| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect an unstable condition of a power conversion device resulting from a small capacitance of a capacitor and a DC voltage oscillating under various conditions. <P>SOLUTION: A stability determination circuit 6 includes an average value acquisition circuit 12, a subtracter 13, a predetermined value setter 14, an absolute value acquisition circuit 15 and a comparator 16. The average value acquisition circuit 12 computes an average value Vdcb of a DC voltage Vdc. The subtracter 13 subtracts the average value Vdcb from the DC voltage Vdc to produce a pulsation component Vdcr of the DC voltage. The absolute value acquisition circuit 15 obtains an absolute value ¾Vdcr¾ of the pulsation component Vdcr. The predetermined value setter 14 outputs a predetermined value Q. The comparator 16 outputs a result of comparison of the predetermined value Q and the amplitude ¾Vdcr¾ of the pulsation component Vdcr as a stability determination signal J. The predetermined value Q assumes a fixed value, or a nonincreasing value with respect to an increase in the average value Vdcb. <P>COPYRIGHT: (C)2013,JPO&INPIT |
