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SiC-MOSFETs have attracting increasing attention because of their outstanding characteristics that contributes to high efficiency and high power density of power converters. However, compared to conventional Si-IGBTs, SiC-MOSFETs are susceptible to false triggering, because they tend to generate large switching noise due to ultrafast switching capability and have a lower threshold voltage in high temperature operation. Particularly, disastrous oscillation of repetitive false triggering can occur after a fast turn-off, which is the severe issue for practical application of SiC-MOSFETs. The purpose of this paper is to give an instruction to avoid this phenomenon. This paper hypothesized that the repetitive false triggering is the parasitic oscillation caused by parasitic capacitance of SiC-MOSFET, and parasitic inductance of wiring. Based on this hypothesis, this paper analyzed the oscillatory condition of the parasitic oscillator to propose a design instruction to avoid the oscillatory false triggering. The result revealed that the parasitic inductance of the gate, drain, and source wiring should be designed so that the resonance frequency of the parasitic LC resonator in the gating circuit is far apart from that of the power circuit. This paper also presents experimental results that support appropriateness of the proposed design instruction.

InAs quantum dots (QDs) were grown on GaAs by molecular beam epitaxy using As 2 molecules (As 2 -QDs) and were structurally and optically characterized. Photoluminescence (PL) measurements revealed unique optical properties of the As 2 -QDs, which differ from InAs QDs grown with As 4 (As 4 -QDs). As 2 -QDs exhibited PL emission centered at 1.14–1.21 µm, which is shorter than that of As 4 -QDs (1.21–1.22 µm). In addition, the emission peak wavelength was continuously redshifted with a growth interruption time (Δt), which is an interval between the growth of the As 2 -QDs and capping of the QDs with a GaAs layer. Considering that no apparent difference of structural property was observed among as-grown As 2 -QDs and As 4 -QDs with various Δt, the peak shift can be attributed to the deformation of QDs during the capping process. The continuous peak shift can be applied to control the emission wavelength of InAs QDs, and this enables a broadband light source by combining the As 2 -QDs with different peak wavelengths.

This paper presents a novel control method for controlling the Modular Matrix Converter (MMxC) in order to achieve balanced capacitor voltages in addition to load voltage and input current control. The proposed control technique has been designed based on independent current control of positive-, negative- and zero-sequence in addition to feed forward power control. The positive-sequence circuit is used to control the input current, the negative-sequence circuit is used to balance the capacitor voltage among MMxC arms and the zero-sequence circuit is used to control the load control. Feed forward power control is used to suppress the capacitor voltage fluctuation. The effectiveness of the proposed control scheme for the MMxC has been verified theoretically using simulation software and experimentally using 4kVA–200V laboratory prototype.

This paper presents independent control of input current and output voltage for Modular Matrix Converter (MMxC). The MMxC is a multi-level converter without a transformer that converts from the high voltage AC to high voltage AC with arbitrary amplitude and frequency. The control method is difficult due to the simultaneous control of the input current and output voltage. The authors propose a novel control method that is divided into two parts of the positive-sequence circuit for the input current control, and the zero-sequence circuit for the output voltage control. The effectiveness of the proposed control method has been verified by simulations and experiments.