The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the elec...The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the electrical properties,anisotropic preferred etching by means of optical microscopy,Fourier transform infrared spectroscopy and transmission electron microscopy.It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration.Furtherly,we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode.It is shown that the oxygen precipitations present in an "S" curve with increasing initial oxygen concentration after high temperature diffusion.The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF),which are mainly dislocations,and a small amount of rod stacking faults.The density of B-OSF increases with the increasing initial oxygen concentration.The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.展开更多
A junction barrier Schottky （JBS） rectifier with an improved P-well on 4H-SiC is proposed to improve the VF-IR trade-off and the breakdown voltage. The reverse current density of the proposed JBS rectifier at 300 K ...A junction barrier Schottky （JBS） rectifier with an improved P-well on 4H-SiC is proposed to improve the VF-IR trade-off and the breakdown voltage. The reverse current density of the proposed JBS rectifier at 300 K and 800 V is about 3.3 × 10-s times that of the common JBS rectifier at no expense of the forward voltage drop. This is because the depletion layer thickness in the P-well region at the same reverse voltage is larger than in the P＋ grid, resulting in a lower spreading current and tunneling current. As a result, the breakdown voltage of the proposed JBS rectifier is over 1.6 kV, that is about 0.8 times more than that of the common JBS rectifier due to the uniform electric field. Although the series resistance of the proposed JBS rectifier is a little larger than that of the common JBS rectifier, the figure of merit （FOM） of the proposed JBS rectifier is about 2.9 times that of the common JBS rectifier. Based on simulating the values of susceptibility of the two JBS rectifiers to electrostatic discharge （ESD） in the human body model （HBM） circuits, the failure energy of the proposed JBS rectifier increases 17% compared with that of the common JBS rectifier.展开更多
In nuclear fusion power supply systems, the thyristors often need to be connected in parallel for sustaining large current. However, research on the reverse recovery transient of parallel thyristors has not been repor...In nuclear fusion power supply systems, the thyristors often need to be connected in parallel for sustaining large current. However, research on the reverse recovery transient of parallel thyristors has not been reported yet. When several thyristors are connected in parallel,they cannot turn-off at the same moment, and thus the turn-off model based on a single thyristor is no longer suitable. In this paper, an analysis is presented for the reverse recovery transient of parallel thyristors. Parallel thyristors can be assumed as one virtual thyristor so that the reverse recovery current can be modeled by an exponential function. Through equivalent transformation of the rectifier circuit, the commutating over-voltage can be calculated based on Kirchhoff’s equation. The reverse recovery current and commutation over-voltage waveforms are measured on an experiment platform for a high power rectifier supply. From the measurement results, it is concluded that the modeling method is acceptable.展开更多
与传统高压感应电能传输(inductive power transfer,IPT)系统不同,高压输入-低压输出大功率IPT系统面临高降压比实现与二次侧导通损耗过大的核心挑战。为此,提出一种基于串联电容全桥逆变与同步反向耦合倍流整流的双通道IPT拓扑。该拓...与传统高压感应电能传输(inductive power transfer,IPT)系统不同,高压输入-低压输出大功率IPT系统面临高降压比实现与二次侧导通损耗过大的核心挑战。为此,提出一种基于串联电容全桥逆变与同步反向耦合倍流整流的双通道IPT拓扑。该拓扑在实现1/8电压转换比的同时,可将二次侧各线圈电流降至传统全桥整流方案的1/4,显著降低松耦合变压器的设计难度及二次侧线圈导通损耗。在阐述所提拓扑工作原理的基础上,详细开展IPT系统的参数设计与实现方案研究。为验证理论分析的正确性与方案有效性,搭建原理样机并进行实验测试。结果表明,样机实现28 V恒压输出与零相位角(zero phase angle,ZPA)运行,峰值效率达95.3%、满载效率达95%,充分证明了所提拓扑及设计方案的可行性、正确性与先进性。展开更多
