Showing papers on "Sine wave published in 2022"

A Modified Seven-Level Inverter with Inverted Sine Wave Carrier for PWM Control

Abstract: The conventional multilevel inverter necessitates more active switching devices and high dc-link voltages. To minimalize the employment of switching devices and dc-link voltages, a novel topology has been proposed. In this paper, a novel minimum switch multilevel inverter is established using six switches and two dc-link voltages in the proportion of 1 : 2. In addition, the proposed topology is proficient in making seven-level voltages by appropriate gate signals. The PWM signals were produced using several inverted sine carriers and a single trapezoidal reference. When compared to other existing inverters, this configuration needs fewer components, as well as fewer gate drives. Furthermore, this module can generate a negative level without the use of a supplementary circuit such as an H-Bridge. As a result, overall cost and complexity are greatly reduced. The proposed minimum switch multilevel inverter operation is validated through simulations followed by experimental results of a prototype.

Dynamic Temperature Modulation Measurement of VOC Gases Based on SnO2 Gas Sensor

Abstract: Pure SnO2 is widely used to detect VOC gases due to its high stability. Unfortunately, there is a problem of poor selectivity, especially for gases such as ketones and alcohols, which have a similar high sensitivity. In this paper, dynamic temperature modulation technology was used to solve this problem. Rectangular wave and sine wave, typical voltage jump waveform and voltage smooth waveform, were used as heating voltage waveform. It was introduced in detail that the optimization of dynamic temperature modulation parameters based on response time and power consumption. According to the different heating waveform parameters, we obtained the dynamic response data of six groups of sensors to five concentration gradients of acetone, butanone, n-propyl alcohol and isopropyl alcohol. It was used to evaluate the performance of heating waveform parameters by support vector machine (SVM) and principal component analysis (PCA) combined with K-nearest neighbor (KNN) algorithm. Both data analysis methods showed that the recognition effect was better when the SnO2 sensor was heated by sine wave. In order to reduce power consumption, the heating waveform was determined as 0-6 V sine wave. Then the mechanism was analyzed in dynamic temperature modulation of the sensor. The voltage smooth waveform reached the stepless response of multiple temperature points by traversing the temperature range. More characteristics can be produced by experiencing more types proportion of adsorbed oxygen species within the cycle. It provided a new research idea for semiconductor gas sensor dynamic temperature modulation technology.

Resonance of a structure with soil elastic waves released in non-linear hysteretic soil upon unloading

Abstract: Abstract High-frequency motion is often observed in small-scale experimental works carried out in flexible containers under simplified seismic loading conditions when single harmonic sine input motions are introduced at the base of a soil specimen. The source of the high-frequency motion has often been sought in experimental inaccuracies. On the other hand, the most recent numerical studies suggested that high-frequency motion in the steady-state dynamic response of soil subjected to harmonic excitation can also be generated as a result of soil elastic waves released in non-linear hysteretic soil upon unloading. This work presents an example of a finite element numerical study on seismic soil–structure interaction representative of an experimental setup from the past. The results show how high-frequency motion generated in soil in the steady-state response, apparently representative of soil elastic waves, affects the steady-state response of a structure, that is, it is presented how the structure in the analysed case resonates with the soil elastic waves. The numerical findings are verified against the benchmark experimental example to indicate similar patterns in the dynamic response of the structure.

Dependence of Functional Parameters of Sine-Gated InGaAs/InP Single-Photon Avalanche Diodes on the Gating Parameters

Abstract: In this paper, we investigateda self-developed sine wave gated single-photon detector (SPD) for 1550 nm wavelength primary for quantum key distribution (QKD) usage. We studied the influence of DC bias voltage and AC gate amplitude on the SPD’s functional parameters and presented a simple and effective algorithm for its optimization. Such optimization showed practical benefits while SPD was set up on the QKD device. We admitted that the dark count rate decreases with an increase in gating voltage with fixed photon detection efficiency. We observed the charge persistence effect in sine-gated SPDs, which previously had been observed only at square-pulses gated SPDs, and showed that this effect is limiting for infinity increasing gate amplitude.

