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- 2018
- spectral irradiance
- correlated color temperature
- double monochromator
- color rendering index
- Uncertainty of measurement
- Measurement and Control Technology and Instruments
- Brno University of Technology
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Iolite Based Bulk Normalization as 100% (m/m) Quantification Strategy for Reduction of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Transient Signal
摘要： Iolite package draw more attention in laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) community in recent years due to its powerful data-handling capacity, excellent signal visualization and open source of calculation codes. In this study, the application of Iolite package was investigated for LA-ICP-MS elemental quantification, and a calculation code for the bulk normalization as 100% (m/m) strategy was compiled. We found that the spline interpolation approach was better than that of linear one for the correction of time-dependent instrument drift. BCR-2G as the quality material was used to assess the proposed code, and the results revealed that the code was practical and reliable. The analytical accuracy was influenced by the used calibration materials. TiO2, MgO, K2O and rare earth elements in BCR-2G were slightly off (5%–10%) when NIST SRM 610 as the calibrator. Cr and Mo were higher (10%–30%) than the recommended values when StHs6/80-G was used as the calibrator. The phenomena would be attributed to the matrix effect or the inaccurate values of corresponding calibrators. Three main sources for the LA-ICP-MS combined uncertainty were recognized, including the uncertainty of recommended values of analytes in calibration material, the uncertainty of measured intensity ratios in sample and the error in bulk normalization as 100% (m/m) strategy. A total of 50 elements in CGSG glass reference materials were quantified based on the proposed Iolite code. Major elements (except MnO, CaO and P2O5) matched well with the recommended values with a discrepancy of 5%, and the trace elements (except Cr, Ni, Zn, Ga, Mo and Sb) were agreement with the recommended values in 10%. The dataset reported in this study was helpful for the value certification of CGSG reference materials. Overall, the proposed Iolite code broadened the application of Iolite package in the reduction of LA-ICP-MS transient signal for the elemental determination.
关键词： CGSG reference material,Combined uncertainty,Laser ablation-inductively coupled plasma-mass spectrometry,Iolite package,Bulk normalization as 100% (m/m)
更新于2025-09-19 17:13:59
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Effect of Irradiance Measurement Sensors on the Performance Ratio of Photovoltaic Power Plant Under Real Operating Conditions: An Experimental Assessment in Turkey
摘要： The performance analysis of photovoltaic (PV) plants plays an important role in making investment decisions, creating more efficient designs, and in the operation and maintenance decisions in new plants. In addition, performance analysis provides a way to identify real-time operational problems and allows comparisons among different PV plants. Performance of PV plants can be indexed with many parameters, but service providers are giving energy guarantees according to their performance ratio (PR). There are many factors that affect PR, such as irradiation, temperature, wind speed, humidity and soiling. But, the most important factors affecting PR are irradiation and temperature. Hence, both the irradiation and the temperature must be measured correctly. Solar irradiation is usually measured with a pyranometer or reference cell. However, there are differences between the obtained data from these two sensors, which affects the PR significantly. In this study, the PR of an MW PV plant installed in Turkey was investigated. Two types of irradiation sensors (pyranometer and reference cells) and PVGIS program were used. The data were collected every 5 min during 1 year. The data passed through quality control and filtered process and some improper values were removed from the row data set. In addition, new data were written instead of the missing data. PR was calculated by using conventional and corrected method. As a result, the average annual PR is determined to be 81.05%, 79.04% and 78.96% and the corrected PR is determined to be 83.69%, 82.48% and 80.87% using the reference cell, pyranometer and PVGIS program, respectively.
关键词： Solar energy,Uncertainty of measurement sensors,Irradiance sensor,Corrected PR,Performance ratio (PR),Photovoltaic plant
更新于2025-09-16 10:30:52
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Adaptive Observer-based Control Strategy for Maximum Power Point Tracking of Uncertain Photovoltaic Systems
摘要： This work presents an adaptive observer-based control strategy for maximum power point tracking (MPPT) of uncertain photovoltaic (PV) systems. On the one hand, the PVG output voltage and/or current measurements are needed for MPPT techniques and controllers design and, on the other hand, the PV arrays have to be installed in a site that profits from good daily sunshine. This obviously leads to difficulty of PVG output current and voltage measurement if ever such a site is at great distance from the converter. Furthermore, the MPPT control accuracy could be significantly affected due to the cable parameters if only voltage and current measurements on the converter side of the cable are instead used. To overcome this issues, an adaptive extended Kalman–like observer providing estimates of PVG output current and voltage regardless of cable resistance and inductance deviations, is first designed. Afterwords, a backstepping controller is synthesized to ensure the MPPT objective. The designed adaptive observer-based MPPT control convergence is formally analyzed and its effectiveness in compensating for cable parameters uncertainties on the MPPT accuracy is validated through numerical simulations.
