Three-Phase DAB Converter Open-Circuit Fault Location by Waveform Bias
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Solution Overview
Problem
Current systems for detecting open-circuit faults in three-phase Dual Active Bridge (DAB) converters lack the ability to identify fault locations, leading to potential damage and inefficiencies due to semiconductor and gate drive circuit failures.
Innovation Solution
A detailed waveform analysis and logic-based fault diagnosis method that identifies unique DC bias patterns in phase currents to detect and locate open-circuit faults in three-phase DAB converters, allowing for timely corrective action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waveform analysis and logic-based fault diagnosis are implemented to detect and locate faults, then fault detection capability is improved, but system complexity increases
Solution Approach 1:
The system uses its own existing current sensors and waveform data to detect faults, rather than requiring separate dedicated fault detection hardware. The logic-based diagnosis uses patterns from normal operation to identify fault conditions, making the system self-diagnostic without external assistance.
Solution Approach 2:
The fault detection method creates a logical model or pattern copy of normal waveform behavior, then compares actual waveforms against this model to detect deviations indicating faults. This avoids complex physical modeling while achieving reliable detection.
2Measurement precision
If detailed waveform analysis is performed to identify fault locations, then measurement precision is improved, but processing time increases
Solution Approach 1:
The system pre-establishes the expected waveform patterns and DC bias characteristics for normal operation. When a fault occurs, the system compares actual waveforms against these pre-established patterns, enabling rapid fault identification without extensive real-time analysis.
Solution Approach 2:
The fault detection focuses on specific critical features of the waveforms (such as DC bias patterns in phase currents) rather than analyzing every aspect of the waveform in detail. This selective analysis achieves sufficient precision for fault location while reducing processing requirements.
3Reliability
If fault detection systems are added to prevent damage, then reliability is improved, but device complexity increases
Solution Approach 1:
The current sensors and control system perform both their primary function of monitoring converter operation and the secondary function of fault detection. The same hardware infrastructure is used for both normal control and fault diagnosis, eliminating the need for separate dedicated fault detection components.
Solution Approach 2:
The system monitors its own operational parameters and automatically detects faults using its existing sensing and processing capabilities. No external monitoring equipment or additional complexity is required - the system is self-diagnostic.
Data Source
AI summary
A system and method of fault detection based on a detailed waveform analysis is presented for transient and steady-state fault operation of 3-Φ DAB converter. Main symptoms of the converter during normal and fault conditions have been identified and a unique pattern in DC bias of phase currents under fault mode is noted. The logic-based fault diagnosis scheme is used to detect the fault and identify the faulty transistor.