Multi-Sine EIS for Early Detection of PEMFC Failure Modes

Abstract: Electrochemical impedance spectroscopy (EIS) is a powerful technique that can be used to detect small changes in electrochemical systems and subsequently identify the source of the change. While promising, analysis is often non-intuitive and time-consuming, where collection times of a single EIS spectrum can reach several minutes. To circumvent the long collection times associated with traditional EIS measurements, a multi-sine EIS technique was proposed in which the simultaneous application of many frequencies can reduce the acquisition time to less than a minute. This shortened acquisition time opens the possibility to use multi-sine EIS as a real-time diagnostic tool for monitoring the state-of-health of commercial fuel cell systems. In this work, a single-cell proton exchange membrane fuel cell (PEMFC) was characterised using multi-sine EIS, by establishing steady-state impedance response under baseline conditions before systematically changing operating conditions and monitoring the dynamic changes of the impedance response. Our initial results demonstrate that full multi-sine EIS spectra, encompassing a frequency range from 50 kHz to 0.5 Hz, can be collected and analysed using simple equivalent circuit models in 50 s. It is shown that this timeframe is sufficiently short to capture the dynamic response of the fuel cell in response to changing operating conditions, thereby validating the use of multi-sine EIS as a diagnostic technique for in-situ monitoring and fault detection during fuel cell operation.

The Optimal Sine Pulse Frequency of Pulse Hydraulic Fracturing for Reservoir Stimulation

Abstract: Pulse hydraulic fracturing (PHF) is a key technique for reservoir stimulation. PHF can well accelerate the rupture of rock. However, the supercharging mechanism of PHF is not fully understood. The main reason is that the pressure distribution and its variation, especially the peak pressure characteristics, are unclear inside the pipe and fissure. The present research focuses on the sine pulse applied at the inlet of a pipe or fracture to reveal the variation regularity of peak pressure with the pulse frequency, amplitude, pipe length, diameter and wave speed. First, the weakly compressible Navier–Stokes equations were developed to simulate the variation of fluid pressure. The computation codes were developed using the MacCormack method validated by the existing experimental data. Then, the sine pulse effect was studied inside the pipe and fissure. Last, a new frequency model was built to describe the relationship between the optimal pulse frequency, wave speed and pipe length. The results show that there is a family of frequencies at which the peak pressure of the endpoint can be significantly enhanced and that these frequencies are the optimal pulse frequency. It is found that the optimal pulse frequency depends on the pipe or fissure length and wave speed. At the optimal pulse frequency, the peak pressure at the endpoint can be increased by 100% or more, and the cavitation phenomenon occurs. However, the peak pressure decreases when with the decrease in the pipe diameter and fissure departure due to the friction drag effect of the wall. These new landmark findings are very important for the PHF technique. In addition, a new universal frequency model is built to predict the optimal sine pulse frequency. The present research shows the variation regularity of the fluid pressure inside the pipe and develops a sine frequency-controlled method, providing a potential guide for reservoir stimulation.

SinLU: Sinu-Sigmoidal Linear Unit

Abstract: Non-linear activation functions are integral parts of deep neural architectures. Given the large and complex dataset of a neural network, its computational complexity and approximation capability can differ significantly based on what activation function is used. Parameterizing an activation function with the introduction of learnable parameters generally improves the performance. Herein, a novel activation function called Sinu-sigmoidal Linear Unit (or SinLU) is proposed. SinLU is formulated as SinLU(x)=(x+asinbx)·σ(x), where σ(x) is the sigmoid function. The proposed function incorporates the sine wave, allowing new functionalities over traditional linear unit activations. Two trainable parameters of this function control the participation of the sinusoidal nature in the function, and help to achieve an easily trainable, and fast converging function. The performance of the proposed SinLU is compared against widely used activation functions, such as ReLU, GELU and SiLU. We showed the robustness of the proposed activation function by conducting experiments in a wide array of domains, using multiple types of neural network-based models on some standard datasets. The use of sine wave with trainable parameters results in a better performance of SinLU than commonly used activation functions.

