New means of generating a low-frequency sine-wave signal with a low harmonic distortion coefficient and the problems of providing metrological backup

2011 ◽  
Vol 54 (7) ◽  
pp. 813-818
Author(s):  
A. V. Andriyanov ◽  
A. P. Balaev ◽  
M. V. Pugin ◽  
A. I. Smekalov
Keyword(s):  
Harmonic Distortion ◽  
Low Frequency ◽  
Sine Wave ◽  
Wave Signal ◽  
Distortion Coefficient ◽  
Metrological Backup

Design of High Precision Power Supply for Low-Frequency Vibration Cutting

2004 ◽  
Vol 471-472 ◽  
pp. 494-497
Author(s):  
X.G. Jiang ◽  
D.Y. Zhang
Keyword(s):  
Power Amplifier ◽  
High Precision ◽  
Frequency Band ◽  
Power Supply ◽  
High Stability ◽  
Low Frequency ◽  
Sine Wave ◽  
Vibration Cutting ◽  
Low Frequency Vibration ◽  
Small Band

The frequency of piezoelectric transducer requires high stability and can also be continuously changed. The voltage requires smooth and stable sine wave. To the two problems, a high precision power supply for vibration cutting is designed. It divides the whole frequency band into several small bands. By means of CPLD, the sine wave is digitally fitted individually at each small band. So the sine wave can be always suitable at a wide frequency band. At the power output, OCL power amplifier is adopted. The output sine voltage becomes smooth and stable by adding voltage negative feedback to the power amplifier. The experiment results show its feasibility.

Design of Grid Connected Parallel Inverters with Interleaved Phase Shift by Using CAN Bus

2012 ◽  
Vol 591-593 ◽  
pp. 1579-1584
Author(s):  
Jyh Wei Chen ◽  
Huan Fu Lin
Keyword(s):  
Phase Shift ◽  
Harmonic Distortion ◽  
Sine Wave ◽  
Control Area ◽  
Total Output ◽  
Switching Frequency ◽  
Area Network ◽  
Output Current ◽  
Control Area Network ◽  
Master Module

A grid-connected parallel inverter with interleaved phase shift is proposed in this paper. The synchronous are generated by the master module to achieve interleaving phase shift PWM for the parallel inverters connected to grid-tied system that make the inverter to output current to the power line and share the load. TI TMS320F2812 DSP is used for system feedback control with voltage and current by using A/D converters to generate the output current close to sine wave. The expected output current values are determined by the master module and transmitted via CAN (Control area network) between inverter modules. The grid-tied system uses zero-voltage-detection circuit to synchronize the inverter currents with grid voltage. For each switching period, PWM voltage of two inverters are interleaved to reduce the total output current ripple so that the switching frequency can be reduced and the power system EMI problem can be alleviated as well. The experiment results are provided to verify the performance of the proposed system to reduce output current harmonic distortion.

scholarly journals Taste the Bass: Low Frequencies Increase the Perception of Body and Aromatic Intensity in Red Wine

2019 ◽  
Vol 32 (4-5) ◽  
pp. 429-454 ◽  
Author(s):  
Jo Burzynska ◽  
Qian Janice Wang ◽  
Charles Spence ◽  
Susan Elaine Putnam Bastian
Keyword(s):  
New Zealand ◽  
Cultural Production ◽  
Exploratory Study ◽  
Red Wine ◽  
Low Frequency ◽  
Sine Wave ◽  
Pinot Noir ◽  
Practical Application ◽  
Low Frequencies ◽  
Frequency Sound

Abstract Associations between heaviness and bass/low-pitched sounds reverberate throughout music, philosophy, literature, and language. Given that recent research into the field of cross-modal correspondences has revealed a number of robust relationships between sound and flavour, this exploratory study was designed to investigate the effects of lower frequency sound (10 Hz to 200 Hz) on the perception of the mouthfeel character of palate weight/body. This is supported by an overview of relevant cross-modal studies and cultural production. Wines were the tastants — a New Zealand Pinot Noir and a Spanish Garnacha — which were tasted in silence and with a 100 Hz (bass) and a higher 1000 Hz sine wave tone. Aromatic intensity was included as an additional character given suggestions that pitch may influence the perception of aromas, which might presumably affect the perception of wine body. Intensity of acidity and liking were also evaluated. The results revealed that the Pinot Noir wine was rated as significantly fuller-bodied when tasted with a bass frequency than in silence or with a higher frequency sound. The low frequency stimulus also resulted in the Garnacha wine being rated as significantly more aromatically intense than when tasted in the presence of the higher frequency auditory stimulus. Acidity was rated considerably higher with the higher frequency in both wines by those with high wine familiarity and the Pinot Noir significantly better liked than the Garnacha. Possible reasons as to why the tones used in this study affected perception of the two wines differently are discussed. Practical application of the findings are also proposed.

