Power Converter Fault Switching for Higher Short-Circuit Current

Solution Overview

Problem

The short-circuit current supply capability of electric power converters is limited by the dimensioning of power semiconductor switches, leading to potential overdimensioning and increased costs, especially during short-circuit faults in grid-forming operations.

Innovation Solution

Operate controllable power semiconductor switches at a lower switching frequency during short-circuit faults to reduce losses and increase short-circuit current supply without altering the converter's dimensioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electric power converter is overdimensioned to provide sufficient short-circuit current, then the short-circuit current supply capability is improved, but the size and cost of the converter increase

Engineering Contradiction:

Improveshort-circuit current supply capabilityVSAvoidconverter size

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies dynamics by making the switching frequency adjustable rather than fixed. During normal operation, the converter operates at a first switching frequency for efficient power conversion. Upon detecting a short-circuit fault, the control system dynamically switches to a second, lower switching frequency that enables higher current delivery capability. This dynamic adaptation allows the converter to provide sufficient short-circuit current without requiring permanent overdimensioning of the power semiconductor switches.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the electric power converter is overdimensioned to provide sufficient short-circuit current, then the short-circuit current supply capability is improved, but the cost of the converter increases

Engineering Contradiction:

Improveshort-circuit current supply capabilityVSAvoidconverter cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies dynamics by making the switching frequency adjustable rather than fixed. During normal operation, the converter operates at a first switching frequency for efficient power conversion. Upon detecting a short-circuit fault, the control system dynamically switches to a second, lower switching frequency that enables higher current delivery capability. This dynamic adaptation allows the converter to provide sufficient short-circuit current without requiring permanent overdimensioning of the power semiconductor switches.

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If the switching frequency is reduced during short-circuit faults, then the semiconductor switch losses are reduced, but the normal operation performance may be affected

Engineering Contradiction:

Improvesemiconductor switch lossesVSAvoidnormal operation performance

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent applies dynamics by making the switching frequency adjustable rather than fixed. During normal operation, the converter operates at a first switching frequency for efficient power conversion. Upon detecting a short-circuit fault, the control system dynamically switches to a second, lower switching frequency that enables higher current delivery capability while reducing semiconductor switch losses. The system maintains optimal performance in both operating conditions through this dynamic adaptation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies periodic action by using different switching frequencies for different operational phases. The converter uses a higher switching frequency during normal periodic operation for efficient power conversion, and switches to a lower frequency during fault conditions. This periodic adaptation of the switching frequency allows the system to optimize for different operational requirements without compromising either normal performance or fault response.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12562636B2Method for operating electric power converter and electric power converter

Publication Date: 2026.02.24 ABB (SCHWEIZ) AG

AI summary

A method for operating an electric power converter, and an electric power converter including a plurality of controllable power semiconductor switches and configured to operate in a grid-forming mode of operation such that the controllable power semiconductor switches are operated at a first switching frequency, and in response to detecting a short-circuit fault in an AC network connected to the electric power converter provide an AC current of at least a predetermined magnitude to the AC network such that the controllable power semiconductor switches are operated at a second switching frequency, wherein the second switching frequency is lower than the first switching frequency.