Inverter Half-Bridge Fault Interruption During EV Charging
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Solution Overview
Problem
Existing electric vehicle charging systems face the risk of destruction due to faults in the upper circuit breaker of the inverter's half-bridge, particularly when the vehicle battery's high voltage is permanently applied to a charger configured for lower voltage, leading to potential damage.
Innovation Solution
A method and device that utilize a fuse integrated with the power source, specifically a mechanical, electronic, or semiconductor switch, to rapidly interrupt the charging process by closing a lowside switch of the inverter's half-bridge upon detecting a fault in the highside switch, thereby preventing excessive current flow and potential damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper circuit breaker of the inverter's half-bridge fails and remains closed, then the vehicle battery's high voltage is permanently applied to the charger, but this leads to potential destruction of the charging station
Solution Approach 1:
The patent implements preliminary protective action by detecting faults in the upper circuit breaker before they can cause damage to the charging station. The control unit continuously monitors the state of the upper circuit breaker and, upon detecting a fault condition, proactively closes the lower circuit breaker to create a protective short circuit that prevents high voltage from reaching the charger.
Solution Approach 2:
The patent converts the harmful effect of a stuck-closed upper circuit breaker into a beneficial protective mechanism. By intentionally creating a controlled short circuit through the lower circuit breaker, the system transforms what would be a destructive high-voltage condition into a safe protective state that isolates the charging station from damage.
2Object-affected harmful factors
If a fuse is used to protect against high currents, then damage to the charging station is prevented, but the response time and speed of fault interruption must be sufficient
Solution Approach 1:
The patent replaces traditional mechanical fuse systems with an electronic control-based protection mechanism. The control unit electronically detects faults and actuates the lower circuit breaker through electronic control signals, achieving much faster response times compared to mechanical fuses that rely on thermal or magnetic trip mechanisms.
Solution Approach 2:
The patent changes the operational parameters of the circuit breakers from passive protective devices to actively controlled switches. By using the control unit to monitor voltage, current, and breaker state parameters in real-time, the system can detect faults and initiate protective action based on parameter thresholds, achieving rapid response without the delays inherent in passive fuse operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents destruction of the charging power source by quickly and safely interrupting the charging process, minimizing damage and requiring no additional circuitry, with the fuse tripping rapidly to protect against high currents.
Implementation Method 1
A fuse is arranged between the positive terminal of the power source and the positive input terminal of the inverter. Advantageously, corresponding fuses open in a very short time when the short-circuit current becomes very large within a short time.
Data Source
AI summary
The present invention relates to a method (500) for interrupting a charging process of a power source (230) of an electric drive (200), having the steps of: detecting (510) a fault at a highside switch (231, 233, 235) of a first half-bridge of the inverter (210); and closing (520) a lowside switch (232, 234, 236) of a half-bridge of the inverter (210).