Search results for " Tor"

High-Dose Torasemide is Equivalent to High-Dose Furosemide with Hypertonic Saline in the Treatment of Refractory Congestive Heart Failure.

2007

Objective: A randomised, double-blind study was performed to evaluate the effects of the combination of high-dose torasemide and hypertonic saline solution (HSS) infusion versus high-dose furosemide (frusemide) and HSS in the treatment of refractory New York Heart Association class IV congestive heart failure (CHF). Materials and methods: Eighty-four patients (55 males, 29 females) with refractory CHF, aged 55–84 years, with an ejection fraction <35%, serum creatinine <2 mg/dL, blood urea nitrogen ≤60 mg/dL, a reduced urinary volume and a low natriuresis, were randomised to two groups. Group 1 (27 males, 15 females) received an intravenous infusion of furosemide 500mg plus HSS (150mL of 1.4…

EKF-based estimation and control of electric drivetrain in offshore pipe racking machine

2016

A typical challenge for electric drivetrains is to reduce the number of sensors required for control action or system monitoring. This is particularly important for electric motors operating in offshore conditions, since they work in hostile environment which often damages data acquisition systems. Therefore, this paper deals with verification and validation of the extended Kalman filter (EKF) for sensorless indirect field-oriented control (IFOC) of an induction motor operating in offshore conditions. The EKF is employed to identify the speed of the induction motor based on the measured stator currents and voltages. The estimated speed is used in the motor speed control mode instead of a ph…

Performance Comparison of Electrical Motors equipped with slightly Asymmetrical Windings

2019

This paper presents a comparison between the performances of electrical machines equipped with slightly asymmetrical windings. More in detail, by modifying the stator geometry of an Interior Permanent Magnet Synchronous Machine equipped with a symmetrical winding configuration, other two slightly asymmetrical winding topologies are obtained. The three models are, then, analyzed by means of a finite element method (FEM) and the related results are compared in terms of cogging torque, static characteristics and leakage factor. The obtained results demonstrate that the adoption of slightly asymmetrical windings could be an interesting alternative solution during the design stage of electrical …

Torque peak reduction and overload monitoring of induction motors in offshore drilling operations

2015

Current drivetrain design procedures for electric actuation systems operating in offshore conditions typically consider two major requirements: to provide sufficient steady-state and maximum motor torques. As a result of this, no information regarding the transient state (e.g. during motor acceleration) is utilized when selecting drivetrain components. This leads to potentially dangerous situations when motors undergo saturation in these regions due to too high dynamic loads. A common reason for this (apart from lack of information about transient state when designing a drivetrain) is applying trapezoidal reference motion profiles that cause discontinuities in system acceleration and infini…

Dynamical Compensation of the Load Torque in a High-Performance Electrical Drive with an Induction Motor

2018

This paper describes a new method for dynamical estimation of load disturbance in induction motors by using Nonlinear Unknown Input Observers (NUIO). This estimation is then used to compensate dynamically the load torque in a Field Oriented Control (FOC) induction motor drive to increase its load-rejection capability. The method has been verified both in simulation and experimentally on a experimental rig.

The periods of the generalized Jacobian of a complex elliptic curve

2015

Abstract We show that the toroidal Lie group G = ℂ2/Λ, where Λ is the lattice generated by (1, 0), (0, 1) and (τ̂, τ͂), with τ̂ ∉ ℝ, is isomorphic to the generalized Jacobian JL of the complex elliptic curve C with modulus τ̂, defined by any divisor class L ≡ (M) + (N) of C fulfilling M − N = [℘ (τ͂) : ℘´(τ͂) : 1] ∈ C. This follows from an apparently new relation between the Weierstrass sigma and elliptic functions.

ARCINIEGA GARCÍA, Luis (coord.). Elías Tormo, apóstol de la historia del arte en España. Valencia: Institució Alfons el Magnánim. [Reseña]

2017

Angle Displacement Robust Controller for the Port Plate of the Hydraulic Transformer

2013

The hydraulic transformer is used in the hydraulic system to enhance the efficiency. However, how to control the angle displacement of the port plate is becoming a critical issue because of the new structure of the hydraulic transformer. This paper presents a new method for the angle displacement control system. Firstly, the basic principle of the system is presented. Then, the disturbance which is mainly the friction torque between the port plate and the cylinder block is calculated to estimate the range. Furthermore, the guaranteed cost control (GCC) is analyzed and combined with the disturbance and the characteristics of parameter uncertainties. Finally, the proposed control method is co…

A Method for Reduction of Cogging Torque in PM Machines Using Stepped Magnets

2006

The paper presents a general approach to minimization of the cogging torque in electrical machines using surface-mounted magnets with discrete skew angle. Two types of pole shapes, namely monotonic skewing as well as herringbone-shaped magnets are proposed for the purpose of reducing the cogging torque. The elaborated algorithm is validated against the 3D finite element model as well as experimental data obtained from physical model of the motor. The presented cost-effective method leads to a great reduction of cogging torque with only slight decrease of overall electromagnetic torque.

PVDF based vibration measurements and their correlation with torque estimation in a FOC induction motor drive

2008

This paper presents a study concerning the vibrations generated by an induction motor drive controlled by field oriented control algorithm (FOC). The aim of the study is to identify suitable measurement points and analysis techniques in order to achieve information about vibration generated by an electric drive. Vibrations take origin both by the torque generated by the motor and the motor supply through an inverter, then they are transmitted to neighbouring structures. Torque is estimated on the basis of the estimated flux linkage; vibrations have been both measured and analysed numerically by FEM at two points of the cradle. The numerical and experimental analysis have been carried out fo…