Vehicle Electrical Switching Layout for Safe DC Charging
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Solution Overview
Problem
Existing vehicle electrical systems with different nominal voltages face challenges in preventing excessive contact voltages during charging and driving, particularly due to high Cy capacitances in electric drives.
Innovation Solution
A vehicle electrical system design incorporating a changeover switch and switching devices that allow the high-voltage consumer to be connected either to the rechargeable battery or to the DC charging connection, thereby disconnecting the DC charging connection from the first path and isolating high voltages to prevent contact voltage issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the high-voltage consumer is connected to the DC charging connection, then charging can be performed, but excessive contact voltages occur due to high Cy capacitances in the first path
Solution Approach 1:
The electrical system is segmented into two separate paths: a first path for driving mode containing the high-voltage consumer and Cy capacitances, and a second path for charging mode connected to the DC charging connection. The changeover switch segments the connection, allowing the system to operate in charging mode without the harmful Cy capacitances affecting the DC charging connection, thus preventing excessive contact voltages while maintaining charging capability.
2Object-affected harmful factors
If the high-voltage consumer is disconnected from the DC charging connection, then excessive contact voltages are prevented, but the high-voltage consumer cannot be supplied with voltage during charging
Solution Approach 1:
The changeover switch provides dynamic reconfiguration of the electrical system, allowing transition between driving mode and charging mode. During charging mode, the switch dynamically connects the high-voltage consumer to the DC charging connection through the second path, ensuring voltage supply while keeping the Cy capacitances isolated. This dynamic switching resolves the contradiction by adapting the connection topology to the operational mode.
Data Source
AI summary
A vehicle electrical system is equipped with at least one high-voltage consumer, a DC charging connection a rechargeable battery, a rectifier and a changeover switch. The high-voltage consumer is connected to the rechargeable battery by the changeover switch via a first switching device in a first switching position of the changeover switch and is connected to the rechargeable battery by the changeover switch in a second switching position of the changeover switch via a second switching device, wherein the DC charging connection is connected to the rechargeable battery via the first switching device.