Pulse width research on half-sine excitation signal for bending vibrator

Abstract: Acoustic well logging adopts bending vibrators to transform high-voltage electric signals into acoustic signals. Excited acoustic signals have been proven best when the pulse widths are $0.5/{f_0}$ (${f_0}$ refers to the resonance frequencies of the bending vibrator). However, acoustic logging uses transformers to improve the excitation power, and these transformers change the rectangular excitation signals into similar half-sine signals. We study the relationships between the pulse widths of the similar half-sine excitation signals and the characteristics of the excited acoustic signals. Finite element analyses are performed to investigate the displacements of the center node on the surface of the piezoelectric ceramics that are excited by the pulse signals of different widths. Then, we design a circuit to realise the rectangular and half-sine excitation signals. Subsequently, acoustic experiments are carried out in our sound-deadening water tank to certify the simulation results. Results indicate that the best pulse width is $0.75/{f_0}$.

Coupled Inductor Based Bidirectional Resonant Converter With Sine Wave Modulation in Wide Voltage Range

Abstract: This letter proposes a coupled inductor based bidirectional series resonant converter (CIBSRC). In addition, a sine-wave modulation (SWM) with fixed frequency is also proposed to achieve load independent voltage gain for wide voltage range. The proposed CIBSRC integrates a boost stage and a resonant stage by a coupled inductor which replaces boost inductor, resonant inductor, and high frequency transformer. Compared with the bidirectional integrated resonant topologies, the number of magnetic components is less. Under proposed SWM, only one set of pulsewidth modulation signal is needed and zero voltage switching (ZVS) of all switches could be realized. Besides, the resonant current is a sine-wave which can simplify ZVS analysis and reduce current harmonics. A 500-W prototype with 100–200 V input voltage and 360 V output voltage was built and the results proved the reliability and validity.

Focused surface acoustic wave induced nano-oscillator based reservoir computing

Abstract: We demonstrate using micromagnetic simulations that a nanomagnet array excited by surface acoustic waves (SAWs) can work as a reservoir. An input nanomagnet is excited with focused SAW and coupled to several nanomagnets, seven of which serve as output nanomagnets. To evaluate memory effect and computing capability, we study the short-term memory (STM) and parity check (PC) capacities, respectively. The SAW (4 GHz carrier frequency) amplitude is modulated to provide a sequence of sine and square waves of 100 MHz frequency. The responses of the selected output nanomagnets are processed by reading the envelope of their magnetization states, which is used to train the output weights using the regression method. For classification, a random sequence of 100 square and sine wave samples is used, of which 80% are used for training, and the rest are used for testing. We achieve 100% training and 100% testing accuracy. The average STM and PC are calculated to be ∼4.69 and ∼5.39 bits, respectively, which is indicative of the proposed acoustically driven nanomagnet oscillator array being well suited for physical reservoir computing applications. The energy dissipation is ∼2.5 times lower than a CMOS-based echo-state network. Furthermore, the reservoir is able to accurately predict Mackey-Glass time series up to several time steps ahead. Finally, the ability to use high frequency SAW makes the nanomagnet reservoir scalable to small dimensions, and the ability to modulate the envelope at a lower frequency (100 MHz) adds flexibility to encode different signals beyond the sine/square waves classification and Mackey-Glass predication tasks demonstrated here.

Effect of gaps/overlaps induced waviness on the mechanical properties of automated fiber placement (AFP)-manufactured composite laminate

Abstract: Automated Fiber Placement (AFP) process is widely used to produce lightweight composite components owing to its excellent flexibility and efficiency. However, the out-of-plane fiber waviness induced by gaps and overlaps inevitably formed in the AFP process lack experimental studies. Therefore, an experimental research is proposed to study the influence mechanism of out-of-plane fiber waviness. Herein, based on the description of the shape of the fiber waviness, the relationship between the magnitude factor and the axial elastic modulus of laminate with fiber waviness is established. By embedding gaps and overlaps in the layup, a new approach to manufacturing composite laminate with fiber waviness of sine wave and sine-like wave is proposed, and the rationality of the theoretical analysis on the elastic properties of laminate with fiber waviness is verified. Finally, the effect of the magnitude factor on the mechanical properties of composite laminate is obtained by tensile and compression test. Experimental results show that the tensile and compression properties of laminate decrease significantly with the increase of magnitude factor. The effect of sine-like wave on mechanical properties is similar to that of sine wave, and it is feasible to splice sine-like wave into sine wave for mechanical property analysis.

