the 3-D effects of the UMP induced by the misalignment rotor. The numerical simulation results prove the effectiveness of the proposed analytic model. [ABSTRACT FROM PUBLISHER]

This paper describes analytical prediction and measurements for the inductance profile of a linear switched reluctance motor (LSRM). First, analytical solutions for flux density due to mover winding currents are derived, for the case when the mover is located at aligned and unaligned positions. Then, using the inductance at aligned and unaligned positions obtained from two-dimensional (2-D) analytical solutions and Fourier series expansion proposed in this paper, we predict the inductance profile of the LSRM analytically. Finally, inductance measurements are given to confirm the analysis. [ABSTRACT FROM AUTHOR]

Direct simulation of the starting process of an electric machine using a 3-D transient finite-element analysis (FEA) is very time consuming. To overcome this difficulty, an interpolative finite-element modeling of a large solid pole synchronous motor (SPSM) is presented and its starting process is simulated in this paper. In order to take into account the effects of cooling ducts and end turns, three different simplified 3-D finite-element models (FEMs) are proposed to reduce the computing time and save memory storage. With the proposed algorithm, an appropriate postprocess is exploited to deduce an effective core length and an end-turn leakage inductance. Then, a 2-D transient FEM with the modified parameters from 3-D FEA is used to simulate the starting process. The proposed method is validated by the test results of a 15000-hp, 13.2-ky, 4-pole SPSM. [ABSTRACT FROM AUTHOR]

In this paper, we report a method for nonuniform data-dependent noise prediction (DDNP), in which the noise predictive filters do not have an identical order (number of taps). To accommodate this new architecture, we implemented a partial decision feedback strategy for branch metric computations of the higher order predictive filters. Theoretical analysis and computer simulations show that our proposed DDNP can achieve a better tradeoff between detection performance and computational complexity compared with the previously reported DDNP. [ABSTRACT FROM AUTHOR]

We consider in this paper the possibility of using a low-density parity-check (LDPC) code as the complete error control system in a magnetic recording channel. We compare the performance of selected LDPC codes with two Reed-Solomon (RS) code schemes on an extended partial-response class 4 (EPR4) channel, with particular emphasis on their performance in noise bursts (induced by media defects or thermal asperities). We quantify the performance of LDPC codes in noise bursts via a maximum-burst-length parameter, and we present a simple algorithm for computing this parameter. We find some very promising initial results: the LDPC codes are very robust against large noise bursts (128 bits long or more), and are superior to the RS schemes examined in the measurable error rate region. The extent to which they are superior depends on the particular LDPC scheme involved, and the results provide motivation for further investigation in this area. [ABSTRACT FROM AUTHOR]

This paper proposes and implements a new three-phase 12/8-pole brushless doubly fed doubly salient machine (BDFDS) for wind power generation. The key is to design and control the proposed BDFDS machine in such a way that the system can offer constant output voltage and efficiency optimization over a wide range of wind speeds. First, the machine output power equation is derived to initialize the machine dimensions. Second, finite-element analysis is performed to finalize the machine dimensions as well as to determine the machine parameters and characteristics. Third, the system model is formulated and applied for computer simulation. Finally, the whole system is prototyped for verification, with emphasis on the constant voltage regulation and efficiency optimization. [ABSTRACT FROM AUTHOR]

This paper investigates the iron losses that occur in a brushless doubly-fed reluctance machine. This is a novel machine that is still being researched. It is found that the iron losses are quite high when using an axially-laminated rotor (as often used in a synchronous reluctance machine) in this application. Simulations are carried out using finite element analysis and the level of rotor eddy-current loss verified with experimental tests. [ABSTRACT FROM AUTHOR]

This paper studies the calculation of torque in a permanent magnet motor finite element simulation using an energy difference method. It is found that this is a simple yet powerful method of torque calculation and allows both pulsating and average torque to be calculated. The method is compared to other techniques. [ABSTRACT FROM AUTHOR]

