The Experts below are selected from a list of 4200 Experts worldwide ranked by ideXlab platform
Michael A E Andersen - One of the best experts on this subject based on the ideXlab platform.
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high efficiency isolated boost dc dc converter for high power low voltage fuel cell applications
IEEE Transactions on Industrial Electronics, 2010Co-Authors: Morten Nymand, Michael A E AndersenAbstract:A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc-dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing of the primary-switch voltage rating can thus be avoided, significantly reducing switch-conduction losses. Finally, silicon carbide rectifying Diodes allow fast Diode Turn-off, further reducing losses. Detailed test results from a 1.5-kW full-bridge boost dc-dc converter verify the theoretical analysis and demonstrate very high conversion efficiency. The efficiency at minimum input voltage and maximum power is 96.8%. The maximum efficiency of the proposed converter is 98%.
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a new approach to high efficiency in isolated boost converters for high power low voltage fuel cell applications
International Power Electronics and Motion Control Conference, 2008Co-Authors: Morten Nymand, Michael A E AndersenAbstract:A new low-leakage-inductance low-resistance design approach to low-voltage high-power isolated boost converters is presented. Very low levels of parasitic circuit inductances are achieved by optimizing transformer design and circuit lay-out. Primary side voltage clamp circuits can be eliminated by the use of power MOSFETs fully rated for repetitive avalanche. Voltage rating of primary switches can now be reduced, significantly reducing switch on-state losses. Finally, silicon carbide rectifying Diodes allow fast Diode Turn-off, further reducing losses. Test results from a 1.5 kW full-bridge boost converter verify theoretical analysis and demonstrate very high efficiency. Worst case efficiency, at minimum input voltage maximum power, is 96.8 percent and maximum efficiency reaches 98 percent.
Morten Nymand - One of the best experts on this subject based on the ideXlab platform.
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high efficiency isolated boost dc dc converter for high power low voltage fuel cell applications
IEEE Transactions on Industrial Electronics, 2010Co-Authors: Morten Nymand, Michael A E AndersenAbstract:A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc-dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing of the primary-switch voltage rating can thus be avoided, significantly reducing switch-conduction losses. Finally, silicon carbide rectifying Diodes allow fast Diode Turn-off, further reducing losses. Detailed test results from a 1.5-kW full-bridge boost dc-dc converter verify the theoretical analysis and demonstrate very high conversion efficiency. The efficiency at minimum input voltage and maximum power is 96.8%. The maximum efficiency of the proposed converter is 98%.
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a new approach to high efficiency in isolated boost converters for high power low voltage fuel cell applications
International Power Electronics and Motion Control Conference, 2008Co-Authors: Morten Nymand, Michael A E AndersenAbstract:A new low-leakage-inductance low-resistance design approach to low-voltage high-power isolated boost converters is presented. Very low levels of parasitic circuit inductances are achieved by optimizing transformer design and circuit lay-out. Primary side voltage clamp circuits can be eliminated by the use of power MOSFETs fully rated for repetitive avalanche. Voltage rating of primary switches can now be reduced, significantly reducing switch on-state losses. Finally, silicon carbide rectifying Diodes allow fast Diode Turn-off, further reducing losses. Test results from a 1.5 kW full-bridge boost converter verify theoretical analysis and demonstrate very high efficiency. Worst case efficiency, at minimum input voltage maximum power, is 96.8 percent and maximum efficiency reaches 98 percent.
Xiangning He - One of the best experts on this subject based on the ideXlab platform.
