Patent ID: 6134128
Filing Date: 2000-10-17
Classification: B60L,H02H,H02M

Abstract:
Method for protecting a high-performance power converter, wherein the high-performance power converter comprises a mains power converter connected to an intermediate direct voltage circuit having an intermediate circuit capacitor, and further comprises a second power converter, the mains power converter and the second power converter each being arranged as a bridge circuit and containing a plurality of IGBTs (Insulated Gate Bipolar Transistors) arranged in pairs in bridge arms, the method comprising the steps of:converting an alternating voltage from a mains power supply into a direct voltage;supplying the direct voltage to the second power converter via the intermediate direct voltage circuit equipped with the intermediate circuit capacitor;converting the direct voltage into an alternating voltage;when a destructive discharge of the intermediate circuit capacitor occurs via one of the bridge arms which has become continuously conductive, switching through at least one of the other bridge arms in the mains and second power converters to perform a relief break-through to limit destructions;continuously measuring the intermediate circuit voltage of the intermediate direct voltage circuit; andwhen the intermediate circuit voltage falls below a predefined threshold voltage during normal operation of the high-performance power converter, specifically switching through the other bridge arms;wherein the step of switching through the other bridge arms is performed only when the level drops below the threshold voltage and no routine discharge of the intermediate direct voltage circuit has been induced at the same time.