Search results for "Multilevel"

Social Emotional Competence, Learning Outcomes, Emotional and Behavioral Difficulties of Preschool Children: Parent and Teacher Evaluations

2022

This paper addresses the role of social emotional competence in the emotional and behavioral problems and learning outcomes of preschool children based on their parents’ and teachers’ evaluations. In this study, we compared the perceptions of teachers and parents when evaluating the same child using the multi-informant assessment. First, the associations and differences between both the informant evaluations were investigated. Second, the correlation of the social emotional competence and emotional, and behavioral difficulties among preschool children was analyzed, separately addressing their parents’ and teachers’ evaluations. Third, the role of the preschool children’s social emotional co…

Experimental Evaluation of Dead-Time Impacts on the Efficiency and THD for a Three-Phase Five-Level Cascaded H-Bridge Inverter

2022

Cascaded H-Bridges Multilevel Inverter (CHBMI) is a fascinating solution for optimization purposes in several application fields. The CHBMI performance optimization can be reached both with hardware and software solutions. In detail, the CHBMI performances are a function of the modulation strategy adopted and its parameters such as modulation index, switching frequency, and dead time. This paper presents performance experimental analysis on dead time effects on CHBMI performance in terms of harmonic distortion and conversion efficiency. In this analysis, two different modulation strategies have been considered and implemented. The paper focuses on modulation strategies implemented, the test…

Cascaded H-Bridges Multielvel Inverters: grid connected advanced applications

Power electronics is going to increase in the modern electrical systems. It is well known that the use of power electronics allows the management and the control of the energy flow, obtaining voltage and current waveforms suitable for electrical loads. In this scenario, multilevel power converters are finding increased attention in industry and academia as one of the promising choices of electronic conversion thanks to their features and many different application fields with high power and medium voltage. Moreover, they are fundamental in interfacing electric grid to high power renewable energy systems (i.e. PV, Wind farm, Biomass, Fuel Cell etc.). Nowadays, the research is focused on the …

A novel method for harmonic mitigation for single-phase five-level cascaded H-Bridge inverter

2018

The efficiency of a system is a very important parameter for high power electrical drives applications. Moreover, the efficiency of power converters plays a fundamental role. Aim of this work, is to propose a novel selective harmonic mitigation method without solving non-linear equations. Through a very simple approach, the polynomial equations which drive the control angles have been detected for a single-phase five-level cascaded H-Bridge inverter. The obtained polynomial equations can be easily implemented in a digital system to real-time operation. The paper also presents the simulation analysis and experimental validation.

Enhanced Modelling for Extended Performance Analysis of Interior Permanent Magnet Synchronous Machine Drive fed with Cascaded H-Bridges Multilevel In…

2021

This paper presents a comparative simulation analysis of an Interior Permanent Magnet Synchronous Machine (IPMSM) performance once fed by a traditional three-phase two-level inverter and then using a three-phase five-level Cascaded H-Bridges Multilevel Inverter (CHBMI). For this purpose, an enhanced mathematical model of the IPMSM, that take into account simultaneously saturation, cross-coupling, spatial harmonics and iron loss effects, has been employed. Furthermore, two different PWM modulation strategies have been considered. The study was conducted for several working conditions, evaluating the impact of CHBMI adoption on the IPMSM performance in terms of improved efficiency and torque …

Mothers' abusive childhood predicts child abuse

1999

To examine the intergenerational transmission of abuse, the study compared 25 mothers whose child had been under the supervision of the child protection services (CPS) with 25 mothers who had had no contact with the CPS. The groups were compared with respect to their own self-reported childhood abuse, their abuse of their own child and punitiveness. The data were gathered using interviews and files. There were no significant differences between the groups in self-reported childhood physical abuse, but the CPS mothers had experienced more childhood psychological abuse, especially rejection, accusations, terrorizing and corrupting. The groups did not differ in the self-reported physical or ps…

When Violence Can Appear With Different Male Partners: Identification of Resilient and Non-resilient Women in the European Union

2018

Introduction: Little scholarly attention has been paid to the analysis of the history of intimate partner violence (IPV) against women with different male partners and how it could be related to levels of IPV with the current male partner. From this point of view, been a victim of IPV could increase the vulnerability of women and, therefore, exert a negative influence on the selection of partners over time, thus increasing the odds of potentially mating with abusive male partners. Alternatively, for some women victims of IPV in previous relationships, there may be additional resources that reduce their vulnerability to victimization by new partners. Methodology: The present study analyzes l…

Self-worth contingencies and obsessionality: A promising approach to vulnerability?

2012

Abstract Cognitive behavioral theories (CBT) posit deficiencies in selfhood processes as possible vulnerability factors for obsessive–compulsive disorder (OCD). This paper presents two psychometric studies on the development of the Obsessional Concerns and Self Questionnaire (OCSQ), a measure of failure to attain self-worth in personal domains relevant to obsessionality. In the first study based on 563 community Spaniards, principal factor analysis of an 80 item pool resulted in a three factor solution and a final 35 item version (OCSQ-r). In the second study self-worth and symptom measures were administered to 152 Spanish, 142 Argentinean and 112 Canadian nonclinical samples. Group compari…

Compromiso afectivo, liderazgo participativo e innovación del empleado: una investigación multinivel

2019

Research investigating the relationship between organizational affective commitment and employee innovation has yielded scarce and inconsistent findings. This study examined the role of participative leadership in a team as a boundary condition of the effectiveness of organizational affective commitment predicting employee innovation. Data were collected from 343 employees in 34 teams from different Italian companies. The results from hierarchical linear modelling analysis indicated that the relationship between organizational affective commitment and employee innovation was stronger when team-level participative leadership was high. Our findings provide meaningful insights regarding the co…

A Novel Symmetrical Boost Modulation Method for qZS-based CHB Inverters

2020

Quasi-Z-source cascaded H-bridge (qZS-CHB) inverters are arising as an innovation in the field of the electrical conversion for PV applications. This type of converters inherit the advantages of multilevel inverters and single-stage configuration. In this context, this paper proposes a novel symmetrical boost modulation strategy for qZS CHB multilevel inverters to increase the performance in terms of voltage stresses and power quality. The novelty lies in the adoption of a different concept to generate the shoot-through states compared to the traditional methods. Simulation analysis in a grid connected application to evaluate the benefits of this boost method is performed in the MATLAB/PLEC…