Estimation Of Resonance Frequency Research Articles

Maximum Voltage Gain Tracking Algorithm for High-Efficiency of Two-Stage Induction Heating Systems Using Resonant Impedance Estimation

A boost power factor correction (PFC) circuit has replaced the diode rectifier to improve its poor power factor performance, low efficiency, and output power limitation for conventional induction heating (IH) applications. Accordingly, many studies have been conducted, but they considered only the efficiency of the boost PFC rather than the entire IH system, or their control and design were complicated. In this paper, an algorithm tracking the maximum voltage gain of the resonant network is proposed to improve the entire efficiency of the two-stage IH system based on an exact online resonant frequency estimation. It can make the resonant network operate at the maximum voltage gain point which can improve the efficiency of the series-resonant inverter (SRI) included in the IH system with low circulating current, the minimum switching frequency, and zero voltage switching (ZVS) capability. The proposed algorithm also induces the minimum output voltage of the boost PFC, which can reduce its switching losses and total harmonic distortion (THD). The validity of the proposed algorithm is experimentally verified using a 2.4-kW prototype IH system, including the boost PFC and the IH-SRI controlled by a digital signal processor (DSP).

A methodological approach to design a coil for localised high-frequency induction heating of flat plate

High-frequency induction heating (HFIH) is a quick heating technology, mostly used for localised surface treatment. The HFIH process has a portable RLC tank circuit consisting of a fixed size capacitor bank, load-matching transformer and a small size inductor coil. However, the work feasibility of small size inductor coil involves complexity in matching the resonant frequency between the RLC tank circuit and the high-frequency induction power source. Because the resonant frequency of the RLC tank circuit depends on the shape, size and configuration of the considered inductor coil. To address the issue, a numerical model-based approach is proposed herein to do the frequency matching for any coil configurations. Three different coil configurations such as co-direction, single-direction and opposite-direction current coils are considered in the simulation study to optimise their geometry and estimation of resonant frequencies. Based on the derived resonant frequency of the inductor coils, another coupled electromagnetic-thermal model is developed to get the thermal characteristics for a planar heating process of an 8 mm thick mild steel plate. After finding the optimal geometry of all coil configurations, the coils are fabricated and used in experimentation to verify the results of numerical models. It is found that the coil geometry has a significant effect on the resonant frequency and the heating characteristics. In addition, the current work emphasises a systematic approach to address the temperature non-uniformity that arises at the inlet and outlet positions of the workpiece in movable induction heating.

Estimation of Resonance Frequency for Systems with Contact Using Linear Dynamics Methods

Limitations in determining the resonance frequency for large models, taking into account non-linearity in the form of contact, initiated work on the creation of a simplified method of estimating these resonance frequencies. The trend in this field is the use of time-domain methods with full contact, or frequency-domain methods which take into account nonlinearity for specific cases. For simplification, classical modal analysis is often used, with boundary conditions taken into account or freeform vibrations, with neglected contact, or with tied contact areas, as though the contact was always closed. The presented approximation method is based on both types of such analysis and compensates for the error of both of the solutions. The method was elaborated with nonlinear dynamics simulations in the time domain. This work presents experimental verification of the method for a simple beam, and for more complex geometry—the satellite antenna panel.

Estimation of the Resonance Frequencies Using an Electrostatic Energy Based Capacitance Model of a Two-Winding Medium/High-Frequency Transformer

Being an integral part of many high-power converters, it is imperative to estimate the natural resonance frequencies of a medium/high-frequency (MF/HF) transformer. Experiment/measurement based methods reported in literature determine the resonance frequencies based on the input impedance measurements. However, their applications are limited if these resonance frequencies are to be estimated prior to the transformer prototyping. To ameliorate the drawback, this article provides a comprehensive modeling procedure for the winding capacitances of a two-winding transformer and its resonance frequency estimation. By integrating the prior capacitance modeling techniques, this article establishes an electrostatic energy based transformation model, which directly translates the static winding capacitances into equivalent model based capacitances. These derived capacitances are further utilized to represent a reduced <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\pi }$</tex-math></inline-formula> -model of a two-winding transformer, compute its frequency responses and estimate the resonance frequencies. The proposed model based approach is simple and easily executable, and helps avoiding any infeasible transformer design during the preprototyping stage. Experimental results derived from MF transformer prototypes, constructed of solid round, foil, and litz wires, are used to corroborate the theoretical analysis and feasibility of the proposed model based approach.

