In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS pr...In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS process. By embedding a p+implant region into the drain of NMOS in the traditional LVTSCR, a reversed Zener diode is formed by the p+implant region and the n+bridge, which helps to improve the holding voltage and decrease the snapback region.The physical mechanisms of the LVTSCR and DC-LVTSCR are investigated in detail by transmission line pulse(TLP)tests and TCAD simulations. The TLP test results show that, compared with the traditional LVTSCR, the DC-LVTSCR exhibits a higher holding voltage of 6.2 V due to the embedded clamping diode. By further optimizing a key parameter of the DC-LVTSCR, the holding voltage can be effectively increased to 8.7 V. Therefore, the DC-LVTSCR is a promising ESD protection device for circuits with the operation voltage of 5.5–7 V.展开更多
Based on 2-D device simulations and mixed-mode transient simulations, DC and transient discharge characteristics of a usual diode string utilizing a standard CMOS process, and a diode string utilizing a triple-well CM...Based on 2-D device simulations and mixed-mode transient simulations, DC and transient discharge characteristics of a usual diode string utilizing a standard CMOS process, and a diode string utilizing a triple-well CMOS process, which can serve as an essential VDD-VSS clamp device for CMOS input ESD protection were compared. Transient discharge characteristics including peak voltages developed across gates oxides of transistors in input buffers, lattice heating inside ESD protection devices, and ratios of discharge current components at its peak inside the diode-string clamp were compared. DC standby current levels added per each input pad structure, which are the critical parameters determining usefulness of the devices, were also compared. We showed that the diode-string devices in comparison can serve successfully as a VDD-VSS clamp device for ESD protection by virtue of the dominant pnpn thyristor-related conduction mechanisms. Optimization of design parameters including anode-cathode contact spacing in each diode in the string, device width of the diode string, and number of diodes in the diode string was performed to present transient discharge and DC characteristics of some recommendable design examples, which can serve as a guideline in designing diode-string clamp devices.展开更多
The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems lik...The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems like decrease in motor speed due to load,high consumption of current and high ripple occurrence of ripples have reduced its preferences.The ultimate objective of this study is to control change in motor speed due to load variations.An improved Trans Z Source Inverter(ΓZSI)with a clamping diode is employed to maintain constant input voltage,reduce ripples and voltage overshoot.To operate induction motor at rated speed,different controllers are used.The conventional Proportional-Inte-gral(PI)controller suffers from high settling time and maximum peak overshoot.To overcome these limitations,Fractional Order Proportional Integral Derivative(FOPID)controller optimized by Gray Wolf Optimization(GWO)technique is employed to provide better performance by eliminating maximum peak overshoot pro-blems.The proposed speed controller provides good dynamic response and controls the induction motor more effectively.The complete setup is implemented in MATLAB Simulation to verify the simulation results.The proposed approach provides optimal performance with high torque and speed along with less steady state error.展开更多
In medium voltage-high power(MV-HP)applications,the high switching frequency of power converter will result in unnecessary energy losses,which directly affect efficiency.To resolve this issue,a novel finite control se...In medium voltage-high power(MV-HP)applications,the high switching frequency of power converter will result in unnecessary energy losses,which directly affect efficiency.To resolve this issue,a novel finite control set-model predictive control(FCS-MPC)with low switching frequency for three-level neutral point clamped-active front-end converters(NPC-AFEs)is proposed.With this approach,the prediction model of three-level NPC-AFEs is established inα-βreference frame,and the control objective of low average switching frequency is introduced into a cost function.The proposed method not only achieves the desired control performance under low switching frequency,but also performs the efficient operation for the three-level NPC-AFEs.The simulation results are provided to verify the effectiveness of proposed control scheme.展开更多
INTRODUCTION The treatment of small renal masses has shifted from radical nephrectomy to partial nephrectomy, in particular, laparoscopic partial nephrectomy. Renal artery clamping is often necessary to minimize hemor...INTRODUCTION The treatment of small renal masses has shifted from radical nephrectomy to partial nephrectomy, in particular, laparoscopic partial nephrectomy. Renal artery clamping is often necessary to minimize hemorrhage during resection in cases of partial nephrectomy. However, renal artery clamping may lead to greater incidence of renal malfunction after partial nephrectomy. Therefore, novel techniques which could both avoid renal artery occlusion and achieve adequate hemostasis are urgently required. Selective renal segmental artery clamping was one of several common methods that could achieve ＂zero ischemia.＂ At the same time, a number of reports about laser-assisted partial nephrectomy on humans using multiple kinds of outstanding coagulative specialties of lasers were published.展开更多
In this paper,a novel superjunction 4H-silicon carbide(4H-SiC)trench-gate insulated-gate bipolar transistor(IGBT)featuring an integrated clamping PN diode between the P-shield and emitter(TSD-IGBT)is designed and theo...In this paper,a novel superjunction 4H-silicon carbide(4H-SiC)trench-gate insulated-gate bipolar transistor(IGBT)featuring an integrated clamping PN diode between the P-shield and emitter(TSD-IGBT)is designed and theoretically studied.The heavily doping superjunction layer contributes to a low specific on-resistance,excellent electric field distribution,and quasi-unipolar drift current.The anode of the clamping diode is in floating contact with the P-shield.In the on-state,the potential of the P-shield is raised to the turn-on voltage of the clamping diode,which prevents the hole extraction below the N-type carrier storage layer(NCSL).Additionally,during the turn-off transient,once the clamping diode is turned on,it also promotes an additional hole extraction path.Furthermore,the potential dropped at the semiconductor near the trench-gate oxide is effectively reduced in the off-state.展开更多
提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开...提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 k W实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。展开更多
基金National Natural Science Foundation of China(Grant No.61504049)the China Postdoctoral Science Foundation(Grant No.2016M600361).
