27 research outputs found
Spacecraft magnetic attitude control using approximating sequence Riccati equations
This paper presents the results of a spacecraft attitude control system based on magnetic actuators designed for low Earth orbits. The control system is designed by using a nonlinear control technique based on the approximating sequence of Riccati equations. The behavior of the satellite is discussed under perturbations and model uncertainties. Simulation results are presented when the control system is able to guide the spacecraft to the desired attitude in a variety of different conditions
New space vector modulation algorithms applied to multilevel converters with balanced DC-link voltage
This work presents a survey of new space vector modulation algorithms for high power voltage source multilevel converters. These techniques provide the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. These algorithms drastically reduce the computational load maintained permitting the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors. The on-state durations are reduced to a simple addition. In addition, the low computational cost of the proposed methods is always the same and it is independent of the number of levels of the converter. The algorithms have been satisfactorily implemented in very low-cost microcontrollers.Ministerio de Ciencia y Tecnología DPI 2001-308
High Technology Readiness Level Techniques for Brushless Direct Current Motors Failures Detection: A Systematic Review
Many papers related to this topic can be found in the bibliography; however, just a modest
percentage of the introduced techniques are developed to a Technology Readiness Level (TRL)
sufficiently high to be implementable in industrial applications. This paper is focused precisely on
the review of this specific topic. The investigation on the state of the art has been carried out as
a systematic review, a very rigorous and reliable standardised scientific methodology, and tries to
collect the articles which are closer to a possible implementation. This selection has been carefully
done with the definition of a series of rules, drawn to represent the adequate level of readiness of
fault detection techniques which the various articles propose.Unión Europea (7PM / 2007-2013) / ERC n. 78533
Reducing Conducted Emissions at the Output of Full-Bridge DCDC Converters with High Voltage Steps
In this work, we analyze the impact of output filter design techniques aimed to reduce
conducted emissions at the output of a DCDC power converter. A thorough analysis, based on
high-frequency circuit models of the converter, is performed to assess expected improvements offered
by different design strategies. This analysis is then confronted with measurements of conducted
emissions at the output of a 300 W 48 V to 12 V Phase Shift Full Bridge (PSFB) prototype. Those
experimental results demonstrate that a symmetric arrangement of the output LC filter and a direct
bonding of the return output terminal of the converter to chassis are effective to reduce common
mode conducted emissions at the output. Those results also demonstrate that the symmetry of the
output LC filter can reduce conducted emissions in differential mode at high frequencies, where
common mode to differential mode conversion is the predominant contribution to differential mode
noise. However, direct bonding to chassis of the return output terminal may be ineffective at high
frequencies due to the parasitic inductance associated with this connection. Main conclusions drawn
for this analysis are applicable in general for isolated converters with a high voltage step between
high and low voltage sides. Since the techniques of reduction of conducted emissions studied here
do not increase the number of filter components, they are especially suitable for applications where
high power density is an important requirement, e.g., aerospace or automotive applications.Ministerio de Economía y Competitividad de España TEC2014-54097-RUnión Europea H2020-EU.3.4.5.6
Effective modulation algorithm for three-level converters
This paper presents an effective modulation algorithm (EMA) for high power voltage source three-level converter. This approach drastically reduces the computational load maintained, being substituted by decision making. This method permits the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors corresponding to the modulation of a three-level inverter. Therefore stored information from a memory or a table is not necessary in EMA. The modulation method used in this work presents the advantage of eliminating the angle from the calculations. This modulation technique permits an economic and simply electronic implementation
Space Vector Modulation Techniques for Multilevel Converters – a survey
This paper presents a survey of most recent,
simple and efficient Space Vector Modulation algorithms
for multilevel converters. These algorithms avoid
trigonometric and other complex operations, leading to
more simple and cost efficient implementations. They can be
applied to multilevel topologies and present freedom degrees
that can be Exploited in order to optimize system
parameters in the system like: capacitors voltages balancing
or voltage/current ripples. Experimental results are
presented to show the good performance of the algorithms
Proposal for a EU quality label for aerospace education
The paper presents a possible roadmap for the definition of a European quality label for aerospace related higher education degrees. The proposal is the result of a two-years long Horizon 2020 project that has involved a great portion of the European stakeholders in aerospace: Universities, research centres, industries (both small and large) networks, associations and accreditation agencies. The core concept established is that it is possible to establish a sector-specific, content based, quality system, that can complement the existing national or European accreditation systems, providing added value to the internal and/or external quality assurance processes that are in place in most EU countries. The tools and processes proposed are sufficiently simple to be manageable by Universities in addition to their national accreditation processes or as stand-alone assessment. The main goal of the proposed process is the evaluation of the quality of the aerospace curricula in the European context, whereas the accreditation of the programme can be seen as an optional extension of the process, subject to further national regulations. The process is proposed in view of the awarding of a sector-specific, content based, quality label, to be issued by an appropriate legally recognized and qualified institution. 8 field tests with volunteering universities throughout Europe have been performed. They experienced the method as very practical and to the point.Unión Europea H2020 64021
Simple Setup for Measuring the Response to Differential Mode Noise of Common Mode Chokes
This work presents a technique to measure the attenuation of differential mode noise
provided by common mode chokes. The proposed setup is a simpler alternative to the balanced
setup commonly employed to that end, and its main advantage is that it avoids the use of auxiliary
circuits (baluns). We make use of a modal analysis of a high-frequency circuit model of the common
mode choke to identify the natural modes actually excited both in the standard balanced setup and
in the simpler alternative setup proposed here. This analysis demonstrates that both setups are
equivalent at low frequencies and makes it possible to identify the key differences between them
at high frequencies. To analyze the scope and interest of the proposed measurement technique we
have measured several commercial common mode chokes and we have thoroughly studied the
sensitivity of the measurements taken with the proposed setup to electric and magnetic couplings.
We have found that the proposed setup can be useful for quick assessment of the attenuation provided
by a common mode choke for differential mode noise in a frequency range that encompasses the
frequencies where most electromagnetic compatibility regulations impose limits to the conducted
emissions of electronic equipment.Ministerio de Economía y Competitividad TEC2014-54097-RMinisterio de Economía y Competitividad H2020-EU.3.4.5.6SCOPUS project ID 83194
A novel space-vector algorithm for multilevel converters based on geometrical considerations using a new sequence control technique
his paper presents a fast and simple space vector modulation algorithm for voltage source multilevel converters for calculating the switching times and the space vectors using simple geometrical considerations. This method provides the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. The low computational cost of the proposed method is always the same and it is independent of the number of levels of the converter. In addition, a new switching sequence control technique is presented for reducing the ripple of the DC-link voltage approximately in 66%
Multilevel Converters: An Enabling Technology for High-Power Applications
| Multilevel converters are considered today as the
state-of-the-art power-conversion systems for high-power and
power-quality demanding applications. This paper presents a
tutorial on this technology, covering the operating principle and
the different power circuit topologies, modulation methods,
technical issues and industry applications. Special attention is
given to established technology already found in industry with
more in-depth and self-contained information, while recent
advances and state-of-the-art contributions are addressed with
useful references. This paper serves as an introduction to the
subject for the not-familiarized reader, as well as an update or
reference for academics and practicing engineers working in
the field of industrial and power electronics.Ministerio de Ciencia y Tecnología DPI2001-3089Ministerio de Eduación y Ciencia d TEC2006-0386