关键词： Photovoltaic,Adaptive extended Kalman like observer,Backstepping control,Uncertainty,MPPT
更新于2025-09-16 10:30:52
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Adaptive Extended Kalman–like Observer for Uncertain Photovoltaic Systems
摘要： The problem of state and parameter estimation in photovoltaic (PV) systems is addressed. The maximum power point tracking (MPPT) techniques and controllers design involve the PV generator (PVG) delivered voltage and current. However, in situations where PV arrays are located in a remote site from the control unit of the converter, so as to profit from good solar radiation, PVG voltage and current measurements become difficult. From other side, the use of long PV cable between the PVG and the converter would produce substantial voltage drops in the cable, which would consequently result in MPPT control inaccuracies if only voltage and current sensed in the converter input side of the cable are used instead. To avoid this problem, an adaptive Kalman–like observer for PV systems is designed, in this paper. Using only voltage and current measurements in the converter input, the observer performs online estimation of the PVG output voltage and current as well as of the cable resistance and inductance, regardless of these parameters uncertainties. The convergence of the system state and parameters is shown by simulation.
关键词： Photovoltaic,Adaptive extended Kalman like observer,Uncertainty,MPPT,Cable
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Development and Mass Production of Bifacial Q.ANTUM p-Cz PERC Cells
摘要： Cloud service providers are typically faced with three significant problems when running their cloud data centers, i.e., rising electricity bills, growing carbon footprints, and unexpected power outages. To mitigate these issues, running cloud data centers in smart microgrids (SMGs) is a good choice, since SMGs can enhance the energy efficiency, sustainability, and reliability of electrical services. Thus, in this paper, we investigate the problem of energy management for cloud data centers in SMGs. To be specific, we would minimize the time average expected energy cost (including electricity bill, battery depreciation cost, the total generation cost of conventional generators, and revenue loss due to the unfinished workloads) with the consideration of three practical factors, i.e., the ramping constraints of backup generators, the charging and discharging efficiency parameters of batteries, and two kinds of data center workloads. A stochastic programming is formulated by integrating the constraints associated with workload allocation, electricity buying/selling, battery management, backup generators, and power balancing. To solve the stochastic programming problem, an online algorithm is designed, and the algorithmic performance is analyzed. Simulation results show the advantages of the designed algorithm over other baselines.
关键词： energy cost,uncertainty,smart microgrids,Cloud data centers
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Dual-band tunable mid-infrared polarization converter based on U-shaped graphene metamaterial
摘要： 3-D coordinate transformation, which is based on aligning two sets of common reference points, is frequently applied in large-scale combined measurement to unify coordinate frames and tie individual measurement systems together. However, it introduces uncertainty into the ?nal measurement results. This uncertainty must be quanti?ed to make the results complete. This paper presents a novel approach to the uncertainty analysis of 3-D coordinate transformation based on the weighted total least squares adjustment. This approach takes full account of the uncertainty characteristics of measuring instruments and is simple in calculation. In this approach, the transformation uncertainty of a point in a world frame is analyzed carefully. The simulations show that the transformation uncertainty has a distribution of concentric ellipsoids and is affected by the measurement uncertainties and layout of common points. Besides, strategies for minimizing transformation uncertainty are recommended. The experimental results from a laser tracker prove that this proposed approach is valid under normal instrument operating conditions and that these strategies are feasible and ef?cient.
关键词： Coordinate transformation,error analysis,uncertainty,large-scale metrology,position measurement,sensor fusion
更新于2025-09-16 10:30:52
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Multipoint and energy-equal fiber-optic laser-ultrasonic actuator based on peanut-shaped structures
摘要： This paper introduces the parabolic variance (PVAR), a wavelet variance similar to the Allan variance (AVAR), based on the linear regression (LR) of phase data. The companion article arXiv:1506.05009 [physics.ins-det] details the Ω frequency counter, which implements the LR estimate. The PVAR combines the advantages of AVAR and modified AVAR (MVAR). PVAR is good for long-term analysis because the wavelet spans over 2τ, the same as the AVAR wavelet, and good for short-term analysis because the response to white and flicker PM is 1/τ3 and 1/τ2, the same as the MVAR. After setting the theoretical framework, we study the degrees of freedom and the confidence interval for the most common noise types. Then, we focus on the detection of a weak noise process at the transition—or corner—where a faster process rolls off. This new perspective raises the question of which variance detects the weak process with the shortest data record. Our simulations show that PVAR is a fortunate tradeoff. PVAR is superior to MVAR in all cases, exhibits the best ability to divide between fast noise phenomena (up to flicker FM), and is almost as good as AVAR for the detection of random walk and drift.