Piezoelectric resonator design and analysis from stochastic car vibration using an experimentally validated finite element with viscous-structural damping model

Within the Vibration Piezoelectric Energy Harvesting (VPEH) framework, this paper investigates and designs an optimal piezoelectric harvester (PH) under stochastic real-time vibrations using a step-by-step guideline from an electrical and mechanical perspective. A stochastic-excitation high-order-shear-deformation finite element (FE) method, with experimental verifications, analyzed the trapezoid non-uniform piezoelectric resonator under random base vibration. The significance of the contact layer and proper viscous-structural combined damping model is reported for precise power estimation. Based on modal sensitivity, a fast and effective model-updating method for structural modulation is developed. Parametric studies of the optimum load–frequency and natural frequency-geometrical parameters relationships are investigated. Modeling results indicate that ignoring the contact-layer effect will create inaccuracies in the resonant frequency estimation. Besides, a combined viscous-structural damping model is mandatory for proper resonant power estimation. The matched resistance loading is slightly different under stochastic vibration than the harmonic analysis. The presented method is applied on a real-time stochastic vibration, i.e., car vibration. Electrical power of 1.32 mW with density of 495.92 µW/cm3 are produced by installing one PH undergoing random excitation from gravity-direction. This power can be enough to power a low-power autonomous wireless vibration sensor demonstrating the VPEH usage in autonomous sensors for future intelligent cars.

Modeling the effects of modulated radiation pressure using a new acoustic lens

Modulated radiation pressure (MRP) is a method of utilizing the acoustic radiation force by using a double-sided suppressed carrier modulated (DSB-SCM) signal. This produces a modulated signal that oscillates at twice the modulation frequency. This process facilitates target detection and classification by using a high-carrier frequency to probe the target and shake it with the low-modulation frequency, which can be designed to be commensurate with the vibrational modes of the target. A frequency sweep can estimate the target resonant frequencies, while a physical scan along its length can estimate its mode shapes. Recently, a series of experiments were conducted at Washington State University with a newly designed and fabricated acoustic lens with a one-meter focal length. These experiments demonstrated that the first few bending modes of scaled targets like a solid aluminum cylinder and an open-ended aluminum cylindrical shell could be excited by MRP at a standoff distance of one meter and target mode shapes were measured using a physical scan. In this presentation, we show modeling results that confirm experimental findings: (1) estimation of target resonant frequencies using a frequency sweep and (2) estimation of target mode shapes using a physical scan.

Estimating the frequency and bandwidth of square-split ring resonator (S-SRR) designs via support vector machines (SVM)

In this study Support Vector Machine (SVM) based estimation technique is proposed for estimating the bandstop frequency and bandwidth of square-split ring resonators. Artificially engineered surfaces especially the planar frequency selective surfaces like the SRRs have narrowband properties so that estimating the filtering frequencies and the bandwidth is essential in a cost and design-effective way. The proposed method, which is superior to optimization methods and 3D electromagnetic solvers in terms of cost and computational burden, achieved accurate results via SVMs generalization capability. This study represents two SVM regression models one for predicting frequency and the other for predicting bandwidth having fast response and accuracy. Results of the proposed model reveal that resonance frequency estimation error, in terms of percentage, is bounded in the interval [0.0542, 3.5938], with an overall error of 0.89 % for the test data. The mean and standard deviation of the percentage error is obtained as 0.9861 and 0.9376, respectively. In addition to that -10dB bandwidth is estimated with the bounded error where estimation error in terms of percentage would be lie in the interval [0.068925, 6.876800] with an overall error of 3.68% for the test data.

