| 摘要 |
PCT No. PCT/JP87/00663 Sec. 371 Date Jul. 12, 1988 Sec. 102(e) Date Jul. 12, 1988 PCT Filed Sep. 7, 1987 PCT Pub. No. WO88/02195 PCT Pub. Date Mar. 24, 1988.The present invention relates to an inverter apparatus which controls a rotation speed of an electric motor by varying a frequency of voltage being applied to an induction electric motor. A pulse width modulating signal is generated by comparing a modulated wave signal with a triangular wave signal. The modulated wave signal is obtained by amplifying an error between a magnetic flux command signal having a frequency proportional to a frequency command from an outside source and an integral of a voltage signal being applied to a motor, the voltage signal being an output voltage of an inverter part. The triangular wave signal is a carrier frequency signal of a non-audible frequency, but even if the carrier frequency is made to be an audible frequency, distortion of the output voltage can be minimized. Therefore, the inverter apparatus can drive the motor with low noise.
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