Thesis for the Degree of Ph. Modified Double-Dual-Boost Structure with Common Ground and Low-Side Gate Driving for DC-DC Converter and PFC Rectifier School of Architectural, Civil, Environmental, and Energy Engineering, Major in Energy Engineering The Graduate School Nguyen Chan Viet June 2022 The Graduate School Kyungpook National University Modified Double-Dual-Boost Structure with Common Ground and Nguyen Chan Viet 2022 Low-Side Gate Driving for DC-DC Converter and PFC Rectifier Modified Double-Dual-Boost Structure with Common Ground and Low-Side Gate Driving for DC-DC Converter and PFC Rectifier Nguyen Chan Viet School of Architectural, Civil, Environmental, and Energy Engineering, Major in Energy Engineering The Graduate School Supervised by Professor Honnyong Cha Approved as a qualified thesis of Nguyen Chan Viet for the degree of Ph. by the Evaluation Committee June 2022 Chairman Prof. Bon-Gwan Gu ○ 인 Prof.
Honnyong Cha ○ 인 Prof. Byungcho Choi ○ 인 Prof. Byeongcheol Han ○ 인 Prof. Jae-Jung Jung ○ 인 The Graduate School Council Kyungpook National University Modified Double-Dual-Boost Structure with Common Ground and Low-Side Gate Driving for DC-DC Converter and PFC Rectifier Viet Chan Nguyen School of Architectural, Civil, Environmental, and Energy Engineering, Major in Energy Engineering The Graduate School, Kyungpook National University Daegu, Korea (Supervised by Professor Honnyong Cha) (Abstract) This thesis proposes a modified double-dual-boost (MDDB) high- conversion-ratio DC-DC converter.
The proposed converter is derived from the existing double-dual-boost (DDB) converter by a simple yet effective circuit modification. The new structure inherits all the advantages of the existing DDB converter as high voltage gain, low voltage stress on switching devices, and power-sharing function. Moreover, due to the circuit modification, the input and output can share a common ground, enabling the use of low-side gate drivers for all switching devices. When compared with the existing DDB converter, the proposed converter requires only one more capacitor and one more inductor.
However, the seemingly two inductors can be integrated into a single inductor. Thus, the overall magnetic volume is the same as the conventional DDB converter. i Unlike the DDB converter, the proposed structure can be used for power-factor-correction (PFC) applications. The boost or interleaved boost converter in the conventional PFC structure can be replaced by the proposed converter to reduce the cost and improve the efficiency.
Owing to the intrinsic power-sharing between the phases, the number of current sensors is reduced. It results in reducing the hardware cost and the complexity of the controller. Moreover, the MDDB converter has a higher voltage gain but lower switching devices voltage stress than the conventional two-phase interleaved boost converter (2P-IBC); therefore, the proposed PFC can achieve higher efficiency, especially at low-line voltage. The above advantages make the proposed structure quite suitable for universal-line (85–265 VRMS) PFC applications.
The first Chapter of this thesis is devoted to the introduction of DC-DC boost converters and the existing DDB converter. The MDDB converter is introduced and is carefully analyzed in the second Chapter. After that, the PFC based on the MDDB structure is presented in the third Chapter, and the conclusions are given in the final Chapter. ii Acknowledgments I would like to express my most sincere gratitude and appreciation to my supervisor, Prof.
Honnyong Cha, for his constant support, motivation, encouragement, and guidance throughout my studies at Kyungpook National University. His amazing knowledge, advice, and expertise have been a valuable source for my Ph. I would like to thank Prof. Honnyong Cha for allowing me to grow as a research scientist.
I would like to thank my Ph. dissertation committee members Prof. Bon-Gwan Gu, Prof. Byungcho Choi, Prof.
Byeongcheol Han, Prof. Jae-Jung Jung, and Prof. Honnyong Cha for serving as my Ph. dissertation committee members.
I also want to thank them for their valuable comments and suggestions. Further, I would like to thank my colleagues at Power Electronics and Magnetics Design Laboratory (PEMD), Dr. Kisu Kim, Dr. Fazal Akbar, Dr.
Tien-The Nguyen, Mr. Bang Le-Huy Nguyen, Mr. Dai-Van Bui, Mr. Nabeel Naseem, Mr.
