@article{zhou_qiu_wang_gao_liu_2018, title={Dynamic analysis of a planar multi-stage centrifugal pump rotor system based on a novel coupled model}, volume={434}, ISSN={["1095-8568"]}, DOI={10.1016/j.jsv.2018.07.041}, abstractNote={The coupled rotor-dynamics issue is always one of the most important and difficult research for multi-stage pump system due to the complexity of multiple fluid-induced forces and multi-degree of freedom rotor model. In this paper, the Reynolds equation of journal bearing is solved by the finite difference method and corresponding fluid-induced force is obtained by small parameter method. In addition, the dynamic coefficients of annular seal are calculated according to bulk-flow model and perturbation method. Furthermore, a novel rotor system model fully considering the coupled effects of bearing and seal is proposed by matrix manipulation method. Then the coupled rotor-dynamics for multi-stage pump system is investigated subsequently based on the novel model. Finally, the Lomakin effect of annular seal is studied in detail. The calculated results indicate that the fluid-induced force of seal exerting on the rotor system should not be ignored in the calculation of coupled dynamic characteristics. Smaller length and clearance of annular seal are good for the stability of coupled rotor system. Compared with asymmetric structure, the symmetric sealing structure has a larger stability margin on condition of ‘rigid rotor’ status. Moreover, the Lomakin effect on stability presents linear superposition property. The proposed method can provide valuable reference for the design and modeling of multi-dimensional matrix system.}, journal={JOURNAL OF SOUND AND VIBRATION}, author={Zhou, Wenjie and Qiu, Ning and Wang, Leqin and Gao, Bo and Liu, Dong}, year={2018}, month={Nov}, pages={237–260} }
 @misc{zhao_gao_jiang_zhang_wang_xu_nishiguchi_fukawa_hopkins_2017, title={Flexible epoxy-resin substrate based 1.2 kV SiC half bridge module with ultra-low parasitics and high functionality}, url={http://dx.doi.org/10.1109/ecce.2017.8096700}, DOI={10.1109/ecce.2017.8096700}, abstractNote={To take full advantages of Wide Bandgap power semiconductor devices, breakthroughs on power module development are heavily explored nowadays. This paper introduces a 1.2kV SiC half bridge intelligent power module utilizing 80μm flexible epoxy-resin as substrates instead of traditional Direct-bonded Copper, for better thermal-stress management and lower cost. The investigation on the flexible epoxy-resin material indicates that it has low leakage current even at 250 °C, and high thermal conductivity up to 8 W/mK. No bonding wires are applied in the half bridge power module, instead, double-side solderable SiC MOSFET and diodes are fabricated and utilized for low parasitics and double-side cooling function. To further decrease the entire parasitic inductance on the power loop, a “Stack Structure” is proposed in this work to vertically connect highside and lowside switches with lower interconnection path than traditional power module technology. Simulation indicates that the parasitic inductance on the power loop is less than 1.5 nH. More functionality is achieved by integrating the main power stage with gate driver circuits. Digital isolations are also included in the half bridge module, together with a Low Dropout regulator to eliminate the numbers of auxiliary power supply required by the power module. The size of the entire module is about 35mm × 15mm ×7mm. Electrical simulations and measurements, including leakage current, parasitic extractions, device characteristics, verified that the designed module can work properly with no degradation on the SiC devices, with 12ns turn-off and 48ns turn-on at 800V bus voltage, and 0.63 mJ, 0.23 mJ as turn-on and turn-off loss, respectively.}, note={\urlhttps://ieeexplore.ieee.org/document/8096700/}, journal={2017 IEEE Energy Conversion Congress and Exposition (ECCE)}, publisher={IEEE}, author={Zhao, Xin and Gao, Bo and Jiang, Yifan and Zhang, Liqi and Wang, Sizhen and Xu, Yang and Nishiguchi, Kenji and Fukawa, Yoshi and Hopkins, Douglas C.}, year={2017}, month={Oct}, pages={4011–4018} }
 @article{zhao_jiang_gao_nishiguchi_fukawa_hopkins_2017, title={Novel Polymer Substrate-Based 1.2 kV/40 A Double-Sided Intelligent Power Module}, ISSN={["0569-5503"]}, url={https://www.lens.org/011-940-927-881-704}, DOI={10.1109/ectc.2017.285}, abstractNote={Advanced power module packaging technology is currently being heavily investigated to take full advantage of Wide Band Gap (WBG) power semiconductor devices. As one of most widely applied power module technologies, intelligent power modules, typically for automotive industries, work well to achieve higher operating frequencies with lower losses by integrating gate driver circuits with power semiconductor devices. In this paper, a novel flexible polymer substrate-based intelligent power module is developed and characterized. By applying 80 µm-thick epoxy-resin based flexible dielectric as a substrate, the overall weight and volume of the power module is reduced, as well as the cost, compared with traditional direct bonded copper ceramic-based modules. The performance of the epoxy-resin based dielectric is investigated, and shows that the leakage current of the dielectric at >1.5 kV is less than 20 µA at 250 oC. Double-sided solderable 1.2 kV SiC MOSFETs and Schottky diodes are fabricated and applied in the module without bonding wires, significantly reducing the overall parasitic inductance to}, note={\urlhttp://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7999873 ; \urlhttp://xplorestaging.ieee.org/ielx7/7998598/7999654/07999873.pdf?arnumber=7999873}, journal={2017 IEEE 67TH ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE (ECTC 2017)}, author={Zhao, Xin and Jiang, Yifan and Gao, Bo and Nishiguchi, Kenji and Fukawa, Yoshi and Hopkins, Douglas C.}, year={2017}, pages={1461–1467} }