scholarly journals Noise Optimization Design of Frequency-Domain Air-Core Sensor Based on Capacitor Tuning Technology

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 194
Author(s):  
Shengbao Yu ◽  
Yiming Wei ◽  
Jialin Zhang ◽  
Shilong Wang
Keyword(s):  
Frequency Domain ◽  
Optimization Design ◽  
Signal To Noise Ratio ◽  
Experimental Tests ◽  
Impedance Analysis ◽  
Physical Structure ◽  
Normal Operation ◽  
Amplifier Circuit ◽  
Noise Current ◽  
Air Core

In the semi-aviation frequency-domain electromagnetic measurement, the induction air-core coil and the differential pre-amplifier circuit introduce noise, which affects the sensor and results in receiving weak signals and improving the signal-to-noise ratio of the system. In response to this problem, by analyzing the physical structure of the air-core coil sensor and the mechanism of the amplification circuit, combined with the simulation and experimental tests of voltage noise, current noise, resistance noise and other noise components, analyzed that the thermal noise is the main component of the sensor noise in the system frequency band, but directly removing the matching resistor increases the instability of the circuit, causes the coil to work in an underdamped state, and generates a time domain oscillation at the resonant frequency, source impedance analysis and analysis of differential pre-amplifier circuit in the frequency-domain detection method, abandoning the matching resistance scheme and magnetic flux negative feedback scheme. The matching capacitor is added to make the receiver detect the frequency range in the 1–10 kHz range. In normal operation, the noise level reaches 10 nV level, which not only increases the stability of the circuit, but also reduces the noise of the sensor. It has far-reaching significance for the detection of weak frequency signals.

scholarly journals A Novel Evaluation Method For Particle Deposition Measurement

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 927-934
Author(s):  
Tao Song ◽  
Chao Liu ◽  
Hengxuan Zhu ◽  
Min Zeng ◽  
Jin Wang
Keyword(s):  
Layer Thickness ◽  
Dielectric Layer ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Optimization Design ◽  
Turbine Blades ◽  
Simulation Software ◽  
Circuit Board ◽  
Normal Operation ◽  
Mass Detection

Abstract Normal operation of gas turbines will be affected by deposition on turbine blades from particles mixed in fuels. This research shows that it is difficult to monitor the mass of the particles deposition on the wall surface in real time. With development of electronic technology, the antenna made of printed circuit board (PCB) has been widely used in many industrial fields. Microstrip antenna is first proposed for monitoring particles deposition to analyse the deposition law of the particles accumulated on the wall. The simulation software Computer Simulation Technology Microwave Studio (CST MWS) 2015 is used to conduct the optimization design of the PCB substrate antenna. It is found that the S11 of vivaldi antenna with arc gradient groove exhibits a monotonous increase with the increase of dielectric layer thickness, and this antenna is highly sensitive to the dielectric layer thickness. Moreover, a cold-state test is carried out by using atomized wax to simulate the deposition of pollutants. A relationship as a four number of times function is found between the capacitance and the deposited mass. These results provide an important reference for the mass detection of the particle deposition on the wall, and this method is suitable for other related engineering fields.

scholarly journals A phase-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

2021 ◽  
Author(s):  
Baoling Guo ◽  
Seddik Bacha ◽  
Mazen Alamir ◽  
Julien Pouget
Keyword(s):  
Performance Analysis ◽  
Frequency Domain ◽  
Low Frequency ◽  
Experimental Tests ◽  
Frequency Measurement ◽  
Phase Locked Loop ◽  
Frequency Domain Analysis ◽  
Loop Filter ◽  
Control Stability ◽  
Unbalanced Grid

AbstractAn extended state observer (ESO)-based loop filter is designed for the phase-locked loop (PLL) involved in a disturbed grid-connected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra filters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PI-type PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the effectiveness of ESO-based PLLs when applied to the disturbed GcC.