In this paper, a design optimization method for a consequent-pole bearingless motor is presented. This produces stable magnetic suspension under motor torque generation. The suspension force reduction and direction error, which can be caused by torque generation, are limited in the proposed designs. In the optimization routine, the number of suspension and torque winding turns and air-gap length are carefully assessed. Three stators are constructed for experimental verification. The amplitude and direction errors for the suspension force are found to be within acceptable ranges and the operation of the magnetic suspension is acceptable. [ABSTRACT FROM AUTHOR]

This paper presents a numerical method for accurate predictions of magnetic fields in permanent magnet brushless dc motors with slotted stator core. The method allows both the radial and tangential component of the air gap field to be computed accurately in an analytical form. It is shown that a significant improvement in the accuracy of magnetic force predictions is achieved when compared to the existing analytical solutions. The method is validated using finite element simulations and experimental results. [ABSTRACT FROM AUTHOR]

This paper analyzes the effect of permanent magnets (PMs) on the formation of chaos in doubly salient PM (DSPM) machines. Based on the newly derived nonlinear system dynamical equation, the corresponding Poincaré map and bifurcation diagram show that the sizing of PMs significantly affects the stability of DSPM machines. Chaos may be resulted if the PMs are not properly designed. Both computer simulations and experimental results are provided, to support the theoretical derivation. [ABSTRACT FROM AUTHOR]

In this paper, we present a general approach for constructing high-rate cycle codes having girth 12 which achieve the lower bound on the block length. An efficient encoding algorithm is also proposed for this class of codes. We estimate the word error rate of the cycle codes for additive white Gaussian noise (AWGN) channels under maximum likelihood decoding, using the minimum distance and its multiplicity. These estimates are compared to simulation results with iterative soft decoding. The performance of these codes for partial response channels is studied under iterative soft decoding using computer simulations. [ABSTRACT FROM AUTHOR]

Bit patterned media are being studied as a promising approach for achieving storage densities beyond 1 Tb/in2 in magnetic recording disk drives. In this investigation we study the flying characteristics of a so-called "spherical pad slider" where a spherical pad is implemented on the top of the trailing pad of a traditional slider. We numerically simulate the flying characteristics and slider attitude of the spherical pad slider and compare this design with a traditional slider flying over the same bit patterned media. The effect of the design parameters of the bit pattern and the spherical pad on the flying characteristics is investigated. [ABSTRACT FROM AUTHOR]

Presents the parametric analyses of a sliding electrical contact problem by using a finite-element (FE) software Electromechanical Analysis Program in Three Dimensions (EMAP3D) and a Beowulf cluster. Components of an FE analyses in electromagnetic launch; Steps of the FE solution; Reasons for using the iterative solution algorithms.

Flux-switching permanent magnet motors are a form of brushless dc motor, with a simple salient-pole rotor, similar to that of a switched reluctance motor, and the excitation coils and permanent magnets on the stator. The influence of the rotor pole-arc and asymmetry on the torque-rotor position characteristic of a single-phase flux-switching permanent magnet motor is investigated by finite-element analysis, and validated experimentally, with particular reference on starting capability. [ABSTRACT FROM AUTHOR]

In flux-switching permanent magnet machines, a significant leakage flux exists at the outer surface of the stator core. Since the leakage flux varies as the rotor rotates, a significant eddy current loss may be induced in the nonmagnetic frame. The leakage flux and the associated eddy current loss in a representative flux-switching machine are investigated by finite element analysis, on both open-circuit and at rated load, predicted results being validated experimentally. In addition, the effectiveness of introducing slots in the frame to reduce the eddy current loss is investigated. [ABSTRACT FROM AUTHOR]

Dynamic load process was studied systematically with a novel three dimensional (3-D) flying height-attitude testing system and also by simulation. Flying height and pitch/roll angle histories in a load process observed with the 3-D system were compared with simulations. It is observed with the 3-D system that the slider shows strong fluctuations at high vertical load velocities and different disk rpms. With the help of simulation results, we can have a better understanding of the phenomena observed with the 3-D system and the observed load process plays an important role to evaluate and improve simulation code. [ABSTRACT FROM AUTHOR]

Describes the parallelization of the Electromechanical Analysis Program in Three Dimensions based on the Jacobi preconditioned conjugate gradient. Analysis of the performance of the parallel algorithm; Details of the Jacobi preconditioning matrix; Application of the algorithm on a railgun with block armature.