The electronic transport properties of oligoacenes sandwiched between two Au（111） surfaces with serial and parrallel configurations were investigeted by using a fully self-consistent nonequilibrium Green＇s function...The electronic transport properties of oligoacenes sandwiched between two Au（111） surfaces with serial and parrallel configurations were investigeted by using a fully self-consistent nonequilibrium Green＇s function method combined with density functional calculations. This theoretical results show that the conductivity of oligoacenes with both sandwiched configurations at low bias voltage is mainly determined by the tail of the transmission peak from the perturbed highest occupied molecular orbital. When the molecular length increases, the zero-bias voltage conductance G（0） of oligoacenes with serial configuration neither follows Magoga＇s exponential law nor displays the even-odd oscillation effect, while the G（O） of the oligoacenes sandwiched with parallel configuration monotonically increases. The reduction of energy gaps, the alignment of the Fermi level, and the spatial distribution of the perturbed molecular orbitals are used to self-consistently explore the transport mechanism through oligoacenes.展开更多
A junction temperature monitoring method has been presented based on the on-state voltage at high currents.With a simplified physical model,this method mapped the relationship between junction temperature and on-state...A junction temperature monitoring method has been presented based on the on-state voltage at high currents.With a simplified physical model,this method mapped the relationship between junction temperature and on-state voltage.The tough calibration and signal sensing issues are solved.Verified by body-diode voltage detecting method,the presented method shows a good performance and high accuracy,in the meantime,it would not change the modulation strategy and topology of the converter.展开更多
The hybrid structure of a power-module package is summarized and classified.Basic and extended planar wire-bond designs are analyzed and compared with regular wire-bond modules and planar modules,respectively.The auto...The hybrid structure of a power-module package is summarized and classified.Basic and extended planar wire-bond designs are analyzed and compared with regular wire-bond modules and planar modules,respectively.The automatic layout method can improve the electrical and thermal performance of hybrid structures.A state-of-the-art hybrid structure is introduced,and suggestions for alleviating the current and temperature imbalances for future designs are provided.展开更多
In this paper,an offline evaluation method for the cooling capability of three-phase insulated-gate bipolar transistor(IGBT)inverters is presented,which can better emulate real working conditions.With a properly desig...In this paper,an offline evaluation method for the cooling capability of three-phase insulated-gate bipolar transistor(IGBT)inverters is presented,which can better emulate real working conditions.With a properly designed sudden-stop control sequence,the conventional junction temperature monitoring method at a low current is used to calculate the junction temperature before the sudden stop of an inverter.This can solve the challenging switching loss calculation issue in conventional methods.Finally,the feasibility,control sequence,and electrical behaviors of the proposed method are validated through experimental tests.展开更多
基金ACKNOWLEDGMENTS We thank Professor Wan-zhen Liang for helpful discussion. This work was completed in her group. This work was supported by the National Natural Science Foundation of China （No.20773112 and No.10674121）, the National Key Basic Research Program （No.2006CB922000）, the Science and Technological Fund of Anhui Province for Outstanding Youth （No.08040106833）, the USTC-HP HPC project, and the SCCAS and Shanghai Supercomputer Center.
文摘The electronic transport properties of oligoacenes sandwiched between two Au（111） surfaces with serial and parrallel configurations were investigeted by using a fully self-consistent nonequilibrium Green＇s function method combined with density functional calculations. This theoretical results show that the conductivity of oligoacenes with both sandwiched configurations at low bias voltage is mainly determined by the tail of the transmission peak from the perturbed highest occupied molecular orbital. When the molecular length increases, the zero-bias voltage conductance G（0） of oligoacenes with serial configuration neither follows Magoga＇s exponential law nor displays the even-odd oscillation effect, while the G（O） of the oligoacenes sandwiched with parallel configuration monotonically increases. The reduction of energy gaps, the alignment of the Fermi level, and the spatial distribution of the perturbed molecular orbitals are used to self-consistently explore the transport mechanism through oligoacenes.
基金Supported by the National Key Research and Development Program of China(2016YFB0100600)the Key Program of Bureau of Frontier Sciences and Education,Chinese Academy of Sciences(QYZDBSSW-JSC044).
文摘A junction temperature monitoring method has been presented based on the on-state voltage at high currents.With a simplified physical model,this method mapped the relationship between junction temperature and on-state voltage.The tough calibration and signal sensing issues are solved.Verified by body-diode voltage detecting method,the presented method shows a good performance and high accuracy,in the meantime,it would not change the modulation strategy and topology of the converter.
基金Supported in part by the National Key R&D Program of China(2021YFB2500600)in part by a CAS Youth Multidisciplinary Project(JCTD-2021-09)in part by the Strategic Piority Research Program of Chinese Academy of Sciences(XDA28040100)。
文摘The hybrid structure of a power-module package is summarized and classified.Basic and extended planar wire-bond designs are analyzed and compared with regular wire-bond modules and planar modules,respectively.The automatic layout method can improve the electrical and thermal performance of hybrid structures.A state-of-the-art hybrid structure is introduced,and suggestions for alleviating the current and temperature imbalances for future designs are provided.
基金Supported by the National Key Research and Development Program of China(2016YFB0100600).
文摘In this paper,an offline evaluation method for the cooling capability of three-phase insulated-gate bipolar transistor(IGBT)inverters is presented,which can better emulate real working conditions.With a properly designed sudden-stop control sequence,the conventional junction temperature monitoring method at a low current is used to calculate the junction temperature before the sudden stop of an inverter.This can solve the challenging switching loss calculation issue in conventional methods.Finally,the feasibility,control sequence,and electrical behaviors of the proposed method are validated through experimental tests.
