DC Ring Bus EV Charging System Fault Isolation
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Solution Overview
Problem
Current electric vehicle charging systems using Low Voltage AC distribution face challenges with large cable sizes and high distribution losses, and centralized converter systems have lower reliability due to higher failure rates compared to transformers.
Innovation Solution
A DC electric vehicle charging system with a ring configuration for connecting DC buses and multiple power sources to ensure continuous power supply even in case of faults, utilizing converters with circuit breakers and isolators for fault isolation, and maintaining a higher voltage level for reduced cable sizes and losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LVAC distribution system is used for multiple DC chargers, then the system can supply power to multiple vehicles, but the cable sizes become particularly large and distribution losses increase
Solution Approach 1:
The patent changes the voltage level parameter from low voltage AC to medium voltage DC, and changes the distribution architecture from radial to ring configuration. This parameter change enables higher voltage operation (reducing current for the same power) and provides multiple paths for power flow, thereby reducing cable sizes and distribution losses while maintaining power supply to multiple DC chargers
2Area of stationary object
If centralized converter system is used, then the system becomes compact, but the reliability decreases due to higher failure rates of converters compared to transformers
Solution Approach 1:
The patent implements a ring configuration that dynamically adapts to converter failures. When a converter or cable fails, the system automatically reconfigures power flow through alternative paths in the ring, maintaining operational continuity. This dynamic adaptation preserves reliability while keeping the system compact through centralized converter placement
3Reliability
If ring configuration with multiple power sources is implemented, then system reliability is enhanced through fault isolation and continued power supply, but device complexity increases
Solution Approach 1:
The patent segments the distribution system into multiple independent zones with discrete circuit breakers at each converter location. This segmentation allows fault isolation to specific segments while maintaining power supply to other segments through the ring configuration. The modular segmentation manages complexity by creating manageable, independent units rather than a monolithic system
Data Source
AI summary
A system for charging multiple electric vehicles is provided. The system includes a first electrical converter that supplies DC power to a ring bus. The ring bus is separated into a plurality of DC buses by electrical breakers. Second converters are connected to the ring bus and convert the DC power supply to a DC voltage suitable for charging electric vehicles connected thereto.