High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

Quanming Luo,Binxin Zhu,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Quanming Luo,Shubo Zhi,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

An Active Clamp High Step-Up Boost Converter with a Coupled Inductor

Quanming Luo,Yang Zhang,Pengju Sun,Luowei Zhou 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1

An active clamp high step-up boost converter with a coupled inductor is proposed in this paper. In the proposed strategy, a coupled inductor is adopted to achieve a high voltage gain. The clamp circuit is included to achieve the zero-voltage-switching (ZVS) condition for both the main and clamp switches. A rectifier composed of a capacitor and a diode is added to reduce the voltage stress of the output rectifier diode. As a result, diodes with a low reverse-recovery time and forward voltage-drop can be utilized. Since the voltage stresses of the main and clamp switches are far below the output voltage, low-voltage-rated MOSFETs can be adopted to reduce conduction losses. Moreover, the reverse-recovery losses of the diodes are reduced due to the inherent leakage inductance of the coupled inductor. Therefore, high efficiency can be expected. Firstly, the derivation of the proposed converter is given and the operation analysis is described. Then, a steady-state performance analysis of the proposed converter is analyzed in detail. Finally, a 250 W prototype is built to verify the analysis. The measured maximum efficiency of the prototype is 95%.

An Active Clamp High Step-Up Boost Converter with a Coupled Inductor

Luo, Quanming,Zhang, Yang,Sun, Pengju,Zhou, Luowei The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1

An active clamp high step-up boost converter with a coupled inductor is proposed in this paper. In the proposed strategy, a coupled inductor is adopted to achieve a high voltage gain. The clamp circuit is included to achieve the zero-voltage-switching (ZVS) condition for both the main and clamp switches. A rectifier composed of a capacitor and a diode is added to reduce the voltage stress of the output rectifier diode. As a result, diodes with a low reverse-recovery time and forward voltage-drop can be utilized. Since the voltage stresses of the main and clamp switches are far below the output voltage, low-voltage-rated MOSFETs can be adopted to reduce conduction losses. Moreover, the reverse-recovery losses of the diodes are reduced due to the inherent leakage inductance of the coupled inductor. Therefore, high efficiency can be expected. Firstly, the derivation of the proposed converter is given and the operation analysis is described. Then, a steady-state performance analysis of the proposed converter is analyzed in detail. Finally, a 250 W prototype is built to verify the analysis. The measured maximum efficiency of the prototype is 95%.

High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

Luo, Quanming,Zhu, Binxin,Lu, Weiguo,Zhou, Luowei The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Luo, Quanming,Zhi, Shubo,Lu, Weiguo,Zhou, Luowei The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

Research on rural residential houses in North region of Henan Province -Taking Jiaozuo as an Example-

Chen KaiDi,Xie QuanMing,Kim JuneBong 국제온돌학회 2013 International Journal of Ondol Vol.6 No.1

By selecting rural residential houses of Jiaozuo region as the research object, paper analyzes local residential houses' origin, formation and development. Base on searching literature study, field research, and summarizing the previous analysis methods, firstly, describe the form of rural residential houses in Jiaozuo region; secondly, analyses the causes of architectural evolution; lastly, summarizes the evolution laws. Then combined with related domestic and abroad instance, paper is to propose reasonable advice and strategies for preservation and update the rural residential houses in Jiaozuo.

Simultaneous removal of sulphide and nickel by the compound of Chitosan Schiff Base from crude oil under microwave irradiation

Lei Wang,Quanming Peng,Shuzhen Li,Liucheng Du,Haijun Cai 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

A study has been carried out for simultaneous desulfurization and demetalization by electric desalting from crude oil based on the oxidation of alkyl thiophene and nickel compounds with the compound of Chitosan Schiff Base under the condition of microwave irradiation (SDDM). Besides, an investigation has been made about the influence of Chitosan Schiff Base compound dose, initial temperature, and microwave time on desulfurization and demetalization. By using the optimized conditions for SDDM, up to 56% of sulfur and 82% of nickel removal rates were achieved for model compounds in crude oil samples. With the same conditions but without microwave the removal efficiency was lower than 56%for sulfur model compound and than 82% for nickel porphyrin in crude oil samples. Additionally, in order to develop a fundamental understanding of the SDDM mechanism of sulfides, a molecular simulation of sulfur compounds was performed with both the Hartree–Fock (HF) and second-order Moller–Plesset (MP2) levels of theory for the calculation of reaction kinetic rate by using Gaussian 03 program package. In comparison with conventional desulfurization and demetalization technology, the proposed SDDM process can accomplish the simultaneous removal of sulfur and nickel compounds from crude oil under relatively mild conditions.

Analysis and Design of Function Decoupling High Voltage Gain DC/DC Converter

Yuqi Wei,Quanming Luo,Xingyu Lv,Pengju Sun,Xiong Du 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Traditional boost converters have difficulty realizing high efficiency and high voltage gain conversion due to 1) extremely large duty cycles, 2) high voltage and current stresses on devices, and 3) low conversion efficiency. Therefore, a function decoupling high voltage gain DC/DC converter composed of a DC transformer (DCX) and an auxiliary converter is proposed. The role of DCX is to realize fixed gain conversion with high efficiency, whereas the role of the auxiliary converter is to regulate the output voltage. In this study, different forms of combined high voltage gain converters are compared and analyzed, and a structure is selected for the function decoupling high voltage gain converter. Then, topologies and control strategies for the DCX and auxiliary converter are discussed. On the basis of the discussion, an optimal design method for circuit parameters is proposed, and design procedures for the DCX are described in detail. Finally, a 400 W experimental prototype based on the proposed optimal design method is built to verify the accuracy of the theoretical analysis. The measured maximum conversion efficiency at rated power is 95.56%.

Weibel instability and structures of magnetic island in anti-parallel collisionless magnetic reconnection

Lu, San,Lu, Quanming,Shao, Xi,Yoon, Peter H.,Wang, Shui American Institute of Physics 2011 Physics of plasmas Vol.18 No.7