The Experts below are selected from a list of 171168 Experts worldwide ranked by ideXlab platform
Thierry Schuller - One of the best experts on this subject based on the ideXlab platform.
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Chemiluminescence based Operating Point control of domestic gas boilers with variable natural gas composition
Applied Thermal Engineering, 2019Co-Authors: Yi Ding, Daniel Durox, Nasser Darabiha, Thierry SchullerAbstract:The current control strategy of domestic gas boilers optimizes the heating efficiency and pollutant gas emissions assuming a fixed fuel composition. However, larger and more frequent variations of gas composition are ex- pected in the European natural gas network. New control systems capable of monitoring and regulating the flame equivalence ratio in real time are therefore necessary. The present work investigates one equivalence ratio sensing strategy by analyzing the flame chemiluminescence signal from a laminar premixed burner widely used in domestic gas boilers. The OH∗ chemiluminescence intensity is first identified as a reliable equivalence ratio indicator, valid for different natural gas composition scenarios with CH4 diluted by N2 or CO2 or enriched by H2, C2H6 or C3H8. These fuel mixtures are representative of biogas and hydrogen enriched natural gas. A demonstrative control loop is developed based on the OH∗ signal measured by a photomultiplier tube mounted with a bandpass optical filter. The system is tested by changing the equivalence ratio set value and the fuel composition. It is shown to be capable of regulating the equivalence ratio of these natural gas fuel blends with a good precision. The differences observed between the real and target values for the equivalence ratio are in most cases lower than 0.01. Only fuel blends with C3H8 lead to slightly larger errors of 0.03.
Yi Ding - One of the best experts on this subject based on the ideXlab platform.
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Chemiluminescence based Operating Point control of domestic gas boilers with variable natural gas composition
Applied Thermal Engineering, 2019Co-Authors: Yi Ding, Daniel Durox, Nasser Darabiha, Thierry SchullerAbstract:The current control strategy of domestic gas boilers optimizes the heating efficiency and pollutant gas emissions assuming a fixed fuel composition. However, larger and more frequent variations of gas composition are ex- pected in the European natural gas network. New control systems capable of monitoring and regulating the flame equivalence ratio in real time are therefore necessary. The present work investigates one equivalence ratio sensing strategy by analyzing the flame chemiluminescence signal from a laminar premixed burner widely used in domestic gas boilers. The OH∗ chemiluminescence intensity is first identified as a reliable equivalence ratio indicator, valid for different natural gas composition scenarios with CH4 diluted by N2 or CO2 or enriched by H2, C2H6 or C3H8. These fuel mixtures are representative of biogas and hydrogen enriched natural gas. A demonstrative control loop is developed based on the OH∗ signal measured by a photomultiplier tube mounted with a bandpass optical filter. The system is tested by changing the equivalence ratio set value and the fuel composition. It is shown to be capable of regulating the equivalence ratio of these natural gas fuel blends with a good precision. The differences observed between the real and target values for the equivalence ratio are in most cases lower than 0.01. Only fuel blends with C3H8 lead to slightly larger errors of 0.03.
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Chemiluminescence based Operating Point control of domestic gas boilers with variable natural gas composition
'Elsevier BV', 2019Co-Authors: Yi Ding, Durox Daniel, Darabiha Nasser, Schuller ThierryAbstract:International audienceThe current control strategy of domestic gas boilers optimizes the heating efficiency and pollutant gas emissions assuming a fixed fuel composition. However, larger and more frequent variations of gas composition are ex- pected in the European natural gas network. New control systems capable of monitoring and regulating the flame equivalence ratio in real time are therefore necessary. The present work investigates one equivalence ratio sensing strategy by analyzing the flame chemiluminescence signal from a laminar premixed burner widely used in domestic gas boilers. The OH∗ chemiluminescence intensity is first identified as a reliable equivalence ratio indicator, valid for different natural gas composition scenarios with CH4 diluted by N2 or CO2 or enriched by H2, C2H6 or C3H8. These fuel mixtures are representative of biogas and hydrogen enriched natural gas. A demonstrative control loop is developed based on the OH∗ signal measured by a photomultiplier tube mounted with a bandpass optical filter. The system is tested by changing the equivalence ratio set value and the fuel composition. It is shown to be capable of regulating the equivalence ratio of these natural gas fuel blends with a good precision. The differences observed between the real and target values for the equivalence ratio are in most cases lower than 0.01. Only fuel blends with C3H8 lead to slightly larger errors of 0.03
Caroline Lelandais-perrault - One of the best experts on this subject based on the ideXlab platform.
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A Joint Crest Factor Reduction and Digital Predistortion for Power Amplifiers Linearization Based on Clipping-and-Bank-Filtering
IEEE Transactions on Microwave Theory and Techniques, 2020Co-Authors: Siqi Wang, Morgan Roger, Julien Sarrazin, Caroline Lelandais-perraultAbstract:The power efficiency and the linearity of a power amplifier (PA) depend on its Operating Point. A high efficiency generally corresponds to poor linearity. To optimize the efficiency/linearity tradeoff, crest factor reduction (CFR) techniques are classically implemented along with digital predistortion (DPD) to control the PA Operating Point. Joint CFR/DPD can be realized with a single model so that the running complexity of the CFR is negligible. This article fully explores the clipping-and-bank-filtering (CABF) method for joint CFR/DPD and extends it to the multicarrier case with validation of experimental results. Compared with conventional approaches, it provides either better linearization performance or lower complexity at the same PA Operating Point. The study is completed with a discussion on the choice of windows in the filter bank. The proposed CABF-based joint CFR/DPD model is then experimentally evaluated on a test bench with two PAs using single-carrier and two-carrier 20-MHz long-term evolution signals as the stimulus.
Saad Alghuwainem - One of the best experts on this subject based on the ideXlab platform.
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a close form solution for the maximum power Operating Point of a solar cell array
Solar Energy Materials and Solar Cells, 1997Co-Authors: Saad AlghuwainemAbstract:A solar cell array is inherently a nonlinear device consisting of several solar cell modules connected in series-parallel combinations to provide the desired DC voltage and current. At a fixed insolation level, the terminal voltage decreases nonlinearly as the load current increases. Due to this nonlinearity, it is difficult to determine analytically the Operating Point at which the output power is maximum; a condition required for maximum utilization efficiency of the array. Iterative techniques are normally used to determine this Operating condition. These techniques are lengthy, time-consuming, and have to be repeated for any change in the array's parameters, temperature, and insolation level. In this paper, an accurate closed-form solution is derived in terms of the array's parameters and solar insolation level. This solution is useful to the system designer or researcher as a fast and accurate tool for system design and performance analysis.
Martin Guay - One of the best experts on this subject based on the ideXlab platform.
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control and real time optimization of an automotive hybrid fuel cell power system
Control Engineering Practice, 2009Co-Authors: A Dalvi, Martin GuayAbstract:A real-time optimization method is used to find the Point of maximum fuel efficiency of a hybrid fuel cell power system, in an automotive application. The controller performs as the master control in cascade with lower level controls. The lower level controls distribute the power between the ultra-capacitor and the fuel cell, during transients, to find the optimum Operating Point of the power system. The ultra-capacitor is used to protect fuel cell health and improve phase characteristics of the system. In simulations, the controller is able to find the optimum Operating Point for the hybrid system without requiring previous knowledge of the system dynamics or explicit representation of the optimization function.
