Charging Switch-Off Circuit for Fast EV Fault Current Interruption
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Solution Overview
Problem
Existing charging systems for electric vehicles lack effective mechanisms to prevent damage from excessive charging amperage and voltage, leading to fuse tripping and functional loss, especially during malfunctions, and are not adaptable to various vehicle fuses with different tripping characteristics.
Innovation Solution
A switch-off unit with controllable power semiconductor components and a diode arrangement, capable of rapidly interrupting charging current based on acquired charging parameters, allowing autonomous operation and adaptable threshold settings for different vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are used to interrupt charging current in case of malfunction, then the supply circuit can be protected, but the fuse must be replaced after just a few switching operations and the electric vehicle becomes non-functional
Solution Approach 1:
The patent replaces the mechanical fuse system with an electronic switch-off unit based on power semiconductor components. This electronic system can be reset and reused indefinitely, eliminating the need for physical fuse replacement while maintaining protection functionality. The switch-off unit uses controllable semiconductor switches instead of sacrificial fuses.
Solution Approach 2:
The patent changes the operational parameter of the protection mechanism from single-use (fuse) to multi-use (semiconductor switch). The power semiconductor components can be switched on and off repeatedly without degradation, allowing the same component to perform multiple protection operations rather than requiring replacement after one trip.
2Reliability
If fuses with long reaction time are used in power supply device, then the fuse can provide protection, but both the power supply device fuse and the electric vehicle fuse are tripped
Solution Approach 1:
The patent replaces the slow mechanical/thermal fuse operation with fast electronic detection and switching. The switch-off control device continuously monitors charging parameters and can detect malfunctions in microseconds, much faster than thermal fuses that rely on heat accumulation. This electronic system interrupts the fault current before it propagates to both fuses.
Solution Approach 2:
The patent implements preliminary protection by detecting charging parameter anomalies before they escalate to levels that would trip both fuses. The switch-off control device monitors voltage, current, and other parameters in real-time and interrupts charging at the first sign of malfunction, preventing the condition from developing into a dual-fuse trip scenario.
3Adaptability or versatility
If the power supply device charges various electric vehicles, then the device can serve multiple vehicle types, but the power supply device does not know the tripping characteristics of the fuse
Solution Approach 1:
The patent replaces fuse-based protection with an electronic switch-off system that actively monitors charging parameters. Instead of relying on passive fuse characteristics that vary by vehicle type, the electronic system dynamically adjusts protection thresholds based on real-time measurements, making it adaptable to different vehicle types without needing to know their specific fuse characteristics.
Solution Approach 2:
The patent implements feedback control where the switch-off control device continuously monitors charging parameters and adjusts its operation accordingly. The system measures actual voltage, current, and power levels during charging and uses this feedback to determine when to interrupt charging, adapting to different vehicle requirements without requiring pre-programmed knowledge of specific fuse trip characteristics.
Data Source
AI summary
The invention relates to a switch-off unit for an electric charging device with a [switch-off arrangement] having a first controllable power semiconductor component, a second controllable power semiconductor component and a diode, and a switch-off control device, whereinthe first power semiconductor component and the second power semiconductor component are arranged antiserially, whereinthe diode, the first power semiconductor component and the second power semiconductor component are arranged as a T-circuit, whereinthe first power semiconductor component and the second power semiconductor component are configured to conduct a charging current of the charging device in a switched-on state, whereinthe switch-off control device is operatively connected to the first power semiconductor component and the second power semiconductor component and is configured for their respective control, whereinthe switch-off control device is configured to acquire a value of at least one charging parameter which is characteristic of the charging current, andin dependence on the acquired value, to switch off the first power semiconductor component and/or the second power semiconductor component and thereby interrupt the charging current.