Series-Connected IGBT Switch Modules With Parallel Redundancy
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Solution Overview
Problem
The series connection of IGBT modules in power converters reduces reliability due to increased failure risk when one module fails, leading to potential failure of the entire string, especially under overvoltage or overcurrent conditions.
Innovation Solution
A system and method where each switch module includes at least two parallel connected electronic switches, with a controller that turns on non-faulty switches from other modules in case of failure, ensuring continued operation by utilizing redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plurality of IGBT modules are connected in series to provide high voltage capability, then the voltage handling capacity is improved, but the reliability deteriorates due to increased failure risk
Solution Approach 1:
Each IGBT module is segmented into multiple parallel-connected electronic switches (e.g., three switches per module). This segmentation allows individual switches to be isolated upon failure while keeping other switches operational, preventing total module failure and maintaining system reliability during high-voltage operation
Solution Approach 2:
The controller is configured to detect switch failures in advance and automatically activate redundant parallel switches before the failure propagates through the series-connected string. This preliminary detection and response mechanism prevents cascading failures and maintains converter functionality throughout the high-voltage series configuration
2Reliability
If redundancy is introduced by adding parallel electronic switches within each module, then the reliability is improved through fault tolerance, but the device complexity increases
Solution Approach 1:
Multiple parallel electronic switches are merged within a single IGBT module package, sharing common control and protection circuitry. This merging approach provides redundancy and fault tolerance while avoiding the complexity of completely separate redundant modules, as the parallel switches operate under unified controller management
Data Source
AI summary
A method for controlling a plurality of series connected switch modules each including at least two parallel connected electronic switches, the method includes the step of, in response to failure of any electronic switch of one or more switch modules, turning on any non-faulty electronic switch of one or more faulty switch modules when the electronic switches of other non-faculty switch modules are controlled to be turned on.