Effect of Beam tunnels on Resonant Frequency of Cylindrical Reentrant Cavity

Analytical formulations for the resonant frequency of a reentrant cavity for klystron are available in the literature only for such cavities having a single beam-tunnel. An improved analytical formulation has been proposed in this paper for the calculation of cavity gap-capacitance of reentrant cavities having single and multiple beam-tunnels and its effects on the resonant frequency are studied. The results obtained through analysis have been validated against those obtained from the 3D electromagnetic field simulations and measurements. The proposed analytical formulation provides good estimation of resonant frequency of cavity with single and multiple beam-tunnels.

Robust estimation method of tire torsional resonance frequency to detect decrease in tire inflation pressure

Indirect tire pressure monitoring system monitors inflation pressures in pneumatic tires using wheel speed sensor (WSS) signals acquired from anti-lock braking system. In order to monitor the tire pressures indirectly, frequency analysis and wheel radius analysis are operating in parallel. This paper focuses on the frequency analysis. The resonance frequency of tire torsional vibration decreases as the tire pressure decreases. Therefore, the resonance frequency needs to be estimated to detect tire pressure decrease. This paper describes the resonance frequency estimation method with the WSS. Firstly, toothed wheel error of the WSS is calculated from the wheel speed signals and the wheel speed is corrected with the toothed wheel error. A notch filter is designed based on the engine rotational speed to eliminate the engine noise. The resonance frequency is estimated by model parameter estimation based on auto regressive model. Finally, compensation of the estimated frequency, detection of snow chain and monitoring of severe driving environments have been proposed to prevent false alarms at normal tire pressures. Vehicle tests have been conducted to evaluate the proposed estimation method of the resonance frequency. It has been shown that the proposed method provides satisfactory performance for warning indication of tire pressure loss from the test results.

Design and characterization of a buckling-resistant perforated MEMS membrane under residual stress

Micro Electro Mechanical Systems (MEMS) membranes are utilized as both transmitter and receiver in acoustic and ultrasound applications. Their operating frequency ranges are determined by their resonance frequencies. Thus, the resonance frequency estimation is one of the most critical parts of the membrane design. In this study, two perforated circular MEMS membranes are designed, microfabricated and characterized to get proper operation under residual stress since this stress might cause buckling of the membrane. Finite element methods (FEM) are applied and optical measurements are taken to extract the resonance frequencies. For the fundamental mode, the FEM results deviate 5.5% and 6.7% from the experimental work. 33.4% stress relaxation is achieved for the proposed perforated membranes. Furthermore, eight different circular membranes are simulated and compared with the analytical solutions. The minimum and maximum average percentage errors are acquired as 0.5% and 3.3% for the fundamental mode. The electrical characterizations are carried out with the impedance analyzer and results are supported by FEM. Stress was successfully managed with the help of the perforation as verified by the experimental work and simulations.

EM Modelling Considerations for mm-Wave On-Chip Antennas

We investigate the inaccuracy of resonant frequency (f0 ) estimation incurred by some common simplifications in electromagnetic (EM) simulation of mm-wave on-chip antennas. Using an 88 GHz patch antenna as a device under test (DUT), it is found that using a 2.5D planar EM solver produced highly inaccurate results. Including the bulk silicon and thin nitride in the model stack effected an improvement of 0.8% in estimating f0 , while replacing individually modelled via arrays with equivalent blocks, and accounting for the etch factor, marginally improved both the estimation of f0 and reflection coefficient |S11|. It is shown that, with the correct modelling choices, the error in f0 can be reduced to below 50 MHz at E-band, which is within the measurement variation of 880 MHz.

