Insulation monitor and method for operating same

US12422464B2 · kind B2 · utility

Assignee

• Mercedes-Benz Group AG · DE

Inventors

• Markus ORNER · Renningen, DE
• Akin CANDIR · Bonlanden, DE
• Urs BOEHME · Ehningen, DE

Key dates

• Filing date: Jul 1, 2022
• Grant date: Sep 23, 2025
• Expiry date: Nov 15, 2042

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/52
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An insulation monitor for a high-voltage onboard electrical system of a motor vehicle is provided. A respective Y-capacitor is arranged between the positive potential and the vehicle earth and between the negative potential and the vehicle earth. The insulation monitor has a current or voltage source, a voltmeter for measuring at least one of the potentials, and is configured to apply a negative current by the current source when the potential measured by the voltmeter exceeds a predefined upper value and to apply a positive current by the current source when the potential measured by the voltmeter falls below a predefined lower value. The current thus being limited to a maximum permissible contact current in the case of an insulation fault and it is possible to infer the magnitude of the insulation resistances using the voltage measured by the voltmeter and the recharging current that has been fed in.