J. Pleite
Instituto de Salud Carlos III
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Publication
Featured researches published by J. Pleite.
IEEE Transactions on Power Electronics | 2004
A. Barrado; R. Vazquez; E. Olias; A. Lazaro; J. Pleite
This paper presents a theoretical and experimental study of the hybrid sources capabilities to improve both the dynamic response and the stability of switching power supplies. The hybrid sources are composed by both, a linear and a switching source connected in parallel. The reached improvements have been possible without affecting, significantly, the efficiency of the whole circuit. This solution is checked in low voltage sources. The obtained experimental results show that these power supplies present high dynamical performance, and therefore they can be used to feed digital signal processors and microprocessors.
ieee pes transmission and distribution conference and exhibition | 2002
J. Pleite; E. Olias; A. Barrado; A. Lazaro; J. Vazquez
Transformers are one of the main devices in the utility grids. Reliability, power quality, economic cost and even the company image are influenced by the transformers health. For this reason, advanced techniques have been developed in order to improve the transformer life assessment. FRA (frequency response analysis) techniques are nowadays widely used by the electric utilities as one of these advanced techniques. They are specially appreciated to detect winding displacements inside the transformer. The main problem about FRA techniques is to interpret the observed evolution of the frequency response in order to identify both failures and failures tendencies in the transformer. In order to solve this problem a modeling tool is proposed in this work using the frequency response measured at the transformer.
applied power electronics conference | 2004
A. Barrado; A. Lazaro; J. Pleite; R. Vazquez; J. Vazquez; E. Olias
Power supplies for last generation of microprocessors and DSPs must present low output voltage and fast transient response. The linear-non-linear control (LnLc control) was presented as a solution to improve the transient response in DC-DC buck converters. However, once the LnLc control has been analyzed, other important performances have been found such as, improving the stability of the system, improving the efficiency, reducing of the recovery time, making independent the bandwidth and the switching frequency; reaching all these performances with an easy implementation. In this paper, the features of the linear-non-linear control are described. It will be shown, how the LnLc improves the stability of a DC-DC buck converter modifying the open loop gain and phase as a function of the load current steps. To show this behavior the control transfer function (G/sub LnLc/) has been deduced. Several experimental results have been obtained in a synchronous rectifier buck converter to check its behavior. Thus, the novel LnLc control has been compared with the conventional voltage control under different conditions. Finally, the control transfer function has been obtained experimentally.
mediterranean electrotechnical conference | 2006
J. Pleite; C. Gonzalez; J. Vazquez; A. Lazaro
Power transformers are main devices in the performance of energy supply systems. Therefore, there is a great interest in its health state. Frequency response analysis (FRA) is nowadays an appreciated preventive technique used for transformer maintenance in order to detect winding displacements. But, in spite of the advantages of FRA, a systematic diagnosis procedure has not been still developed due to the physical meaning of the frequency response is not really obtained. Our research group has developed a three phase magnetic core model that provides the relations among the raw frequency response and the different parts inside the three phase transformer. Different effects of the magnetic core are recognized through different parameters of this model. A diagnosis procedure is available taking into account these parameters because the internal parts of the transformer are distinguished
power electronics specialists conference | 2002
A. Barrado; R. Vazquez; A. Lazaro; J. Pleite; E. Olias
Nowadays, one of the main challenges for power supplies designers is to feed the latest generation of microprocessors and DSPs, since they require high current slew rates together with low output voltage. In this paper, a novel control technique is presented to help the designers to comply with the current requirements. The proposed combined linear-nonlinear control (LnLC) scheme increases significantly the capability of conventional linear control to reduce the recovery time of the output voltage drop produced when a load current step occurs. Experimental results have been obtained for two cases: a synchronous rectifier buck converter, with a conventional voltage loop and the same converter with the novel LnLC. The comparison of these experimental results shows that, with the new control, the recovery time of the output voltage is reduced.
applied power electronics conference | 2003
A. Barrado; R. Vazquez; A. Lazaro; J. Pleite; J. Vazquez; E. Olias
A new alternative to get fast transient response DC/DC switching converters is presented in order to feed devices such as microprocessors and DSPs. The topology of the switching power supply is composed of two buck converters connected in parallel, each one of them with different aims, controlled by means of the linear-nonlinear control. In this paper, the LNL control is reviewed and applied to the proposed power supply (fast response double buck, FRDB). Also, experimental results are obtained to show the main features of the proposed converter and to compare them with the features of some other solution.
conference of the industrial electronics society | 2002
A. Lazaro; A. Barrado; J. Pleite; E. Olias
Single-stage power factor correction (PFC) AC/DC converters usually present a high storage capacitor voltage stress and voltage variation. The series inductance interval (SII) PFC converters allow obtaining a bulk capacitor voltage lower than the peak value of the line voltage and even lower than output voltage. In this paper the novel single-stage SII-B-2D PFC converter is presented. This topology combines as three main advantages a low value and not much variable storage capacitor voltage, input current harmonics under EN61000-3-2 Class D limits, and an advantageous component count.
IEEE Transactions on Power Electronics | 2004
A. Barrado; E. Olias; A. Lazaro; J. Pleite; R. Vazquez
In this paper, PWM-PD multiple output dc/dc converters are presented. Operation analysis and power block design are shown. Furthermore, a small-signal model is developed for the PWM-PD multiple output dc/dc converters working in continuous conduction mode. The control-block is presented and the closed-loop circuit performances, such as the line, load and cross regulation, are obtained analytically. Finally, experimental results for a PWM-PD converter, with three fully regulated outputs and with transformer, are shown.
applied power electronics conference | 2004
A. Lazaro; A. Barrado; J. Pleite; J. Vazquez; E. Olias
In order to feed a VRM from the AC line, several voltage-reduction steps are used. In this power chain, energy storage is required. This paper pretends to select the best voltage to store the energy and also to select the point in which to place the storage capacitor, looking for a reduction of the size and cost of this capacitor. To comply with this aim, two configurations of the power chain have been compared as well as different output voltages for each power block. The proposed analysis has resulted in some practical recommendations about how to handle the main factors, which determine the size and cost of the storage capacitors.
power electronics specialists conference | 1999
A. Barrado; E. Olias; A. Lazaro; R. Vazquez; J. Pleite
Multiple output DC/DC converters are commonly used in electronics equipment. These converters have typical problems such as line, load and cross regulations. The family of converters presented in this paper works at fixed switching frequency and it is characterized by using a combination between pulse width modulation and pulse delay control (PWM-PD), in order to reduce the number of regulator components in the converters. This control technique allows a bigger number of control parameters to be obtained than the number of controlled components. Finally, experimental results in a converter with three insulated outputs are presented.