Optimal ventilation waveforms for estimating low-frequency respiratory impedance

1993 ◽  
Vol 75 (1) ◽  
pp. 478-488 ◽  
Author(s):  
K. R. Lutchen ◽  
K. Yang ◽  
D. W. Kaczka ◽  
B. Suki
Keyword(s):  
Broad Band ◽  
Viscoelastic Model ◽  
Harmonic Distortion ◽  
Low Frequency ◽  
Amplitude Dependence ◽  
Asthmatic Subject ◽  
Healthy Humans ◽  
Before And After ◽  
Airway Opening ◽  
Nonlinear Viscoelastic Model

We present a broad-band optimal ventilator waveform (OVW), the concept of which was to create a computer-driven ventilator waveform containing increased energy at specific frequencies (f). Values of f were chosen such that nonlinear harmonic distortion and intermodulation were minimized. The phases at each f were then optimized such that the resulting flow waveform delivered sufficient volume to maintain gas exchange while minimizing peak-to-peak airway opening pressure. Simulations with a linear anatomically consistent branching airway model and a nonlinear viscoelastic model showed that respiratory resistance (Rrs) and elastance (Ers) estimates at 0.1–2 Hz from the OVW are far superior to those from a standard step ventilator waveform (SVW) during healthy and obstructed conditions and that the OVW reduces the influences of harmonic interactions. Using a servo-controlled oscillator, we applied individual sine waves, an OVW containing energy at 0.15625–2.4 Hz, and an SVW to healthy humans and one symptomatic asthmatic subject before and after bronchodilation. The OVW was markedly superior to the SVW and always provided smooth estimates of Rrs and Ers. Before bronchodilation in the asthmatic subject Rrs was highly elevated and Ers was markedly increased with f; after bronchodilation the level of Rrs and the f dependence of Ers decreased. Although based on results from only one asthmatic subject, these data suggest a dominant influence of airway constriction and lung inhomogeneities during asthmatic bronchoconstriction that is alleviated by bronchodilators. These and other results indicate that the OVW approach has high potential for simultaneously probing f and amplitude dependence in the mechanical properties of clinical subjects during physiological breathing conditions and perhaps during dynamic bronchoconstriction.

Design of Digital Single-Phase Full-Bridge Invert Controller Based on TMS320F28027

2013 ◽  
Vol 448-453 ◽  
pp. 2137-2142
Author(s):  
Xiao Jian Ye ◽  
Zhen Gang Duan ◽  
Zhuo Shen ◽  
Xiao Qin Lian ◽  
Xiao Li Zhang
Keyword(s):  
Direct Current ◽  
Traditional Method ◽  
Single Phase ◽  
Sine Wave ◽  
New Method ◽  
Digital Controller ◽  
Duty Ratio ◽  
Current Signal ◽  
Wave Signal ◽  
Stable Performance

This paper elaborates a method to realize the single phase full bridge inverter digital controller based on DSP TMS320F28027 and gives the design scheme of both its hardware and its software. In accordance with SPWM duty ratio parameter calculated with DSP algorithm, utilizing the EPWM module on DSP, it finally attains the inverting control from direct current signal to sine wave signal. Compared with traditional method, this new method improves the output waveform effectively and shows stable performance.

scholarly journals Analisis Pengaruh Nilai Resistansi untuk Pentanahan Kawat Netral Terhadap THD Arus di Fakultas Teknik Universitas Udayana – Sudirman

2018 ◽  
Vol 5 (2) ◽  
pp. 167
Author(s):  
I G.N Nanda Ramdipa Amerta ◽  
I Wayan Rinas ◽  
I G.N Janardana
Keyword(s):  
System Modeling ◽  
Harmonic Distortion ◽  
Load Condition ◽  
Sine Wave ◽  
Harmonic Load ◽  
Electrical System ◽  
Nonlinear Loads ◽  
The Earth ◽  
Simulation Results ◽  
Resistance Value

Harmonics is a periodic sine wave distortion, due to the operation of nonlinear loads. Har-monics causes current to flow in the neutral wire even though in a balanced load condition, in addition to harmonic load imbalance problems will increase the current flowing in the neutral wire, making it dangerous for the electrical system. This research was using electrical system modeling simulation in MATLAB application by changing the earth resistance value to see the effect of earth resistance value to Total Harmonic Current Distortion (THDi), it is necessary to analyze the effect of resistance value for THDi neutral wire grounding. This study uses the Fast Fourier Transform (FFT) method. THDi simulation results when the conditions of the resistance value is 9 ?, THDi percentage in phase R is 6.30%, Phase S is 2.86%, Phase T is 2.50%. When the earth resistance value is 5 ?, the percentage of THDi decreases with the value in phase R is 6.09%, Fasa S is 2.61%, Fasa T is 2.48%. When the earth resistance value is 2 ?, the THDi percentage in the R phase is 5.85%, Fasa S is 2.09%, Fasa T is 2.22%. Based on the simulation results it is known that the smaller the earth resistance value, the smaller the harmonic distortion in the electrical system.

