A hybrid active filter for damping of harmonic resonance in industrial power systems

This paper proposes a hybrid active filter for damping of harmonic resonance in industrial power systems. The hybrid filter consists of a small-rated active filter and a 5th tuned passive filter. The active filter is characterized by detecting the 5th harmonic current flowing into the passive filter. It is controlled in such a way as to behave as a negative or positive resistor by adjusting a feedback gain from a negative to positive value, and vice versa. The negative resistor presented by the active filter cancels a positive resistor inherent in the passive filter, so that the hybrid filter acts as an ideal passive filter with infinite quality factor. This significantly improves damping the harmonic resonance, compared with the passive filter used alone. Moreover, the active filter acts as a positive resistor to prevent an excessive harmonic current from flowing into the passive filter. Experimental results obtained from a 20 kW laboratory model verify the viability and effectiveness of the hybrid active filter proposed in this paper </p

キョコウ ノ ナマエ ニ ツイテ

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コトバ ニ ミチタ カンキョウ セイタイガクテキ ゲンゴ リロン ノ タメ ノ 5ツ ノ カセツ

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Composition and Antioxidant Activity of Rice Fermented with Saccharifying Organisms from Asian Countries

In recent years, more effective use of rice has become important because of an annual increase in surplus rice. We fermented rice in pure cultures of eight organisms (Aspergillus oryzae, Monaseus pilosus, Absidia corymbifera, Mucor circinelloides, Mucor racemosus, Rhizopus oligosporus, Rhizopus oryzae, and Saccharomycopsis fibuligera), which were isolated from molded rice and soybean products in Asian countries, and evaluated the composition and antioxidant activity of the products. Rice fermented with the two Rhizopus species had a high methanol extract yield, implying good fermentation properties. High saccharification and increased levels of total amino acids and total polyphenols were also found in Rhizopus-fermented rice samples. Ethyl acetate extracts of rice fermented with Ab. corymbifera and Mu. circinelloides had enhanced antioxidant activity compared to unfermented rice, and some fractions obtained from the extracts by high performance liquid chromatography exhibited high antioxidant activity. Based on these results, Ab. corymbifera, Mu. circinelloides, R. oligosporus, and R. oryzae are promising starter organisms for the development of new fermented rice products.ArticleFOOD SCIENCE AND TECHNOLOGY RESEARCH. 19(5):893-899 (2013)journal articl