Power Conversion Device Short-Circuit Mode Control
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Solution Overview
Problem
Existing power conversion devices for electric vehicles face challenges in implementing a reliable short-circuit mode during system failures, particularly due to the need for redundant power supply circuits which increase device size and complexity, and the risk of direct current bus bar voltage exceeding safe levels.
Innovation Solution
A power conversion device with separate drive circuits for upper and lower arms, utilizing both high-voltage and low-voltage power supplies to ensure continuous operation and control of switching elements, even in the event of power supply errors, by switching between power sources based on error detection and voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant power supply circuits are provided for both high-voltage and low-voltage power supplies to ensure continuous operation during failures, then system reliability is improved, but device complexity and size increase
Solution Approach 1:
The power supply system is segmented into high-voltage and low-voltage independent paths, each with its own error detection and switching mechanism. This allows redundant functionality to be distributed rather than centralized, reducing overall complexity while maintaining reliability.
Solution Approach 2:
The system dynamically changes operational parameters by switching between high-voltage and low-voltage power supply modes based on detected error conditions. This parameter-based adaptation allows the system to maintain reliability without requiring both power supplies to be fully active simultaneously, reducing device complexity.
2Reliability
If separate drive circuits are provided for upper and lower arms with independent power supplies, then control reliability during short-circuit mode is improved, but device size increases
Solution Approach 1:
The drive circuit is segmented into upper-arm and lower-arm independent control paths, each with dedicated power supply error detection. This segmentation ensures that failures in one arm do not compromise the other, improving control reliability for short-circuit mode operation.
Solution Approach 2:
The error detection and switching control functions are merged into a unified control mechanism that manages both high-voltage and low-voltage power supply paths. This merging reduces the need for completely separate control circuits, thereby reducing device size while maintaining reliability.
3Object-affected harmful factors
If power supply error detection and automatic switching mechanisms are implemented, then system safety is improved, but device complexity increases
Solution Approach 1:
Error detection and switching mechanisms are implemented in advance to prevent harmful conditions rather than responding after failures occur. The system proactively monitors power supply status and automatically switches to safe operating modes before critical failures can develop, improving system safety.
Solution Approach 2:
The power supply system performs self-diagnosis and self-correction through automatic error detection and switching. When errors are detected in high-voltage or low-voltage power supplies, the system automatically transitions to alternative power paths without requiring external intervention, improving safety while minimizing the complexity of external monitoring systems.
Data Source
AI summary
A power conversion device, that includes a drive circuit 11a that drives a switching element 4 included in an upper-arm for one of three phases, a drive circuit 11b that drives a switching element 5 included in a lower-arm for the one phase, and a control circuit 9 that transmits a control signal to the drive circuits 11a, 11b, is provided. The power conversion device includes power supply circuits 12a, 12b that provide power to the drive circuits 11a, 11b, respectively, a low-voltage power supply 6 that supplies power to one of the power supply circuits, 12a, and a high-voltage power supply 1 that supplies power to the other of the power supply circuits, 12b. Accordingly, it is possible to reliably protect a system: by realizing minimal redundancy of the power supply, the power supply generation circuit, etc.; and by realizing the short-circuit mode at the time of error occurrence.