Periodic traveling wave, bright and dark soliton solutions of the (2+1)-dimensional complex modified Korteweg-de Vries system of equations by using three different methods

Abstract: In this paper, the (2+1)-dimensional complex modified Korteweg-de Vries (cmKdV) equations are studied using the sine-cosine method, the tanh-coth method, and the Kudryashov method. As a result, analytical solutions in the form of dark solitons, bright solitons, and periodic wave solutions are obtained. Finally, the dynamic behavior of the solutions is illustrated by choosing the appropriate parameters using 2D and 3D plots. The obtained results show that the proposed methods are straightforward and powerful and can provide more forms of traveling wave solutions, which are expected to be useful for the study of the theory of traveling waves in physics.

Low-Cost Multi-Frequency Eddy Current Coating Thickness Measurement System

Abstract: A low-cost coating thickness gauge based on Eddy Current Testing (ECT) is reported in this paper. This measurement system employs a Direct Digital Synthesizer (DDS) to generate pure sinusoidal stimulus applied to a measurement coil whose impedance varies with the measured coating thickness. The coil current and voltage are digitally acquired using an ARM Cortex M4F microcontroller where sine-fitting digital signal processing algorithms are applied to estimate the coil inductance and resistivity at different operation frequencies. Post-processing implements a simple multi-frequency estimate algorithm providing accuracy improvements around 10% when compared with the use of a single frequency.

Multiple Sine-Wave Superposition Drive for the Doubly Salient Motor Based on Fourier Linearization Modeling

Abstract: Doubly salient motor (DSM) is a new type of high-speed motor. For aeronautics applications, DSM has a nonsinusoidal nonlinear structure and is driven by the square-wave current. As a result, the driving of DSM is hard to be quantitatively designed and optimized. This article proposes a multiple sine-wave superposition (MSWS) driving method that generates current waveforms composed of fundamental component and harmonic components with specific amplitudes and initial phases. That is based on a new accurate DSM Fourier linearization modeling, completely different from present square-wave driving methods of DSMs. In this article, a simplified linear relation between the current and the torque harmonic component is established. Then, a tradeoff between torque-to-current ratio and torque ripple is made. As a result, the optimal current waveforms of maximum torque-per-ampere and torque ripple suppression are given, and the new driving method is proposed. The MSWS driving is simple, easy to use, and greatly improves torque characteristics and the dynamic performance of DSM compared with square-wave driving. It is proposed for DSMs, however, it could be extended to other nonsinusoidal motors. This driving method is verified on a 12/8 DSM by simulation and experiment.

A stick-slip linear actuator with high speed and nano-resolution by resonance/non-resonance hybrid driving.

Abstract: To achieve high speed, nano-resolution, and large stroke, a resonance/non-resonance hybrid piezoelectric stick-slip actuator with a lever-type flexure hinge (LTFH-PSSA) is proposed in this work. The actuator can achieve high speed and large stroke in the resonance mode by the stick-slip working principle and achieve nano-resolution in the non-resonant mode by the direct drive working principle. The excitation electrical signals used in the two working modes are the sine waveform and half-sine waveform, respectively. Compared with the traditional sawtooth waveform, the excitation signal of the sine and half-sine waveforms have no sudden change of voltage, which are more conducive to reduce the impact and vibration of the system. Moreover, a series of static analysis and modal analysis of the stator are carried out by the finite element method. The experimental system is built to test the output characteristics of the LTFH-PSSA. In the resonance state by the stick-slip working principle, the impedance analysis and frequency characteristic test of the LTFH-PSSA are carried out, which states that the tested resonance frequency agrees well with the simulated ones. When the locking force, the voltage, and the frequency are 2 N, 100 Vp-p, and 1850 Hz, the speed of the LTFH-PSSA is up to 52.71 mm/s, and the backward motion is suppressed completely as well. In the non-resonance state, the resolution can reach 2.19 nm and 2.69 nm in the forward and backward motion, respectively. So far, the proposed actuator ranks first in speed and resolution among all reported LTFH-PSSAs.

