Due to the high‐speed switching, the switching process of a silicon carbide (SiC) metal oxide field effect transistor (MOSFET) in a practical circuit is susceptible to parasitics and exhibits ...significant current and voltage overshoots. This may subsequently lower the efficiency of the device, degrade the reliability of the system, increase the level of electromagnetic interference and prohibit the full utilization of SiC MOSFETs’ potential. Conventional qualitative analysis is difficult to support enough guidance to deal with the switching overshoots in practice. In order to implement quantitative analysis of the switching overshoots of SiC power electronic circuits, an analytical model of SiC MOSFET switching behaviour in the half‐bridge configuration was derived considering all important parasitic parameters, the non‐linear characteristics of the parasitic capacitances and the transconductance coefficient of the device. Based on the derived analytical model, the switching voltage and current overshoots under the specific circuit parameter conditions can be quantitatively evaluated without complex system‐level modelling. Sensitivity analysis for the voltage and current overshoots during the switching transient was quantified. Moreover, the effect rule of the gate resistance on the voltage overshoot was revealed. In the article, simulation and experimental results validate the analytical model and analysis results.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The gallium nitride transistors suffer from current collapse effect in operation regions, which leads the dynamic ON-resistance to increase when high voltage is applied to the transistor. Dynamic ...ON-resistance under practical application conditions is also an important factor for the reliability and conduction efficiency of transistors. To measure the dynamic ON-resistance and evaluate the current collapse effect, a softswitching circuit based on synchronous buck topology is proposed in this paper. To apply high-voltage and high-current stresses to the device without additional spikes and oscillation, resonance technique has been employed. As a result, the proposed circuit could produce sufficient power stresses to the devices with general equipment. To achieve accurate measurement of ON-resistance under switching operations and eliminate the saturation of oscilloscope probes, an active voltage clamp circuit is developed. Operation principles and design analysis of the circuit are described in this paper. The dynamic ON-resistance measurement method is illustrated in detail. Furthermore, a prototype circuit has been built. A simulation and experiments were carried out to verify the performance of the system. A comparison of the active clamp circuit with common voltage probes is presented through the measurement results. The experimental results confirm that dynamic ON-resistance can be accurately measured using the proposed circuit and the current collapse effect can be evaluated under practical operation conditions with high precision.
An embedded inductor constructed with Sendust powder composite films and embedded circuits is proposed. The composite films consist of mixed Sendust flaked powders and EPDM rubber. An embedded ...circuit is an etched spiral copper trace with 16 turns and two layers. Copper trace is patterned with a dimension of 0.025 mm thickness, 0.1 mm width, and 0.1 mm pitch. Regarding the performances of the proposed inductor, it was obtained that the simulated inductance and copper resistance are 4.7 uH and 770 mΩ, respectively, while the measured results are 5.0 uH and 720 mQ, respectively. Measurements also show that the proposed inductor has relative high permeability and quality factor in a wide range of frequencies. It was confirmed that inductance of this inductor has a good stability to high frequency. To verify the usefulness of this inductor, the embedded inductor with a flexibility and the dimension of 10 mm × 7 mm × 0.3 mm was applied to a step-up dc-dc converter that is fabricated in the flexible printed circuit. The output power of the fabricated dc-dc converter is 1.8 W (4.5 V/400 mA), and the switching frequency is 1.2 MHz. Finally, the fabricated dc-dc converter was tested and the maximum efficiency of 84% was obtained.
This paper proposes a novel test circuit for SiC transistors. On-state resistance underpractical application conditions is an important characteristic for the device reliability and ...conductionefficiency of SiC transistors. In order to measure the on-state resistance in practical applications, highvoltage is needed, and high current is also necessary to ignite performance for the devices. A softswitchingcircuit based on synchronous buck topology is developed in this paper. To provide highvoltageand high-current stresses for the devices without additional spikes and oscillations, a resonantcircuit has been introduced. Using the novel circuit technology, soft-switching can be successfullyrealized for all the switches. Furthermore, in order to achieve accurate measurement of on-stateresistance under switching operations, an active clamp circuit is employed. Operation principle anddesign analysis of the circuit are discussed. The dynamic measurement method is illustrated in detail.
Simulation and experiments were carried out to verify the feasibility of the circuit. A special testcircuit has been developed and built. Experimental results confirm that the proposed circuit gives agood insight of the devices performance in real applications. KCI Citation Count: 5
A high performance interleaved bridgeless boost power factor correction (PFC) rectifier operating under the critical current conduction mode (CrM) is proposed in this paper to improve the efficiency ...and system performance of various applications, such as nano-grid systems. By combining the interleaved technique with the bridgeless topology, the circuit contains two independent branches without rectifier diodes. The branches operate in interleaved mode for each respective half-line period.
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