Patent ID: 10890627

Abstract:
A ground fault detection apparatus is configured to be connected to an ungrounded battery for supplying power to a load via a step-up circuit and to detect ground fault by calculating an insulation resistance of a system provided with the battery, and includes a capacitor that operates as a flying capacitor, a set of switches that switch between a first voltage measurement path including the battery and the capacitor, a second voltage measurement path including the battery, the capacitor and a negative-electrode-side insulation resistor as an insulation resistor between a negative-electrode side of the battery and a ground, a third voltage measurement path including the battery, the capacitor and a positive-electrode-side insulation resistor as an insulation resistor between a positive-electrode side of the battery and the ground, and a capacitor charge voltage measurement path, and a pair of Form C contact relays that can reverse connection direction of the capacitor.