Search results for "Transform"
showing 10 items of 3975 documents
An improved Flyback converter
2009
This paper presents a modified Flyback converter able to operate with higher efficiency and smaller size, overcoming most of the conventional flyback converter drawbacks, and also keeping its low cost and simplicity. In particular, the proposed converter allows the mosfet off voltage to be reduced and clamped to the input, thus recovering the transformer leakage energy. As a consequence, the duty cycle can be extended to unity, thus reducing the voltage stress across the output rectifier, and lowering both the magnetizing inductance and the transformer bias current values. In addition, due to the auxiliary mosfet, the magnetizing current can become negative, eliminating the discontinuous co…
Small-Signal Modeling of a Controlled Transformer Parallel Regulator as a Multiple Output Converter High Efficient Post-Regulator
2004
This paper presents a post-regulator based on the use of a controlled transformer, which adds or subtracts an additional voltage to the output filter of a converter in order to regulate its output voltage. So, their actuation is complementary to that of more known post-regulators, such as the magnetic amplifier (magamp) and synchronous switch post-regulator (SSPR), because the regulation is achieved by controlling the voltage across the filter inductor instead of its charge time. Besides, the post-regulator processes the power in parallel to the one flowing from input to output and only handles a percentage of it. The post-regulation by controlled transformer is suitable of being employed i…
A high-efficiency regulation technique for a zero-voltage zero-current power switching converter
1998
This paper describes the application of a new regulation technique to a resonant converter that features zero-voltage (ZV) and zero-current (ZC) switching and works at constant frequency and duty cycle. The regulator utilizes the concept of regulating only a percentage of the total power in a bidirectional manner, thus allowing the converter to be optimized for both mass and efficiency. The proposed regulation technique has a wide range of applicability to almost all types of power converters or inverters that utilize a transformer to produce an isolated output. By using the concept of addition or subtraction of AC voltages, a fully regulated output voltage is achieved. The resultant effect…
A demagnetization circuit for forward converters
2009
This paper presents a demagnetization circuit able to operate the forward converter with an higher efficiency and with a wider input range. In particular, by the means of few added components, the magnetizing energy and the leakage one are continuously recovered, and the transformer reset and the primary mosfet OFF voltage clamp to the input, both under steady state and transient operations, are provided. The reduced voltage stress allows the converter to operate with a duty extended to unity over the typical 70% limit of the Active Clamp topology, with smaller output inductance, better converter dynamics and wider input range. Furthermore, thanks to this technique, by employing a duty appr…
ATR-FTIR spectroscopy for the routine quality control of exosome isolations
2021
Abstract Exosomes are nanosized vesicles containing specific cargos of DNA, RNA, proteins, metabolites, and intracellular and membrane lipids. Exosome isolation needs to be optimized carefully depending on the type of biofluid and tissue and the retrieved exosomes need to be characterized. The main objective of this study was to determine the feasibility of a multimodal analysis of Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and UPLC–QqTOF-MSMS for the development of a routine quality control tool of isolated exosomes and the rapid characterization of their lipid profiles and total protein content. Using human milk as model example, exosomes were isolat…
CROSS-POWER SPECTRAL DENSITY AND CROSS-CORRELATION REPRESENTATION BY USING FRACTIONAL SPECTRAL MOMENTS
2012
Filter equation by fractional calculus
2014
Aim of this paper is to represent a causal filter equation for any kind of linear system in the general form L=f(t), where f(t) is the forcing function, x(t) is the output and L is a summation of fractional operators. The exact form of the operator L is obtained by using Mellin transform in complex plane.