Browsing by Author "Chang, LK"

Now showing 1 - 9 of 9

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AC/DC converter, an extra winding wounded in transformer provides two major merits: The function of bulk inductor has been replaced by this extra back-feeding transformer winding in the proposed converter and significant volume and weight In magnetic material can be saved.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.
An exponential-folds design of a charge pump styled DC/DC converter
(2004)
Chang, LK
;
Hu, CH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A charge pump styled DC/DC converter utilizing the exponential-folds structure and the pumping gain increase (PGI) circuit with high voltage transfer efficiency is proposed in this paper. A PGI circuit used in the linear DC/DC converter is proposed to solve the threshold voltage problem and limitation of the diode-con figured output stage so that the boosted output voltage increases more linearly versus the pumping stage number. With the exponential-folds structure, fewer voltage pump stages are needed to obtain the higher output voltage and further improve the voltage pumping gain. Especially, this design still has good efficiency with low input supply voltage such as one battery cell.
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.
High efficiency MOS charge pumps based on exponential-gain structure with pumping gain increase circuits
(2006-05-01)
Chang, LK
;
Hu, CH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Novel MOS charge pumps utilizing an exponential-gain structure and pumping gain increase (PGI) circuits with high voltage transfer efficiency to generate boosted output voltages are described. By using the PGI circuits, the threshold voltage problem of the MOSFET used as a switch is solved, and the limitation of the diode-configured output stage is removed. Thus, the boosted output voltage increases linearly as compared to the pumping stage number. An exponential-gain structure is also presented as a further application of the PGI circuit. By using this structure, fewer voltage pump stages are needed to obtain the required output voltage. For 1.5-V supply voltage operation, a four-time series (1.5 V-to-6 V) is demonstrated using the new techniques. Simulation and experimental results have shown that this design has good efficiency with a low-input supply voltage such as a one battery cell.
Model reduction techniques for speeding up the thermal simulation of printed circuit boards
(2000-11-01)
Chang, LK
;
Shui, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper initiates a measuring method to reduce the traditional three-dimensional thermal circuit models into the two-dimensional compact ones. The new thermal models are represented by the equivalent circuits which can be simulated in the SPICE. Furthermore, the ambient temperature and the power of the components are also decoupled to equivalent voltage and current sources, respectively. Therefore, when the ambient temperature or the power of the component changes, the compact thermal models can still work without doing any regeneration work. The proposed technique can greatly reduce the simulation time of heat transfer of printed circuit boards. Furthermore, the reduced models can be connected to any place on the model of the printed circuit board. The proposed technique provides a systematic synthetic way to build up models of printed circuit boards.
The design of automatic-lock-automatic-retrieve single-chip IPM for converter systems
(2001)
Chang, LK
;
Tsai, MY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper describes a single-chip intelligent power module (IPM) manufactured by utilizing a modified high voltage BCD process that integrates power devices, LIGBTs, and protection circuits on the SOI substrate. The smart integrated circuits provide automatic-lock-automatic-retrieve sensing and protection functions To give strong and fast protection ability against faults of over-on-state-voltage, over-current, and over-temperature, those are specially designed for power converter usage. When the gate voltage of LIGBT is high and the faulty event is sensed, the protection circuit pulls down the gate voltage to low and toggles LIGBT to off state immediately. However, each time the gate voltage returns to high, LIGBT is retrieved to the normal operating condition automatically. Therefore, the proposed IPM can operate superior in the converters with pulse-width-modulation (PWM) applications.