A hybrid method of analysis of low-speed linear induction motors

A current-excited low-speed solid-iron secondary single-sided linear induction motor (SLIM) with aluminum reaction rail is considered, A hybrid method of analysis consisting of field analysis in conjunction with the multilayer transfer-matrix concept with adjustment of secondary iron permeability to match the tangential magnetizing field in each layer is developed. It is shown that this method gives valuable information on permeability and flux penetration in secondary iron. Computed thrusts are in good agreement with test results.     

New solutions for a low-cost power electronic building block formatrix converters

This paper analyzes some aspects of integrating the matrix converter (MC) bidirectional switches into a power module. The analysis produces two optimal topologies for a power module: one for low-power and another for medium/high-power MCs. A new power module topology for a low-power three-phase-to-three- phase MC is proposed. By using bootstrap circuits to feed the gate-drivers, the proposed configuration requires only three insulated power supplies for a complete MC. This proposal constitutes a solution recommended in the low-power range, where low cost and low volume are the main objectives. Furthermore, a configuration of a power electronic building block for MCs is proposed. This includes the commutation control logic and the overcurrent protection, provides safe operation, and eliminates the specific problem of operating the bidirectional switches     

Complete Parameter Identification of Large Induction Machines From No-Load Acceleration–Deceleration Tests

This paper introduces an offline deterministic method for identification of inertia moment, mechanical losses, and electrical parameters for large induction machines, based on direct-on-line starting and natural slowdown tests, performed under no-load conditions. The static characteristic of absorbed power is used for the validation of results. Complete experimental results for a 6-kV four-pole 7500-kW machine are presented. The method brings significant cost savings for testing large induction machines.     

A comparison framework for breathing motion estimation methods from 4-D imaging

Motion estimation is an important issue in radiation therapy of moving organs. In particular, motion estimates from 4-D imaging can be used to compute the distribution of an absorbed dose during the therapeutic irradiation. We propose a strategy and criteria incorporating spatiotemporal information to evaluate the accuracy of model-based methods capturing breathing motion from 4-D CT images. This evaluation relies on the identification and tracking of landmarks on the 4-D CT images by medical experts. Three different experts selected more than 500 landmarks within 4-D CT images of lungs for three patients. Landmark tracking was performed at four instants of the expiration phase. Two metrics are proposed to evaluate the tracking performance of motion-estimation models. The first metric cumulates over the four instants the errors on landmark location. The second metric integrates the error over a time interval according to an a priori breathing model for the landmark spatiotemporal trajectory. This latter metric better takes into account the dynamics of the motion. A second aim of this paper is to estimate the impact of considering several phases of the respiratory cycle as compared to using only the extreme phases (end-inspiration and end-expiration). The accuracy of three motion estimation models (two image registration-based methods and a biomechanical method) is compared through the proposed metrics and statistical tools. This paper points out the interest of taking into account more frames for reliably tracking the respiratory motion.     

Design of a Three-Phase Flux Reversal Machine

A comprehensive design of a novel doubly-salient, stator-permanent magnet (PM) three-phase flux reversal machine (FRM) is presented in this paper. FRM has a robust and easy-to-build structure and is suitable for high-speed applications. Detailed design procedures and formulae are given. All of the dimensions of the FRM are derived. Basic parameters are calculated. The most important aspect of this design is to consider the wide operating speed range. The work presented may serve as a guideline for the general principle of design on three-phase FRM. Furthermore, the methodology and formulae introduced in this paper are also applicable to other types of PM and/or reluctance machine.     

The flux-reversal machine: a new brushless doubly-salientpermanent-magnet machine

A new brushless doubly-salient permanent-magnet machine called the flux-reversal machine is described. Design, analysis, construction, and experimental results for a prototype machine built as a single-phase, high-speed generator are presented. Qualitative comparisons are made with the other types of brushless machines in its class, using the flux-MMF diagram technique. An elementary CAD program developed for designing flux-reversal machines and the associated drive electronics is also described     

Wind turbine Generator modeling and Simulation where rotational speed is the controlled variable

To optimize the power produced in a wind turbine, the speed of the turbine should vary with the wind speed. A simple control method is proposed that will allow an induction machine to run a turbine at its maximum power coefficient. Various types of power control strategies have been suggested for application in variable speed wind turbines. The usual strategy is to control the power or the torque acting on the wind turbine shafts. This paper presents an alternative control strategy, where the rotational speed is the controlled variable. The paper describes a model, which is being developed to simulate the interaction between a wind turbine and the power system. The model is intended to simulate the behavior of the wind turbine using induction generators both during transient grid fault events and during normal operation. Sample simulation results for two induction generators (2/0.5 MW) validate the fundamental issues.     

BEGA-a biaxial excitation Generator for automobiles: comprehensive characterization and test results

This paper presents the design and test results for a biaxial excitation generator/motor for automobiles (BEGA), which has a three-phase stator and a salient-pole excited heteropolar rotor with multiple flux barriers filled with low-cost permanent magnets (PMs). For this new generator, the low-voltage regulation is obtained by the flux-barrier PM combination with field (excitation) low-power control and a full-power diode rectifier in the stator. Good power/volume and superior efficiency (up to 80%) are obtained at costs comparable to those of an existing Lundell generator. The generator configuration, principle, equations, finite-element field analysis, design optimization, performance characteristics, and test results, together with the generating system simulations, constitute the core of the paper.     

Combined Flux Observer With Signal Injection Enhancement for Wide Speed Range Sensorless Direct Torque Control of IPMSM Drives

This paper proposes a motion-sensorless control system using direct torque control with space vector modulation for interior permanent magnet synchronous motor (IPMSM) drives, for wide speed range operation, including standstill. A novel stator flux observer with variable structure uses a combined voltage-current model with PI compensator for low-speed operations. As speed increases, the observer switches gradually to a PI compensated closed-loop voltage model, which is solely used at high speeds. High-frequency rotating-voltage injection with a single D-module bandpass vector filter and a phase-locked loop state observer with a new synchronization procedure are used to estimate the rotor position, which is needed only by the current model in stator flux observer at low speeds. A new rotor speed estimator for the whole speed-loop range, based on the stator flux speed estimation with a new dynamic correction depending on estimated torque, is proposed and tested. Extensive simulation results and significant experimental results provided good performance for the proposed IPMSM sensorless system in more than 1:1000 speed range, under full-load operation, from very low speeds (1 r/min experimental) up to rated speed.