Flying Capacitor Converter Short-Circuit Isolation Circuit
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Solution Overview
Problem
In flying capacitor converters, short-circuits can generate large currents that lead to overcurrent and thermal damage, posing risks of accidents or fires, as existing systems lack effective short-circuit protection mechanisms.
Innovation Solution
Incorporating a current detection unit and a controller that disconnects the power switch unit from the high-voltage or low-voltage side when a short-circuit is detected, using low-current electronic components to reduce volume, cost, and power loss, and enhance safety by preventing large short-circuit currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple flying capacitor converters are connected in parallel to increase output power, then the output power of the system is improved, but the risk of short-circuit accidents and the magnitude of short-circuit current increase
Solution Approach 1:
The patent introduces a current detection unit as an intermediary between the flying capacitor converters and the common bus. This detection unit monitors current in real-time and provides early warning of short-circuit conditions, enabling preventive action before large short-circuit currents develop. The intermediary detection mechanism allows the system to maintain parallel converter connections for high power output while mitigating the harmful short-circuit current risk through early detection and isolation.
2Measurement precision
If conventional current detection methods are used in high-voltage sides, then accurate current detection is achieved, but the volume, cost and power loss of detection components increase
Solution Approach 1:
The patent extracts the current detection function from the high-voltage side to the low-voltage side through the common node. By detecting current at the low-voltage common node instead of directly at high-voltage points, the system achieves accurate short-circuit detection while using low-voltage, low-current electronic components. This extraction principle reduces the volume, cost, and power loss of detection components while maintaining detection effectiveness.
Solution Approach 2:
The patent replaces high-voltage mechanical or high-power electronic detection components with low-voltage electronic detection components. By substituting the detection location and method, the system uses smaller, cheaper, and more efficient low-voltage electronic components instead of bulky high-voltage detection equipment, reducing overall device complexity while maintaining measurement precision.
3Reliability
If high-current components are used for current detection and switching, then adequate current handling capability is ensured, but power loss and heat dissipation increase
Solution Approach 1:
The patent extracts the current detection and switching functions from high-current paths to low-current paths through the common node. By performing detection and switching operations at the low-voltage common node where current is lower, the system uses low-current components that inherently have lower power loss and heat dissipation while maintaining adequate current handling capability through the power switch units that remain connected to high-voltage sides.
Solution Approach 2:
The patent applies different current handling requirements to different parts of the system. The current detection unit and current switch units operate at low current on the low-voltage side, while the power switch units handle high current on the high-voltage side. This local differentiation allows each component to be optimized for its specific current level, reducing overall power loss and heat dissipation while maintaining system reliability.
Data Source
AI summary
A flying capacitor converter, a voltage converter and an energy storage system are provided. The flying capacitor converter includes a high-voltage side, a low-voltage side, a power switch unit, a current switch unit and a current detection unit. The high-voltage side is electrically connected with a first power source. The low-voltage side is electrically connected with a second power source. The power switch unit is electrically connected between the high-voltage side and the low-voltage side and includes three terminals and four power switches. The current switch unit is electrically connected with the high-voltage side, the low-voltage side and/or a common node. The current detection unit is electrically connected between a third terminal of the power switch unit and the common node. If the current detected by the current detection unit indicates that a short-circuit condition occurs, the power switch unit is disconnected from the high-voltage side and/or the low-voltage side.