scholarly journals Spectrum Sensing in Cognitive Radio using Frequency Domain

2019 ◽  
Vol 9 (2) ◽  
pp. 3475-3477
Keyword(s):  
Cognitive Radio ◽  
Frequency Domain ◽  
Spectrum Sensing ◽  
Bandwidth Allocation ◽  
Dynamic Spectrum Access ◽  
Signal To Noise Ratio ◽  
Wide Band ◽  
Energy Detection ◽  
Secondary Users ◽  
Sensing Applications

An efficient bandwidth allocation and dynamic bandwidth access away from its previous limits is referred as cognitive radio (CR).The limited spectrum with inefficient usage requires the advances of dynamic spectrum access approach, where the secondary users are authorized to utilize the unused temporary licensed spectrum. For this reason it is essential to analyze the absence/presence of primary users for spectrum usage. So spectrum sensing is the main requirement and developed to sense the absence/ presence of a licensed user. This paper shows the design model of energy detection based spectrum sensing in frequency domain utilizing Binary Symmetric Channel (BSC) ,Additive white real Gaussian channel (AWGN), Rayleigh fading channel users for 16-Quadrature Amplitude Modulation(QAM) which is utilized for the wide band sensing applications at low Signal to noise Ratio(SNR) level to reduce the false error identification. The spectrum sensing techniques has least computational complexity. Simulink model for the energy detection based spectrum sensing using frequency domain in MATLAB 2014a.

Design of a Force Feedback Chatter Control System

1972 ◽  
Vol 94 (1) ◽  
pp. 5-10 ◽  
Author(s):  
C. Nachtigal
Keyword(s):  
Machine Tool ◽  
Frequency Domain ◽  
Transient Response ◽  
Force Feedback ◽  
Design Procedure ◽  
Experimental Tests ◽  
Work Piece ◽  
Regenerative Chatter ◽  
Chatter Control ◽  
The Stability

The analysis of machine tool chatter from frequency domain considerations is generally accepted as a valid representation of the regenerative chatter phenomenon. However, active control of regenerative chatter is still in its embryonic stage. It was established in reference [2] that a measurement of the cutting force could be effectively used in conjunction with a controller and a tool position servo system to increase the stability of an engine lathe and to improve its transient response. This paper presents the design basis for such a system, including both analytical and experimental considerations. The design procedure stems from a real part stability criterion based on the work by Merritt [1]. Because of the unknown variability in the dynamics of a machine tool system, the controller parameters were chosen to accomodate some mismatch between structure and tool servo dynamics. Experimental tests to determine the stability zone of the controlled machine tool system qualitatively confirmed the analytical design results. The experimental results were consistent in that the transient response tests confirmed the frequency domain stability tests. It was also demonstrated experimentally that the equivalent static stiffness of a flexible work-piece system could be substantially increased.

scholarly journals Thermal and Electromagnetic Combined Optimization Design of Dry Type Air Core Reactor

Energies ◽  
2017 ◽  
Vol 10 (12) ◽  
pp. 1989 ◽  
Author(s):  
Fating Yuan ◽  
Zhao Yuan ◽  
Lixue Chen ◽  
Yong Wang ◽  
Junxiang Liu ◽  
...  
Keyword(s):  
Optimization Design ◽  
Air Core

scholarly journals Assessment of Micro-Organism Growth Risk on Filters with Machine Learning

2019 ◽  
Vol 111 ◽  
pp. 05017 ◽  
Author(s):  
Andreas Hantsch ◽  
Sabine Döge
Keyword(s):  
Machine Learning ◽  
Learning Algorithm ◽  
Signal To Noise Ratio ◽  
Visual Observation ◽  
Normal Operation ◽  
Health Issues ◽  
Filter Surface ◽  
Test Filter ◽  
Organism Growth ◽  
Electro Magnetic

