Semiconductor Switch-Off Unit for Fast EV Charging Current Interruption
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Solution Overview
Problem
Existing charging systems for electric vehicles lack efficient and timely protection against overcharging, leading to damage from excessive current or voltage, and require manual replacement of fuses, which disrupt vehicle functionality.
Innovation Solution
A switch-off unit with controllable power semiconductor components, configured to monitor and interrupt charging current based on specific parameters, allowing rapid response to malfunctions and preventing damage by autonomously controlling the charging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are used to interrupt the supply circuit in the event of a malfunction, then the charging current is interrupted to prevent damage, 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 substitution eliminates the need for mechanical fuse replacement while maintaining protection functionality. The power semiconductor components can be electronically controlled to interrupt the charging current and can be reset without physical replacement, thus resolving the contradiction between reliable protection and ease of repair.
Solution Approach 2:
The switch-off unit is designed to autonomously detect malfunctions and interrupt the charging current without requiring manual intervention. The system monitors charging parameters and automatically triggers the power semiconductor components to switch off when abnormal conditions are detected, providing self-service protection that eliminates the need for fuse replacement by the user.
2Reliability
If fuses with long reaction time are used in the power supply device, then the fuse can be protected, but both the power supply device fuse and the electric vehicle fuse are tripped and the reaction time is too long
Solution Approach 1:
The switch-off unit continuously monitors charging parameters during the charging process and is prepared to interrupt the charging current immediately when a malfunction is detected. This preliminary monitoring and readiness to act eliminates the delay inherent in traditional fuse operation, allowing the system to respond faster than the fuse reaction time while still providing protection.
Solution Approach 2:
By replacing the thermal-magnetic fuse mechanism with electronic monitoring and power semiconductor switching, the system achieves microsecond-level response times. This electronic substitution eliminates the inherent delay of fuse melting and magnetic trip mechanisms, resolving the contradiction between providing protection and maintaining fast reaction time.
3Reliability
If the charging current is interrupted by the fuse before the switch-off unit can react, then the charging current is interrupted, but the functionality of the electric vehicle is lost and manual intervention is required
Solution Approach 1:
The patent replaces the irreversible mechanical fuse operation with a reversible electronic switching system. When a malfunction occurs, the power semiconductor components are electronically controlled to interrupt the charging current. After the malfunction is resolved, the system can be reset and the charging current restored without requiring physical replacement or manual intervention, thus eliminating vehicle downtime.
Solution Approach 2:
The switch-off unit enables the system to discard the faulty charging state and recover normal operation quickly. By using electronic switching instead of fuse replacement, the system can rapidly transition from a protected state to a normal operating state, minimizing the loss of time and maintaining vehicle functionality.
Data Source
AI summary
The invention relates to a switch-off unit (1, 1.1, 1.2, 1.3, 1.4, 1.5) for an electric charging device (3, 25, 27) with a switch-off arrangement (5, 5.1, 5.2, 5.3, 5.4, 5.5) having a first controllable power semiconductor component (9, 9.1) and a second controllable power semiconductor component (9, 9.2), and a switch-off control device (7), whereinthe first power semiconductor component (9, 9.1) and the second power semiconductor component (9, 9.2) are arranged antiserially, whereinthe first power semiconductor component (9, 9.1) and the second power semiconductor component (9, 9.2) are configured to conduct a charging current of the charging device (3, 25, 27) in a switched-on state, whereinthe switch-off control device (7) is operatively connected to the first power semiconductor component (9, 9.1) and the second power semiconductor component (9, 9.2) and is configured for their respective control, whereinthe switch-off control device (7) 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 (9, 9.1) and/or the second power semiconductor component (9, 9.2) and thereby interrupt the charging current.