| 摘要 |
PURPOSE:To restraint he fluctuation of control characteristics, by a method wherein whether operation is finished within a predetermined operating period or not is decided and a preset gain is corrected when the time of the operation exceeds the predetermined operating period. CONSTITUTION:A converter control circuit is constituted of a proportional integration circuit 6 of a DC voltage, supplied to an induction motor through a converter circuit, and another DC voltage, supplied to the induction motor through an inverter and returned to the converter through the feedback of the same voltage, another proportional integration circuit 7 of a feedback current from a smoothing capacitor and an ignition angle outputting circuit 8. In this case, the converter circuit is provided further with proportional integration circuit 9, 10, an operating time measuring circuit 11 and switches 13, 14. The measuring circuit 11 checks the count value of an IT counter by a predetermined measuring timing and decides whether an operating time is exceeded. According to this constitution, said measuring circuit 11 outputs a switching command 12 to switch to another proportional integration circuit having a different operating period constant by the switches 13, 14 when the operating time is exceeded so as to correct the deviation of a gain.
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