Browsing by Author "Chang, Lon-Kou"

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A single stage single switch parallel AC/DC converter based on two output boost-flyback converter
(2006)
Li, Heng-Yi
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Chang, Lon-Kou
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A single-stage-single-switch (S4) parallel ac-to-dc converter based on single-switch-two-output (SSTO) boost-flyback converter is presented. This converter remarkably improves the power processing performance. The converter contains two semi-stages. One is the boost-flyback semi-stage that has excellent self-PFC property when operating in DCM even though the boost output is close to the peak value of the line voltage. Moreover, it allows part input power transferred to load directly through the flyback path so the power conversion efficiency is improved. The other one is the forward semi-stage that provides another parallel power flow path and improves the regulation speed. Furthermore, the bulk capacitor voltage is low due to only partial power is processed through it. Hence, the proposed converter is suitable for universal input usage.
An Isolated Full-Bridge DC-DC Converter With 1-MHz Bidirectional Communication Channel
(2011-09-01)
Yang, Ru-Shiuan
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Chang, Lon-Kou
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Chen, Hung-Chi
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電機工程學系
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Department of Electrical and Computer Engineering
This paper presents a novel isolated full-bridge dc/dc converter with bidirectional communication capability. The transformer in the proposed converter is utilized as an isolation interface for transferring both energy and data. Power delivery and forward data transfer are conducted simultaneously by modifying the full-bridge switching phase. Backward data transfer is realized by manipulating the amplitude of the resonant signal through modulating the impedance of the resonant tank at the secondary side of the transformer. Finally, the operation principle of the proposed converter was verified on a 900-mW prototype operating at 1 MHz from a 12-V dc input.
An Isolated Full-Bridge DC/DC Converter with Bidirectional Communication Capability
(2008)
Chang, Lon-Kou
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Yang, Ru-Shiuan
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交大名義發表
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National Chiao Tung University
This work presents a novel isolated full-bridge DC/DC converter with bidirectional communication capability. The transformer in the proposed converter is utilized as an isolation interface for transferring energy and data. Power delivery and forward data transfer are conducted simultaneously by modifying the full-bridge switching phase. Backward data transfer is realized by manipulating the amplitude of the resonant signal through modulating the impedance of the resonant tank at the secondary side of the transformer. Finally, the operation principle of the proposed converter was verified on a 280mW prototype operating at 400kHz from a 12V DC input.
Analysis and Design of a Single-Stage Parallel AC-to-DC Converter
(2009-12-01)
Li, Heng-Yi
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Chen, Hung-Chi
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Chang, Lon-Kou
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, a single-stage (S(2)) parallel ac-to-dc converter based on single-switch two-output boost-flyback converter is presented. The converter contains two semistages. One is the boost flyback semistage, which transfers partial input power transferred to load directly through one power flow path and has excellent self-power factor correction property when operating in discontinuous conduction mode even though the boost output is close to the peak value of the line voltage. The other one is the flyback dc-to-dc (dc/dc) semistage that provides the output regulation on another parallel power flow path. With this design, the power conversion efficiency is improved and the current stress of control switch is reduced. Furthermore, the calculation process of power distribution and bulk capacitor voltage, design equations, and design procedure for key parameters are also presented. By following the procedure, an 80 W prototype converter has been built and tested. The experimental results show that the measured line harmonic current at the worst condition complies with the IEC61000-3-2 class D limits, the maximum bulk capacitor voltage is about 415.4 V, and the maximum efficiency is about 85.8%. Hence, the proposed S(2) converter is suitable for universal input usage.
Analysis and modeling of on-chip charge pump designs based on pumping gain increase circuits with a resistive load
(2008-07-01)
Hu, Chih-Huei
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Chang, Lon-Kou
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電控工程研究所
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Institute of Electrical and Control Engineering
A complete equivalent model and analysis of high-efficiency charge-pump gain-increase (PGI) circuits with resistive loads are proposed. Based on this simple analytical model, the characteristics of PGI circuits can be approximately predicted and several handy equations, which are useful for pencil-and-paper design, can also be found for planning the desired circuit to achieve good enough performance with an acceptable accuracy tolerance in the steady state. In addition, an optimized design method for PGI circuits with resistive loads is developed in terms of the total number of gain stages in the design and the ratio between pump capacitors. For 1.5 V supply voltage operation, reliability and accuracy are demonstrated by comparisons between SPICE simulations of the PGI circuit and the results from the equivalent model. The model also has been validated by means of measurements taken from a test chip and typically shows relative open-loop output voltage errors lower than 8%. Finally, although the derivation of the model was based on a PGI circuit, it is shown that the design strategy can also be applied to other charge pump designs that have no voltage drop between the inner stages and the output stage.
