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- 摘要
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An Alternative Formulation for Optimum TMD Parameters Based on Equal Eigen Value Criteria
摘要： Closed form expressions for optimum Tuned Mass Damper (TMD) parameters are obtained by equating Eigen values of two modes and there is no need of any trial and error approach as used in earlier studies. For certain values of damping of main system and mass ratio, two sets of optimum parameters exist. For some other range of damping and mass ratio, modes become fully damped. In this range, optimum TMDs do not exist, and this happens for TMDs with large mass. The optimum TMD is shown to be quite robust and gives lesser TMD displacement as compared to optimum TMDs of earlier studies.
关键词： Equal modal frequency,Equal Eigen Value,Fully damped modes,Frequency response function,Optimum Tuned Mass Damper,Equal modal damping
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Power & Energy Society General Meeting (PESGM) - Portland, OR, USA (2018.8.5-2018.8.10)] 2018 IEEE Power & Energy Society General Meeting (PESGM) - Experimental Determination of PV Inverter Response to Grid Phase Shift Events
摘要： With the continued growth of renewable energy resources which interface to the electric grid via inverters, the understanding of such devices becomes ever more important to the safe and reliable operation of the bulk power system. This work investigates the specific response of a utility-scale PV inverter to grid voltage phase shift-type disturbances which sometimes occur during grid fault events. The role of the PV inverter’s phase-locked-loop (PLL) is identified as important to modeling the response. Switching-level simulations of a utility-scale PV inverter with a modeled PLL show a characteristic response when phase shift disturbances require the PLL to track what appear as fast frequency changes. Additionally, in this work a full-scale laboratory testing was carried out using the Opal real time (RT) OP5142 real time simulator and a large grid simulator to create phase shift disturbances with a high degree of repeatability. A photovoltaic (PV) inverter was connected to a grid simulator, and phase shifts were instantaneously implemented on the simulated grid, the results of the currents were then obtained. The experimental results obtained were validated with simulation results obtained from MATLAB/Simulink.
关键词： frequency response,photovoltaics,phase-locked loops,harmonics,inverter,DER
更新于2025-09-23 15:23:52
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Damage degree prediction method of CFRP structure based on fiber Bragg grating and epsilon-support vector regression
摘要： The assessment of structural damage is of great significance for ensuring the service safety of carbon fiber reinforced plastics (CFRP) structures. In this paper, the damage degree prediction method of CFRP structure based on fiber Bragg grating and epsilon-support vector regression was studied. The structural dynamic response signals were detected by fiber Bragg grating sensors. Then, the Fourier transform was used to extract the dynamic characteristics of the structure as the damage feature, and the damage feature dimensionality was reduced by using the RReliefF algorithm. On this basis, the damage degree prediction model of CFRP structure based on epsilon-support vector regression was established. Finally, the method proposed in this paper was experimentally verified. The results showed that the epsilon-support vector regression model can accurately predict the damage degree of unknown samples, and the absolute relative error of 27 experiments was less than 10% for 30 testing experiments. This paper provided a feasible method for predicting the damage degree of CFRP structures.
关键词： Frequency response,Carbon fiber reinforced plastics,Epsilon-support vector regression,RReliefF,Damage degree prediction
更新于2025-09-23 15:23:52
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Engineering organic electrochemical transistor (OECT) to be sensitive cell-based biosensor through tuning of channel area
摘要： The barrier integrity of epithelial tissue is crucial to many physiological functions in multicellular organisms. Hence, several scientific techniques, such as epithelial voltohmmeter (EVOM) and electric cell-substrate impedance sensing (ECIS), were developed to assess barrier function for in vitro assays. Organic electrochemical transistor (OECT), in particular, outperforms many biosensors because of its multiple advantages such as high transconductance, mixed ionic-electronic conductivity and high biocompatibility. Despite its extensive application in cell impedance sensing, little was reported on how its geometrical dimensions would affect the device performance and quality of cell-based measurement. In this work, OECTs in different dimensions were fabricated and characterized. Specifically investigated were their time and frequency responses towards the presence of epithelial cells (i.e. tightly packed colorectal adenocarcinoma cell line caco-2 and a novel leaky nasopharyngeal carcinoma cell line NPC43). Results show that the sensitivity of cell-based measurement is closely related to the impedance of the whole cell-OECT system. The performance of cell-based sensor would be affected by the tightness of target cell and can be tuned by controlling the active area of OECT.
