IGBT Fault Detection via Gate Feedback Timing
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Solution Overview
Problem
Series-connected insulated gate bipolar transistors (IGBTs) face challenges in fast and accurate fault detection, leading to potential voltage unbalance and reliability issues due to the failure of any single IGBT, which can cause abnormal operation and damage to the overall phase legs.
Innovation Solution
An assembly comprising series-connected IGBTs coupled with a failure mode detection unit that analyzes the timing sequence of gating and feedback signals to differentiate between common faults such as gate driver faults, failed turn-on faults, short-circuit faults, and over-voltage faults, enabling quick identification of fault type and location, and sending appropriate fault clearance signals to address these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If series-connected IGBTs are used for high voltage power conversion, then the power handling capability is improved, but the reliability deteriorates due to voltage unbalance and potential damage to phase legs from single IGBT failure
Solution Approach 1:
The patent implements preliminary fault detection by continuously monitoring the timing sequence of gating and feedback signals from each IGBT. The detection unit compares actual timing sequences against expected sequences to identify deviations indicating potential failures before they cause voltage unbalance or damage to phase legs, enabling preventive action rather than waiting for actual failure
2Reliability
If fast and accurate fault detection is implemented for series-connected IGBTs, then the reliability is improved, but the device complexity increases due to additional detection circuits and signal analysis requirements
Solution Approach 1:
The patent employs feedback mechanisms where the timing of feedback signals from each IGBT is continuously monitored and compared against expected timing sequences. The detection unit uses this feedback information to identify faults by detecting timing deviations, enabling reliable fault detection through systematic analysis of signal timing patterns without requiring overly complex additional hardware
Solution Approach 2:
The patent segments the fault detection function by individually monitoring each IGBT's gating and feedback signal timing sequences separately. This segmentation allows the detection unit to identify which specific IGBT in the series connection has failed and determine the fault type, providing precise fault location and classification without requiring a single monolithic complex detection system
Data Source
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AI summary
An assembly including an insulated gate bipolar transistor (IGBT) is provided. The IGBT is coupled with a gate driver (102) for receiving a gating signal (Gl) to drive the IGBT and providing a feedback signal (FB1) of the IGBT which indicates a change of a collector-emitter voltage of the IGBT. The assembly further includes a failure mode detection unit (104) for determining whether the IGBT is faulted based on a timing sequence of the gating signal (G1) and feedback signal (FB1). The failure mode detection unit (104) is capable of differentiating fault types including a gate driver fault, a failed turn-on fault, a short-circuit fault, a turn-on over-voltage fault and a turn-off over-voltage fault. Accordingly, an IGBT failure mode detection method is also provided.