Simple bridge-type AC/DC converters with natural input-current-shaper
(2006)
Liu, Hsing-Fu
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Wu, Chih-Yu
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Sun, Chin
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Chang, Lon-Kou
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電控工程研究所
This paper presents a new design for bridge-type AC/DC converters with natural input current shaper. They have a fast output voltage regulation in full range input (85V similar to 265V/AC). An additional winding in main transformer can naturally modify a line current. Further, the additional winding reduces an input inductance, so the weight and size of magnetic material are significantly reduced. The total harmonic distortion (THD) of the line current complies with IEC61000-3-2 class D. Furthermore, the proposed converters use current sensorless control and they can employ a conventional voltage-fed controller to simply the control circuit.
Single-Stage Soft-Switching AC-DC Converter With Input-Current Shaping for Universal Line Applications
(2009-02-01)
Liu, Yen-Ming
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Chang, Lon-Kou
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, a novel single-stage soft-switching ac-dc converter for universal line applications is presented. Unlike the conventional single-stage designs, the proposed input-current shaping scheme is intentionally arranged to be charged in the duty-off time. With this design, the switch current stress in the duty-on time is significantly reduced. Meanwhile, this design produces ac modulation effect on the charging time of the boost inductor so that the input i-v curve drawn by the proposed converter has nearly linear relationship. Moreover, an active-clamp flyback-forward topology is used as the downstream de-de cell to alleviate voltage stress across the bulk capacitor. By deactivating the flyback subconverter and keeping the forward subconverter supplying the output power at light-load condition, the bulk-capacitor voltage can be alleviated effectively and guaranteed below 450 V in wide ranges of output load and line input (90-265 V(rms)). Experimental results, obtained from a prototype circuit with 20-V/100-W output, have verified that three achievements can be obtained simultaneously, including the compliance with the line-current harmonic regulations, the reliable alleviation of the bulk-capacitor voltage stress, and the substantially promoted conversion efficiency.
電漿火炬電力供應系統之開發
(2005)
張隆國
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Chang, Lon-Kou
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國立交通大學電機與控制工程研究所
電力系統模組化的優點在於: (1)提供較可靠的電源供應，具有備用模組者可靠度更高。(2) 模組元件的標準化，容易設計且減少製造成本及時間。(3) 可以線上更換模組。(4) 對整個系統而言，可以帶來較高的功率和功率密度。(5) 減少組件的應力，各模組零件均勻老化因而壽命延長。為了解決傳統電漿火炬電源系統的缺點，開發高效率、低成本、高可靠度之電漿火炬電力系統模組，我們將以小功率電源轉換器為基礎實現高功率之電力模組，並驗證其擴充的可行性，同時符合IEEE以及IEC對輸入電流諧波(Current Harmonic)污染之規範。此外，為了符合低成本、高功率的需求，我們採用全橋式單級交/直流轉換器做為電源系統的基本模組；此外，欲降低轉換器的切換損失，提升轉換器的效率以降低工作溫度及延長元件使用壽命，我們在轉換器的設計上，加上了柔性切換(Soft Switching)。在設計一新型轉換器架構時，我們將針對轉換器的能量傳遞與電路工作效能觀點做分析，目的在達到單級式交/直流轉換器的最佳化設計。電漿火炬的設計和操作方式有許多種類，所需之電源供應器的電壓和電流需求也因此有很大的分佈，故在設計時應考量極大功率負載需求時，該如何擴充轉換器模組。為此，針對輸入/輸出高電壓及輸出高電流型式之電漿火炬負載，其電源模組的設計採用單級交/直流轉換器的串聯組合，使用電壓共享技術以達成負載所要求的輸入/輸出高電壓規格；而輸出高電流的需求則以模組間並聯連接的方式來實現。在實作方面，每個交/直流轉換器模組設計成定電流輸出，且輸入與輸出端具有與其他模組串聯的電壓共享功能，模組最高電壓輸出為50V、電流最大為10A。