Emmanuel Seun Oluwasogo, Mr. Ubaid Ahmad, Mr. Faramarz Faraji Mr. Jeonghun Kim, Mr.
Seunghoon Lee, Mr. Daheon Hong, Mr. Jaeseong Lim, Mr. Yeongjin Kim, Mr.
Dongheon Lee, Mr. Juyoung Park for letting my Ph. studies and research enjoyable and memorable. With my heartfelt respect, I would like to thank my parents, my sister, and my girl for their everlasting love and support.
Without them, my Ph. would have never been possible. iii List of Content 1 Chapter I.1 Categorization of Step-Up DC-DC Converters.1 Isolated and non-isolated DC-DC converters .2 Unidirectional and bidirectional DC-DC converters.3 Voltage-fed and current-fed DC-DC Converters .4 Hard-switched and soft-switched DC-DC converters .5 The requirements of a DC-DC converter for PFC applications .2 Voltage-Boosting Techniques .2 Switched inductor and voltage lift .4 Voltage multiplier cells.3 Double-Dual-Boost Converter .1 Interleaved double-dual boost converter. Modified Double-Dual-Boost Structure 20 2.1 The Motivation of Circuit Modifications.3 Operation Principle of the Proposed DDB Converter .4 Characteristics of the MDDB Converter .2 Inductor current balancing.3 Comparison of the 2P-IBC, the existing/proposed DDB converters .5 Input current ripple .6 Semiconductor losses analysis .5 Simulation and Experimental Results .6 Influences of Leakage Inductance on the MDDB Converter .7 Influences of turns-ratio on the proposed DDB converter.
Power Factor Correction Based on the MDDB Structure 67 3.1 Overview of Power Factor Correction .3 Output capacitor Co.4 Switching devices S1, S2, D1, and D2 .3 Voltage feed-forward compensator .4 Start-up sequence .4 Simulation and Experimental Result .1 The simulation results.1 Summary and Contribution. 104 1 References 105 vi List of figures Chapter I Fig.1 Categorization of step-up DC-DC converters.3 Two voltage-doublers are cascade connected .2 The operation stages of the voltage-doubler based on the switched capacitor technique. a) Stage 1: C is charged. b) Stage 2: C discharges in series with Vin .4 The operation of boost converter with switched inductor cell.5 The operation of: a) Basic switched inductor cell.
b) Self-lift switched inductor cell. c) Double self-lift switched inductor cell.6 Active switched inductor converter based on switched inductor .7 Classic voltage multiplier cells. a) Switched/diode capacitor VMC. b) VMC with capacitor, diode, and inductor.
c) VMC with resonant inductor.8 Boost converter based on Voltage multiplier circuits .9 Double-dual-boost converter.10 Operation of the DDB converter (a) Mode 0.11 Key waveforms of the DDB converter when D < 0.12 Key waveforms of the DDB converter when D > 0. 18 Chapter II Fig.1 Double-dual-boost converter.2 Derivation of the proposed converter. (a) Step 1: move (L2) to the top and add L3 and Co. (b) Step 2: connect C2 to the top.
(c) Step 3: move D2 to the top.3 Modified double-dual-boost converter.4 Re-drawing of the modified double-dual-boost converter.5 Operation for the proposed DDB converter (a) Mode 0.6 Key waveforms of the MDDB converter when D < 0.7 Key waveforms of the MDDB converter when D > 0.8 The voltage gain of MDDB converter and 2P-IBC.9 Two-leakage inductance model of coupled inductor.10 The proposed DDB converter with equivalent inductors .11 The input current of the proposed DDB converter when D < 0.12 The input current of the proposed DDB converter when D > 0.13 The ratio of input and inductor current ripple vs. duty cycle of the MDDB converter.14 Input current ripple comparison of three converter at the same voltage gain (Vo/Vin).15 The commutation of MOSFET .16 The key losses of the proposed converter at Vin = 170 V, Vo = 400 V, Po = 2 kW.17 Efficiency of the proposed converter at Vin = 170 V, Vo = 400 V, Po = 2 kW .18 Simulation waveforms when D = 0.4, Vin = 170 V, Vo = 400 V, Po = 2 kW 51 Fig.19 Simulation waveforms when D = 0.7, Vin = 70 V, Vo = 400 V, Po = 2 kW 52 Fig.20 Prototype photo of the MDDB converter .21 Efficiency of the MDDB converter .22 Experimental waveforms of the MDDB converter at D = 0.4, Vin = 170 V, Vo = 400 V, Po = 2 kW.23 Experimental waveforms of the MDDB converter at D = 0.7, Vin = 70 V, Vo = 400 V, Po = 2 kW.24 Winding configuration of coupled inductors. (a) Tightly coupled inductor. (b) Loosely coupled inductor.
