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Mao Saijun,Wang Huizhen,Yan Yangguang The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrical Mach Vol.b5 No.4
This paper proposes a novel zero-voltage-switching (ZVS) Push-pull DC-DC Converter for high input voltage and high power applications. This topology utilizes two switches in series to replace one switch in conventional push-pull converter, and two clamping diodes are introduced. The voltage stress of the switches is the input voltage, and the switches can realize ZVS with the use of the leakage inductance of the transformer. Furthermore, secondary full-wave rectifier with a clamping capacitor is used to eliminate the voltage oscillation and spike of the rectifier diodes due to the reverse recovery. Therefore, the electromagnetic interference is reduced effectively. The operation principle of the proposed converter is analyzed theoretically. The output characteristic, ZVS condition and design principle of the clamping capacitor are discussed. Experimental results obtained from a 270V input 2kW prototype with $95.8\%$ high efficiency confirms the design.
Qin, Haihong,Ma, Ceyu,Zhu, Ziyue,Yan, Yangguang The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4
Parasitic parameters have a larger influence on Silicon Carbide (SiC) devices with an increase of the switching frequency. This limits full utilization of the performance advantages of the low switching losses in high frequency applications. By combining a theoretical analysis with a experimental parametric study, a mathematic model considering the parasitic inductance and parasitic capacitance is developed for the basic switching circuit of a SiC MOSFET. The main factors affecting the switching characteristics are explored. Moreover, a fast-switching double pulse test platform is built to measure the individual influences of each parasitic parameters on the switching characteristics. In addition, guidelines are revealed through experimental results. Due to the limits of the practical layout in the high-speed switching circuits of SiC devices, the matching relations are developed and an optimized layout design method for the parasitic inductance is proposed under a constant length of the switching loop. The design criteria are concluded based on the impact of the parasitic parameters. This provides guidelines for layout design considerations of SiC-based high-speed switching circuits.
Haihong Qin,Ceyu Ma,Ziyue Zhu,Yangguang Yan 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4
Parasitic parameters have a larger influence on Silicon Carbide (SiC) devices with an increase of the switching frequency. This limits full utilization of the performance advantages of the low switching losses in high frequency applications. By combining a theoretical analysis with a experimental parametric study, a mathematic model considering the parasitic inductance and parasitic capacitance is developed for the basic switching circuit of a SiC MOSFET. The main factors affecting the switching characteristics are explored. Moreover, a fast-switching double pulse test platform is built to measure the individual influences of each parasitic parameters on the switching characteristics. In addition, guidelines are revealed through experimental results. Due to the limits of the practical layout in the high-speed switching circuits of SiC devices, the matching relations are developed and an optimized layout design method for the parasitic inductance is proposed under a constant length of the switching loop. The design criteria are concluded based on the impact of the parasitic parameters. This provides guidelines for layout design considerations of SiC-based high-speed switching circuits.
Yang, Guang,Yan, Jing,Jeong, Young Gyu,Lee, Jong Keun Elsevier Science Ltd 2017 Composites Applied science and manufacturing Vol. No.
<P><B>Abstract</B></P> <P>This work reports the solvent-soluble multi-walled carbon nanotubes (MWCNTs), which can be used for the fabrication of ring-opening metathesis polymerization (ROMP)-based nanocomposites by solution casting technique. As the first and most important step of the solution casting technique, the excellent dispersibility of the MWCNTs in different solvents is achieved by the functionalization of the nanotube surface with norbornene oligomers. The norbornene-functionalized MWCNTs (nMWCNTs) have outstanding dispersion stability in water, tetrahydrofuran (THF), acetone, and ethanol, especially the maximum nanotube concentration of 3.9mg/mL in THF. The incorporation of nMWCNTs into poly(5-ethylidene-2-norbornene) (poly(ENB)) by solution casting technique results in significant improvements in the mechanical properties over the neat poly(ENB) and the pristine MWCNT-reinforced poly(ENB) nanocomposites. The route developed here not only avoids the dramatic increase of the viscosity occurring in the bulk polymerization but also provides the feasibility of high loadings of MWCNT reinforcements, consequently broadening the potential applications of ROMP-based nanocomposites.</P>