关键词： Conducting polymer,Frequency response,Biosensor,Impedance spectroscopy,Transepithelial electrical resistance,Organic electrochemical transistor
更新于2025-09-23 15:23:52
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Application of FRA to Improve the Design and Maintenance of Wireless Power Transfer Systems
摘要： Frequency response analysis (FRA) plays an important role in the assessment of the mechanical integrity and hence, reliability of high-voltage power transformers. Wireless power transfer (WPT) system introduced by Tesla a 100 years ago based on Faraday’s law of electromagnetic induction is similar to a conventional power transformer. Therefore, the reliability of a large WPT system can also be evaluated using FRA measurement. When the WPT system is constructed, the electrical components and the desired transfer distance need to be ascertained accurately. Furthermore, the structure of the winding and the electrical characteristic of the components in WPT systems may vary due to aging or fault events. FRA measurement can examine the discrepancy between the WPT system parameters and the reference fingerprint data to provide cost-effective condition monitoring-based maintenance scheme for the WPT systems. This paper presents a detailed circuit analysis of a two-coil inductively coupled WPT model in different compensating topologies to accomplish efficient energy transfer. Then, FRA measurement is used to detect the variation in the amplitude and the phase angle of the developed circuit input impedance in a wide frequency range. In addition, displacements due to the placement of ferrite material and the variation of the transfer distance between the transmitter and receiver units are investigated through practical measurements.
关键词： RLC resonance,inductive power transfer (IPT),Frequency response analysis (FRA),wireless power transfer (WPT)
更新于2025-09-23 15:22:29
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Design of Microstrip Bandpass Filters Based on Stair-Step Patch Resonator
摘要： In this research article, single pole bandpass filter using stair-step patch topology based on symmetrical and asymmetrical step impedance resonators has been designed for industrial, scientific and medical (ISM) band application. This filter has been modeled by Microwave Office simulator using RT/Duroid substrate constant of 10.8, the substrate thickness of 1.27mm, loss tangent of 0.0023 and copper metallization thickness of 0.035 mm. To enhance the stopband levels of filter response, two microstrip bandpass filters have been designed as two-pole configurations based on edge, and cross-coupled stair-step patch resonators using the same simulator tool and substrate specifications. The proposed filters have compact sizes of (0.311λ(cid:2917)(cid:2925) x 0.233λ(cid:2917)(cid:2925)) for single pole filter, (0.578λ(cid:2917)(cid:2925) x 0.24λ(cid:2917)(cid:2925) )for two-pole edge coupled filter and (0.566λ(cid:2917)(cid:2925) x 0.234λ(cid:2917)(cid:2925))for two-pole cross-coupled filter designed at center frequencies of 2.4, 2.46 and 2.41 GHz respectively. These filters have interesting insertion loss and return loss magnitudes, narrow band frequency responses, second harmonic suppression and good stopband levels. Apart from ISM band applications, the proposed filters can be adopted in WLAN systems and Bluetooth applications for short range devices. The experimental results for designed filters are of good consistency with the simulations.
