Protective circuit for a frequency converter

US7529068B2 · kind B2 · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Norbert Huber · Erlangen, DE
• Simon Graf · Ulm, DE

Key dates

• Filing date: Apr 25, 2005
• Grant date: May 5, 2009
• Expiry date: May 10, 2026

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02M1/36
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The voltage of the intermediate circuit of a frequency converter is monitored, while the intermediate circuit is charged via charging resistors. When the voltage has not reached at least a reference voltage during a specific time constant, the charging process is interrupted prematurely. The reference voltage is selected to be considerably lower than the operating voltage of the intermediate circuit. The reference voltage may be less than half of the operating voltage of the intermediate circuit.