Power Transistor Fault Detection via Signal Comparison
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Solution Overview
Problem
Existing methods for testing power transistors, such as those described in U.S. Pat. No. 6,927,988, are inadequate as they may damage other components in the circuit due to the requirement of a power source and inability to disable the inverter/converter functionality once a fault is detected, and they fail to locate faults before high voltage is applied.
Innovation Solution
A system and method that includes a controller coupled to a power converter to reset fault flags, apply gate driver signals, and compare these signals with feedback signals to identify faults, providing a warning indication and disabling functionality if a fault is detected, thus preventing damage to other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power source is connected to the power inverter to supply power for testing IGBTs, then the testing method can detect and diagnose faults, but other power electronics components and the load may be damaged due to IGBT failure and/or wiring faults
Solution Approach 1:
The patent applies preliminary action by testing IGBTs before connecting the power source to the power inverter. The controller applies test signals to the IGBTs through the power converter, detects faults in advance, and prevents damage to other components by disabling the inverter functionality before high-voltage operation begins
Solution Approach 2:
The patent implements preliminary anti-action by detecting IGBT faults before power source connection and automatically disabling the inverter functionality. This preemptive measure counteracts the potential harmful effect of IGBT failure and wiring faults that could damage other power electronics components and the load
2Device complexity
If the testing method only indicates whether a fault exists, then the testing is simple, but it is incapable of locating the fault position and disabling the inverter/converter functionality
Solution Approach 1:
The patent applies feedback by having the controller receive feedback signals from the IGBTs during testing, compare these signals with expected values, and use this information to both detect the presence of faults and locate their positions. The controller also uses this feedback to disable inverter functionality when faults are detected
Solution Approach 2:
The patent applies segmentation by testing each IGBT individually through the power converter and identifying which specific IGBT has the fault. This segmented approach allows the system to locate the exact position of the fault among multiple IGBTs rather than merely indicating that a fault exists somewhere in the system
Data Source
AI summary
A method for testing a power converter having at least one power transistor is disclosed. The method may include receiving a power transistor test request, and resetting a fault flag for each power transistor, wherein the fault flag indicates a fault status associated with a corresponding power transistor. The method may also include applying a gate driver signal to each power transistor, receiving a feedback signal from each power transistor, and determining a difference between the gate driver signal and the feedback signal associated with a respective power transistor. The method may further include identifying a power transistor fault if the difference exceeds a threshold profile, and setting the fault flag for the power transistor on which a power transistor fault is identified.