(c) Photo of coupled inductors.25 Switching device voltages of the MDDB converter at D = 0. (a) With tightly coupled inductor. (b) With loosely coupled inductor.26 The experience curves of voltage gain vs.27 Two-leakage inductance model of coupled inductor .28 Equivalent inductance vs. turns-ratio at: (a) k = 0.29 The proposed DDB converter with equivalent inductors .30 Simulation results of the proposed DDB converter with k = 0.8 and the turns-ratio: (a) n = 0.
66 Chapter III Fig.1 a) PFC based on 2P-IBC.2 Conventional boost PFC during: a) positive half cycle. b) Negative half cycle.3 The operation of Bridgeless PFC during: a) Positive half-line cycle. b) Negative half-line cycle.4 Bridgeless PFC boost rectifier with two additional diodes .5 The proposed PFC based on MDDB converter .6 The L1 inductor current of MDDB PFC .7 The control diagram of the proposed PFC .8 The calculation method of average rectifier voltage .9 Start-up sequence of the proposed PFC .10 Simulation waveforms of the proposed PFC when Vin = 120 V, Po = 1600 W .11 Simulation waveforms of the proposed PFC when Vin = 220 V, Po = 1600 W .12 Simulation waveforms of step input voltage at full-load.13 Simulation waveforms of step load from 800 W to 1600 W.6-kW prototype of the proposed PFC.15 Experimental waveforms of the proposed PFC when Vin = 120 V, Po = 1600 W .16 Experimental waveforms of the proposed PFC when Vin = 220 V, Po = 1600 W .17 The startup waveforms of the proposed PFC when.18 Efficiency of the proposed PFC and 2P-IBC.19 Input current total harmonic distortion graph of the proposed PFC .20 Power factor of the proposed PFC system. 100 x List of Tables TABLE 1.1 Categorization of Step-Up DC-DC Converters Fig.1 Categorization of step-up DC-DC converters.
The DC-DC converter topologies can be classified based on their operational characteristics. As shown in Fig.1, the step-up DC-DC converters can be essentially classified as isolated or non-isolated, unidirectional or bidirectional, current-fed or voltage-fed, and hard-switched or soft-switched. The details of each type are described below.1 Isolated and non-isolated DC-DC converters The conventional boost converter is a basic method for stepping up a dc voltage, which comprises only three components (a switch, a diode, and an inductor). A boost 1 converter is a simple, low-cost, and efficient non-isolated step-up converter that is suitable for many dc applications [1], [2].
Regarding the presence of galvanic isolation, DC-DC converters can be classified into isolated or non-isolated. The galvanic isolation on the converter can be obtained by using transformers. In addition, the transformer also can decide the converter voltage gain through the winding turns-ratio. However, the leakage inductance of the transformer windings causes high voltage spikes on the switching devices and, consequently, high switching losses and low switch utilization [3], [4].
Therefore, the non-isolated converters without magnetic coupling can be a simple and adequate solution for applications that do not require high voltage gain or high efficiency. There are also non-isolated DC-DC converters that use a built-in transformer or coupled inductor. These solutions are suitable for applications where high voltage gain with high efficiency and reliability are demanded [5], [6].2 Unidirectional and bidirectional DC-DC converters In almost DC-DC applications, the power only flows in one direction (from input to output) [7], [8], [9], [10]. This feature is demanded in applications where the load should only supply by the input source.
The unidirectional converters usually are cheaper and more compact compared to the bidirectional ones due to requiring fewer components and an uncomplicated control strategy. Besides, in applications that have 2 energy storage systems, the DC-DC converters must be able to transfer energy bi- directionally to charge and discharge the energy storage components.3 Voltage-fed and current-fed DC-DC Converters Regarding the input filter, DC-DC converters can be divided into voltage-fed and current-fed.
