J.C. Viera

An Acoustic Resonance Band Detection Workbench for HID Lamps

This paper describes an automatic computer-controlled acoustic resonance detection workbench for high-intensity-discharge (HID) lamps. The detection method is based on optical measurements of the discharge arc path. With the aid of a dual lens projection system, relative light intensity measurements at different points of the arc are guided by fiber optic to a photodiode array. These measurements are statistically analyzed to identify when acoustic resonance occurs. Experimental results confirm this method to be a valuable tool to automatically obtain an acoustic-resonance-frequency map for HID lamps.

A new, reliable and easily implemented NiCd/NiMH battery state estimation method

This paper presents a new and reliable battery state estimation method for Ni-Cd and Ni-MH batteries used in portable applications. The proposed method performs the following two basic functions. The first one determines battery state, detecting deteriorated batteries. The second one guarantees a safe fast-charge without negative effects on battery life, analyzing the previous charge state of the battery. Due to this easily implemented method, effective and universal NiCd/NiMH battery fast-chargers can be obtained by using few and inexpensive components.

Comparison between Different Discharge Lamp Models Based on Lamp Dynamic Conductance

Discharge lamp models based on dynamic lamp conductance are derived from physical equations that describe lamp behaviour. Lamp constructive data are not necessary to build the models, just lamp current and voltage data are necessary. In addition, these models have a relatively low complexity and not much calculation time is necessary to obtain them. They can be used to simulate low and high pressure lamps at low and high (20 kHz < f < 1 MHz) frequencies. Two of these models, derived from different physical equations, are tested and compared using fluorescent and HPS Na lamps.

Measurement system for characterization of high intensity discharge lamps (HID) operating at high frequency

In this paper, a measurement system for characterization of High Intensity Discharge Lamps (HID) operating at high frequency is proposed. The measurement system provides a complete lamp characterization including acquisition of fundamental electrical parameters, an automatic method for acoustic resonance detection and lamp life testing capabilities. Also, a remote control and supervision of lamp operation is available.

Online SOC Estimation of Li-FePO4 Batteries through a New Fuzzy Rule-Based Recursive Filter with Feedback of the Heat Flow Rate

A new method for State of Charge estimation of LiFePO4 batteries through recursive filtering is presented. A fuzzy rule-based system is used to compute the nonlinear gain of the filter, and computational intelligence techniques are used to evolve the definition of the rule base. The estimation of the charge is based on a novel battery model that accurately predicts battery voltage and temperature. It will be shown that feeding back the difference between modelled and measured heat flow rates noticeably shortens the time needed to reach a correct estimation of the battery charge when initial conditions are unknown. An empirical study has been carried over data gathered at the Battery Laboratory at Oviedo University. The results show improvements in speed and stability. An accuracy of 95% was reached five times faster than linear filters with feedback of the cell voltage error.

Comparison Between Different Discharge Lamp Models Based on Lamp Dynamic Conductance

Discharge lamp models based on dynamic lamp conductance are derived from physical equations that describe lamp behavior. Lamp constructive data are not necessary to build the models, just the lamp current and voltage data are necessary. In addition, these models have a relatively low complexity, and not much calculation time is necessary to obtain them. They can be used to simulate low- and high-pressure lamps at low and high (20 kHz <; f <; 1 MHz) frequencies. Two of these models, derived from different physical equations, are tested and compared using fluorescent and high-pressure sodium lamps.

An intelligent instrumentation system for testing fast-charging process in high-capacity batteries

This paper describes a new system for testing fast-charge process in medium or high capacity batteries. The developed system integrates high-efficiency power stages (in order to implement different charging methods) and signal conditioning stages (main battery parameters are sampled to provide information about battery behavior). In this way, it is possible to study the efficiency of fast-charging methods. Due to the data obtained being processed and monitored online in a personal computer (both manual or automatic control of test is possible), different charge-end point detection methods can also be implemented.

Ratiometric Methods For Optical Fiber Instrumentation Based On Luminescence Sensors

The optical fiber instruments in analytical applications are usually based on a luminescence chemical sensor. Direct intensity measurements of the luminescence emission are, due to their simplicity, a very common measuring principle. Consequently, many optical fiber devices are based on the intensity measurement of the luminescence emission. Unfortunately, direct luminescent intensity measurements suffer from a series of non-analyte fluctuations, which make them inappropriate for the development of precise instrumentation. An alternative for solvents this trouble is to measure the lifetime of luminescence emission. In that case the drawback is an increase in the complexity of the measurement. A ratiometric measurement can solve many of the trouble previously exposed. When the excitation light interacts with a luminescence chemical sensor different optical emissions take place. Some of these emissions are analyte dependent and they are employed to extract the quantitative information required. The rest of emissions are usually considered like noise that can reduce the accuracy. With a ratiometric scheme this noise, or background light, is converted in a useful signal that can improve the accuracy of the measurement. In this paper we proposed two new ratiometric methods specially designed to be implemented with optical fiber instrumentation. The potential of our proposed ratiometric methods to overcome such problems of accuracy in luminescent sensing will be evaluated. The correct election of the methodologies with respect to the analytical performance of the chemical sensor will be also analyzed.

A Ratiometric Method for Oxygen Measurement Using a Luminescent Sensor

A great variety of methods for oxygen sensing using luminescent sensors have been proposed in recent years based on intensity or in lifetime quenching. Like lifetime measurements, ratiometric techniques are insensitive to the variations of the excitation light, optical path and photo-bleaching. In this work, we present a ratiometric method based on the phosphorescence-fluorescence spectral overlap emission of a phosphorescent chemical sensor. This dual emission makes ratiometric measurements possible without need of adding a reference luminophore. The ratio is calculated by measuring the phase shift between the excitation and the emission signal at two different frequencies. Theoretical aspects of the proposed methodology and the design and construction of a fiber-optical measuring system are discussed. Finally, the performance of the proposed measurement method has been assessed using the metal chelate Al-Ferron immobilized in an inorganic sol-gel support (an oxygen indicator which displays a strong fluorescence emission overlapping significantly with the measured phosphorescence emission)

Lithium-ion battery degradation indicators via incremental capacity analysis

Lithium ion battery (LIB) degradation originates from complex mechanisms, usually interacting simultaneously, and in various degrees of intensity. Due to its complexity, to date, identifying battery aging mechanisms remains challenging. To resolve such issue, various techniques have been developed, including in-situ incremental capacity (IC) and peak area (PA) analysis. The use of these techniques has been proved to be valuable for identifying LIB degradation, both qualitatively and quantitatively. In addition, due to their in-situ and non-destructive nature, the implementation of these techniques is feasible for onboard, battery management systems (BMS). However, the understanding and direct applicability of IC and PA techniques is not straightforward, as it requires the understanding of electrochemical and material science principles. Unfortunately, BMS design teams rarely include battery scientists, and are mainly composed of electrical engineers. Aiming to bridge gaps in knowledge between electrical engineering and battery science, here we present a set of direct look-up tables generated from IC analysis, that provides a simple tool for the evaluation of LIB degradation modes. We begin with a brief overview of the basics of IC and PA techniques and their relation to battery degradation modes, to later present the look-up tables, and conclude with various real-life examples of cell degradation, to illustrate the use of the look-up tables. This study exemplifies the use of look-up tables for BMS applications, providing a simple, fast and accurate real-time estimation of LIB degradation modes.