Investigation of the effect of wavy honeycomb on the bending performance of the sandwich structure

Abstract: Sandwich structures are frequently used in structural areas where lightness and strength are essential. These structures are indispensable for sailing boats, and ground and air vehicles. The base purpose of this study is to investigate the effect of wave parameters on the sandwich structure. The data obtained from the bending tests of the model created using Ls-Dyna was compared with the experimental data of the literature. There is a 3.05% difference between the peak force in experimental and Ls-Dyna. The force-deformation plots are coherent, and the progressive images of the sandwich structure during bending are similar. In addition, using theoretical approaches, the highest force and the amount of collapse during bending were determined. There is a difference of 3.1% between the theoretical approach and Ls-Dyna values. Thus, the Ls-Dyna model was validated. The flat cell walls of the honeycomb were modeled as a sine wave. Four wave numbers and wave amplitudes were used. In this way, 16 different analysis files were created. The results show that the new sandwich structure’s specific peak force and specific energy absorption (SEA) increased by 7–110% compared to the ordinary flat walled sandwich structure. This research will assist in the design of new sandwich structures.

Resonances at Fundamental and Harmonic Frequencies for Selective Imaging of Sine‐Wave Illuminated Reversibly Photoactivatable Labels

Abstract: Abstract We introduce HIGHLIGHT as a simple and general strategy to selectively image a reversibly photoactivatable fluorescent label associated with a given kinetics. The label is submitted to sine‐wave illumination of large amplitude, which generates oscillations of its concentration and fluorescence at higher harmonic frequencies. For singularizing a label, HIGHLIGHT uses specific frequencies and mean light intensities associated with resonances of the amplitudes of concentration and fluorescence oscillations at harmonic frequencies. Several non‐redundant resonant observables are simultaneously retrieved from a single experiment with phase‐sensitive detection. HIGHLIGHT is used for selective imaging of four spectrally similar fluorescent proteins that had not been discriminated so far. Moreover, labels out of targeted locations can be discarded in an inhomogeneous spatial profile of illumination. HIGHLIGHT opens roads for simplified optical setups at reduced cost and easier maintenance.

A piecewise sine waveguide for terahertz traveling wave tube

Abstract: Abstract In this paper, a piecewise sine waveguide (PWSWG) is proposed as the slow-wave structure (SWS) to develop high-power terahertz (THz) traveling wave tubes (TWTs). The PWSWG is an improvement over the rectangular waveguide wherein its two E-planes simultaneously oscillate up and down along the longitudinal direction. The oscillation curve in the H-plane is a piecewise sine curve formed by inserting line segments into the peaks and troughs of the sine curve. The simulation analysis and experimental verification show that the PWSWG offers the advantages of large interaction impedance and excellent electromagnetic transmission performance. Furthermore, the calculation results of beam–wave interaction show that the TWT based on PWSWG SWS can generate a radiated power of 253.1 W at the typical frequency of 220 GHz, corresponding to a gain of 37.04 dB and an interaction efficiency of 6.92%. Compared with the conventional SWG TWTs, the PWSWG TWT has higher interaction efficiency and shorter saturation tube length. In conclusion, the PWSWG proposed in this paper can be considered a suitable SWS for high-power THz radiation sources.

Active Cancellation of Periodic CM EMI at the Input of a Motor Inverter by Injecting Synthesized and Synchronized Signals (S³-AEF)

Abstract: Active electromagnetic interferences (EMI) cancellation is a promising solution to reduce the size of passive filters. Power electronic systems may generate periodic disturbances if they are controlled by periodic signals in steady-state operation. Periodic disturbances can be represented by a set of sine waves, according to the Fourier theory, and can be suppressed by an appropriate set of cancelling sine waves injected into the system. Since bothersome effects, like delay times or complex transfer functions, can be compensated by individually selecting the appropriate amplitude and phase for each cancelling sine wave, high EMI reductions can be achieved in a wide frequency range. In this contribution, this cancellation method is applied to the common-mode EMI of a three-phase motor inverter in stationary operation with periodic control signals in the frequency range from 150 kHz to 30 MHz. Approximately 2.4 million harmonics are suppressed. The characteristics of the overall system are discussed and the challenges for the cancellation system are elaborated. A method for the synthesis of the cancellation signal is introduced. The design of the cancellation system is described, and its signal processing is presented. The outstanding performance is proven by reference measurements in a laboratory setup. Extensions for practical applications are discussed.

