Search results for "square"

A novel implicit correlation for the operative temperature of a PV panel

2012

Abstract The operating temperature of a commercial PV panel strongly affects the electric power output of the devices. The prediction of the operating temperature therefore plays a central role in the economic and energy assessment of PV systems. The authors propose a new implicit correlation that takes into account the standard weather variables but also the regimen of PV panel in terms of the proximity to the maximum power points. Data coming from an experimental setup were processed by using the least squares technique. To validate the reliability of the correlation, a comparison between expected values and data from other common correlations were done. The results show that the regimen …

Least squares and genetic algorithms for parameter identification of induction motors

2001

Abstract This paper deals with off-line parameter identification of induction motors by means of least square (LS) techniques and genetic algorithms (GA), using stator voltages, stator currents and velocity as input–output data. For analytical identification by LS algorithms, filtering of experimental data is performed by means of anticausal filters. Two models useful for identification are derived in which the products of acceleration and rotor fluxes, usually neglected, are taken into account. The GA-based identification method consists of the determination of the best parameters which match input–output behaviour of the motor. Both methods are investigated and compared by means of experi…

Sensorless control of PMSM by a linear neural network: TLS EXIN neuron

2010

Sensorless vector control applied to the Permanent Magnet Synchronous Motors (PMSMs) is a very challenging subject. It permits obtaining high dinamical performance by exploiting increased reliability and also reduced cost. Among the different methodologies proposed in literature, a model based approach has been proposed here. In particular, the space vector equations of the PMSM have been re-elaborated to permit the use of a Least Squares technique. The problem has been then faced-up to with the so-called TLS EXIN neuron, which is a linear neural network able to solve the TLS problem on-line. Simulation tests have been done on both interior mounted and surface mounted machines.

Efficient FDTD analysis of discontinuities in a square coaxial waveguide

1996

Design of complex sheet metal forming processes: a new computer aided progressive approach

2010

The growing interest in sheet metal stamping processes, particularly in automotive industry, led to three main issues in this field: request of very complex shapes; growing interest in springback control; solution of multi-objective problems. This makes the design of the sheet metal stamping processes very difficult, since the number of both design variables and design objectives are progressively increased; therefore, proper design methodologies to reduce times and costs are highly required. In this paper, an innovative design approach able to manage and optimize complex stamping operations is proposed. In particular, a progressive design approach based on the integration between numerical…

U.I.R.D.A. – Unbuilt Italian Rationalism Digital Archive

2018

For twenty years, the architecture of Italian rationalism through the digital modelling has been investigated. Very often, the production of a model and the consequent representation of tridimensional views, in many case studies, as outcome of the research on architecture have been considered. Actually, the digital model, intended as a critical tool, has to be conceived as a ‘starting point' for graphic analysis of architecture and not as the outcome. Indeed, it is associated to other graphics, sometimes not ‘deducted' from the model, useful for the understanding/translation of architecture. The construction of the model is not the construction of a simple image, operation, which is often c…

Partial discharges on IGBT modules: Are sinusoidal waveforms sufficient to evaluate behavior?

2014

In recent years, the increasing use of AC-DC converters, especially in the field of renewable energy sources has led to the implementation of new modulation techniques, in particular the ones based on the pulse width modulation. The purpose of the present work is to verify the different behavior that is obtained when the components are subjected to the partial discharge test carried out with a sinusoidal waveform, and when they are subjected to PWM stress-type, similar to the actual signal generated by this type of electronic components. By considering equal rms value of the fundamental sine wave, the comparison has shown different partial discharges patterns.

Springback effect evaluation in three-dimensional stamping processes at the varying of blankholder force

2006

The quantitative evaluation of elastic springback in sheet metal stamping processes is still today a very interesting research topic, since this phenomenon causes a manufacturing shape defect. A measurement technique based on the shadow moiré method, already developed by the present authors, has been further upgraded and applied to evaluate the springback phenomenon in the deep drawing of square boxes, the basic three-dimensional stamping process. In particular this technique is able to determine the final lateral surface of the drawn parts, once extracted from the dies, and to compare such surface with the ideal one derived from the die's computer-aided design (CAD) geometry. Proper quant…

A Procedure for Selecting Representative Subsamples of a Population from a Simple Random Sample

2015

This paper proposes a procedure for selecting large subsamples drawn from a large simple random sample that are more representative of the population under study. By means of the so-called constant of proportionality, the procedure seeks to maximize the size of the subsample taken from a stratified random sample with proportional allocation, restricting it to a p-value high enough to achieve a good fit using Pearson’s chi-square goodness of fit test. The user has the freedom to choose between a larger subsample with poorer adjustment or a smaller subsample with a better fit. We use the Continuous Sample of Working Lives (CSWL), a set of micro data taken from Spanish Social Security records,…

Relationship between employee involvement and lean manufacturing and its effect on performance in a rigid continuous process industry

2015

Relationship between employee involvement and lean manufacturing and its effect on performance in a rigid continuous process industry DOI: 10.1080/00207543.2014.975852 Juan A. Marin-Garciaa* & Tomas Bonaviab Received: 1 Aug 2013 Accepted: 30 Sep 2014 Published online: 04 Nov 2014 This research aims to empirically test the effect of employee involvement on lean manufacturing (LM), and the effect of LM on production outcomes. Employee involvement is operationalised through four related variables: empowerment, training, contingent remuneration and communication. The effects are tested by recording management perceptions in a different industrial sector from those usually studied in previous re…