Abstract: An object of the invention is to provide a control device of an induction motor where an inverter circuit can be protected from overcurrent by stable current limitation operation not only at steady operation but also at rapid acceleration/deceleration or at regenerative braking. A current component calculation circuit calculates a first current component from primary current detected by a current detector and output frequency. A correction frequency calculation circuit calculates a frequency correction value using a current limit value and the first current component according to prescribed function calculation. A subtractor subtracts the frequency correction value from a primary frequency command value. A voltage component calculation circuit calculates a primary voltage component command value according to the subtracted output.

Abstract: A method for forming an amorphous semiconductor film, which comprises (a) a film-forming step of forming a semiconductor film having not more than 20 atomic percent of bound hydrogen to a thickness of 3 to 1000 .ANG., and (b) a modifying step of modifying the formed film, the steps being repeated multiple times.

Abstract: A DC-to-AC electric power converting apparatus including an invertor circuit having a plurality of switching elements, a transformer connected to the invertor circuit, and a cyclo-converter circuit for converting the frequency of the output from the transformer. A carrier signal generator is provided for generating a carrier signal of a predetermined frequency.

Abstract: A DC-to-AC electric power converting apparatus includes: an inverter circuit for converting DC electric power into AC electric power; a transformer connected to the inverter circuit; a cyclo-converter circuit for converting the frequency of the output from the transformer; a carrier signal generator for generating a carrier signal of a predetermined frequency; an inverter switching circuit for generating a signal for controlling the inverter circuit in synchronization with the carrier signal; a reference voltage signal generating circuit for generating a reference signal for the AC voltage to be transmitted from the cyclo-converter circuit; a first switching signal generating circuit for generating a switching signal in accordance with the reference voltage signal supplied from the reference voltage signal generating circuit and the carrier signal supplied from the carrier signal generator; and a cyclo-converter switching circuit for generating a signal for controlling the cyclo-converter circuit in accordanc

Abstract: A control system for an induction motor includes a power presumption circuit for presuming an electric energy F.sub.o, which is associated with a reactive power generated in the induction motor, on the basis of the numerical constants including the secondary winding resistance, the actual primary current and the actual rotation speed or angle of the induction motor. The electric energy F.sub.o is used to compensate for the change of the numerical constants of the induction motor, which is caused by the change in temperature.