单端初级电感变换器(SEPIC)是升-降压型变换器,具有输入电流脉动小、同极性输出和输入电压范围宽的优势,适用于诸如燃料电池、光伏发电等电压变化范围大的场合。简单介绍了SEPIC的工作原理,提出了应用同步整流和耦合电感技术的SEPIC数...单端初级电感变换器(SEPIC)是升-降压型变换器,具有输入电流脉动小、同极性输出和输入电压范围宽的优势,适用于诸如燃料电池、光伏发电等电压变化范围大的场合。简单介绍了SEPIC的工作原理,提出了应用同步整流和耦合电感技术的SEPIC数字电源,减少了整流器件的损耗和电流纹波,并拓宽了系统闭环带宽,提高了动态性能。设计了基于同步整流和耦合电感技术的20 W SEPIC数字直流电源,通过定性分析和定量比较,验证了理论分析的正确性。展开更多
基金Funded by the National Natural Science Foundation of China (No. 62004154)。
文摘The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied.We fabricated the PIN rectifier diodes with different initial oxygen concentrations,and analyzed the electrical properties,anisotropic preferred etching by means of optical microscopy,Fourier transform infrared spectroscopy and transmission electron microscopy.It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration.Furtherly,we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode.It is shown that the oxygen precipitations present in an "S" curve with increasing initial oxygen concentration after high temperature diffusion.The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF),which are mainly dislocations,and a small amount of rod stacking faults.The density of B-OSF increases with the increasing initial oxygen concentration.The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.
基金Project supported by the Program for New Century Excellent Talents in University,China(Grant No.NCET-10-0052)the Fundamental Research Funds for the Central Universities of China(Grant No.HEUCFT1008)
文摘A junction barrier Schottky （JBS） rectifier with an improved P-well on 4H-SiC is proposed to improve the VF-IR trade-off and the breakdown voltage. The reverse current density of the proposed JBS rectifier at 300 K and 800 V is about 3.3 × 10-s times that of the common JBS rectifier at no expense of the forward voltage drop. This is because the depletion layer thickness in the P-well region at the same reverse voltage is larger than in the P＋ grid, resulting in a lower spreading current and tunneling current. As a result, the breakdown voltage of the proposed JBS rectifier is over 1.6 kV, that is about 0.8 times more than that of the common JBS rectifier due to the uniform electric field. Although the series resistance of the proposed JBS rectifier is a little larger than that of the common JBS rectifier, the figure of merit （FOM） of the proposed JBS rectifier is about 2.9 times that of the common JBS rectifier. Based on simulating the values of susceptibility of the two JBS rectifiers to electrostatic discharge （ESD） in the human body model （HBM） circuits, the failure energy of the proposed JBS rectifier increases 17% compared with that of the common JBS rectifier.
基金supported by the International Thermonuclear Experimental Reactor Project of China(No.2008 GB104000)
文摘In nuclear fusion power supply systems, the thyristors often need to be connected in parallel for sustaining large current. However, research on the reverse recovery transient of parallel thyristors has not been reported yet. When several thyristors are connected in parallel,they cannot turn-off at the same moment, and thus the turn-off model based on a single thyristor is no longer suitable. In this paper, an analysis is presented for the reverse recovery transient of parallel thyristors. Parallel thyristors can be assumed as one virtual thyristor so that the reverse recovery current can be modeled by an exponential function. Through equivalent transformation of the rectifier circuit, the commutating over-voltage can be calculated based on Kirchhoff’s equation. The reverse recovery current and commutation over-voltage waveforms are measured on an experiment platform for a high power rectifier supply. From the measurement results, it is concluded that the modeling method is acceptable.
文摘单端初级电感变换器(SEPIC)是升-降压型变换器,具有输入电流脉动小、同极性输出和输入电压范围宽的优势,适用于诸如燃料电池、光伏发电等电压变化范围大的场合。简单介绍了SEPIC的工作原理,提出了应用同步整流和耦合电感技术的SEPIC数字电源,减少了整流器件的损耗和电流纹波,并拓宽了系统闭环带宽,提高了动态性能。设计了基于同步整流和耦合电感技术的20 W SEPIC数字直流电源,通过定性分析和定量比较,验证了理论分析的正确性。