关键词： ISM band applications,stair-step patch resonator,filter compactness,narrow band frequency response,Microstrip bandpass filters,second harmonic frequency blocking
更新于2025-09-23 15:21:21
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[IEEE 2019 8th International Conference on Power Systems (ICPS) - Jaipur, India (2019.12.20-2019.12.22)] 2019 8th International Conference on Power Systems (ICPS) - Primary Frequency Response Constrained Energy Storage Scheduling Under Photovoltaic Generation
摘要： Variable demand pattern with the large-scale photovoltaic (PV) integration poses a challenge for the system operator to maintain demand-generation balance. This imbalance would lead to events of frequency deviations. The initial frequency deviation can be counteracted by system inertia (SI) and primary frequency response (PFR). However, due to decline in frequency response on PV integration causes more events of frequency deviations, following contingencies like generation loss. This decline in system response necessitates additional sources of PFR. Energy storage system (ESS) due to its high power capacity and fast response time could be a viable alternative for PFR. In this context, the paper proposes to scrutinise the potential of ESS in controlling frequency under large-scale PV integration. New England 39 bus system is used to demonstrate the efficacy of the proposed. Simulation results show the ESS potential for PFR adequacy under PV integration. Moreover, the results demonstrate the reduction in system operation cost and PV curtailment.
关键词： rate of change of frequency,system inertia,primary frequency response,Energy storage systems,PV curtailment
更新于2025-09-23 15:21:01
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Frequency Response Function Based Updating of a Laser Spot Welded Structure using Synthesised Frequency Response Function
摘要： Accurate analytical models of engineering structures are of paramount importance for dynamicists to be used in predicting the dynamic behaviour (frequency response function) of the structures. The finite element method (FEM) and the experimental modal analysis (EMA) have been known as powerful and useful methods that can be used to determine the frequency response function (FRF) of the structures. However, the finite element FRF are often not in good agreement with experimental FRF due to assumption properties in finite element (FE) model. Therefore, in order to have a reliable FE model of a structure, measured FRF obtained from the experimental modal analysis can be integrated with finite element FRF to reconcile the FE model and the procedures involved in the reconciliation is a model updating process. Prior performing the updating process, the experimental FRF must be in good quality to obtain accurate FE model results. One way to reduce noise data and eliminate suspicious modes in FRF data is to use the FRF synthesised method. The main goal of this study is to use frequency response function based updating to minimise the error of a laser spot welded structure by using FRF synthesised data. In this work, MSC Software and LMS Test Lab were used to predict and measured the FRF of laser spot welded structure. The results revealed that FRF based updating method is successfully reduced the correlation gap between synthesised FRF and predicted FRF.
关键词： frequency response function,synthesised FRF,model updating,laser spot weld
更新于2025-09-23 15:21:01
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[Lecture Notes in Electrical Engineering] Engineering Vibration, Communication and Information Processing Volume 478 (ICoEVCI 2018, India) || Performance Optimization of Self-exited Piezoelectric Vibration Sensor
摘要： Performance evaluation of self-exited piezoelectric vibration sensor with respect to dimensions, shape and material are carried out in the present paper, with an objective to ?nd the design and dimension for which we get optimum performance in terms of frequency response and sensitivity. A new design is proposed based on the parameters discussed, for design COMSOL tool is used. Response for the designed vibration sensor for variation in frequency, with varying dimensions is performed for both differential and lateral loads. Results obtained give us information regarding the operating load, bandwidth, power, voltage and current ranges for best performance.
关键词： Piezoelectric,Optimization,Frequency response,Vibration
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Lausanne (2018.7.29-2018.8.2)] 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Selective Infiltration Damping of MEMS Scanning Mirrors
摘要： Quasi-static MEMS scanning mirrors are used for optical beam steering on arbitrary trajectories. They have to provide a broad mechanical bandwidth depending on the desired speed. In this work an approach by passive damping of the MEMS mirrors with gel droplets is described, that allows to increase the usable bandwidth. In order to achieve this, a dielectric gel is dispensed into the mirrors' structure. The appropriate infiltration method is presented. Static and dynamic properties such as maximum tilt angle and frequency response are investigated. Furthermore the reduction of parasitic effects like the coupling of the two axes of the mirror is discussed.
关键词： damping,frequency response,viscoelastic gel,scanning mirror,MEMS
更新于2025-09-23 15:21:01