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interleaved converter with voltage multiplier cell for high step up and high efficiency conversion
IEEE Transactions on Power Electronics, 2010Co-Authors: Wuhua Li, Yi Zhao, Yan Deng, Xiangning HeAbstract:A novel interleaved high step-up converter with voltage multiplier cell is proposed in this paper to avoid the extremely narrow Turn-off period and to reduce the current ripple, which flows through the power devices compared with the conventional interleaved boost converter in high step-up applications. Interleaved structure is employed in the input side to distribute the input current, and the voltage multiplier cell is adopted in the output side to achieve a high step-up gain. The voltage multiplier cell is composed of the secondary windings of the coupled inductors, a series capacitor, and two Diodes. Furthermore, the switch voltage stress is reduced due to the transformer function of the coupled inductors, which makes low-voltage-rated MOSFETs available to reduce the conduction losses. Moreover, zero-current-switching Turn- on soft-switching performance is realized to reduce the switching losses. In addition, the output Diode Turn-off current falling rate is controlled by the leakage inductance of the coupled inductors, which alleviates the Diode reverse recovery problem. Additional active device is not required in the proposed converter, which makes the presented circuit easy to design and control. Finally, a 1-kW 40-V-input 380-V-output prototype operating at 100 kHz switching frequency is built and tested to verify the effectiveness of the presented converter.
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high step up soft switching interleaved boost converters with cross winding coupled inductors and reduced auxiliary switch number
Iet Power Electronics, 2009Co-Authors: Wuhua Li, Xiangning HeAbstract:An interleaved boost converter is proposed to extend the voltage gain and to reduce the switch voltage stress compared with the conventional interleaved boost converter in high step-up applications. With the topology variation, only one set of active clamp circuit is necessary for the interleaved two phases to recycle the leakage energy and to absorb the voltage spikes caused by the leakage inductance of the winding-coupled inductors. Both the main switches and the clamp switch of the proposed converter are ZVT soft switching performances during the whole switching transition, which minimises the switching losses. The output Diode Turn-off current falling rate is controlled by the leakage inductance, which alleviates the output Diode reverse-recovery problem and reduces the relative reverse-recovery losses. The experimental results based on a 40-380-V DC/DC prototype verify the effectiveness of the theoretical analysis.
Hoyoung Cha - One of the best experts on this subject based on the ideXlab platform.
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schottky barrier Diode embedded algan gan switching transistor
Semiconductor Science and Technology, 2013Co-Authors: Bongryeol Park, J G Lee, Jaegil Lee, Dongmyung Lee, Moonkyung Kim, Hoyoung ChaAbstract:We developed a Schottky barrier Diode (SBD) embedded AlGaN/GaN switching transistor to allow negative current flow during off-state condition. An SBD was embedded in a recessed normally-off AlGaN/GaN-on-Si metal-oxide-semiconductor heterostructure field-effect transistor (MOSHFET). The fabricated device exhibited normally-off characteristics with a gate threshold voltage of 2.8 V, a Diode Turn-on voltage of 1.2 V, and a breakdown voltage of 849 V for the anode-to-drain distance of 8 µm. An on-resistance of 2.66 mΩcm2 was achieved at a gate voltage of 16 V in the forward transistor mode. Eliminating the need for an external Diode, the SBD embedded switching transistor has advantages of significant reduction in parasitic inductance and chip area.
S Decoutere - One of the best experts on this subject based on the ideXlab platform.
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au free algan gan power Diode on 8 in si substrate with gated edge termination
IEEE Electron Device Letters, 2013Co-Authors: Silvia Lenci, Brice De Jaeger, L Carbonell, G Mannaert, D Wellekens, Shuzhen You, Benoit Bakeroot, S DecoutereAbstract:High-performance AlGaN/GaN Diodes are realized on 8-in Si wafers with Au-free CMOS-compatible technology. The Diodes are cointegrated on the same substrate together with the AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors and with only one extra lithographic step. The Diode anode and the transistor gate are processed together and the same metallization is used for both, avoiding extra metal deposition dedicated to the Schottky junction. A gated edge termination allows obtaining low reverse leakage current (within 1 μA/mm at -600 V), which is several orders of magnitude lower than the one of conventional Schottky Diodes processed on the same wafer. Recess is implemented at the anode, resulting in low Diode Turn-on voltage values.