Topic
Sine wave
About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.
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TL;DR: In this paper, a flat-roofed sine waveguide slow-wave structure (FRSWG-SWS) was proposed for a W-band sheet electron beam (SEB) traveling-wave tube (TWT) based on flat-Roofed Sine Waveguide (SWG) structure.
Abstract: A W-band sheet electron beam (SEB) traveling-wave tube (TWT) based on flat-roofed sine waveguide slow-wave structure (FRSWG-SWS) is proposed. The sine wave of the metal grating is replaced by a flat-roofed sine wave around the electron beam tunnel. The slow-wave characteristics including the dispersion properties and interaction impedance have been investigated by using the eigenmode solver in the 3-D electromagnetic simulation software Ansoft HFSS. Through calculations, the FRSWG SWS possesses the larger average interaction impedance than the conventional sine waveguide (SWG) SWS in the frequency range of 86-110 GHz. The beam-wave interaction was studied and particle-in-cell simulation results show that the SEB TWT can produce output power over 120 W within the bandwidth ranging from 90 to 100 GHz, and the maximum output power is 226 W at typical frequency 94 GHz, corresponding electron efficiency of 5.89%.
20 citations
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TL;DR: In this article, a 1-kW interactive inverter for direct photovoltaic energy feedback to the mains has been realized, where a modulated buck converter converts the dc current to a rectified 50-Hz sine wave current, and the following self-commutated half-bridge generates a 50Hz SINW current, which is fed into one phase of the public power grid.
Abstract: A new regulated utility interactive inverter for direct photovoltaic energy feedback to the mains has been realized. A modulated buck converter converts the photovoltaic dc current to a rectified 50-Hz sine wave current, and the following self-commutated half-bridge generates a 50-Hz sine wave current, which is fed into one phase of the public power grid. This nonclassical inverter needs only three power transistor switches and isolates the grid and the photovoltaic array using a commercial 50-Hz transformer. It acts as a current source, and due to pulsewidth modulation its output is a sine wave current with very low total harmonic distortion of one percent. The overall efficiency of the 1-kW prototype is at least 88 percent between 250 and 1000 W, and the projected efficiency is over 90 percent for 1-20 kW. Furthermore, a circuit which tracks the maximum power available from the photovoltaic generator has been developed. This circuit regulates the input power to its maximum by detecting the phase angle between the voltage and power ripples at the inverter input.
20 citations
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11 Mar 1976
TL;DR: A welding wire feed method and apparatus as discussed by the authors involves feeding a welding wire in a conduit cable to a workpiece, while maintaining it normally in one plane in the form of a sine curve in the conduit cable.
Abstract: A welding wire feed method and apparatus involves feeding a welding wire in a conduit cable to a workpiece, while maintaining it normally in one plane in the form of a sine curve in the conduit cable.
20 citations
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27 May 2009
TL;DR: In this paper, a method for direct torque control of a step wave back electromotive force brushless direct current motor is presented. But the method is not suitable for a sine wave permanent magnetic synchronous motor.
Abstract: The invention discloses a method for direct torque control of a stepped wave back electromotive force brushless direct current motor and belongs to a method for controlling a permanent magnetic synchronous motor. A torque adjusting signal KT, a stator magnetic linkage adjusting signal Kpsi and a stator magnetic linkage phase angle theta of the stepped wave back electromotive force brushless direct current motor are input into a switch state table to obtain a three-phase switch state of a three-phase full-bridge inverter. The three-phase switch state runs through the three-phase full-bridge inverter, produces certain basic vector to directly control actual stator magnetic linkage psi and actual torque T of the stepped wave back electromotive force brushless direct current motor. The method combines an idle load stator magnetic linkage track rule and three-phase synchronous conduction (no intermittent phase) of a sine wave permanent magnetic synchronous motor and the advantages of simple structure and high power density of a 120 degree square wave brushless direct current motor, improves the utilization rate of a permanent magnet (which is 1.3 times that of the120 degree square wave brushless direct current motor) and simplifies a motor body and a control system.
20 citations
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TL;DR: Both short term noise and long term instability of the IFOG are reduced by this novel method of quadrature demodulation with synchronous difference for suppressing noise in interferometric fiber-optic gyroscopes (IFOGs).
Abstract: We propose a novel method of quadrature demodulation with synchronous difference for suppressing noise in interferometric fiber-optic gyroscopes (IFOGs). For an IFOG with sine wave phase modulation, an in-phase result and a quadrature result are obtained simultaneously by coherent detection. Eigenfrequency modulation is used and a phase shift of 45° is set between the modulation signal and the reference signal, so that two results have the same expectation of amplitude but with opposite signs. A synchronous difference procedure is carried out for output, in which signals are added up and common noise between two results is eliminated. Theoretical analysis and experimental results show that both short term noise and long term instability of the IFOG are reduced by this method. In experimental comparison with the traditional demodulation method on the same IFOG with a 1982 m fiber coil, this method reduces the bias drift from 0.040°/h to 0.004°/h.
20 citations