Patent ID: 9041406
Filing Date: 2015-05-26
Classification: A61B,B60L,G01L,G01R,Y02T

Abstract:
1. An apparatus for detecting reduction in insulation resistance between a vehicle body and a high-voltage circuit, the apparatus comprising: a coupling capacitor electrically connected to the high-voltage circuit at a predefined point of the high-voltage circuit via a first terminal of the coupling capacitor; an oscillation circuit configured to apply an AC voltage of a predetermined frequency to a second terminal of the coupling capacitor through a predetermined output impedance; a determiner configured to determine reduction in insulation resistance between the vehicle body and the high-voltage circuit on the basis of a change in potential to ground at the second terminal of the coupling capacitor; a digital filter configured to remove noise included in the potential to ground to be forwarded to the determiner, the digital filter being electrically connected between the second terminal of the coupling capacitor and a signal input of the determiner; an aliasing suppression circuit configured to suppress aliasing in the digital filter, the aliasing suppression circuit being electrically connected between the second terminal of the coupling capacitor and a signal input of the digital filter, and the aliasing suppression circuit including a resistor electrically connected to the second terminal of the coupling capacitor; and a protection circuit configured to protect the determiner and the digital filter from high-voltage noise generated in the high-voltage circuit, the protection circuit being electrically disposed between the resistor of the aliasing suppression circuit and the signal input of the digital filter.