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Topic

Harmonic

About: Harmonic is a research topic. Over the lifetime, 44833 publications have been published within this topic receiving 495922 citations. The topic is also known as: overtone & partial.


Papers
More filters
Journal ArticleDOI
TL;DR: Based on the current mode control and load current feed forward, two control methods to achieve low SHC in the front-end dc-dc converter and fast dynamic performance during load transient are proposed.
Abstract: Two-stage single-phase inverters have been widely used as they can achieve voltage matching and galvanic isolation between the input and output. Due to the pulsating output power of the downstream inverter, an ac current at twice the output frequency, which is called second harmonic current (SHC), arises in the input side of the downstream inverter. This SHC will penetrate to the front-end dc-dc converter, leading to reduced conversion efficiency. This paper first analyzes the propagation mechanism of the SHC and load transient response of two-stage single-phase inverters from the viewpoint of output impedance. Then, based on the current mode control and load current feed forward, two control methods to achieve low SHC in the front-end dc-dc converter and fast dynamic performance during load transient are proposed in this paper. Finally, a 2-kW two-stage single-phase inverter prototype has been constructed and tested, and the experimental results are provided to verify the effectiveness of the proposed control methods.

94 citations

Journal ArticleDOI
TL;DR: It is shown that contrast is superior to tissue when using low frequencies and imaging the third or fourth harmonic of the transmitted frequency.

94 citations

Journal ArticleDOI
TL;DR: In this article, the harmonic amplification problems in a plastics plant and the appropriate mitigation methods were investigated and two high-pass damped filters were recommended to replace the original single-tuned filters.
Abstract: This paper investigates the harmonic amplification problems in a plastics plant and the appropriate mitigation methods. Four single-tuned filters (LC filters) were installed to eliminate the harmonic currents from three 6-pulse rectifiers. However, after the capacitance reduction of some filter capacitors, the driving point impedance at the frequency of 8th order harmonic increased severely and the harmonic current of this order was amplified. There were many failures of the power filter capacitors. Field measurements and computer simulations are used to verify the disturbance problems. Finally, two high-pass damped filters are recommended to replace the original single-tuned filters. The amplification problems at some even-order harmonics can be avoided.

94 citations

Journal ArticleDOI
TL;DR: In this article, a theoretical model is presented describing harmonic heat flow in a two-layer system heated by a modulated Gaussian laser beam Amplitude and phase of the modulated temperature rise in the layers, as well as in the backing substrate and adjacent atmosphere, are calculated by solving the three-dimensional heat conduction equation with a source term including exponential absorption of the laser light in one or two layers.
Abstract: A theoretical model is presented describing harmonic heat flow in a two layer system heated by a modulated Gaussian laser beam Amplitude and phase of the modulated temperature rise in the layers, as well as in the backing substrate and adjacent atmosphere, are calculated by solving the three‐dimensional heat conduction equation with a source term including exponential absorption of the laser light in one or two layers Heat conduction is assumed to be isotropic throughout the system, however, a thermal contact resistance between the two layers can be taken into account Results are presented for single and double layer systems of gold and various dielectric thin film materials on glass substrates Amplitude and phase of the harmonic temperature variation are calculated either as a function of position in the sample system or at the surface as a function of the laser beam modulation frequency It is found that both amplitude and phase of the calculated temperature rise exhibit typical thin film features i

94 citations

01 Jan 1990
TL;DR: In this paper, a photoelectric plethysmograph was used to determine how the pulse shape varied with age using 54 subjects in three age groups, 10-29, 30-59, and 60-89 years.
Abstract: A photoelectric plethysmograph is described that per- forms a frequency analysis of the peripheral volume pulse wave using a portable computer. It was used to determine how the pulse shape varied with age using 54 subjects in three age groups, 10-29, 30-59, and 60-89 years. The youngest group had a larger power in the second harmonic, (normalized to the fundamental), with p < 0.05 than the older two groups. The decrease of power in the harmonics of the pe- ripheral pulse wave with age may be a useful noninvasive measure of aging and vascular disease.

94 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,223
20222,724
20211,878
20202,330
20192,612
20182,495