| 摘要 |
PROBLEM TO BE SOLVED: To correctly measure ground-fault resistance having a large resistance value by making a necessary measurement time longer even when a charging voltage of a flying capacitor is affected large by a Y capacitor of a high-voltage power source.SOLUTION: In a Vc1n measurement section A2 and a Vc1p measurement section A4, measured values (a), (b) of voltage are acquired at two different timing points shifting from each other in the same charging section. On the basis of the ratio of the acquired measured values (a), (b) at the two points, a ground-fault resistance value is calculated using a ground-fault resistance map. An influence of an applied voltage V0 can be excluded using the ratio of the measured value at the two points. At a timing of a short charging time, an influence of a difference in ground-fault resistance value is apt to appear since a gradient of rising of a charging voltage waveform is large. When a difference between a plus-side measured value and a minus-side measured value is large, only a smaller one is corrected and the calculation is performed.SELECTED DRAWING: Figure 1 |
