| 摘要 |
PURPOSE:To avoid the maldistribution of a load current within the range of the machine rating of a cycloconverter by a method wherein the deviation between a primary frequency and a speed command is detected and the output of an oscillator which starts output in accordance with the detecting operation is added to the speed command of an induction machine. CONSTITUTION:A primary frequency omega1 and a speed command omega are inputted to an adder/detector 5C and the deviation between them is calculated by the adder/detector 5C. The absolute value of the deviation is calculated by an absolute value calculating part 8 and outputted to a next stage. A comparator 9 having hysteresis compares the absolute value of the deviation with an internal set value and, if the absolute value of the deviation is smaller than the set value, operates an ON-delay timer 10 of the next stage. A triangular wave generator 11 outputs a triangular wave omegaT in accordance with the operation of the ON-delay timer 10 and the triangular wave having positive and negative polarities is added to the speed instruction of a winding type induction machine by an adder/detector 5A. |