文摘In order to reduce the latch-up risk of the traditional low-voltage-triggered silicon controlled rectifier(LVTSCR), a novel LVTSCR with embedded clamping diode(DC-LVTSCR) is proposed and verified in a 0.18-μm CMOS process. By embedding a p+implant region into the drain of NMOS in the traditional LVTSCR, a reversed Zener diode is formed by the p+implant region and the n+bridge, which helps to improve the holding voltage and decrease the snapback region.The physical mechanisms of the LVTSCR and DC-LVTSCR are investigated in detail by transmission line pulse(TLP)tests and TCAD simulations. The TLP test results show that, compared with the traditional LVTSCR, the DC-LVTSCR exhibits a higher holding voltage of 6.2 V due to the embedded clamping diode. By further optimizing a key parameter of the DC-LVTSCR, the holding voltage can be effectively increased to 8.7 V. Therefore, the DC-LVTSCR is a promising ESD protection device for circuits with the operation voltage of 5.5–7 V.
文摘Based on 2-D device simulations and mixed-mode transient simulations, DC and transient discharge characteristics of a usual diode string utilizing a standard CMOS process, and a diode string utilizing a triple-well CMOS process, which can serve as an essential VDD-VSS clamp device for CMOS input ESD protection were compared. Transient discharge characteristics including peak voltages developed across gates oxides of transistors in input buffers, lattice heating inside ESD protection devices, and ratios of discharge current components at its peak inside the diode-string clamp were compared. DC standby current levels added per each input pad structure, which are the critical parameters determining usefulness of the devices, were also compared. We showed that the diode-string devices in comparison can serve successfully as a VDD-VSS clamp device for ESD protection by virtue of the dominant pnpn thyristor-related conduction mechanisms. Optimization of design parameters including anode-cathode contact spacing in each diode in the string, device width of the diode string, and number of diodes in the diode string was performed to present transient discharge and DC characteristics of some recommendable design examples, which can serve as a guideline in designing diode-string clamp devices.
文摘The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems like decrease in motor speed due to load,high consumption of current and high ripple occurrence of ripples have reduced its preferences.The ultimate objective of this study is to control change in motor speed due to load variations.An improved Trans Z Source Inverter(ΓZSI)with a clamping diode is employed to maintain constant input voltage,reduce ripples and voltage overshoot.To operate induction motor at rated speed,different controllers are used.The conventional Proportional-Inte-gral(PI)controller suffers from high settling time and maximum peak overshoot.To overcome these limitations,Fractional Order Proportional Integral Derivative(FOPID)controller optimized by Gray Wolf Optimization(GWO)technique is employed to provide better performance by eliminating maximum peak overshoot pro-blems.The proposed speed controller provides good dynamic response and controls the induction motor more effectively.The complete setup is implemented in MATLAB Simulation to verify the simulation results.The proposed approach provides optimal performance with high torque and speed along with less steady state error.
文摘In medium voltage-high power(MV-HP)applications,the high switching frequency of power converter will result in unnecessary energy losses,which directly affect efficiency.To resolve this issue,a novel finite control set-model predictive control(FCS-MPC)with low switching frequency for three-level neutral point clamped-active front-end converters(NPC-AFEs)is proposed.With this approach,the prediction model of three-level NPC-AFEs is established inα-βreference frame,and the control objective of low average switching frequency is introduced into a cost function.The proposed method not only achieves the desired control performance under low switching frequency,but also performs the efficient operation for the three-level NPC-AFEs.The simulation results are provided to verify the effectiveness of proposed control scheme.
文摘INTRODUCTION The treatment of small renal masses has shifted from radical nephrectomy to partial nephrectomy, in particular, laparoscopic partial nephrectomy. Renal artery clamping is often necessary to minimize hemorrhage during resection in cases of partial nephrectomy. However, renal artery clamping may lead to greater incidence of renal malfunction after partial nephrectomy. Therefore, novel techniques which could both avoid renal artery occlusion and achieve adequate hemostasis are urgently required. Selective renal segmental artery clamping was one of several common methods that could achieve ＂zero ischemia.＂ At the same time, a number of reports about laser-assisted partial nephrectomy on humans using multiple kinds of outstanding coagulative specialties of lasers were published.
基金the General Program of National Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0475)the Doctoral Research Start-up Fund of Chongqing University of Posts and Telecommunications(A2023-7)the Technology Innovation and Application Demonstration Key Project of Chongqing Municipality(cstc2019jszx-zdztzxX0005,cstc2020jscx-gksbX0011)。
文摘In this paper,a novel superjunction 4H-silicon carbide(4H-SiC)trench-gate insulated-gate bipolar transistor(IGBT)featuring an integrated clamping PN diode between the P-shield and emitter(TSD-IGBT)is designed and theoretically studied.The heavily doping superjunction layer contributes to a low specific on-resistance,excellent electric field distribution,and quasi-unipolar drift current.The anode of the clamping diode is in floating contact with the P-shield.In the on-state,the potential of the P-shield is raised to the turn-on voltage of the clamping diode,which prevents the hole extraction below the N-type carrier storage layer(NCSL).Additionally,during the turn-off transient,once the clamping diode is turned on,it also promotes an additional hole extraction path.Furthermore,the potential dropped at the semiconductor near the trench-gate oxide is effectively reduced in the off-state.
文摘提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 k W实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。
