Search results for "Synchro"
showing 10 items of 886 documents
On the impact of within-die process variation in GALS-Based NoC Performance
2012
[EN] Current integration scales allow designing chip multiprocessors (CMP), where cores are interconnected by means of a network-on-chip (NoC). Unfortunately, the small feature size of current integration scales causes some unpredictability in manufactured devices because of process variation. In NoCs, variability may affect links and routers causing them not to match the parameters established at design time. In this paper, we first analyze the way that manufacturing deviations affect the components of a NoC by applying a new comprehensive and detailed within-die variability model to 200 instances of an 8¿8 mesh NoC synthesized using 45 nm technology. Later, we show that GALS-based NoCs pr…
Sensorless Control of PMSM Fractional Horsepower Drives by Signal Injection and Neural Adaptive-Band Filtering
2012
This paper presents a sensorless technique for permanent-magnet synchronous motors (PMSMs) based on high-frequency pulsating voltage injection. Starting from a speed estimation scheme well known in the literature, this paper proposes the adoption of a neural network (NN) based adaptive variable-band filter instead of a fixed-bandwidth filter, needed for catching the speed information from the sidebands of the stator current. The proposed NN filter is based on a linear NN adaptive linear neuron (ADALINE), trained with a classic least mean squares (LMS) algorithm, and is twice adaptive. From one side, it is adaptive in the sense that its weights are adapted online recursively. From another si…
Development of the control card for the digitizers of the second generation electronics of AGATA
2012
In this work, the features and development process of the novel control card for the digitizers of AGATA are presented. The board is part of the new hardware proposed for the electronic system of the experiment. In particular, the control card provides the sampling clock for the digitizers, contributes to the synchronization of the digital data and performs the slow control of its associated digitizer cards.
Considering Learners’ Perceptions in Designing Effective 21st Century Learning Environments for Basic Education in Finland
2014
Focusing on so called Key Competences or 21st Century Skills urges educational organizations to redesign their psychosocial and physical learning environments. Inspired by studies indicating that considering learners’ perceptions of learning environments can have a positive impact on learning and wellbeing, our study aims at developing design principles for involving learners in the learning environment design. This pilot case study analyzed 7- to 14-years old Finns’ (n = 80) perceptions by using web questionnaires and design workshops. The results are in line with research indicating that Finnish learners value aspects such as safety and peacefulness, the possibilities for rest and physica…
A study on the influence of permanent magnet dimensions and stator core structures on the torque of the disc-type brushless DC motor
2000
This paper presents a three-dimensional analysis of the magnetic field distribution for a disc-type, double-sided, permanent magnet, brushless dc motor with a toroidal stator core. Calculations are carried out using the OPERA (3D) package with the TOSCA module. The electromagnetic torque is determined from the Maxwell stress tensor. For comparison, various permanent magnet dimensions and slotless vs. quasi-slotted stator cores are analysed, with an iron powder-resin composite effectively used to imitate the slotted core. The torque ripple is shown to be effectively reduced by appropriate permanent magnet dimensions. The simulation results are in good agreement with experimental data obtaine…
Overcoming synchronization issues in wireless technology Partial Discharge measurement
2016
In this paper, several aspects of the fundamentals of wireless Partial Discharge (PD) measurements are first discussed. Then, the relevance of the problem of voltage synchronization in PD wireless diagnosis is outlined. When portable instruments are used for PD detection, the main issue is the voltage measurement at the site where the PD detection is carried out. When such analysis is carried out over shielded cables, the AC (50/60 Hz) voltage reference signal is not easily detectable, while one of the basic parameters for PD diagnosis, the displacement of the inception voltage of the PD as compared to the reference voltage, is not available. Even if highperformance sensors are readily avai…
Lighting in educational environments: An example of a complete analysis of the effects of daylight and electric light on occupants
2013
Abstract Light induces not only visual responses but also non-visual effects, indeed it affects performance, mood, attention and influences the synchronization of the biological clock. Duration, timing, intensity and the spectral power distribution of the light that reaches the eyes can have influence on human circadian rhythm and consequently on health. Given the important impact of the non-visual responses on people wellbeing, developing a model that allows lighting designers to predict them is a fundamental goal. In this paper a case study is reported: a series of measurements were carried out in a University classroom in order to study daylight and electric light characteristics and als…
Synchronization techniques for power quality instruments
2004
The measurement of voltage characteristics in power systems requires the accurate estimation of the power supply frequency and signal synchronization, even in the presence of disturbances. The authors developed and tested two innovative techniques for instrument synchronization. The first is based on signal spectral analysis techniques performed by means of the Chirp-Z transform analysis. The second is a phase-locked loop (PLL) software based on a time-domain coordinate transformation and an innovative phase-detection technique. To evaluate how synchronization techniques are adversely affected by the application of a disturbing influence, experimental tests were carried out, taking into acc…
Electrostatic synchronous generator model of an Inverter-Based Distributed Generators
2015
In this paper, the idea of modelling the Inverter-Based Distributed Generators by using the concept of Electrostatic synchronous machines is discussed. A mathematical model of the inverter has been established which depends on the dc bus voltage, modulation index and frequency of the system. Two mathematical models have been developed: a small signal model and a steady-state model. These mathematical models will be helpful in studying the stability of a microgrid; especially when studying the transient stability performance of on-grid operation of converter-based distributed generator with multi-machine microgrid. Simulation results using Matlab/Simulink are carried out.
Mathematical Model of a PM Brushless Motor with Different Stator-Rotor Pole Pairs Number
2013
The paper presents a mathematical model of Permanent Magnet AC brushless machines (PMSM) having a number of stator poles-obtained via the distribution of the three-phase winding- different from the rotor one, realized by the displacement of the permanent magnets. For these so- called ‘Fractional-Slot’ motors (where few total slots generate high equivalent number of poles) the available mathematical models appear partial and/or incomplete, despite of numerous designing considerations made in literature. In this paper an analytical approach is developed to point out an instantaneous- values mathematical model with concentrated parameters, that can be suitable for control architecture systems …