Patent ID: 8760172

Claim:
An insulation measurement apparatus for charging a flying capacitor by a voltage of a power supply and for measuring an insulation resistance between a positive electrode of the power supply and a ground potential and an insulation resistance between a negative electrode of the power supply and the ground potential, comprising: a high voltage measurement section which charges the flying capacitor by the voltage of the power supply without passing the insulation resistances for measuring a charged voltage of the flying capacitor; a ground resistor voltage measurement section which charges the flying capacitor by the voltage of the power supply via the insulation resistance between the positive electrode and the ground potential or the negative electrode and the ground potential for measuring the charged voltage of the flying capacitor; and an insulation resistance calculation section which obtains the insulation resistances based on the voltage measured by the high voltage measurement section, the voltage measured by the ground resistor voltage measurement section, and an insulation resistance conversion expression, wherein the flying capacitor is a ceramic capacitor, and wherein a charge time period of the flying capacitor by the high voltage measurement section is set to be same as a charge time period of the flying capacitor in the ground resistor voltage measurement section.