Experimental verification of resonance frequency estimation method in two-inertia system based on steady-state oscillation control

Experimental verification of resonance frequency estimation method in two-inertia system based on steady-state oscillation control

Fuzzy estimates of resonance frequencies for three-layer composite cylindrical panels in smart aerospace and industrial structures

Is developed a numerical-analytical fuzzy-sets methodic for a analysis of the uncertain endogenous parameters of the resonant frequencies in a theoretical model of vibration of thin orthotropic composite three-layer cylindrical panels with small curvature having of symmetrical structure with two external transversally-isotropic piezoelectric layers and with internal orthotropic layer from linearly viscoelastic composite material if available of scatter errors in values of their structural exogenous physical-mechanical and geometric parameters. The technique is based on the transition to fuzzy-interval arguments in the analytical representations for the studied resonant frequencies and in the application of the heuristic principle of generalization to obtain of estimates for the values of such resonant frequencies in the form of normal fuzzy sets. An example of the implementation of the technique under consideration is presented.

Cylinder pressure resonant frequency cyclic estimation-based knock intensity metric in combustion engines

This paper presents a knock intensity metric calculation method based on the in-cylinder pressure resonant frequency estimation to improve the quantification performance of knock phenomena. The knock intensity metric is defined as the mean energy over a specific frequency band with the estimated resonance frequency as the center position. The resonance frequency is estimated based on the precalibrated Bessel shifting factor and the online trapped mass estimation. Then, setting the estimated resonance frequency as the center point, the power spectral density of the pressure oscillation is calculated using the precalibrated pressure window over the precalibrated resonance frequency bandwidth. The proposed knock intensity metric is experimentally validated by comparison to the metric calculated over the frequency band of 6–25 kHz. The statistical analysis results show that the proposed metric exhibits a higher signal-to-noise ratio and is a more sensitive manner of knock quantification.

Learning to See the Vibration: A Neural Network for Vibration Frequency Prediction.

Vibration measurement serves as the basis for various engineering practices such as natural frequency or resonant frequency estimation. As image acquisition devices become cheaper and faster, vibration measurement and frequency estimation through image sequence analysis continue to receive increasing attention. In the conventional photogrammetry and optical methods of frequency measurement, vibration signals are first extracted before implementing the vibration frequency analysis algorithm. In this work, we demonstrate that frequency prediction can be achieved using a single feed-forward convolutional neural network. The proposed method is verified using a vibration signal generator and excitation system, and the result compared with that of an industrial contact vibrometer in a real application. Our experimental results demonstrate that the proposed method can achieve acceptable prediction accuracy even in unfavorable field conditions.

Investigation of microstrip‐fed low‐profile broadband circularly polarized rectangular dielectric resonator antennas

AbstractA microstrip‐fed low‐profile broadband circularly polarized rectangular dielectric resonator antenna (RDRA) suitable for WLAN applications based on IEEE 802.11.a standards was designed and tested. In addition, a new iterative method for the estimation of resonance frequency with the consideration of the effect of the substrate was investigated in this article. The RDRA exhibits broadband and circular polarization (CP) by utilizing the asymmetrical offset feeding mechanism to excite two orthogonal degenerate modes ( and ). The RDRA provides the impedance bandwidths (|S11| &lt; −10 dB) of 10.2% and the axial ratio (AR) bandwidth (AR &lt; 3 dB) of 1.8%. Good agreements between the simulated and measured results have been obtained.

Resonant frequency estimation for adaptive notch filters in industrial servo systems

This paper proposes a new algorithm for estimating the resonant frequency of adaptive notch filters used in servo systems. Notch filters and adaptive notch filters are widely used in commercial servo systems for suppressing a resonance which is a major obstacle in improving their performance. However, the conventional frequency estimation algorithm gives a dynamic behavior that is proportional to the difference between the square of the estimated frequency and the square of the actual frequency. This can cause the estimation dynamics to be too slow for low-frequency resonances, if both low- and high-frequency resonances are present and if the estimator gain is designed for a high frequency. This paper develops a new algorithm to give a dynamic behavior that is proportional to the difference in the estimated frequency and actual frequency. This allows selecting the estimation parameters independent from the value of resonant frequencies. The developed algorithm is implemented to a production servo controller and applied to a production printed-circuit-board inspection system. The experimental results show that the developed algorithm is much more effective in suppressing the resonances of both low- and high-frequencies, compared to the pervious algorithm. Furthermore, the ability to suppress vibration allows increasing the feedback gain, which in turn allows improving the tack time performance from 190ms to 100ms. All experiments reported in this paper were performed in an actual industrial environment using a production system, and the developed algorithms are applied to the production system.

