3,014 research outputs found
LC compensators for power factor correction of nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples
LC compensators based on transmission loss minimization for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThis paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes
The limits of inclusion? Exploring the views of Roma and non Roma in six European union member states
No full textThis final research report for the Roma SOURCE project presents an analysis of new qualitative data generated in 24 focus groups with members of both Roma and non Roma populations resident in the six Member States in which the Roma SOURCE partners are situated (i.e. Bulgaria, Greece, Hungary, Italy, Spain and the United Kingdom). It builds on the literature and policy review previously presented in anearlier interim report which combined contextual discussions on the general situation of Roma in Europe with more specific information (drawn from the ‘country reports’ compiled by Roma SOURCE project partners), about the particular circumstances of Roma populations in those six Member States (rf. Brown, Dwyer and Scullion, 2012). A key aim of the fieldwork which underpins this final report was to access, and make sense of, a range of views and opinions about the extent to which Roma and non Roma people believed they routinely led segregated or integrated lives
“Should we exit before Brexit?” Hungarian workers’ experiences & future plans in post-referendum Britain
No full textGrowing concerns over the large influx of Central and Eastern European migrant workers to the UK since the enlargement of the EU in 2004 played a major role in the result of the EU Referendum in June 2016. Now, in the era of Brexit, when millions of EU citizens are in a limbo and uncertain about their future rights here in the UK, it is the right time to explore their experiences and highlight the perceived impacts of Brexit on migrant workers’ lives. Previous research mainly focused on CEE migrants’ workers labour market experiences prior to the Referendum. Moreover, most of these studies recruited Polish participants, as they are the single largest group from the CEE region in the United Kingdom. Contributing to this gap, the present research, employed a qualitative approach to explore Hungarian workers’ labour market pre- and post- Referendum experiences and trajectories in the context of Brexit. As such, ten semi-structured interviews were conducted and subsequently analysed, using thematic analysis. The focus of the analysis was directed toward the individual experiences of participants and the perceived impact of Brexit on their experiences and future plans in the United Kingdom. Detailed discussion of the findings is presented under four master themes: “Motivations to Migrate”; “Upward mobility within the labour market”; “Making sense of the result”; and “Impacts and Future Intentions”. Limitations and strengths of the study, alongside with suggestions for future research are considered in the final chapter
Cost-effective applications of power factor correction for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2005 IEEEThe objective of this paper is to propose a new approach for designing passive LC compensators by using the penalty function method as an optimization tool. The performance of the cost-effective passive LC compensator for a constant load depends on the appropriate inductor and capacitor selection. Several design methods are reviewed and a novel design methodology is proposed in this paper. By using the proposed method, the designer can quickly find appropriate parameter values to meet the desired circuit performance. Simulated results show that an appropriate combination of the inductor and capacitor selected by the proposed method can meet the desired power-quality requirement. Different cases of design examples are shown in this paper to verify the performance of the proposed design methodology
A 155W −95.6 dB THD+N GaN-based Class-D Audio Amplifier With LC Filter Nonlinearity Compensation
No full textSilicon MOSFETs-based medium-power (< 50W) Class-D amplifiers (CDAs) switching in the MHz range have gained popularity in recent years, which achieves better linearity thanks to a higher loop gain in the audio band while enabling the use of LC filters with higher cut-off frequencies. However, for high-power (>100 W) CDAs, such switching frequency and high load current could lead to significant power loss. Furthermore, in the presence of a large current and voltage applied to the load, the linearity of the system can quickly degrade due to LC filter component voltage/current dependency. Without any LC filter nonlinearity compensation technique, LC components with high voltage/current rating must be used to reach high system linearity, which are often expensive and bulky. This paper presents a CDA using a GaN-based output stage to achieve high switching frequency and good efficiency simultaneously, and an integrated controller implemented in a 180nm CMOS technology to compensate for the LC filter nonlinearity. Switching at 1.8 MHz, the CDA can deliver a maximum of 155W from a 50V supply into a load with a peak efficiency of 91.7%. It achieves a peak THD+N of −95.6 dB (0.0017%) while allowing the use of cheaper and smaller nonlinear LC components.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and MaterialsMicroelectronic
A - 121.5-dB THD Class-D Audio Amplifier With 49-dB LC Filter Nonlinearity Suppression
No full textClass-D audio amplifiers produce electromagnetic interference (EMI), which often needs to be suppressed by an external LC filter. However, due to component nonlinearity, this filter can itself cause significant distortion. This article presents a class-D amplifier that suppresses LC filter nonlinearity by 49 dB and is robust to ±30% variations in its cutoff frequency. This is achieved by a dual-loop architecture, in which an inner loop provides stability, while an outer loop provides the high gain needed to suppress the LC filter and output-stage nonlinearity. A prototype, implemented in a 180-nm BCD process, achieves -121.5-dB total harmonic distortion (THD) and -107.1-dB THD+N, which is maintained to within 3 dB even as the LC filter cutoff frequency is varied from 62 to 106 kHz. It can deliver a maximum of 21 W into a 4-Ω load with 87% efficiency and 12 W into an 8-Ω load with 91% efficiency, measured at 10% THD. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Sanctuary to sanction : asylum seekers, refugees and welfare conditionality in the UK
No full textSuccessive UK Governments have introduced a raft of legislation that has reducedthe level of support for asylum seekers, whilst simultaneously attaching conditionsto the receipt of this support. While refugee status brings people into the mainstreamwelfare system and provides them with similar rights as UK citizens, very little isknown about how they experience the conditionality and sanctions inherent withinthis system. Drawing upon new data from longitudinal interviews with refugees,this paper explores their experiences of navigating the mainstream social securitysystem and raises questions about the ethicality of the application of conditionalityfor forced migrants
Central and Eastern European migrants in Daventry andSouth Northamptonshire : Developing a profile : Final report
No full textThis report presents the findings of a study exploring Central and Eastern European migrants in Daventry and South Northamptonshire. The study was commissioned by Daventry and South Northamptonshire Local Strategic Partnerships (LSPs) Migration Impact Funding and was conducted by researchers from the Salford Housing & Urban Studies Unit (SHUSU) at theUniversity of Salford. The study was managed by a steering group composed of officers representing Daventry District and South Northamptonshire Councils
Women Asylum Seekers and Refugees: Opportunities, Constraints and the Role of Agency
No full textThis article is based on the findings of research undertaken towards a doctoral thesis funded by the University of Leeds. The research focuses upon the actions and experiences of women asylum seekers and refugees living inWest Yorkshire. While acknowledging that the context in which women find themselves can present a number of barriers, this paper looks at their actions and practices at the individual and collective levels. It illustrates that some women are able to draw on the resources available, and are engaged in activitiesthat not only assist their own settlement in the host society but also assist the development of support structures for future arrivals of asylum seekers and refugees
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