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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
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Proceedings ArticleDOI
15 Oct 2007
TL;DR: A useful analytical expression for the torque ripple is developed that highlights the stator-rotor harmonic interactions and an analytical design procedure for IPM rotors with multiple flux barriers is proposed that applies the mutual harmonics exclusion principle in combination with stator windings that use even numbers of slots per pole pair.
Abstract: The interior permanent magnet (IPM) synchronous machine is vulnerable to developing significant amounts of current-induced ripple torque depending on the details of the machine design. Building on the contributions of earlier researchers, this paper approaches the problem of torque ripple reduction in IPM machines by applying the principle of mutual harmonics exclusion. First, this paper develops a useful analytical expression for the torque ripple that highlights the stator-rotor harmonic interactions. Next, an analytical design procedure for IPM rotors with multiple flux barriers is proposed that applies the mutual harmonics exclusion principle in combination with stator windings that use odd numbers of slots per pole pair. Finally, the technique is applied to two example IPM machines to investigate the effectiveness of this approach using finite element analysis. Promising results predict that a low peak-to-peak torque ripple can be achieved using relatively small numbers of stator slots and rotor flux barriers for the full range of current control angles, including deep flux weakening.

92 citations

Journal ArticleDOI
TL;DR: In this article, a wideband open-loop active harmonic load-pull measurement approach is presented, which is based on wideband data-acquisition and wideband signal-injection of the incident and device generated power waves at the frequencies of interest.
Abstract: A new wideband open-loop active harmonic load-pull measurement approach is presented. The proposed method is based on wideband data-acquisition and wideband signal-injection of the incident and device generated power waves at the frequencies of interest. The system provides full, user defined, in-band control of the source and load reflection coefficients presented to the device-under-test at baseband, fundamental and harmonic frequencies. The system capability to completely eliminate electrical delay allows to mimic realistic matching networks using their measured or simulated frequency response. This feature enables active devices to be evaluated for their actual in-circuit behavior, even on wafer. Moreover the proposed setup provides the unique feature of handling realistic wideband communication signals like multicarrier wideband code division multiple access (W-CDMA), making the setup perfectly suited for studying device performance in terms of efficiency, linearity and memory effects.

92 citations

Journal ArticleDOI
TL;DR: In this article, a method to evaluate harmonic contributions at the point of common coupling is presented, which is based on the harmonic current vector method where reference impedances are introduced, and long-term measurements are proposed for determination of harmonic contributions.
Abstract: A method to evaluate harmonic contributions at the point of common coupling is presented in this paper. The proposed approach is based on the harmonic current vector method where reference impedances are introduced. Resistance defined at fundamental frequency with measurements is used as the customer-side reference impedance. The presented method allows calculation of harmonic contributions without knowing the actual customer impedances. It also enables better evaluation of the customer and utility harmonic contributions in resonance conditions. The method is verified through a simulation study and with extensive field measurements. Long-term measurements are proposed for determination of harmonic contributions.

92 citations

Journal ArticleDOI
TL;DR: In this paper, the second-harmonic signal peaks at incidence angles corresponding to enhanced transmission of the fundamental beam of 800 nm wavelength except at small incidence angles where the local symmetry minimizes the effective second-order nonlinear susceptibility of the apertures.
Abstract: We demonstrate the generation of second-harmonic radiation in transmission through periodic and disordered arrays of sub-wavelength metallic apertures. For circular apertures in a square lattice, the second-harmonic signal peaks at incidence angles corresponding to enhanced transmission of the fundamental beam of 800 nm wavelength except at small incidence angles where the local symmetry minimizes the effective second-order nonlinear susceptibility of the apertures. Even though the linear transmission of the fundamental beam can be more than five times greater through the periodic array as compared to a disordered array, the strength of the second harmonic from the disordered array is greater at large incidence angles. By breaking the local symmetry through the use of apertures of non-centrosymmetric shape, the second-harmonic output occurs at fundamental transmission resonances at small incidence angles.

92 citations

Journal ArticleDOI
TL;DR: This paper introduces an advanced current control strategy for grid-connected operations of distributed generation (DG), which supports the DG to transfer a sinusoidal current into the utility grid despite the distorted grid voltage and nonlinear local load conditions.
Abstract: This paper introduces an advanced current control strategy for grid-connected operations of distributed generation (DG), which supports the DG to transfer a sinusoidal current into the utility grid despite the distorted grid voltage and nonlinear local load conditions. The proposed current controller is designed in the synchronous reference frame and composed of a proportional-integral (PI) controller and a repetitive controller (RC). An RC serves as a bank of resonant controllers, which can compensate a large number of harmonic components with a simple delay function. Hence, the control strategy can be greatly simplified. In addition, the proposed control method does not require the local load current measurement or harmonic analysis of the grid voltage. Therefore, the proposed control method can be easily adopted into the traditional DG control system without installation of extra hardware. Despite the reduced number of sensors, the grid current quality is significantly improved compared with the traditional methods with the PI controller. The operation principle of the proposed control method is analyzed in detail, and its effectiveness is validated through simulated and experimental results.

92 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