scholarly journals A New Modular Multilevel Inverter Based on Step-Up Switched-Capacitor Modules

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 524 ◽  
Author(s):  
Aryorad Khodaparast ◽  
Erfan Azimi ◽  
Ali Azimi ◽  
M. Ebrahim Adabi ◽  
Jafar Adabi ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
High Efficiency ◽  
Harmonic Distortion ◽  
Low Frequency ◽  
Multilevel Inverter ◽  
Voltage Source ◽  
Switched Capacitor ◽  
Level Control ◽  
Dc Voltage ◽  
Bipolar Voltage

A new structure of switched capacitor multilevel inverter (SCMLI) capable of voltage boosting and with self-balancing ability is introduced in this article. This advantage is the result of a step by step rise of capacitor voltages in each module, supplied by just one DC voltage source. The proposed topology generates a sinusoidal output waveform with a magnitude several times greater than the input one. Higher output staircase AC voltage is obtained by applying a nearest level control (NLC) modulation technique. The most significant features of this configuration can be mentioned as: fewer semiconductor devices, remarkably low total harmonic distortion (THD), desirable operating under high /low frequency, high efficiency, inherent bipolar voltage production, easy circuit expansion, ease of control and size reduction of the circuit thanks to utilizing neither bulky transformer nor inductor. Moreover, the proposed SCMLI is comprehensively surveyed through theoretical investigation and a comparison of its effectiveness to recent topologies. Eventually, the operating principle of a 25-level prototype of the suggested SCMLI is validated by simulation in the MATLAB SIMULINK environment and experimental results.

The Design and Implementation of High Precision Three-Phase Sine-Wave Signal Generator

2014 ◽  
Vol 543-547 ◽  
pp. 838-841
Author(s):  
Shou Qiang Kang ◽  
Shan Shan Li ◽  
Shi Zheng ◽  
Di Wu
Keyword(s):  
High Precision ◽  
Design Method ◽  
Synthesis Method ◽  
Sine Wave ◽  
Signal Generator ◽  
Lookup Table ◽  
Direct Digital Frequency Synthesis ◽  
Wave Signal ◽  
Design And Implementation ◽  
Three Phase

A design and implementation method of high precision three-phase sine-wave signal generator is proposed based on MCU and FPGA. For the traditional design method, direct analog synthesis method and phase locked loop (PLL) technology are used to design the signal generator. So the function, the precision and other aspects are inadequate. Aiming to the problem, a signal generator is designed based on direct digital frequency synthesis (DDS) technology. The MCU is used to control the peripheral devices and the frequency and phase control word can be obtained. The DDS module is achieved by EP4CE6E22C8 and the waveform lookup table addresses are outputted. The digital three-phase sine-wave data can be read from the lookup table. Through the three-way D/A converter and the amplifier circuit, the digital signal is converted to analog signal and the three-phase sinusoidal wave is outputted. The precision can be improved by increasing the sampling points, phase accumulator bits and D/A bits, and then, high precision three-phase sine-signal can be obtained and the adjustable frequency precision is 0.001.

Influence of low-frequency parameter changes on nonlinear vibro-acoustic wave modulations used for crack detection

2017 ◽  
Vol 17 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Bin Liu ◽  
Zhiwei Luo ◽  
Tie Gang
Keyword(s):  
Crack Detection ◽  
Crack Opening ◽  
Low Frequency ◽  
Intensity Variation ◽  
Sine Wave ◽  
Dynamic Strain ◽  
Low Frequency Vibration ◽  
Test Parameters ◽  
Increased Sensitivity ◽  
Acoustic Modulation

The use of vibro-acoustic modulation is an effective nonlinear and nondestructive approach to the detection and monitoring of cracks in fatigued, defective, and fractured materials. However, the vibro-acoustic modulation results strongly depend on choice of the testing parameters. To implement this technique for additional applications, the effect of variation in the test parameters must be well understood. This study investigates the influence of variation in the amplitude and frequency of pumping (low-frequency vibration) signals on the modulation. We apply two kinds of probing excitations, sine-wave and swept-signal excitations, and we measure the modulation intensity variation with changes in the relevant parameters to observe their influence on the modulations. Dynamic strain measurement of the crack area is utilized to analyze the relation between the degree of crack opening/closing and the modulation on the crack interface. The results indicate that the probing amplitude has little effect on the modulation, and furthermore, the sweep-signal excitation technique can be used to select the proper probing frequency. The results also indicate that there is a critical pumping strain value ( εc) for the crack samples. When the pumping strain reaches this critical value, the modulation reaches a maximum. However, the opening/closing area cannot increase any more even if the pumping amplitude further increases, and thus, the modulation does not change. The extent of the crack opening/closing also varies with the pumping frequency. Our results suggest that increased sensitivity to crack detection can be achieved with the use of the resonance frequency as the pumping frequency in vibro-acoustic modulation tests.

Sign in / Sign up

Export Citation Format

Share Document