Three-Phase DAB Converter Fault Detection by Phase Current DC Bias
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for detecting open-circuit faults in three-phase Dual Active Bridge (DAB) converters lack effective methods to identify the fault location, relying on assumptions that the fault location is known.
Innovation Solution
A detailed waveform analysis is conducted to identify unique patterns in DC bias of phase currents under fault conditions, enabling a logic-based fault diagnosis method to detect and identify the faulty transistor in a three-phase dual active bridge converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waveform analysis and logic-based diagnosis are implemented to identify fault location, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses its own existing current sensors and waveform data to detect and diagnose faults, without requiring external diagnostic equipment. The controller analyzes phase current waveforms that are already being monitored for power conversion purposes, turning existing system resources into a self-diagnostic capability that improves reliability without adding external complexity
Solution Approach 2:
The patent replaces complex hardware-based fault detection methods with a logic-based software analysis approach. By using logical analysis of current waveform patterns (DC bias detection) instead of additional physical sensors or complex diagnostic circuitry, the system achieves reliable fault identification while minimizing added device complexity
2Measurement precision
If detailed waveform analysis is conducted to identify fault patterns, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system continuously monitors and analyzes phase current waveforms in real-time during normal operation, maintaining a ready state for fault detection. By having the diagnostic logic prepared and actively analyzing waveforms beforehand, the system can immediately identify faults when they occur without requiring time-consuming post-fault analysis, thus achieving both high precision and fast detection
Solution Approach 2:
The patent focuses on detecting specific key patterns (DC bias in phase currents) rather than analyzing every aspect of the waveform in detail. By concentrating diagnostic efforts on the most indicative fault signature, the system achieves sufficient measurement precision for fault identification while minimizing the time required for analysis compared to comprehensive waveform examination
Data Source
Figure 1
Figure 2
Figure 3
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.