Modern buildings usually have a practically air-tight envelope. Therefore, mechanical ventilation is very often necessary. A crucial part of the system is the filter which allows to create an atmosphere which is free of dust, aerosols, and pollen. As organic material accumulates on the filter surface, the risk of micro-organism growth rises. This may yield health issues especially for the occupants of buildings in humid regions. For this purpose, a test filter with electrodes has been designed which allowed to measure its electro-magnetic properties, such as resistance, capacitance, and impedance as an indicator for the micro-organism growth risk. After some preliminary tests, electrodes of stainless steel and the electrical capacitance have been selected due to their best durability and signal-to-noise-ratio. The test filter has been implemented in the HVAC system of the institute in order to aggregate data for different abnormal and normal operation data. A machine learning algorithm has been trained successfully to detect anomalies of the filter behaviour and therefore provided more insight than pressure drop measurement alone. Finally, the change intervals of the filter could be adapted to the real degree of pollution without the requirement for visual observation in order to provide best air conditions.

scholarly journals A Robust Real-Time Automatic Recognition Prototype for Maritime Optical Morse-Based Communication Employing Modified Clustering Algorithm

2020 ◽  
Vol 10 (4) ◽  
pp. 1227 ◽  
Author(s):  
Xiaozheng Wang ◽  
Minglun Zhang ◽  
Hongyu Zhou ◽  
Xinglong Lin ◽  
Xiaomin Ren
Keyword(s):  
Real Time ◽  
Clustering Algorithm ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Experimental Tests ◽  
Recognition Algorithm ◽  
Automatic Recognition ◽  
Decision Threshold ◽  
Low Snr ◽  
Led Array

In maritime communications, the ubiquitous Morse lamp on ships plays a significant role as one of the most common backups to radio or satellites just in case. Despite the advantages of its simplicity and efficiency, the requirement of trained operators proficient in Morse code and maintaining stable sending speed pose a key challenge to this traditional manual signaling manner. To overcome these problems, an automatic system is needed to provide a partial substitute for human effort. However, few works have focused on studying an automatic recognition scheme of maritime manually sent-like optical Morse signals. To this end, this paper makes the first attempt to design and implement a robust real-time automatic recognition prototype for onboard Morse lamps. A modified k-means clustering algorithm of machine learning is proposed to optimize the decision threshold and identify elements in Morse light signals. A systematic framework and detailed recognition algorithm procedure are presented. The feasibility of the proposed system is verified via experimental tests using a light-emitting diode (LED) array, self-designed receiver module, and microcontroller unit (MCU). Experimental results indicate that over 99% of real-time recognition accuracy is realized with a signal-to-noise ratio (SNR) greater than 5 dB, and the system can achieve good robustness under conditions with low SNR.

scholarly journals Design and Experiments of a Piezoelectric Motor Using Three Rotating Mode Actuators

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5184 ◽  
Author(s):  
Roland Ryndzionek ◽  
Łukasz Sienkiewicz ◽  
Michał Michna ◽  
Filip Kutt
Keyword(s):  
Numerical Analysis ◽  
Traveling Wave ◽  
Laser Interferometry ◽  
Experimental Tests ◽  
Impedance Analysis ◽  
Piezoelectric Motor ◽  
Resonant Frequencies ◽  
Rotary Motors ◽  
The Individual ◽  
Geometrical Dimensions

This paper represents a numerical and experimental investigation of the multicell piezoelectric motor. The proposed design consists of three individual cells that are integrated into the stator, double rotor, and a preload system combined into a symmetrical structure of the motor. Each of the cells is characterized by a traveling wave and rotating mode motor. A finite element numerical analysis is carried out to obtain optimal geometrical dimensions of the individual cell in terms of generated vibrations and resonant frequencies of the structure. The results of the numerical analysis are compared with analytical calculations based on the equivalent circuit theory. Experimental tests are also presented, including laser interferometry measurements of vibrations generated at the surface of the stator, impedance analysis, as well as measurements of mechanical characteristics of the complete motor. The final stage of the study concludes that the presented motor can provide relatively high torque compared with other traveling wave rotary motors.

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