An induction motor driving controller which can improve performance of elevators is studied. The controller has three features. First, it has an energy-saving control by which the induction motor stably generates motor torque at the maximum efficiency, regardless of the number of passengers boarding the car, even if both acceleration from a standstill and deceleration from steady state are done for any elevator. Second, it can suppress vertical vibrations of elevators while performing energysaving control. Third, it ensures good performance of elevators even when the source voltage is reduced due to an overload on the source sides.The controller is judged suitable for the drive system of elevators on the basis of simulations and experiments.

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This paper describes a high-density motor drive system in which the power transmission lines are formed by a multi-layer printed board, making it possible to reduce inductance of lines. The structure of the power transmission lines between the converter and the inverter is determined, based on calculations of the magnetic field distribution generated by the differential (normal) mode current, which leads to an increase in radiated emissions due to the common mode current. The printed power circuit is experimentally verified as an effective way to reduce the electric field intensity from the radiation.

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.

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