A novel control scheme for simultaneous elimination of imbalance, disturbance and voltage harmonic in power systems

In recent years, the increasing application of nonlinear and unbalanced electronic equipment and large single phase loads have made voltage imbalance a serious problem in power distribution systems. A novel approach has been proposed to eliminate voltage imbalance and disturbances. The main strategy of this scheme is based on series active filter. By improving control circuit toward existing schemes and proposing a new strategy to control the voltage amplitude, simultaneous elimination of voltage imbalance, faults, voltage harmonics and also compensation of voltage drop in transmission lines become possible. Eventually, the voltage on the load side is a perfectly balanced three phase voltage with specific proper amplitude. The proposed scheme has been simulated in a test network and the results show high capability of this scheme for the complete elimination of imbalance without phase shift.

Harmonic Filter Design to Mitigate Two Resonant Points in a Distribution Network

This paper investigates the usage of passive harmonic filters to mitigate harmonic distortions when two resonant points are present in a system caused by shunt capacitors used for power factor correction and bus voltage regulation. Six scenarios were investigated using DIgSILENT 14 power factor）＇ software. The investigations are with and without power factor correction and capacitors used to increase bus voltage. Passive harmonic filters are designed to reduce harmonic distortions at the PCC （point of common coupling） to fall within the IEEE 519 harmonic voltage and current limits caused by parallel resonance. The results of the case studies are analysed to evaluate the effectiveness of the filter design.

Intense ke V IAP generation by orthogonally polarized multicycle midinfrared two-color laser fields

We theoretically investigate the attosecond pulse generation in an orthogonal multicycle midinfrared two-color laser field. It is demonstrated that multiple continuum-like humps, which consist of about twenty orders of harmonics and an intensity of about one order higher than the adjacent normal harmonics, are generated when longer wavelength driving fields are used. By filtering these humps, intense isolated attosecond pulses（IAPs） are directly generated without any phase compensation. Our proposal provides a simple technique to generate intense IAPs with various central photon energies covering the multi-ke V spectral regime by using multicycle midinfrared driving pulses with high pump energy in the experiment.

Planar Magnetic Integrated Harmonic Filter with Reduced EMI Noise

Through the analysis of the circuit structure and electromagnetic interference(EMI)conduction path,the structure of the traditional harmonic filter is optimized so that it has the ability to suppress EMI.Using the structure of planar magnetic integration not only ensures the basic harmonic suppression ability of the harmonic filter,but also improves the EMI suppression effect.With a single-phase voltage source 500-W SiC inverter as the platform,the feasibility and effectiveness of the design scheme are experimentally verified.The results indicated that the planar magnetic integrated harmonic EMI filter satisfies the design requirements.Additionally,the proposed planar magnetic integration scheme can significantly reduce the volume and weight of the filter and increase the power density of the entire system.

An Improved Algorithm of Harmonic Mean Filter

Rafael C. Gnzalez has mentioned an algorithm on adaptive local noise elimination filter in the book named Digital Image Processing. This paper points out the algorithm＇s deficiency and presents an improved harmonic mean filter algorithm which makes mean square error emse cutting quarter but SNR, SNPm and PSNR increasing a tenth more than original algorithm. This filter algorithm is verified to be effective by simulation experiment.

Technological Research on Navigation System Interfered by Harmonic Wave

Electromagnet interference troubles are more and more and complex with each pass day along with improvement of large system electronization. This article will analyze the interference problems caused by harmonic waves in large system. The generation,characteristic and perniciousness of harmonic waves will be qualitatively analyzed for summarizing practical experience to provide mentality and method for settling the large system electromagnet interference trouble. This article raises the approach and method of harmonic suppression from the root of harmonic generation during ultrashort wave transmission and through actual test and analyzing verification. The effectivity and correctness of the methods adopted are certified by theoretical analysis and experimental verification.