EV Traction Power Network Switching for Low-Voltage Fault Isolation
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Solution Overview
Problem
Existing traction power supply systems for electric and hybrid vehicles are complex and lack efficient mechanisms to ensure power supply to the low-voltage side in the event of faults in the high-voltage components.
Innovation Solution
A traction power supply system with a high-voltage side and low-voltage side connected via a DC-DC converter, featuring switching elements and a control device to manage power distribution, allowing independent switching off of high-voltage components and ensuring power continuity to the low-voltage side, with optional bidirectional DC-DC converters and additional connection lines for enhanced fail-safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high-voltage side and low-voltage side are connected via DC-DC converter with switching elements, then power supply reliability to low-voltage side is improved, but device complexity increases
Solution Approach 1:
The traction power supply system is divided into a high-voltage side and a low-voltage side, with independent switching elements (first switching element between high-voltage battery and inverter, second switching element between high-voltage battery and DC-DC converter) that can independently control power flow paths. This segmentation allows faulty components on the high-voltage side to be isolated without affecting the low-voltage side power supply.
Solution Approach 2:
The DC-DC converter acts as an intermediary between the high-voltage side and low-voltage side, enabling independent control of power transmission. The converter allows the low-voltage side to receive power from the high-voltage battery through a dedicated path that can operate independently of the inverter, thus improving reliability while managing complexity through functional mediation.
2Reliability
If switching elements are added to isolate faulty components, then system safety is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses separate switching elements for different functional paths: a first switching element controls the connection between the high-voltage battery and the inverter, while a second switching element controls the connection between the high-voltage battery and the DC-DC converter. This segmentation enables independent isolation of faulty components, improving system safety while maintaining manageable manufacturing complexity through modular design.
3Reliability
If independent switching paths are created for high-voltage battery connections, then fail-safety is improved, but device complexity increases
Solution Approach 1:
The patent implements independent switching paths by placing a first switching element in the connection line between the high-voltage battery and the inverter, and a second switching element in the connection line between the high-voltage battery and the DC-DC converter. This segmentation creates redundant power supply paths, allowing the system to maintain fail-safety by isolating faults in one path without affecting the other, thereby improving reliability while managing complexity through structured design.
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
Ensures reliable power supply to the low-voltage side by isolating faulty high-voltage components, preventing repercussions, and utilizing the high-voltage battery and electrical machine to support the low-voltage side, thereby enhancing system reliability and safety.
Implementation Method 1
the high-voltage side is connected to the low-voltage side via at least one DC-DC converter
Implementation Method 2
the defective part of the traction power supply system can be switched off and the low-voltage side can still be supplied with power
Data Source
AI summary
A traction power supply system of an electric or hybrid transportation vehicle having a high-voltage side and a low-voltage side, wherein at least one electrical machine, an inverter and a high-voltage battery are arranged on the high-voltage side, wherein the high-voltage side is connected to the low-voltage side via at least one DC-DC converter, wherein the high-voltage battery is assigned at least one switching element, wherein the traction power supply system has at least one control device which controls the switching element, wherein the at least one switching element is arranged in at least one connection line between the high-voltage battery and the inverter, wherein the high-voltage battery is connected to the DC-DC converter via at least one further connection line. Also disclosed is a method for controlling a traction power supply system.