关键词： frequency stability,flicker,atomic frequency standard,Allan variance,phase noise,frequency noise,oscillator,measurement uncertainty
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Electrical and Computing Technologies and Applications (ICECTA) - Ras Al Khaimah, United Arab Emirates (2019.11.19-2019.11.21)] 2019 International Conference on Electrical and Computing Technologies and Applications (ICECTA) - Miniature Dual-Band Band-Pass Filter Using Slotted Ring Resonators and Coupled lines for L and S Bands Communication
摘要： This paper introduces the parabolic variance (PVAR), a wavelet variance similar to the Allan variance (AVAR), based on the linear regression (LR) of phase data. The companion article arXiv:1506.05009 [physics.ins-det] details the Ω frequency counter, which implements the LR estimate. The PVAR combines the advantages of AVAR and modified AVAR (MVAR). PVAR is good for long-term analysis because the wavelet spans over 2τ, the same as the AVAR wavelet, and good for short-term analysis because the response to white and flicker PM is 1/τ3 and 1/τ2, the same as the MVAR. After setting the theoretical framework, we study the degrees of freedom and the confidence interval for the most common noise types. Then, we focus on the detection of a weak noise process at the transition—or corner—where a faster process rolls off. This new perspective raises the question of which variance detects the weak process with the shortest data record. Our simulations show that PVAR is a fortunate tradeoff. PVAR is superior to MVAR in all cases, exhibits the best ability to divide between fast noise phenomena (up to flicker FM), and is almost as good as AVAR for the detection of random walk and drift.
关键词： atomic frequency standard,frequency noise,measurement uncertainty,oscillator,frequency stability,Allan variance,flicker,phase noise
更新于2025-09-16 10:30:52
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[IEEE 2019 24th Microoptics Conference (MOC) - Toyama, Japan (2019.11.17-2019.11.20)] 2019 24th Microoptics Conference (MOC) - Infrared LED Marker for Target Recognition in Optical Wireless Power Transmission to Moving Object at Dark Environment Condition
摘要： We investigate instantaneous transmission rate strategies for secondary users in cognitive radio networks by analyzing their effective capacity performance in different signal-to-noise ratio regimes with different quality-of-service constraints and transmission block sizes. Describing a channel model with one secondary transmitter and one secondary receiver with the potential presence of primary users, we present an interference power constraint that limits the transmission power of secondary users not only when a channel is sensed as busy but also when a channel is sensed as idle. Calling the existing transmission rate strategy Optimistic Policy, we introduce two other strategies, particularly Conservative Policy and Greedy Policy. Secondary users in Optimistic Policy set the instantaneous transmission rate to the instantaneous mutual information assuming the correctness of channel sensing results, whereas they set the instantaneous transmission rate to the instantaneous mutual information regarding possible transmission outages in Conservative Policy and disregarding possible transmission outages in Greedy Policy. We construct a state transition diagram and formulate the effective capacity employing these policies. We calculate the minimum energy-per-bit requirements and the high signal-to-noise ratio slope in order to explore performance variations in low and high signal-to-noise ratio regimes, respectively. Correspondingly, we show that Optimistic Policy is, in general, more favorable in secondary users when the quality-of-service constraints are loose, the transmission blocks are shorter, and the signal-to-noise ratio is low. On the other hand, Conservative Policy is better when the quality-of-service constraints are strict, the transmission blocks are longer, and the signal-to-noise ratio is high.
关键词： transmission rate,energy efficiency,minimum energy-per-bit,Cognitive radio,channel uncertainty,interference power constraints,effective capacity,channel sensing,high signal-to-noise ratio slope
更新于2025-09-16 10:30:52
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Techno-economic uncertainty quantification and robust design optimization of a directly coupled photovoltaic-electrolyzer system
摘要： To solve the problem of large time shifts between renewable energy supply and user demand, power-to-H2 is a well-known option. In this framework, previous studies have shown that the direct coupling of a photovoltaic array with an electrolyzer stack is a viable solution. However, these studies assumed perfectly known operating parameters to optimize the setup. Moreover, they focused on maximizing hydrogen and minimizing the energy loss, while the cost was not addressed. We have performed an optimization including uncertainty quantification (i.e. surrogate-assisted robust design optimization) for several locations with the Levelized Cost Of Hydrogen (LCOH) as objective. This paper provides the least sensitive design to uncertainties and shows which parameters are most affecting the variability of the LCOH for that design. The robust design optimization illustrates that the mean and standard deviation of the LCOH are non-conflicting objectives for the robust designs of all considered locations. The optimal robust design is established at the considered location with the highest average yearly solar irradiance, achieving a mean LCOH of 6.6 €/kg and a standard deviation of 0.72 €/kg. The discount rate uncertainty is the main contributor to the LCOH variation. Therefore, installing a PV-electrolyzer system in locations with a high average yearly solar irradiation is favorable for both the LCOH mean and standard deviation, while de-risking the technology has the highest impact on further reducing the LCOH variation. Future works will focus on including accurate probability distributions and adding batteries to the system.
关键词： Levelized cost of hydrogen,Photovoltaic-electrolyzer system,Uncertainty quantification,Robust design optimization
更新于2025-09-12 10:27:22