The concept of a capacitive MOSFET sensor using a SOI wafer for detecting vertical force applied to its floating gate was already reported by the authors. A MOSFET is fabricated on a SOI wafer, and the box oxide under the gate is removed to release the gate structure. This sensor detects the displacement of the movable gate electrode from changes in drain current, and this current can be amplified electrically by adding voltage to the gate, i.e., the MOSFET itself serves as a mechanical sensor structure. Following this, the present paper reports the fabrication of a practical test device and its preliminary characterization. The present paper also proposes a circuitry, which converts the drain current change to the voltage change while compensating the temperature change. The performance of this circuitry is confirmed by SPICE simulation. In accelerometer application, a comparatively heavy proof mass and thin supporting beams are necessary for increasing the sensitivity. For this purpose, a fabrication process of depositing a thick mass structure using electroplating is newly proposed.

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SUMMARY In this study, we developed a converter based on SiC (Silicon Carbide)‐MOSFET for use in ultra‐high‐speed elevators, with a reduced volume of 15% compared with the conventional converter. We succeeded in reducing the power loss of the converter unit by 56% compared to the conventional converter in one round trip under high temperature condition. Recently, because of their useful characteristics, wide‐gap semiconductors, such as SiC and GaN, have gained considerable attention for use in various applications in the power electronics systems. Therefore, we studied the use of a converter in elevator systems based on SiC‐MOSFET. We used a 1200 V/800 A SiC‐MOSFET module for the converter unit. We developed a prototype of the converter unit and the control panel by applying for the SiC‐MOSFET module for an ultra‐high‐speed elevator. As a result, the setting area of the control panel (main part) becomes less than 43% of the conventional panel. We tried to demonstrate the working of a 68‐kW elevator by applying the prototype control panel. Because of the characteristic of the switching loss of SiC‐MOSFET, the power loss of the converter unit has almost no dependence on temperature. An energy‐saving effect of approximately 17% was achieved in the total elevator system in one round trip under high‐temperature condition.