Modeling of fluid resonance in-between two floating structures in close proximity

In this study, we conducted numerical simulations of fluid resonance in-between two floating structures based on potential theory assessing the effect of fluid viscosity by including the artificial damping force. The numerical results of two adjacent Barges systems and Barge & Wigley systems were compared with experimental data of those of the viscous fluid model based on Reynolds average Navier-Stokes equations (RANSE). It can be observed that the conventional potential flow model (without artificial damping force) significantly over-estimated the wave height and forces around the resonant frequencies. Results of the present method with an appropriate damping coefficient supported the available data, confirming the importance of the viscous damping effect on strong hydrodynamic interaction between the floating structures. Furthermore, influences of lateral clearances, wave heading angles, and ships’ motions on the wave surface elevations were analyzed. Validation and application of methods to estimate the fluid resonant frequencies and modes were also conducted. Generally speaking, Molin’s simplified theory can give an accurate estimation of resonant frequencies and serve as a practical tool to analyze the fluid resonant phenomena of gaps in-between a two Barge system and Wigley & Barge system in close proximity.

Dual-Peak Self-Biased Magnetoelectric Couplings in Tb&lt;sub&gt;0.3&lt;/sub&gt;Dy&lt;sub&gt;0.7&lt;/sub&gt;Fe&lt;sub&gt;1.92&lt;/sub&gt;/Pb(Zr,Ti)O&lt;sub&gt;3&lt;/sub&gt;/SmFe&lt;sub&gt;2&lt;/sub&gt; Symmetrical Multiferroic Heterostructures

A trilayer magnetoelectric (ME) composite consisting of a soft piezoelectric PZT-5H plate, a magnetostrictive Terfenol-D plate, and a rare-earth ferromagnetic Samfenol plate is fabricated and characterized for studies on the multipeak self-biased ME effects. In this symmetrical magnetostrictive/piezoelectric heterostructure, high shear-stress transfer to excite the bending resonance mode is induced by the magnetostrictive materials with opposite signs of magnetostriction, and a large internal anisotropic field is provided by a Samfenol plate due to its distinct ferromagnetism and magnetostriction. Consequently, hysteretic behavior can be simultaneously observed at both bending vibration resonance and transverse vibration resonance. Results demonstrate that the nonzero remnant ME coefficients of 0.7 and 2.23 V/Oe occur at bending frequency of 42.2 kHz and transverse frequency of 108.3 kHz, respectively, and the estimates of resonance frequencies are in agreement with the data. These characteristics provide the promise of this dual-peak self-biased symmetrical multiferroic heterostructure for low frequency magnetic field detection without the benefit of additional permanent magnets.

Acoustic Estimation of Resonance Frequency and Sonodestruction of SonoVue Microbubbles

AbstractAcoustic properties of ultrasound (US) contrast agent microbubbles (MB) highly influence sonoporation efficiency and intracellular drug and gene delivery. In this study we propose an acoustic method to monitor passive and excited MBs in a real time. MB monitoring system consisted of two separate transducers. The first transducer delivered over an interval of 1 s US pulses (1 MHz, 1% duty cycle, 100 Hz repetition frequency) with stepwise increased peak negative pressure (PNP), while the second one continuously monitored acoustic response of SonoVue MBs. Pulse echo signals were processed according to the substitution method to calculate attenuation coefficient spectra and loss of amplitude. During US exposure at 50–100 kPa PNP we observed a temporal increase in loss of amplitude which coincided with the US delivery. Transient increase in loss of amplitude vanished at higher PNP values. At higher PNP values loss of amplitude decreased during the US exposure indicating MB sonodestruction. Analysis of transient attenuation spectra revealed that attenuation coefficient was maximal at 1.5 MHz frequency which is consistent with resonance frequency of SonoVue MB. The method allows evaluation of the of resonance frequency of MB, onset and kinetics of MB sonodestruction.