Exotical solitons for an intrinsic fractional circuit using the sine-cosine method

Abstract: This work focuses on seeking soliton solutions for an intrinsic fractional discrete nonlinear electrical transmission network obtained through the simplest sine-cosine method. The studied model is governed by a fractional nonlinear partial differential-difference equation in (2 + 1) spatio-temporal dimensions, and the method used to get exact solutions is simple, concise and well-known. We achieve for the model studied here that, the sought solutions specifically by means of the sine-cosine method are functions of all the capacitor's nonlinearities (quadratic and cubic) if and only if, we use the fourth-order spatial dispersion (FOSD)during the continuous media approximation. In contrast, in the absence of the FOSD term, the solutions only exist if, either the quadratic or the cubic nonlinearity is considered separately. In addition, the obtained solutions shapes are exotical, unexpected and novel. These findings (singular bright solitary waves, pulse, U-shaped and M-shaped waves trains) get many applications; for instance, codifying data in the allowed or forbidden band for the signal's transmission in the waveguides.

Design of Sine Filter for GTO-Based Auxiliary Converter for Electric Locomotive Using MATLAB Simulink

Abstract: This paper presents the converter topology for one-phase to three-phase auxiliary converter for three-phase electric locomotive. GTO-based auxiliary converter has no sine filter and due to this most of the auxiliary machines are being operated on non-sinusoidal power supply, which results in poor machine performance. Hence, we made efforts to design a circuit of sine filter by MATLAB Simulink technique which results in desired sinusoidal output waveform which increases the life of a machine and decreases the human efforts required per machine and maintenance cost of a machine. So, this is a solution to achieve the desired parameters and waveforms using sine filter for auxiliary machines in three-phase electric locomotive.

Sensorless Load Angle Control for Energy Optimal Sinusoidal Driven BLDC Motor Applications

Abstract: Choosing sine-wave instead of square-wave shaped currents to drive a brushless DC (BLDC) motor can increase the energy-efficiency up to 9.5%.But, unfortunately, for sine-wave setpoint current generation, the typical electronic or sensing low-resolution commutation feedback techniques become unavailable. For broad industrial employability, other sensing techniques such as computationally complex observers or signal injection methods requiring access to the switching states of the power electronics are not preferred. This raises the need to develop a computationally sufficient simple sensorless controller that optimizes the energy efficiency. Therefore, the authors propose a PID algorithm controlling the estimated load angle technique that enables sinusoidal current supply without the need for position feedback or user input. The aim is to implement a controller for dynamic speed-varying BLDC motor applications, which means that accurate speed trajectory tracking behavior and high robustness against load changes should be guaranteed. The application-dependent PID settings for setpoint and disturbance rejection control are estimated during an initialization speed trajectory based on only one stator winding current and voltage measurement. The proposed control algorithm is validated through experimental measurements on a BLDC motor with a nominal speed and power of 3000 r/min and 225 $\mathrm{W}$ , respectively.

Bipolar SHEPWM for Pure Sine Wave Single-Phase Inverter

Abstract: Modern power systems, like DC-AC inverters, use simple control strategies. However, they give rise to harmonic problems during the switching process. It impacts the total system performance.In this paper, Selective Harmonic Elimination SHEPWM was adopted to mitigate these undesirable harmonic distortions. It cancels odd harmonic at optimized switching angles. In this case, it aims to eliminate the first 100 low-order harmonics. The fsolve function was used to calculate the optimized 50 angles for the SHEPWM by solving the non-linear transcendental equations in MATLAB. The resulting SHEPWM is implemented in a low-cost high-performance PIC18F26K22 microcontroller. It controls a pure sine wave single-phase inverter in ISIS space. Finally, an LC low-pass filter is connected at the inverter output to ameliorate its response and obtain a better sinusoidal AC waveform with a lower THD.