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19 results on '"Han, Yehua"'

13. Detailed Oscillation Analysis and Parameter Selection Principle for Boost PFC Converter With RC Snubber Operated in DCM

Author

Kai Yao, Hairui Xu, Ke Yun, Qiang Li, and Han Yehua

Subjects
Physics, Total harmonic distortion, Oscillation, 020208 electrical & electronic engineering, 02 engineering and technology, Power factor, Inductor, Inductance, Parasitic capacitance, Control theory, Parasitic oscillation, 0202 electrical engineering, electronic engineering, information engineering, Snubber, Electrical and Electronic Engineering
Abstract

The parasitic parameters of a boost power factor correction converter lead to input current distortion when the converter operates in discontinuous conduction mode, and using an RC snubber is a simple and effective way to suppress the parasitic oscillation. The effect of the RC snubber on the parasitic oscillation is analyzed in detail, and three different forms of the characteristic roots are obtained according to different RC values. The optimal RC values and their relationship between the inductance and parasitic capacitance are figured out, which can achieve a lowest total harmonic distortion. A 1-kW prototype has been built and tested at low power and the experimental waveforms and data are presented to validate the theoretical analysis.

Published
2019

15. A Series Diode Method of Suppressing Parasitic Oscillation for Boost PFC Converter Operated in Discontinuous Conduction Mode

Author

Hairui Xu, Kai Yao, Junchao Song, Han Yehua, and Qiang Li

Subjects
Series (mathematics), Oscillation, 020208 electrical & electronic engineering, 05 social sciences, 02 engineering and technology, Power factor, Inductor, Control theory, Parasitic oscillation, Distortion, 0502 economics and business, 0202 electrical engineering, electronic engineering, information engineering, 050211 marketing, Electrical and Electronic Engineering, Current (fluid), Mathematics, Diode
Abstract

When a boost power factor correction converter operates in a discontinuous conduction mode, the nonzero characteristic of the average current in oscillation period and the initial value of the inductor current in a switching cycle are the main cause of the influence of the parasitic parameters on input current distortion. The effect of parasitic parameters oscillation is analyzed in detail, and a new method of series diode is proposed, which can effectively decrease the input current distortion and improve the power factor. Selection principles of series diode are given. Experimental results verify the correctness and the feasibility of the theoretical analysis.

Published
2018

19. [Some advances and prospects in fingerprintings of traditional Chinese medicines].

Author

Han Y, Huo F, Yang Y, Liao Y, and Liu H

Subjects
Chromatography trends, Drugs, Chinese Herbal isolation & purification, Drugs, Chinese Herbal standards, Quality Control, Chromatography methods, Drugs, Chinese Herbal analysis, Drugs, Chinese Herbal chemistry, Medicine, Chinese Traditional standards
Abstract

The quality control standards are the key points in the modernization of traditional Chinese medicines (TCM), and in recent years, the fingerprinting techniques play an increasingly important role, including fingerprintings based on gas chromatography, liquid chromatography, capillary electrophoresis, spectroscopic methods, and so on. Some advances in this area in the past few years are reviewed and some prospects are discussed in this article.

Published
2008

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