In order to further improve the device utilization of a modular inverter system after the failure of a single inverter unit, a silicon (Si)/silicon-carbide (SiC) hybrid switch with high redundancy can be taken to achieve this goal. However, when the failure of the Si/SiC hybrid switches in the inverter unit occurs, the performance of this modular inverter adopting the fixed switching strategy (Fixed switching pattern and switching frequency) may be reduced. In this paper, a redundancy management strategy is proposed to prevent the performance of the Si/SiC hybrid switch-based modular inverter from reducing after the failure of the Si/SiC hybrid switches occurs. Taking the modular inverter system composed of two inverter units as an example, the experiment results demonstrate that compared to the healthy operating conditions, the increase of the voltage’s THD is smaller than 1.4%, and the increase of the total loss is smaller than 0.89%.
A timing reference incorporating a single-crystal-silicon micromechanical resonator with a quality factor of larger than one million and a resonant frequency of 2.18 MHz is demonstrated. The resonator is excited in the square extensional bulk acoustic mode at 4 mtorr, and it has been fabricated in a foundry SOI MEMS process. The silicon microresonator is adapted as a timing element for a precision oscillator with a measured short-term Allan deviation of 0.6 ppb.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
This paper presents a new type of thermally actuated switch for wireless communication system operated at low gigahertz frequencies. The switch is driven by a metal electrothermal actuator, which can generate large displacement and high contact force at lower temperatures. The MEMS switch utilizing the parallel four-beam actuator requires driving voltage of 0.07 V for an 8 μm displacement. RF performances are improved by suspending the structure 25 μm from the substrate using MetalMumps process. An ON state insertion loss of -0.27 dB at 10 GHz and an OFF state isolation of -40 dB at 10 GHz are achieved on low resistivity silicon substrate.
This article presents the design and characterization of a direct current (dc) sensor utilizing the Hall effect in AlGaN/GaN 2-D electron gas (2DEG) four-terminal devices and a flux concentrator. The sensor was fabricated from an AlGaN/GaN/Si wafer grown by metal-organic chemical vapor deposition. The sensor exhibited excellent linearity and repeatability with a high Hall voltage under the primary current ranging from −5 to 5 A. The sensitivity of the sensor was measured to be 0.26 (V/A)/A at 20 °C and independent of ambient temperature up to 200 °C. The obtained result is greater than that of other reported Hall effect-based current sensors. The high sensitivity and thermal stability at varying temperatures are attributed to the high electron mobility, wide bandgap, and stability of carrier density in 2DEG. Combining these factors with the excellent mechanical strength, electrical conductivity, and chemical inertness of GaN, the proposed sensor is promising for current monitoring in a wide range of operation temperatures.
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