Browsing by Author "Liu, HF"

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A flexible and cost-effective family for AC/DC converters with input-current-shaper and fast output-voltage-regulation
(2004)
Chang, LK
;
Liu, HF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a flexible and cost-effective design for AC/DC Converter with input current shaper and fast output voltage regulation in wide range input application. These single-stage AC/DC converters are based on a boost type input-current-shaper (ICS). An additional winding in main transformer replaces most part of a bulk inductor in a boost type ICS, so the weight and size of magnetic material are significantly reduced. The total harmonic distortion (THD) of a line current complies with IEC61000-3-2. A magnetic feedback method is employed in the new topologies. Therefore, the voltage across bulk capacitor can be hold under 450v by tuning transformer windings ratio even though the converter operates in wide range input voltage (90vsimilar to265v/ac). A fast output voltage regulation is achieved by employing simple voltage mode control or conventional peak-current mode control.
A flexible and low cost design for flyback AC/DC converter with harmonic current correction
(2003)
Chang, LK
;
Liu, HF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A new simple flyback AC/DC converter with harmonic current correction and fast output voltage regulation is presented. In the proposed AC/DC converter, an extra winding is wounded in transformer and yields two major merits: The bulk inductor used in the conventional boost-based PFC cell is omitted in the proposed converter and consequently almost 1/2 volume and weight in magnetic material can be saved. The voltage across bulk capacitor can be hold under 450v by tuning transformer windings ratio. even though the converter operates in wide range of input voltage (90vsimilar to265v/ac). This new converter complies with IEC 61000-3-2 under the load range of 200w and it has fast output voltage regulation.
A novel and low cost design for forward AC/DC converter with harmonic current correction
(2004)
Chang, LK
;
Liu, HF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a new simple Forward AC/DC converter with harmonic current correction and fast output voltage regulation. In the proposed AC/DC converter, an extra winding wounded in transformer provides two major merits: The function of bulk inductor has been replaced by this extra back-feeding transformer winding in the proposed converter and significant volume and weight In magnetic material can be saved. The voltage across bulk capacitor can be hold under 450v by tuning transformer windings ratio even though the converter operates In wide range Input voltage (90v similar to 265v/ac). This new converter complies with IEC 61000-3-2 under the load range of 200w and It has fast output voltage regulation.
A novel forward AC/DC converter with input current shaping and fast output voltage regulation via reset winding
(2005-02-01)
Chang, LK
;
Liu, HF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a novel simple forward ac/dc converter with harmonic current correction and fast output voltage regulation. In the proposed ac/dc converter, a transformer incorporating reset winding provides two main advantages. First, the bulk inductor used in the conventional boost-based power-factor-correction cell is omitted in the proposed converter, allowing significant volume and weight of magnetic material to be saved. Second, the voltage across the bulk capacitor can be held under 450 V by adjusting the transformer winding ratio, despite the converter operating in a wide range of input voltages (90similar to265 V/ac). This new converter complies with IEC 61000-3-2 under a load range of 200 W and has fast output voltage regulation.
Flexible and low cost design for a flyback AC/DC converter with harmonic current correction
(2005-01-01)
Liu, HF
;
Chang, LK
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study presents a new simple flyback ac/dc converter with harmonic current correction and fast output voltage regulation. In the proposed ac/dc converter, an extra winding wound in the transformer provides two key advantages. The size of the bulk inductor used in the conventional boost-based power factor correction cell can be significantly reduced in the proposed converter., The voltage across bulk capacitor can be held under 450 V by tuning the transformer winding ratio even though the converter operates in a wide range of input voltages (90 Vsimilar to265 V/ac). This new converter complies with IEC 61000-3-2 under the load range of 200 W, and can achieve fast output voltage regulation.
Implementation of ZVT soft switching technique in a single-phase PFC rectifier for server power supply
(2000)
Liu, HF
;
Liu, YH
;
Tzou, YY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This of paper presents the design and implementation of a zero-voltage-transition power factor correction (PFC) converter which can achieve high power factor, low harmonic distortion, and high efficiency. Zero-voltage-transition soft-switching technique has been applied to reduce the switching losses of the auxiliary switching circuit for a single-phase sc-de converter with unit power factor. Its kW, 200 kH5 soft-switching single-phase PFC converter has operation principle and design equations have been given. A 2 been constructed. An efficiency of 94% at rated output has been measured. Experimental results show the developed design procedure for the ZVT soft-switching PFC converter can achieve unit power factor, high efficiency, and low EMI.