Performance optimization in switched reluctance motor drives

In this paper, switched reluctance motors (SRM) are proposed as an alternative for electric power assisted steering (EPAS) applications. A prototype machine has been developed as very attractive design for a steering electric motor, both from a cost and size perspective. A fourphase 8/6 SRM drive is designed for a rack type EPAS which should provide a maximum force of 10 kN. Two-dimension finite element analysis is used to validate the design

PWM Control of a Buck Converter with an Amorphous Core Coil

Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

Development of an electrochemical maltose biosensor

In this work, electrochemical maltose biosensors based on mutants of the maltose binding protein (MBP) are developed. A ruthenium II complex (Ru II ), which is covalently attached to MBP, serves as an electrochemical reporter of MBP conformational changes. Biosensors were made through direct attachment of Ru II complex modified MBP to gold electrode surfaces. The responses of some individual mutants were evaluated using square wave voltammetry. A maltose-dependent change in Faradic current and capacitance was observed. It is therefore demonstrated that biosensors using generically this family of bacterial periplasmic binding proteins (bPBP) can be made lending themselves to facile biorecognition element preparation and low cost electrochemical transduction

Using the Own Flexibility of a Climbing Robot as a Double Force Sensor

Force sensors are used when interaction tasks are carried out by robots in general, and by climbing robots in particular. If the mechanics and electronics systems are contained inside the own robot, the robot becomes portable without external control. Commercial force sensors cannot be used due to limited space and weight. By selecting the links material with appropriate stiffness and placing strain gauges on the structure, the own robot flexibility can be used such as force sensor. Thus, forces applied on the robot tip can be measured without additional external devices. Only gauges and small internal electronic converters are necessary. This paper illustrates the proposed algorithm to achieve these measurements. Additionally, experimental results are presented

Torque control of switched reluctance motors

This paper presents the performance of an instantaneous torque control method. The simulation and experimental results illustrate the capability of Switched Reluctance Motors (SRM) being used in the motor drive industry. Based on experimental data, the advantages of this control method and its disadvantages in practical implementation were studied. The model used in the simulation is the linear magnetic model which has the 12/8 structure, the same structure as the experimental switched reluctance motor

‘Framing’ and Arab World: the Spanish Press Coverage in the Tunisian Revolution

El presente trabajo analiza la cobertura periodística de la revolución tunecina (diciembre de 2010 – enero de 2011) a través de un análisis de contenido cuantitativo. Para lograrlo se han estudiado cuatro rotativos –ABC, El Mundo, El País y La Vanguardia–, profundizando en aspectos teóricos relativos al binomio framing-mundo araboislámico. Se ha comprobado que la experiencia democrática tunecina ha sido narrada desde la responsabilidad de sus actores (gobierno, ejército, manifestantes, etc.), el conflicto y el interés humano. Además, este acontecimiento supone un punto de inflexión que cierra el periodo previo marcado por el escaso interés informativo y tratamiento superficial.This work analyses the press coverage of the Tunisian revolution (December 2010 – January 2011) by means of a quantitative content analysis. In order to do so, four newspapers have been scrutinized – ABC, El Mundo, El País and La Vanguardia – focusing on theoretical aspects related to the framing-arabislamic world pairing. The research carried out confirms that Tunisian democratic experience has been related form the point of view of its actors’ responsibility (government, army, demonstrators, etc.), conflict and human interest. Moreover, this event stands as a turning point and puts an end to a previous period of little informative interest and superficial treatment

New system for measuring impact vibration on floor decking sheets

The present paper exposes an alternative system more simple and economic, consisting of a predefined beating device and a sensor able to determine, once produced the hit, the energy absorbed by the plate. After the impact being produced, the plate undergoes a deformation which absorbs part of the energy, being the reminding one transmitted to the slab and, at the same time, causing induced airborne noise in the adjoining room

Effective Power Signal Filtering using LC Filters with Air Core Coils

Computer controlled power supplies are usually expensive when high performance (power, wide voltage range, low ripple factor and low response time) are required. This paper presents a simple and effective computer controlled DC system based on a commercial V/f inverter combined with a three-phase bridge rectifier and a LC power filter. Because of the widely variable frequency range of the V/f inverter when a wide range of voltage is required, amorphous or ferromagnetic core coils are avoided, and air core coils become an excellent solution to implement the filter and increase the efficiency of the power system. The proposed method for designing the LC filter is based on the full dynamic model of the filter-load set and the selection of the desired poles of the system according to the load to be coupled. The proposed topology lets obtain good time responses (setting time less than 100 ms) and good ripple factor (less than 1%) without any overshooting, even when low voltage output is required

Eficacia luminosa en superficies horizontales en la estación de Radiación Solar e Iluminación de alta calidad del IDMP en Madrid

En la estación de radiación solar e iluminación de alta calidad del International Daylight Measurement Program (IDMP) en Madrid, ubicada en la Escuela Técnica Superior de Arquitectura de la Universidad Politécnica de Madrid (40º 25’ N, 3º 41’ W) se ha realizado un estudio detallado sobre la e-cacia luminosa de la radiación global, difusa y directa en super¬cies horizontales para todo tipo de cielos (despejados, cubiertos y parcialmente cubiertos). La parte experimental ha consistido en tomar medidas durante 5 segundos cada 15 minutos, diariamente, de iluminancias e irradiancias globales y difusas durante 15 meses, a partir de las cuales se han deducido modelos para determinar iluminancias, irradiancias y e¬cacias luminosas de la radiación solar para todo tipo de cielos en función de la altitud solar, considerando pequeños intervalos de 2,5º. El principal resultado obtenido es constatar que es posible deducir un modelo de e¬cacia luminosa a partir de modelos de iluminancia e irradiancia obtenidos previamente, muy útiles para estimar los niveles de iluminación en la edi¬cació

Multiprocessing for the particle tracking model MODPATH

Particle tracking has several important applications for solute transport studies in aquifer systems. Travel time distribution at observation points, particle coordinates in time and streamlines are some practical results providing information of expected transport patterns and interaction with boundary conditions. However, flow model complexity and simultaneous displacement of multiple particle groups leads to rapid increase of computational requirements. MODPATH is a particle tracking engine for MODFLOW models and source code displays potential for parallel processing of particles. This article addresses the implementation of this feature with the OpenMP library. Two synthetic aquifer applications are employed for performance tests on a desktop computer with increasing number of particles. Speed up analysis shows that dynamic thread scheduling is preferable for highly heterogeneous flows, providing processing adaptivity to the presence of slow particles. In simulations writing particles position in time, thread exclusive output files lead to higher speed up factors. Results show that above a threshold number of particles, simulation runtimes become independent of flow model grid complexity and are controlled by the large number of particles, then parallel processing reduces simulation runtimes for the particle tracking model MODPATH.Peer ReviewedPostprint (published version